Programmable Logic Controller
PLC's have been used in Industry since the 1960's. They were designed to replace relay control systems which were prone to wear out, requiring periodic replacement. PLC's have evolved in sophistication over the decades, but they are increasingly being replaced with very small and very cheap microcontrollers that perform the same function and are easier to program via a high level computer language.
- Programmed in Ladder Logic, later generation Soft PLC's use Basic or C.
- PLC's were initially bulky due to their general purpose design.
- Standardization between manufacturers is lacking.
- Replacement of PLC programmer may be a problem due to standardization issue.
- More PLC information
An Allen Bradley PLC by Rockwell Automation
An Allen Bradley PLC conveyor belt industrial control system
PLC control of motor, solenoid and pneumatic valves