Hi achesterton,
Yes, what you ask is possible. If you want to determine the resistance vs temperature variation of the temperature sensor on channel 2, you can do this to within the accuracy of the measurement setup/method that you are intending to use (which will include, among other factors, the uncertainty of the PT-100 sensor + data Logger). What you would need to do is apply a reasonably linear stepped change in the temperature of the environment for both sensors, while logging the data as temperture versus resistance over the test temperature range.
First, I would recommend running through the guided Tour of Our PicoLog software (which can be found under the help menu) to familiarize yourself with it's operation. You can then set the channel for the PT100 to 4-wire PT100, and the unkown sensor to 2-wire and Resistance 0.10K, in the Edit PT104 Channel window (which you can get to by double clicking on a channel, in PicoLog). Then finally you can create a data file and start the data recording process in PicoLog while you increment the temperature of your test envvironement.
For highest accuracy i would recommend looking at our guide to "Improving the accuracy of temperature measurements" here:
https://www.picotech.com/library/applic ... asurements. Then, you should use a well controlled environment (preferably a homogenous liquid bath, with minimal thermal gradients, or failing that, an air heated environment that is draft excluded, such as an oven, and precise enough temperature control, with a long enough dwell at the measurement points).
Regards,
Gerry