7 - Programmable Control Subsystem

Abstract

Programmable control subsystem, also known as soft-wired control subsystem, plays a vital role in making automation systems more compact, power-efficient, reliable, flexible, communicable, and self-supervisable. This control subsystem has all the advantages of a solid state control subsystem, as the processor-based systems are also solid state. In addition, they have the advantages of modularity, extendibility, and flexibility for strategy modification or extension (soft-wired automation strategy). Since they are soft-wired, the connections are established through software. During information acquisition, electronic inputs to the control subsystem are converted by the programmable control subsystem into computer data or simply data for further processing within the controller. Programmable control subsystem comprises power supply subsystem consisting of a power supply module, processor subsystem consisting of processor and memory modules, and I/O subsystem consisting of various types of I/O modules. All these modules are physically integrated over a bus, which provides a path for communication and data exchange between the processor and other functional modules. The controller, being processor-based, can easily be programmed to work as a multi-input/multi-output (MIMO) control subsystem since the data related to all the loops is available in the common memory for use by any loop. Furthermore, the fast processor in the controller can handle many loops simultaneously while still meeting the time requirements.