Function unit for controlling a single (DIN 19 237).
The single control for an actuator is the smallest (and lowest) function unit within the control for a process. It controls a single control element or actuator. It is actuated by hand or by a higher level function unit.
The single control for an actuator includes as a minimum a monitoring section for signalling the operating state of the device controlled (steady-state, transition, malfunction among others) (Figure E 15).
Figure E 15: Single control for an actuator