Detcon TP-624C - Manual (Page 12)

3.5.6 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 location that is diff i-
cult to access. Such a location creates problems for maintenance and calibration activities. Detcon provides the TP-
624C sensor in a remote-mount conf iguration in which the sensor (Model TP-624C-RS) and the transmitter (Model
TP-624C-RT) are provided in their own condulet housing and are interfaced together with a four conductor cable.
Reference f igure 5A below for wiring diagram.
Remote Mounting Configuration - Heater Voltage Adjustment
When a sensor is remote mounted, consideration must be given to the length and gauge of cable used and how it
affects the sensor heater voltage. Fourteen to sixteen gauge wire is recommended. 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 3.6.2 for instructions.
3.6 S
TART
U
P
Upon completion of all mechanical mounting and termination of all f ield wiring, apply system power and observe
the following normal conditions:
a) TP-624C “Fault” LED is off.
b) A temporary upscale reading may occur as the sensor heats up. This upscale reading will clear to “0”
ppm within 1-2 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 contacting
the sensor f ilm while it is off power, and thus helps to 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 acces-
sory 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 mandatory) to
use the desiccant caps during long periods without power.
Detcon Model TP-624C Hydrogen Sulfide Sensor PG.12
1 2 3 4
W
H
T
B
L
K
Y
E
L
B
LU
Remote Transmitter
TP-624C-RT
Remote Sensor
FP-624C-RS
W
H
T
B
L
K
Y
E
L
B
LU
Measure Heater V oltage
From White (1) to Black (2)
Target voltage is 5.25v
± .05 v
Figure #5A