I have been using GModbus over serial for a decade now without issue but I have run into licensing issues since Saphire is no longer part of the NI team. I am now trying to use the NI Modbus tool but I am getting bad data back from my instrument which is a Watlow temperature controller. I chose to use similar programming as I did with GModbus and have tried various methods but I still get bad data from the instrument. I am thinking that I may not be converting it properly or not applying the tool correctly and it would be great if I had a second pair of eyes to look at it and see what I am doing wrong. Any help would be appreciated.

Hi teslac, @teslac wrote: I am getting bad numbers back from the Watlow which is reading room temperature (2.66E-314). Are you sure you want to read DBL values? Modbus devices typically handle floats as SGL - and your 2.66E-314 is a clear DBL value… See these conversions: The upper conversion uses a DBL value, the lower a SGL value! (All strings in hex display mode.) Which "raw" data do you receive? Can you show the received string/byte array?