Put the thermocouple under the maximum themperature you expect it to be. Measure the voltage across (Vth) the thermocouple with a DMM. The minimum input range for the 6008 is 1Volt so you need an amplifier
of gain 1/Vth to use all available bits of resolution. You will need to convert voltage to temperature units in software. You will need the coefficients of the thermocouple to do that. Note that your measurements will be noisy as this
device is not ideal for thermocouples.
KostasB
National Instruments UK
