TB-9029
Page 2 of 6
© 2015 DESCO NDUSTRIES, NC.
Employee Owned
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
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.
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.
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
Figure 2. Rear view of Wrist Strap and Ground Monitor