A Control Loop is a group of Function Blocks (FBs) that execute at a specified rate within a fieldbus device or distributed across the fieldbus network.
A combination of two or more instruments or control functions arranged so that signals pass from one to another for the purpose of measurement and/or control of a process variable. See closed loop and open loop.
The path through the control system between the sensor, which measures a process variable, and the controller, which controls or adjusts the process variable.