ESD SYSTEMS SPI Ground Gard 3 Plus Service manual

The Parking Snap features provides a means for the
operator to disconnect wrist strap cord when normally
leaving work area without audible alarm sounding. It also
provides a means of wrist strap storage.
ADVANTAGES OF CONTINUOUS MONITORING
OVER PERIODIC TESTING
Many customers are eliminating periodic testing and are
utilizing continuous monitoring to better ensure that their
products were manufactured in an ESD protected
environment. Full time continuous monitoring is superior to
periodic or pulsed testing, and can save a significant
amount of money in testing costs and rejected product.
Periodic testing detects failures after ESD susceptible
products have been manufactured. The costs of dealing
with the resulting catastrophic or latent defects can be
considerable. Ground Gard 3 Plus eliminates the need for
users to test wrist straps and log the results; by their
function, these monitors satisfy the ISO 9000 and
ANSI/ESD S20.20 test logging. ANSI/ESD S20.20
Paragraph 6.2.2.2 Personnel Grounding Guidance states “A
log should be maintained which verifies that personnel have
tested their personal grounding devices.” Per ESD-S1.1
Paragraph 6.1.3 “Daily (wrist strap system) testing may be
omitted if constant monitoring is used.”
WAVE DISTORTION DETECTION TECHNOLOGY
PROVIDES TRUE 100% CONTINUOUS MONITORING
From all the technical alternatives available, SPI Westek
has chosen wave distortion technology for many of its
Continuous Monitor product offerings. Wave distortion
circuitry monitors current/voltage phase shifts and provides
true 100% continuous monitoring. Electrical current will lead
voltage at various points due to the combinations of
resistance and capacitive reactance. By monitoring these
“distortions” or phase shifts, the wave distortion Ground
Gard 3 Plus will reliably determine if the circuit is complete.
Wave distortion technology can be referred to “vector
impedance monitoring”. This description is valid as the
wave distortion technology measures the impedance at the
monitored banana jack and looks for changes in either the
capacitance or resistance of the circuit which includes the
wrist strap and its wearer. It uses filtering and time domain
sampling to filter out false signals caused by voltage offsets,
60 Hz fields and other electro-magnetic and electrostatic
interference.
In normal factory environments, and with persons whose
capacitance with respect to ground is within design limits (5
feet tall 90 pound person to 6 foot 5 inch 250 pound
person), the Ground Gard 3 Plus cannot be “fooled”. It will
provide a reliable alarm only when the wrist strap becomes
dysfunctional or unsafe according to accepted industry
standards. The Ground Gard 3 Plus is drift-free and
designed to be insensitive to the effects of squeezing or
stretching the coil cord.
TB-5534 December 2008 Page 1 of 3
Ground Gard 3 Plus
Operation, Installation, and Maintenance
Figure 1. SPI Ground Gard 3 Plus
Description
Leading companies use continuous monitors as a cost
effective component in satisfying the paragraph 6.1.3
Compliance Verification Plan requirements of ANSI/ESD
S20.20. The SPI Westek Ground Gard 3 Plus is designed
to mount on equipment where worksurface monitoring is
not required. It continuously monitors the integrity of one
operator. The Monitor will provide virtually instantaneous
notification of static control equipment failures, eliminating
the need of periodic testing and costly record keeping. This
unit is highly cost effective as it is designed to monitor any
conventional single wire wrist strap and ground cord
system. There are no additional wires to connect and its
small package and mounting tabs with holes make it
highly suitable to install on most any equipment or
work bench surface. In addition, optional mounting is
available using provided adhesive-backed velcro strips.
Using either mounting method makes the Ground Gard 3
Plus suitable for most any machinery or workbench even in
hard to reach locations.
The SPI Ground Gard 3 Plus is available in two models.
The Ground Gard 3 Plus is a real time instrument that
ensures that critical ESD generators in a sensitive area are
effectively grounded. The instant an operator’s wrist strap
or cord fails, the monitor will issue audible and visual
(LEDs) alarms alerting the user and supervisor of the
problem.
Model Voltage AC Calibration
94341 120 NIST
94342 220 NIST
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
TECHNICAL BULLETIN TB-5534
Made in America
© 2008 DESCO INDUSTRIES INC.
Employee Owned

ADVANTAGES OF WAVE DISTORTION AND SINGLE-
WIRE TECHNOLOGY
The SPI Ground Gard 3 Plus allows the use of any
standard, single-wire wrist strap and coil cord. The
monitor/wrist strap/cord system life-cycle costs are by far
lower than alternative systems which require expensive &
fragile dual-wire cords and special wrist straps. Dual-wire
cords are expensive and are the weak link of the system,
the most likely component to need replacement. Over a five
year period, this can make the dual-wire system three to
five times as expensive as a system utilizing single-wire
wrist straps and cords. See Calibration (page 3) to minimize
life-cycle costs.
The dictionary defines constant as uniform and unchanging,
and continuous as uninterrupted. Nonetheless, some dual-
wire resistance monitors utilize a pulsed test current and do
not really provide continuous monitoring. For example,
during each 2.2 second pulse cycle of a leading “constant”
resistive monitor, electrical current is pulsed for only 0.2
seconds followed by an unmonitored interval of 2 seconds.
This leaves the user/wrist strap unmonitored for over 90%
of each cycle. Damaging static charges can easily occur in
the portion of the time in between the pulses. The off period
of 2 seconds equals 2 billion nanoseconds, and “it takes
only about 25 volts applied for 100 nanoseconds to blow
most memories or microprocessors”.* The dual-wire system
does not reliably meet all industry specifications, as the
cords do not meet the EOS/ESD S-1.0 paragraph 4.1.6,
1 to 5 pound “breakaway force” requirement for operator
safety.
By using the reliable wave distortion technology to
determine if the circuit is complete, there are no false
alarms. There is no need to adjust or tune the monitor to a
specific user or installation. The miniscule amount of
electrical current (less than 1 volt coil cord signal) required
to generate the waveform has never caused reported skin
irritation and is extremely safe for use in voltage sensitive
applications such as disk drive manufacturing.
Installation
Remove the monitor from its packaging and inspect for any
shipping damage. Included with each Ground Gard 3 Plus
should be:
1 120 VAC transformer
2 Mounting screws
1 Adhesive-backed Velcro strip
Figure 2. Installation of Ground Gard 3 Plus on the side of a
machine.
The Ground Gard 3 Plus has a variety of mounting options.
It can be installed under a work bench where the LEDs are
easily visible. It can also be installed on a surface of a
machine, oven, laminate, or other equipment. The mounting
tabs with holes facilitate easy mounting of the unit.
A convenient 120 VAC outlet should be located and tested
for proper wiring and grounding. We recommend SPI
Westek Item 94380 AC Outlet Analyzer to verify integrity of
building ground point.
Plug the transformer into the outlet and connect the output
plug into the back side of the monitor.
Operation
When the Ground Gard 3 Plus is installed, the monitor’s red
Operator LEDs should be on.†
Figure 3. Example of continuous monitoring of an operator
using the Ground Gard 3 Plus.
TB-5534 Page 2 of 3
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
*1981 article by Donald E. Frank - Electrical Overstress /
Electronic Discharge Symposium Proceedings
© 2008 DESCO INDUSTRIES INC.
Employee Owned
†The monitor takes 6 seconds to activate its alarm circuitry when it is first
plugged in.

• The AC adapter must include the ground reference on the
barrel of the output plug.
• The AC adapter therefore supplies the monitor with
ground.
• This monitor simplifies the work area because no other
wiring is needed.
TO USE THE MONITOR:
1. Plug a wrist strap cord, not attached to the wristband,
into the monitored jack on the front of the unit. This will
activate the monitor, but will allow you 8 seconds before the
audible alarm circuit activates.
2. Snap the cord to the wristband and slip it on your wrist (it
should fit snugly). This should silence the audio and cause
the LEDs to switch from red to green. If this does not
happen, check the coil cord for continuity or damage.
Examine your wrist and ensure that it has a secure fit. If you
have dry skin, use antistatic hand lotion such as SPI
Westek’s Reztore™ ESD Hand Lotion, Item No. 96790.
When leaving the area, a person can take the coil cord
along or leave it attached to the monitor. In either case, the
audio alarm will only sound for about eight seconds.
PARK SNAP
The audible alarm is designed to alert both operator and
supervisor. The Park Snap feature provides a means for an
operator to disconnect when normally leaving the work
area, without the audible alarm sounding, and it provides a
means of wrist cord storage (visual red LED will illuminate).
By the operator touching the Park Snap, the audible alarm
is disabled for about 8-10 seconds. The operator can
remove the wrist strap cord and attach socket and cord to
Park Snap for storage. Note when the cord is removed from
the Park Snap, in order to reactivate the audible alarm,
operator must re-connect cord to wristband within 8-10
seconds. At this point user should check the visual (LED)
alarm to make sure it is green (pass).
Specifications:
Operating Voltage
94341 120VAC, 50-60 Hz
94342 220VAC, 50-60 Hz
Response time to alarm <50mS
Operating Temperature 0 - 40°C
Size 2.77"L x 2.07"W x .710"H
Maintenance and Calibration
The Ground Gard 3 Plus is solid state and designed to be
maintenance free. The 94341/94342 is calibrated to NIST
traceable standards. There are no user adjustments
neccesary. Because of the wave distortion sensing nature of
the test circuit, special equipment is required for calibration.
We recommend that calibration be performed using the SPI
#94385 Continuous Monitor Calibration Unit. The
Calibration Unit is a most important product which allows
the customer to perform NIST traceable calibration on
TB-5534 Page 3 of 3
ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com
Limited Warranty
SPI expressly warrants that for a period of one (1) year from
the date of purchase SPI Ground Gard 3 Plus will be free of
defects in material (parts) and workmanship (labor). Within
the warranty period, a credit for purchase of replacement SPI
Continuous Monitors, or, at SPI’s option, the ground Gard 3
Plus 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 one year life times the
original unit purchase price. Call Customer Service at
909-
664-9986
for Return Material Authorization (RMA) and proper
shipping instructions and address. 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 SPI factory. Warranty replacements will take
approximately two weeks.
If your unit is out of warranty, SPI will quote repair charges
necessary to bring your unit up to factory standards. Call
Customer Service at
909-664-9986 f or 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 SPI 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.
continuous monitors. The #94385 is designed to be used
on the shop floor at the workstation, virtually eliminating
downtime, verifying that the continuous monitor is operating
within tolerances. Per ANSI/ESD S20.20 Paragraph 6.2.2.2
Personnel Grounding Guidance, “Personnel should check
constant monitoring devices (when used) to ensure that
they are functional and operating before ESDS products
are handled. In addition, constant monitoring devices
should be functionally checked periodically to ensure that
they are operating as designed.”
© 2008 DESCO INDUSTRIES INC.
Employee Owned