I have been asked about how to connect safety relay for several times, most of the time I gave only rough idea because I've never looked into its datasheet. Just yesterday, a member of this forum PM me and asked about making connection to Pheonix Contact safety relay model PSR-SCP- 24UC/ESA2/4X1/1X2/B.

In this connection, the OSSD output is used to turn on Pheonix safety relay. If any of UB1 safety inputs disengage, then OSSD turn Pheonix safety relay off. Since, the Pheonix relay is intelligent relay has capacitors and electronic components inside, there would be a small discharge time or delay time before it totally turn off.

Pheonix relay should start automatically after Reset button is pressed.