Detcon FP-700 - Manual (Page 13)

Model FP-700
FP-700 Instruction Manual Rev. 3.0 Page 9 of 40
NOTE: A conduit seal is typically required to be located within 18" of the J-Box and Sensor
Assembly. Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.
Plug any unused
ports
Explosion Proof
Housing
(J-Box) Drain
FP-700
Sensor
Assembly
Conduit
"T" EYS Seal Fitting
MODEL
FP-700
detcon inc.
LEL Sensor
(+
)
m
A
(-
)
A
(+
)
B
(-
)
Wiring to
Sensor Assembly
W
h
t
B
lu
R
e
d
G
rn
B
lk
Explosion
Proof
Junction Box
(+)
mA
(-)
N/U
A(+)
B(-)
Customer
Supplied Wiring
Transient Protection Module
(TPM) P/N 500-003087-100
Mount TPM in Explosion
Proof Enclosure to ground
unit properly. Mount to
bottom of enclosure using
6-32 screws.
6-Pin Pheonix Plug
P/N 306-175705-100
Figure 10 Typical Installation
NOTE: Any unused ports should be blocked with suitable ¾” male NPT plugs. Detcon
supplies one ¾” NPT male plug with their accessory J-box enclosures. If connections are other
than ¾” NPT, use an appropriate male plug of like construction material.
2.6 Field Wiring
Detcon Model FP-700 sensor assemblies require three conductor connections between power supplies and host
electronic controller’s 4-20mA output, and two conductor connections for the Modbus™ RS-485 serial
interface. Wiring designations are + (DC), – (DC), mA (sensor signal), and Modbus™ RS-485 A (+), and B (-
). Maximum wire ohmic resistance between sensor and 24VDC source is defined below. Maximum wire size
for termination in the Detcon J-Box accessory is 14 gauge.
Max Resistance drop on red and black wire is 10 ohms. This considers wire diameter, wire length and
maximum operation temperature.
Max loop load resistance between green and black wire is 500 ohms. Minimum loop load resistance between
green and black wire is 100 ohms. This is considers wire diameter, wire length, max operating temperature
and selected termination resistor.