ControlLogix 1757-SRM problem

Hi, we have a problem with a 1757-SRM module (ControlLogix System Redundancy module) used in one our projects. The OK LED on the SRM is solid red and the power up self test gets stuck on TH73. Has anyone come across anything like this. Could you advise what is the problem and its possible solution.

Appreciate your help.

anybody?

I haven't seen it. But I do have some questions and suggestions.

First, check Allen-Bradley's literature. There will be a page that explains what the LED signals mean. Sometimes this helps.

And here are some things we may need to know to help you:

1) Do you have the fiber cable on the SRM module connected to another SRM module?

2) What cards do you have in the PLC racks? Are they in the same slot in each?

3) Have you installed the same version of the firmware in each SRM module, processor, and i/o card?

4) What version of the firmware & software are you using?

AK

This tech note has to much info to re-capp so...

http://domino.automation.rockwell.c...7D95238346BA613885256AFB006E8EB3?OpenDocument

Hopefully this will help, I think your dealing with a firmware problem and as the technote highlights, the firmware in the SRM may not be the problem.

Bitmore

Thanks for the replies.

akreel,
Allen-Bradley's literature doesn't mention anything about the startup tests for the SRM module. There is no manual for the SRM module. Only installation instructions. The installation instructions booklet does give information about the error codes but nothing about the startup self test codes.

Regarding your questions,
1) The fiber cable is connected to the two SRM modules
2) The cards in the various slots are as follows:
Slot 1: 1756-CNBR Ver. 5.36
Slot 2: 1756-CNBR Ver. 5.36
Slot 3: 1756-L55M13 Ver. 11.6
Slot 4,5: Empty
Slot 6,7: 1757-SRM Ver. 3.25
3) I have installed the same version of firmware in each SRM, processor and CNBR
4) Software version 11.11

The system was working fine after commissioning. One fine day the maintenance guy calls up and tells me that the redundancy is not OK.
On first observation, the LED display on the SRM was blank and the OK LED was solid red.
So I cycled power to the secondary chassis. This is when the SRM module didn't go past startup self test TH73 and I also get the following message on the CNBRs:
ASSERT: wait4sbm.c line 0114

I had the same Problem with the SRM Module, I tried the below steps and found that the fault(TH73) was recovered.

1. Remove the SRM Module from the Chassis.
2. Unscrew the Module Cover and remove the PCB set.
3. Dismantle both the PCB's from each other.
4. Remove the dust particles from the PCB's using the Blower.
5. Keep the PCB's asside for around 10 Minutes.
6. ReConnect the PCB's and place it back inside the Slot Cover.
7. Install the SRM Module inside the Chasis and Switch it ON.
8. Hope it will work.

If not, repeat the above steps 2 to 3 times.

Thanks.
Salin Jayasankar

Salin75 said:

....If not, repeat the above steps 2 to 3 times.

Click to expand...

"Don't force it, get a bigger hammer"

Well I sure hope the OP got it fixed by now