Converting Nominal Values to Temperature Values for the NI 9217 (FPGA Interface)

NI CompactRIO Device Drivers Help

Edition Date: December 2017

Part Number: 373197L-01

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Set the Calibration Mode to Calibrated in the C Series Module Properties dialog box for the NI 9217 if you want the FPGA I/O Node to return calibrated, fixed-point data for the module in units of ohms. If you set the Calibration Mode to Raw, the FPGA I/O Node returns uncalibrated, binary values for the module. After you convert these binary values to nominal values, you can convert the nominal resistance values into temperature values. You must convert these values in the host VI.

Using a VI to Convert Values

Refer to the RTD to Temp VI in the labview\examples\CompactRIO\Module Specific\NI 9217\NI 9217 Getting Started\NI 9217 Getting Started.lvproj for an example of converting nominal resistance values to temperature. You can use the RTD to Temp VI as a subVI in the host VI to convert nominal resistance values to temperature.

Using an Equation to Measure Temperature

You can use a linearization curve known as the Callendar-Van Dusen equation in the host VI to measure the temperature of RTDs.