USER GUIDE TB-9025
746 Wrist Strap Tester
Operation and Maintenance
Power Sources
Figure 1. 746 Wrist Strap Tester.
Description
The design of the 746 Wrist Strap Tester allows for
testing of wrist straps while being worn by a person or
testing of the individual wrist strap components. The 746
Wrist Strap Tester can be mounted to a wall or used as FIgure 2. 746 Wrist Strap Tester installation diagram.
a portable piece of test equipment. It operates from a
120VAC source through an AC adapter, or a standard 9 1A. 9 volt backup battery - To correctly install the
volt battery. An internally set resistance range extends battery, follow these instructions:
from 750 Kilohms to 10 megohms . If the wrist strap Attach the battery snap connector to the battery. Place
resistance when tested is within this range, a green the battery into the compartment, locating the snap
LED will illuminate. If outside this range, a red LED will connector at the opposite end of the compartment
illuminate. from where the battery wires come through the
housing, keeping the wires along the top edge of the
Wrist straps are the primary method used to minimize compartment. Run the battery wires along the side of the
charge generation on the human body. They must be battery and tuck them down between the housing and
able to drain this charge as rapidly as it is generated. the battery so that the wires clear the cover. Use a small,
For this reason, it is important to test wrist straps on a straight blade screwdriver to gently push the battery
regular basis to ensure they are functioning properly. wires down below the lip of the compartment. Slide and
The test results should be recorded. The form on page 3 lock the cover into place. When changing the battery, the
of this users guide can be used as a logbook. battery cover must be removed carefully. To remove the
battery cover, slide back the cover slightly. Insert a small,
straight blade screwdriver into the opening immediately
Specifications
over the tab area beneath the word OPEN. Press down
Base Unit 3.75" W x 1.5" H x 6.25" L with the screwdriver while sliding the cover off. You must
(95 mm W x 38 mm H x 158 use a screwdriver to remove the battery cover.
mm L)
1B. AC/DC Adapter
Weight 7.5 oz. (213g) without battery
Connect the AC/DC adapter to the jack at the base of
AC/DC Adapter 9VDC regulated 75mA
the unit. Plug the adapter into a 120VAC outlet.
Caution: If the AC/DC adapter is plugged into the 746
Accuracy 10% (10 megohms limit)
Wrist Strap Tester, it must also be plugged into the wall
20%-0% (750 kilohms limit)
outlet to allow the unit to function. If the 746 Wrist Strap
Measurement Voltage 14VDC 1VDC (open circuit)
Tester is to be powered with battery only, the AC/DC
adapter MUST be disconnected from the DC input jack
Installation (1B) on the tester.
The paragraph numbers below are referenced in Figure
2. Battery Indicator
2.
SCS - 926 JR Industrial Drive, Sanford, NC 27332 (919) 718-0000 Website: StaticControl.com
2015 DESCO INDUSTRIES, INC.
TB-9025 Page 1 of 3
July 2015
Employee Owned3. Jack Cover
Verification Procedure
Insert the plastic cover into the yellow wrist strap plug-
The 746 Wrist Strap Tester cannot be adjusted by
in jack that is not being used. The jack on the right fits
the user, but the following steps can be used to verify
standard banana plugs used in North America. The 746
that the 746 Wrist Strap Tester is operating within its
Wrist Strap Tester is now ready for use.
specification.
4. Wall Mounting
Equipment needed
The enclosed SCS Dual Lock Wall Mounting System
1. Resistance substitution box, 700 kilohms - 11
adhesion discs must be screwed onto the wall, using
megohms, accuracy < 2%.
the attached template, approximately 1.5 m (5 ft.) off
2. Two lead wires to connect the resistance box to the
the floor. Drill three holes of 5 mm (0.2 in.) diameter at
746 Wrist Strap Tester.
marked locations.
Checking wrist strap test circuit
5. The enclosed Dual Lock Adhesion Strip must be cut
Connect the resistance substitution box to the tester
in two halves and adhered to the rear of the 746 Wrist
as shown in Figure 3. Adjust the resistance substitution
Strap Tester, parallel to the bottom edge and below the
box to each value of resistance indicated in the test
battery compartment. Make sure the area on the 746
table below and press contact plate A. The LEDs will
Wrist Strap Tester where the adhesion strips are to be
indicate, as shown below, if the unit is functioning within
placed is free of dust and dirt. Press the back of the case
specifications.
firmly against the discs to secure the tester to the wall.
Resistance Resistance range LED
6. For removal, lift the 746 Wrist Strap Tester at the two
Substitution box of the tester Indication
top corners with both hands.
settings
Testing Procedure
750 kilohms 750 kilohms Red
7. Wrist Band/Cord Test
900 kilohms Green
Put the wrist band on with the ground cord attached and
insert the ground cord banana plug into the yellow wrist
9.0 megohms 10 megohms Green
strap plug-in jack.
11.0 megohms Red
8. Depress the metal contact plate and hold.
The 750 kilohms threshold is approximate for that range
9. One of the LED indicators will illuminate. An
and could vary slightly. Actual threshold resistances are
illuminated green LED indicates that the wrist strap
not listed.
assembly performs within the resistance range of 750
kilohms to 10 megohms. If a red LED is illuminated, the
resistance of the wrist strap assembly may be outside
the range of 750 kilohms to 10 megohms. To check the
resistance of the ground cord, leave the banana plug
end attached to the tester. Unsnap the cord from the
wrist band. Place the metal side of the ground cord snap
end against the metal contact plate. Depress the plate
and check to see which LED illuminates. If the red LED
illuminates, the ground cord is outside of the resistance
range. If the green LED illuminates, the ground cord is
OK but the wrist band may need to be replaced. NOTE:
In some cases, a high contact resistance between the
persons skin and the wrist band will cause the tester
to indicate a red LED (greater than 10 megohms). This
higher resistance may be caused by dry skin or hair
on the wearers wrist. A loose fitting wrist band can
FIgure 3. Checking wrist strap test circuit.
also cause intermittency or high resistance. If these
conditions do not exist, a new wrist band should be
obtained and tested on the person.
SCS - 926 JR Industrial Drive, Sanford, NC 27332 (919) 718-0000 Website: StaticControl.com
2015 DESCO INDUSTRIES, INC.
TB-9025 Page 2 of 3
Employee Owned