Java PLC communication over USB-to-RS232

I am trying to communicate with Omron PLC CP1E-N40DR-A over USB-to-RS232 cable, using a Java program. Following is my basic code—



This code produces no effect on the DM area. In this code I am trying write “0070” at location “0620”. The connector and its driver are alright because CX-Programmer is working fine using the same cable.

Any pointers for this would certainly help me.

Thanks

Not knowing about that particular PLC, suggest going online with it if possible while testing your program. See if you can pick up any error messages on the fly.

Have a look at this (VB, not Java) tutorial on Omron Hostlink:

http://accautomation.ca/how-to-implement-the-omron-plc-host-link-protocol/

Everything looks correct to me. Are you sure about the 7-data/2-stop/even parity framing ?

Are you looking for a reply from the PLC, or just looking to see if the data values change, using a different port ?

Ken Roach said:

Have a look at this (VB, not Java) tutorial on Omron Hostlink:

http://accautomation.ca/how-to-implement-the-omron-plc-host-link-protocol/

Everything looks correct to me. Are you sure about the 7-data/2-stop/even parity framing ?

Are you looking for a reply from the PLC, or just looking to see if the data values change, using a different port ?

Click to expand...

I have taken help from the above link only and translated it into Java. I have translated it to Python. It is working fine there. The Java program isn't working. I am using purejavacomm library for serial communication.

I want to write/read DM area of the PLC.

Regards

http://www.drdobbs.com/jvm/java-communications-without-jni/240164940

http://www.sparetimelabs.com/purejavacomm/purejavacomm.php

Here are a couple of threads showing the use of purejavacomm.

Does your current program cause the transmission lights on the PLC to flash. If not check the FLOWCONTROL_XONXOFF.

Hope this helps you out.
Regards,

jangid said:

I have taken help from the above link only and translated it into Java. I have translated it to Python. It is working fine there. The Java program isn't working. I am using purejavacomm library for serial communication.

I want to write/read DM area of the PLC.

Regards

Click to expand...

Sounds like an issue with that Java lib then as opposed to a PLC comm issue. Surprised Java doesn't have built-in serial capabilities and needs a 3rd party lib.