Synchronization - Siemens SIMATIC ST-1500 Function Manual

2.2 Basics of counting, measuring and position input (TM Count, TM PosInput, Compact CPU)
2.2.7

Synchronization

Description
You use the "Synchronization" function to set the counter to the pre-defined start value with
an external reference signal. You can configure synchronization for the following reference
signals:
● Rising or falling edges at a digital input
● Rising edge of signal N at the encoder input
● Rising edge of signal N at the encoder input defined by the level of a digital input
Function principle
Synchronization always takes place exactly at the time of the reference signal.
Synchronization is effective regardless of the status of the internal gate.
You use the control bit (Page 185) EN_SYNC_UP to enable synchronization for counting in
an upwards direction. Use the control bit (Page 185) EN_SYNC_DN to enable
synchronization for counting down. The feedback bit (Page 188) EVENT_SYNC indicates
that synchronization has been performed. Resetting EN_SYNC_UP or EN_SYNC_DN also
resets EVENT_SYNC.
Note
The configured input filters delay the control signal of the corresponding digital input.
Synchronization has no effect on the feedback bit (Page 188) 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
35