USB 6210 themocouple giving wrong readings

[KSagarN]

Hi,

I have the USB 6210 and I am trying to read the temp from a thermocouple.

When I read it when the thermocouple tip isn't in contact with anything, it gives a reading of below 15 degrees celsius. Thats wrong thou as the room temp is about 20-22 here.

I followed the USB 6210 manual on how to connect a thermocouple.

This is a pic of the page.

I followed the floating singal Diff type connection.

For the thermocouple reading vi, I used this example.

http://zone.ni.com/devzone/cda/epd/p/id/4996

Can someone tell me what I am doing wrong?

Thank you.

Message Edited by KSagarN on 02-20-2009 01:55 PM

[KSagarN]

Hi,

I came across this message and was wondering what Brian was suggesting.

http://forums.ni.com/ni/board/message?board.id=150&message.id=1354

what does he mean by configuring CJC by software?

I am new with Labview and was wondering if anyone can help me out.

Thanks

[Jordan F]

The 6210 does not have a built in CJC and will not be able to directly read the temperature from the thermocouple.  To get around this, you need to read an analog voltage and manually scale this voltage (convert the voltage) to temperature.  To create the custom scale you can refer to the document below. 

What Are Custom Scales, and How Do I Use Them?

http://digital.ni.com/public.nsf/allkb/0464919A11C092E386256D800079C3BB?OpenDocument

How Do I Create a Custom Thermocouple In NI-DAQmx?

http://digital.ni.com/public.nsf/allkb/F3AF73201B0E2AB786256F8E006BD181?OpenDocument

The document below shows how to create a CJC virtual channel in software.

How to Create a CJC Virtual Channel for Use with Thermocouple Virtual Channels

http://digital.ni.com/public.nsf/allkb/B0F36EAF0CD5443B862569DD000B311C?OpenDocument