I HAVE A MICROLOGIX 1000 AND I HAVE A BAD CONFIGURATION FOR THE COMM PORT AND IS IMPOSSIBLE TO COMMINUCATE. IT IS POSSIBLE TO RESET THE MICROLOGIX (FACTORY SETING) ?

As far as I know of, if the hardware is in working order you should be able to talk to it. There is no ASCII mode on a micro 1000, nor can you turn the port "off" like on the SLCs. It is always up and running, in system mode, using DF1 or DH485.

Are you sure your computer and cable are up to snuff? (i.e. will it communicate with another uL1000?) Tried doing an auto-config in RSLinx? Tried every possible baud rate and node number for 485?

I guess after all that I didn't even bother to answer your question :)

AFAIK, There is no way to "default" a micrologix like you can with a SLC. The user program is stored in Flash memory. there is no battery. I'm sure A-B has tools to communicate directly with the hardware (JTAG boundary scan?) but the rest of us have nothing but a serial port to work with.

Assuming you've been using a serial port to try and talk to it with DF1 and have no success I suspect the port is configured for DH485. In this case, the only way I've been able to get around this is to use a UIC (USB to DH485 converter) and manually configure the port baud rate in RXLinx until the connection is successfull.