PLC Programming Gives Machines an Ability to Think and Behave Logically

PLC refers to a digital computer used mainly for automation in industries that use electro-mechanical equipment for their processes. Programmable Logic Controllers or PLCs are also used in amusement fair rides and can also be used to control lights. For those that deal with electro-mechanical equipment, programmable logic controller training is an invaluable investment.

The basic units of this computer are dedicated to run one program that can monitor the inputs that it gets and creates outputs that allow the program to have the desired control over the processes. PLC programming uses computer languages to give the computer the necessary instructions, the sequences of the steps, and the calculations to be made based on the inputs, and this allows the computer to automate a process or the functioning of the machine based on the resulting outputs. While the programmable controller acts as the hardware, the programming that is made into it acts as its intelligence. This allows the machine or device being controlled to have its own limited capacity brain for thinking.

Earlier, for this same control over machines, a use was made of relays which were mechanical switches that controlled the electrical source that fed power to the various functions of a machine. These switches were mechanical and hence subject to wear and tear that led them to failure. With this control, now in the realm of electronics, these failures are largely reduced and can make machines more efficient and error free. Relays also required a lot of wiring and if they were wrong or needed changes, it meant that a whole lot of rewiring would have to take place. PLC and its programming largely eliminate these physical devices through logically created steps or circuits that move the machine as directed by the program.

Most PLC programmers use Ladder Logic or Ladder Diagrams as a language for the required PLC programming. There are also other languages used by IT experts, but this method is still preferred because it follows the earlier method of schematics for relay logic, even using common electrical symbols. As a result, a program made using Ladder Diagrams will look like an electrical drawing, easily understood by electricians. This makes for easy adoption by electricians as they are comfortable with these diagrams.

To start any programming for a PLC, it is essential that the programmer acquires a thorough understanding of the process that requires automation or control. They will, of course, need to have the proper skills and knowledge of programming languages that enable them to talk to computers. While the focus of the program has to be on the functions the machine or device is expected to carry out, equal importance has also to be given to the need to startup and shutdown machines or devices. PLCs can be of many types and with different configurations, and it is important that the PLC chosen for a particular machine must take into consideration, its application, its inputs and outputs, and some spare capacity that can be used in case you need to augment the PLC functions at a later date.

It is important that before any PLC is programmed, all the persons involved with the machine, its operations, and the required degree of control and automation are part of any discussions. In many cases, these discussions can lead to changes required to be made to machines, so that they are mechanically able to perform the functions that are now required of them.

PLC programming allows machines or processes to have their own capacity for thinking that is limited to the work or steps that are being carried out by that machine or process. Many PLC programs will also include diagnosing software that gives the operator the reason for any malfunction and the required steps to correct it.

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Tom Archibeque
Tom Archibeque
Tom Archibeque is the instructor for Control Logic Training. He currently provides PLC training to maintenance and engineering personnel at Control Logic Training.