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DCS Control System. A DCS (distributed control system) is a manufacturing or process control system in which the controller elements are not centrally located, but distributed throughout the system with each sub-system controlled by one or more controllers. The entire system of controllers is connected by networks for communication and monitoring. The processor receives information from input modules and sends information to output modules. Input modules receive information from input instruments in the process and output modules transmit instructions to the output instruments in the field. Elements of a distributed control system may directly connect to equipment such as switches, pumps, and valves. DCSs control manufacturing processes that are continuous or batch-oriented, such as oil refining, petrochemicals, central station power generation, pharmaceuticals, food & beverage manufacturing, cement production, steelmaking, and papermaking.

  • SPEC #: 17651
  • Code: 17-50-01


Microprocessor Control Systems. Built around an integrated computer circuit that performs all the functions of a central processing unit, these systems are used increasingly to handle control functions previously carried out by a dedicated analogue control circuit. These control systems are programmable, so that modifications or application requirements may easily be applied without redesign. They can be programmed to make detailed calculations and statistical analyses. Data logging can be done easily, so that operation is automatic, and instrument calibration is simple.

  • SPEC #: 17652
  • Code: 17-50-02


PLC Control Systems. A programmable logic controller (PLC) is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. Unlike general-purpose computers, the PLC is designed for multiple input and outputs, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in non-volatile memory. PLCs are armored for severe condition (dust, moisture, heat, cold, etc) and have the facility for extensive input/output (I/O) arrangements. Functionality includes sequential relay control, motion control, process control, distributed control systems and networking.

  • SPEC #: 17653
  • Code: 17-50-03