Recommended Practices

Field Controller/RTU/PLC/IED


Definition

Controller terminology depends on the type of system they are associated with.  They provide typical processing capabilities.  Controllers, sometimes referred to as Remote Terminal Units (RTU) and Programmable Logic Controllers (PLC), are computerized control units that are typically rack or panel mounted with modular processing and interface cards.  The units are collocated with the process equipment and interface through input and output modules to the various sensors and controlled devices. Most utilize a programmable logic-based application that provides scanning and writing of data to and from the IO interface modules and communicates with the control system network via various communications methods, including serial and network communications.