NI 9214 won't measure multiple channels

[nc61]

I have the NI 9214 DAQ with 16 channels, and I am taking measurements (voltage) using NI MAX. When I have only one analog input, the measurements work just fine. However, when I plug in a second, both values float (leaving me with useless, fluctuating data). I am taking differential measurements for a thermocouple, so I didn't think I had to wire anything to the common ground. All I have are +/- going into port 10 and +/- going into port 11 and the measurements fall apart. I also tried chaning the ports and the same thing occurs. 

[chaka1234]

Hi nc61,

Since you are taking data from a thermocouple, you can create a thermocouple task as you can see in this image:

After you've configured the channels that you want to use for acquiring data, you can click on Connection Diagram Tab and it will show you how to connect your thermocouple correctly:

Best,

Carmen C.