Desco 94332 Installation Manual

Ground Gard 5

TECHNICAL BULLETIN TB-5537

Operation, Installation, and Maintenance

Packaging

Item 94393

1 Ground Gard 5 Monitor
2 Remote Operator Module
1 Power Adapter
2 Remote Operator Cables
1 Mat Ground Cord
1 Push and Clinch Snap

94340

94393

Figure 1. SPI Ground Gard 5

Description

The Ground Gard 5 is a wrist strap and ground ­monitoring device for the electronics workstation. When
used correctly, it will provide a static safe and properly
grounded work environment. It is designed to constantly
monitor two capacitance type single wire wrist straps
using a remote module for each user. A Ground Sense
circuit with looping capability is also provided to
constantly monitor the ground condition of bench tops,
mats, wrist straps and the Ground Gard 5 unit itself.

The Ground Gard 5 is available in the following model.
the part numbers are listed below:

Item Description

94393 Ground Gard 5 with Buzzer
94332 Power Supply, 12 Volt, 3 Prong (for use with 94393)
94340 Remote Operator Module, Under Bench

2 Velcro® Strips
4 Screws
1 Certicate of Calibration

Installation:

1. GROUND GARD 5 MONITOR:

The Ground Gard 5 Monitor is designed to not reduce
valuable work area and should be mounted at eye level
above the workstation, either on a post or shelf support.
A double-sided adhesive Velcro attachment is provided
to hold the lightweight head in place.

2. GROUND CONNECTION:

For item 94393 the ground connection is made through
the third prong of the 3-conductor power supply.

Caution: The total amount of resistance through all

monitored parts should not exceed 10.0 megohms total.

3. REMOTE OPERATOR MODULES:

The remote operator module can be mounted at the front
of the work surface, usually under the
tabletop and ush with the front edge.
Two screws for each unit are provided
for mounting. Connect each remote to
the monitor unit using the telephone cable with RJ11
connectors.

4. POWER UP TEST:

After installing the Monitor, remote units, and making the
necessary connections without the wrist straps
connected, the unit should POWER UP with the ground
sense LED indicator GREEN, the wrist strap LED’s OFF
and the audible alarm SILENT. If you have no response
to power or a red LED, check AC outlet for proper ground
or refer to trouble-shooting section.

Made in America

The Ground Gard 5 will alarm if preset values are
exceeded forcapacitance, high resist and ground loss
conditions. The grounding system is redundant and will
still provide a limited grounding even if the utility ground
is lost and the system is in an alarm state.

ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com

TB-5545 Page 1 of 4 Revision May 2009

TB-5537 September 2010 Page 1 of 3

© 2009 DESCO INDUSTRIES INC.
Employee Owned

ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com

© 2010 DESCO INDUSTRIES INC.

Employee Owned

PARK SNAP

The audible alarm is designed to alert both operator and
supervisor. The Park Snap feature provides a means
for an operator to disconnect when normally leaving the
work area, without the audible alarm sounding, and it
provides a means of wrist cord storage (visual red LED
will illuminate). You may also disconnect coil cord by
unplugging banana plug from the remote.

Remote Module Description:

Inside the remote module is an infrared sensor that
reacts to the insertion of a wrist strap wire with a banana
plug. When the banana plug is inserted, the base unit is
activated for that remote module. The monitor LED for
the left or right wrist strap will light showing the condition
of that strap. If correct, the LED should be GREEN.

Should the wrist strap fail, be worn incorrectly, or
removed by the operator, the red indicator will ash,
calling attention to a problem. Should the ground
connection be lost, the red light and alarm will be
activated. The monitor is continuous and even a
momentary break will cause alarms. The remote module
is set at the factory to allow for sensitivity of the
“average” human body model.

Calibration Procedures Using
Model 94370

With coils wires connected to test unit and each remote,
observe the following. Both lights should illuminate green
on the monitor, with no buttons depressed on the tester.
Pressing button one or four should cause the left or right
wrist strap togo red, simulating a high resist condition on
the wrist strap. This shows the wrist remote is properly
calibrated.

If the above conditions are not met, make the following
adjustment:

With buttons one and four not depressed, the LED
display on the monitor should be in a green condition. If
not, nd the adjusting port on the remote. Inside there is
an adjusting trim pot. Turn the trim pot slightly until the
head module LED turns green.

Step One: Turn the pot until the green LED triggers red,

then ease back until LED triggers green.

Step Two: Press the corresponding button on the test

unit and the LED will go red on the monitor. This shows
the Ground Gard 5 remote is in a proper calibration.

Note: If the unit does not go red, go back to step one

and repeat procedure.

Installation Adjustments:

Should your system alarm without obvious cause, rst
troubleshoot and verify all connections. If all the
connections are correct, the base unit should be
adjusted to compensate for a different HBM (human
body model). We preset the units at the factory at 100pF
and your operator might be out of the tolerance range
caused either by body chemistry, bulk capacitance or
impedance differences.

Follow these steps to adjust and personalize the base
unit:

Locate the small hole in the face of the remote module
(factory adjustment label may cover hole). Inside this
hole is a trim pot device that is adjustable by using a
small at-head screwdriver.

With the system set up and operating, and the operator’s
wrist strap connected to the remote module:

1. Turn the pot until the green light activates. Disconnect
the wrist wire from the band. The unit should alarm and
activate the red light. If not, turn the trim pot until the
red light activates. Reconnect the wire to the wrist band
and the alarm should cease and the green light should

activate.

2. Turn the pot until the green light begins. Disconnect
the wrist wire from the band. The unit will alarm and
activate the red light. If not, turn the trim pot until the red
light activates. Reconnect the wire to the wristband and
the alarm will cease, the green light will activate.

GROUND SENSE OR TABLE TOP MONITORING:

The Ground Gard 5 includes a ground monitoring system
that assures a positive ground connection for the
workstation. The resistance range is preset at the factory
to monitor that the connection to ground is within the
resistance range of .01 to 10 megohms. A visual and/or
audio alarm will verify safe or fault conditions.

CONDITION INDICATOR
Ground Sense

Safe - Properly Grounded - LED Green
with Resistance less - No Audible Alarm
than 10 Meg.
Hi resist - Grounded, but - LED Oscillate Green to
Resistance exceeds 10 Meg. Amber or Flashing Red

- Audible Alarm
Fault - Loss of 1 or both - LED Flashing Red
redundant grounds, failure - Audible Alarm
of monitor, worktop, mat, etc.

ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com

TB-5545 Page 2 of 4 Revision May 2009

TB-5537 Page 2 of 3

© 2009 DESCO INDUSTRIES INC.
Employee Owned

ESD Systems.com • 432 Northboro Road Central • Marlboro, MA 01752 • [phone] • Fax [phone] • Website: ESDSystems.com

© 2010 DESCO INDUSTRIES INC.

Employee Owned