Error MSg Slc 500

Hi i am having this reoccurring error on a SLC 500 Allen Bradley plc.
Rack Data Detected, check slot 17 and sometimes 19

what could be the cause and solution.
Any help would be appreciated.

please define your processor, rack(s), and physical i/o.

i cannot answer without more details.

regards,
james

SLC-500 controllers require all of their I/O modules to be securely seated and functional before they will run their user program.

If you have a damaged or defective module, the controller will fault and will try to indicate which slot number the defective module is in.

The controller cannot always determine the correct slot, unfortunately. And sometimes the problem is with the field wiring, rather than a damaged module.

The most common field wiring problem is large inductive loads (solenoids, motor starters) on relay outputs without surge suppressors. Very noisy analog input modules also can cause this type of fault.

Here is the backup of the above file it has no remote I/O and is all hardwired to PLC via junction boxes.

Thanks for the replies.

I also have a Allen bradley flex 1794-IRT8 connected remotely to a AB 1756 CNB/B and Logix 5555 processor, the data that comes from this card is being displayed on an ifix scada. The problem is the values coming from this card freez up. then we change the card it diplays the real values but after some time it will freeze up again.

Could this be a card or back rack or ethernet comms problem but on the remote io its only this card with a problem.

sharmn1 said:

I also have a Allen bradley flex 1794-IRT8 connected remotely to a AB 1756 CNB/B and Logix 5555 processor, the data that comes from this card is being displayed on an ifix scada. The problem is the values coming from this card freez up. then we change the card it diplays the real values but after some time it will freeze up again.

Could this be a card or back rack or ethernet comms problem but on the remote io its only this card with a problem.

Click to expand...

If by freeze up, make sure that it is not RSLinx that is freezing up first (perhaps some test logic with a timer so you can see how long the PLC sees unchanged data)...then

I would first suspect ethernet. Media first. I have seen this problem too, it was a smashed and wet ethernet cable that would cause critically placed photocell digital inputs to be "off" by up to 2 seconds from reality, but never fault. I never got around to adding my own fault detection for the apparent retries that were going on.

As for the SLC, I agree with what Eddie said. Reseat all the cards. Carefully inspect the chassis connector cable, make sure it is away from high voltages and sources of electrical noise. I once had a really flaky analog card which, in any rack I tried, would cause the slot to its left to fault, but only after it had run for about an hour or longer. In slot 1 it would give the 'slot fault, unable to id which one...' error, in other slots it would "blame its little brother", led me in circles finding it the first time on the roof in the blinding sun in an HVAC panel.

Thanks for the help will have a look at all these variables and start a process of elemination.

The IRT8 card freezes its dat indefinetly till the card has to be replaced. Even a reboot of the panel does not help.The only thing is this is the 5th card in a rack of 7, the 6th one also experienced this problem, which leads me to beleive coulf the back base have a fault causing the data on the bus to fail.

The maachine is running prduction and is in a high carbon dust area which could cause some shorting out.

With Flex I/O, it is definitely a common thing to have bent or loose connections at the base to base connectors. Oh, man I have lost a few hours hunting for one that either broke off or pushed in and would only take out half of a 1794-OB16 two slots away once the machine was warm and vibrating just right...

Definitely look at and very carefully reseat those bases if you keep having the same faults. This is assuming that those cards are not permanently damaged, in which case I would look at was is hardwired to them.

We used a lot of Flex I/O in areas with some carbon dust and they were okay, a few failures, in the tire industry, many times we had to specify conformal coatings I think mainly due to other chemicals like sulphur in the dust that would grow into semiconductors on silver connections, even refrigeration soldering. The Flex I/O once solidly mounted is pretty solid though, we did not have to use special modules, just had to be careful at commissioning, use good well anchored din rail and end barriers to keep them snug and solid.

Thanks i will just need to be handed the machine in the mean time going to test the cards that have been removed to confirm if working.

sharmn1 said:

Thanks i will just need to be handed the machine in the mean time going to test the cards that have been removed to confirm if working.

Click to expand...

Get your flashlight charged and your magnifying glass ready and look at those little gold pins, if any are missing bent or pushed in, odd things may happen, and just the act of reseating all of the bases and putting the cards all back in can often make a ghost problem like this go away for good, or until the next disturbance to the physical connections spawns a new one!