Desco EMIT TB-6518 User manual

TB-6518 12/06 Page 1 of 4
Digital Hand-Held Static Field Meter
Operation and Maintenance
DESCO EMIT WEST - 3651 WalnutAvenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EMIT EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: DescoEMIT.com
Operation
ZEROING THE METER
1. The meter needs only to be zeroed at the time you first
use the instrument. It will maintain this value until the
battery is changed.
2. Press the ON/ZERO button and release. The LCD
display is activated and LED rangefinder lights begin to
flash.
3. Ground the operator by using a wrist strap or a
footgrounding device. You can also ground the unit
directly via a ground cord. The case of the instrument is
conductive and is the reference for the measurement.
4. 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.
Figure 2. Zeroing the meter.
TAKING READINGS
1. Point the sensor plate toward the target and move to a
spacing of one inch from sensor plate to target. Use the
LED rangefinder to determine this distance. The two
LEDs appear to form a stationary (not moving) circle on
the target at one inch. Note the meter reading. A source
with a negative polarity shows a minus (-) sign in the
display. A positive source will display no sign.
To hold the reading, click the HOLD/OFF button briefly.
Figure 1. 50551 Digital Static Fieldmeter
Description
The Desco EMIT 50551 is a high quality, portable non-
contacting static fieldmeter which produces consistently
accurate readings with ease and provides years of trouble-
free operation. It indicates surface voltage and polarity on
objects up to ±20kV at a spacing of one inch with an
accuracy of 5% of the displayed value. It is chopper-
stabilized for use under almost any conditions including
ionized environments. Also featured are a push-button auto-
zero and a push-button hold function. A unique flashing LED
rangefinder system provides accurate positioning of the
meter from the target.
Its accuracy is dependent upon four factors:
• Grounding of the meter via a ground cord or a grounded
operator.
• The instrument must be properly zeroed.
• The distance from the front edge of the case to the target
or surface under examination must be accurately defined.
• The target must be large relative to the measurement
distance. It should be at least 5" x 5" for true accuracy.
Inspection
Remove the fieldmeter from the carton and inspect for
damage. Included with each unit should be:
1 carrying case
1 9V alkaline battery
Made in America
TECHNICAL BULLETIN TB-6518
© 2006 DESCO INDUSTRIES INC.
Employee Owned

TB-6518 Page 2 of 4
DESCO EMIT WEST - 3651 WalnutAvenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EMIT EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • 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 kSor greater). It has an impedance of
approximately 100S).
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

TB-6518 Page 3 of 4
DESCO EMIT WEST - 3651 WalnutAvenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EMIT EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: DescoEMIT.com
recognized standard, we recommend the test procedure
published by the ESD Association as Standard 3.1. This
standard may be obtained from the ESD Association, 7902
Turin Road, Suite 4, Rome, NY 13440-2069, [phone].
Maintenance
BATTERY REPLACEMENT
The unit should be off while replacing the battery. Normal
battery life is about 40 hours of use. Replace the battery
when the "BAT" indicator appears in the display above the
"HOLD" indicator position for more than an instant or
change at least once a year. Dead battery voltage is
approximately 7.2 volts.
Figure 5. Replacing batteries.
Replacement type is Eveready #216 or equivalent NEMA
1604. An alkaline type is recommended where longest
service life is important. Remove the battery when storing
the instrument for an extended period of time.
NOTE: After you change the battery you will need to re-
zero the meter.
CLEANING
If the 50551 is used in a dirty or dusty environment, it may
be necessary to clean the sensor to ensure proper
operation.
Foreign materials which may enter the aperture associated
with the input electrode can generate undesired signals,
offset or drift, thereby impairing the accuracy and utility of
the instrument. It is imperative that the area around the
aperture be kept scrupulously clean at all times. This can
best be done by proper care, handling and storage of the
instrument. Loose dust or other particulate matter may
simply be blown away with low pressure instrument grade
air.
More severe contamination may be removed by spraying or
flushing with the least practical amount of clean technical
grade isopropyl alcohol. Stand with instrument on end and
allow to dry thoroughly for several hours. Cleaning with any
solvent should NOT be done on a routine basis.
Calibration
The Desco EMIT 50551 is calibrated prior to shipment to
NIST traceable standards. Re-calibration should be
performed annually unless the instrument has been
tampered with or repaired, or more frequent calibration is
specified by company policy or by contract. Calibration of
the Digital Field Meter should only be performed by the
factory. Contact our Customer Service Department for
details.
Recommended Reading
SEMI E43-95, RECOMMENDED PRACTICE FOR
MEASURING STATIC CHARGE ON OBJECTS AND
SURFACES. Published by Semiconductor Equipment
Materials International (SEMI), Mountain View, CA, (650)
964-5111.
Specifications
Display: 3 1/2 digits, 0.4" digit height LCD
Response: <1 sec., 10% to 90% equivalent
to 5Hz output
Range: ± 0.00 to ± 19.99 kV/inch (25mm)
Accuracy: ± 5% of displayed value, ± 3 counts (LSD)
Environment: 0 - 50°C at 85% RH (non- condensing)
Output: 2.5mm phone jack/plug, ± 2 volts for full
input (2V/20kV/in.)
Battery: 9 volt, NEMA 1604, alkaline recommended
Accessories: Carrying case and technical bulletin
included
Charged Plate Adapter available as an
optional accessory for testing air ionizers
Personal HBM Test Fixture
(Requires the 50554 Charging Plate to be installed first)
The Personal HBM Test Fixture (Desco EMIT Item Number
50554) turns your model 50551 Digital Field Meter into a
Human Body Model tribo-electric charging tester. This kit
will allow you to measure electrical charges generated on
the human body while walking or moving across an
insulative or conductive surface. It has been specially
designed to measure static charges produced by walking
across substrates such as carpeting, vinyl floor tile, and
sealed concrete. It can also be used to detect charge
generation on conductive surfaces such as conductive or
dissipative floor tiles and carpeting. An ESD technician
may also use this tool to verify proper grounding between a
conductive or dissipative floor surface and a person
wearing personal grounding devices such as foot
grounders. The amount (or size) of the charge generated
will vary from one human body to another. Other factors
such as humidity, contamination between the foot and
flooring surface, as well as human body capacitance will
also affect the amount of charge generated.
© 2006 DESCO INDUSTRIES INC.
Employee Owned

TB-6518 Page 4 of 4
DESCO EMIT WEST - 3651 WalnutAvenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EMIT EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: DescoEMIT.com
Limited Warranty
Desco EMIT expressly warrants that for a period of five (5) years from the
date of purchase, Desco EMIT Static Field Meters will be free of defects in
material (parts) and workmanship (labor). Within the warranty period, a credit
for purchase of replacement Desco EMIT products, or, at Desco EMIT's
option, the product will be repaired or replaced free of charge. If product
credit is issued, the amount will be calculated by multiplying the unused
portion of the expected five year life times the original unit purchase price.
Call our Customer Service Department at 909-627-8178 (Chino, CA) or 781-
821-8370 (Canton, MA) for a Return Material Authorization (RMA) and proper
shipping instructions and address. Please include a copy of your original
packing slip, invoice, or other proof of date of purchase. Any unit under
warranty should be shipped prepaid to the Desco EMIT factory. Warranty
replacements will take approximately two weeks.
If your unit is out of warranty, call our Customer Service Department at 909-
627-8178 (Chino, CA) or 01892 665313 (Crowborough, U.K.) for a Return
Material Authorization (RMA) and proper shipping instructions and address.
Desco EMIT will quote repair charges necessary to bring your unit up to
factory standards.
Warranty Exclusions
THE FOREGOING EXPRESS WARRANTY IS MADE IN LIEU OF ALL OTHER
PRODUCT WARRANTIES, EXPRESSED AND IMPLIED, INCLUDING
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE WHICH
ARE SPECIFICALLY DISCLAIMED. The express warranty will not apply to defects
or damage due to accidents, neglect, misuse, alterations, operator error, or failure
to properly maintain, clean or repair products.
Limit of Liability
In no event will Desco EMIT or any seller be responsible or liable for any injury,
loss or damage, direct or consequential, arising out of the use of or the inability to
use the product. Before using, users shall determine the suitability of the product
for their intended use, and users assume all risk and liability whatsoever in
connection therewith.
Figure 6. Installing HBM Test Fixture on 50551 Digital Field
Meter
INSTALLATION AND REMOVAL
The test fixture is stored in the Survey Kit with the Digital
Field Meter installed, ready for use. Or, you may purchase
the 50553 HBM Test Fixture and 50554 Charging Plate
separately if you don’t have a Survey Kit. If the fixture
needs to be removed to allow use of the Field Meter alone,
follow steps A and B of the diagram. The ground cord is
located underneath the test fixture in the Survey Kit. To
obtain the desired result, the ground cord must be installed
onto the Field Meter and attached to a utility or common
ground point.
METHOD OF OPERATION
In order to obtain the desired test results, the meter must be
properly grounded as stated in the Installation and Removal
section. Once installed on the Field Meter, the Test Fixture
itself is isolated from the meter case and ground and should
remain that way.
Cradle the Test Fixture in the palm of your hand. Once the
meter is grounded and you are standing on the substrate to
be tested, simply walk around, shuffle your feet or raise a
foot, to determine if the combination of footwear and
substrate produces an electrical charge. If an electrical
charge is generated and induced onto the human body, the
Test Fixture will transfer that charge onto the Field Meter,
and the amount of the charge will be registered. If it is
necessary to record the amount of charge, you can save
Figure 7. Using the HBM Test Fixture to measure charges
on the body.
the result by simply pressing the Hold button on the front of
the Field Meter, and pressing the button with an insulated
object. This test can be done regardless of the type of
footwear or substrate combination. Other items in your
ESD Control Program may also be tested such as
conductive or dissipative chairs. Simply sit in the chair on
the desired substrate and move the chair back and forth to
determine if the chair and human body combination
produces and electrical charge.
B. Insert screw from
the back of 50554
HBM Test Fixture
A. Slide 50551Static
Fieldmeter down into
19448 HBM Test Fixture.
NOTE: 50554 Charging
Plate is required to use
the HBM Test Fixture.
© 2006 DESCO INDUSTRIES INC.
Employee Owned