Desco 19258, 19243, 19242, Mini Monitor 19239, 19260 Installation, Operation And Maintenance Manual

TECHNICAL BULLETIN TB-3072

Mini Monitor
Installation, Operation and Maintenance

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 sine wave that the monitor circuit compares
to established patterns. By monitoring the “distortions”,
or shape of the sine 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 (<50
milliseconds) 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

Figure 1. Desco Mini Monitor

Description

The Desco Mini Monitor is a single workstation
continuous monitor. It continuously monitors the
path-to-ground integrity of one operator and one ESD
worksurface. The Mini Monitor eliminates the need for
periodic testing and record keeping of wrist straps.

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.”

Made in the

United States of America

The Mini Monitor is designed with Wave Distortion
Technology which provides 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 50 milliseconds) when the
operator unintentionally disconnects from the monitor or
the wrist strap connection points are intermittent. The
Mini Monitor also serves as a ground point for an ESD
worksurface and monitors for a path-to-ground of less
than 500 megohms. All Mini Monitors are calibrated to
NIST standards and include a certificate.

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

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

The Mini Monitor and its accessories are available as
the following item numbers:

Item Description

19239 Mini Monitor, Black, North American Power

Adapter

19242 Mini Monitor, Blue, with Jewel® Wrist Strap,

North American Power Adapter

19243 Mini Monitor, Black, 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

98221 Wave Distortion Monitor Verification Tester

TB-3072 Page 1 of 6

July 2018

© 2018 DESCO INDUSTRIES INC

Employee Owned

Packaging

19239 Mini Monitor, North America

1 Mini Monitor
2 Countersunk Washers
2 Flat Head Screw, 6-32 x 1/4"
1 Power Adapter, 24VDC, North America Plug
1 Certificate of Calibration

19242 Mini Monitor, Jewel® Kit, North America

1 Mini Monitor
1 09100 Jewel® Elastic Wrist Strap
2 Countersunk Washers
2 Flat Head Screw, 6-32 x 1/4"
1 Power Adapter, 24VDC, North America Plug
1 Certificate of Calibration

19243 Mini Monitor, Universal Power Adapter

1 Mini Monitor
2 Countersunk Washers
2 Flat Head Screw, 6-32 x 1/4"
1 10mm Interchangeable Park Snap
1 10mm Operator Jack Adapter
1 Power Adapter, 24VDC, IEC Inlet
1 Certificate of Calibration

Figure 3. Universal power adapter included with the

19243 Mini Monitor

NOTE: The power cord must be purchased separately
if ordering the 19243 Mini Monitor. The power cords are
available as the following item numbers:

Figure 2. North American power adapter included with
the 19239 and 19242 Mini Monitors

Item Plug Type

50545 Europe

50546 United Kingdom

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

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

TB-3072 Page 2 of 6

© 2018 DESCO INDUSTRIES INC

Employee Owned

Features and Components

D

A. Power Jack: Connect the included 24VDC power

adapter here.

B. Operator LEDs: Illuminates green when the
operator is properly grounded. Illuminates solid red and
audible alarm sounds when the operator is not properly

A

grounded.

C. Worksurface LEDs: Illuminates green when the
worksurface is properly grounded. Illuminates red and
audible alarm sounds when the worksurface is not
properly grounded.

D. 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 and the
monitor's audible alarm will disable for approximately 10

B

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 10 seconds
to reconnect the wrist cord to a worn wristband before
activating the alarm.

C

E. Monitored Operator Jack: Insert the single-wire

wrist cord here to monitor the operator's connection to
ground.

F. Threaded 10mm Ground Snap: Connects the
worksurface mat to electrical ground.

G. Threaded 10mm Worksurface Monitor Snap:
Verifies that the worksurface's path-to-ground is <500
megohms.

E

F

G

Figure 4. Mini Monitor features and components

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

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

TB-3072 Page 3 of 6

© 2018 DESCO INDUSTRIES INC

Employee Owned

Installation

1. Remove the Mini Monitor from the carton, and
inspect for damage.

2. Locate an appropriate AC outlet near the Mini
Monitor, and test it for proper wiring and grounding
prior to use. The Desco AC Outlet Analyzer or
similar test equipment may be used to verify the
outlet’s functionality. Use item number 98132 for
120VAC North American outlets and item number

98131 for 220VAC UK outlets.

3. Determine the mounting location of the Mini Monitor.
It is normally installed toward the front edge of a
workstation where its LEDs can be visible to the
operator. Use a blade to pierce two holes 1-5/16"
apart from one another into the worksurface mat.

4. Use a Phillips screwdriver to secure the two flathead
screws and countersunk washers through the
worksurface mat and into the two threaded 10mm
snaps on the bottom of the Mini Monitor.

Installation onto Micastat® Laminate

Materials Needed:
2 14244 Micastat® Flush Mount Ground Inserts
1 14242 Micastat® Flush Mount Insert Tool
1 09857 10mm Socket and Rivet (100 per pack)
2 8-32 Button Cap Screws

1. Install the two flush mount ground inserts into the
Micastat® laminate. Space the inserts 1-5/16" apart
from one another.

2. Once the ground inserts are installed, remove the
8-32 screws that were supplied with the kits.

3. Place 10mm snap sockets on top of the installed
brass ground inserts.

4. Screw the 10mm snap sockets into place on the
ground inserts using the 8-32 button cap screws.

5. Align the two snaps underneath the Mini Monitor
to the two snaps on the Micastat® laminate. Apply
downward force on the monitor once aligned to
snap the Mini Monitor into place.

6. Connect the power adapter to the power jack
located on the top-side of the Mini 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 Mini Monitor is now powered, and the
Micastat® laminate is now grounded.

Figure 5. Securing the Mini Monitor to a worksurface mat

5. Connect the power adapter to the power jack
located on the top-side of the Mini Monitor. Connect
the wire from the supply to the tested AC outlet, and
plug it into the outlet.

NOTE: Older revision Mini Monitors do not feature
threaded 10mm snaps on their bottom-side. They
require the use of push and clinch snaps to secure the
monitor to the worksurface mat.

10mm Park Snap and 10mm Operator Jack Adapter

The 19243 Mini Monitor includes an interchangeable
10mm park snap and 10mm banana jack adapter for
operators who use wrist cords with 10mm terminations.
Use the park snaps' knurled rims to unscrew the 4mm
park snap from the monitor and install the 10mm park
snap to the monitor. Plug the 10mm operator jack
adapter into the monitor's operator jack.

Figure 7. Changing the park snap on the 19243 Mini
Monitor

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

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

TB-3072 Page 4 of 6

© 2018 DESCO INDUSTRIES INC

Employee Owned

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 snap. The monitor's audible alarm
will disable for approximately 10 seconds. Use this
time to disconnect the wrist cord from the wristband
and attach it to the park snap without sounding a
false alarm.

6. Upon returning to the workstation and disconnecting
the wrist cord from the park snap, the monitor will
provide approximately 10 seconds for the operator
to reconnect the wrist cord to a worn wristband
before sounding the monitor's alarm.

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 Mini Monitor. The verification
tester can be used to check the test limits of the Mini
Monitor without removing it from the workstation.

See TB-3074 for more information.

Figure 8. Using the Mini Monitor

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

Figure 9. Desco 98221 Wave Distortion Monitor

Verication Tester

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

TB-3072 Page 5 of 6

© 2018 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 2.77" 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)

(70 mm x 53 mm x 23 mm)

impedance

500 megohms (±20%)

open circuit

5 to 7.5V, open circuit

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

See the Desco Warranty -

Desco.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.

ANSI/ESD S20.20 requires the use of a surface
resistance meter for periodic verification of a
worksurface's resistance-to-ground (Rtg). Constant
monitors may not be used as a substitute for this
requirement.

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

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

TB-3072 Page 6 of 6

© 2018 DESCO INDUSTRIES INC

Employee Owned