Detcon TP-424C - Manual (Page 9)

Remote Mounting Applications
Some sensor mounting applications require that the gas sensor head be remotely mounted away from the
sensor transmitter. This is usually true in instances where the gas sensor head must be mounted in a loca-
tion that is difficult to access. Such a location creates problems for maintenance and calibration activities.
Detcon provides the TP-424C sensor in a remote-mount configuration in which the sensor (Model TP-424C-
RS) and the transmitter (Model TP-424C-RT) are provided in their own condulet housing and are inter-
faced together with a three conductor cable. Reference the figure below for wiring diagram.
Remote Mounting Configuration - Heater Voltage Adjustment
When a sensor is remote mounted, consideration must be given to the lengths of cable used and how it
affects the sensor heater voltage. Differing lengths of cables will have varying amounts of resistance which will
shift the sensor heater voltage. Because of this, the heater voltage will need to be adjusted after initial power
up. Replacement of the sensor will also require readjusting the heater voltage. See section 3.7.2 for instruc-
tions.
3.7 S TART UP
Upon completion of all mechanical mounting and termination of all field wiring, apply system power and
observe the following normal conditions:
a) Transmitter “Fault” LEDs (Heater Fault and Signal Fault) are off.
b) Detcon controller (if applicable) “Fault” LED is off.
c) A temporary upscale reading will occur as the sensor heats up. This upscale reading will clear to "0"
ppm within 5-10 minutes of turn-on, assuming there is no gas in the area of the sensor.
Important Note:
A desiccant cap is attached to the sensor housing during storage and shipping. This prevents H20 from con-
tacting the sensor f ilm while it is off power, and thus helps to avoid damage and retain the stability of the
factory span calibration. Remove the desiccant cap 5~10 minutes after applying power to the sensor, then
install the weatherproof splashguard accessory supplied with your sensor.
Store the desiccant caps in a sealed container (i.e., zip-lock bag) for future use. It is advised (but not manda-
tory) to use the desiccant caps during long periods without power (more than 1 day).
Detcon Model TP-424C Hydrogen Sulfide Sensor PG.9
1 2 3 4
W
H
T
B
L
K
Y
E
L
B
LU
Remote Transmitter
TP-424C-RT
Remote Sensor
TP-424C-RS
WHT
BLK
YEL
BLU
Plug unused port
with 3/4 NPT plug.
Measure Heater V oltage
From White (1) to Black (2)
Target voltage is 5.25v
±.05 v