AB 5069-OBV8S Safety Output Relay

[beemboss]

Hi,
I am using AB 5069-L306ERS2 CPU. My system should achieve SIL-2. I have safety door switches connected to AB 5069-IB8S module, and I want to send a dry contact interlock signal to a high voltage power supply if any of these switches is activated. My question is how to connect the output signal from the AB 5069-OBV8S module to the power supply in order to make it SIL-2. Should I use 2 output channels and connect them to 2 different relays (relays contacts are connected in series)? Should I use regular relays or safety relays in this case, and what safety relays should I select?
Thanks.

 

[ASF]

Very general answer: with the OBV8S you can connect two relays in parallel to the Out+ and Out-, and since both the Out+ and Out- are switched by the module, it has the same integrity as having two separate 24V outputs with a permanently connected 0V. Generally you would use safety relays in safety applications, but ultimately only a full system validation encompassing the whole design and all components will confirm whether your system meets any particular safety threshold. We typically don't use SIL in Australia, only PL, and again in broad terms, you will more easily reach a higher PL rating with safety relays than with non-safety relays.