We are using a DT85 to measure the voltage drop over a high resistance (> 1Mohm) with the aid of an external voltage supply. When we limit the supply to a 3V input and thus the measurements to the 3V range on the data logger the measurements are correct as confirmed by use of a multimeter. We would like to measure at higher voltages to get more accurate readings. When using the attenuator however the measured values are only half of what they should be (as measured with the same multimeter), also at voltage below or at 3V.

I am wondering if this is a setting in the data logger that has to be set or that there is a larger issue?

Hi Roeltersteeg,

When attenuator is enable, the resistance across terminal drop from 10 Mohns to 100 kohms.
We understand that your sensor has high resistance thus having 100 kohms internal resistance will not suitable.

Please keep attentuator disable to maintain reading accuracy.

Best regards,
Rudy Gunawan