ABB AC500-S Safety User Manual page 184

Configuration and programming
AC500-S libraries > Safety_Standard.lib
RS
Bistable function, reset dominant
Q1 = NOT RESET1 AND (SET OR Q1)
SEMA
Software semaphore. Interruptible!
BUSY is TRUE, if there was a call with CLAIM = TRUE,
but no call with RELEASE = TRUE.
CLAIM = TRUE sets BUSY = TRUE;
RELEASE = TRUE sets BUSY = FALSE;
SR
Bistable function, set dominant
Q1 = SET1 OR (NOT RESET AND Q1)
CTD
Counter down.
CV is decremented by 1 if CD has a rising edge.
Q is TRUE, if CV reached 0.
CTU
Counter up.
CV is incremented by 1 if CU has a rising edge.
Q is TRUE, if CV is reached PV.
184 3ADR025091M0208, 12, en_US 2020/06/19