ESD SYSTEMS SPI Westek 95420 User manual

TB-5516 December 2008 Page 1 of 4
Digital Hand-Held Static Fieldmeter
Operation and Maintenance
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.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.
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.
Figure 1. 95420 Digital Static Fieldmeter
Description
The SPI Westek 95420 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-5516
© 2008 DESCO INDUSTRIES INC.
Employee Owned

TB-5516 Page 2 of 4
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
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.
AUTO SHUTDOWN TIMER
During normal operation (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.
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, the object being measured at this
distance should be at least a 9 inch square.
Auditing of Ionization Equipment
with the 95420
Due to its unique measuring circuit the digital fieldmeter will
accurately operate in an ionized air stream or ionized field.
SPI Westek offers a “Portable Ionization Test Kit” (Item
#94056) designed to facilitate routine auditing and periodic
testing of ionization equipment. The test it si designed to be
used in conuunction with the 95420 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 #94056. 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.
CHINO, CA
Thousands
Hundred
Tens
© 2008 DESCO INDUSTRIES INC.
Employee Owned

TB-5516 Page 3 of 4
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
Figure 4. Auditing ionization equipment with the Digital
Fieldmeter and the Ionization Test Kit.
In order to test ionization equipment to an industry 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 95420 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 SPI Westek 95420 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 95422 Charging Plate to be installed first)
The Personal HBM Test Fixture (SPI Westek Item Number
95421) turns your model 95420 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
© 2008 DESCO INDUSTRIES INC.
Employee Owned

TB-5516 Page 4 of 4
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
Limited Warranty
SPI Westek expressly warrants that for a period of one (1) year from the date of
purchase, SPI Westek Static Fieldmeters will be free of defects in material (parts)
and workmanship (labor). Within the warranty period, the product will be tested,
repaired, or replaced at Desco’s option, free of charge. Call our Customer Service
Department at
909-664-9986 for a Return Material Authorization (RMA) and
proper shipping instructions and address. Include a copy of your original packing
slip, invoice, or other proof of purchase date. Any unit under warranty should be
shipped prepaid to the SPI Westek factory. Warranty repairs will take approximately
two weeks.
If your unit is out of warranty call Customer Service at
909-664-9986 for a Return
Material Authorization (RMA) and proper shipping instructions and address. SPI
Westek 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 SPI Westek 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.
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.
Figure 6. Installing HBM Test Fixture on 95420 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 95421 HBM Test Fixture and 95422 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.
© 2008 DESCO INDUSTRIES INC.
Employee Owned
B. Insert screw from
the back of 95421
HBM Test Fixture
A. Slide 95420 Static
Fieldmeter down into
95421 HBM Test Fixture.
NOTE: 95422 Charging
Plate is required to use
the HBM Test Fixture.