A brief history of PLC

Disclosure: In any review for a product or service, products or compensation may have been provided to me to help facilitate my review. All opinions are my own and honest. I am disclosing this in accordance with FTC Guidelines. Please see “Disclose” and "Terms of Use" tabs for more information.

Many engineering students or even regular people ask themselves what is a PLC. In this article we will try to answer this question, providing some information about the history of plc.


A programmable logic controller is a computer device used by an industrial control system. It can be used wherever control devices are needed because PLC offers a flexible way to soften components together – this means that the information can be transmitted electronically as opposed to hard-working components but are saved. The way the PLC works is to rely on internal mechanisms, meaning that to create a PLC control circuit, one needs to write a program according to the system’s requirements. Then this program is applied to chips.

PLC in history 

When it comes to automation, we have to look back to the late 1960s and consider the importance of automated manufacturing processes as a logical controller (PLC) in the industry. In 1968 when General Motors’ automated transmission division proposed electronic alternatives to the rigid wired relay system, the relay had to be tightened in a certain order for the machine to run properly. If there is a problem, the whole thing stops working. Troubleshooting is not a quick process.

The solution to all this came in 1968, and that was PLC programming. Computer control was beginning to gain some attention at the time, and the winning proposal for the General Motors issue came from Bedford Associates, whose team consisted of two people. It became known as “PLC”. 

The PLC kept getting ready. Previously PLC relays were capable of working with coils, timers, counters, input and output signals. Evolution included analog input signals, analog output signals, floating-point math, improved timers and counters, math functions, drum sequencers, and single shots. As their functionality increased, so did the number of PLC as well as programming devices. It is also pertinent to note that the automotive industry is still one of the biggest customers of PLC, considering that it is the industry is where PLC started. However, given their functionality, PLCs can be used in many other industries. For an example, PLC can be used when it comes to automatic wastewater systems.

As long as the method is rational, PLC can take care of many functions, and is capable of working on the whole circuit control, according to the contents of the written program. Even though PLCs have been around for a while and there are other ways to do things, PLCs have laid their foundations for decades and are still popular. They can be very flexible when it comes to writing programs, they are compact, economical, and very reliable. There are no (or very few) mechanical failures or program accidents. There are many devices in the market now, most of which are manufactured by foreign companies.

Speak Your Mind