Temperature and process controllers are generally divided into one or two categories: single-loop and multi-loop.
When should a single-loop regulator be used?
If a system requires a single control loop or discrete devices, then a single loop controller can be used to control a heat engine or process. These instruments can be very basic profiling devices - manually changing the set point or the most sophisticated devices that can perform multiple set point changes over a specified period.
Single-loop controllers are also often referred to as front panel controllers (FTP). These controllers provide a clear display on the front of the panel. The operator or engineer (end-user) can use this screen to configure the controller and make subsequent program changes.