This document explains using a low-cost thermistor to measure temperature with your National Instruments myDAQ in LabVIEW. The data will be acquired using the DAQ Assistant that is installed into LabVIEW with the NI DAQmx driver and converted to a temperature using basic programming in LabVIEW.
The user interface we created both shows the current temperature measurement taken as well as plotting the values over time on a waveform chart. Temperature Chart stores previous values so that you can see the change in values over time.
Figure 3: LabVIEW Front Panel
Coding Strategy:
In LabVIEW we need to measure the resistance signal coming from the thermistor from 100Ω to 100kΩ. This value is converted to a temperature using the polynomial equation from the thermistor specifications referenced at the end of this document. Finally, we will output the result to a numeric indicator and a temperature chart on the front panel.
Figure 4: Coding Block Diagram
The LabVIEW block diagram looks very similar to the coding block diagram
Figure 5: LabVIEW 2009 Block Diagram
(The attached LabVIEW code snippet can be dragged-and-dropped to a LabVIEW block diagram, use attached PNG file. After locating the PNG file, just drag the file icon onto a blank block diagram, as if you were dragging the file onto your desktop.)
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