The input MA_I allows the SERVO function block to adjust to the controller’s operating mode. To do this it must be attached to the output MA_O of the controller or the corresponding MS function block.

The function block SERVO only rereads the control output if this has been updated (i.e. whenever SEN is set to 1).

The user can modify the control output here at any time. In order that a new value can be included as soon as possible, the function block reads the control output at every cycle.

In this operating mode the user can manually modify variables connected to the OUT output of a controller or a MS block. If no positional feedback is used this variable can adopt the end position (100% or 0%) even if the actuator has not reached either of its end positions. It is still possible to modify the output modification OUTD manually by setting the output OUT of the function block MS to more than 100% (or to less than 0%). The value inputted for OUT is used for the calculation of OUTD before it is limited again.