Line of Sight Infrared Hydrocarbon Gas Detector AutroPath HC800 , 116-P-HC800/IGB, Rev. A, 2016-03-03
P/N 95-8744, v4.2 , rev. 3/16
Autronica Fire and Security AS
Page 19
PoweR wIRING SIze AND mAxImum LeNGtH
1. To ensure proper operation, AutroPath HC800
power terminals and 4–20 mA terminals must
receive 18 Vdc minimum. 24 Vdc is recommended.
2. Always determine voltage drops that will occur to
ensure that 24 Vdc is delivered to the AutroPath
HC800.
3. Normally, nothing smaller than 18 AWG (1.0 mm
2
)
is recommended by Autronica Fire and Security for
AutroPath HC800 power cabling.
Wire size requirements are dependent upon power
supply voltage and wire length.
The maximum distance between the AutroPath HC800
detector and its power supply is determined by the
maximum allowable voltage drop for the power wiring
loop. If the voltage drop is exceeded, the device will not
operate. To determine the maximum power loop voltage
drop, subtract the minimum operating voltage for the
device (18 Vdc) from the minimum output voltage of the
power supply.
To determine the actual maximum wire length:
1. Divide the maximum allowable voltage drop by the
maximum current draw of the AutroPath HC800
(0.771 A),
2. Divide by the resistance of the wire (ohms/foot
value available in wire manufacturer’s specification
data sheet),
3. Divide by 2.
For example: Consider an installation using 18 AWG
wiring with a power supply providing 24 Vdc.
Power supply voltage = 24 Vdc,
AutroPath HC800 minimum operating voltage = 18 Vdc
24 – 18 = 6 Vdc
Maximum Voltage Drop = 6
Maximum Current = 0.771 A
Wire Resistance in Ohms/Foot = 0.006523
6 ÷ 0.771 ÷ 0.006523 ÷ 2 = 596 feet
oPtIoNAL ReLAyS
Optional relay contacts are “dry,” meaning that the
installer must provide the voltage to the common
terminal of the relay output.
AC voltage should not be switched directly using the
AutroPath HC800 relays. The use of an external relay
is required if AC voltage must be switched by the
AutroPath HC800 relays. Note: External relay is not
covered by any Certifications.
In order to change alarm relay settings from the factory
default settings, it is recommended to use a HART
Field Communicator. Contact the factory for further
assistance.
NoTe
Refer to “Alarm Relays” in the “Specifications”
section of this manual for important information
regarding alarm relays.
wIRING PRoCeDuRe
For systems using conduit, modules must be wired
using a short piece of suitable flexible conduit to allow
optical alignment of the modules. Conductor insulation
should be stripped off with a bare conductor length
of 0.2 inch (5 mm) minimum and 0.35 inch (9 mm)
maximum. Screw terminal torque range is 3.5–4.4 lb.-
in. (0.4–0.5 N•m).
Cable shield, if used, should be properly terminated. If
not terminated, clip the shield wire off short and insulate
it within the detector housing to prevent the shield wire
from accidentally contacting the detector housing or
any other wire.
Figure 14 shows the wiring terminal strip located inside
the detector’s integral junction box.
NoTe
The AutroPath HC800 housing must be electrically
connected to earth ground. A dedicated earth
ground lug is provided for this purpose.
Figure 12 shows the wiring terminal configuration for
the AutroPath HC800 transmitter.
Figure 15 shows the wiring terminal configuration for
the AutroPath HC800 receiver without relays.
Figure 13 shows the wiring terminal configuration for
the AutroPath HC800 receiver with relays.
Figures 16 through 19 show the 4–20 mA output of the
AutroPath HC800 receiver in various wiring schemes.
See Figure 20 for benchtop test wiring.
