Detcon TP-624D - Manual (Page 13)

Model TP-624D
TP-624D Instruction Manual Rev. 0.4 Page 9 of 40
NOTE: The Detcon Warranty does not cover water damage resulting from water leaking into
the enclosure.
Figure 8 Typical Installation
NOTE: Any unused ports should be blocked with suitable ¾” male NPT plugs. Detcon
Supplies one ¾” NPT male plug with each J-box enclosure. If connections are other than ¾”
NPT, use an appropriate male plug of like construction material.
2.6 Field Wiring
Detcon Model TP-624D solid-state H
2
S sensor assemblies require up to five conductor connections between
power supplies and host electronic controller. Wiring designations are DC+, DC-, MA (sensor signal), Modbus
A and Modbus B. If the MA signal is not needed, its terminal may be left unconnected. If the MA signal is
not needed, a 250 ohm load resistor should be connected between the 4-20mA and the Power ‘-‘ terminals to
properly terminate the signal. The maximum wire length between sensor and 24VDC source is shown in the
Table below. The maximum wire size for termination in the Junction Box is 14 AWG.
Table 2 Wire Gauge vs. Distance
AWG Wire Dia. Meters Feet
Over-Current
Protection
22 0.723mm 700 2080 3A
20 0.812mm 1120 3350 5A
18 1.024mm 1750 5250 7A
16 1.291mm 2800 8400 10A
14 1.628mm 4480 13,440 20A
NOTE 1: Wiring table is based on stranded tinned copper wire and is designed to serve as a
reference only.
NOTE 2: Shielded cable is required for installations where cable trays or conduit runs include
Customer
Wiring
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Wiring to
H2S Sensor
Power (+ -)
4-20 mA
RS-485 (A,B)
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