5
Front panel indicator lights indicate the cutoff threshold selected, operating state
and on/off status of the high voltage. The sample is contained in a special
Faraday Cage, which includes a patented Electrostatic Sensor (ETS Patent No.
3824454) that enables the system to make a true electrostatic (non-contact)
measurement of the charge on the sample. A fail-safe interlock system is
employed which automatically discharges the test sample and/or prevents
charging of the test sample when the Faraday Cage hood is raised. The safety
interlock system also prevents the sample from being charged if the cage is not
properly connected to the Control Unit. The unit may be switched to operate
from either 100, 110, 220 or 240 VAC, 50-60 Hz.
2.2 Controls
All controls for operation of the Static Decay Meter are located on the front panel
of the unit. Four types of controls are used: two position (latching) push button
switches, momentary push button switches, rotary controls and a ten (10)
position rotary switch. The state of the
POWER
ON/OFF
switch and
MAN/AUTO
switch are indicated by panel markings above and/or below each switch. The
state in the DOWN position (button
latched in) is marked BELOW each switch.
When the
POWER ON/OFF
button is UP, the
power is OFF. When the
MAN/AUTO
button is UP, the unit is in the
MANUAL
mode.
2.2.1 Main AC POWER ON/OFF
This self-latching (push-on-push off) switch controls the AC power input to
the unit. When placed in the down position, the AC power will be
ON
and
the front panel indicators will be illuminated.
2.2.2 MAN/AUTO Mode Select
This self-latching switch, when in the
AUTO
(down) position puts the unit
in the
AUTO
mode. In this mode, the
AUTO
mode numeric indicator will
be illuminated.
2.2.3 Adjustment
Controls
2.2.3.1
ZERO
This control is functional in the
MANUAL
mode only. It is used to
set the
SAMPLE CHARGE
meter reading to zero when the system
is in the
ZERO/STANDBY
mode. Since the accuracy of the decay
time measurement is highly dependent on the initial setting of the
zero point, it should be set as accurately as possible and re-
checked prior to each test run.
2.2.3.2
FULL SCALE
This control is used to adjust the
SAMPLE CHARGE
meter to full
scale (a reading of ±5kV) when the system is in the
MANUAL
mode and the operate state has been set to
CHARGE
.
