Siemens simatic et 200s Operating Instructions Manual page 342

1PosUniversal/Digital
7.6 Functions of the 1PosU
Rotary axis
You determine the direction in which the destination is approached by selecting the
directional enable (DIR_M, DIR_P):
Control bits DIR_P and DIR_M
DIR_P = 1
DIR_M = 0
DIR_P = 0
DIR_M = 1
DIR_P = 1
DIR_M = 1
Figure 7-16
342
Execution of Absolute Positioning
Direction
The destination is approached in the plus direction.
The destination is approached in the minus direction.
The destination is approached by the shortest route. The
1PosU determines the direction the destination is to be
approached from. If the resulting distance to be traveled
is smaller than the switch-off difference, no run is started
(POS_DONE = 1).
Operating Instructions, 05/2007, A5E00124871-04
ET 200S Positioning