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TECHNICAL BULLETIN TB-2oasa
SPI Ground Gard 5 / 5.5
Operation, Installation, and Maintenance
Made in the
United states of America
SPI
SPl-20686
94391
Figure 1.
SP/
Ground Gard items SP/-20686 and 94391.
Description
The
SPl-20686
and
94391
are wrist strap and ground
monitoring devices for the e
l
ectronics work station. It is
designed to constantly monitor two single wire wrist
straps using a Remote Operator Module for each user.
These units provide continuous monitoring of:
• One or two users wearing a wrist strap
• Ground (Verification between electrical and ESD
ground)
Lead
i
ng companies use continuous monitors as a cost
effective component in satisfying the paragraph 6.1.3
Complicance Verification Plan requirements of ANSI/
ESD S20.20. The SPl-20686 and 94391 Continuous
Monitors provide continuous monitoring of two operators
and also functions to ensure connection to ground. If the
monitor, using capacitance technology, detects improper
grounding of the operator, the monitor will
i
ssue an
audible alarm along with an illuminated red LED to notify
the user of a problem.
Many customers are eliminating periodic testing and are
utilizing continuous monitoring to better ensure that their
products were manufactured in an ESD controlled
environment. Continuous monitoring is superior to
periodic testing. "While effective at the time of testing,
wrist strap checker use is periodic. The failure of a wrist
strap between checks may expose products to
damage from electrostatic charge. If the wrist strap
system is checked at the beginning of a shift and
subsequently fails, then an entire shift's work could be
suspect." (ESD TR 12-1 Section 1.0 Survey of Constant
Monitors for Wrist Straps)
Continuous Monitors eliminate 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
Paragraph 6.2.2.2 test logging requ
i
rements. Per ESD-
S1 .1 paragraph 6.1.3 Frequency of Functional Test
i
ng
"Daily (Wrist Strap) testing may be omitted if constant
monitoring is used."
"Because wrist straps have a finite life, it is important to
deve
l
op a test frequency that will guarantee integrity of
the system. Typical test programs recommend that wrist
straps that are used daily should be tested daily.
However, if the products that are being produced are
of such value that knowledge of a continuous, reliable
ground is needed, and then continuous monitoring
shou
l
d be considered or even required.
"
(ESD Handbook
TR 20.20 section 5.3.2.4.4)
The SPl-20686 and 94391 will alarm if preset values are
exceeded for capacitance
,
high resist and ground loss
conditions. The grounding system is redundant and will
still provide a limited grounding even if the utility ground
is lost and the system is in an alarm state.
Capacitance Type Continuous Monitors
"These types of monitors are used with a single wire
(sing
l
e conductor) wrist strap. Monitors in this category
operate by
"
sensing
"
body capacitance. For capaci
tance monitors, an AC voltage is applied to the wrist
strap through the single conductor ground cord. Due to
capacitive coupling of the person to ground based on the
surroundings, the monitor will indicate either good or bad
depending on the manual adjustment or preset
tolerance. Since a capacitor or capacitive network
responds like a resistor to an AC current, the single
conductor wrist strap monitor only provides an estimate
of the wrist strap wearer's apparent resistance.
"
(ESD Handbook TR 20.20 section 5.3.9.2 Types of
Continuous Monitors)
Packaging
Item SPl-20686
1 Ground Gard 5.5 Monitor
2
94340
Remote Operator Modules
2 10 Foot Phone Cords
1 12 Foot Ground Cord
1 Velcro
®
Set
4 Screws
1 Power Adapter - 3 Prong, 12 Volts
Item 94391
1 Groud Gard 5 Monitor
2
94340
Remote Operator Modules
1 Power Adapter - 2 Prong, 12 Volts
2 Remote Operator Cables
1 Black Ground Cord
1 Green ground Cord
2 Velcro
®
Strips
4 Screws
1 Certificate of Calibration
TB-20686
February 2016 Page 1 of 3
@ 2016 DESCO NDUSTRIES NC.
E...,,_Owned
