TECHNICAL BULLETIN TB-3086
Full-Time Continuous Monitor
Installation, Operation and Maintenance
Made in the
United States of America
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.
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 on the monitor and can be 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.
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
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-3086 Page 1 of 8
December 2021
© 2021 DESCO INDUSTRIES INC
Employee Owned
Packaging
19321 Full-Time Continuous Monitor
1 Full-Time Continuous Monitor
1 Mat Monitor Cord (White)
1 Countersunk Washer
1 Flat Head Screw, 6-32 x 1/4"
2 Pan-Head Screws, #6 x 3/8"
1 Dual Lock Fastener Set, 2" Length
1 Power Cord with North American Plug
1 Certificate of Calibration
19322 Full-Time Continuous Monitor
1 Full-Time Continuous Monitor
1 Mat Monitor Cord (White)
1 Countersunk Washer
1 Flat Head Screw, 6-32 x 1/4"
2 Pan-Head Screws, #6 x 3/8"
1 Dual Lock Fastener Set, 2" Length
1 10mm Interchangeable Park Snap
1 10mm Operator Jack Adapter
1 Power Cord with UK Plug
1 Certificate of Calibration
Figure 2. Desco 19321 Full-Time Continuous Monitor
packaging contents
19323 Remote Alarm
1 Power Relay
1 Interface Cable
1 Power Cord with North American Plug
Figure 3. Desco 19322 Full-Time Continuous Monitor
packaging contents
Figure 4. Desco 19323 Power Relay packaging contents
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-3086 Page 2 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Features and Components
C. Operator LEDs: Illuminates green when the
operator is properly grounded. Illuminates solid red and
audible alarm sounds when the operator is not properly
grounded.
Full-Time Continuous Monitor
D. Mat LEDs: Illuminates green when the worksurface
is properly grounded. Illuminates red and audible alarm
sounds when the worksurface is not properly grounded.
A
B
C
C
D
D
E
E
F
G
H
I
J
K
Figure 5. Full-Time Continuous Monitor features and
components
A. Park Snap: Allows the operator to disconnect (and
park) a wrist strap when leaving the workstation, without
creating a false alarm. Touch the park snap or park
switch, and the monitor's audible alarm will disable for
approximately 8 seconds. Use this time to disconnect
the wrist cord from the wristband, and attach it to the
park snap or remove the banana plug from the jack.
Upon returning to the workstation and disconnecting
the wrist cord from the park snap, the operator has
approximately 8 seconds to reconnect the wrist cord to
a worn wristband before activating the alarm.
B. Monitored Operator Jack: Insert the single-wire
wrist cord here to monitor the operator's connection to
ground.
E. Ground LEDs: Illuminates green when the AC outlet
is properly wired and its path to equipment ground via
the equipment ground conductor is intact. Illuminates
red and audible alarm sounds when the AC outlet is not
properly wired and its path to equipment ground via the
equipment ground conductor is broken.
F. Park Switch: Allows the operator to disconnect (and
park) a wrist strap when leaving the workstation, without
creating a false alarm. Touch the park snap or park
switch, and the monitor's audible alarm will disable for
approximately 8 seconds. Use this time to disconnect
the wrist cord from the wristband, and attach it to the
park snap or remove the banana plug from the jack.
Upon returning to the workstation and disconnecting
the wrist cord from the park snap, the operator has
approximately 8 seconds to reconnect the wrist cord
to a worn wristband before activating the alarm. The 8
second timer is indicated by the growing intensity of the
park switch's blue LED. The blue LED will pulse when
the operator jack is vacant to indicate standby mode.
G. Power Inlet: Connect the included power cord here.
H. Mat Monitor Screw Terminal: Verifies that the
worksurface's path-to-ground is less than 10 megohms.
Connect the white mat monitor cord here.
I. Set Switch: Toggles the monitor's settings for the
audible alarm and mat monitor circuit.
Function
Procedure
Audible Alarm
Volume
1. Push and release the switch to
toggle the buzzer's volume.
2. The volume will toggle from low,
medium, and high settings.
Enable / Disable 1. Push and hold the switch until
Mat Monitor
all LEDs illmuniate orange.
Circuit
2. Release the switch.
3. An illuminated MAT LED
indicates that the mat
monitor circuit is enabled. A
non-illuminated MAT LED
indicates that the mat monitor
circuit is disabled.
J. Relay Terminal: Integrates with electronic locks,
lights, buzzers, etc. See the "Relay Terminal" section for
more information.
K. Accessory Jack: Connects to the 19323 Power
Relay accessory.
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-3086 Page 3 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Installation
Power Relay
A
B
C
D
E
Power Cord
Full-Time
Continuous Monitor
Mat Monitor Cord
F
G
Grounded
Worksurface Mat
Countersunk Washer
H
Flat Head Screw
Figure 7. Installing the Full-Time Continuous Monitor
Figure 6. Power Relay features and components
A. Normally On Receptacle: Provides power unless
the operator is connected to the Full-Time Continuous
Monitor, and it reports all PASS conditions.
B. Always On Receptacle: Always provides power
regardless of the Full-Time Continuous Monitor's status.
C. Switch Active LED: Illuminates green when the
internal relay switch is activated.
D. Interface Connector: Use the included interface
cable to connect the Full-Time Continuous Monitor to
this connector.
E. Normally Off Receptacles: Provides power when
the operator is connected to the Full-Time Continuous
Monitor, and it does not report any alarm conditions.
F. Power Switch: Rock to RESET to turn on the Power
Relay. Rock to OFF to turn off the Power Relay.
G. Power LED: Illuminates red when the Power Relay
is powered.
1. Remove the Full-Time Continuous Monitor from the
carton, and inspect for damage.
2. Determine the mounting location of the Full-Time
Continuous Monitor. Its LEDs should be visible
to the operator. Secure the Full-Time Continuous
Monitor to a surface using its mounting tabs and the
included pan head screws or dual lock fasteners.
3. Secure the ring termination of the white mat monitor
cord to the mat monitor screw terminal on the back
of the Full-Time Continuous Monitor.
4. Connect the mat monitor cord from the back of
the Full-Time Continuous Monitor to a grounded
worksurface mat. Use the included countersunk
washer and flat head screw to secure the cord to
the grounded mat.
5. Connect the power cord to the power inlet located
on the back of the Full-Time Continuous Monitor.
Connect the opposite end to an appropriate AC
outlet.
H. Power Inlet: Connect the included power cord here.
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-3086 Page 4 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Power Relay
Full-Time
Continuous Monitor
External
Electronic Device
Interface
Cable
Figure 8. Desco 19323 Power Relay
Figure 9. Installing the Power Relay
Pair the 19321 Full-Time Continuous Monitor with the
Power Relay to control power to workbenches, hand
tools, and other electronic devices dependent on the
monitor's status.
1. Determine the mounting location of the Power
Relay. Locate it within reach of its included power
cord. The Power Relay's mounting tabs may be to
secure it onto a surface.
2. Connect the included power cord to the power inlet
located on the side of the Power Relay. Connect the
opposite end to an appropriate AC outlet.
NOTE: The Power Relay is only rated to accept
90-120 VAC input voltage.
3. Connect the included interface cable to the back
of the Full-Time Continuous Monitor. Connect the
opposite end to the green connector on the side of
the Power Relay.
4. Connect the power cord from the Full-Time Monitor
to the Always ON receptacle on the Power Relay.
Figure 10. Using the Power Relay
5. Connect the power cord of the external electronic
device to one of the Normally OFF receptacles on
the Power Relay.
6. Toggle the power switch to the RESET position.
Both the Full-Time Continuous Monitor and the
Power Relay will power on.
7. This setup will power the external electronic device
whenever an operator connects to the Full-Time
Continuous Monitor and no alarms are reported.
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-3086 Page 5 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Relay Terminal
The Full-Time Continuous Monitor features a relay
terminal that can be integrated with electronic locks,
lights, buzzers, etc. The relay will activate when a failure
is reported by the Full-Time Continuous Monitor.
Contact Form
2 Form C
Maximum Switching Power
60 W, 125 VAC
Maximum Switching Voltage 220 VDC, 250 VAC
Maximum Switching Current 2 A
Maximum Carrying Current
2A
Operation
1. Fit the wristband snugly onto the wrist.
2. Snap the wrist cord to the wristband.
3. Plug the wrist cord into the operator jack. The green
operator LED will illuminate. This indicates that the
operator is properly grounded.
4. If this does not happen, examine the wrist cord for
continuity or damage and the wristband to ensure
that it fits securely. If you have dry skin, apply an
approved dissipative hand lotion such as Menda
Reztore® ESD Hand Lotion.
5. When leaving the workstation, first touch the
monitor's park switch or park snap. The monitor's
audible alarm will disable for approximately 8
seconds. Use this time to disconnect the wrist cord
from the wristband and attach it to the park snap
without sounding a false alarm.
NC
C
NO
Figure 11. Relay terminal contacts
10 mm Snap Adapters
6. Upon returning to the workstation and disconnecting
the wrist cord from the park snap, the monitor will
provide approximately 8 seconds for the operator to
reconnect the wrist cord to a worn wristband before
sounding the monitor's alarm.
The 19322 Full-Time Continuous Monitor includes an
interchangeable 10 mm park snap and 10 mm banana
jack adapter for operators who use wrist cords with
10 mm terminations. Use the park snap's knurled rim
to unscrew the 4 mm park snap from the monitor and
install the 10 mm park snap to the monitor. Plug the 10
mm operator jack adapter into the monitor's operator
jack.
Figure 12. Installing the 10 mm snap adapters to the
19322 Full-Time Continuous Monitor
Figure 13. Using the Full-Time Continuous Monitor when
mounted underneath a workbench tabletop
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-3086 Page 6 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Calibration
Frequency of recalibration should be based on the
critical nature of those ESD sensitive items handled
and the risk of failure for the ESD protective equipment
and materials. In general, Desco recommends that
calibration be performed annually.
Use the Desco 98221 Wave Distortion Monitor
Verification Tester to perform periodic verification
(once every 6-12 months) of the Full-Time Continuous
Monitor. The verification tester can be used to check the
test limits of the Full-Time Continuous Monitor without
removing it from the workstation.
See TB-3074 for more information.
Figure 14. Using the Full-Time Continuous Monitor when
mounted on a workbench upright
Figure 16. Desco 98221 Wave Distortion Monitor
Verification Tester
Figure 15. Using the Full-Time Continuous Monitor at a
machine station
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-3086 Page 7 of 8
© 2021 DESCO INDUSTRIES INC
Employee Owned
Specifications
Full-Time Continuous Monitor
Input Voltage and
Frequency
Power Input:
100-240 VAC, 50/60 Hz
Power Cord Length:
6 ft. (1.8 m)
Operating Temperature 50 to 95° F (10 to 35° C)
Environmental
Requirements
Indoor use only at altitudes
less than 6500 ft. (2 km)
Maximum relative humidity
of 80% up to 85° F (30° C)
decreasing linearly to 50% @
85° F (30° C)
Dimensions
2.85" L x 5.13" W x 1.00" H
(72 mm x 130 mm x 25 mm)
Weight
0.35 lbs. (0.16 kg)
Operator Test Range*
500 kilohms to 10 megohms
impedance
Worksurface Test
Limit**
10 megohms (±20%)
Operator Test Voltage
1.2 V peak-to-peak @ 1.2 µA,
open circuit
Worksurface Test
Voltage
Figure 17. Mounting hole locations on the Full-Time
Continuous Monitor (all dimensions are in inches)
Power Relay
Input Voltage and
Frequency
90-120 VAC, 50/60 Hz
Output Voltage
90-140 VAC
5 to 7.5 V, open circuit
Max Load
12 A
Alarm Response Time