Desco 19234, 19228, 19229, 19258, 19236 Technical Bulletin

TECHNICAL BULLETIN TB-3054

Multi-Mount Continuous Monitor
Installation, Operation and Maintenance

The Multi-Mount Monitor and its accessories are
available as the following item numbers:

Item Description

19228 Multi-Mount Monitor, North America

19229 Multi-Mount Monitor, with Jewel® Wrist Strap,

North America

19234 Multi-Mount Monitor, Universal Power Adapter

19236 Multi-Mount Monitor, with Jewel® Wrist Strap,

Universal Power Adapter

19258 Power Adapter, 100-240VAC Input, 24VDC

150mA Output, IEC Inlet

19260 Power Adapter, 100-240VAC Input, 24VDC

150mA Output, North America Plug

Figure 1. Desco Multi-Mount 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 Multi-Mount
Continuous Monitor continuously monitors the integrity
of one operator. This monitor will provide virtually
instantaneous notification of static control equipment
failures, eliminating the need of periodic testing and
costly record keeping. This unit is highly cost effective
as it is designed to monitor any conventional single wire
wrist strap and ground cord system. Its small package
and mounting tabs with holes make it highly suitable to
install on most any equipment or work bench surface.
In addition, optional mounting is available using the
provided adhesive-backed Velcro® strips. Using either
mounting method makes the Multi-Mount Monitor
suitable for most any machinery or workbench even in
hard to reach locations.

The Multi-Mount Continuous Monitor is a real time
instrument that ensures that critical ESD generators in a
sensitive area are effectively grounded. The instant an
operator’s wrist strap or cord fails, the monitor will issue
audible and visual (LEDs) alarms alerting the user and
supervisor of the problem.

All Desco single-wire monitors with wave distortion
technology include the Park Snap feature. Use the
Park Snap to store the operator’s wrist cord and enable
standby mode while the operator is away from the
workstation. Before disconnecting the coil cord from
the wristband, the operator touches the Park Snap to
disable the audio alarm for 6 seconds. Within the 6
second period, the operator can disconnect their wrist
cord from their wristband and attach it to the Park Snap
before the audible alarm sounds.

98220 Calibration Unit, for Wave Distortion Monitors

WAVE DISTORTION DETECTION TECHNOLOGY
PROVIDES TRUE 100% CONTINUOUS
MONITORING

From all the technical alternatives available, Desco
has chosen wave distortion technology for many of 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 Multi-Mount Continuous Monitor will
reliably determine if the circuit is complete.

Wave distortion technology can be referred to “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.

In normal factory environments, and with persons
whose capacitance with respect to ground is within
design limits (5 feet tall 90 pound person to 6 foot 5
inch 250 pound person), the Multi-Mount Continuous
Monitor cannot be “fooled”. It will provide a reliable
alarm only when the wrist strap becomes dysfunctional
or unsafe according to accepted industry standards.
The Multi-Mount Continuous Monitor is drift-free and
designed to be insensitive to the effects of squeezing or
stretching the coil cord.

Made in the

United States of America

TB-3054 Page 1 of 6

May 2017

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

ADVANTAGES OF WAVE DISTORTION AND
SINGLE-WIRE TECHNOLOGY

The Desco Multi-Mount Continuous Monitor allows the
use of any standard, single-wire wrist strap and coil
cord. The monitor/wrist strap/cord system life-cycle
costs are by far lower than alternative systems which
require expensive & fragile dual-wire cords and special
wrist straps. Dual-wire cords are expensive and are
the weak link of the system, the most likely component
to need replacement. Over a five year period, this
can make the dual-wire system three to five times as
expensive as a system utilizing single-wire wrist straps
and cords. See Maintenance and Calibration (page 4)
to minimize life-cycle costs.

The dictionary defines constant as uniform and
unchanging, and continuous as uninterrupted.
None theless, some dual-wire resistance monitors
utilize a pulsed test current and do not really provide
continuous monitoring. For example, during each 2.2
second pulse cycle of a leading “constant” resistive
monitor, electrical current is pulsed for only 0.2 seconds
followed by an unmonitored interval of 2 seconds.
This leaves the user/wrist strap unmonitored for over
90% of each cycle. Damaging static charges can
easily occur in the portion of the time in between
the pulses. The off period of 2 seconds equals 2
billion nanoseconds, and “it takes only about 25 volts
applied for 100 nanoseconds to blow most memories
or microprocessors.* The dual-wire system does not
reliably meet all industry specifications, as the cords
do not meet the EOS/ESD S-1.0 paragraph 4.1.6, 1 to
5 pound “breakaway force” requirement for operator
safety.

By using the reliable wave distortion technology to
determine if the circuit is complete, there are no false
alarms. There is no need to adjust or tune the monitor
to a specific user or installation. The miniscule amount
of electrical current (less than 1 volt coil cord signal)
required to generate the waveform has never caused
reported skin irritation and is extremely safe for use
in voltage sensitive applications such as disk drive
manufacturing.

WORKSURFACE CHANNEL

The Multi-Mount Continuous Monitor’s circuitry is

su󰀩ciently sensitive to detect extremely low current,

allowing it to be used with mats having a resistance
of up to 1.0 x 107 ohms Rtg. When the Monitor is
connected to an ESD Mat worksurface, the amount of

current that ows is a function of the total resistance

between the monitor and through the worksurface to
ground. When the resistance of the worksurface is
below a pre-set threshold, the monitor will indicate
good. Conversely, if the resistance level is high when
compared to the monitor’s reference, the unit will alarm.
This is an integrating resistance measuring circuit,
therefore it is relatively insensitive to externally induced

electromagnetic elds. The resistance threshold is

factory set to 10 megohms. (It can be special ordered
to other limits. Limits can be varied and set to 100
megohms maximum).

Packaging

19228 Multi-Mount Continuous Monitor, 120VAC

1 Multi-Mount Continuous Monitor
1 24VDC Power Adapter, North America Plug
1 6' Mat Monitor Cord (Black)
1 6' Mat Ground Cord (Green and Yellow)
2 Push and Clinch Snaps
2 Mounting Screws
2 Countersink Washers
1 Set of Hook and Loop Fasteners
1 Zip Tie
1 Certificate of Calibration

19229 Multi-Mount Continuous Monitor, 120VAC

1 Multi-Mount Continuous Monitor
1 24VDC Power Adapter, North America Plug
1 09100 Jewel® Elastic Wristband
1 6' Mat Monitor Cord (Black)
1 6' Mat Ground Cord (Green and Yellow)
2 Push and Clinch Snaps
2 Mounting Screws
2 Countersink Washers
1 Set of Hook and Loop Fasteners
1 Zip Tie
1 Certificate of Calibration

*1981 article by Donald E. Frank - Electrical Overstress /
Electronic Discharge Symposium Proceedings

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

TB-3054 Page 2 of 6

19234 Multi-Mount Continuous Monitor, 220VAC

1 Multi-Mount Continuous Monitor
1 24VDC Power Adapter without Power Cord
1 6' Mat Monitor Cord (Black)
1 6' Mat Ground Cord (Green and Yellow)
2 Push and Clinch Snaps
2 Mounting Screws
2 Countersink Washers
1 Set of Hook and Loop Fasteners
1 Zip Tie
1 Certificate of Calibration

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

19236 Multi-Mount Continuous Monitor, 220VAC

1 Multi-Mount Continuous Monitor
1 24VDC Power Adapter without Power Cord
1 09100 Jewel® Elastic Wristband
1 6' Mat Monitor Cord (Black)
1 6' Mat Ground Cord (Green and Yellow)
2 Push and Clinch Snaps
2 Mounting Screws
2 Countersink Washers
1 Set of Hook and Loop Fasteners
1 Zip Tie
1 Certificate of Calibration

Features and Components

A

B

I
H

G

F

NOTE: The power cord must be purchased separately
for Multi-Mount Monitor items 19234 and 19236. See
the following EMIT items for available power cords:

Item Power Cord Type

50545 Europe

50546 United Kingdom

Figure 2. 220VAC power adapter included with the
Desco 19234 and 19236 Multi-Mount Continuous
Monintors. Power cord sold separately.

C D E

Figure 3. Multi-Mount Continuous Monitor features and
components

A. Status LEDs: When the green LED is illuminated,
the operator is properly grounded. When the red LED is
illuminated, the operator is not properly grounded.

B. Monitored Operator Jack: Where the operator
inserts the wrist cord banana plug.

C. Worksurface Ground LEDs: When the green LED
is illuminated, the worksurface mat is properly grounded.
When the red LED is illuminated, the worksurface mat is
not properly grounded.

D. Operator Ground LEDs: When the green LED is
illuminated, the operator is properly grounded. When
the red LED is illuminated, the operator is not properly
grounded.

E. 4mm Parking Snap: When touched by the operator,
this snap will deactivate the alarm for six seconds. This
allows time for the operator to disconnect the coil cord
from the wrist band and park it on this snap. While
parked, the coil cord disables the alarm, allowing the
operator to leave the workstation. The OPERATOR
GROUND LED will remain off while the cord is parked.
Upon returning and removing the coil cord from the
parking snap, the operator has six seconds to hook up
to the wrist band before the alarm sounds.

TB-3054 Page 3 of 6

F. Cable Tie Mount: Pair with the included zip tie to

secure the nearby power adapter cord and reduce strain
on its plug.

G. Power Jack: Connect the power adapter here.

H. Mat Connection: Monitors worksurface mat.

NOTE: To disable worksurface monitoring, shunt this
terminal to the neighboring GND terminal with bus wire.

I. Mat Ground: Grounds worksurface mat.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

Installation

Worksurface

Figure 4. Installation method #1

Snaps must be 12 to 72 inches apart

Figure 6. Screw allows ground cord to be bolted to mat
to keep cord from disconnecting

5. The ground cord included with the Multi-Mount
Continuous Monitor may be used to ground the
worksurface mat if it is not already grounded.
Attach the tinned wire end of the included ground
cord to the appropriate terminal block connection on
the right-side of the monitor.

6. Route the ground cord from the monitor to the
worksurface mat. Use either the included push and
clinch snap or washer and screw to secure the cord
to the mat. This snap must be installed 12 to 72
inches away from the snap used for the mat monitor
cord.

7. Connect the power adapter to the power jack
located on the right-side of the monitor. Route the
wire from the supply to a nearby AC outlet and
plug it into the outlet. Make sure the voltage and
frequency match those listed on the power supply.
The monitor is now powered.

Worksurface

Figure 5. Installation method #2

1. Remove the monitor from the carton and inspect for
damage.

2. Determine the mounting location of the Multi-Mount
Continuous Monitor. Its LEDs should be visible to
the operator. Use the included mounting screws or
hook and loop fasteners if desired.

3. Attach the tinned wire end of the mat monitor cord
to its appropriate terminal block connection located
on the right-side of the monitor.

4. Route the mat monitor cord from the monitor to the
worksurface mat. Use either the included push and
clinch snap or washer and screw to secure the cord
to the mat (see Figure 6).

NOTE: Worksurface must have a conductive layer
such as Dual Layer Rubber or Dissipative 3-Layer
Vinyl or Micastat® Dissipative Laminate with conductive
buried layers. Desco continuous monitors are not
recommended for use with homogeneous matting.

2.08

.188

3.50

.90

3.87

TB-3054 Page 4 of 6

Figure 7. Mounting hole locations on the Multi-Mount
Continuous Monitor (all dimensions are in inches)

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

Operation

When the Multi-Mount Continuous Monitor is installed
to an ESD protective worksurface and grounded via
a power cord, the green WORKSURFACE GROUND
LED and red OPERATOR GROUND LED should be
illuminated. The monitor takes 6 seconds to activate its
alarm circuitry when the operator is first plugged in.

The custom AC adapter connects the outlet ground to
the barrel on the output plug. This is used to supply the
Monitor with ground.

The worksurface resistance is measured between the
two cords installed to the mat worksurface.

USING THE MONITOR

1. Plug a wrist cord into the operator jack on the left­side of the monitor. This automatically activates the
selected operator channel. The red operator LED
should turn on.

2. Remove the charges from your body by making
contact with a properly grounded ESD worksurface.

Snap the cord to the wristband, and t it snugly

onto the wrist. This should silence the audio and
cause the LEDs to switch from red to green. If this
does not happen, check the coil cord for continuity

or damage. Examine the wrist strap and conrm
that it has a secure t. If you have dry skin, apply

an approved dissipative hand lotion such as Menda

35659 Reztore™ ESD Hand Lotion. When leaving

the area, a person can take the coil cord along or
leave it attached to the monitor in park position.

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 98220 Calibration Unit for Wave
Distortion Monitors to perform periodic verification
(once every 6-12 months) of the Mini Monitor. The
Calibration Unit can be used to check the test limits of
the Multi-Mount Monitor without removing it from the
workstation.

See TB-2082 for more information.

NOTE: Removing the banana plug from the monitor’s
operator jack will disable the audio alarm.

It is recommended that you use the Park Snap rather
than continuously removing the banana plug from its
jack. Doing so will increase the life span of the operator
jack. If your process requires the constant insertion and
removal of the banana plug, please contact your Desco
Representative for alternate solutions.

Figure 8. Using the Multi-Mount Continuous Monitor

Figure 9. Desco 98220 Calibration Unit for Wave
Distortion Monitors

TB-3054 Page 5 of 6

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

Specifications

Input Voltage and
Frequency
(External Adapter)

Operating Temperature 50 to 95°F (10 to 35°C)

Environmental
Requirements

Dimensions 3.87" L x 2.08" W x .90" H

Weight 0.1 lbs. (0.05 kg)

Operator Test Range* 500 kilohms to 10 megohms

Worksurface Test
Limit**

Operator Test Voltage 1.2V peak-to-peak @ 1.2µA,

Worksurface Test
Voltage

Alarm Response Time <50 ms

Country of Origin United States of America

AC/DC Power Adapter

Power Input:
100-240VAC, 50/60 Hz

Power Output:
24VDC @ 150mA

Cable Length:
5 ft. (1.5 m)

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)

(98 mm x 53 mm x 23 mm)

impedance

10 megohms (±10%)

open circuit

5 to 7.5V, open circuit

Limited Warranty, Warranty Exclusions, Limit
of Liability and RMA Request Instructions

See the Desco Warranty -

http://desco.descoindustries.com/Limited-Warranty.aspx

*This cannot be verified with standard DC test
equipment. The continuous monitor is an impedance
sensing device, and the limits are determined by the
magnitude and angle of the impedance.

**The worksurface mat must have a conductive
layer such as Dual Layer Rubber or Dissipative
3-Layer Vinyl with conductive buried layers. Desco
workstation monitors are not recommended for use with
homogeneous matting.

TB-3054 Page 6 of 6

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

© 2017 DESCO INDUSTRIES, INC.

Employee Owned

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

Desco:
19228