Campbell CS110, Инструкция по эксплуатации

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Instruction Manual
11
Figure 5. Parallel-Plate Electric Field Meter Calibration Chamber.
Each CS110 is factory calibrated in the parallel plate calibration fixture depicted
in Figure 5. A linear fit of the calibration data results in a calibration equation in
slope-intercept form expressed as
E = M
parallel_plate
⋅
V + O
parallel_plate
(eq. 3).
The multiplier M
parallel_plate
is a function of the CS110 electrode dimensions and the
feedback capacitor in the charge amplifier. The offset term O
parallel_plate
is due to
unwanted surface charges residing on non-conductive deposits on the electrodes.
The electric field offset of an instrument varies over time because of variations in
surface cleanliness along with charging and discharging processes. Polished 316-
L stainless-steel is used for critical electrode surfaces on the CS110 to minimize
unwanted surface charges. CS110s with clean electrodes have been found to
display electric field offsets
<⏐
30 V/m
⏐
, which has negligible effect on the
determination of M
parallel_plate
because of the
±
15 kV/m range of electric fields used
during factory calibration. Neglecting O
parallel_plate
results in the simplified parallel-
plate calibration equation
E = M
parallel_plate
⋅
V (eq. 4).
The estimated measurement accuracy of M
parallel_plate
for the CS110 calibrated in
the parallel plate electric field calibrator illustrated in Figure 5 is
±
1 %. The
electric field offset of the CS110 can be measured by covering the stator with a
clean Zero Electric Field Cover (PN: 010346). If the resulting zero field reading