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A brief history of Programmable Logic Controllers

Although programmable logic controllers are all around us, in many technical items we use today, they were first developed to increase efficiency in the automotive industry.  Originally cars were constructed using cumbersome relay system connecting cam drivers, drum sequencers and closed loop controllers.  This was time consuming and required frequent reprogramming.

Project Number 084

In 1968 GM Hydromatic requested that Bedford Associates in Massachusetts develop one of the earliest programmable logic controllers.  Bedford Associates were willing to undertake the project and the first programmable logic controller was called project 084 because it was their 84th project.  This inspired Bedford Associates to start a new company that worked on specifically designing, constructing and selling the product, which was to be known as Modicon.

Modular Digital Controller (Modicon)

The,’Father ‘, of the Programmable logic controller, Dick Morely , worked on the Modicon project which was eventually sold to Gould Electronics in 1977. The brand was later sold to AEG in Germany until it was purchased by French Schneider Electric, who is still the current owner.  The automotive industry still uses programmable logic controllers more than any other industry.

 Ladder Logic

The original programmable logic controllers were produced to replace complicated relay systems that required a lot of technical input by an engineer.  Ladder logic was developed so that the engineer could apply his knowledge of relay systems to a simplified programming language.  This was an attempt to decrease the amount of training required for existing technicians to get up to date with the new technology.

Technology Today

Programmable logic controllers are used all around us today and vary in size and complexity.  The language used to input the information is increasingly more complex because they are undertaking complex procedures. The automotive industry is still the most prolific user of programmable logic controllers in production and in the interior of our cars.  Cars can be tuned to perform perfectly in a variety of conditions by attaching a laptop with PLC software to the car’s ECU, which is the main brain of the car.

Breaking the 200 mile an Hour Speed Record on ICE

In 2007 four times world rally champion Juha Kankkunen broke the world ice speed record on the frozen sea off the East Coast of Finland.  The successful record attempt was achieved in a Bentley Continental GE that had an engineer using a lap top programmed with software that enabled the car’s ECU or main brain to be tweaked occasionally to improve the performance of the car.  There was very little intervention by the engineer because the car had already been programmed efficiently in the first place.