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-3050 Page 2 of 4

© 2013 DESCO INDUSTRIES, INC.

Employee Owned

Wave distortion technology can be referred to as “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

cannot be “fooled”. It will provide a reliable alarm only

when the wrist strap or work surface becomes

dysfunctional or unsafe according to accepted industry

Monitor is drift-free and designed to be insensitive to the

effects of squeezing or stretching the coil cord.

Advantages Of Wave Distortion And Single-

Wire Technology

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 and less durable dual-wire

Continuous Mini Monitor is an economical way to

monitor both the operator’s wrist strap and workstation

surface. See “Maintenance and Calibration” (page 4) to

minimize life-cycle costs.

The dictionary defines constant as uniform and

unchanging, and continuous as uninterrupted.

Nonetheless, some dual-wire resistance monitors utilize

a pulsed test current and do not 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”.*

By using the reliable wave distortion impedance

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

monitoring circuitry is sufficiently sensitive to detect

extremely low current, allowing it to be used with mats

the Monitor is connected to an ESD Mat worksurface,

the amount of current that flows 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 fields. The resistance threshold

is factory set to 500 megohms. (It can be special

ordered to other limits. Limits can be varied and set to 1

gigohm maximum.)

Packaging

2 Push and Clinch Snaps

1 Power Adapter, 24VAC, N. America

1 Certificate of Calibration

Installation

Confirm that the surface resistance (RTG) of the mat is

recommend the Desco 19787 or 19784 Meter. Remove

the monitor from its packaging and inspect for any

shipping damage.

The Continuous Mini Monitor is normally installed toward

the front edge of a workstation where the LEDs are

easily visible. The unit is designed to be snapped on the

worksurface using the 10mm snap studs mounted at the

bottom of the monitor (see Figure 2).

ESD MAT

Push and Clinch Snaps

1-5/16"

Figure 2. Installation of push and clinch snaps to

worksurface