It is not that the temperature references (CJC sensors) are unstable it is that they are inside the unit behind the connectors. Therefore, when measuring temperature it is wise to connect the thermocouples (TC’s) and wait 30 minutes for the connectors and the TC wire to assume the same temperature. Because there is a soak time to the CJC sensor it recommended that the unit be kept away from vents that may blow on the units causing immediate temperature change to the wires but not to the connector. With this in mind, it also recommended that the Continuous Calibration be used, which is a setting on the Acquisition Configuration dialog. Without Continuous Calibration the temperature will drift over time due to the temperature of the electronics.