AB Micrologix Fault Trapping

All,



My company manufacturers commercial food cooking equipment and I've incorporated PLC's (AB Micrologix 1000 & 1500) into our field test units (before a new product launch) to record the number of times a door opens/closes, contactor & relay operations, overall timer for power on and timers on major components.



We rarely, if ever, actually use the outputs. The data is used after a 6 month field trial to verify the location was a legitimate field test site, and then to determine the expected life span of the various internal devices (motors, pumps, valves, etc)



My problem is that these units occasionally fault and stop recording data. Since the outputs aren't used, the end user never knows the PLC is faulted/stopped.



The faults are mostly 0001H, and occasionally 0002H and 0009H, which I believe are power related. I did have a few faults where I exceeded the maximum numbers (32,000 and something on counters) but have corrected the logic for that.



Working with our local AB rep, we've added power filters, but this has not seemed to completely correct the problem.



As I'm not a controls engineer (electrical by education) I don't have the expertise that you folks have, and was wondering if I should have some standard rungs at the end of these kind of programs to detect and clear any faults in the "S" register?



My training on SLC 500 programming was back about 10 years ago, and I'm trying to schedule several of my employees to go to local AB training, but that may be months away yet depending on the budget etc.



Any help is deeply appreciated. Please let me know (either through post or email) if I need to supply more information.



Best Regards,



Roger

In the control properties you can set the units to ignor power up faults, and go into Run mode after power up. This should solve most of your problems.
If you want monitor the equipment durring a power outage, you could install a UPS to maintain the power.

Another way to narrow out your problem is to hook up an amp recorder. If you decide to hook up a UPS its best to use an inline ups rather than Line reactive

Those are pretty severe faults - in most cases, the program is getting wiped out and the default program is being loaded instead.

Have a look at the Fault Codes in Appendix D of the Instruction Set Reference (warning - this file is almost 9 MB). Your specific errors are on Acrobat pages 450-451. Based on their recommended actions, I would check grounding and power quality first . . .

Marc