| Control loops, implemented with proportional, integral, or derivative control circuitry and simpler on/off system control points, are utilized within one of three architectures. PLCs, or Programmable Logic Controllers, are used in smaller and simpler applications. They are the oldest of the three technologies and are often programmed with ladder-logic, relay-based tools. DCSs, or Distributed Control Systems, can be used to control an entire, large scale production facility, such as a power plant or refinery. DCSs can control separate PLC systems and have other branches they simultaneously control. SCADA, or Supervisory Control and Data Acquisition, systems are used to control even larger applications, such as a series of power plants connected to a grid or multiple refineries all supplying multiple pipelines. |
