Siemens SIMATIC ST-1500 Function Manual page 195

Using the module
5.2 Using the digital input module
Reaction to violation of a counting limit
The following behavior can be configured for Violation of the counter high limit in the upward
direction or the counter low limit in the downward direction (Page 83):
Reaction
Stop counting
(default)
Continue counting
Edge selection
This parameter is used to specify which edge the respective counter counts:
Edge selection
At rising edge
(default)
At falling edge
At rising and falling edge
Count direction
Use this parameter to specify the counting direction of the respective counter.
You can select from the following options:
● Up
● Down
Note
This parameter has no effect if the "Invert direction" option is selected in "Set function of DI".
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Meaning
After a counting limit is violated, the internal gate is closed (automatic
gate stop). As a result, the counting process is stopped and the
module ignores any further counting signals. The counter value is set
to the opposite counting limit. To restart counting, you must close
and reopen the software/hardware gate.
After a counting limit is violated, the counter value is set to the oppo-
site counting limit and counting continues.
Meaning
The respective counter counts all rising edges at
the digital input.
The respective counter counts all falling edges at
the digital input.
The respective counter counts all edges at the
digital input.
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG