Can I use USB-6008 Low-Cost Multifunction I/O and NI-DAQmx to record temperature measurements with thermocouples?

[Nick_Diamond]

Hi I am actually a chemical engineering graduate student, and therefore have no training whatsoever on labview. 

A colleague of mine suggested I use a USB-6008 Low-Cost Multifunction I/O and NI-DAQmx to record thermocouple readings. I am using 5 J-type sheathed and grounded thermocouples (1/16'') to measure the temperature of a spray of water. Will this work? Can anybody give me an idea as to how to set this up, or suggest an idea that would work better? Thanks

Regards, 

Nick

[johnsold]

It will not work very well.

You only have 4 differential channels available on the USB-6008. If you configure the device for single ended inputs, you have 8 channels but the only range is +/-10 V. On that range the resolution is about 5 mV. A type J thermocouple generates ~ 50 uV per degree, so that resolution translates to about 100 degrees! Even in differential mode the resolution would be about 10 degrees.

If you want to use the USB-6008 with thermocouples, you will need to add signal conditioning circuits.  Unless you ave an electrical engineering friend to build something for you, the signal conditioner will cost more than the USB-6008.

Lynn

[iamjrr]

There are some cheap thermocouple signal conditioners.

We use these quite a lot in our labs: http://www.analog.com/static/imported-files/data_sheets/AD594_595.pdf

Generally about $12-15 each and provide an output of 10mV/ degC which should be sufficient if your looking for a budget temperature DAQ system.

[Nick_Diamond]

Thank you very much. I am looking into them.