The Industrial Raspberry Pi Forum

Hi,

I have been trying to use the on-board relay of the RevPi Connect+ to open the circuit of an emergency stop chain. When I activate the RevPiLED bit 6 I can hear the relay Latching. The problem is that I get always continuity between the relay terminals. It doesn't matter if the bit is on or off. I opened the RevPi and I measure the voltage across pin 1 and 12 of the EE2-5NU relay and I have 0 V even it the bit is True.

What I think it is happening is that the relay is just being activated by a Pulse and not a constant 5 V. Is that the normal operation? How can I get the relay to stay in the energized position?

Best regards

Hi albertobueno, the relay is in the normally closed state. I have taken the information from the RevPi Connect circuit diagram, see here:
https://revolutionpi.com/tutorials/down ... haltplaene
I can't imagine what you describe, that it appears that there is only one pulse because it is a mundane relay.
Here is the tutorial for the relay, and it should be possible to open and close the contact:
https://revolutionpi.com/tutorials/uebe ... kt-connect

The states are also shown here in the tutorial on the status bytes 0=Relay closed 1=Relay open
The relay may be defective. This is because it is a mechanical component that wears out due to the number of switching operations.
I had the experience myself once and switched the relay on and off on the RevPi Connect in an endurance test over the weekend.
When I examined the test results on Monday, I noticed that the relay was no longer working.

Hi Dirk,

Thanks for the reply. I am 100% the relay is working and I have already connected an oscilloscope to the relay coil and it receives a 5 V pulse when the bit is activated. I guess there is something in the software/hardware besides the relay that is malfunctioning. I haven't updated the Connect+ since around 2020.

Form the moment I am using a DO from another module.

Best regards

Hi albertobueno, So it seems strange to me and my recommendation is that you update your system that has not been updated since 2020 using the following checklist created with great attention to detail:
https://kunbus-gmbh.atlassian.net/servi ... /836468748

Hi Dirk,

Yes, updating the image to the latest resolved the issue.

Thanks!

Hi albertobueno, thank you very much for your positive feedback.