Allen Bradley 1407CGCM showed up (CGCM fault) on HMI 1

[newelecteng]

Hi all

We are using Allen Bradley 1407CGCM for generators turbines . Before week ago an alarm showed up in HMI screen (CGCM1 fault). We try to reset but it does not cleared (still active). We got the same alarm before one month but it go when we reset. This alarm showed even though the unit was off.

thanks in advance

 

[Drivesrock]

Hello newelecteng.

Did you get anywhere with this? These AB CGCMs require connecting to with the Rockwell Studio 5000 S/W. Maybe that way you can find out what the fault alarm is?

Let us know how you got on.

 

[newelecteng]

Drivesrock

Actually this AB 1407-CGCM connected to Rockwell RSLogix5K. I trace every fault bit in PLC software but I couldn't find any fault. the fault came form CGCM FLT relay but in PLC all FLTrelay output is OK. So, it maybe internal hardware issue.

 

[catserveng]

Have you checked the CGCM Fault Relay Tab in the module properties report? It is described in Chapter 4 (near or at the end) dealing with Configuration.

Compare the boxes in the Fault Relay Tab to the output table, make sure they match.

Check the output of the Fault Relay, is it still active (pulled the Batt-) when power is removed from the CGCM?

What is the fault relay output wired to? If none of the faults programmed into the Fault Relay Tab are active then either the CGCM processor has failed, or the open collector output has been exposed to high voltage or too much current draw (limit is 500mA).

You do have a copy of the manual, right?

MikeL.

 

[newelecteng]

catserveng thanks for your feedback

Have you checked the CGCM Fault Relay Tab in the module properties report? It is described in Chapter 4 (near or at the end) dealing with Configuration.

i checked the fault relay configuration tap in CGCM module throw RSlogix5k there is just tow function that are activated (PT sensing loos and Over_excitation)
I uncheck these two function then apply and send the change to CGCM but FLTrelay still active.
I trace faults bits in CGCM scheduled read table but I couldn't find any single bit that active

Compare the boxes in the Fault Relay Tab to the output table, make sure they match.

do you mean the output table is CGCM scheduled read table in Rslogix5k If yes there is no fault bits that active is CGCM scheduled read table.

What is the fault relay output wired to? If none of the faults programmed into the Fault Relay Tab are active then either the CGCM processor has failed, or the open collector output has been exposed to high voltage or too much current draw (limit is 500mA).

The FLTRelay is wired to another external relay that do tow thing (1)Trip Gen. CB and (2) activate input module channel to Rslogix5k to generate (CGCM1 fault).
When I check the status of CGCM in module ifo. tab in RSlogix5k (there is no Major faults or Minor faults). and communication is fine for both control_net channels.
I also upgrade the frimarew from 4.6 to 4.8 but the alarm still active

Check the output of the Fault Relay, is it still active (pulled the Batt-) when power is removed from the CGCM?

I dont know what you mean but pulled the Batt-. when i switch the power off there is 2.3Mohm between FLtrealy and Batt-

 

[catserveng]

A diagram of the fault relay from the manual is attached, the open collector common is internally tied to BATT- in the CGCM. With the CGCM powered down, see if you have 24VDC between the Fault Relay output and 24+, if you have power the collector has failed (shorted), if you don't then power up the CGCM and repeat the check, if you now have 24VDC then the CGCM is calling for the fault relay to close, if no active faults are present then there is likely a problem with the CGCM.

One thing to note, over the years I have done troubleshooting on a fair number of these with multiple problems, although I am by no means a CGCM "expert". Most times I find an issue in the programming. If it worked before and no programming or wiring changes have been made, then the likely problem is the CGCM itself.

Overall it has been a pretty reliable product in my experience, but over the years I have had to replace a couple that just didn't work right and no apparent cause.

Hope that helps, MikeL.

 

[newelecteng]

the open collector common is internally tied to BATT- in the CGCM. With the CGCM powered down, see if you have 24VDC between the Fault Relay output and 24+, if you have power the collector has failed (shorted)

yup sir there 24VDC With the CGCM powered down. I wonder if it possible to open CGCM and try to rectify it from inside.

 

[catserveng]

No, the collector is a board level device, if it's shorted it somehow got fried. I guess you could try but the CGCM is a pretty complex device usually controlling expensive turbine and sometimes RICE based generator systems. Is that something you want to take a risk on?

There are a couple of options,

I think Rockwell may still have rebuilt CGCM's available, but the ControlNet version is getting much harder to come by, not sure which version you have.

Radwell sometimes has new, surplus or used tested modules available and do offer repair service,

https://www.radwell.com/en-US/Buy/A...-WycqvjvnbswY0_CmiaVn8MWuvED8vyRoCEm0QAvD_BwE

Not sure where in the world you are but a non-USA source for repair and possible refurbished replacement is the Unis Group in the UK, my previous experience with them have been positive,

https://www.unisgroup.co.uk/products/1407-cgcm/

Before you replace the failed CGCM make sure you fully investigate the fault relay output circuit, it is rare in my experience to have either collector (Fault or Redundancy relay) fail shorted without some kind of problem in the circuit. Things like directly connected to a large frame trip relay, not using a suppression device across the output load or a wiring fault have been contributors to a failed output collector in my experience, other users or forum members may additional or different opinions on that.

MikeL

 

[newelecteng]

thanks MikeL your feedback was very valuable.