PLC History

PLC History -

Although PLC evolved concurrently by different  by different organization, it is recognized as first being introduced by Bedford Associated in 1968. it was the product of choice to meet Gm's Hydra-matic Division's specifications. as a Replacement for traditional relay- based machine control systems. the modicon as it was called being an electronic device , also reduced wiring and Troubleshooting time. becouse it is Programmable. the PLC also allows quicker changes to the equipment's Control Behavour

Relay Based system REPLACE BY > PLC based control Systems

what do the individual work mean ?

It may make more sence to look at the work in reverse order.

Controller:- This is the keyword  A PLC monitors Various conditions, and Based on these conditions, it determines an outcome. in other word it has the ability to control the outcome based on the status of different inputs such as sensors, switches, and numeric values from analog signals, etc.

Logic:- how the PLC determines an outcome is based on the logical rules it has been taught. A simple example. it is night time AND the door is open, then turn on light.

Programmable :- The PLC is tought the rules to How it should use the Input conditions to create an outcome though its programming software. being programmable makes it versatile, so if needs or conditions change. the PLC con Be reprogrammed to meet these changes.