Micrologix Problem

[Steve Sigma 0]

Can anybody help me with a problem i am encountering with a machine equiped with amicrologix 1000 plc. The processor occasioally indicates a fault (flashing red led) and all outputs are dissabled. When i connect the laptop and select 'goto error' from the status toolbar, a message reads 'Retentative data lost' and also flags a fault S:1/13 & S:5/8. If I reset these and put the processor back into run mode it works fine for about a day then the same fault appears. Does anypne know what may cause this. My plc knowledge is quite minimal so please don't be too technical. cheers

[mgvol 0]

MicroLogix are very sensitive to electrical noise/poor power quality. Ensure that the ML1000 is connected to a good solid ground via AWG14 ground wire. You might want to put a TVSS/Noise suppressor on the power feeding the ML1000 as well, unless you are sure you have good, stable power from something like a constant-voltage transformer. Also, if any of you outputs are controlling inductive loads (coils, solenoids, etc.), install surge suppressors across the outputs in accordance with the ML1000 user manual.

[TimWilborne 108]

Have a look at AB Knowledge Base tech note E19443 - MicroLogix 1000 faults with S:6 = 0005h, Retentive Data Has Been Lost If this is a 24 VDC powered unit I would look at the power supply first but it seem everything I can find points to noise. Edit - Mgvol beat me to it and did a much better job of explaining it but I'll leave this one. You may want to read the tech note too. Nice response time mgvol Edited 3 Feb 2006 by TWControls

[Steve Sigma 0]

Cheers guys, you both seem to have hit on the same cause. The unit is in a foundry environment and is subject to both inductive noise & metalic dust, so your diagnosis looks bang on, i'll get onto it as soon as possible. Thanks for your help

[TimWilborne 108]

Yea foundries are very CLEAN environments. You can duct tape the around the door seal of a panel so it won't open and still get that dust on everything inside.