Programmable Logic Controllers (PLCs) are the most common computing basis for automated process control systems on the factory floor. Such systems drive all handling parts like sorting, conveying, stocking, picking, packaging etc.

A PLC is a small device used for automation of real-world processes, such as control of machinery on factory assembly lines. The main difference to other computers are the special I/O arrangements. These connect the PLC to sensors and actuators. PLCs read limit switches, dual-level devices, temperature indicators and the positions of complex positioning systems. Some even use machine vision. On the actuator side, PLCs drive any kind of electric motor, pneumatic or hydraulic cylinders or diaphragms, magnetic relays or solenoids.

In this application a 6U VMEbus single-board computer based on the PowerPC® MPC 8245 acts as the computing core of a PLC. It offers DRAM, Flash and CompactFlash® memory, dual Fast Ethernet, 4 COMs, USB, IDE and keyboard/mouse interfaces as well as an optional onboard hard disk. The CPU board has room for three M-Modules™ which offer all kinds of real-world I/O functions.

The VME PLC is connected to an Oracle data base server via Ethernet TCP/IP. It can further be used in a Human-Machine Interface connected to a bar code reader, radio label reader or to weighing machines. Or it can be used to drive auto-guided (filo-guided, fero-guided, opto-guided) vehicles that carry loads from several kilos to many tons. Depending on the project, an SSI (Serial Synchronous Interface) M-Module™ for connection of up to four sensors to optically isolated SSI outputs is used. Serial synchronous interfaces are commonly used for many kinds of sensors such as rotary encoders. Another M-Module™ provides the interface to the ASI fieldbus network.