Convert RTD Resistance to RTD Temperature

[ShalimarA]

Overview

This VI is an altered version of the 'Convert RTD Reading' VI that accepts a resistance rather than an RTD Voltage and Iex value

Description

When reading from an RTD value via DAQmx, you can configure the output to give a resistance value (eg in a 4-wire configuration), which can be mapped to a temperature. The 'Convert RTD Reading' VI is a suitable way of converting RTD readings to temperature readings, however this VI accepts RTD Voltage and an excitation current (Iex) as the inputs, to determine the RTD Temperature in degrees Celsius. As resistance is a more intuitive output from an RTD, this VI accepts resistance as an input in order to determine the temperature in degrees Celsius.

The VI simply takes in to consideration that the RTD resistance is the RTD Voltage divided by Iex.

Requirements

Software:

LabVIEW 8.6 or compatible

Hardware:

NI DAQ or RIO hardware producing RTD readings

Steps to Execute Code

If the RTD reading is read from the host, simply output the value of RTD resistance in to 'Converter.vi' and attach an indicator to display the results.

If the RTD reading is from the FPGA, the conversion needs to be done on the host. Simply access the FPGA VI via Open FPGA VI Reference and an FPGA Read/Write Control, as shown below.

Additional Information or References

LabVIEW 2012 Help: Convert RTD Reading VI

**This document has been updated to meet the current required format for the NI Code Exchange.**

[David_Staab]

This VI returns NaN for inputs above a certain threshold. What are the boundary conditions on its inputs? Should it be modified to handle NaN?