Siemens SIMATIC ST-1500 Function Manual page 42

2.2 Basics of counting, measuring and position input (TM Count, TM PosInput, Compact CPU)
Periodic synchronization
The figure below shows an example for periodic synchronization at signal N:
As long as synchronization for counting in an upwards direction is enabled, the counter is
synchronized at each signal N.
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG
The basics of counting, measurement and position detection
41