6
A100g
JULY 2017
*ADD 3.25” (83) FOR SHIELD
WIRING GAS SENSORS
Install the Hansen Gas Sensor in an area where operating
personnel can easily monitor the remote sensor. Refer
to
Gas Sensor Location
on page 3 for suggestions on
proper placement of Remote Sensors.
Use three-wire (VDC supply voltage), twisted pair shielded
cable such as Belden 8770 or equivalent to connect
the gas sensor to the gas monitor (page 15), GAS Alert
System (page 19), customer supplied PLC or computer
(page 20). When powering the gas sensor from a VAC
power supply use four-wire, twisted pair shielded cable,
such as Belden 82418 or equivalent. Connect the power
input wires to terminals ØV and +V. Set applied voltage
jumper to appropriate AC or DC position. Extreme Gas
Sensor requires an additional external 24V AC or DC
power supply wired with 18 AWG cable. Refer to Fig. 21
for wiring details. Connect the signal wire to terminal I
for 4-20mA output or V terminal for 1-5 volt output. The
4-20mA output is best for long distances to the monitor
and where electrical noise is a problem. The voltage output
is for short distances within 10 feet (3 m) of the monitor.
The maximum 4-20mA cable length is 1000 ft (300 m).
Under no circumstances should the gas sensor low
voltage signal wires be in a common conduit, tray or
wiring panel with power wiring over 48 volts. Do not run
wires near variable frequency drive (VFD) equipment.
When using the gas sensors connected directly to a
customer supplied PLC or computer, refer to Fig. 20
for wiring details.
Hansen recommends backup of gas detection system
with an uninterruptable power supply to provide battery
backup in the event of a power failure.
INSTALLATION
Mounting the gas sensor varies by model. Refer
to
Installation Dimensions
below for mounting
requirements.
SENSING ELEMENT
Typical sensor life is based on normal operating
conditions. Exposure to the target gas will shorten these
times. The typical sensor life of the electrochemical gas
sensor element is 1 to 2 years; typical sensor life for
semiconductor element is 2 years; and typical sensor
life for infrared element is 5 to 7 years. Recalibration
should be performed at least every 6 months. Calibration
can be performed locally at sensor installation site. If
desired results cannot be achieved or if signal reads
0.5mA, replacement of the sensor element may be
required. See
Sensor Element Replacement
section
for further instruction.
Note: Insurance companies, local and state agencies
may require more frequent testing and calibration; refer
to insurance carrier mandates as well as local and state
codes.
INSTALLATION DIMENSIONS
INCHES (MM)
FIG. 8
BASIC
STANDARD & HARSH
EXTREME
EXPLOSION PROOF
