independently monitors the operator and the work surface.
The instant an operator’s wrist strap or cord fails, the
monitor will issue audible and visual alarms alerting the
user of the problem. In the same manner, the unit also
confirms that an electrical discharge path to ground of less
than 500 megohms exists from the ESD protective work
surface. No user adjustment or calibration required.
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. Dual Operator Workstation 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 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, Desco
Charleswater has chosen wave distortion technology for all
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 Workstation
Continuous Monitor will reliably determine if the circuit is
complete.
Wave distortion technology can be referred to as “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.
TB-2084
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Dual Operator Workstation Continuous Monitor
Operation, Installation and Maintenance
Figure 1. Desco Dual Operator Workstation Continuous
Monitor.
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 Desco Dual Operator Workstation Continuous
Monitor continuously monitors the grounding integrity of two
operators, and an ESD protective work surface’s discharge
path to ground. The monitor will provide instantaneous
notification of static control equipment failures, eliminating
the need of costly record keeping. This unit is highly cost
effective as it is designed to monitor any conventional single
conductor wrist strap and ground cord system.
The Dual Operator Workstation Continuous Monitor is
available in two models.
The Dual Operator Workstation Continuous Monitor is an
impedance sensing device designed to monitor body types
from a 5th percentile female to a 95th percentile male. This
range covers a 5 foot tall 90 pound person to a 6 foot 5 inch
250 pound person in any production environment.* The
19208 is powered by a 120 VAC, 60/50 Hz, plug-in
transformer.
No user adjustment required:
The Continuous Monitor is
drift-free and designed to be insensitive to the effects of
squeezing or stretching the coil cord. It requires no user
adjustment or calibration.
The Dual Operator Workstation Continuous Monitor is a
Real Time instrument that ensures that critical ESD
generators in a sensitive area are effectively grounded. It
*NASA Publication 1024-Anthropomorphic Source
Book Volume 1: “Anthropometry for Designers”
Model
Voltage AC
19208
120 Volt
19209
220 Volt
DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178 • Fax (909) 627-7449
DESCO EAST
- 90 Hudson Road, Canton, MA 02021-1407 • (781) 821-8370 • Fax (781) 575-0172 • Web Site: http://www.desco.com
TECHNICAL BULLETIN TB-2084
Made in America
