Instrument Control (GPIB, Serial, VISA, IVI)

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Modbus Time reads into register fine but the output of the PLC to my indicator time is a different reading.

My problem; I am shifting into a register a time in seconds I16 / decimal and reading an indicator modbus output of a PLC, using DSC software control. 

 

The time gets shifted into the register correctly but when I try and read it out of the PLC to an indicator it is not the same number.  I can read the correct time out of the PLC using it's software so, I know the register is getting the right number but LabVIEW is not reading the data correctly coming out of the Modbus PLC.   

 

It seems to me that on of the LabVIEW classes coverd this but I do not remember what the fix was.  I think it was in the DAQ Instrumentation class. 

 

Has anyone seen this and know of a fix?  I am using a representation (I16) and display format (decimal).

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I think we will need to see your code. Modbus data is transmitted as bytes. It is up to the labview program to convert the bytes into the correct data format. I16,U16,U32,DBL,... Usually this involves using a typecast function. Show us your code and the data values.

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