Uploading from a Micrologix 1500

I was asked to troubleshoot a system being controlled by a Micrologix 1500. I assemed that I could walk up to it and upload the program into RSLogix 500. RSLinx was not seeing the PLC on node 1 - the laptop is on node 0. Am I missing something here? I know my setup works because I just did a startup yesterday with the same PLC model. I've never had a problem but I've always written the program and downloaded it. Do I need to create a program before I can upload one?

What driver are you using in RSLinx. If DF1, have you tried autoconfigue?
If that does not work the PLC port may be configured for DH485. If so you will have to use the PIC/AIC driver in RSLinx. You will need a real serial port for this driver. The ML1500 has a button on it, under the cover labled comm. If you push this button in for a couple of seconds it will return the PLC port to its default configurtion ( DF1 )

It maybe the port(s) on the ML1500 have been set to DH485 and you're using a DF1 driver in Linx (or vice versa).

You should be able to upload without performing anything else first (but obviously you will need a copy of the offline file to give you the necessary addresses and symbol descriptions)

Hope this helps......

Thanks guys - I'll try the comms reset. Shoulda thought of it because it's an hours drive away.