PLUS+1 Hardware > Controllers

SC050-020 Digital Out Errors


I have a safety controller using a digital output (C1p33) to power a Danfoss Series 7 analog valve that will stop working and requires power cycle to reset.
Looking at the output pin in service tool, DigOut variable shows true but the DigFeedBack shows false and Status shows Bit8 as true.

After a few cycles of the digital output turning off and on, this error will pop up.

To fix the error I found a topic on this form

In the topic Tor shows that momentarily disabling the safety monitor for the pin can fix the issue by setting C1p33 "DisableOutputSafetyMonitoring" variable to true. Their method shows setting the DigOut transition to false to trigger a delayed off, turning on the variable for a few seconds.

My testing found that this reduces the chance of the error but does not fix the issue. For production I set "DisableOutputSafetyMonitoring" variable to true permanently and this prevented the error from stopping the pin function. I did this for all of the digital outs on the safety controller because I notices that some pins were more sensitive than others to the error.

I had seen this somewhere else and though I would start a new thread highlighting what worked for me.

Hi all,

I have the same problem with SC024. I use C2P07 as Dig output to power Coil.
After a few cycles of the digital output turning off and on, the output stooped working and requires power cycle to reset controller.

I want to use the solution proposed here in this topic but I can not found  "DisableOutputSafetyMonitoring".

With best regards

Hi Scott,

Good idea to start a new thread, I have the same issue but with different hardware SC050-122. For me the fix from Tor is also not working only reducing. I also noticed that some pins are more sensitive to produce a status bit 8 error than others.
I will try your solution as well, but this isn't a fix which is going to work for me in order to be compliant with the requirements from the functional safety standard. I'm also in contact with Danfoss to solve this issue. I will post my findings as well.


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