90-30 "Service Request Busy" error-S95

One of our 90-30 364CPUs was locked up with Service Request busy on our last maintenance day. I had an opportunity to try some things, none of which worked. First I removed the Ethernet cable from the 10 Base T Port, waited 4 minutes, plugged it back in and pushed the Ethernet restart button. (4 minutes being the longest time we could go with out communications. Tried the same thing again, but waited ½ an hour. Also unplugged the serial cable, it was hooked up to a computer, but Logicmaster was not running on it. Tried again for another ½ hour at the end of which I left the Ethernet unplugged and tried to make the change with the serial cable. Service request was still busy. In the end I had to cycle power to the PLC to clear it.

I would like another option to clear this problem. It only happens once in a blue moon, but still, I would like to be able access the plc without having to shut it down.

Any suggestions would be appreciated.

One other note...we are running LM90 ver 9.02

I am not positive but I think the error you have given is a communication error for LM90...ie the software cant communicate with processor. I dont think that is the real problem, I think the processor is locking up causing the inability to communicate with LM90.

Once running again you may want to check the CPU fault tables etc to see if you can determine why it locked up. You may want to check file size to determine if there may be memory issues that could cause problems. The manual for Enet communications may offer ideas on troubleshooting the Enet setup etc, EGD may need to be fine tuned.

Maybe Steve will come along and can give more in depth help.