Allen Bradley Guardmaster safety relay Low Voltage on S12 and S22

[Baker in Virginia]

Good Evening ,

I have a Guardmaster Safety Relay I have 14 vdc on S12 (Safety Input for IN1 Channel 1) and on S22 (Safety Input for IN1 Channel 2) I have 18 vdc. On S32 ( Safety Input for IN2 Channel 1 ) I have 23.51 vdc . On S42 ( Safety Input for IN2 Channel 2) I have 23.51 vdc. I am having a difficult time resetting this safety relay. Do these safety relays have a internal power supply ? Do these voltages concern you any ? I believe it is a 440R-D22R2.

Thanks so much in advance ,

 

[Ken Roach]

The lower apparent voltages are because you're measuring the pulse-tested sources: S11 and S21 send out 24V pulses at different patterns and rates so they can be differentiated. An ordinary digital meter will measure these as 14V and 18V (respectively) because that's what they average out to.

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/1040292


You're measuring those voltages on S12 and S22, which makes sense because those are the signals from the pulsed sources, having traveled through the e-stop relay contact or whatever you're using as a sensor. S12 and S22 are Channel 1 and Channel 2 of Safety Input 1.

But the fact that you are seeing a more nominal 24 V on the Channel 1 and Channel 2 inputs for Safety Input 2 suggests that those circuits aren't sourced from the pulsed S11 and S21 channels or from a OSSD style safety pulsed output.

What's the difference in the devices that are connected to Input 1 and Input 2 ?

Was this relay working correctly at some point ?