ControlLogix and flash card corruption

[andrewf]

Hi guys, I have a problem with a particular customers site, they have various 1756 L61 series A and B processors. They have a occasional problem (about once a month) where if you attempt to go online with a processor via Ethernet the processor will stop and fault,If they power cycle the processor will be healthy and run normally until you go online again. if they then try to attempt to go online via the serial port on the processor then it will fault also. The only way to fix the problem is to remove the compact flash card and format it, as it appears it is corrupted. Once that is done then there are no problems going online.These processors have no batteries and so on power up they are loading from the compact flash. I cannot find any pattern to this occurring and it will happen on various processors. I have logged a ticket with Rockwell support some time ago but they have so far not been able to offer any solutions or suggestions. I happened to be talking to a fellow engineer who asked me about the same issue without me bringing it up as it has happened to him a few times recently. So has anybody else experienced this problem?

 

[OkiePC]

EDIT: So you can't get online to check the CPU utilization...can you monitor its web page? Going online could push the CPU utilization over a fault threshhold.

And, Install batteries.

Try a New CF Card, p[-rhaps.

Check the code for logic that might cause the fault intentionally?

That is a strange one, so I am at a loss for other possible causes. If the EDIT above turns out to be the issue then something needs adjustment in the task scheduling...

I did have a Controllogix PLC programemd by others, that would sh*t its brains out randomly but rarely. Installing the A/B brand CF card as a backup to the batteries, has solved that problem for almost two years now IIRC.

 

[andrewf]

EDIT: So you can't get online to check the CPU utilization...can you monitor its web page? Going online could push the CPU utilization over a fault threshhold.

And, Install batteries.

Try a New CF Card, p[-rhaps.

Check the code for logic that might cause the fault intentionally?

That is a strange one, so I am at a loss for other possible causes. If the EDIT above turns out to be the issue then something needs adjustment in the task scheduling...

I did have a Controllogix PLC programemd by others, that would sh*t its brains out randomly but rarely. Installing the A/B brand CF card as a backup to the batteries, has solved that problem for almost two years now IIRC.

Thanks for the response.

No can't get online via Ethernet, Serial or web interface. But we have measured CPU utilisation when it is working OK and it was only a couple of percent from memory.
They are using AB CF flash cards and each time it happens they are replacing with new ones.
They have about 12 processors and it has occurred on about 6 of them so far with only 1 repeat of a processor.
They Cannot use a battery for environmental reasons

Also Rockwell have checked serial numbers on processor/Enbt cards to make sure they have no issues.

It is a very strange problem.

 

[OkiePC]

Thanks for the response.

No can't get online via Ethernet, Serial or web interface. But we have measured CPU utilisation when it is working OK and it was only a couple of percent from memory.
They are using AB CF flash cards and each time it happens they are replacing with new ones.
They have about 12 processors and it has occurred on about 6 of them so far with only 1 repeat of a processor.
They Cannot use a battery for environmental reasons

Also Rockwell have checked serial numbers on processor/Enbt cards to make sure they have no issues.

It is a very strange problem.

What? No batteries by rule for what reason? Jeesh...
New memory card every time?
Is there a significant problem with electrical noise in and around this system?


I would think that in a critical application that a UPS would be used in place of batteries. I have never heard of a restriction against PLC backup batteries...whose rule is this?