Honeywell XNX Technical Manual page 33

XNX Universal Transmitter
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;
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-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" configuration�
Section 2 - Installation and Operation
Single Transmitter
This is the simplest type of installation� It consists of a single
XNX transmitter installation per power source�
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�
Figure 30. Multiple Transmitters Powered by a Single Power Supply
Advantages:
• Maximum distance between power source and
transmitters
31
Class 2 Class 2
Power Supply Power Supply
Class 2
Power Supply