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4.3
WirinG
pOwER SUpply REQUIREmENTS
Calculate the total gas detection system power
consumption rate in watts from cold start-up. Select a
power supply with adequate capability for the calculated
load. Ensure that the selected power supply provides
regulated and filtered 24 Vdc output power for the entire
system. If a back-up power system is required, a float-type
battery charging system is recommended. If an existing
source of 24 Vdc power is being utilized, verify that system
requirements are met. The acceptable voltage range is
18-30 Vdc measured at the input to the UD10.
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The power supply must meet the noise
requirements for HART systems. If noise or ripple
on the main power source could interfere with the
HART function, an isolated power source (Figure
7) is recommended. (For detailed information
regarding power supply specifications, refer
to the HART Communication Foundation’s
document “FSK Physical Layer Specification”
HCF_SPeC-54.)
wIRINg CABlE REQUIREmENTS
Always use proper cabling type and diameter for input
power as well as output signal wiring. 14 to 18 AWG
shielded stranded copper wire is recommended. Correct
wire size depends on the device and wire length. Refer
to the appropriate Appendix for additional information.
The maximum cable length from power source to UD10 is
2000 feet. Maximum cable length from UD10 to device/
STB sensor termination box is 2000 feet.
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The use of shielded cable in conduit or shielded
armored cable is highly recommended. In
applications where the wiring is installed in
conduit, dedicated conduit is recommended.
Avoid low frequency, high voltage, and
non-signaling conductors to prevent nuisance
eMI problems.
CautIon
The use of proper conduit installation techniques,
breathers, glands, and seals is required to prevent
water ingress and/or maintain the explosion-proof
rating.
wIRINg pROCEDURE
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The following section shows the output of the
UD10 wired to a generic 4-20 mA signal receiver
in various configurations. Since the UD10 can be
used with a variety of different detection devices,
information that is specific to each detector model
(wiring, calibration, HART menus, etc.) is covered
in an Appendix that is dedicated to that device.
Refer to the appropriate Appendix at the back of
this manual for specific information when wiring
the detection system. For information on devices
not covered in an Appendix, refer to the manual
provided by the device’s manufacturer.
Refer to Figure 4 for an illustration of the UD10 wiring
terminal board.
Figure 5 shows a UD10 Wired to a PLC using 3-Wire
Shielded Cable with a 4-20 mA Non-Isolated Sourcing
Output.
Figure 6 shows a UD10 Wired to a PLC using 4-Wire
Shielded Cable with a 4-20 mA Non-Isolated Sourcing
Output.
Figure 7 shows a UD10 Wired to a PLC with a 4-20 mA
Isolated Sourcing Output.
grease/lubrication
To ease installation and future removal, ensure that all
junction box covers and sensor threads are properly
lubricated. If the need arises for additional lubrication,
use either Lubriplate grease (see Ordering Information
for part number) or Teflon tape. Avoid the use of silicone
grease.
