8
2.2.7 AUTO
MODE
These controls provide for programming the unit in the
AUTO
mode and
are functional only when the
AUTO/MAN
button is in the
AUTO
(down)
position.
2.2.7.1.
TESTS
This 10-position rotary switch selects the number of tests to be
conducted. It should be set when the system is in the
ZERO/STBY
state prior to the start of the automatic test sequence. If the switch
is set to zero, the unit will not go into the
TEST
mode when the
CHG
button is depressed, but will remain in either
TEST OVER
or
ZERO/STBY
.
2.2.7.2.
INTERVAL
This continuously variable control is used to select the time interval
between the completion of one test and the start of the next (time
sample is grounded). The interval time may be set to any value
from about 1 second, when the control is in the
MIN
position, to
about 25 seconds, when the control is in the
MAX
position. When
the pointer on the
INTERVAL
knob is set to
5
, the interval will be
about 5 seconds, a convenient interval time for most testing.
During the interval time, the
DECAY TIME
display will hold and
display the decay time of the last test and the
AUTO
mode counter
will display the number of the test run just completed.
2.3 Displays and Meters
Three types of indicators are used in the unit. Analog meters indicate voltage
and charge levels, multicolored point source LED indicators display test status,
cutoff threshold and high voltage presence information, and a LED numeric
readout displays the decay time and the
AUTO
mode test sequence number.
2.3.1 Meters
2.3.1.1
SAMPLE CHARGE
Meter
This analog meter is part of the Electrostatic Voltmeter sub-system
in the Static Decay Meter. It indicates the true relative charge level
on the test sample. The zero (center scale) position is used in the
MAN
mode to calibrate the system for offsets and thermal drift that
can occur. The ±5kV points on the
SAMPLE CHARGE
meter scale
are used to calibrate the system to the full charge level on the test
sample. The meter also provides the operator with information
about the presence or absence of initial static charges on the test
sample.
