Siemens SIMATIC FM 351 Manual page 108

Modes and Jobs
Remaining Distance
The remaining distance is the signed difference between the target (incremental
dimension) and actual value.
On a rotary axis, the displayed remaining distance cannot be used.
Terminating an Incremental Approach
The "incremental approach" mode is terminated when the FM 351 receives a
STOP signal (STOP=1).
After the approach has been terminated, a remaining distance still remains.
The remaining distance of a "relative incremental approach" can be traveled, when
The operating mode is unchanged, and
The incremental dimension number is unchanged,
The direction is unchanged and
The remaining distance is greater than the set switch-off difference.
You travel the remaining distance by starting the "relative incremental approach"
unchanged.
Aborting an Incremental Approach
The "incremental approach" mode is aborted when the "drive enable" signal is
cleared (DRV_EN=0).
Delete Remaining Distance
With the "delete remaining distance" job, you delete the current remaining
distance.
If you start a different mode or start the mode in a different direction, you also
delete the current remaining distance.
Data Used in the Channel DB
Address Name
35.2 DELDIST_EN
9-22
Type Initial Value
BOOL FALSE 1 = delete remaining distance
Comment
FM 351 Positioning Module
C79000-G7076-C351-02