tag:blogger.com,1999:blog-10259321218288781432024-02-18T21:08:59.984-08:00PLC.comAnonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.comBlogger34125tag:blogger.com,1999:blog-1025932121828878143.post-85109882502951070922012-01-18T04:42:00.000-08:002012-01-18T04:42:46.913-08:00SOPA, PIPA: What you need to know<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHWnS_fLJfx9oRbPGTEr77j2EuIxFKAMbUQpHgt89nGJyx4g1ZMXpbRFbA9HcjstPjx-3PPypzgLntI44FXgGijP21TeH3VlLqwMKtnv8fNtw-azj3iTu_lAZaMZVGcs3hYpxf9xdqYLJr/s1600/SOPA.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHWnS_fLJfx9oRbPGTEr77j2EuIxFKAMbUQpHgt89nGJyx4g1ZMXpbRFbA9HcjstPjx-3PPypzgLntI44FXgGijP21TeH3VlLqwMKtnv8fNtw-azj3iTu_lAZaMZVGcs3hYpxf9xdqYLJr/s320/SOPA.jpg" width="320" /></a></div>I’m sure you be familiar with by now that SOPA is bad and would damage the On the internet, but have you actually study the bill? If not, it’s value examining, for two factors. First, if you are going to fight a expenses, you should know exactly what you are opposition, not just the imprecise concept behind it. Second, it’ll offer you with a useful insight: that these charges are published in an try to hidden the reality of the matter.<br />
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Having problems using Wikipedia today? That's because the well-known crowd-sourced online encyclopedia is doing an "Internet blackout" in demonstrate of two debatable anti-piracy bills: The Quit On the internet Piracy Act (SOPA) and its Us senate associate, the Secure IP Act (PIPA).<br />
Why articles suppliers want SOPA and PIPA<br />
<br />
Content categories like the Movement Image Connections of The united states (MPAA), and business associates like the U.S. Step of Business, dispute that advancement and work in content-creating businesses are confronted by growing Online piracy. Offshore internet sites, they dispute, are a safe place for Online angry benefiting off their articles.<br />
<br />
According to the International Perceptive Property or home Center, which is part of the U.S. Step of Business, intellectual property-intensive categories implement more than 19 thousand individuals in the U.S. and create $7.7 billion in major result. Offshore website employees currently outside the range of U.S. law; SOPA and PIPA would help quell bogus Online action.<br />
<br />
In a report, former Sen. Bob Dodd, who is now chairman and CEO of the MPAA, known as the electrical outage day a "gimmick."<br />
<br />
"It's a risky and unpleasant progression when the systems that provide as gateways to information deliberately alter information to stimulate their customers in order to further their business pursuits," Dodd said.<br />
<br />
CBS Business, which operates CBSNews.com, is a associate of the Trademark Partnership -- an market team which represents articles manufacturers that can manage SOPA and PIPA.<br />
<br />
Why Online organizations fight SOPA and PIPA<br />
<br />
Internet organizations and their traders would easily say that they're positioning the "blackout" to secure their business pursuits -- and the whole growing Internet-based financial climate.<br />
<br />
"The achievements of Stumbleupon... is one of small sized illustrations of the achievements that has occurred in our market -- and will continue to unless charges like SOPA or PIPA become law," Ohanian said Wednesday.<br />
<br />
Under the guidelines SOPA or PIPA would encourage, Ohanian and others dispute, start ups wouldn't be able to deal with the costs that come with protecting their internet sites against possible offenses. Such internet sites would not be able to pay the large categories of attorneys that founded internet sites like The search engines or Myspace can manage.<br />
<br />
The regulation in question objectives foreign organizations whose main objective is to sell taken or replica products -- but competitors say every day organizations could still be presented responsible for connecting to their articles. While internet sites like Stumbleupon wouldn't have a legal obligation to keep track of their internet sites all the time, "you might have your jeans charged off of you" if you don't, said Jayme White, personnel manager for the Us senate Finance Subcommittee on worldwide business.<br />
<br />
Brad Burnham, dealing with lover at the investment investment finance Partnership Rectangle Efforts, said his organization has prevented committing in organizations related to the music business because of the copyright threats -- but under the recommended regulation, that possibility would hit just about any Company online. SOPA and PIPA, he said, "takes the chance of irs lawsuit... to the whole Online."<br />
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That should be a dilemma, Burnham said, when the Online records for 21 percent of financial development among designed countries, according to one research.<br />
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The has an impact on could go beyond the financial climate, some dispute. Rebecca MacKinnon, a mature other at the nonpartisan New The united states Groundwork, claims that if running a blog systems are encouraged to keep track of their articles, that could have "a incredible relaxing impact on individuals tyring to perform governmental discussion and trying to use articles in a reasonable use perspective."<br />
<span class="fullpost"> </span></div>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-33928831986838286412011-01-04T13:56:00.000-08:002011-01-04T14:56:37.266-08:00Step by step guide which helps you build your own PC.Step by step guide which helps you<a href="http://plc-kita.blogspot.com/2011/01/step-by-step-guide-which-helps-you.html"><b><i> build your own PC</i></b></a> (in video).<span class="fullpost"> </span><br />
<object height="385" width="640"><param name="movie" value="http://www.youtube.com/v/QQQ30QoF_-8?fs=1&hl=en_US&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/QQQ30QoF_-8?fs=1&hl=en_US&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object><br />
<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B002V3C4F8&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=FFFFFF&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-45853673335320578092010-12-23T14:24:00.000-08:002010-12-23T14:57:49.606-08:00vb.net My SQL Tutorial 1<span class="fullpost">hi all this is the first tutorial of 7 series vb.net My SQL Tutorial..happy reading :) </span><object id="_ds_66399521" name="_ds_66399521" width="700" height="550" type="application/x-shockwave-flash" data="http://viewer.docstoc.com/"><param name="FlashVars" value="doc_id=66399521&mem_id=6175513&doc_type=pdf&fullscreen=0&allowdownload=1" /><param name="movie" value="http://viewer.docstoc.com/"/><param name="allowScriptAccess" value="always" /><param name="allowFullScreen" value="true" /></object><br /><script type="text/javascript">var docstoc_docid="66399521";var docstoc_title="vb.net My SQL Tutorial 1";var docstoc_urltitle="vb.net My SQL Tutorial 1";</script><script type="text/javascript" src="http://i.docstoccdn.com/js/check-flash.js"></script><font size="1"><a href="http://www.docstoc.com/docs/66399521/vbnet-My-SQL-Tutorial-1">vb.net My SQL Tutorial 1</a></font>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-51741715200520552532010-08-05T15:43:00.000-07:002010-08-05T15:43:03.644-07:00UPS<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiefCgsW9SmZ0CXhkIdZXPV_ycPl0Yd15HdLT9Lvc41Gy_tIrmCsuQjeVr7NUC5tQocpgxdbuTyq3_kldMbU5jbCCu9I8voCn2bGlQHZSNfIYjregTIlpOcHivu2CI8AhENVOmGMw1Jyw-9/s1600/UPS.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="UPS"border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiefCgsW9SmZ0CXhkIdZXPV_ycPl0Yd15HdLT9Lvc41Gy_tIrmCsuQjeVr7NUC5tQocpgxdbuTyq3_kldMbU5jbCCu9I8voCn2bGlQHZSNfIYjregTIlpOcHivu2CI8AhENVOmGMw1Jyw-9/s320/UPS.jpeg" title="UPS"/></a></div>Of late, you use a number of things which run by electricity. Frequent power cuts leave you paralyzed therefore the idea of <span class="IL_AD" id="IL_AD1">uninterruptible power supplies</span> (UPS) came in existence. The uninterruptible power supplies are designed to avoid power trips and cuts as brings power supply as soon as it experiences power failure. This gadget can be seen everywhere from houses to offices to industrial plants to hospitals. Ranging from 200VA to 4.8mVA, most of UPS in the country comprise of a battery pack and an input and output phase.<br />
<br />
<i>Knowing extensively about uninterruptible power supplies </i><br />
<br />
Also recognized as a continuous power supplies or a battery backup, uninterruptible power supplies are devices assist in maintaining a continuous supply of electric power to connected devices and equipments by supplying power from a separate source when utility power gets failed. UPS is popular than <span class="IL_AD" id="IL_AD4">standby generator</span> as the generator does not provide instant power for a momentary power interruption. <br />
<br />
Different types of UPS<br />
<br />
There are three types of uninterruptible power supplies available in the UK include:<br />
<br />
• Online or Double Conversion<br />
• Line Interactive<br />
• Offline (or Passive Standby)<br />
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The type of UPS depends upon the requirements of customers. Market is packed from low budget to high budget devices; you can buy according to your use. <br />
<br />
Knowing about the components of the device<br />
<br />
Your UPS and other electronic devices are comprised of components such rectifier, charger, battery, inverter, maintenance bypass and static switch which make them work effectively and efficiently. Each component has its own area of specification. Comprising of a series of battery backups, they employ DC to convert it to AC and thus it is useful for your appliances. <br />
<br />
Why are online stores preferred for uninterruptible power supplies?<br />
<br />
The internet has been considered as an economical option for buying UPSes and their accessories. Apart from cost effective, it brings exclusive and vital products for wide range of customers. After searching a reliable and genuine online UPS store, you need to fill in its <span class="IL_AD" id="IL_AD2">online order form</span> and send it to the mentioned address for further course of action. So, why are you thinking of?Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-15245693296886184902010-07-24T20:11:00.000-07:002010-07-24T20:11:06.071-07:00Building your own computerHave you ever dream to<i><b> building your own computer</b></i>? Actually buying a motherboard and a case along with all the supporting stuff and assembling the whole thing by yourself?<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUs2eXQfE7YmC-50PCILvEJ5yoNrUqzd3pESZzIHLy32O96u21agDwgtOkipTJXH1QjsMWJFZy6g-ERPtOfagurat1WaHxB1MVi3EVAvz83b9u2rRouiOfJVznRLS9vYqgEvwLvMWnGzvc/s1600/build_a_computer.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUs2eXQfE7YmC-50PCILvEJ5yoNrUqzd3pESZzIHLy32O96u21agDwgtOkipTJXH1QjsMWJFZy6g-ERPtOfagurat1WaHxB1MVi3EVAvz83b9u2rRouiOfJVznRLS9vYqgEvwLvMWnGzvc/s320/build_a_computer.jpg" /></a></div><br />
Here are 3 reasons why you might want to consider taking the plunge:<br />
<br />
<ol><li>You can create a custom machine that exactly matches your needs.</li>
<li>It will be much easier to upgrade your machine in the future because you will understand it completely.</li>
<li>You may be able to save a lot of money.</li>
</ol>And, if you have never done it before in your live, you will definitely learn a lot about computers.<br />
In this article, we'll take you through the entire process of building a computer. You'll learn how to choose the parts you will use, how to buy them and how to put them all together. When you're done, you will have exactly the machine that you need. Let's get started.<br />
<br />
The first step in building a computer is deciding what type of machine you want to build. Do you want a really inexpensive computer for the kids to use? A small, quiet machine to use as a media computer in the living room? A high-end gaming computer? Or maybe you need a powerful machine with a lot of disk space for <b><i>video editing</i></b>. The possibilities are endless, and the type of machine you want to build will control many of the decisions you make down the line. Therefore, it is important to know exactly what you want the machine to accomplish from the start. <br />
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Let's imagine that you want to build a powerful video editing computer. You want it to have a dual-core CPU, lots of RAM and a terabyte of disk space. You also want to have FireWire connectors on the motherboard. These requirements are going to cause you to look for a motherboard that supports:<br />
<ul><li>Latest multi core processor (either Intel or AMD)</li>
<li>At least 4GB of high-speed RAM</li>
<li>Four (or more) SATA hard drives</li>
<li>FireWire connections (possibly in both the front and back of the case)</li>
</ul>Then it all needs to go in a case with enough space to hold multiple hard disks and enough air flow to keep everything cool.<br />
With any computer you build, knowing the type of machine you want to create can really help with decision-making.Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-34609722259725514632010-07-24T19:15:00.000-07:002010-07-24T19:15:52.007-07:00Refurbished laptopNow people begin to start searching for cheaper options as they are having a low budget, under which they want something more reliable and durable. So the maker started to make an strategy in which they offer off-leased computers and laptops on cheap prices which are in range of a budget oriented buyer.<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0c7x7TvRipFQBKLtItchSkeQtX-ri9cQSVbRlS3J0OHLE9TLkpnn5Q03kaK1B7CoA0dBl5bXv0auddqQcJkZkd5H0-A1eB-PqWJ0yCCkdcXxk9r5vGs9A4BBwW47Av1rnqrsaqsH8MsVW/s1600/laptop_laptop-internal.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0c7x7TvRipFQBKLtItchSkeQtX-ri9cQSVbRlS3J0OHLE9TLkpnn5Q03kaK1B7CoA0dBl5bXv0auddqQcJkZkd5H0-A1eB-PqWJ0yCCkdcXxk9r5vGs9A4BBwW47Av1rnqrsaqsH8MsVW/s320/laptop_laptop-internal.jpg" /></a></div>Some of the people has started to think that these off-leased/<span class="IL_AD" id="IL_AD3">refurbished systems</span> which <i><b>laptop </b></i>maker are giving on low prices are faulty ones, and they just want to increase their market share that's why they are giving out these <span class="IL_AD" id="IL_AD1">low priced laptops</span> or systems.<br />
Well perceptions can be changed too, by giving them more authenticated information and good quality products in low prices. Refurbished systems are checked by the manufacturing company because if they sell out a faulty PC then it's a matter of their reputation and they might have to face some legal challenges, so they make sure that what they are offering in refurbished condition should be thoroughly checked and tested so that customer who buys these systems and laptops should not face any kind of problems.<br />
<span class="IL_AD" id="IL_AD4">Cheap computers</span> does not always means that they are cheap so they won't be good, cheap computers are cheap because they are used ones, but they sometime comes with very good specifications too which can easily get a client what they are looking for. In the end Refurbished Computers or Cheap Computers are a good option for all people who want to use a computer by investing low amount of bucks.<br />
Student who have tense budget, you can have a fastidious <strong><span class="IL_AD" id="IL_AD2">Refurbished hp</span> desktop computer</strong> for your academy work without contravention your budget.<br />
Those who have an undersized business this is a good means to make available all workers with an upright laptop or computer and save on your corporation everyday expenditure.<br />
Parents with young children need to have a computer so you can make stay them away of mom and dad's computer then find them a reasonably priced <strong>Refurbished hp desktop computer!</strong><br />
Designers, architects who run mostly heavy design software can also use <strong>Refurbished hp desktop computers </strong>for their and client presentations. Officially <strong>Refurbished hp desktop computers </strong>can provide heavy data storage if you get huge hard disk.Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-33544894379840889762010-07-24T05:01:00.000-07:002010-07-24T05:01:55.665-07:00Sony Vaio VPCY11S1E/S<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzy6UQbBKSjIiqnOUcUAS299ode_aBqRbBif5l078gIigsXIw_5eRc42Z5e99wZObDT-uvDO9YPFlG6a_T8fenfl0aZTUKaK2OmEg9Ekuc1EGVxf1FwgAb_SegyuNp0mu5yd4SqWUc_2QA/s1600/Sony_Vaio_Vpcy_11S1E-s.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzy6UQbBKSjIiqnOUcUAS299ode_aBqRbBif5l078gIigsXIw_5eRc42Z5e99wZObDT-uvDO9YPFlG6a_T8fenfl0aZTUKaK2OmEg9Ekuc1EGVxf1FwgAb_SegyuNp0mu5yd4SqWUc_2QA/s320/Sony_Vaio_Vpcy_11S1E-s.jpg" width="320" /></a></div>Plenty of laptop maker deliver their own <span class="IL_AD" id="IL_AD3">notebook</span> computers in a variety of styles, although the Sony corp happens to be on this for longer as compared to most. You can certainly trace that all the way back again towards C Line around Feb 2007, which was swapped out with the CR Line within August that time and then the CS Series last year. However, while the outgoing CR was rather practical, the CS has been very a considerable step backward, therefore experts were not stunned to find out it quickly changed by the Sony <b><i>Vaio VPCY11S1E/S</i></b> laptop together with the advent of <i>Windows 7</i>.<br />
<br />
There are 5 colors accessible: white, red, pink, blue and black. Any pink version no matter individual desire, is most likely the least likable preference of them all. Even consumers that like pink <span class="IL_AD" id="IL_AD4">will see</span> that the brighter, additional energetic shade viewed over the lid and hand rest does not sit properly using the somewhat sickly, pale shade applied on the rest in the laptop. No real issues may be made on the alternative options, even though, and we all especially prefer the red/black and white designs.<br />
<br />
As for the general style, the <i><b>VPCY11S1E/S</b></i> isn't really a type icon, however it's yet another solid, incredibly properly set together laptop computer coming from Sony. While competitors tend to over complicate their models in an effort to stand out, Sony achieves to create a sense of type in a very far a lot more restrained approach. Every thing is within the correct place and posesses function, leaving your selection of coloration to make the statement - in the event that's what you're after.<br />
<br />
Option isn't reduced only to colour, either. Even though we are reviewing one particular in the retail bound SKUs, which go for among £650 and £700 determined by where you shop, Sony provides modification possibilities via their web site. Options are not that varied, however it is possible to select fewer RAM, weaker graphics, reduced CPUs and a resulting £579 starting cost or perhaps advancements that consist of a 500GB <span class="IL_AD" id="IL_AD6">hard disk</span> and Blu-ray disk, delivering somewhat flexibility.<br />
<br />
Connectivity is not too poor, either. Whilst the VPCY11S1E/S laptop doesn't have eSATA or USB 'sleep and charge' abilities, it does have got mini-FireWire - an increasingly hard to find terminal on laptop computers lately. Every thing else is fairly regular, such as: 3 USB ports (2x left, 1x right); High-definition multimedia interface along with VGA for video; a 34mm ExpressCard port, sound jacks (1x earphone, 1x mic); an Ethernet port on the back as well as separate <span class="IL_AD" id="IL_AD5">memory card</span> slots for Sony's proprietary types as well as the extra commonly utilized SD card format.<br />
<br />
Yet another strength of this <b><i>Sony Vaio VPCY11S1E/S</i></b> is its display screen. Measuring 14.1in and when using the industry standard 1,366 x 768 native resolution it's not a masterpiece, it still experiences the comparatively shallow watching perspectives and glossy, reflective coatings of all notebook computers within this sector and value. But colours are just somewhat punchier, black levels a little bit deeper and whites a tad cleaner when compared with the normal, doing it greater in comparison with several we can come across.<br />
<br />
Equivalent plaudits may be granted towards the accompanying <span class="IL_AD" id="IL_AD2">touchpad</span>. For starters it is large enough which the currently stylish multi-touch assistance is really helpful, unlike the recent Toshiba Satellite U500. The surface is actually completely clean, though the two buttons seem to be independently hinged thereby provide outstanding tactile response. If you are ever in doubt about precisely what you get if you ever spend a bit more on a brand just like Sony, this sort of finer details should really convince.<br />
<br />
And what better way to enjoy such video clips compared to making use of your very own instant-on <span class="IL_AD" id="IL_AD7">internet browser</span>? It really is no Google Chrome OS, but pushing the 'Web' key above the <span class="IL_AD" id="IL_AD1">laptop keyboard</span> will take you from nothing to a internet page in about Twenty secs. This is really a really neat function that is well implemented.Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-41084839592657797722010-06-10T06:05:00.000-07:002010-06-10T06:05:00.537-07:00iPad webcam Accesory from PhotoFast<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihCdQ_YA4V6yNc-9YvXOD1soaG0DfwKuLUw-ZcmckcgSJE2YfpPXeXnQcGus9JdXVCNx1-c6nB8gSfItAYXUd19VOTLKxRIDVONvRHq8DhH_UTGmUD3kfed1zkSjifVvMvGn6dB_etRbYb/s1600/iPad_webcam_accesory.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="221" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihCdQ_YA4V6yNc-9YvXOD1soaG0DfwKuLUw-ZcmckcgSJE2YfpPXeXnQcGus9JdXVCNx1-c6nB8gSfItAYXUd19VOTLKxRIDVONvRHq8DhH_UTGmUD3kfed1zkSjifVvMvGn6dB_etRbYb/s400/iPad_webcam_accesory.jpg" width="400" /></a></div><span id="intelliTxt" name="intelliTxt">The accessory is called the PhotoFast Webcam for iPad and it looks like any other webcam you would connect to a computer</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-40267243515305061942010-06-09T19:34:00.000-07:002010-06-09T19:34:58.397-07:00Dell - Inspiron Laptop with Intel® Core™ i3 Processor - Cherry Red<div id="boxcontents" style="font-family: times new roman;"> <div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuy299IsLRS6hnVHUKTlvuGNH_bLRQbf1d1Foo8v0IeZ5PzPLh7l7psM7oA5i5lfOYJqCI0ZJuotWIBaGjvFJecYMmneutXewgPJ-JY1pDBE2yAxWAVX2oyFb1rP1s_aw_PDc1cW9xnxqC/s1600/dell_inspiron_laptop_with_Intel_core_i3_processor.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuy299IsLRS6hnVHUKTlvuGNH_bLRQbf1d1Foo8v0IeZ5PzPLh7l7psM7oA5i5lfOYJqCI0ZJuotWIBaGjvFJecYMmneutXewgPJ-JY1pDBE2yAxWAVX2oyFb1rP1s_aw_PDc1cW9xnxqC/s320/dell_inspiron_laptop_with_Intel_core_i3_processor.jpg" /></a></div><h2><span style="font-size: 130%;"><span style="font-size: small;">Perfect gadget for PLC programing..</span></span></h2><h2><span style="font-size: 130%;"> What's Included</span></h2><ul class="p-v"><li class="property included-item"><span style="font-size: 130%;">Dell Inspiron Laptop with Intel® Core™ i3 Processor</span></li>
<li class="property included-item"><span style="font-size: 130%;">6-cell lithium-ion battery</span></li>
<li class="property included-item"><span style="font-size: 130%;">AC power cable</span></li>
<li class="property included-item"><span style="font-size: 130%;">Software: Microsoft Works and more</span></li>
<li class="property included-item"><span style="font-size: 130%;">Owner's manual</span></li>
</ul></div><!--Code snippet for displaying the DND_box_contents - end--><h2 style="font-family: times new roman;"><span style="font-size: 130%;">Product Features</span></h2><ul style="font-family: times new roman;"><li><span style="font-size: 130%;"><b>Intel® Core™ i3-330M processor</b><br />
Features a 3MB cache and 2.13GHz processor speed.</span></li>
<li><span style="font-size: 130%;"><b>Intel® Core i3 processor</b><br />
Features smart 4-way processing performance for HD quality computing. Intel® HD Graphics provide extra graphics power for your laptop when you need it.</span></li>
<li><span style="font-size: 130%;"><b>4GB DDR3 SDRAM</b><br />
For multitasking power, expandable to 8GB.</span></li>
<li><span style="font-size: 130%;"><b>Multiformat DVD±RW/CD-RW drive</b><br />
To create custom DVDs and CDs.</span></li>
<li><span style="font-size: 130%;"><b>15.6" glossy WLED high-definition widescreen display</b><br />
With TrueLife technology showcases movies and games in stunning clarity.</span></li>
<li><span style="font-size: 130%;"><b>320GB Serial ATA hard drive (5400 rpm)</b><br />
Offers spacious storage and fast read/write times.</span></li>
<li><span style="font-size: 130%;"><b>Intel® Graphics Media Accelerator HD</b><br />
For lush images. HDMI output for connecting to an HDTV. Built-in stereo speakers.</span></li>
<li><span style="font-size: 130%;"><b>Built-in 1.3MP webcam</b><br />
Makes it easy to chat with family and friends.</span></li>
<li><span style="font-size: 130%;"><b>7-in-1 media reader</b><br />
Supports Secure Digital, Secure Digital High Capacity, MultiMediaCard, MultiMediaCard Plus, xD-Picture Card, Memory Stick and Memory Stick PRO formats.</span></li>
<li><span style="font-size: 130%;"><b>3 high-speed USB 2.0 ports</b><br />
For fast digital video, audio and data transfer.</span></li>
<li><span style="font-size: 130%;"><b>Built-in Dell 1397 wireless LAN (802.11b/g) </b><br />
Wirelessly connect to the Internet.</span></li>
<li><span style="font-size: 130%;"><b>Built-in 10/100 Ethernet LAN</b><br />
For quick and easy wired Web connection.</span></li>
<li><span style="font-size: 130%;"><b>Weighs 5.4 lbs. and measures just 1.3" thin</b><br />
For easy portability.</span></li>
<li><span style="font-size: 130%;"><b>Long battery life</b><br />
Of up to 4 hours to give you more time away from an outlet.</span></li>
<li><span style="font-size: 130%;"><b>Microsoft Windows 7 Home Premium Edition 64-bit operating system preinstalled</b><br />
Provides a stable platform for word processing, Web navigation, gaming, media storage and more.</span></li>
<li><span style="font-size: 130%;"><b>Software package included</b><br />
With Microsoft Works and more.</span></li>
<li><span style="font-size: 130%;"><b>ENERGY STAR qualified</b><br />
Designed to use less energy and meets strict energy efficiency guidelines set by the Environmental Protection Agency and U.S. Department of Energy.</span></li>
<li><span class="Legal" style="font-size: 130%;">Intel, Pentium, Celeron, Centrino, Core, Viiv, Intel Inside and the Intel Inside logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries.</span></li>
</ul><span style="font-size: 130%;"><br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-43908671796923354832010-06-09T05:17:00.000-07:002010-06-09T05:17:27.582-07:00iPhone 4<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKLbfbb5FccFNmBD2TsG9qEi6N1dJtD4zVzy9vPvP8XWldohIV56lYSoNgFb__IiCPpAMHSTiPkidA3XnygEBc988CJaSLg4Az5oOzL5hRwpW9o4MNZDNBeqoDe2XfACNWSh0dx9lDSQZq/s1600/iPhone_4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKLbfbb5FccFNmBD2TsG9qEi6N1dJtD4zVzy9vPvP8XWldohIV56lYSoNgFb__IiCPpAMHSTiPkidA3XnygEBc988CJaSLg4Az5oOzL5hRwpW9o4MNZDNBeqoDe2XfACNWSh0dx9lDSQZq/s320/iPhone_4.jpg" /></a></div>Slimmer, brighter, more powerful and apparently the product of 18 months development: the Apple iPhone 4 certainly is something. The wwdc 2010 opening keynote is over, and we’ve just been back to check out the new Apple smartphone. Set to debut on June 24th – and up for preorder from June 15th – the Jobs hyperbole and press shots don’t do the iPhone 4 justice in your hand. Whether you are an Apple fan or not, you have to give them credit for creating a very slick deviceAnonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-4622875973854528922010-06-09T04:44:00.000-07:002010-06-09T04:44:29.343-07:00Sony VAIO P<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNf_vAUYjAfMR4PYVhkQVgdnM2XOyiu4Ht2XR2dBf-vSO45WGLaoLWmZu-_4R_lbHeUf5DXQn1pwtLO0scg5oVT5HRLa2lF5Qd7_jIVRXj2kSkWNMSyYVYMOAuYjUuTEv70peo2ObxHx3P/s1600/sony_VAIO_P.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNf_vAUYjAfMR4PYVhkQVgdnM2XOyiu4Ht2XR2dBf-vSO45WGLaoLWmZu-_4R_lbHeUf5DXQn1pwtLO0scg5oVT5HRLa2lF5Qd7_jIVRXj2kSkWNMSyYVYMOAuYjUuTEv70peo2ObxHx3P/s320/sony_VAIO_P.jpg" /></a></div>Sony’s second-gen VAIO P ultraportable has finally shown up for preorder on the company’s US SonyStyle webstore, priced from $899.99 and with deliveries expected to kick off from around June 25th 2010. The newly refreshed VAIO P packs a 1.6GHz Intel Atom Z530 processor paired with GMA 500 graphics, and comes in five different casing colorsAnonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-30665947468084303012010-04-30T00:02:00.000-07:002010-04-30T09:05:41.631-07:00Electronics Basic Symbol (just for kids)<span id="goog_1914703447"></span><span id="goog_1914703448"></span>Here are five basic symbols that you will find on electronic wiring diagrams, along with a brief definition. Look them over. When you get to #12 you can see if you remember the name of each symbol. <span class="fullpost"></span><br />
<span class="fullpost"><br />
</span><br />
<ul></ul><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_XpbYE0FFzg_UMriroTwxtFmhbS_4nSYHncyUYh6nATmhk2ux4trNcOM1P_IlIadnbT0D1h62sUhQjLuwBw_C0MkUbSZFQwfxuLCpXA-WSe9rUO3lLrfem_3_kXw4gIC_s4yI585QPz2L/s1600/batsymb.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_XpbYE0FFzg_UMriroTwxtFmhbS_4nSYHncyUYh6nATmhk2ux4trNcOM1P_IlIadnbT0D1h62sUhQjLuwBw_C0MkUbSZFQwfxuLCpXA-WSe9rUO3lLrfem_3_kXw4gIC_s4yI585QPz2L/s320/batsymb.gif" /></a><br />
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<ul><li><span class="fullpost">Battery--a DC (direct current) voltage energy source.</span></li>
</ul><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjwePIaToCgzVaSwWAb6z0Y41sRe957WWWUth89MBfd9GkZZP_mTFBcXKI5b3S-Nuuy1H_pjEVGsF6n32LC0FqI_vFs7mMItkCDYZ8C3bbobW_hbzHRzm6y49uCJMx-xmKDGpL4iK_eIpF/s1600/ground.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjwePIaToCgzVaSwWAb6z0Y41sRe957WWWUth89MBfd9GkZZP_mTFBcXKI5b3S-Nuuy1H_pjEVGsF6n32LC0FqI_vFs7mMItkCDYZ8C3bbobW_hbzHRzm6y49uCJMx-xmKDGpL4iK_eIpF/s320/ground.gif" /></a></div><br />
<br />
<ul><li><span class="fullpost">Ground--the common or reference point in an electrical circuit.</span></li>
</ul><br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHcTM006agHtf031ql0hQVT5mONKaHDavkhNzSMlWh9u38drooaXJhTbSN4vOjqsGP1Mt0CGx4JWNQyMXJf1PLSR9tLIIPOZ3FkbcViA5FaS2Nr5XtPv9zDC2tWwweQYKcY1Ek4e5twNCc/s1600/resistor.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHcTM006agHtf031ql0hQVT5mONKaHDavkhNzSMlWh9u38drooaXJhTbSN4vOjqsGP1Mt0CGx4JWNQyMXJf1PLSR9tLIIPOZ3FkbcViA5FaS2Nr5XtPv9zDC2tWwweQYKcY1Ek4e5twNCc/s320/resistor.gif" /></a><br />
<br />
<br />
<br />
<ul><li>Resistor--an electrical component that opposes current.</li>
</ul><br />
<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgP10Z6-GPn8vOL5RQuYuuYw2-nX60WWvcGJip4mIdmFamh4hOPMbrSkLaX4pwEIPrlfaEOlQR1i-zlLgWMAaMIpY9GS1XIaLyrlM5fFqfoUqM0w2VvgW0d4Hb54_2FPl7e57NMlaqmY1vZ/s1600/cap.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgP10Z6-GPn8vOL5RQuYuuYw2-nX60WWvcGJip4mIdmFamh4hOPMbrSkLaX4pwEIPrlfaEOlQR1i-zlLgWMAaMIpY9GS1XIaLyrlM5fFqfoUqM0w2VvgW0d4Hb54_2FPl7e57NMlaqmY1vZ/s320/cap.gif" style="cursor: move;" /></a><br />
<br />
<br />
<ul><li>Capacitor--an electrical device that can store an electrical charge.</li>
</ul><br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBJA2CNz_6vBwiogZtBsH7kwGc5aEzrFSt29oGiYkxxeDBQ2GLBrj8MfMNG2lxUobieNEYQRruVcbiNUjEVlZ6mkPEoSV8lQAvIS4Ka20S-hjekhkbuDvCmahanDunkZL9l_CFJN3g7Cnx/s1600/diode.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBJA2CNz_6vBwiogZtBsH7kwGc5aEzrFSt29oGiYkxxeDBQ2GLBrj8MfMNG2lxUobieNEYQRruVcbiNUjEVlZ6mkPEoSV8lQAvIS4Ka20S-hjekhkbuDvCmahanDunkZL9l_CFJN3g7Cnx/s320/diode.gif" /></a><br />
<br />
<ul><li>Diode--a one-way conductor that allows current to flow only in one direction.</li>
</ul><br />
<br />
<br />
<br />
<ul></ul><span class="fullpost"> <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B000GCG9U2&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe> <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B0002OP83I&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B000Z4RKSQ&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><br />
<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-22449658065172372242010-04-26T06:43:00.000-07:002010-04-26T06:43:07.816-07:00CCTV camera<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=widgetsamazon-20&o=1&p=8&l=bpl&asins=B000A4AVRS&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>Network Camera STC-IPM3096A allows for round the clock surveillance in the "Day" / "night" in all light up 0.4/0.06 lux, and forms an image with resolution up to 1280 × 960 pixels. It can be broadcast on the network simultaneously two customized stream video M-JPEG format and / or MPEG-4.<br />
<br />
In addition, STC-IPM3096A has motion detector, equipped with 2 GB SD-card memory, alarm inputs / output, audio inputs / outputs for audio link between the operator and the area of observation and supports PoE. Setting up the camera can be carried out through a web browser or with the NetStation.<span class="fullpost">IP-camera is capable of transmitting on the network to two video streams simultaneously in the MPEG-4 and / or M-JPEG with resolution settings and the framerate each. In the M-JPEG format with a maximum resolution of the image STC-IPM3096A can reach SXVGA (1280 × 960 pixels.) With frame rate 10-15 fps. Increase framerate flow up to 25 fps in this format by specifying the resolution VGA (640 × 480 pixels.) Or QVGA (320 × 240 pixels.).In MPEG-4 IP-megapixel camera capable of transmitting video VGA-standard full-frame mode Low, Middle, and High. To optimize the video stream in the M-JPEG for bandwidth video, you can choose the degree of video compression: Low, Middle or High.<br />
<br />
<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=widgetsamazon-20&o=1&p=8&l=bpl&asins=B001764PVQ&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>Record and store video and audio c IP-camera can be carried out on a network video recorder (NVR), PC hard drive or external disk drives and arrays. For temporary storage of data, including anxiety, designed SD-card memory capacity of 2 GB, which is supplied STC-IPM3096A. This IP-megapixel camera can record video on a map constantly, cyclically updating archive as it is filled, or just disturbing video. Efficient operation IP-camera in the security video provided by the hardware motion detector, alarm inputs, which can connect an external alarm sensors, and alarm output, through which you can manage the work of executive device. Built-in STC-IPM3096A VMD has the three levels of sensitivity and allows you to set up 48 areas of detection of 8x6 square grid elements. In the basic setup IP-camera "reacts" to the alarm event lasting no less than 100 milliseconds, but in order to avoid false positives during her reaction may be increased to 60 seconds. Thanks to the audio input / output cell </span><br />
<br />
<span class="fullpost">STC-IPM3096A lets you listen to the zone of its installation or to arrange two-way audio with the operator of the security services. </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com1tag:blogger.com,1999:blog-1025932121828878143.post-50861609009890140862010-04-26T06:05:00.000-07:002010-04-26T06:46:33.110-07:00Aircraft Receiver<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR5fSsCnKTZPfij5I92Gc-PjHW3t92zTK784WstyxoiiK8IGqtWbIspCTuGIkEx5d7RSBEkGYgN2CT6nUlQEEWFz1glsh3zy-hS4EtKgWtM_YCHwuFx4G9JuZoesr9aJ9JYsw0hobFJwUW/s1600/aircraft+receiver.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="195" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR5fSsCnKTZPfij5I92Gc-PjHW3t92zTK784WstyxoiiK8IGqtWbIspCTuGIkEx5d7RSBEkGYgN2CT6nUlQEEWFz1glsh3zy-hS4EtKgWtM_YCHwuFx4G9JuZoesr9aJ9JYsw0hobFJwUW/s400/aircraft+receiver.gif" width="400" /></a></div><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=0470289619&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>The Passive Aircraft Receiver is basically an amplified "crystal radio" designed to receive nearby AM aircraft transmissions. The "passive" design uses no oscillators or other RF circuitry capable of interfering with aircraft communications so it should be fine inside the cabin of the aircraft. Nevertheless, check the regulations before using this receiver on a commercial airliner.<br />
<br />
New security regulations probably prohibit this device on commercial flights. Do not expect to hear two-way aircraft transmissions with this receiver! It is a short-range receiver only.<span class="fullpost">The detector diode is a 1N5711, HP2835 or similar Schottky detector diode. The 10 megohm resistors provide a small diode bias current for better detector efficiency. The tuning capacitor may be any small variable with a range from about 5 pF to about 15 or 20 pF. The 0.15 uH inductor may be a molded choke or a few turns wound with a small diameter. Experiment with the coil to get the desired tuning range. The aircraft frequencies are directly above the FM band so a proper inductor will tune FM stations with the <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=0486210766&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>capacitor set near maximum capacity. (The FM stations will sound distorted since they are being slope detected.) Other capacitor and inductor combinations may be selected to tune other bands if desired. (Try the CB band at 27 MHz.) The LM358 dual op-amp draws under 1 ma so the battery life is quite long. A speaker amplifier may be added to drive a speaker or low-z earphone. The antenna can be a couple of inches if the receiver is near the transmitter or a couple of feet for maximum range. The selectivity is reduce as the antenna length is increased so best performance is achieved with the shortest acceptable antenna. Try increasing the 1.8 pF capacitor value when using very short antennas and decreasing it for long antennas. The receiver could be built into a small plastic box with a short antenna inside. </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-39571121885721503482010-04-23T21:29:00.000-07:002010-04-23T21:29:29.795-07:00Battery tipes<div class="separator" style="clear: both; text-align: center;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B000RB60H4&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgs4NEItp6nfGVNK0Yo51mYx-fOQP7zPUuV2pl0r2GH4eDxgUS_8m1R-6avhxUvLAwqEqiG-2zz6vn7_DwQFpFD_cbs-hK2YQ5JgQp4rd79CaJj-E1kHR0iEqRY5MVPzNv-MW-diWJI0qSu/s1600/lemmon_battery_labels.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgs4NEItp6nfGVNK0Yo51mYx-fOQP7zPUuV2pl0r2GH4eDxgUS_8m1R-6avhxUvLAwqEqiG-2zz6vn7_DwQFpFD_cbs-hK2YQ5JgQp4rd79CaJj-E1kHR0iEqRY5MVPzNv-MW-diWJI0qSu/s200/lemmon_battery_labels.jpg" width="200" /><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B000RB60H4&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B000NPZ4TO&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B001T3Y8XW&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B001T3Y8XW&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B001T3Y8XW&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B001T3Y8XW&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"></iframe></a></div>Basically there are two types of batteries; starting (cranking), and deep cycle (marine/golf cart).<span class="fullpost">The starting battery (SLI starting lights ignition) is designed to deliver quick bursts of energy (such as starting engines) and have a greater plate count. The plates will also be thinner and have somewhat different material composition. The deep cycle battery has less instant energy but greater long-term energy delivery. Deep cycle batteries have thicker plates and can survive a number of discharge cycles. Starting batteries should not be used for deep cycle applications. The so-called Dual Purpose Battery is only a compromise between the 2 types of batteries. </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-87841343693014022812010-04-23T21:01:00.000-07:002010-04-23T21:01:16.551-07:00Battery safety tips<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguUNNoYxl71AzmPWGK5D-TZ3Kv7-nZB-aOYOnd0OZMIuMV2hyphenhyphentjahjYQH08o1xWeGiSUHp3j4Jwvojs0EPYbBRaICoLJiopf0zqcRRYWOx-bMD40CHcP6WU2MV0UROJ4b-DrRIHhAiqYj5/s1600/battery.jpeg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguUNNoYxl71AzmPWGK5D-TZ3Kv7-nZB-aOYOnd0OZMIuMV2hyphenhyphentjahjYQH08o1xWeGiSUHp3j4Jwvojs0EPYbBRaICoLJiopf0zqcRRYWOx-bMD40CHcP6WU2MV0UROJ4b-DrRIHhAiqYj5/s320/battery.jpeg" /></a></div>Batteries is dangerous if we treat them wrong.We must think safety when we are working around and with batteries. Remove all jewelry. After all you don't want to melt your watchband while you are wearing the watch.<span class="fullpost"> The hydrogen gas that batteries make when charging is very explosive. I have had 2 batteries blow up and drench me in sulfuric acid. That is no fun. This is a good time to use those safety goggles that are hanging on the wall. Sulfuric Acid eats up clothing and you may want to select Polyester clothing to wear, as it is naturally acid resistant. I just wear junk clothes, after all Polyester is so out of style. When doing electrical work on vehicles it is best to disconnect the ground cable. Just remember you are messing with corrosive acid, explosive gases and 100's amps of electrical current. </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-18962285799881537732010-04-23T06:28:00.000-07:002010-04-26T01:14:14.228-07:00Move it with a VFD - Part 2<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiiRHKMuQcirg1gaK5yFAHqGUXthUrcthyRx64VCYosbv5b6ISfNW9KvXgXPTLmAyU4728jdYqtZ8gt0kIf1hmn3Kwlnd5oLR_Vb7unDkjxUaZA4THcO8a1AAiSvxAojqy2yyQSIQyOfHZt/s1600/inverter+omron.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiiRHKMuQcirg1gaK5yFAHqGUXthUrcthyRx64VCYosbv5b6ISfNW9KvXgXPTLmAyU4728jdYqtZ8gt0kIf1hmn3Kwlnd5oLR_Vb7unDkjxUaZA4THcO8a1AAiSvxAojqy2yyQSIQyOfHZt/s320/inverter+omron.jpeg" /><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=B00006HQGY&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"><iframe src="http://rcm.amazon.com/e/cm?t=plccom-20&amp;o=1&amp;p=8&amp;l=bpl&amp;asins=B001S0KG1O&amp;fc1=000000&amp;IS2=1&amp;lt1=_blank&amp;m=amazon&amp;lc1=0000FF&amp;bc1=000000&amp;bg1=FFFFFF&amp;f=ifr" style="padding-top: 5px; width: 131px; height: 245px; padding-right: 10px;" marginwidth="0" marginheight="0" align="left" frameborder="0" scrolling="no"></iframe></a></div>As we saw last time, a VFD can often be used in a motion application where some high torque and variable speed is required. If we apply them properly they are one of the best motor controllers in industry. The key statement there is 'if we apply them properly'.<br />
<br />
To apply one correctly we really need to understand the load requirements. Basically, we need to ensure we can supply enough current for the motor so it can produce as much 'torque' as needed.<span class="fullpost">Torque may be a new term for you in the motor world. Generally, we talk about horsepower in the motor world but it relates to torque and that's what we need to discuss in the VFD world.<br />
<br />
Torque is a force that produces rotation. It is commonly measured in units of lb-ft (pound-feet). It is the force necessary to cause an object to rotate... Think of a merry-go-round (carousel ride). To get it to rotate by hand you would need to push it with a certain amount of muscle. That 'certain amount of muscle' would be the 'torque'.<br />
<br />
If you tighten a bolt with a small wrench it will be difficult. Use a bigger (i.e. longer) wrench and it will be easier to tighten. For example, to tighten the bolt to 50 lb-ft you would have to apply 50lbs of force to a 1ft long wrench. On the contrary, you would have to onlyapply 1lb of force to a 50ft long wrench to tighten it the same.<br />
<br />
Many (most?) machinery loads are constant torque loads. Conveyors,compressors, etc are some good examples. Variable torque loads are generally most pumps and fans. A VFD is usually specified for variable torque loads because they can help save energy but they are used forconstant torque loads too.<br />
<br />
Peak torque efficiency comes at a certain volts per hertz ratio. As long as our VFD stays at this ratio we can develop the rated torque.For example, let's assume we're using a 460 volt source at 60 hertz.The ratio is therefore:<br />
volts / hertz<br />
460v / 60hz<br />
7.667 v/hz<br />
<br />
As long as the ratio stays in the above proportion we can supply the rated torque. So, if the volts fall we'll need to decrease the frequency to maintain the same ratio.<br />
<br />
Horsepower is torque with the addition of time and distance. So, it's the torque generated to move something a given distance in a given period of time. It's related to torque by the formula:<br />
<br />
HP = (torque * speed) / 5252<br />
<br />
For example, if we have 30 lb-ft of torque developed in a motor rotating at 1500rpm we get:<br />
<br />
HP= (30 * 1500) / 5252<br />
HP= 45,000 / 5252<br />
HP= 8.57<br />
<br />
For reference, if we exert 1 hp we can move 550 lbs in 1 second. If we are just holding the 550 lbs still, we are not exerting any horsepower.There MUST be movement...<br />
<br />
No movement would mean no torque which would mean no horsepower. See?<br />
To specify a VFD we need to understand the torque requirements of the load. We need to consider:<br />
1- The torque required to start the motion<br />
2- The torque required to bring the load to speed in a certain period of time<br />
3- The torque required to keep the load moving<br />
4- The torque required when the motor acts like a brake to slow down the load<br />
5- And the peak torque needed by the load<br />
<br />
Most folks will use an ammeter to measure the current under all the load conditions listed above and find the peak current drawn. The VFD is then sized to the motor based on the maximum current draw at the peak torque levels plus an extra margin. Notice that the VFD is not specified based on the horsepower ratings of the motor. It's a torque thing.. </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-63631072922533990382010-04-07T20:57:00.000-07:002010-04-07T20:57:55.816-07:00Move it with a VFD - Part 1<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfy2S0XPMKH9UY_v6DNYR6HZJSblwL_MRXZDBtH4-yfAQoqa8zVVLS3aey_cuCBr-prmqGrE0ggI8WcW8IC2gTqP_v0cTmyvr_QAiOdkq1scgOd5-Jo8w5qmW1wz2kP_Q9Dae0KTbce_pZ/s1600/variable_frequency_drive-springfield_electric.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfy2S0XPMKH9UY_v6DNYR6HZJSblwL_MRXZDBtH4-yfAQoqa8zVVLS3aey_cuCBr-prmqGrE0ggI8WcW8IC2gTqP_v0cTmyvr_QAiOdkq1scgOd5-Jo8w5qmW1wz2kP_Q9Dae0KTbce_pZ/s320/variable_frequency_drive-springfield_electric.jpg" /></a></div><br />
VFD is a Variable Frequency Drive. It works with AC motors and setsthem into motion. It does so by varying the frequency of the voltage<br />
supplied to them. There you go. That's it. Simple... but now let's see<br />
some details.<br />
<br />
The VFD controls two factors of the motor... speed and torque. As you<br />
may remember from your school days, torque is a rotational force and<br />
speed is ... well... speed. Combine the 2 and you get into horsepower<br />
but that's a topic for another issue.<span class="fullpost">An induction motor (real commonly used by folks in the industrial<br />
factories of the world) would rotate at a fixed speed that is<br />
determined by the frequency of the voltage supplied to it.<br />
<br />
Alternating current (i.e. AC)applied to the motor windings in the<br />
'stator' produces a magnetic field that turns the motor shaft. We vary<br />
the speed of the motor shaft by either changing:<br />
1- The frequency of the AC applied to the windings<br />
2- The number of magnetic poles in the windings<br />
<br />
So, using a little math... and I mean a 'little math'... we can<br />
calculate the speed of the motor. Just use the formula:<br />
(120 * frequency) / number of poles = speed<br />
<br />
If we supply a 50Hz voltage to a 4 pole motor and use the formula<br />
above we can see that we will be turning the motor shaft:<br />
(120 * frequency) / number of poles = speed<br />
(120 * 50) / 4 = speed<br />
(6000) / 4 = 1500rpm (Revolutions Per Minute)<br />
<br />
So, if we examine the formula above a little closer, we can see<br />
that if we want the motor to go faster we can increase the frequency<br />
of the AC voltage applied to the windings. If, for example, we change<br />
from 50Hz to 60Hz in the example above we get:<br />
<br />
(120 * frequency) / number of poles = speed<br />
(120 * 60) / 4 = speed<br />
(7200) / 4 = 1800rpm (Revolutions Per Minute)<br />
<br />
So, now instead of turning at 1500rpm we're flying at 1800rpm.<br />
<br />
How else can we change the speed? Well as we read above we can also<br />
change the number of poles our motor has. So, if for example our<br />
motor had 8 poles in the original example we'd be moving at:<br />
(120 * frequency) / number of poles = speed<br />
(120 * 50) / 8 = speed<br />
(6000) / 8 = 750rpm (Revolutions Per Minute)<br />
<br />
So, now instead of turning at 1500rpm we're crawling at 750rpm.<br />
<br />
Trouble is, however, that the poles are a physical 'fact' of the motor<br />
so we can't just change them on the fly. We'd have to change the whole<br />
motor! What good is that if we just want the speed to vary?<br />
No good...<br />
<br />
So, you can see that the best way for us to change the speed of the<br />
motor is to 'vary the frequency' of the voltage being applied to it.<br />
Can we do that? Sure we can... with a Variable Frequency Drive (VFD)!<br />
<br />
Stay tuned as next time we'll see how the VFD actually works along<br />
with it's relationship to our powerful friend 'torque'.<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-7267798095752058452010-02-21T04:35:00.000-08:002010-02-21T04:35:00.261-08:00AS-Interface... Let the Sensors Do the Talking - Part 2<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisveSWhxz5_1D-O4riagQGQ3AJfsbt4WOpeMs351DMDkQRFf8tfcajleTY7HN_3tSPXL7xAm-H75VoO5u551UNxV7RLnWPkgOYTU649VlRc7pPa4zrEFl5ygmDFGP_m90KZ0YEFvxhhgWf/s1600-h/asi.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisveSWhxz5_1D-O4riagQGQ3AJfsbt4WOpeMs351DMDkQRFf8tfcajleTY7HN_3tSPXL7xAm-H75VoO5u551UNxV7RLnWPkgOYTU649VlRc7pPa4zrEFl5ygmDFGP_m90KZ0YEFvxhhgWf/s320/asi.png" /></a> </div><div class="separator" style="clear: both; text-align: center;"><br />
</div>Let's continue with our AS-Interface discussion. You will remember from last time that we discussed the physical hardware features. we pointed out that up to 31 sub devices can be connected to 1 main device. maximum separation between them can be up to 100 meters...<br />
that's a far distance, isn't it?<span class="fullpost"><br />
<br />
Regarding speed, it's 'reasonably' quick. Each device added to the network increases the time needed for communication. Each device requires a maximum of 150 us to talk. Plus the network needs 300 us to<br />
do some housekeeping.<br />
So, a network with the maximum 31 devices needs<br />
(31 x 150) + 300 = 4650 + 300 = 4950 us or 4.95 ms<br />
<br />
A network of only 15 devices would therefore require:<br />
(15 x 150) + 300 = 2250 + 300 = 2550 us or 2.55 ms<br />
<br />
As you can see from the above, less units mean a quicker speed. If we have 15 devices connected we can pretty much guarantee that they will be spoken to every 2.55 milliseconds. Not bad...<br />
<br />
Now let's see what actually gets sent during each message transfer and understand what goes on throughout the network.</span><br />
<span class="fullpost"><br />
Messages sent throughout the network are called telegrams. The main unit sends as many telegrams as there are connected and active sub devices on the network. So, if we have 25 devices connected the main<br />
unit will send 25 telegrams.<br />
<br />
Each sub unit will be sequentially polled by the telegrams from the main unit. The sub unit with the lowest address gets polled first and then the next higher, etc. If a sub unit becomes disconnected the main<br />
unit will notice within 1 cycle time (a maximum of 5 ms).<br />
<br />
An AS-Interface telegram sends/receives a message in both directions with the sub units. First the main unit sends a request to the subs (a write command) and then the subs reply (a read command) all within a<br />
single telegram.<br />
<br />
So, we have a main call, then a main unit pause, then a sub unit reply and a sub unit pause.<br />
<br />
A telegram will actually look like the below if we break it down into digestible pieces:<br />
<br />
St Cb A4 A3 A2 A1 A0 I4 I3 I2 I1 I0 Pb Eb<br />
<br />
St= Start Bit. This is always a 0. It's a 1 when not transmitting...<br />
<br />
Cb= Control bit. This controls if we're working with 'data/parameter access' or 'command access'. It is set to 0 for data/parameter access and 1 for command access.<br />
<br />
A4-A0= Address bits. This is the address of the sub unit we are talking with. There are 5 bits here because 11111 in binary is 31.<br />
So we can talk to any of the sub units just by setting it's address here.<br />
<br />
I3-I0= Information bits. This is the actual information that we are sending to the sub unit... depending upon the command.<br />
Pb= Parity bit. this is used for error checking. If there are an even<br />
number of 1's in the message this is a 0. if there are an odd number of 1's in the message this is a 1.<br />
<br />
Eb= End bit. This terminates the message and is always a 1.<br />
<br />
Now, let's put together a telegram where we are talking with only one sub unit. It will look like the below string of data:<br />
<br />
main unit call<br />
St Cb A4 A3 A2 A1 A0 I4 I3 I2 I1 I0 Pb Eb<br />
main unit pause<br />
3 to 10 bit times<br />
sub unit response<br />
St I3 I2 I1 I0 Pb Eb<br />
sub unit pause<br />
1 bit time<br />
<br />
Remember that the above communication happens in 1 telegram. If there were 25 sub units connected to the main unit it would still all be sent in only 1 telegram.<br />
<br />
Well, hopefully we can see how easy this network is to understand. Not much to it when we break it down into pieces and analyze the results.<br />
<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-85560802713657935622010-02-20T05:07:00.000-08:002010-04-26T09:48:32.705-07:00Transformer<div style="text-align: center;"><b>Introduction to Transformers</b></div><div style="text-align: center;"></div><br />
<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo6x3RrBdfHPtJwO1fmaHIxaR4sr7tXtx-ECrU6lq5A1Moo_pWjh_RNhy3x2E8Xq7paY01ZmBtFYbBk-rFeIEB2hZQKN4RtRIDzzVxWIN9K5qQWoapxrIoAzrZP1_TstmIZRFx7nhPuai9/s1600-h/transformer+sch.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo6x3RrBdfHPtJwO1fmaHIxaR4sr7tXtx-ECrU6lq5A1Moo_pWjh_RNhy3x2E8Xq7paY01ZmBtFYbBk-rFeIEB2hZQKN4RtRIDzzVxWIN9K5qQWoapxrIoAzrZP1_TstmIZRFx7nhPuai9/s320/transformer+sch.gif" /></a></div><br />
<br />
Two coils that have mutual inductance make up a transformer. The coil connected to the source of energy is called primary coil and the other is called secondary coil. It is useful in that the electrical energy can be transferred from one circuit to another without direct connection. It can also change the voltage level from one level to another level depending on the windings ratio of the primary and secondary coils. It can only be used with AC voltage because no voltage is induced if there is no change in magnetic field. <br />
The increase of the inductance of coils can be done by windings the coils on magnetic material like iron core. <span class="fullpost"><br />
<br />
<b>Turns Ratio, Voltage and Current</b> <br />
In a varying magnetic field, the voltage induced in a coil is proportional to the number of turns in the coil. If the coils are wound in the same field, the induced voltages will be proportional to the number of turns in each coil. <br />
<br />
<b>Vs = Vp(Ns/Np) </b><br />
<br />
where<br />
</span><br />
<ul><span class="fullpost">
<li> Vs = secondary voltage </li>
<li>Vp = primary voltage </li>
<li> Ns = number of turns on secondary </li>
<li> Np = number of turns on primary </li>
</span></ul><span class="fullpost"><br />
<br />
<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=1856175065&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>If no current is taken from the secondary(open circuit), the current that flows in the primary is called <b>magnetizing current</b> of the transformer. Typically, the transformer is designed in such a way that the power consumed by it is only to overcome the losses in the iron core and in the resistance of the wire with which the primary is wound. <br />
If the secondary is connected to the load, the current on the primary is given in the formula below assuming that the entire primary current is caused by the secondary load. <br />
Ip = Is(Ns/Np) <br />
where Ip = primary current <br />
Is = secondary current <br />
Ns = number of turns on secondary <br />
Np = number of turns on primary<br />
<br />
<b>Impedance Matching</b><br />
<b> </b> <br />
Many devices need a specific value of of load resistance for optimum operation. The impedance of an actualload that is to dissipate the power may differ from this value, so a transformer is used to change the actual load into an impedance of the desired value. This is called impedance matching. <br />
Np/Ns = Square root(Zp/Zs) where <br />
Np = number of turns on primary <br />
Ns = number of turns on secondary <br />
Zp = primary impedance required <br />
Zs = impedance load connected to the secondary <br />
<br />
Example : A transistor for audio amplifier requires a load of 200 ohms for optimum operation and is to be connected to a loudspeaker with an impedance of 4 ohms. The turn ratio, Np/Ns required will be Square root (200/4) = 7.1 i.e. the primary must have 7.1 times as many turns as the secondary. <br />
<br />
<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=plccom-20&o=1&p=8&l=bpl&asins=0132130068&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><br />
<b>Construction of Transformer</b><br />
<b> </b> <br />
Two common types of construction are SHELL type and CORE type. In the SHELL type both windings are placed on the inner leg, while in the CORE type the primary and secondary windings may be placed on separate legs. They are usually designed so that the magnetic path around the core is as short as possible.<br />
<br />
The material used for the core is usually silicon steel, built up by laminations, insulated from each other by a layer of coating. The number of turns required is inversely proportional to the cross sectional area of the core. Typically, the windings of small power transformers usually have 6-8 turns/volt on a core of 1 square inch cross section and have a magnetic path of 10-12 inches in length. A longer path or smaller cross section requires more turns/volt and vice versa. <br />
<br />
The material used for the core is usually silicon steel, built up by laminations, insulated from each other by a layer of coating. The number of turns required is inversely proportional to the cross sectional area of the core. Typically, the windings of small power transformers usually have 6-8 turns/volt on a core of 1 square inch cross section and have a magnetic path of 10-12 inches in length. A longer path or smaller cross section requires more turns/volt and vice versa. <br />
<br />
<br />
<br />
<br />
</span><br />
<div align="center"></div><span class="fullpost"></span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-86032406804600274102010-02-19T19:02:00.000-08:002010-04-26T01:15:00.852-07:00555 oscillator<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgkYuA6afLQQu_s-7j2blHDZXB6m9-PdBlUBu_GXw7kA-YRzq9jWboMoD-09aChA1wn14i2fFD2KCLSvdZTJIOwDc-MkdK4wni7B4gTxIPl3aKfhG0LOwVIKLgay-FWboHAPyNL3BGzB58/s1600-h/osilator1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgkYuA6afLQQu_s-7j2blHDZXB6m9-PdBlUBu_GXw7kA-YRzq9jWboMoD-09aChA1wn14i2fFD2KCLSvdZTJIOwDc-MkdK4wni7B4gTxIPl3aKfhG0LOwVIKLgay-FWboHAPyNL3BGzB58/s320/osilator1.gif" /></a></div><br />
This is the square wave oscillation circuit which used NE555. 555 was developed as the IC for the precision timer. It is compactness (DIP 8 pins) and it is simple composition. It is often used for the timer circuit, the oscillation circuit because of precision well the operation<span class="fullpost"><br />
</span><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcYM8Nr7DFRB0hKeVb4omMujwsKLcEVsWROtHVc2df9JilXfBKX6l7Qmzm0cTyByp8f-jkWSfmSWZ6J4zs3QUs5F5GeTXSjPGVi78I3QMvTNCoauIvIuLMQvl6j_3XJYrD6OpNt1jSTk5w/s1600-h/osilator2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcYM8Nr7DFRB0hKeVb4omMujwsKLcEVsWROtHVc2df9JilXfBKX6l7Qmzm0cTyByp8f-jkWSfmSWZ6J4zs3QUs5F5GeTXSjPGVi78I3QMvTNCoauIvIuLMQvl6j_3XJYrD6OpNt1jSTk5w/s320/osilator2.gif" /></a></div><span class="fullpost">NE555 is composed of the voltage comparators, the flip-flop and the transistor for the discharge. The composition is simple, but it is excellent one.<br />
Three resistors are connected with the inside in series and the power supply voltage(Vcc) is divided in 3. This composition is an excellent point. 1/3 with power supply voltage is applied to the positive input terminal of the comparator (COMP1) and the voltage of 2/3 is applied to the negative terminal of the comparator (COMP2). When the voltage of the trigger terminal(TRIGGER) is less than 1/3 of the power supply voltage, the S terminal of the flip-flop(FF) becomes H level and an FF is set. When the voltage of the threshold terminal(THRESHOLD) is more than 2/3 of the power supply voltage, the R terminal of the FF becomes H level and an FF is reset.</span><br />
<br />
<span style="font-size: small;"><b>The condition immediately after the turning on</b></span><br />
<span style="font-size: small;"><b> </b></span><span class="fullpost"> </span><br />
<img align="bottom" alt="" height="181" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_22.gif" width="400" /><br />
<span style="font-size: x-small;">Immediately after a power supply voltage is supplied, as for the FF, the Q becomes H and </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> becomes L condition. Because </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> is the L, TR is in the OFF condition and the electric current flows through the resistor of Ra and the Rb at the capacitor (C). Immediately after a power supply voltage is supplied, the electric charge isn't stagnant in capacitor(C). So the voltage of the X point starts from 0V. Because the X point is lower than V1 of COMP1, the S terminal of the FF becomes the H condition. With this, the Q becomes H, </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> becomes L condition but they are in the condition already. On the other hand, because the COMP2 (+) terminal is lower than V2, the output of COMP2 becomes the L and the FF is stable in this condition.</span><br />
<br />
<span style="font-size: small;"><b>Output's reverse (1)</b></span><span style="font-size: x-small;"> </span><br />
<img align="bottom" alt="" height="182" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_23.gif" width="400" /><br />
<span style="font-size: x-small;">When the voltage of the X point crosses V1 of COMP1, the output of COMP1 becomes L. However, this change doesn't change the condition of the FF. The output of COMP2 becomes the H condition when the voltage of the X point rises more and reaches V2 of COMP2. With this, the R terminal of the FF becomes H and the output state of the FF reverses. The Q becomes the L condition and </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> becomes the H condition. At this time, OUT changes into the L from H. Because </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> became the H condition, TR becomes the ON condition. Because the interface of Ra and the Rb becomes the grounded condition, the electric current which was flowing through C so far through Ra and the Rb gets not to flow through capacitor(C). The electric charge which was stagnant in capacitor(C) begins the discharge through the Rb and TR. Voltage of the X point begins to go down with this discharge. Because voltage of the X point goes down, the voltage of the COMP2 (+) terminal becomes less than V2 and the R terminal of the FF changes into the L condition from H. This change doesn't change the condition of the FF.</span><br />
<span style="font-size: x-small;">It is only in a little time that the R terminal of the FF becomes the H condition.</span><br />
<br />
<br />
<span style="font-size: small;"><b>Output's reverse (2)</b></span><br />
<br />
<img align="bottom" alt="" height="180" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_24.gif" width="400" /><br />
<span style="font-size: x-small;">Because TR becomes ON, as for the electric charge of capacitor(C), it continues the discharge and the voltage of the X point falls. When the voltage of the X point becomes equal to or less than V1 of COMP1, the output of COMP1 becomes the H condition and the S terminal of the FF becomes the H condition. This changes the Q of the FF to H and </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> changes into the L condition. Because </span><img align="bottom" alt="" height="12" src="http://www.sxlist.com/images/www/hobby_elec/gif/q.gif" width="12" /><span style="font-size: x-small;"> became the L condition, TR becomes the OFF condition and the discharge from capacitor(C) stops. The electric current flows through Ra and the Rb again in capacitor(C) and the electric charge begins to store up. When the electric charge begins to store up in capacitor(C), voltage of the X point begins to go up and the output of COMP1 becomes the L condition immediately. After that, it repeats this operation and the signal of the square wave is output.</span><br />
<br />
<span style="font-size: x-small;">When charging (accumulating the electric charge) capacitor(C), the electric current flows through Ra and the Rb and in case of the discharge (missing the electric charge), it passes only the Rb. So, </span><span style="color: red; font-size: x-small;">the time of the charging and the time of the discharge are different. </span><span style="font-size: x-small;">By making the Rb compared with Ra big, the difference of both becomes small but can not make the same at all. To make the same, it is good if Ra is 0 ohm, but in the case, Vcc is directly connected with TR and TR has broken. </span><span style="color: red; font-size: x-small;">Don't make Ra = 0 ohm absolutely. </span><span style="font-size: x-small;">If doing the ratio of Ra and the Rb by several times, in case of the practical use, there is not a problem.</span><br />
<br />
<span style="font-size: medium;">Timer IC ( 555 )</span><br />
<img align="left" alt="" height="139" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_31.gif" width="234" /><br />
<span style="font-size: x-small;">There are a lot of second sources in 555 because the circuit is simple and is with a good performance.</span><br />
<span style="font-size: x-small;">The second source is the IC to be selling by the similar function from the other manufacturer. The pin arrangement is the same and it is possible to replace.</span><br />
<span style="font-size: x-small;">There is an energy saving type of the CMOS, too</span><br />
<br />
<br />
<br />
<span style="font-size: medium;">Resistor</span><br />
<img align="left" alt="" height="137" hspace="10" src="http://www.sxlist.com/images/www/hobby_elec/picture/ckt30_47.jpg" vspace="10" width="150" /><br />
<span style="font-size: x-small;">As the resistor, I am using the type that the permission electric power is 1/8 W. More than 1/8-W resistor can be used, too. In the case, the size of the resistor becomes big. This time, 1/8-W resistors are used to make a circuit compactly.</span><span style="font-size: x-small;"> </span><span style="font-size: x-small;"> </span><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<span style="font-size: medium;">Capacitor</span><br />
<img align="left" alt="" height="135" hspace="10" src="http://www.sxlist.com/images/www/hobby_elec/picture/ckt30_48.jpg" vspace="10" width="150" /><br />
<span style="font-size: x-small;">A multilayer ceramic capacitor is used for the capacitor to decide an oscillation frequency. The capacitor with good temperature characteristic should be used for this capacitor. The capacitor with good temperature characteristic is the capacitor where little change of the value occurs even if the ambient temperature changes. The polypropylene capacitor is a capacitor with good temperature characteristic. However, the precision of the oscillator doesn't become good even if only the temperature characteristic of the capacitor is excellent.</span><br />
<br />
<br />
<br />
<br />
<span style="font-size: medium;">IC socket</span><br />
<img align="left" alt="" height="102" hspace="25" src="http://www.sxlist.com/images/www/hobby_elec/picture/ckt5_34.jpg" vspace="15" width="121" /><br />
<span style="font-size: x-small;">The IC can be put to direct to the printed board, too. This time, a socket is used.</span><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<span style="color: maroon; font-size: small;">Calculation of the frequency of 555 oscillator</span><br />
<br />
<br />
<span style="font-size: x-small;">The oscillation frequency of this oscillator is fixed by the value of capacitor (C) and resistor (Ra) and resistor (Rb).</span><br />
<span style="font-size: x-small;">Roughly oscillation frequency can be calculated by the following formula.</span><br />
<span style="font-size: x-small;">Because there is an error of the part, the oscillation frequency of the actual circuit is sometimes different from the calculated value little.</span><br />
<br />
<img alt="" height="65" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_41.gif" width="205" /><br />
<span style="font-size: x-small;">Unit f : Hz / C : Farad / Ra and Rb : ohm</span><br />
<br />
<span style="font-size: x-small;">It is possible to calculate by the following formula in the time that the output becomes H level and the time which is made an L level.</span><br />
<br />
<br />
<table><tbody>
<tr> <td><img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_gr.gif" width="11" /><span style="font-size: x-small;"> <b>The time that the output becomes H level (t</b><b><sub>H</sub></b><b>)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><img align="bottom" alt="" height="68" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_42.gif" width="262" /></td> </tr>
</tbody></table><br />
<br />
<img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_gr.gif" width="11" /><span style="font-size: x-small;"> <b>The time that the output becomes L level (t</b><b><sub>L</sub></b><b>)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><img align="bottom" alt="" height="67" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_43.gif" width="190" /></td> </tr>
</tbody></table><br />
<br />
<img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_gr.gif" width="11" /> <span style="font-size: x-small;"><b>The frequency (f)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><img align="bottom" alt="" height="68" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_44.gif" width="293" /></td> </tr>
</tbody></table></td> </tr>
</tbody></table><br />
<hr /><br />
<br />
<span style="font-size: x-small;">It is as follows when calculating at the value of the circuit this time.</span><br />
<br />
<table><tbody>
<tr> <td><img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_y.gif" width="11" /><span style="font-size: x-small;"> <b>The time that the output becomes H level (t</b><b><sub>H</sub></b><b>)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><span style="font-size: x-small;">t<sub>H</sub></span></td><td valign="top"><span style="font-size: x-small;">= 0.693 x ( Ra + Rb ) x C</span><br />
<span style="font-size: x-small;">= 0.693 x ( 5.6 x 10<sup>3</sup> + 47 x 10<sup>3</sup> ) x 0.01 x 10<sup>-6</sup></span><br />
<span style="font-size: x-small;">= 0.365 x 10<sup>-3</sup></span></td> </tr>
</tbody></table><br />
<br />
<img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_y.gif" width="11" /> <span style="font-size: x-small;"><b>The time that the output becomes L level (t</b><b><sub>L</sub></b><b>)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><span style="font-size: x-small;">t<sub>L</sub></span></td><td valign="top"><span style="font-size: x-small;">= 0.693 x Rb x C</span><br />
<span style="font-size: x-small;">= 0.693 x 47 x 10<sup>3</sup> x 0.01 x 10<sup>-6</sup></span><br />
<span style="font-size: x-small;">= 0.326 x 10<sup>-3</sup></span></td> </tr>
</tbody></table><br />
<br />
<img alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/bol_s_y.gif" width="11" /><span style="font-size: x-small;"> <b>The frequency (f)</b></span><br />
<table><tbody>
<tr> <td valign="top"><img align="bottom" alt="" height="11" src="http://www.sxlist.com/images/www/hobby_elec/gif/blank_1.gif" width="11" /></td><td valign="top"><span style="font-size: x-small;">f</span></td><td valign="top"><span style="font-size: x-small;">= 1 / ( t<sub>H</sub>+t<sub>L</sub> ) = 10<sup>3</sup> / ( 0.365 + 0.326 )</span><br />
<span style="font-size: x-small;">= 1.45 x 10<sup>3</sup></span><br />
<br />
<span style="font-size: x-small;">= 1.45 (kHz)</span></td> </tr>
</tbody></table></td> </tr>
</tbody></table><br />
<br />
<table style="width: 550px;"><tbody>
<tr> <td><div align="left"><span style="font-size: x-small;">The oscillation frequency of the made circuit was to 1,114 Hz be with the +5V power.</span><br />
<span style="font-size: x-small;">The difference with the calculated value seems to be the factor that the error of the part is big. I attempted to change 555 (different manufacturer) but the oscillation frequency was the same approximately.</span></div></td> </tr>
</tbody></table><br />
<hr /><br />
<span style="font-size: x-small;">I measured the change of the oscillation frequency by the change of the line voltage.</span><br />
<br />
<img alt="" height="268" src="http://www.sxlist.com/images/www/hobby_elec/gif/ckt5_45e.gif" width="400" /><br />
<span style="font-size: x-small;">The oscillation frequency is stable at more than +3V voltage.</span><br />
<span style="font-size: x-small;">It is the most stable in the voltage for 7V to 9V and it is the change of about ±1Hz(±0.1%).</span><span style="font-size: x-small;"> </span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-80069735066488117532010-02-19T18:07:00.000-08:002010-04-26T01:14:14.229-07:00CHARGE COUPLED BI-DIRECTIONAL POWER MOSFET RELAYThe circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply. Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line into the control circuit is a tiny 4uA.<br />
<br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM-_2wNiQ5CWTqiTXwivGs9BCG8ERXbBKOtuYKGfmmRl86aHWsmLSlLnoVCneeG3cifRFCnGonBcfrE0tPa_DQVMEMibbZlKj3q0UwJw4qZoLKyFrrplKPtd4g8D6Mt9IiJ4ICd18j1HOn/s1600-h/mosfet.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="295" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM-_2wNiQ5CWTqiTXwivGs9BCG8ERXbBKOtuYKGfmmRl86aHWsmLSlLnoVCneeG3cifRFCnGonBcfrE0tPa_DQVMEMibbZlKj3q0UwJw4qZoLKyFrrplKPtd4g8D6Mt9IiJ4ICd18j1HOn/s400/mosfet.jpg" width="400" /></a></div><span class="fullpost"><br />
Only about 1.5mA of DC is needed to turn on and off 400 watts of AC or DC power to a load.<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-49173115886303636002010-02-18T22:43:00.000-08:002010-02-18T22:43:37.612-08:00Move it with a VFD - Part 1A VFD is a Variable Frequency Drive. It works with AC motors and sets<br />
them into motion. It does so by varying the frequency of the voltage<br />
supplied to them. There you go. That's it. Simple... but now let's see<br />
some details.<span class="fullpost"><br />
<br />
The VFD controls two factors of the motor... speed and torque. As you<br />
may remember from your school days, torque is a rotational force and<br />
speed is ... well... speed. Combine the 2 and you get into horsepower<br />
but that's a topic for another issue.<br />
<br />
An induction motor (real commonly used by folks in the industrial<br />
factories of the world) would rotate at a fixed speed that is<br />
determined by the frequency of the voltage supplied to it.<br />
<br />
Alternating current (i.e. AC)applied to the motor windings in the<br />
'stator' produces a magnetic field that turns the motor shaft. We vary<br />
the speed of the motor shaft by either changing:<br />
1- The frequency of the AC applied to the windings<br />
2- The number of magnetic poles in the windings<br />
<br />
So, using a little math... and I mean a 'little math'... we can<br />
calculate the speed of the motor. Just use the formula:<br />
(120 * frequency) / number of poles = speed<br />
<br />
If we supply a 50Hz voltage to a 4 pole motor and use the formula<br />
above we can see that we will be turning the motor shaft:<br />
(120 * frequency) / number of poles = speed<br />
(120 * 50) / 4 = speed<br />
(6000) / 4 = 1500rpm (Revolutions Per Minute)<br />
<br />
So, if we examine the formula above a little closer, we can see<br />
that if we want the motor to go faster we can increase the frequency<br />
of the AC voltage applied to the windings. If, for example, we change<br />
from 50Hz to 60Hz in the example above we get:<br />
<br />
(120 * frequency) / number of poles = speed<br />
(120 * 60) / 4 = speed<br />
(7200) / 4 = 1800rpm (Revolutions Per Minute)<br />
<br />
So, now instead of turning at 1500rpm we're flying at 1800rpm.<br />
<br />
How else can we change the speed? Well as we read above we can also<br />
change the number of poles our motor has. So, if for example our<br />
motor had 8 poles in the original example we'd be moving at:<br />
(120 * frequency) / number of poles = speed<br />
(120 * 50) / 8 = speed<br />
(6000) / 8 = 750rpm (Revolutions Per Minute)<br />
<br />
So, now instead of turning at 1500rpm we're crawling at 750rpm.<br />
<br />
Trouble is, however, that the poles are a physical 'fact' of the motor<br />
so we can't just change them on the fly. We'd have to change the whole<br />
motor! What good is that if we just want the speed to vary?<br />
No good...<br />
<br />
So, you can see that the best way for us to change the speed of the<br />
motor is to 'vary the frequency' of the voltage being applied to it.<br />
Can we do that? Sure we can... with a Variable Frequency Drive (VFD)!<br />
<br />
Stay tuned as next time we'll see how the VFD actually works along<br />
with it's relationship to our powerful friend 'torque'.<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-82887630268401118022010-02-17T02:48:00.000-08:002010-02-17T02:48:00.629-08:00Creating motion with stepper motors<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAPRx9WwBTNqqaZa2R-Dmzq5UPfbdYSTmgvzNI5AiZmnKEswKc_i8KwS-W3zT-dUb6YH1OPB2cXHSYTMUueEpelwvtHmSUWOS-dnv2sJ_NBe7kSfTXVDNUZInOG84yR_ADGhX8pq0nPviv/s1600-h/block_stepper_external.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="310" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAPRx9WwBTNqqaZa2R-Dmzq5UPfbdYSTmgvzNI5AiZmnKEswKc_i8KwS-W3zT-dUb6YH1OPB2cXHSYTMUueEpelwvtHmSUWOS-dnv2sJ_NBe7kSfTXVDNUZInOG84yR_ADGhX8pq0nPviv/s320/block_stepper_external.png" width="320" /></a></div><br />
<br />
Last time we covered stepper motors and how they are used with a plc<br />
to control motion. We simply send pulses out the plc and into the<br />
stepper motor driver. The driver converts those pulses into motion<br />
through the motor. 1 pulse = 1 degree of motion, for example.<br />
<span class="fullpost"><br />
Creating motion with stepper motors is arguably the most popular form<br />
of creating motion in a controlled way. The trouble is that there is<br />
no verification that the motion actually occurred. Huh? In other words,<br />
just because we told the motor to turn 5 times doesn't necessarily<br />
mean the motor actually did what we asked it to.<br />
<br />
How can that be? If we send out enough pulses through the plc to have<br />
the motor turn 5 times we should expect the motor to do so. Right?<br />
Well, sometimes our expectations aren't always met...<br />
<br />
What would happen if there was a jam in the motion system? The motor<br />
tries to move but can't. Not good. That can (probably will...) cause a<br />
problem for our machine.<br />
<br />
Let's say we're applying labels to various sized boxes. This morning<br />
we're making product A which has a large box. Our plc program has the<br />
stepper rotate 10 times so we know the box is in the proper position<br />
and the label can be applied.<br />
<br />
Things are going great. The boxes are moving down the conveyor and the<br />
labels are being applied as expected. Time for lunch and we change our<br />
products. We now use a product that weighs twice as much as the previous<br />
one but the box size is the same. So we use the same plc program and<br />
we expect things to work out great. Correct?<br />
<br />
Not so much... the extra weight of the product is causing stalling of<br />
the stepper motor and eventually labels are being misapplied and<br />
general chaos sets in. A bad day at the office... for sure.<br />
<br />
The problem here is that the system is an 'open loop' system. There<br />
are no checks performed to verify that what we wanted done actually<br />
got done. We told the stepper motor to move but we didn't verify that<br />
it had actually done so. We have performed a 'one way' type of<br />
communication.<br />
<br />
In many simple applications or those where there are checks via<br />
sensors, for example, a one way type of communication would be fine.<br />
However, in the example above without any checks it's obviously not a<br />
good situation.<br />
<br />
In that case we need a 'two way' type of communication system. Instead<br />
of being an 'open loop' system we need to close the loop by generating<br />
some feedback about what events have occurred. But how?<br />
<br />
The answer is quite simple. We need to do an action and verify the<br />
action resulted in whatever it was we wanted. If we tell the stepper<br />
motor to turn 5 times we need to verify it did. An easy way to do this<br />
is with our old friend... the encoder. (Remember how they worked from<br />
a few issues back?)<br />
<br />
So, let's return to our great 'moving the box' application. We move<br />
light weight boxes down the conveyor by sending out 5 pulses to the<br />
stepper motor. We previously had no idea if the motor actually moved<br />
but we knew we asked it to move.<br />
<br />
If we now add an encoder to the system we can easily verify if the<br />
movement of the motor actually happened. The encoder will give back a<br />
pulse to the plc for every x-degrees the motor shaft rotates. So, if<br />
we tell the motor shaft to rotate 5 times, and each revolution is<br />
10 pulses from the encoder, the plc can look for 50 pulses. (i.e.<br />
10pulses x 5rotations = 50)<br />
<br />
If the plc 'sees' 50 pulses come from the encoder it knows the shaft<br />
has rotated the proper number of rotations. If it doesn't see that the<br />
rotation has actually happened as expected (i.e. less than 50 pulses<br />
have come back) it can react accordingly. Of course, that reaction will<br />
have to be programmed into the plc program.<br />
<br />
Now, we have added feedback to the system and closed the control loop.<br />
We therefore refer to this type of system as a 'closed loop' system.<br />
The control loop is closed because we can do something and then verify<br />
that it was actually done.<br />
<br />
A closed loop system can be created in many ways. The key point is that<br />
we need feedback on the action. How we react to the feedback is going<br />
to be dependant upon the system.<br />
<br />
Next time we'll see a motor with 'built-in' feedback to make our<br />
closed loop system of motion control 'a pleasure' to use.<br />
<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0tag:blogger.com,1999:blog-1025932121828878143.post-70437991683732896012010-02-16T04:47:00.000-08:002010-02-16T04:49:53.048-08:00AS-Interface... Let the Sensors Do the Talking<div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzkuApcB4a2xzPOjDrDioJml19gaAnwNvfCUD7h6y1yRzA5PYN_I3kesWHpAN4gt58VvWWBESgOryvH8PyQbqz_dZliSNxWRLY0qmsfusR0_a1A_n1NPdzH09_eKUJ-uVtH8_TUNl3N6HH/s1600-h/asi.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzkuApcB4a2xzPOjDrDioJml19gaAnwNvfCUD7h6y1yRzA5PYN_I3kesWHpAN4gt58VvWWBESgOryvH8PyQbqz_dZliSNxWRLY0qmsfusR0_a1A_n1NPdzH09_eKUJ-uVtH8_TUNl3N6HH/s320/asi.png" /></a></div>AS-Interface is a convenient bus for us... when we don't need to pass a lot of data back and forth. It's primary intention is for your plc to be used to with simple sensors and actuators... Hence the<br />
meaning of AS-Interface is actually 'Actuator Sensor-Interface'.<br />
<br />
<span class="fullpost"><br />
ASI came into the world back in 1994... the good old days where many (most?) plc vendors were pushing out their buses. All felt they should be world standards and (to make a long story short) to this day<br />
we have no 'world standard'. But ASI is in the mix.<br />
<br />
ASI was introduced by Siemens and based around ProfiSafe (which was in itself from Profibus DP). It is an 'open standard' which means there's an -unbiased- trade group that maintains the standard. Anyone can<br />
get (buy) a copy of the standard and develop a product based on it. IEC 62026-2 and EN 50295 are the standards numbers.<br />
<br />
It is a Main/Sub type of network meaning we can have one main unit (usually our plc) connect to many sub units. Actually, depending upon the version of ASI we're using, we can have up to 31 or 62 sub units.<br />
<br />
Generally that is large enough for all but the biggest networks. Remember, we're just connecting our plc to sensors or actuators so 62 sensors/actuators is quite large. But again, large to some is small to others...<br />
<br />
ASI is a two wire network and very simple to use. Power and data both flow over the cables. The cables are Ungrounded, Unterminated and Unshielded (That's a lot of Un's...). We can connect our network in<br />
either ring, bus, star or tree fashion.<br />
<br />
Distance is also quite good. We can go all the way out to 100 meters (over 300 ft). And if we use a repeater we can go out to about 600 meters... hopefully that's far enough for us to go. We can also connect a maximum of 124 inputs(31 subs x 4 inputs each = 124) and 124 outputs (31 subs x 4 outputs each = 124) according to the original spec (2.0) or 248 inputs (62 subs x 4 inputs each = 248) and 186<br />
outputs (62 subs x 3 outputs each = 186) according to the 2.1 spec.<br />
<br />
The cables can be connected to a power supply to transmit power to the devices on the network. Maximum power can be 8 amps at 24 VDC. Devices are simply 'tapped' into the cables at any point making installation a very simple process. The cables are typically called 'yellow cables'<br />
because they are typically... 'yellow'.<br />
<br />
We use 3 operating modes to communicate in. they are: <br />
I/O data transfer mode- The inputs and outputs of connected sub units are read from and written to in this mode. So, we transfer the status of the input/output devices to/from the plc.<br />
<br />
Analog Value transfer mode- version 2.1 allows us to work with analog data. Here, that data is transferred and processed.<br />
<br />
Command mode- Here we can send/receive various commands. Some examples are address setting of the sub units, diagnostic information reading from the subs and transferring various parameters and setting<br />
data.<br />
<br />
How do we get/send the actual data from the sub units to the main unit?<br />
Well that can be accomplished in one of two ways. The first way is arguably more popular. It is cyclic polling. This simply means that at a given point in time we have the main unit ask the subs for some specific data. In other words, the main unit polls the subs for their data. The subs get the request and send back their data.<br />
<br />
The second way is by having the sub units send their data at specific time cycles. This is simply called cyclic data reception because we receive the data during specific cycles.<br />
<br />
Maximum cycle time is ~5 ms when 31 subs are connected or 10 ms when 62 subs are connected. It's based on the fact that each cycle is 150 us and there are 2 cycle required for administration... so we get:<br />
(2x150) + (31x150) = 300 + 4650 = 4950 us or 4.95 ms.<br />
<br />
Well, hopefully that's enough of the basics to get you thinking as to whether or not this bus is right for your needs. Next time we'll see how it actually works...<br />
</span>Anonymoushttp://www.blogger.com/profile/12841840993602492568noreply@blogger.com0