MicroLogix 1000 1761-L20AWA-5A

[fosti 0]

I have a plc that was removed from a piece of equipment that was being scraped.I cannpt program this unit becaue it was password protected and was wondering if there was a way to get around it ,I don't really care about the program that is in it currently.I just want to be able to use it and if not I will have to toss it. I believe there must be a way to use some sort of factory reset (master password) in lieu of tossin it out. Thanks Fosti Edited 20 Nov 2005 by fosti

[Snerkel 0]

If you don't find any other answer what you can do (at least with the mains powered ones) is to short circuit the aux 24v DC output while the PLC is running, this generally instantly wipes the memory. Of course if you blow it up then I am not responsible. ps reason I know this is we had a machine that regularly had shorts on the PLC aux out when the operator kept cutting a sensor cable by mistake (until we redesigned it). Everytime this occured the program was erased.

[Ken Roach 194]

You can reset a password-protected MicroLogix with the reset code "65257636", as described in the Rockwell Automation knowledgebase document: A16851 - Clearing password protected Micrologix & SLC500 processors Shorting the 24VDC auxiliary supply does also clear the memory, but it's not really a recommended practice.