The sensitivities of the individual sensors are adjusted to the same
sensitivity, using the trimming resistors. The resulting sensitivity is indicated on the side of the
CNR 1 's casing. The heater should only be used if a power supply is not a problem, to eliminate
dew and frost deposition. It is not a necessity, and will introduce some measurement errors. Under
most conditions the accuracy that is gained by heating will be larger than the errors that are
introduced by heating. It runs on 12 VDC, 6 VA for dew prevention. Generally, it is suggested to
heat only at night.