SLC 500 Fault

I was online with a 5/05 and a machine wasn't finishing its cycle. I saw that the reason it wasn't finishing was that a datacoupler had stopped communicating because the machine had timed out.

I attempted to do an online edit to branch around the XIC that was giving me trouble and I was immediately kicked offline. The PLC faulted and I wasn't able to go back online with it. It gave me an error message that said that I had to either Download or load from EEPROM.

So I have two questions:

1) What happened

2) Would loading from EEPROM have saved me from having to Download?

I have had similar problems a few years ago. When I attempted to modify a program online I was 'kicked" off-line and had to download program to SLC again. After some Investigation it wa sfound that my particular problem was a bug with that version of RSlogix500. If you tried to modify a branch part of a bigger multi-ple nested branch (in this case 7 nested branches) then the PLC would corrupt it's program. We had to connect locally and re-download the program. At that time Rockwell Supports answer was "don't attempt to modify a nested branch while on-line" Pretty sure that was a SLC503

I had same promblem.

1. get a copy of offline program.
2. under i/o configration- reselect the processor name again.
3. download the program to the Processor it should be ok

good luck

Same thing just happened to me. I was editing a rung with a nested branch - adding an XIC instruction. Had to download to get fault to clear. I have two other SLC 5/05 processors (same FRN) and have never had an issue.