multiple modbus session

[kalpak]

I need to connect slaves with RS232 port to PC, so each slave will have one PC serial port connected to it. And the protocol is modbus. Will Labview/ OPC support more that one serial port on the PC with modbus protocol?

[unclebump]

Yes. There is a modbus library for 7.1 and it was downgraded to 7.0. You can write the communication code inside labview to talk with the devices. Or you can use an opc server and let that program take care of all the communication stuff. Then you use the labview DSC module to access the slave data. I use kepware as my opc server. I haven't upgraded to 8.0 so there could be some new methods in that version.

[kalpak]

Thanks, downloaded it and tried to use it, but not successful. I am using the Labview 7.1, will it work? Or does it need 7.0?

[unclebump]

Yes, the library will work in 7.1 format. I had someone save it back to 7.0 format. Here is an example for a modbus serial query.