PS-2062
Page 2 of 4
© 2005 DESCO INDUSTRIES INC.
Employee Owned
2. ZERO THE INSTRUMENT -
Make connection between the
Adapter Plate Assembly and the
Digital Fieldmeter case either
through your finger or a test lead.
Face the Fieldmeter away from
charged objects and press the
ON/ZERO button. Hold until the
display reads zero. The instrument
may also be zeroed by pointing it
toward a known grounded surface
(such as the palm of the opposite
hand) and depressing the ON/ZERO
button. Although you must be
careful not to contact the recessed
sensor plate, the amount of spacing
between the instrument and the
target is not critical when zeroing the
instrument.
NOTE: The 42721 has a conductive
case that provides a ground
reference for the measuring circuit.
For accurate measurements it is
necessary that the person holding
the meter be properly grounded.
3. TAKE A MEASUREMENT -
Locate the meter in an ionized
environment at the appropriate
distance from the device under test
(typically 12"). The static field
displayed is the actual balance of the
ionizer or voltage offset.
NOTE:
When testing pulsed ionizer systems,
the voltage displayed is constantly
changing. This pulse rate may be
faster than the display update rate of
the fieldmeter, therefore the
displayed voltage is an average of
the actual voltage. This average
reading is more accurate than
analog style meters which only
display positive or negative values.
AUTO SHUTDOWN TIMER
During normaloperation (not during
ZERO) a blinking decimal point
indicates the AUTO SHUTDOWN
TIMER is enabled. If the AUTO
SHUTDOWN TIMER is disabled
the decimal point will be on
continuously.
Holding down the ZERO button,
while unit is ON, for less than 3
seconds resets the AUTO
SHUTDOWN TIMER (if enabled).
The AUTO SHUTDOWN TIMER is
enabled or disabled by turning on the
unit and keeping the ON/ZERO
button pressed then toggling the
HOLD/OFF button. Enable/disable
of the AUTO SHUTDOWN TIMER
is indicated by the decimal point:
DP on
=
timer on, DP off
=
timer off.
AUTO SHUTDOWN TIMER state
is maintained during power off.
AUTO SHUTDOWN TIMER can be
continually toggled as long as the
ON/ZERO button remains pressed,
up to 20 seconds, after which the
unit will turn off. A blinking decimal
point indicates the AUTO
SHUTDOWN TIMER is active.
During the last minute before power
off ALL annunicators will blink at a
fast rate. Pressing any button will
reset the timer. Timeout is nominally
15 minutes.
Taking Discharge Measurements
In order to verify that an ionizer is
operating properly it is also
important that its ability to neutralize
or discharge static electricity is
measured. The following procedure
will measure an ionizer's discharge
time.
1. OPERATING THE
CHARGING UNIT -
The Charger
has a momentary push-button that
turns on the power to the unit.
Holding the button down supplies
power to the output terminals.
2. OUTPUT CONTACTS -
Two
output contacts are provided on the
Charger. They are connected to an
internal power source. When one
contact is connected to ground the
other contact will provide a charge
of the indicated polarity. The
Charger is designed so that an
operator can press the power button
and touch an output contact,
simultaneously with the fingers of
the same hand.
Figure 2. Installing the Isolated Plate
Assembly on the 42721 Digital
Fieldmeter
Figure 4. Taking a balance
measurement.
