USB to Serial problem (A&B 1200)

I've been monitoring this forum for a while, but now have run into a problem that someone surely has seen before. I have quite a bit of experience with AutomationDirect, Omron and Idec and A&B PLCs. A couple of years ago I had to translate a program from AD to Omron and then to A&B. Needless to say, the last translation was the toughest to do.

I managed most of it and then the project was taken over by an experienced PC programmer when I went on our annual trip to Florida for three months. Now he is unavailable and I now have a new laptop which does not have a serial connector for the A&B cable. The USB to serial connector is listed as Comm 5 in hardware properties, but I can't get the computer to talk to the A&B 1200 PLC.

I've gone through the help files, have the Lynx software and other software installed, but can't seem to make any progress.

The machine is used to put hooks or hangers on plant pots. Doesn't sound like much of a deal, but a typical greenhouse might have to do 6 million of these pots in a short growing season. That is a job that people should not be doing. It is a painful operation that is much better done by machine.

Thanks for any information.

MicroLogix 1200 controllers can be set up for several different communications protocols, including DF1 and DH-485.

If yours is set up for DH485, and you previously used the "1747-PIC/AIC+" driver in RSLinx, then you can't use this PC's standard USB/RS232 converter and will need a 1747-UIC from Allen-Bradley. As you said, this has been discussed on this Forum at length.

If the controller was set up for DF-1 protocol (default out of the box, also the default when you press the "Default Communications" button on the controller) then you should be able to use your USB/RS232 converter with the good old DF1 driver in RSLinx.

Many USB/RS232 converters do not support the rapid changes in framing settings necessary to use the "Autoconfig" button in the RSLinx DF1 driver. Try setting the driver up for 19200 baud, no handshaking, Device Type = SLC/MicroLogix and error checking = CRC.

Thanks, Ken for the useful reply. The reason I needed to use the new computer is that the keyboard on my older laptop was going bad. Nice to have keys like "E" "G" "I" and others didn't work anymore. Then I had the brilliant (if obvious) idea of using an external keyboard. That works just fine.

So, as long as I can use the older laptop, the defined problem has gone away for now. I will probably still have to address it in the future, but the present crisis is over.

Thanks.

Earle Rich
Mont Vernon, NH

I would also like to mention that some devices do not like it when the comm port is anything other than 1-4. You can go into control panel and change it to one of the lower ones.

Bob

Try a different USB->Serial convertor. The first one I used set my Coms to ridiculous numbers that I couldn't change. I got a new convertor that allows me to chose to COM port. Works great!