You're welcome.
Adding function codes will definitely dig down deeper into the code than I first thought. I recommend starting with the MB Master Query VI and looking down through all the VI's and subVI's to understand what each does. I think if you are careful, you could modify the code without actually breaking it too much. It looks like the key factor for the function codes is the Typedef control for MB Modbus Data Unit. (also possibly MB Modbus Command.) You could add the new function codes to that. If you rename them, you will have to relink the controls all throughout the MB code to the new name. If you just add new function codes to the typedef, you may not have to do as much relinking. The risk is that you could break too much, it may be a lot of work fixing everything. But you could always download the modbus library again.
With new function codes added to MB Modbus Data Unit, and always using the Use Modbus Data Unit when using the MB Master Query when you need to use those codes (because it gives direct raw access to each and every byte in the command), you'll be able to get this to work.
