RTD Module Failure question

[ceilingwalker]

Good day all, I changed the configuration of an RTD Module and when I resumed the program the system had a fault and shut-down. The module is a 1746-NR4 and it is connected to a 5/03 processor. When I went to the Processor Status Page the error description displayed "Module in slot 11 has a general alarm bit set to 1" (not verbatim). I shut the entire plc down and re-stored it again, four times. Each time I would return power, would immediately go into fault mode and shut all of my outputs down. The only remedy I could find was to remove the contact blocks from each of the modules, turn the system back on, then (with modules powered) re-install the contact blocks. After doing that, the system was fine and error-free. My question is, why did it require me to disconnect the field wiring and re-install, with the power on, to clear the error and resume scanning the program. Thank you.

 

[Ron Beaufort]

have you taken a look at Chapter 7 (Module Diagnostics and Troubleshooting) of the module's user manual? ... what were the 5 LEDs on the front of the module doing when you had the error? ... what status were the error bits in when you had the error? ...

just guessing - maybe the new configuration you tried didn't match the actual hardware setup - and the module caused a fault as a result ... you might also trying to just "enable" one of RTD channels at a time to possibly tell which channel was causing the error ...

suggestion: if the problem pops up again, write down the Error Code from word S:6 ... we might be able to research that code and tell more about your problem ...

 

[ceilingwalker]

Thank you Ron for the info. I wrote down the alarm it is: "Specialty I/O module in slot 11 has generated a generic fault. The card fault bit is set to (1) in the modules status bit". Don't know if that's enough but it's all I have.

 

[ceilingwalker]

Is there a place where a history of alarms is? I have looked and can't find it, if there is one.

 

[Ron Beaufort]

no history ... once they're cleared, they're gone ...

 

[ceilingwalker]

Ok Ron, it did it again. Here is what I have:

Major Error Halt S:1/13=1
Major Error S:54=B58h
Last Major Error S54=B58h

Debug tab
Fault/Power down
Rung#S:20=11
File#S:21=2

 

[ceilingwalker]

Could it also be the inputs? That seems to be the only change the processor makes is to the input image table, when I connect and disconnect the field wiring.

 

[Ron Beaufort]

I've been traveling for the Thanksgiving holiday - and have had very little time to work on your questions ... give me a call and I'll try to help you out by phone ... this is way too much to type ...

 

[dash]

Digging up an old thread, but I am very interested in what the problem may have been. I have a similar issue (other than nothing has been reconfigured). This has occurred twice in the past 6 months with different analog input modules (both are 1746-NI8).

The customer was wanting to get back to running so I had him switch the key to program and then back to run and the problem cleared. Both of these modules are in an expansion rack (slots 10 and 11). It kind of makes me wonder if we have an issue with the rack.

Thanks for any insight.

Darren

 

[Adam303]

@dash see if this helps

 

[Adam303]

@ceiligwalker
What Ron said

just guessing - maybe the new configuration you tried didn't match the actual hardware setup - and the module caused a fault as a result ... you might also trying to just "enable" one of RTD channels at a time to possibly tell which channel was causing the error ...

 

[dash]

@Adam303 Thanks, had not seen that tech note. Will get maintenance to check this weekend when down.