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How to select a PLC in your control systems
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Date:2010-08-26 20:19:42Click:0Comment:0
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| After the planning phase of the design, the equipment can be ordered. This decision is usually based upon the required inputs, outputs and functions of the controller. The first decision is the type of controller; rack, mini, micro, or software base |
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ANSI/ISA-S5.1-1984 Instrumentation Symbols and Identification
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Date:2010-06-06 02:26:02Click:33Comment:0
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| ANSI/ISA-S5.1-1984 Instrumentation Symbols and Identification LETTER FIRST LETTER SECOND LETTER A Analysis Alarm B Burner, Combustion User's Choice C User's Choice Control D User's Choice E Voltage Sensor (Primary Element) F Flow Rate G User's Choic |
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How to design A fail-safe
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Date:2010-05-23 08:28:43Click:27Comment:0
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| All systems will fail eventually. A fail-safe design will minimize the damage to people and equipment. Consider the selection electrical connections. If wires are cut or connections fail, the equipment should still be safe. For example, if a normall |
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Wire and Cable Categories in a controls cabinet
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Date:2010-05-06 00:40:47Click:20Comment:0
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| In a controls cabinet the conductors are passed through channels or bundled. When dissimilar conductors are run side-by-side problems can arise. The basic categories of conductors are shown in See Wire and Cable Categories. In general category 1 con |
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American Wire Gage (AWG) Copper Wire Sizes
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Date:2010-04-02 21:02:27Click:15Comment:0
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| As the amount of current carried by a wire increases, it is important to use a wire with a larger cross section. A larger cross section results in a lower resistance, and less heating of the wire. The standard wire gages are listed in See American W |
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Eliminating Ground Loops
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Date:2010-03-28 08:58:56Click:21Comment:0
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| When improperly grounded a system can behave erratically or be destroyed. Ground loops are caused when too many separate connections to ground are made creating loops of wire. See Eliminating Ground Loops shows ground wires as darker lines. A ground |
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Introduction of Grounding for Safety
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Date:2010-03-19 21:03:23Click:16Comment:0
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| Grounding for Safetyshows a grounded system with a metal enclosures. The left-hand enclosure contains a transformer, and the enclosure is connected directly to ground. The wires enter and exit the enclosure through insulated strain reliefs so that th |
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grounding and its Necessary
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Date:2010-03-13 20:11:36Click:17Comment:0
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| The terms ground and common are often interchanged (I do this often), but they do mean different things. The term, ground, comes from the fact that most electrical systems find a local voltage level by placing some metal in the earth (ground). This |
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Why to do electrical design and construction
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Date:2010-01-22 20:22:42Click:29Comment:0
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| It is uncommon for engineers to build their own controller designs. For example, once the electrical designs are complete, they must be built by an electrician. Therefore, it is your responsibility to effectively communicate your design intentions to |
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Compression in internet
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Date:2009-12-23 06:01:59Click:18Comment:0
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| We can make a file smaller by compressing it (unless it is already compressed, then it gets larger) File compression can make files harder to use in Web documents, but the smaller size makes them faster to download. A good rule of thumb is that when |
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what is URLs
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Date:2009-12-23 06:00:51Click:12Comment:0
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| In HTML documents we need to refer to resources. To do this we use a label to identify the type of resource, followed by a location. Universal Resource Locators (URLs) - http:WEB_SITE_NAME - ftp:FTP_SITE_NAME - mailto:USER@MAIL_SERVER - news:NEWSGRO |
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Introduction of Phone Lines and their use in internet
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Date:2009-12-17 00:32:39Click:4Comment:0
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| The merit dialup network is a good example. It is an extension of the internet that you can reach by phone. The phone based connection is slower (about 5 MB/hour peak) There are a few main types, SLIP - most common PPP - also common ISDN - an faster |
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what is Computers addresses?
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Date:2009-12-02 07:23:07Click:22Comment:4
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| Computers are often given names, because names are easy to remember. In truth the computers are given numbers. When we ask for a computer by name, your computer must find the number. It does this using a DNS (Domain Name Server). On campus we have t |
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Introduction of Internet get to know what is internet
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Date:2009-12-02 07:20:49Click:6Comment:0
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| The Internet is just a lot of LANs and WANs connected together. If your computer is on one LAN that is connected to the Internet, you can reach computers on other LANs. The information that networks typically communicate includes, email - text files |
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