ABB AC500-S Safety User Manual page 89

Fig. 38: 2 channel equivalent mode implemented in DX581-S
2020/06/19
DANGER!
After discrepancy time error, the relevant channels are passivated. As soon as a
valid sensor state is observed (equivalent or antivalent, depending on the
selected mode), reintegration request status bit for the given channel becomes
TRUE. You can acknowledge an error using acknowledge reintegration com-
mand bit for the given channel. This can directly lead to the machine start,
because both TRUE - TRUE and FALSE - FALSE are valid states for equiva-
lence and TRUE - FALSE and FALSE - TRUE are valid states for antivalence.
Make sure that such behavior is acceptable in your safety application. If no,
then you can use either included PLCopen Safety POUs for 2 channel evalua-
tion in your safety program or write your own POUs for 2 channel evaluation on
the safety CPU.
3ADR025091M0208, 12, en_US
DX581-S safety digital input/output module > Functionality
AC500-S safety modules
89