Siemens SIMATIC ST-1500 Function Manual page 52

2.2 Basics of counting, measuring and position input (TM Count, TM PosInput, Compact CPU)
Setting by the user program up to comparison value
You can set each digital output to 1 (edge) by setting the control bit (Page 185) SET_DQm.
The respective digital output is set to 0 by any of the following events:
● Matching of the position value and the comparison value or crossing of the comparison
value in the configured direction of the comparison event
● Resetting of the SET_DQm control bit.
The figure below shows an example of the comparison event when counting up:
You can disable the digital output before the position value corresponds to or exceeds the
comparison value by setting the control bit SET_DQm to 0.
Note
If the comparison value is reached or exceeded in the assigned direction, feedback bit
EVENT_CMPm is set independently of the status of control bit SET_DQm.
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG
The basics of counting, measurement and position detection
51