Problem communication with Omron PLC CJ1M-CPU22

Dear Friends



I have two Omron PLCs CJ1M-CPU22 installed in two different units of machine. I use to go online with these PLCs through a cable CS1W-CN226. now I tried many time to go online with my PC but an error message generates “Failed to open communications with PLC. The device may be busy”

Please help what to do.

I see from some of your other posts that you are also using AB software. My first suggestion then is to check and make sure RSLinx is not running and using the computer's serial port.


If the RSLinx icon is visible in the system tray then right click on it and shut it down.



If RSLinx icon is not in the system tray then check and make sure that another application is not using the RS-232 port.

If you routinely access both PLCs then you may want to configure the RSlinx RS232 driver so that it starts manually or on demand instead of automatically.



I routinely use Omron and Modicon PLCs and occasionally GE but most of my ABs use E-net, so I configure my RSLinx serial driver to start manually. This requires that I remember to enter the driver configuration screen in RSlinx, select the RS232 driver in the list, and then click the START button to start the RS-232 driver. Since I mainly use e-net and seldom use AB RS232 its not a big deal. You will need to read the help file and determine which option works best for you.
1)Automatic and shut down RSlinx from the system tray
2)Reconfigure the driver for manual start/stop
3)Reconfigure the driver for on demand start - you manually still have to stop it.

Thank you Mr.Alaric.
Exactly the same problem as you mentioned. I shutdown the RS Linx and then connected with Omron PLC