TB-9029
Page 1 of 6
© 2015 DESCO NDUSTRIES, NC.
Employee Owned
Wrist Strap and Ground Monitor
Installation, Operation and Maintenance
October 2015
USER GUIDE TB-9029
Description
The SCS 773 Wrist Strap and Ground Monitor can
be used in work areas or other locations to monitor
the ground impedance of metal ground connection in
process tools including but not limited to semiconductor,
disk drive, flat panel and electronic equipment
manufacturing environments. Ground impedance
monitoring can be used for up to two points for metal
ground, such as within a tool. The Wrist Strap and
Ground Monitor can be used to monitor the impedance-
to-ground and voltage level on two persons wearing
dual-wire wrist straps. The unit incorporates green and
red LEDs and an audible alarm, as well as an output
logic signal to a host equipment.
Ground Impedance Monitor
– Continuously monitors
for ground impedance on one or two separate channels
that are connected to one or two process tools. The
alarm level is set the same for all channels.
Output Signal
– An output signal is available for
connecting to the tool’s computer or PLC. The 5V signal
is either logic 1 or 0 for indicating the monitored ground
resistance/impedance conditions and for the wrist strap.
Operator Connection
– The Wrist Strap and Ground
Monitor provides continuous monitoring of operator
connection to the monitor via loop resistance check of
operator’s physical presence using a dual wire wrist
strap.
Voltage on Person Wrist Strap Monitor
– The Wrist
Strap and Ground Monitor has one additional feature
that allows continuous monitoring for excessive voltage
on each operator.
The Wrist Strap and Ground Monitor is available in one
model:
Item
Description
773
Wrist Strap and Ground Monitor, with World
Wide Power Adapter
SCS offers the following accessories for the Wrist Strap
and Ground Monitor:
Item
Description
2368
Dual Conductor Fabric Adjustable
Wristband
2360
Dual Conductor Coil Cord, 5'
2370
Dual Conductor Coil Cord, 10'
CTA252
Replacement Jack PCB, 773 Wrist
Strap and Ground Monitor
CTE701
Workstation Monitor Checker
CTA212
Power Adapter, 100-240VAC Input,
12VDC 1.5A Output, All Plugs
Packaging
1 Wrist Strap and Ground Monitor
1 Monitor Ground Cord (Green and Yellow)
1 Power Adapter, 12VDC, with interchangeable plugs
(North America, UK/Asia, Europe)
1
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Installation
Wire Attachment
Attach 18 AWG wires to the unit as described below.
Strip back the vinyl insulation at each end of the wires
to approximately 1/3 inch (8 mm). Twist the stranded
wire on each end before inserting the wire into each
connector location. In order to attach the wire, insert
a small blade screwdriver into the orange slot above.
Gently push inward and insert the stripped wire fully into
the hole in the green connector. Hold the wire fully in
and release the screwdriver to allow the wire to catch.
Attach the ground wire to the “GND” connector on back
of unit. Attach the impedance monitor wire(s) to the
chosen ground lines “G1, G2” connector(s) on the back
of the unit.
If you are planning to use the SCS Wrist Strap and
Ground Monitor output to the tool, attach the wire to the
“Out” connector on the back of the unit.
Made in the
United States of America
Figure 1. SCS
773
Wrist Strap and Ground Monitor
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176