Micrologix 1000 Fault Problem

[themullet 0]

Hi Guys & Gals, I was wondering if somebody might be able to help. I am having a strange problem with a Micrologix 1000. This morning one of the machine operators turned off the power to the control panel, hence shutting down the plc. On power up the plc failed to go back into run mode. Anyway I went online with the PLC and saw that there was a Fault. I cleared the fault successfully or so it seemed, but when I put the PLC back into Run Mode, it faulted again. The only way I seem to be able to get around this, is to do a full re-download of the program. I have attached a screenshot of the error: Major Error S:6 = 2h. I have had a look in the manuals to see what the problem might be, but I haven't really been able to find out that much. This is about the third or fourth time that this has occured, in the exact same circumstances. I am kinda thinking that the PLC doesn't like the power-up, perhaps an irregular voltage or something????? Maybe I need a new PLC?????? I would be very grateful if somebody would be able to give me any help at all. Thanks in advance, Rob

[Mike Dyble 0]

According to my manual this fault can be caused by electrical noise. Is the power switching on cleanly? Can you isolate the PLC separately from the rest of the machine, if so after you power down isolate the CPU and only re-energise after you have put the main power switch back on, and see if this makes any difference.

[Mickey 71]

Surge protection for incoming power will help. UPS for your processors power will help. Check your grounding then check it again then check it again. Surge protection on all outputs will also help.

[splicer480 0]

I've got about 60 PLC's in the plant. Around 30 of them are the micrologix 1000's. All the machines are stand alone units (no networking at all) The operators move the machines all around the plant floor and plug them in and go. I've only had (1) Micrologix 1000 ever fault on me on its own. It would get a major fault and lose all retentive data. Some days it would happen 2 or 3 times, sometimes it would run for 2 or 3 days no problem. We ended up replacing the 1000 with a new one and have not had a problem since. (about a year now) It was a real pain dragging the laptop down to reset the fault whenever it happened.

[TEJ 0]

Dear ROB, Your problem seems like a manufacturing defect. I had a similar kind of experience and i came to understand that there is SRAM which is a cause for this. Please read the attached document which will give a clear idea about it. Further clarification, let me know. TEJ ML_ROCKWELL_FAULT.doc

[swimmy67 9]

It has been my experience with the ML1000 when clearing the fault you have to write a "0" to S:5/8 Retentive Data, in order for the fault to be cleared successfully. Using the attached picture as a guide, highlight the "1" in S:5/8 and type in a "0" and press enter. Press the "Clear Fault" button. Try putting it back into run mode.

[mbeecher 0]

I had the same issue with a ML1000 solid red fault light. Everytime I cleared the fault, try to put it back in run mode, it would fault out again.. I read and did what Swimmy67 said to do. It worked I was able to put it back into run mode..Only problem is that the sensor that caused the fault is still not working, I've replaced with a new one an still not working. So, I went ahead an put the input on another input bit. nothing...the program will not read the input at all. So, then I replaced the PLC and downloaded the program over into it. Nothing, everything works except the sensor input NO signal to input,, I have 24v from plc to sensor. Need some help guys... I did look at the attached file that TEJ sent out looks like this ML1000 1761-L32BWA is on the list... need some help!!!!!!!!!!!! Edited 14 May 2015 by mbeecher

[AndrewG 13]

Has the sensor ever worked? Are you confident the sensor is wired correctly and there is nothing wrong with the wires (no frayed wires, shorts, etc)?