Campbell CS110, Инструкция по эксплуатации, Страница: 23 / 86

Instruction Manual
13
Figure 7. NIST Calibration Certificate
Careful removal and replacement of the stator on the CS110 does
not invalidate the factory derived M
parallel_plate
of a given unit.
However, switching stators with another unit or accidentally
bending the stator, shutter or sense electrodes invalidates the factory
parallel-plate calibration because of possible electrode dimensional
changes.
5.2 Site Correction
As previously mentioned, each CS110 is factory calibrated in a parallel plate
calibration fixture resulting in calibration equation 4. However, when monitoring
the Earth’s electric field, equation 4 is valid only if the instrument aperture is
mounted flush with the Earth’s surface and upward-facing. Yet for permanent
outdoor measurements of electric field, a flush-mounted and upward-facing
orientation is problematic because of dirt, bird droppings, rain, etc., collecting on
the sense electrodes and fouling the measurement. Consequently, a downward
facing and elevated configuration as illustrated in Figure 8 is recommended for
long-term field applications.
NOTE