TECHNICAL BULLETIN TB-3062
Digital Surface Resistance Meter Kit
Installation, Operation and Maintenance
•
•
•
Made in the
United States of America
The Surface Resistance Meter Kit (or its Meter) is referenced
and designed to be used to make measurements in
accordance with the test procedures in:
Compliance Verification - ESD TR53 - Resistance
Measurements
Worksurfaces - ANSI/ESD S4.1 Worksurfaces
Floors - ANSI/ESD S7.1- Resistive Characterization of
Materials Floor Materials
• Foot Grounders - ESD SP9.2 - Foot Grounders
Resistive Characterization
Garments - ANSI/ESD STM2.1 Garments
Seating - ANSI/ESD STM12.1- Seating - Resistive
Measurement
Floor/Footwear - ANSI/ESD STM97.1 - Floor Materials
and Footwear- Resistance Measurement in Combination
with a Person
•
•
•
Figure 1. Desco Digital Surface Resistance Meter Kit
Description
The Desco
19787
Digital Surface Resistance Meter Kit is
an instrument designed to measure resistance point-to-point
(Rtt) or surface to ground (Rtg) in accordance with ESD
Association Standard ANSI/ESD S4.1.
Its test functions include:
• Resistance measurement accuracy of ±10%
(±20% for resistance values 1 x 10
11
and greater)
• Resistance range of <1 x 10
3
ohms to >1 x 10
12
ohms
• Under load voltages of 10 and 100 volts ±5%
• Electrification period of approximately 15 seconds
The Digital Surface Resistance Meter also measures ambient
temperature and relative humidity.
The Digital Surface Resistance Meter Kit and its accessories
are available in the following item numbers:
Item
Description
19787
Digital Surface Resistance Meter Kit
19788
Digital Surface Resistance Meter
19783
Shielded Test Leads
50003
Five Pound Electrodes, 1 Pair
50004
Replacement T-Handles for Electrodes, 1 Pair
50005
Concentric Ring Probe
“A Compliance Verification Plan shall be established
to ensure the Organization’s fulfillment of the technical
requirements of the ESD Control Program Plan. Process
monitoring (measurements) shall be conducted in
accordance with a Compliance Verification Plan that
identifies the technical requirements to be verified, the
measurement limits and the frequency at which those
verifications shall occur. The Compliance Verification Plan
shall document the test methods and equipment used for
process monitoring and measurements. If the test methods
used by the Organization differ from any of the standards
referenced in this document, then there must be a tailoring
statement that is documented as part of the ESD Control
Program Plan. Compliance verification records shall be
established and maintained to provide evidence of conformity
to the technical requirements.
The test equipment selected shall be capable of making the
measurements defined in the Compliance Verification Plan.”
(ANSI/ESD S20.20 section 7.3)
Reference Literature
In addition to those noted above:
ANSI/ESD S20.20 - Development of ESD Control Program
ESD ADV1.0 - Glossary of Terms
ANSI/ESD S6.1 Grounding
These documents can be obtained directly from the ESD
Association, 7902 Turin Rd., Suite 4, Rome, NY 13440-2069,
(315) 339-6937 or
www.ESDA.org.
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3062
Page 1 of 8
November 2017
© 2017 DESCO INDUSTRIES, INC.
Employee Owned
Packaging
19787
Digital Surface Resistance Meter Kit
1 Digital Surface Resistance Meter
2 Shielded Test Leads, 5' Length
2 Five Pound Electrodes
2 AA Alkaline Batteries
1 Gator Clip
1 Plastic Carrying Case
1 Certificate of Calibration
Features and Components
A
B
C
D
E
F
G
Figure 2. Desco
19787
Digital Surface Resistance
Meter Kit
19788
Digital Surface Resistance Meter
1 Digital Surface Resistance Meter
2 AA Alkaline Batteries
1 Certificate of Calibration
FRONT VIEW
H
REAR VIEW
Figure 3. Desco
19788
Digital Surface Resistance Meter
Figure 4. Digital Surface Resistance Meter features and
components
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3062
Page 2 of 8
© 2017 DESCO INDUSTRIES, INC.
Employee Owned
A. Test Jacks:
The shielded test leads connect here. The
black test lead’s 3.5mm plug connects into the stereo jack,
and the white test lead’s banana plug connects into the
banana jack.
B. Display:
Temperature, Relative Humidity and Surface
Resistance Mantissa values appear on this display.
When the test button is depressed and the meter is set to
FULL test mode, the following information will display in
sequence:
•
•
•
•
Temperature in degrees Fahrenheit (±10%)
Temperature in degrees Celsius (±10%)
Relative Humidity as a percentage (±10 integers)
Surface Resistance Mantissa (with exponent displayed
via LED, measurement in ohms)
F. Quick Check Button:
When set to FULL, the meter
will cycle through the 15 second period that displays the
temperature and relative humidity before the surface
resistance mantissa is displayed. When set to QUICK, the
meter will skip the 15 second period and immediately display
the measured surface resistance mantissa.
G. Test Button:
Push and hold this button to make a
measurement with the meter. Testing in accordance with
ANSI/ESD S4.1 requires 15 seconds of electrification. These
15 seconds are included when the meter is set to FULL test
mode. The surface resistance mantissa will display on the
meter after temperature and relative humidity measurements
are displayed.
The surface resistance exponent number illuminates
immediately, and the meter first displays the temperature
and relative humidity during a 15 second electrification
period. The mantissa is then displayed at the end of the test
sequence. For example, if the #8 exponent LED illuminates
and the meter displays “7.14”, the measurement is 7.14 x 10
8
ohms or 714,000,000 ohms.
H. Battery Compartment:
Open this compartment to install
the two AA alkaline batteries needed to power the meter.
Replace the batteries once the Function LEDs begin flash.
Surface resistance ohm values are expressed with a
mantissa and exponent (power) of the number. For example,
if the #8 exponent LED illuminates and the meter displays
“7.14”, the measurement is 7.14 x 10
8
ohms or 714,000,000
ohms.
If the measured surface resistance is over 10
12
ohms, “1___”
will appear on the display.
C. Exponent LEDs:
These LEDs indicate the surface
resistance exponent value. They are color coded for quick
checks.
Exponent
<3, 3
4, 5
6, 7, 8
9, 10
Color
Red
Green
Blue
Green
Operation
11, 12, >12 Yellow
Quick Checks
The surface resistance exponent number illuminates
immediately (i.e. 8 = 10
8
ohms or 100,000,000 ohms).
D. Function LEDs:
These LEDs indicate the measurement
type indicated on the display. The surface resistance
mantissa is displayed when either the “10V” or “100V” LED is
illuminated.
These LEDs will flash when the battery voltage drops to
approximately 2 volts. Replace the batteries when this
occurs.
E. Test Voltage Button:
When set to AUTO, the meter will
automatically switch to the appropriate test voltage for the
measured resistance range. The Function LEDs will indicate
the applied test voltage. Material that is 9 x 10
5
ohms or
less should be measured at 10 volts. Material that is 1 x 10
6
ohms or greater should be tested at 100 volts. When the
switch is set to 10V HOLD, the test voltage will be fixed at 10
volts regardless of the measured resistance value.
General Guidelines
• Use both 5 pound electrodes for Rtt measurements.
• Use one 5 pound electrode and connect the black test
lead to ground for Rtg measurements.
• Ensure that the item being measured is electrically
isolated (placed on an insulative surface). The meter will
measure the lowest resistance path.
• Ensure that the test leads are separated and uncrossed
as a best practice.
• When using 5 pound electrodes:
• Place them no closer than 2" from the edge of the
surface being measured
• Place them no closer than 3" to any groundable
point
• Place them about 10" apart from each other for Rtt
measurements of a worksurface
• Place them about 3' apart from each other for Rtt
measurement of a floor
• Preferable electrode placements include:
• Most commonly used area of a surface
• Most worn area
• Center of surface
• Furthest area from a grounded point
• If the surface to be measured has sections (i.e. floor
tiles, garment panels), place the 5 pound electrodes on
different sections for Rtt measurements.
• Clean the material’s surface for Test Lab measurements,
but do not clean the surface for materials that are
already installed. Only clean and re-test the installed
material if failure occurs.
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3062
Page 3 of 8
© 2017 DESCO INDUSTRIES, INC.
Employee Owned
•
Push and hold the Test Button until the surface
resistance mantissa is displayed.
•
Measure Resistance to Ground (Rtg)
Test Procedure in accordance with ANSI/ESD S4.1 section
6.4 Periodic Worksurface Testing:
• Do not clean the surface.
• Remove from the surface only those items that might
interfere with the test.
• ESD sensitive devices shall also be removed.
• Clip the black test lead to a grounded point.
• Use one 5 pound electrode on the other test lead and
place the electrode on the furthest convenient point on
the surface.
• Push and hold the Test Button until the surface
resistance mantissa is displayed.
• Perform additional measurements by placing the
electrode on the most commonly used or worn area. Set
the meter to QUICK test mode to skip the 15 second
period if preferred.
If the measurement is outside acceptable limits, clean the
surface with an ESD cleaner containing no insulative silicone
such as
Reztore™ Antistatic Surface & Mat Cleaner,
and
re-test to determine if the cause of failure is an insulative dirt
layer or the ESD worksurface material.
Perform additional measurements by placing the
electrode on the most commonly used or worn area. Set
the meter to QUICK test mode to skip the 15 second
period if preferred.
If the measurement is outside acceptable limits, clean the
surface with an ESD cleaner containing no insulative silicone
such as
Reztore™ Antistatic Surface & Mat Cleaner,
and
re-test to determine if the cause of failure is an insulative dirt
layer or the ESD worksurface material.
10"
Figure 6. Rtt test setup - set the electrodes about 10"
apart for worksurfaces and about 36" apart for flooring
Reporting and Using Test Results
Different standards have different requirements; however,
follow the requirements as specified in the user’s ESD
control plan. Examples are:
Per ANSI/ESD 4.1 (Worksurfaces), report:
• Rtg maximum and minimum values measured for
resistance-to-ground in ohms
• Rtt maximum and minimum values measured for
point-to-point resistance in ohms
Figure 5. Rtg test setup
Measure Resistance Point-to-Point (Rtt) on the Surface
• Do not clean the surface.
• Remove from the surface only those items that might
interfere with the test.
• ESD sensitive devices shall also be removed.
• Use two 5 pound electrodes and place them on the most
commonly used area of the surface. Ensure that the
electrodes are about 10" apart from each other and 2"
away from any edge and 3" away from any grounded
point.
• Push and hold the Test Button until the surface
resistance mantissa is displayed.
• If the most used area is not obvious, use two points near
the center of the surface.
Per ANSI/ESD 7.1 (Floors), report:
• Rtg all values in ohms for resistance-to-ground
• Rtt all values in ohms for point-to-point resistance
• Voltage level
• Test date
• Temperature
• Relative humidity
• Test equipment used and latest calibration date
Summarize the test data by reporting the minimum,
maximum, median and mean values that were obtained.
Include a diagram showing the approximate electrode
positions and ground connections used.
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3062
Page 4 of 8
© 2017 DESCO INDUSTRIES, INC.
Employee Owned
Frequency of Compliance Verification Testing
NOTE: “The frequency of periodic testing is normally
specified in corporate operating procedures. …The frequency
of testing is driven by the amount of risk exposure that can
occur between tests. For, example, what is the quantity of
product handled between test periods?” (See ESD Handbook
ESD TR20.20)
Per ANNEX A of Compliance Verification ESD TR53 “Test
Frequency, The objective of the periodic test procedures
listed in this document is to identify if significant changes in
ESD equipment and materials performance have occurred
over time. Test frequency limits are not listed in this
document, as each user will need to develop their own set
of test frequencies based on the critical nature of those ESD
sensitive items handled and the risk of failure for the ESD
protective equipment and materials.”
Addition information includes:
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•
•
Worksurface
- at least quarterly (see ESD TR20.20
section 5.3.1.13 Periodic Tests)
Footwear
- “Incoming inspection on a lot sampling basis
should be performed for all static control footwear.” (see
ESD TR20.20 section 5.3.3.4 Testing)
Floor
- “The types of monitoring and type of equipment
are considerations. In some cases, a simple electrical
resistance test with a megohmmeter may suffice. In
others, a static charge generation test may be required.”
(see ESD TR20.20 section 5.3.4.13 Performance
Monitoring)
Seating
- “The recommended electrical resistance
range for seating is less than 1 x 10
9
ohms as tested in
accordance with ANSI/ESD STM 12.1. This value should
be during acceptance testing, installation and periodically
thereafter.” (see ESD TR20.20 section 5.3.5.3 Testing)
Garments
- “To maintain process control, it is imperative
that the garment be tested per ANSI/ESD STM 2.1. The
point-to-point and sleeve-to-sleeve resistance test should
be made.” (see ESD TR20.20 section 5.3.13.3.1.8
Periodic Testing)
Surface Resistivity
Theoretically, Resistivity is 10 times greater than Resistance.
For example, a material that measures 10
7
ohms in surface
resistance should measure 10
8
ohms/square in surface
resistivity.*
Ref: ANSI/ESD STM11.11 section 12.0 Conversion to
Resistivity states, “When it is appropriate to convert a
resistance obtained by this test method to an equivalent
resistivity in ohms per square, multiply the resistance
measurements obtained by this method by 10. The
conversion factor of 10 is derived from the geometry of the
electrode assembly.”
*Note: Although STM11.11 uses ohms/square, per ESD
TR20.20, the correct unit of measure for resistivity is just
ohms.
Product Qualification Test Lab Test Procedure Guideline
For test lab use of ESD Worksurfaces, Floor Materials,
Footwear, Garments or Seating, the best advice is to follow
the test methods in applicable ESD Association documents
which include details such as:
• Cleaning (For example per S4.1, “The test specimens
and electrodes shall be cleaned twice with a minimum
70% isopropanol-water solution using a clean, low-linting
cloth each time). Allow to the material to dry.
• Environmental chamber (For example per S4.1, control
relative humidity to 12 ±3% relative humidity and 50 ±5%
relative humidity and temperature to 23 ±1°C)
• Specimen support surface (For example per S4.1,
greater than 1 x 10
12
ohms such as PMMA, PTFE or
polycarbonate)
• Specimen Pre-Conditioning (For example per S4.1, at 23
±1°C; 3 specimens at 12 ±3% relative humidity for up to
72 hours minimum, and 3 specimens at 50 ±5% relative
humidity for up to 72 hours minimum)
• Reporting Test Results: For example per S4.1 Reporting
Test Results, report:
• Minimum, median and maximum readings for both
resistance-to-groundable point and point-to-point
resistance in ohms at low relative humidity
• Minimum, median and maximum readings for both
resistance-to-groundable point and point-to-point
resistance in ohms at moderate relative humidity
• Temperature
• Relative humidity
• Actual duration of conditioning
• Test equipment used and latest calibration date
•
•
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3062
Page 5 of 8
© 2017 DESCO INDUSTRIES, INC.
Employee Owned
