Omega CN616A Temperature Controller

[John92124]

I am looking for information on how to communicate with an Omega CN616A Temperature controller over MODBUS / RTU using LabVIEW.  I have down loaded the Modbus Master, Plasmionique package.  I have a USB to  RS232 cable (COM 4).  Omega provides an application that communicates with the CN616A device, and I am able to use this.  I have tried different configurations in LabVIEW but I'm not able to read any data.

Note.  The earlier CN616 module was able to use a serial port, but the CN616A is only ModBus.

MB_Master - User Guide.pdf

[Rolf Kalbermatter]

On 1/15/2022 at 11:47 PM, John92124 said:

I am looking for information on how to communicate with an Omega CN616A Temperature controller over MODBUS / RTU using LabVIEW.  I have down loaded the Modbus Master, Plasmionique package.  I have a USB to  RS232 cable (COM 4).  Omega provides an application that communicates with the CN616A device, and I am able to use this.  I have tried different configurations in LabVIEW but I'm not able to read any data.

Note.  The earlier CN616 module was able to use a serial port, but the CN616A is only ModBus.

MB_Master - User Guide.pdf 1.08 MB · 1 download

What have you tried so far? It should not be a big problem to use this with any of the Modbus libraries out there. I usually use the NI Modbus library but I think the Plasmionique library should work too. You need to make sure to use the correct Modbus Unit ID, which Omega calls Modbus Address (Function 34) in its menu structure on the display.

They need to match if you want to read any value (Read Holding Register). For writes you also can use a Unit ID of 0 which will address any connected Omega Unit but it will not return any indication if the write was successful. The default address if the Omega Units should be 1 when delivered.

Then you need to figure out what register address to read and/or write. The according addresses are documented in chapter 19 of this manual.

 

Edited January 18, 2022 by Rolf Kalbermatter