TB-9029
Page 4 of 6
© 2015 DESCO NDUSTRIES, NC.
Employee Owned
Specifications
Ground Impedance
Alarm Level
1 to 20 ohms
Wrist Strap Alarm -
Body Voltage
±2.5V on operator
Wrist Strap Alarm -
Operator Loop
Resistance
10 megohms on operator (plus
two 1 megohm resistors in the
end of the ground cord that
attaches to the wristband)
Output Signal Level
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.
Audible Alarm
Buzzer fault condition if enabled
Operating
Environmental
Range
Temperature: 50 to 110ºF (10 to
43ºC)
Humidity: 75% R.H. maximum
Dimensions
2.42” W x 2.45” L x 0.85” H
(61mm W x 62mm L x 22mm H)
Power Adapter
100-240VAC
50-60 Hz
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
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.
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.
Figure 4. SCS CTA252 Replacement Wrist Strap Jacks