USER GUIDE TB-9029
Wrist Strap and Ground Monitor
Installation, Operation and Maintenance
Made in the
United States of America
The Wrist Strap and Ground Monitor is available in one
model:
Item
773
Description
Wrist Strap and Ground Monitor, with World
Wide Power Adapter
SCS offers the following accessories for the Wrist Strap
and Ground Monitor:
Item
2368
2360
Figure 1. SCS
773
Wrist Strap and Ground Monitor
2370
CTA252
CTE701
CTA212
Description
Dual Conductor Fabric Adjustable
Wristband
Dual Conductor Coil Cord, 5'
Dual Conductor Coil Cord, 10'
Replacement Jack PCB, 773 Wrist
Strap and Ground Monitor
Workstation Monitor Checker
Power Adapter, 100-240VAC Input,
12VDC 1.5A Output, All Plugs
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.
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 Certificate of Calibration
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.
SCS
- 926 JR Industrial Drive, Sanford, NC 27332 • (919) 718-0000 • Website:
StaticControl.com
TB-9029
Page 1 of 6
October 2015
© 2015 DESCO INDUSTRIES, INC.
Employee Owned
Figure 2. Rear view of Wrist Strap and Ground Monitor
AC/DC Adapter Connection
Connect the circular plug of the power adapter into the
power jack on the back of the unit.
Mounting
Determine the mounting location of the Wrist Strap
and Ground Monitor. Attach the unit using one of the
following recommended methods:
•
•
Screws
Dual Lock Reclosable Fastener
Person Voltage and Resistance Monitor
The alarm level is monitored when a person is wearing
a dual conductor wrist strap assembly and plugged into
the front jack. There is a short hold on the body voltage
alarm so that it is not missed. The unit will respond
to either a positive or negative voltage. The alarm is
activated when the wrist strap is worn too loosely and
the loop resistance level is exceeded. The red LED
indicates the resistance limit without a voltage being
generated on the person at the same time. The green
LED indicates a proper connection of the operator. A
green LED plus a blinking red LED will indicate if there
is a body voltage generated; the operator may still be
connected properly. The green LED is off when a dual
conductor ground cord is not plugged into the jack.
Enabling and Disabling Audible Alarm
The audible alarm can be enabled or disabled by
momentarily pressing a recessed miniature push-button
“Set” switch located on the back of the unit while the
monitor’s power is on. Use a paper clip to press the
switch. One short beep on power up means that the
sound is disabled. A series of two short beeps means
that the sound is enabled.
Enabling or Disabling Monitoring of Ground Lines
In some instances, both of the two ground points in the
tool do not need to be monitored. This procedure will set
up the number of ground lines (G1, G2) that will be used,
so that there is no need to put jumpers or shunts on
the unused ground monitoring inputs. The AC Adapter
should not be plugged in at this time.
•
•
•
•
Attach the “GND” line to ground.
Attach the monitor line(s) (G1, G2) to the ground that
has been determined to use. Do not plug any wires
into those ground monitor inputs that will be unused.
Press and hold the “Set” button using the end of a
paper clip. While the button is pressed inward, plug
in the AC Adapter and then release the “Set” button.
Wait then for ~30 seconds. The SCS Wrist Strap
and Ground Monitor will beep during this time. After
this, it will produce one beep and will automatically
disable the lines to which nothing was connected.
You can repeat this procedure whenever a change
in monitoring of the number of ground lines is
required.
Note: The unit can be mounted upside down from the
current orientation of the front and back covers. If you
wish to change the orientation, rotate the printed circuit
board and covers 180 degrees. This will allow the unit
housing to be mounted from the wider plate with screw
slots.
Operation
Ground Impedance Alarm Level
Use the set switch and select through a combination
of LED patterns on the front of the monitor to set the
alarm level. The alarm level can be set to 1-10 ohms in
1 ohm increments. It can also be set to 10-20 ohms in
2 ohm increments. The two monitoring lines are set to
the same selected impedance value. If the measured
impedance on a line is lower than the setting, a green
LED will remain illuminated for that line(s). If the
impedance is higher than the preset level, a red LED
and audible alarm are activated for that line(s). Their
alarm duration will be on momentarily to prevent missing
a short increased resistance event. If the impedance
level remains above the preset alarm level, the red LED
and audible sound remains on.
Note: A wire must be attached from the SCS Wrist Strap
and Ground Monitor (GND terminal) to an approved
ground point to monitor the grounding of process tools
correctly.
Output Signal Level
The output connector provides a logic 1 (+5V) when all
grounds are within the limits and the unit is powered on.
The output connector provides a logic 0 (0V) if any of the
monitored grounds or wrist strap fail or power to the unit
is lost.
Setting Impedance Alarm Levels
By default, the SCS Wrist Strap and Ground Monitor is
set at the factory to 10 ohms alarm level.
If you wish to change the alarm level to your
specifications, follow this procedure to set the
impedance alarm level for all channels (G1, G2).
•
•
•
Repeat the steps above in Enabling or Disabling
Monitoring of Ground Lines section.
Right after the beeping stops, continue pressing the
“Set” button until the impedance level is matched.
When the beeping stops, the left four LEDs allow for
setting of resistance value. G1 & G2 red LEDs are
upper location and G1 & G2 green LEDs are lower.
Select the ground resistance value by repeatedly
SCS
- 926 JR Industrial Drive, Sanford, NC 27332 • (919) 718-0000 • Website:
StaticControl.com
TB-9029
Page 2 of 6
© 2015 DESCO INDUSTRIES, INC.
Employee Owned
•
pressing the “Set” button to advance the resistance
limit. This will turn the LEDs on or off as indicated in
the table on the following page.
Do not press the “Set” switch for about seven
seconds. The new limit will be saved and normal
operation will start.
14
16
Using the LEDs to Set the Resistance Alarm Level
Resistance LED
(Ohms)
1
20
18
2
Calibration
3
Equipment Required
For this test, the SCS Wrist Strap and Ground Wrist
Strap and Ground Monitor should be disconnected from
the monitored grounds.
Use the SCS
CTE701
Workstation Monitor Checker.
Connect the ground input of the checker to the ground
terminal of the Wrist Strap and Ground Monitor. Set
the checker to a proper resistance alarm level (see
the CTE701 User Guide). Connect the red tip of the
checker to the ground monitoring terminal (i.e. G1, or
G2). Press the Fail button on the checker. The red
LED of the corresponding ground of the monitor should
remain on. Press the Pass button on the checker – the
corresponding light on the monitor should be green.
Repeat these steps for all enabled ground monitoring
inputs.
The checker verifies the proper operation of dual wrist
strap monitoring. Connect a 3.5 mm test cable to both
the checker and to the operator jack of the monitor. At
this point the monitor should indicate failure. Depress
the Pass button on the wrist strap section. The monitor
should indicate a good connection. While pressing the
Pass button, press body voltage “high.” At this point the
Wrist Strap LED would be blinking red.
4
5
6
7
8
9
10
12
Figure 3. SCS CTE701 Workstation Monitor Checker
SCS
- 926 JR Industrial Drive, Sanford, NC 27332 • (919) 718-0000 • Website:
StaticControl.com
TB-9029
Page 3 of 6
© 2015 DESCO INDUSTRIES, INC.
Employee Owned
Functional Operation
Ground Resistance Monitor
•
Connect the ground wire to a known good electrical
ground point.
•
Connect the output wire to the tool if you intend to
use it, otherwise leave it open.
•
Connect the ground monitor inputs to the identified
locations. Be sure to connect the monitoring inputs
to different physical locations than those points used
for their grounding.
Person Voltage and Resistance Monitor
Plug the dual conductor ground cord of the wrist strap
into the jack on the front of the unit. If the wrist strap
is worn properly, a green LED will come on; otherwise
red LED will be on. In order to provide good ground
connection, the wrist strap must be worn tightly and the
green light on the SCS Wrist Strap and Ground Monitor
is an indication of that.
If for whatever reason, while properly connected, the
operator developed excessive body voltage (in excess
of ± 2.5 Volts in any polarity), the green LED may still be
on, but the red LED will blink without alarm sound. No
LED is on if a dual conductor ground cord is not plugged
into the jack.
Specifications
Ground Impedance
Alarm Level
Wrist Strap Alarm -
Body Voltage
Wrist Strap Alarm -
Operator Loop
Resistance
Output Signal Level
1 to 20 ohms
±2.5V on operator
10 megohms on operator (plus
two 1 megohm resistors in the
end of the ground cord that
attaches to the wristband)
Logic 1 (+5V) if below selected
resistance level (all “pass”)
Logic 0 (0V) if above selected
resistance level (any failure or
power loss)
Note: This is for both process
tools and wrist strap monitoring.
Visual Alarm
Indicator (LED)
Green: OK
Red: Fault Condition
Note: Operator LEDs red and
green will not illuminate if wrist
strap is not plugged into jack.
Buzzer fault condition if enabled
Temperature: 50 to 110ºF (10 to
43ºC)
Humidity: 75% R.H. maximum
2.42” W x 2.45” L x 0.85” H
(61mm W x 62mm L x 22mm H)
Output: 12VDC @ 1.5A
Output Plug Polarization:
Center Positive
Output Plug: 5.5 mm O.D. x 2.1
mm I.D. x 9.5 mm L
Maintenance
Replacement and Removing Input Wrist Strap Dual
Conductor Input Jack
If the wrist strap input jack begins to show wear after
heavy usage, the input jack can be replaced by ordering
the SCS
CTA252
Replacement Wrist Strap Jacks.
Remove the input jack in the unit by removing the
locking collar and two screws on front cover. Slide the
printed circuit board outside of the unit and unplug the
pin connector with input jack board. Plug in new input
jack board assembly and carefully slide the board back
into the housing. Replace front cover and locking collar
on the input jack.
Audible Alarm
Operating
Environmental
Range
Dimensions
Power Adapter
100-240VAC
50-60 Hz
Figure 4. SCS CTA252 Replacement Wrist Strap Jacks
SCS
- 926 JR Industrial Drive, Sanford, NC 27332 • (919) 718-0000 • Website:
StaticControl.com
TB-9029
Page 4 of 6
© 2015 DESCO INDUSTRIES, INC.
Employee Owned
Safety Information
Read, understand, and follow all safety information
contained in this user guide prior to installation and use
of the SCS Wrist Strap and Ground Monitor. Retain this
guide for future reference.
Intended Use
This user guide covers the Wrist Strap and Ground
Monitor. The Wrist Strap and Ground Monitor has two
input jacks for monitoring impedance and voltage on a
dual conductor wrist strap. It monitors either one or two
metal grounds in a workstation. The Wrist Strap and
Ground Monitor operates from a universal AC power
adapter. These systems are typically installed on a
machine with multiple tools or on a work bench used for
ESD-sensitive electronic assembly or repair.
The systems must be installed as specified in this user’s
guide and are intended for use in an indoor commercial/
industrial environment. The systems have not been
evaluated for other uses or locations.
Warning
To reduce the risks associated with hazardous voltage,
which if not avoided could result in electrical shock
related injury; the risks associated with environmental
contamination, which if not avoided could result in
environmental contamination related injury; and the risk
associated with false test results, which if not avoided
could result in property damage:
• Read, understand and follow all safety information
contained in this user guide for installation and use.
Retain this guide for future reference.
To reduce the risks associated with hazardous volt-
age, which if not avoided could result in electrical shock
related injury:
• Replace power adapter if damaged with SCS
provided power adapter only.
• Do not modify or attempt to service the power
adapter or use it if damaged.
• Use the power adapter in an indoor dry location only.
Caution
To reduce the risks associated with environmental
contamination which, if not avoided, could result in minor
or moderate injury:
• Dispose of monitor in accordance with all applicable
local and government regulations.
Notice
To reduce the risks associated with property damage:
• Monitor must be checked periodically to verify each
monitor circuit is functioning correctly.
• The SCS Wrist Strap and Ground Monitor requires
a suitable ground to function properly. Refer to the
proper section of this User Guide for information on
connecting to a suitable electrical ground point.
• Do not use the Wrist Strap and Ground Monitor as a
primary method of electrical grounding – this device
is intended to monitor the ground connection only.
Regulatory Information
FCC
Note: This equipment has been tested and found to
comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC Rules. These limits are
designed to provide a reasonable protection against
harmful interference when the equipment is operated in
a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction
manual, may cause harmful interference to radio
communications. Operation of this equipment in a
residential area is likely to cause harmful interference
in which case the user will be required to correct the
interference at their own expense.
Modifications to this device shall not be made without the
written consent of SCS. Unauthorized modifications may
void the authority granted under Federal Communication
Rules and Industry Canada Rules permitting the
operation of this device.
ICES Statement
This Class A digital apparatus complies with Canadian
ICES-003.
Cet appareil numérique de la classe A est conforme à la
NMB-003 du Canada.
WEEE Statement
The following information is only for EU-member States:
The mark shown to the right is in compliance with Waste
Electrical and Electronic Equipment Directive 2002/96/
EC (WEEE). The mark indicates the requirement NOT
to dispose the equipment as unsorted municipal waste,
but use the return and collection systems according to
local law.
CE Statement
Meets CE (European Confomity) requirements.
cULus Statement
Meets UL Safety Requirements.
SCS
- 926 JR Industrial Drive, Sanford, NC 27332 • (919) 718-0000 • Website:
StaticControl.com
TB-9029
Page 5 of 6
© 2015 DESCO INDUSTRIES, INC.
Employee Owned
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