A PLC is a digital computer used for automation of typically industrial electromechanical processes, such as control of machinery on factory assembly lines. PLCs are designed for multiple analogue and digital inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. A PLC is an example of a hard real-time system since output results must be produced in response to input conditions.

    Various types:

S7

Siemens S5 and S7 – The S5 product line is usually programmed with a PC based software programming tool called Step 5. Step 5 is used for programming, testing, and commissioning, and for documentation of programs for S5 PLCs. The S5 is an obsolete PLC which was replaced by the S7 range.
The S7 is programmed with Step 7.

PLC_5

Allen Bradley PLC5 and SLC – The PLC-5 processor module provides a proven approach for industrial control. PLC-5 processors are high-speed, single-slot processors used for control and information processing. They are designed for larger sequential and regulatory control applications with specialized I/O requirements and/or the need to coordinate with other processors and devices.
The SLC500 range of processors were developed for smaller control systems

MicroLigix

MicroLogix – This PLC offers 5 levels of control and a wide variety of functionality to suit most applications; along with similar functionality as traditional PLCs.

CompactLogix

CompactLogix – This version offers a high functionality in an economical platform and specialty modules to cover a wide range of applications.

ControlLogix

ControlLogix – Provides high speed, high-performance and multi-disciplined application control. This PLC also includes scalable network communications.
http://ab.rockwellautomation.com/Programmable-Controllers/MicroLogix-Systems

We also work on the following PLC’s which are obsolete and generally need replacing.
GEM80– These PLC’s were developed by GEC and mainly used in the Steel industry.

Alspa– The Alspa range were supplied by GEC as a less powerful PLC

Modicon Quantum