AB MicroLogix 1000 CPU Fault

Hi
This is my first time posting but I have been reading the Q and A for a few years and find it very informative and interesting.
I have a problem as of late with a AB micrologix 1000 faulting with the following error "retentive data is lost" I am unable to clear this error by the normal way of going online and clearing major error.
The only way I can get the plc to work is to copy the lines of code from the original project file and create a new program and download it into the plc.
It has happened to me twice over the past few weeks. I am wondering if anybody came across it before.

Many Thanks

Aidan

We have started seeing this more often. the first one we replaced and that took care of it after that we have seen it about 6 times. Now we are considering the possibility of noise.

To clear it in the status file there is a bit for retentative dat loss not sure of the address but it it there. Go online and clear the fault then clear that bit then go to run.

Do you have any noise supression on the supply?

Drewcrew6

Thanks Drew

I have no noise suppression on the power supply but I have been having problems with the power supply been pulled down in the machine. That is probably the cause. Machine is been scrapped next year so I will keep resetting until then.

Thanks

Aidan

Retentitive Data Lost: its in the Status file S2, under errors tab S:5/13 at the bottom.

Short on time, but some info

I believe that there is a technote on this problem, as I think I have seen it twice in 2 separate locations. I think there was a batch of bad processors they made awhile back. I strongly suggest checking out the knowledgebase, as I am 95 percent sure you will find a technote for this very issue. I believe that this fault can be reset, but there's no telling when it will show the same symptoms. If I had the time, I'd find the technote for you, but I simply don't. Good luck.

Russ

http://rockwellautomation.custhelp.com/cgi-bin/rockwellautomation.cfg/php/enduser/std_adp.php?p_faqid=19267&p_created=977503802&p_sid=q8Ksy4oi&p_accessibility=0&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9ODIwJnBfcHJvZHM9MCZwX2NhdHM9MCZwX3B2PSZwX2N2PSZwX3NlYXJjaF90eXBlPWFuc3dlcnMuc2VhcmNoX2ZubCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PU1pY3JvbG9naXggMTAwMA**&p_li=&p_topview=1

Just in case the above link does not work see PDF

I had the same problem a few months ago. Rockwell replaced the PLC free of charge (there is a known problem with certain models).

I also had had no problem for months and the first time it happened was after a temperory power cut (probably caused by lightening somewhere), however it got worse rapidly eventually reaching the stage where I had to reset everytime the machine was powered up.

Until it is replaced as well as selecting clear major error you also have to reset the status bit (S5/13) before the PLC can be put into run. (Until I noticed that the status bit wasn't reseting by selecting clear major fault I also was downloading the whole program each time).