Can't Map Serial Port to Create a Modbus IO Server for a cRIO in LabVIEW

Updated Aug 10, 2020

Issue Details

When creating a Modbus IO server, the options shown for serial port are COM1-COM32


But on NI MAX, the onboard serial port I'm using is named as ASRL1::INSTR and I have no way of changing it to a COMx port



How can I create an Modbus IO server on my cRIO? 

Solution

The Modbus Serial IO servers are based on OPC DA, which uses Windows COM technology that does not have compatibility with Linux.

To create an OPC server on the cRIO, you'll net to use the Modbus APIs that will work and map the serial ports correctly. Reference the Modbus Library example on NI example finder for a good way to get started.