Arduino Example: Thermistor Read

[Kristoff2]

Before opening this example, make sure to install the LabVIEW Interface for Arduino.

Description:

This example shows how to read an analog thermistor on the Arduino using the LabVIEW Interface for Arduino.

Tutorial:

1. Make sure you have installed the LabVIEW Interface for Arduino.
2. Open the Thermistor Example VI (search for "Arduino" in the example finder once the toolkit is installed).
3. On the front panel, select the Arduino analog pin you want to read, the units of temperature, and resistance value of the paired resistor.
4. Build the circuit schematic shown on the block diagram.
5. Connect your Arduino to your PC with a USB cable. Optionally you can specify the COM port associated with your Arduino to the VISA resource terminal of the Init.vi to decrease the time require for LabVIEW to connect to the Arduino.
6. Click Run.
7. Vary the temperature of the thermistor and watch the gauge and digital display on the front panel update.

[Diego.Gallegos]

I studied the example about the thermistor on the labview toolkit but i dont understand the "thermistor read" sub vi where it multiplies Vcc by the paired resistance and divided by the voltaje of the thermistor(Vt) and then subtracts it by the paired resistance again. In summary, Vcc*Rp/Vt - Rp = Rt.Looks like a voltaje divider but one of the terms doesn`t match.Can you please explain this to me.

[petr b]

mistake

[Kristoff2]

From Voltage Divider on Wikipedia

              

Where:

R1 = Thermistor

R2 = Paired Resistance

Vin= Vcc

Vout = Analog Read Output

I think it is correct as written for the circuit diagram provided on the block diagram (they grey circle component is the thermistor).

Petrb's solution is the inverse of my original calculation and would make sense if you swapped the Thermistor and the Paired resistor.

Does this make sense?

-Sam K

[Mohsin_Shaikh]

Need Help !! Int. and analog read both Subvi-s detect Arduino at COM16 but when i run complete VI it gives me error 5005. any suggestions ?

[lolol]

How can we add a pid control to this code,and which is considered the input and output?

[Snively]

Hey, quick question.

I'm running the thermistor example VI and have everything wired as in the example wiring diagram using A5 as my analog pin.  When I power the arduino (via USB and external supply, grounds tied) I measure (multimeter) a resistance from A5 to GND of ~14 mV.  In actuality this should be closer to 2.5 V.  The mV reading DOES move up and down with temperature, but it seems like something on the Arduino/Labview is pulling the voltage down very low.

I checked my thermistor on a breadboard while still using the Arduino's 5V and GND but without connecting it to the analog pin and it worked great.

Is Labview doing anything to the analog pin to cause this?  The analog read example vi is behaving similarly.  Thoughts?

Thanks so much for the help.

[giladd]

what is the accuracy of this circuit?
what kind of thermistor does it use?