Honeywell XNX Technical Manual page 34

XNX Universal Transmitter
• 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"
Configuration
This configuration consists of two or more transmitters installed
in a line� The power connections are installed as an extension of
the previous transmitter, with the first 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
Section 2 - Installation and Operation
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
-40°C to +65°C
HART
Configuration
over with Relay, Modbus
4-20mA Foundation
(watts)
XNX with toxic
5.1
sensors
XNX with catalytic
5.4
sensors
XNX with infrared
5.4
cartridge
XNX with Searchpoint
8.6
Optima Plus
XNX with
12.1
Searchline Excel
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 fine 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
32
-10°C to +65°C
HART over 4-20mA
HART over 4-20mA HART
, or over
®
bus, or Foundation
Fieldbus 4-20mA
TM
(watts) (watts)
6.2 3.4
6.5 3.7
6.5 3.7
9.7 6.9
13.2 10.4
with Relay, Mod-
Fieldbus
(watts)
4.5
4.8
4.8
8.0
11.5