SCS 746 User manual

TB-9025 Page 1 of 3 © 2015 DESCO INDUSTRIES, INC.
Employee Owned
SCS - 926 JR Industrial Drive, Sanford, NC 27332 • [phone] • Website: StaticControl.com
746 Wrist Strap Tester
Operation and Maintenance
USER GUIDE TB-9025
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
a portable piece of test equipment. It operates from a
120VAC source through an AC adapter, or a standard 9
volt battery. An internally set resistance range extends
from 750 Kilohms to 10 megohms . If the wrist strap
resistance when tested is within this range, a green
LED will illuminate. If outside this range, a red LED will
illuminate.
Wrist straps are the primary method used to minimize
charge generation on the human body. They must be
able to drain this charge as rapidly as it is generated.
For this reason, it is important to test wrist straps on a
regular basis to ensure they are functioning properly.
The test results should be recorded. The form on page 3
of this user’s guide can be used as a logbook.
Specications
Base Unit 3.75" W x 1.5" H x 6.25" L
(95 mm W x 38 mm H x 158
mm L)
Weight 7.5 oz. (213g) without battery
AC/DC Adapter 9VDC regulated 75mA
Accuracy ± 10% (10 megohms limit)
± 20%-0% (750 kilohms limit)
Measurement Voltage 14VDC ± 1VDC (open circuit)
Installation
The paragraph numbers below are referenced in Figure
2.
July 2015
Power Sources
FIgure 2. 746 Wrist Strap Tester installation diagram.
1A. 9 volt backup battery - To correctly install the
battery, follow these instructions:
Attach the battery snap connector to the battery. Place
the battery into the compartment, locating the snap
connector at the opposite end of the compartment
from where the battery wires come through the
housing, keeping the wires along the top edge of the
compartment. Run the battery wires along the side of the
battery and tuck them down between the housing and
the battery so that the wires clear the cover. Use a small,
straight blade screwdriver to gently push the battery
wires down below the lip of the compartment. Slide and
lock the cover into place. When changing the battery, the
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
over the tab area beneath the word “OPEN.” Press down
with the screwdriver while sliding the cover off. You must
use a screwdriver to remove the battery cover.
1B. AC/DC Adapter
Connect the AC/DC adapter to the jack at the base of
the unit. Plug the adapter into a 120VAC outlet.
Caution: If the AC/DC adapter is plugged into the 746
Wrist Strap Tester, it must also be plugged into the wall
outlet to allow the unit to function. If the 746 Wrist Strap
Tester is to be powered with battery only, the AC/DC
adapter MUST be disconnected from the DC input jack
(1B) on the tester.
2. Battery Indicator

TB-9025 Page 2 of 3 © 2015 DESCO INDUSTRIES, INC.
Employee Owned
SCS - 926 JR Industrial Drive, Sanford, NC 27332 • [phone] • Website: StaticControl.com
3. Jack Cover
Insert the plastic cover into the yellow wrist strap plug-
in jack that is not being used. The jack on the right ts
standard banana plugs used in North America. The 746
Wrist Strap Tester is now ready for use.
4. Wall Mounting
The enclosed SCS Dual Lock Wall Mounting System
adhesion discs must be screwed onto the wall, using
the attached template, approximately 1.5 m (5 ft.) off
the oor. Drill three holes of 5 mm (0.2 in.) diameter at
marked locations.
5. The enclosed Dual Lock Adhesion Strip must be cut
in two halves and adhered to the rear of the 746 Wrist
Strap Tester, parallel to the bottom edge and below the
battery compartment. Make sure the area on the 746
Wrist Strap Tester where the adhesion strips are to be
placed is free of dust and dirt. Press the back of the case
rmly against the discs to secure the tester to the wall.
6. For removal, lift the 746 Wrist Strap Tester at the two
top corners with both hands.
Testing Procedure
7. Wrist Band/Cord Test
Put the wrist band on with the ground cord attached and
insert the ground cord banana plug into the yellow wrist
strap plug-in jack.
8. Depress the metal contact plate and hold.
9. One of the LED indicators will illuminate. An
illuminated green LED indicates that the wrist strap
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
person’s 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 wearer’s wrist. A loose tting wrist band can
also cause intermittency or high resistance. If these
conditions do not exist, a new wrist band should be
obtained and tested on the person.
Verication Procedure
The 746 Wrist Strap Tester cannot be adjusted by
the user, but the following steps can be used to verify
that the 746 Wrist Strap Tester is operating within its
specication.
Equipment needed
1. Resistance substitution box, 700 kilohms - 11
megohms, accuracy < 2%.
2. Two lead wires to connect the resistance box to the
746 Wrist Strap Tester.
Checking wrist strap test circuit
Connect the resistance substitution box to the tester
as shown in Figure 3. Adjust the resistance substitution
box to each value of resistance indicated in the test
table below and press contact plate A. The LEDs will
indicate, as shown below, if the unit is functioning within
specications.
Resistance
Substitution box
settings
Resistance range
of the tester
LED
Indication
750 kilohms 750 kilohms Red
900 kilohms Green
9.0 megohms 10 megohms Green
11.0 megohms Red
The 750 kilohms threshold is approximate for that range
and could vary slightly. Actual threshold resistances are
not listed.
FIgure 3. Checking wrist strap test circuit.

TB-9025 Page 3 of 3 © 2015 DESCO INDUSTRIES, INC.
Employee Owned
SCS - 926 JR Industrial Drive, Sanford, NC 27332 • [phone] • Website: StaticControl.com
Limited Warranty, Warranty Exclusions, Limit of
Liability and RMA Request Instructions
See the SCS Warranty -
http://staticcontrol.descoindustries.com/warranty.aspx
Figure 4. 746 Wrist Strap Tester logbook.
Safety Information
Read and Understand all Safety Information Before
Operating this Equipment.
Intended Use: The SCS 746 Wrist Strap Tester was
designed and tested to be used for measuring the
electrical resistance of single-conductor wrist strap
assemblies.
Caution:
Battery Replacement: The use of an 9V alkaline battery
is recommended for the SCS 746 Wrist Strap Tester.
Battery Disposal: Dispose of batteries in accordance
with state and local requirements.
If the AC/DC adapter is plugged into the 746 Wrist Strap
Tester , it must also be plugged into the wall outlet to
allow the unit to function. If the 746 Wrist Strap Tester
is to be powered with battery only, the AC/DC adapter
MUST be disconnected from the DC input jack (1B) on
the tester.
Warning:
• Battery may explode if misused. Do not recharge or
disassemble.
• Do not dispose of in re.
Regulatory Information
WEEE Statement
The following information is only for EU-members 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.
All statements, technical information, and
recommendations related to SCS’s products are
based on information believed to be reliable, but the
accuracy or completeness is not guaranteed. Before
using this product, you must evaluate it and determine
if it is suitable for your intended application. You
assume all risks and liability associated with such use.
Any statements related to the product which are not
contained in SCS’s current publications, or any contrary
statements contained on your purchase order shall
have no force or effect unless expressly agreed upon, in
writing, by an authorized ofcer of SCS.