LabVIEW interface with Arduino is not displaying data

[mikoloko]

Hello,

I am building a temperature controlled chamber and trying to display in LabVIEW the temperature data from an arduino Uno microcontroller. I have downloaded the LIFA kit as well as the 'Arduino Thermistor Read' VI (attached). When I run the arduino code, the TX and RX on the board are flashing meaning that data is being transfered and received; however, LabVIEW does not display any data and I am not seeeing any error message. Here are some info:

-LabVIEW 2012

-Visa Implementation version 4.0

- baud rate 9600 in both arduino and VI. I also tried 115200 with no result

- # define commandlenght 15 in the arduino code

Any ideas?

[hrh1818]

One possibility is you haven't told the VI what COM port to use.  I don't have access to Labview 2012 but with Labviwew 2010 with this example you need to manually set the COM port.

To manually set the COM port

Open the block diagram.

On the left side double click on the Arduino Init sub VI.

This brings up a LIFA Front Panel.

Enter the value for the COM port you are using with LIFA in the VISA Source control.

Save the VI.

The baud rare for the front panel must be 115200 to match  LIFA's 115200 baud rate.

Run The VI

I ran the Thermistor Read.VI.  It works.

hrh1818

[mikoloko]

The come port is correct because I do not get any connection error. The baud rate is 115200. The only thing I changed was the supply voltage which was 3.3V instead of 5V. I did made the voltage change in the VI

[hrh1818]

Can you run the Analog Read Pin.VI ? 

hrh1818

[Ryton]

It might be a stupid question, but did you connect the thermistor & the paired reference resistor correctly (in series, with the ground at the resistor side) and are your measuring the voltage drop over the thermistor?

Also, measure the resistance (Ohm) of the paired resistance using a DMM, and enter the actual value in the thermistor-read VI.

Or, as the previous poster proposed: Try to just read out the pin voltage value & do the calculations yourself (or copy from the VI). (Since the internals of the Read Thermistor VI contains a regular read analogue pin to read out voltage)

Good luck!

[MIKEMEN]

Well, when I run the circuit using only the arduino, I get the temperature as well as the thermistor resistance displayed. But as soon as I connect it to LabVIEW, I get nothing displayed on the front panel.

[hrh1818]

Thus statement "But as soon as I connect it to LabVIEW, I get nothing displayed on the front panel." brings up questions?  Do you mean you didn't reload LIFA after running the Arduino code?   What VI are you using when connct to Labview?

hrh1818