15
depress
CHG.
This function also limits the Static Decay Meter ability to
measure decay times longer than this time out.
8. When the
CUTOFF
threshold selected is reached, the unit will automatically
switch to the
TEST OVER
state, the Sensor Head Shutter will close, and the
Decay Time measurement, in seconds, will be displayed on the
DECAY
TIME
readout. The unit will remain in the
TEST OVER
state until the
ZERO/STBY
or
CHG
button is depressed.
9. To repeat the test measurement, depress the
CHG
button and, when the
SAMPLE CHARGE
meter reads full scale, depress
TEST
. For the greatest
accuracy,, it is recommended that the zero calibration point be checked
between decay time measurements and the
ZERO
control adjusted if
necessary. As noted earlier, calibration of the zero point is always done with
the system in
ZERO/STANDBY
.
NOTE:
For additional information on sample testing, please refer to
Section
4.0 "Testing Hints and Other Tests".
3.3 AUTO
Mode
In this mode, the Model 406D Static Decay Meter will conduct up to 9
measurement cycles automatically, including automatic zero calibration. This
mode cannot be used with samples that have an initial or a residual charge.
3.3.1 Initial Set Up
Follow the procedures outlined in Section 3.1.
3.3.2 Full Scale Calibration
With the unit in
MANUAL
and
ZERO/STANDBY
, zero the
SAMPLE
CHARGE
meter by adjusting the
ZERO
control. Select the
CHARGING
VOLTAGE
polarity by depressing either the
+
or
-
button.
Wait approximately 2 seconds, then set the
CHARGING VOLTAGE
meter to either
+
or
-
5kV using the
HIGH VOLTAGE ADJUST
Control.
Depress the
CHG
button and adjust the
FULL SCALE
calibrate control so
that the
SAMPLE CHARGE
meter reads ±5kV. Unless this adjustment is
properly made
before
the
AUTO
mode is selected, the Automatic Mode
may not function properly. The
FULL SCALE ADJUST
knob should point
approximately to the
NORM
position. For non-planar material, other
settings will apply to achieve a full scale reading.
3.3.3 Sample
Testing
After the unit has been calibrated, select the
AUTO
mode by depressing
the
AUTO/MAN
button. The button will latch in the down position, the
SAMPLE CHARGE
meter will read zero, the unit will return to the
ZERO/STBY
state and the
AUTO
mode readout will be illuminated and
display zero.
