Honeywell XNX - Page 34

XNX Universal Transmitter
Section 2 - Installation and Operation
32
• Fewerpowersources�
Disadvantages:
• Largerpowersourcewillbeneeded
• Ifapowersourcefails,severalmonitoringpointsfail�
Multiple Transmitters Connected in a “Daisy-Chain”
Conguration
Thiscongurationconsistsoftwoormoretransmittersinstalled
inaline�Thepowerconnectionsareinstalledasanextensionof
theprevioustransmitter,withthersttransmitterbeingtheonly
oneactuallywiredtothepowersource�
Class 2
Power Supply
Figure 31. Daisy-chained transmitters from one power supply
Advantages:
• Lesswireneededforinstallation
• Fewerpowersources�
Disadvantages:
• Requiresalargerpowersource
• Shorterdistancebetweenpowersourceandtransmitters�
• Ifapowersourcefails,severalmonitoringpointsfail�
Note: CSA/FMcertificationdoesnotcoverdaisy-chainedXNXcombus-
tiblegastransmitters.
Power Source Selection
Foreachtypeofinstallation,selectionofpowersupplyis
important�Powersuppliesareratedbyvoltageandpower�
ThenominalvoltageforallXNXtransmittersis24Vwiththe
powerrequired dependingonthenumberofpointsusingthe
samepowersupply�
XNX Universal Transmitter Maximum Power Consumption
Conguration
-40°C to +65°C -10°C to +65°C
HART
over
4-20mA
(watts)
HART over 4-20mA
with Relay, Modbus
®
, or
Foundation
TM
Fieldbus
(watts)
HART
over
4-20mA
(watts)
HART over 4-20mA
with Relay, Mod-
bus, or Foundation
Fieldbus
(watts)
XNXwithtoxic
sensors
5.1 6.2 3.4 4.5
XNXwithcatalytic
sensors
5.4 6.5 3.7 4.8
XNXwithinfrared
cartridge
5.4 6.5 3.7 4.8
XNXwithSearchpoint
OptimaPlus
8.6 9.7 6.9 8.0
XNXwith
SearchlineExcel
12.1 13.2 10.4 11.5
Asageneralguideline,thepowersupplyshouldbecapable
ofprovidingmorepowerthanisrequiredbytheinstallation�A
10wattpowersupplyisneforasingleXNXmVwithcatalytic
sensor(6�5wattsrequired,seethefollowingtable)butis
inadequateforasingleXNXIRwithSearchpointOptimaPlus(10
wattsrequired)�
Todeterminethewattagerequired,addthemaximumpower
requirementsofallthepointsthatwillsharethepowersupply�
Forexample,considerasystemwithtwoXNXmVtransmitters
withcatalyticsensors(6�5wattseach)andoneXNXIRwith