How can I communicate the instrumnet in labview using RS485 interface?

[serf408]

I am using NI USB RS485 to connect the instrument, but I donot have instrument driver,I have to use VISA write and read data. the connection and serial setting are correct, I used a software ModScan32 from win-tech, the communication works well. I want to use the labview as my platform, How can I use VISA? please give me any clue or sample code. the instrument has a Modbus commmunication protocol.ThankS!

[DiegoF]

Hi,

VISA allows you to send/receive string data to/from the instrument. Serial communication with RS-485 is just like RS-232, so any of the labVIEW examples on serial will work. For serial you basically need to use VISA Read and write, that's it.

If you need information on what to send, you can check out the modbus website (www.modbus.org) and the documentation for the device.

Hope this helps.

DiegoF
National Instruments.