The FM 355 closed-loop control module has 4 channels, and can be used universally for temperature, pressure, flow and level control.
The FM 355 controller module for SIMATIC S7-300, C7 and ET 200M (on S7-300-/S7-400 masters) can also be used in PCS7 systems.
It offers:  

• A variety of pre-programmed control structures

• A self-optimisation function for fast, simple controller optimisation and

• A backup function for problem-free operation in the event of a CPU stop/failure.

The module is available in two versions for controlling different actuators

• FM 355 C as continuous controller for the control of analog actuators

• FM 355 S as step-action or pulse-action controller for the control of actuators via digital outputs