AC RTD sample with simulated device

[newbieeng]

hi all,

I am studying on DAQ samples in labview 2009, I have no DAQ device but I simulated NI 9188 and NI 9214 (thermocouple). I want to run "acq RTD sample.vi" with these simulated devices but when I run the program it shows error "Possible reasons: Device to which the sensor is attached does not have an available internal excitation source. Select another device with an available internal excitation source or supply external excitation.". However, in the web it is said that NI 9188 and NI 9214 are available for real-time measurements. What is wrong with this?

[Jacob_R]

Hello,

The reason you are seeing that error is that you are using an resistance temperature detector which require excitation voltage and not a standard thermocouple.

The 9214 is only used for thermocouples.

If you want to use that RTD example, try simulating the 9219.

https://www.ni.com/en-us/shop/model/ni-9219.html

Good luck,

[newbieeng]

Thank you Jacob. I will check the links that you noted but I confused a little... Is it not possible to work with 9214 for real-time measurements?

[johnsold · Accepted solution]

What Jacob was saying is that the 9214 is not designed to work with RTD sensors.  An RTD is a resistor which changes value with temperature.  A thermocouple generates a voltage proportional to the temperature difference  between the junctions.  A measurement system for thermocouples needs to measure voltage and often compensates for the cold junction temperature.  A measurement system for RTDs needs to measure resistance which usually involves supplying a current and then measuring the voltage drop.  The 9214 does not have a current supply circuit for the RTD.

From the specificatioons for the 9214 it appears that it will work with the Real-Time operating system.

Lynn

[newbieeng]

Thank you Lynn. Now, I understood it clearly.