Honeywell XNX - 4.8.2 Connecting Generic mA Device

XNX Universal Transmitter
Section 2 - Installation and Operation
31
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�
Loads
Theuseofhighinrushorinductiveloadsmayaffectthe
performanceofthetransmitter�Forbestreliabilityuseresistive
loadsonly�
2.2.2 Distance Considerations for Installation
Providingpowertothetransmitteristhefactorthatwill
determinethemaximumdistanceoftheinstallation�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;
specically,howmanytransmitters/sensorsaredrawingpower
fromthesamepowersupplyandwhetherthesetransmittersare
usingthesamepairofwires(“daisy-chain”)orhavetheirown
connections�
Types of Installations
Therearethreebasictypesofinstallation:asingletransmitter;
multipletransmittersconnectedtoasinglepowersource;and
multipletransmittersconnectedina“daisy-chain”conguration�
Single Transmitter
Thisisthesimplesttypeofinstallation�Itconsistsofasingle
XNXtransmitterinstallationperpowersource�
Class 2
Power Supply
Class 2
Power Supply
Class 2
Power Supply
Figure 29. Single Transmitter Installation
Advantages:
• Maximumdistancebetweenpowersourceandtransmitter
• Smallerpowersource
• Ifapowersourcefails,onlyonemonitoringpointfails�
Disadvantage:
• Multipletransmittersrequiremultiplepowersources�
Multiple Transmitters Connected to a Single Power Source
Thisistwoormoretransmitterssharingasinglepowersource
witheachtransmitterhavingitsowndedicatedwiringtothe
powersource�
Class 2
Power Supply
Figure 30. Multiple Transmitters Powered by a Single Power Supply
Advantages:
• Maximumdistancebetweenpowersourceand
transmitters