PLC or programmable logic controller is a reliable computer monitors automation. It is the best way to gain quick control processes in real time. It is the most common hardware in industrial manufacturing arena due to its technology which is convenient and less time consuming than other controllers.
The idea of PLC technology is changing as time goes by, so today, you can find various, high-end models with touchscreen and intuitive software. Still, the most common programming language is rslogix 500, and throughout the article, we will explain you more about it:
But let’s start from the beginning:
What Is a PLC?
According to NEMA (The National Electrical Manufacturers Association) PLC is a digitally operating electronic apparatus that features internal storage of instruction in programmable memory so that it can implement specific functions such as timing, sequencing, logic, arithmetic and counting with the idea to control digital and analog input and output modules as well as other machine processes.
Briefly speaking, PLC is durable and solid industrial control devices that use signals from other devices such as switches and sensors and implements them through ladder diagram and provides outputs for the control of the automated processes and accessories such as motor starters and relays.
With it, you will get a programmable electronic interface that will allow you to execute, manipulate and monitor the state of communication systems in the real time. Everything operates on the basis of programmable data and basic microprocessor systems.
A programmable logic controller has the ability to receive and to transmit various types of electronic signals, and it can monitor and control any kind of electrical or mechanical system. That will provide you outstanding flexibility when it comes to communication with machines, computers, and other peripheral devices or systems. Click here if you want to learn more on programmable logic controllers.
The usual program is ladder logic which is perfect because it works on visual and not text perspective, which is an excellent choice for the industrial environment.
What It Looks Like?
You will be able to get PLCs in different sizes. Have in mind that in general, the size and space that PLC will occupy is in relations with input/output requirements and user systems as well as the manufacturer’s packaging and designing capabilities.
It can be enclosed or open type, and individual modules tend to plug into the back of the place. The electronic components come on PCBs or printed circuit boards, and they are within the module.
How It All Started?
The first programmable logic controller entered the market in the late ‘60s, and the idea was to control the automatic processes.
Manufacturers required faster and better control relays that would fit into the less space and with the idea to reduce the hassle of program inflexibility such as drum programmers, stepping switches and hard-wired relays, and that is when PLC started.
Even though PLC in comparison with PC have been interchanged in speech, the main difference between them is that PC could control functions only for a specific program, which means that it contained limited skills and it was a hassle to reprogram it completely.
On the other hand, using PLC required for programmers to write the software logic and you will be able to change it based on the new demands you have and want to control. Therefore, PLC is a more flexible solution than PC, and it can quickly adapt to changes in how it monitors and process application requirements.
How Does It Work?
If you want to learn how PLC works, it is vital to understand its CPU, or central processing unit scan sequence. The specific methods are the same for all controllers, however, as soon as you add specific hardware modules into the system, you will be able to get additional features.
First, you have to scan the input and output models by using the ladder logic software based on the programming and the industry you’re working. As soon as you power it up, the processor will scan the input module and transfer the data into the register or image table.
Data from the image table will be transferred to the output module. The next step is that the software program has to be scanned and each statement researched and checked so that you can see whether all conditions are perfect.
If everything is okay, the processor will write a digit 1 into the output image, and that will energize the peripheral device. If conditions are not met, the processor will write 0 into the output image table, and the device will remain de-energized.
A PLC will interface various types of external electronic and electrical signals. These signals could be DC or AC voltages or currents. They tend to range between four and twenty mA or zero to 120 VAC.
Check this link: https://www.wikihow.com/Set-Up-RSlogix-5000 to learn how to set up Rslogix.
These signals will remain as input /output points that you should check up. The total is I/O capability, and from an electronic perspective, this number represents and is based on scores that CPU can scan or look at at the specific amount of time.
This particular characteristic is called scan time. It is vital to have sufficient input/output capability in the PLC system. The more you have it, the faster the process will be, and it will become more convenient to write existing input/output points into the software.
In case that you have spare points, you do not have to worry, because you can program software to ignore them and they won’t affect the scan time.
As you can see from everything that we’ve mentioned above, the idea of PLC is not that complicated, even though you haven’t seen it before.
We cannot imagine the automated manufacturing facility without an appropriate programmable logic controller that will meet the demands and help you control everything.
It is a much better choice than implementing industrial PC because it is durable, sturdier and it can withstand harsh conditions, which means that you can use it in almost any manufacturing facility without any additional problem.