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-3078
Page 1 of 6
© 2019 DESCO INDUSTRIES INC
Employee Owned
Zero Volt Monitor
Installation, Operation and Maintenance
Description
The Desco 19668 Zero Volt Monitor is a dual
workstation continuous monitor. It continuously monitors
the path-to-ground integrity of two operators and two
ESD worksurfaces. It also will indicate if voltage greater
than ±1.25 V is induced onto the operator. Audio
and visual alarms activate in failure situations. The
Desco Zero Volt Monitor provides stable continuous
monitoring of the path-to-ground and presence of two
1 megohm resistors of an operator’s dual-wire wrist
strap. Audio and visual alarms activate (in less than 500
milliseconds) when the wrist strap connection points
are intermittent. The Desco Zero Volt Monitor also
monitors for a worksurface path-to-ground less than 3.5
megohms. All Desco Zero Volt Monitors are calibrated
to NIST standards and include a certificate. A calibration
unit is available to preform compliance verification at the
workbench without taking the monitor out of service.
Desco Zero Volt Monitor Technology
The Desco Zero Volt Monitor uses electrical loop
resistance technology. Dual test signals are placed
onto each of the dual-wire wrist strap's conductors
to negate finger-tip voltage. Resistance is monitored
with a continuous split test signal sent through both
conductors, across the skin of the operator, and
returning to the monitor through the opposite conductor.
Desco Zero Volt Monitors determine that the operator’s
path-to-ground is between the 2 megohms lower limit
and 10 megohms upper limit. Additionally, the Desco
Zero Volt Monitor determines if voltage greater than
±1.25 V has accumulated on the operator.
March 2019
ANSI/ESD S20.20 section 7.3 states “Compliance
verification records shall be established and maintained
to provide evidence of conformity to the technical
requirements.” Per ANSI/ESD S1.1 Annex A.3 Daily
(wrist strap system) testing may be omitted if constant
monitoring used.” Per ESD Handbook ESD TR 20.20
section 5.3.2.4.4 “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 should be considered or even required.”
The Zero Volt Monitor and its accessories are available
in the following item numbers:
Item
Description
19668
Zero Volt Monitor
50524
Limit Comparator
50529
Replacement Operator Remote Kit, Black
50530
Replacement Operator Remote Cable, Black
50531
Replacement Operator Remote Kit, White
50532
Replacement Operator Remote Cable, White
50533
Replacement Operator Remote
50534
Replacement Hardware Kit
19262
Replacement Power Adapter, 12 VDC
Packaging
1 Zero Volt Monitor
1 Power Adapter, 12 VDC, with interchangeable plugs
(North America, UK/Asia, Europe)
2 Operator Remotes
1 Operator Remote Cable, Black
1 Operator Remote Cable, White
1 Monitor Ground Cord, Green
1 Mat Monitor Cord, Black
1 Mat Monitor Cord, White
2 Mat Ground Cords, Green
1 Hardware Kit
1 Certificate of Calibration
Made in the
United States of America
TECHNICAL BULLETIN TB-3078
Figure 1. Desco 19668 Zero Volt Monitor
