Desco TB-3086 Technical Bulletin

Full-Time Continuous Monitor
Installation, Operation and Maintenance
Figure 1. Desco Full-Time Continuous Monitor
Description
The Desco Full-Time Continuous Monitor is a single
workstation continuous monitor. It continuously monitors
the wiring of an AC outlet, path-to-ground integrity
of one operator, and the ground plane of one ESD
worksurface. Mounting tabs make it suitable to install
in workbench or equipment settings. The embedded
relay terminal activates when a pass condition is
displayed the monitor and maybe connected to
machines for access control or other devices. Connect
the 19323 Power Relay accessory to control power to
workbenches, hand tools, and other electronic devices
dependent on the Full-Time Continuous Monitor's
status.
The Full-Time Continuous Monitor is designed
with Wave Distortion Technology to provide stable
continuous monitoring of the path-to-ground and
presence of 1 megohm resistance of an operator's wrist
strap. Audio and visual alarms activate (in less than
500 milliseconds) when the operator unintentionally
disconnects from the monitor or the wrist strap
connection points are intermittent. The Full-Time
Continuous Monitor also monitors for a worksurface
path-to-ground of less than 10 megohms and the
integrity of the electrical ground used to by the monitor
All Full-Time Continuous Monitors are calibrated to NIST
standards and include a certificate.
TB-3086 Page 1 of 8
March 2021
TECHNICAL BULLETIN TB-3086
Wave Distortion Technology is the Most Reliable
Technology for the Continuous Monitoring of
Single-Wire (Conductor) Wrist Straps
"Wave Distortion" or vector impedance works by
applying a continuous test voltage of 1.2 volts
peak-to-peak at 1 to 2 microamperes (0.000002
amperes) to the wrist strap that is connected to the
continuous or constant monitor. The test voltage creates
a square wave that the monitor circuit compares to
established patterns. By monitoring the "distortions", or
shape of the square wave, Wave Distortion Technology
determines if the monitored circuit is complete - the
operator is in the circuit and the total equivalent DC
resistance is within specifications. Wave Distortion
Technology produces a very fast alarm time and
minimal false alarms.
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 Full-Time Continuous Monitor and its accessories
are available as the following item numbers:
Item Description
19321 Full-Time Continuous Monitor, with North
America Power Cord
19322 Full-Time Continuous Monitor, with UK Power
Cord
19323 Power Relay, North America
19327 Power Cord, North America
19328 Power Cord, UK
98221 Wave Distortion Monitor Verification Tester
Phone 781-665-1400 Toll
Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
Made in the
United States of America
5 Commonwealth Ave 5 Commonwealth Ave
Woburn, MA 01801 Phone Woburn, MA 01801
781-665-1400 Toll Free
1-800-517-8431