What are the requirements after changing to a longer length sensor cable?
You need to perform sensor cable compensation per this procedure: Sensor Cable Compensation As noted in the instruction manual, this instrument measures the capacitance of the sensor (in the form of attenuation in decibels) from which it computes the dewpoint. At very low dewpoints the capacitance is small enough to be in the same order of magnitude as a long coaxial cable. Thus the measurement circuit must be compensated for the capacitance of the sensor cable. Instruments which are sold with a cable are already compensated at the factory and should not be compensated again. However if a new cable is added, the following procedure should be used for compensation A. Disconnect the sensor from the cable by unplugging the BNC connector. Keep the cable connected to the instrument. B. Prepare a means by which the BNC connector at the end of the cable could be reliably shorted (using a jumper clip etc.), do not attempt to short at the instrument screw terminals as this approach will not acc
