Unit 17. Millbrook Business Park, Sybron Way • Crowborough, East Sussex TN6 3JZ United Kingdom
Phone: 00 44 (0) 1892-665313 • Internet:
PPE-5098.E
Page 2 of 4
© 2014 Charleswater
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 (1.5 meter tall 41 kilogram person to 1.8 meter 13
centimeter 91 kilogram person), the Jewel
®
Workstation
Continuous Mini Monitor 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 standards. The Jewel
®
Workstation
Continuous Mini 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
The Jewel
®
Workstation Continuous Mini 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 and less durable dual-wire cords and
special wrist straps. The Jewel
®
Workstation 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
The Jewel
®
Workstation Continuous Mini Monitor
monitoring circuitry is sufficiently sensitive to detect
extremely low current, allowing it to be used with mats
having a resistance of up to 5 x 10
8
ohms RTG. When
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
1 Jewel
®
Workstation Continuous
Mini Monitor
2 Push and Clinch Snaps
1 Power Adaptor, 24 VAC
1 Banana Plug / 10mm Snap Adapter
1 Certificate of Calibration
Cords must be ordered separately.
Installation
Confirm that the surface resistance (Rtg) of the mat is
5 x 10
8
ohms or less and has a conductive layer. We
recommend the Charleswater
99105
or
99111
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
Figure 2. Installation of push and clinch snaps to
worksurface.
