Honeywell XNX-AM Series, Техническое руководство

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XNX Universal Transmitter
Installation and Operation 33
Caution: Before wiring the transmitter, confirm that the correct personality and
communication boards are installed.
CAUTION
!
General Wiring Considerations
For proper operation of the transmitter and sensor technologies,
consideration of wiring-induced voltage drops, transient
electrical noise, and dissimilar earth ground potentials is
imperative in the design and installation of the system.
Warning: The sensor must be earthed/grounded for intrinsic safety, electrical safety
and to limit the effects of radio frequency interference. Earth/ground points are provided
inside and outside the unit. EMI note for applications using shielded cable: Cable shield
must provide 90% coverage of the wiring. Cable shield terminations must be made at the
cable glands with suitable EMI type glands. Avoid terminating cable shields at the Earth
ground lug inside the XNX enclosure. In cases where wiring is in pipe, a shielded cable is
not required. The external terminal is only a supplemental bonding connection where local
authorities permit or require such a connection.
WARNING
!
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When wiring for DC power, 4-20mA signal, remote wiring to
sensors must be sized sufficiently to provide adequate voltages
for the line length and the loads that will be used.
The use of high inrush or inductive loads may affect the
performance of the transmitter. For best reliability use resistive
loads only.
Isolation
Isolate the power and signal-carrying conductors.
Circuit Protection
Supply circuits must provide over-current protection. Consider
inrush current in specifying any DC supply. Power supply range
is 16 to 32 VDC for EC and mV versions, 18 to 32 VDC for
Searchpoint Optima Plus and Searchline Excel, and 16 to 32
VDC depending on the limitations of the device for the generic
4-20mA input.
Distance Considerations for Installation
Adequately powering the transmitter is the factor that
determines an installation’s maximum distance. The 4-20 mA
output signal will easily handle the distance back to the control
equipment.
The primary factors determining distance are the minimum oper-
ating voltage of the transmitter and/or sensor; the maximum
current draw of the transmitter/sensor, the resistance of the
wire used, the power supply voltage, and the current capacity
of power supply. An additional consideration is the type of
installation; specifically, how many transmitters/sensors are
drawing power from the same power supply and whether these
transmitters are using the same pair of wires (“daisy-chained”) or
have their own connections.