Siemens SIMATIC FM 351 Manual page 105

Absolute Incremental Approach
7. Set the control signal:
Linear axis:
– START: The only possible direction
is determined by the target and the
current actual value.
Rotary axis
– START: The target is approached
along the shortest path.
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
8. Call FC ABS_CTRL.
Sequence of the "Incremental Approach" Mode with Incr. Dim. Number 255
Absolute Incremental Approach
1. Set the control signal for the "absolute
incremental approach" mode
(MODE_IN=5).
2. Set the control signal for drive enable (DRV_EN=1).
3. Set the function switch for "do not evaluate enable input" (EI_OFF=1) or wire up the
enable input for the relevant channel.
4. Enter the incremental dimension number (MODE_TYPE=255).
5. Enter the incremental dimension for incremental dimension number 255 (TRG255).
6. Enter the value of the switchover difference for incremental dimension number 255
(CHGDIF255).
7. Enter the value of the switch-off difference for incremental dimension number 255
(CUTDIF255).
8. Set the trigger bit for writing the incremental dimension, switch-off and switchover
difference (TRG255_EN=1).
9. Set the control signal:
Linear axis:
– START: The only possible direction
is determined by the target and the
current actual value.
Rotary axis
– START: The target is approached
along the shortest path.
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
10. Call FC ABS_CTRL.
FM 351 Positioning Module
C79000-G7076-C351-02
Relative Incremental Approach
7. Set the control signal:
Linear axis:
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
Rotary axis
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
Relative Incremental Approach
Incremental Dimension Number 255
1. Set the control signal for the "relative
incremental approach" mode
(MODE_IN=4).
9. Set the control signal:
Linear axis:
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
Rotary axis
– DIR_P; Start in plus direction
– DIR_M; Start in minus direction
Modes and Jobs
9-19