Siemens SIMATIC ST-1500 Function Manual page 125

Using the High_Speed_Counter technology object
3.6 Programming the High_Speed_Counter
Changing the count direction
The count direction can only be changed by the user program if "Pulse (A)" is configured as
the signal type. In all other cases, the count direction is determined by the input signals of
the technology module. The count direction is controlled by the static tag NewDirection:
● +1: Upward count direction
● -1: Downward count direction
To execute the change command, you need to set the tag SetNewDirection = TRUE.
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Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG