micrologix 1400 loosing program

Join Date
May 2006
Location
huddersfield
Posts
67
Hi has anyone had any problems with a Allen Bradley Micrologix 1400 loosing its program.I have one on site that has completely wiped its program twice now, and it looks like i may have another one on a different site that has done the same.????
 
I had this problem twice when they first came out. When something was connected to the Ethernet port, and power was removed, the processor would fault and lose the program. I had to flash to a newer revision to fix the issue. It worked on one of them, but not the second. AB gave me an RMA on it, even though the warranty was up on it. I haven't had any issues since.

It may not be the same issue, but may be something to look into. How old is it? What is the firmware version?
 
Not sure on the firmware version but it was bought and fitted in December 2011 so i would imagine its the newer firmware.It has got a hmi connected via ethernet so im wondering if this is the problem.
 
Make sure that you have it grounded as instructed to do so in the installation instructions. Failing to do so can result in loss of program for no apparent reason!! <--Voice of experience! :ROFLMAO:
 
grounding

Grounding has been mentioned to me before about this problem.We have the plc mounted on rail which is riveted to a metal backplate using metal rivets.The terminals are also on a riveted rail to the same backplate and the earth terminals are screwed to this rail.I would expect this to be fine with regards the grounding, it also says that as long as the plate is grounded then you dont have to take a extra ground cable to the tab on the plc in the manual.Maybe its better to this also??
 
Make sure you have surge protection on all inductive loads. ( solenoids, motor starters)

See pdf
 
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At some point i almost understand that grounding is the usual answer from AB for any unaswered question...Is it ?
Yes Grounds need to be good but i doesn't understand how it could erase an eeprom memory, a memory card or a flash memory....
Surge protection is probably more important to my point of view to limit high voltage.
For filtering reasons, i like to use a 24vdc plc powered by a good protected powersupply instead of a 120vac comming from the utility power that include all the garbage availaible....But it cost a little more and some aren't availaible.

I also get an AB losing is program but an old SLC5/03 and it was during lightning storm...it does it 3 times and then i replaced the plc and installed surge protections and never heard back from it.
 
I also agree that i find it hard to believe that bad grounding will cause the plc to erase the program.When you say you fitted surge protection was this on the input supply to the plc as well as ouputs to inductive loads??
 
yes both a 120vac surge surpressor on the power input side (Maybe 220 for you) along with a line filter just in case and all basically all our panels are designed with surge arrestor on everything inductive from small interface relay, to contactors for ac load.
For DC load just a reverse diode is fine
Usually surge arrestor and diodes are availaible as an accessori plug-in module for relay and contactors from most of the good brand out there.
 
surge protection

I appreciate what you are saying about the surge protection,just find it strange how i probably use 30-40 of these plc,s a year for the past 5 years with no surge protection and its only 1 maybe 2 that i have experianced the problem of it erasing its program??
 
Check your field wiring for shorts.

I installed 4 Micrologix 1000's a few years back and they would regularly drop their programs. The trigger was traced down to shorts in the field wired 24VDC inputs. Because the I/O shared the same power source as the processor, it would pull down the supply voltage low enough to fault the processor. Rockwells answer was to upgrade to new processors with higher than a revision E, (We had Rev C). We did nothing other than swap the units and they never lost the program again.
 
I appreciate what you are saying about the surge protection,just find it strange how i probably use 30-40 of these plc,s a year for the past 5 years with no surge protection and its only 1 maybe 2 that i have experianced the problem of it erasing its program??

yeah but if the 35 others were running on clean utility line vs the other 2 wasn'T, you get it!

Like insurrance is useless until you got a problem...
 
It's probably not the noise/surges/etc. physically wiping the program but the PLC itself. We had similar symptoms from a 5/03 traced to the rack power supply. When a particular voltage would drop, the PLC would decide that it couldn't reliably control its outputs and would wipe itself as a safety measure. It would be nice if it set a flag or turned on a light, though, letting us know what happened.
 
It's probably not the noise/surges/etc. physically wiping the program but the PLC itself. We had similar symptoms from a 5/03 traced to the rack power supply. When a particular voltage would drop, the PLC would decide that it couldn't reliably control its outputs and would wipe itself as a safety measure. It would be nice if it set a flag or turned on a light, though, letting us know what happened.

you could use a live beat normally open contact that would close with a healty program and when this output open, you will know something is going wrong...
 

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