Siemens SIMATIC ET 200SP - Capture with SSI Absolute Encoder

The basics of counting, measurement and position detection
2.2 Basics of counting, measuring and position input (TM Count, TM PosInput, Compact CPU)
Counting, measurement and position detection
Function Manual, 12/2017, A5E32009889-AG
33
2.2.6.2
Capture with SSI absolute encoder
Description
The "Capture" function is used to save the current position value using an external reference
signal. You can configure the Capture function for the following reference signals:
● Rising or falling edge at a digital input
● Rising and falling edge at a digital input
Function principle
At the time of each edge, the position value of the last valid SSI frame is stored in the
Capture value.
The figure below shows an example of the Capture event by a rising edge at the configured
digital input:
The control bit (Page 185) EN_CAPTURE is used to enable the Capture function. The
feedback bit (Page 188) EVENT_CAP indicates that a position value has been saved as
Capture value 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 .