Siemens SIMATIC ST-1500 Function Manual page 32

2.2 Basics of counting, measuring and position input (TM Count, TM PosInput, Compact CPU)
The figure below shows another example of the Capture function with the following
configuration:
● Start value = 0
● Capture event upon rising edge at configured digital input
● Set counter to start value at gate start
● Reset counter value to start value after Capture event and continue counting.
The control bit (Page 185) EN_CAPTURE is used to enable the Capture function. The
feedback bit (Page 188) EVENT_CAP indicates that a counter value has been saved as a
Capture in the feedback interface. If you reset EN_CAPTURE, EVENT_CAP is also reset.
The status of a digital input is indicated by the respective feedback bit (Page 188) STS_DIm .
The figure below shows an example of the EN_CAPTURE and EVENT_CAP bits with use of
the Capture function by the rising edge at a digital input:
Note
The configured input filters delay the control signal of the corresponding digital input.
The Capture function has no effect on the feedback bit STS_CNT and the LEDs UP and DN.
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG
The basics of counting, measurement and position detection
31