ESD SYSTEMS MiniMeg 41256 Installation guide

Installation
Remove the meter from the carton and
inspect for damage. Each unit should
be fully charged and includes:
1 MiniMeg Pocket Megohmmeter
1 Surface-to-Ground, cord assembly
1 Installed 9V battery
Properly store the meter and its
component assemblies when not in
use.
Operation
The MiniMeg will perform Surface
and Surface-to-Ground resistance
measurements. Work surfaces and
materials to be tested should be
cleaned prior to testing to ensure that
surface dirt and contamination do not
affect results. It is recommended that
non-silicone based cleaners such as
ESD Systems.com ‘REZTORE’
Surface and Mat Cleaner be used for
regular cleaning of ESD protective
work surfaces. When non-ESD
surfaces are being used, ‘Reztore’
Topical Antistat is recommended for
eliminating static charge generation.
The MiniMeg has not been designed
to meet ESD S4.1 test equipment
requirements and therefore
measurements obtained with this
device may not agree with
measurements taken according to the
ESD S4.1 test procedure. This test
instrument is intended for use only as
an auxiliary tool for monitoring
surface resistance performance. If you
are interested in obtaining a meter
which does meet all the test
equipment requirements of ESD S4.1,
we recommend our model 41290
Surface Resistance Test Kit. For more
information on this product ask for
tech brief PS-2111.
PS-2078 7/05 Page 1 of 4
MiniMeg™ Pocket Megohmmeter
Operation and Maintenance
Figure 1. 41256 MiniMeg Pocket Megohmmeter
The ESD Systems.com MiniMeg
Pocket Megohmmeter is a portable
test instrument designed for measuring
both surface and surface-to-ground
resistance of static dissipative and
conductive materials. Seven color-
coded LEDs, read from right to left,
easily identify static dissipative and
conductive ranges. The MiniMeg will
test materials with surface resistivity
of 1x105- 1x1010 Ohms/sq. This test
instrument is ideally suited for Quality
Control and Field Service personnel as
well as for use in routine auditing of
your ESD protective materials. The
MiniMeg features simple one-button
operation and a 9V battery for
constant use and maximum portability.
This state-of-the-art, auto-ranging
instrument provides top performance,
yet weighs only six ounces. The high-
impact plastic case ensures durability
despite the meter’s light weight.
Tech Brief
Figure 2. Cleaning the work surface
before testing.
MiniMeg ITEM # 41256
MARLBORO, MA
Made in America
© 2005 DESCO INDUSTRIES INC.
Employee Owned
ESD Systems.com • 432 Northboro Road Central, Marlboro, MA 01752-3170 • [phone] • Fax [phone] • Web Site: http://www.esdsystems.com

Surface-to-Ground
Measurements (RTG)
The Surface-to-Ground feature is best
used when expected results are less
than 106Ohms, and when residual
voltages can be removed from the test
surface. Residual voltages may cause
the two upper range LEDs to light,
resulting in a false reading.
When the Surface-to-Ground cord is
plugged in, voltage is diverted from
the center electrode to the cord in
order to measure resistance. When
making Surface-to-Ground tests,
follow these procedures:
A. Check battery operation by
depressing the white button. The red
“On” lamp will indicate that the unit
is functioning properly.
B. Plug the Surface-to-Ground cord
into the left side of the meter.
Figure 4. Installing Surface-to-Ground
cord assembly.
C. Place the MiniMeg on the test
surface.
D. Connect the test cord to the
ground-point for the surface.
E. Press the white button. The LEDs
will indicate the test results.
PS-2078 Page 2 of 4
Surface and Surface-to-Ground
resistance readings are indicated by
the series of LEDs on the face of the
meter. The LEDs are read from right
to left as follows:
1. RED – >1010, Meter is on
and battery is
functioning
2. RED – Less than 1 x 1010
3. GREEN – Less than 1 x 109
4. GREEN – Less than 1 x 108
5. GREEN – Less than 1 x 107
6. YELLOW – Less than 1 x 106
7. YELLOW – Less than 1 x 105
Each LED indicates one order of
magnitude of resistance. If the test
surface is conductive to less than 105
Ohms/sq., all the LEDs will be lit. If it
is neither conductive nor static
dissipative, only the red “On” LED
will be lit.
Surface Resistivity
Measurements (RTT)
Surface resistivity measurements are
made using only the meter without the
cord assembly. When the white button
is depressed a test voltage of 9 VDC is
applied to the meter’s center electrode.
The second resistivity electrode will
supply the resistance bridge and
provide the measurement. To perform
surface resistivity tests, follow these
simple instructions:
A. Check battery operation by
depressing the white button on the
center of the meter. The red “On”
lamp at the far right should light to
indicate that the unit is functioning
properly.
B. Place the meter on the surface
being tested. All three electrodes
should make contact with the surface.
C. Press the white button. The surface
resistance will be indicated by the
number of LEDs which light up. The
more lights illuminated, the greater the
conductivity of the surface.
Figure 5. Measuring Surface-to-Ground
resistance.
F. Unplug the cord when testing is
finished.
Battery Operation
Battery function is automatically
checked by the unit when the meter is
turned on. If the battery voltage drops
below 8 VDC, the red LED on the far
right of the meter will not light,
indicating a “low battery” condition.
Replace battery with a new 9V
alkaline battery.
Maintenance
Your MiniMeg will require very little
maintenance, and there are few user-
serviceable parts. If your meter
requires service beyond the simple
procedures described below please
contact the factory.
Electrode Cleaning
To assure accurate measurements the
electrodes should be kept clean. A
thorough cleaning at least every 3
months is recommended. The
following is the recommended
cleaning procedure:
1. Carefully remove the electrodes
from their snap-jacks using a screw
driver or other blunt flat bladed object.
Avoid scratching or bending
electrodes.
Figure 3. Measuring surface resistivity.
WORK SURFACE
GROUND POINT
MiniMeg
© 2005 DESCO INDUSTRIES INC.
Employee Owned
ESD Systems.com • 432 Northboro Road Central, Marlboro, MA 01752-3170 • [phone] • Fax [phone] • Web Site: http://www.esdsystems.com

PS-2078 Page 3 of 4
Figure 6. Cleaning the electrodes.
2. Clean both the snap stud and the
electrodes with a cotton swab soaked
in isopropyl alcohol. Check the rubber
centers for wear - the rubber should
form a convex spot on the bottom of
the electrode. If the rubber is worn,
replace electrodes. Otherwise snap the
clean electrodes back onto the meter.
Electrode Replacement
The ESD Systems.com 41258 is an
electrode replacement kit for the
MiniMeg. Included with each kit are 3
plated electrodes and 3 conductive
rubber electrodes. Replacement
electrodes must be installed correctly
to insure proper operation. Follow
these instructions carefully:
A. Remove the old electrodes by
placing a screwdriver under the lip of
the cap and prying up to unsnap.
B. Remove the conductive rubber
piece from inside the snap stud.
C. Clean the new electrode assemblies
with isopropyl alcohol.
D. Insert a new conductive rubber
electrode into a new snap socket, with
the widest end down. Be sure the
rubber is pressed in all the way.
E. Carefully trim the rubber electrode
leaving 1/8” exposed above the
socket.
F. Remove the rubber electrode and
invert it (wide end up).
G. Snap on a new electrode socket
over the rubber electrode.
H. The rubber electrode should be
protruding slightly through the hole in
the socket. If not, give the socket a
slight twist until the rubber is exposed.
Figure 7. Replacing the electrodes.
Once you have replaced the
electrodes, you may wish to make a
quick calibration check (see
Calibration Section) to assure that the
electrodes are operative.
Theory of Operation
The MiniMeg measures resistance by
setting up a bridge between two
precision 1% resistors of known value
and the surface tested, of unknown
value. When the white button is
depressed a test voltage of 9 VDC is
applied to the meter’s center electrode
or ground cord, depending on the test
being performed. One of the bottom
electrodes on the outside of the meter
supplies the resistance bridge. The test
voltage resulting from the bridge is
compared to reference voltages
established by six trimming
potentiometers. Two integrated
circuits are configured as comparators
to check the voltage from the bridge
against the potentiometers. Based on
the setting of each potentiometer, the
appropriate LED is lit.
SNAP SOCKET
CONDUCTIVE RUBBER
SNAP STUD
NEW SOCKET
ELECTRODE
NEW RUBBER
CONDUCTIVE
Specifications
Sensitivity Range
Surface Resistivity Less than 1010
Ohms/sq
Surface-to-Ground Less than 109
Ohms
LED Key (from right to left)
1. Red >1010, Meter On, and
Battery OK
2. Green <1010 Static Dissipative
3. Green <109 Static Dissipative
4. Green <108Static Dissipative
5. Green <107Static Dissipative
6. Yellow <106
7. Yellow <105Conductive
Test Sample Size 3" x 1-1/2" or
larger
General Characteristics
Power Supply 9 volt alkaline
battery
(included)
Test Voltage Nominal 9 volts
Electrodes Steel and
conductive
rubber
Temperature Range
Operating 40°F to 120°F
(10°C to 40°C)
Storage 42°F to 110°F
(-15°C to +60°C)
© 2005 DESCO INDUSTRIES INC.
Employee Owned
ESD Systems.com • 432 Northboro Road Central, Marlboro, MA 01752-3170 • [phone] • Fax [phone] • Web Site: http://www.esdsystems.com

PS-2078 Page 4 of 4
Limited Warranty
ESD Systems.com expressly warrants
that for a period of one (1) year from the
date of purchase, our Mini Megs will be
free of defects in material (parts) and
workmanship (labor). Within the
warranty period, the unit will be tested
repaired or replaced at our option, free of
charge. Call Customer Service at 508-
485-7390 for a Return Material
Authorization (RMA) and proper
shipping instructions and address. You
should 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 ESD
Systems.com factory. Warranty repairs
will take approximately two weeks.
If your unit is out of warranty, ESD
Systems.com will quote repair charges
necessary to bring your unit to factory
standards. Call Customer Service at
508-485-7390 for a Return Material
Authorization (RMA) and proper
shipping instructions and address.
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 ESD Systems.com 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.
Relative Humidity 0% to 99% (non
condensing)
Operation Resistance bridge
Readout Seven LEDs
Resolution One order of
magnitude
Accuracy ±10% all, except
±20% 109, 1010
Repeatability ±3%
Weight 6 ounces
Dimensions 4" x 2.5" x 1.75"
Calibration
The 41256 is calibrated to NIST
traceable standards. Any MiniMeg
may be returned to the factory for
calibration. Contact our Customer
Service Department at [phone]
for a Return Material Authorization.
Written Purchase Orders are required
for calibration services.
A check on the function of the
MiniMeg can be performed with the
following procedure. You will need
1% resistors of the following values:
100K, 1M, 10M, 100M, 1G and 10G
ohms. These precision resistors will be
placed across the two electrodes on
the bottom of the meter (see Figure 8).
A. Place the MiniMeg on an insulator
(e.g. Teflon or glass) and press the
white test button. Only the first red
LED on the right, marked “On”
should be illuminated. If this LED
fails to light, the battery should be
replaced before proceeding.
B. Place the 10G ohm resistor across
the middle electrode and the side
electrode as illustrated in Figure 8.
Press the test button. The second LED
should light. Be sure not to contact the
leads or the buttons as your body’s
resistance will affect the readings.
Figure 8. Calibration of the MiniMeg
C. Continue this process with each
consecutive resistor, checking to make
sure the appropriate LEDs are
illuminated. If all resistors check
properly, the unit’s calibration is
verified.
Adjustment
Unauthorized servicing or
modifications to the MiniMeg will
void the product warranty. Servicing
should only be performed by the
factory. See warranty section for repair
charges.
RESISTOR
ELECTRODE
Visit our online
library of Tech Briefs:
http://www.esdsystems.com/
432 NORTHBORO ROAD CENTRAL
MARLBORO, MA 01752-3170
PHONE [phone]
FAX [phone]
© 2005 DESCO INDUSTRIES INC.
Employee Owned