Desco 19770 Installation guide

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Digital Surface Resistance/Resistivity
Test Kit Operation and Maintenance
Figure 1. Desco Item 19770
Description
The LCD Surface Resistance/Resistivity Test Kit is a
portable instrument designed to measure resistance
between two points (RTT), surface to ground (RTG), and
surface resistivity in accordance with ANSI EOS/ESD
Association Standard S4.1. The unit’s unique Liquid Crystal
Display (LCD) allows the user to easily read measurements
directly from the meter. No interpretation or calculations are
necessary. Per ANSI/ESD S20.20, test equipment is
required to enact Compliance Verification
Plan Requirement - Test equipment shall be selected to
make measurements of appropriate properties of the
technical requirements that are incorporated into the ESD
program plan. This unit is ideally suited for evaluating the
electrical properties of ESD protective work surfaces and
flooring products.
The LCD Surface Resistance/Resistivity Test Kit is NIST
calibrated and is available in three models:
Figure 2. Parallel Resistivity Electrodes on bottom of meter.
The meter also incorporates two parallel probes on the
bottom of the unit which allows surface resistivity
measurements. These parallel electrodes allow for quick
and easy testing of a variety of surfaces and materials,
without the use of 5 pound electrodes. The 5-pound
electrodes (item 50003), and test leads (item 50075) can be
bought separately.
The Test Kit displays a measurement per ESD S4.1-1997
proving the proper electrification period of 15 seconds
during which numerous readings and calculations are
executed. NOTE: Testing in accordance with ESD S4.1-
1997 requires 15 seconds of electrification; in contrast, most
analog type meters display measurements instantaneously.
Recommended Literature
Desco recommends that you read the following standards
from the ESD Association:
ANSI/ESD S20.20 — Development of ESD Control Program
ESD ADV1.0 — Glossary of Terms
ESD S4.1 — Worksurfaces
ANSI EOS/ESD S6.1— Grounding
ANSI ESD S7.1 — Floor Materials
ANSI EOS/ESD S11.11 — Surface Resistivity
These documents can be obtained directly from the ESD
Association, 7902 Turin Rd., Suite 4, Rome, NY 13440-
2069, [phone].
In addition to the Association Standards listed previously,
anyone testing the electrical properties of ESD protective
surfaces should also obtain copies of:
MIL-HDBK 263A EIA-IS-5-A ASTM-F-150
EN 100015 EIA-625
These standards are available from the agencies who
produce them. If you need help in obtaining these
documents, please contact our customer service
department.
Model Description Voltage/Hz
19770 Test Kit 120/50-60
19775 Test Kit 220/50-60
19771 Tester Only 120/50-60
DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: http://www.desco.com
TECHNICAL BULLETIN TB-2024
Made in America

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Inspection
Remove the meter from the carton and
inspect for damage. Each test kit should
include the following:
1 Protective carrying case
1 LCD megohmeter
2 Test leads
2 5-pound electrodes
1 Grounding clip
1 AC adapter/charger
1 Rechargeable battery
Properly store the meter and component
assemblies when not in use. Do not
charge battery unless it is fully
discharged. Doing so will reduce the life
of the battery.
Features
A. Scale: 1/2 inch high digital LCD
display provides easy to read
resistivity/resistance measurements.
Values are expressed with a mantissa
and exponent power. For example, if
the display reads “2.9 E 9”, 2.9 is the
mantissa, 9 is the exponent power; the
reading is 2.9 x 109ohms.
B. Test Button: This button turns on
the power to the meter. The operator
needs to hold the button down for 10-
20 seconds for the unit to make
numerous readings and calculations.
(Testing in accordance with ESD
S4.1-1997 requires 15 seconds of
electrification; in contrast, most analog
type meters display measurements
instantaneously.) When released, the
measured reading will remain illuminated
for at least 10 seconds.
C. Test Range Voltage Switch:
10 Volts for 1x103- 1x1011 ohms
100 Volts for 1x106- 1x1012 ohms
D. Jacks: 2.5mm plugs will fit the
megohmmeter jacks. Banana plugs will
fit the 5 lb. electrodes.
E. AC-Battery Charger Jack:
12 volts DC - 100mA.
F. 9 Volt Battery Compartment.
G. Parallel Electrodes.
Figure 3. Features of the LCD Surface Resistance/Resistivity
Megohmmeter
Figure 4. If the value of the
measurement is below 1000 ohms on
the 10 volt scale or 1x106on the 100
volt scale an “L” will appear on the LCD
display.
Figure 5. If the value of the
measurement is over 5x1012 ohms an
“H” will appear on the LCD display.
Figure 6. A “P” will appear on the LCD
display if there is too much electrical
60Hz noise in the area or if a test is
performed on a high open resistance.
Figure 7. When the unit’s batteries
need recharging a “BAL” will appear on
the LCD display as the meter is being
operated. To maximize the life of the
battery do not recharge until a low
battery “BAL” is displayed.
A
B
E
D
G
C
F
1.7x105S
Item #19770
Chino, CA Canton, MA
DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: http://www.desco.com

TB-2024 Page 3 of 4
Figure 8. Clean before testing.
Cleaning
Work surfaces or materials to be tested should be cleaned
prior to testing to ensure that surface dirt and contamination
do not affect the test results. Periodically clean the built-in
parallel electrodes and the two 5 lb. electrode conductive
rubber probe surfaces. Use solvent-free and silicone-free
cleaners. We recommend using Desco Reztore™ anti-static
surface and mat cleaner (item 10435). Be sure the surface
is dry before testing.
Power Requirements
The meter is powered by a rechargable 9 volt
Nickel/Cadium battery or a special AC to DC adapter. The
adapter is also used to recharge the 9 volt battery.
Surface Resistance Measurements (RTT)
Complies with ESD S4.1
Point to point surface resistance measurements are made
using the meter along with both of the 5 pound electrodes.
This test will determine the resistance between two points,
independent of a groundable point. To perform surface
resistance tests you must first determine what test
procedure you will be using. The test procedure will help
you to determine proper preparation of the material to be
tested and the spacing of the weights. Once testing
parameters are determined you can proceed with the
following instructions:
A. Connect the test leads to the meter by inserting the
banana termination end of a test lead into the 5 lb.
electrode and the 2.5 mm mini phone plug end into the
megohmmeter.
B. Place both electrodes on the material at positions
determined by the procedure selected. Set the meter to the
required test voltage determined by the test procedure and
the resistance of the material. Conductive material 104
ohms or less is usually tested at 10 volts. Dissipative
material is usually tested at 100 volts. If material to be
tested is unknown, it is recommended to first test at 10
volts.
C. Press and hold the red test button for 10-20 seconds
(the unit will be making numerous measurements and
calculations.) The measured resistance value will appear on
the display. This reading is expressed in ohms. You may
want to record the temperature, humidity and test voltage.
Figure 9. Setting up for RTT testing.
Surface-to-Ground Measurements (RTG)
Complies with ESD S4.1
The Surface-to-Ground readings will measure the surface
resistance between selected locations on a work surface
and a groundable point or points. Ground points are usually
in the form of snaps installed on the material so that the
material can be grounded via ground cords. The charge
dissipation rate of all ESD protective materials is related
directly to electrical resistance to ground. When making
Surface-to-Ground measurements, follow this prodedure:
A. Connect one of the 5 pound electrodes to the
megohmmeter using one of the test leads.
Figure 10. Setting up for RTG testing.
B. Using the other lead, connect one end to the
megohmmeter. Insert the grounding clip included with the
test clip onto the banana plug on the other end of the lead.
Now, connect the grounding clip to the groundable point on
the surface to be tested.
DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: http://www.desco.com

TB-2024 Page 4 of 4
DESCO INDUSTRIES INC.
Employee Owned
Battery Life: Nikel/Cadmium - approximately 1
hour
Charge Time: 12 hours
Adapter Output: 12 volt DC - 100mA
Internal Electrodes: Two parallel conductive silicone
rubber replaceable electrodes
External Electrodes: Two 5-pound weighted electrodes,
2.5" in diameter, complies
with EOS/ESD-S4.1
Display: One six character .500" LCD
display
Accuracy: 103- 109= ±15% at 10-90% RH
109- 1011 = ±20% at 10-60% RH
1011 - 1012 = ±30% at 10-50% RH
Meter Weight: 13 oz.
Charger Weight: 11 oz.
Dimensions: 7.5"L x 4"W x 1.75"H
Power Switch: Momentary on. Releasing the
switch will hold and display for
>10 seconds.
C. Position the electrode on the material at the position
specified by the procedure selected. Set the megohmmeter
to the desired test voltage range. Be sure to keep the cords
separated in order to prevent false readings especially
when testing high resistance materials.
D. Press the red test button for 10-20 seconds. The
measured resistance value will appear on the display. This
reading is expressed in ohms. You may want to record the
reading, humidity, temperature and test voltage.
E. Repeat procedure on the other points on the material
under test.
Surface Resistivity Measurements -
Quick Reference
Complies with ANSI EOS/ESD S11.11
A. Firmly place the megohmmeter’s parallel probes on the
surface of the material to be tested, at the position specified
by the procedure selected.
B. Press and hold the red test button for 10-20 seconds.
The measured resistivity value will appear on the display.
This reading is expressed in ohms. You may want to record
ambient temperature and humidity.
Maintenance
Your Surface Resistance Test Kit will require little
maintenance, and there are no user serviceable parts. If
your megohmmeter requires service beyond cleaning the
probes or replacing or recharging the battery, please
contact the factory.
Calibration
The 19770 is calibrated to NIST traceable standards.
Please call our Customer Service Department at 909-627-
8178
(Chino, CA) or 781-821-8370 (Canton, MA) for
details.
In-house calibration can be performed by using 1% resistors
in each of the meter ranges. Simply attach the resistors to
the enclosed cords using grounding clips and recording the
meter display. Keep the cords separated. Adjustments to
the internal resistance pots can be done quite easily.
Request this procedure from the Desco Customer Service
Department.
Specifications
Ranges: 103- 1011 ohms @ 10 Volts
106- 1012 ohms @ 100 Volts
Power Supply: 9 volt rechargeable
Nickel/Cadmium battery and AC
adapter/charger included.
Alkaline battery optional.
Limited Warranty
Desco expressly warrants that for a period of one (1) year from the date
of purchase, Desco Test Kits 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
909-627-8178 (Chino, CA) or 781-
821-8370 (Canton, MA) 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 Desco factory.Warranty
repairs will take approximately two weeks.
If your unit is out of warranty call Customer Service at
909-627-8178
(Chino, CA) or 781-821-8370 (Canton, MA) for a Return Material
Authorization (RMA) and proper shipping instructions and address.
Desco 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 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.
DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]
DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: http://www.desco.com