TB-6518
Page 2 of 4
DESCO EMIT WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178 • Fax (909) 627-7449
DESCO EMIT EAST
- 90 Hudson Road, Canton, MA 02021-1407 • (781) 821-8370 • Fax (781) 575-0172 • Web Site: DescoEMIT.com
The present reading is held and the word "HOLD"
appears in the display. The rangefinder LEDs go off
during the hold period to conserve battery life. A second
brief click releases the held reading.
CAUTION:
If, as you approach the target, the indicated
field strength begins to exceed 20kV at a distance
greater than 1",
STOP!
This implies that the target
voltage may be high enough to create an arc. Proceed
with caution.
For measurements in excess of 20kV, estimate the
distance to the target and use the following multiplying
factors:
At 4", multiply reading by 2 - 40kV range
At 6.5", multiply reading by 3 - 60kV range
At 8.5", multiply reading by 4 - 80kV range
The LED rangefinder system is calibrated at 1"
distance only.
Figure 3. Taking readings in the “HOLD” mode.
2. Repeat the above for additional measurements.
3. To turn the instrument off, press and hold the HOLD/OFF
button for more than 3 seconds.
Operating Notes:
• The case of the instrument is made of a material which is
sufficiently conductive to provide a grounding path via
the person holding the instrument or a grounded wrist
strap in contact with the case.
• The output jack accepts a standard 3/32" (2.5mm)
monaural phone plug and is provided in order that the
output of the instrument may be connected to an
oscilloscope, strip chart recorder, external meter or
other device. The output voltage at this jack is ±2 volts
for full input (20kV/in. at 1") for high impedance loads
(100 k
S
or greater). It has an impedance of
approximately 100
S
).
The shell of this jack may be used to provide a
"hard ground" connection.
• If you press the on/zero button during operation, the
meter begins the auto zero function and displays the
value. If you do not complete the auto zero operation,
the meter is not correctly zeroed.
• For extended monitoring of materials, a +9 volt power
supply (such as Radio Shack #273-1552) may be
substituted for the battery.
Measurement Accuracy
The accuracy of measurement is dependent on a stable
ground reference and the 1 inch measuring distance as
previously noted. It is also dependent on the “aspect ratio,”
relating the size of the object to be measured to the
measurement distance. This ratio should be at least 3 for
best accuracy, i.e. the object should be at least a 3 inch
square when measuring at a 1 inch distance. Accurate
measurements may be made at other measurement
distances by scaling the meter range and observing the
proper aspect ratio. For example, at a measurement
distance of 3 inches, multiply the meter reading by 3 to give
the range of 0 to 59.97kV. For accuracy, the object being
measured at this distance should be at least a 9 inch
square.
Auditing of Ionization Equipment
with the 50551
Due to its unique measuring circuit the digital fieldmeter will
accurately operate in an ionized air stream or ionized field.
Desco EMIT offers a “Portable Ionization Test Kit” (Item
#50552) designed to facilitate routine auditing and periodic
testing of ionization equipment. The test it si designed to be
used in conuunction with the 50551 meter. The meter and
test kit combination can be used to audit an ionizer's overall
performance. The highly portable test kit allows the user to
make quick and accurate balance level and neutralization
efficiency measurements. The test kit is sold separately as
item #50552. The Portable Ionization Test Kit includes a
slide-on adapter plate, a ±1000V charging unit and a
durable molded carrying case along with the Digital
Fieldmeter.
Figure 4. Auditing ionization equipment with the Digital
Fieldmeter and the Ionization Test Kit.
In order to test ionization equipment to an industry
Thousands
Hundred
Tens
© 2006 DESCO INDUSTRIES INC.
Employee Owned
