S7 200 communication problem

Hi all,
I`m having problems communicating with an S7 200 Siemens plc.
I`m using a siemens PG programmer and RS232/ppi cable. All Dip switches seem correct, i`m scanning with all baud speeds selected and i'm on the correct com port. My programmer is seeing the plc, but it is classified as "unknown" and I cannot access its program or download to it.
Does anybody know what the "unknown" label indicates?
Thanks.

Unknown, means it can see a device but doesn't know what it is.

A few things to try:

Do you have another PLC or cable, try using those to narrow down the problem to possibly being a bad port or cable?

Unknown can pop up if the baud rate is wrong, I think I remember a check all baud rates box that you can check.

Try cycling power on the PLC.

Try putting the PLC into "Stop" mode instead of run. It is possible to configure the ports for a "Freeport" mode, that you wouldn't be able to communicate with in run mode.

I have another (brand new) rs232/ppi unit which gives me the same result. I also took the programmer to another machine with an S7 200 in it and it flagged that plc up as unknown too..this is very strange as i was communicating with this device 2 weeks ago with the same set up. I have the 'all baud rates' box ticked too. Tried with the plc in 'stop' with no success. If i try to communicate with an omron plc, with its respective omron lead, it connects first time, so I know my port is correct too. Thanks for your reply Joltron.

its been a while since i used a S200 but this sounds like a cable problem, i know you tried a brand new lead, but i think if you go to comm devices installed ( like ppi cable, cards etc) and remove the ppi cable, then install new device for the new cable and try that, sorry i can't remember the exact path to do it but i definitely had that problem when trying to use a brand new cable

What kind of PLC are You using and what version of software ? Maybe updating Microwin will help ?

adfox said:

Maybe updating Microwin will help ?

Click to expand...

Yes if you have a older version of MicroWin and a newer CPU then this is one reason