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245U-E Wireless Ethernet Modem User Manual
Rev Version 2.24
Chapter 2 - INSTALLATION
2.0 General
The 245U-E modules are housed in a rugged aluminum case suitable for DIN-rail mounting. Terminals will
accept wires up to 2.5 mm
2
(12 gauge) in size. All connections to the module must be SELV (Safety Extra
Low Voltage). Normal 110-250 V mains supply must not be connected to any terminal of the 245U-E
module. See “2.2 Power Supply.”
Before installing a new system, it is preferable to bench test the complete system. Configuration problems
are easier to recognize when the system units are adjacent. Following installation, the most common
problem is poor communications caused by incorrectly installed antennas, radio interference on the same
channel, or the radio path being inadequate. If the radio path is a problem (for example, the path is too
long or obstructed), a higher performance antenna or a higher mounting point for the antenna may rectify
the problem. Alternatively, use an intermediate 245U-E module as a repeater.
The
245U-E Installation Guide provides an installation drawing appropriate to most applications. Further
information is provided below. Each 245U-E module should be effectively earthed via the “GND” terminal
on the back of the module. This is to ensure that the surge protection circuits inside are effective.
2.1 Antenna Installation
The 245U-E module will operate reliably over large distances. However, the achievable distances will vary
with the application, radio model, type and location of antennas, the degree of radio interference, and
obstructions (such as buildings or trees) to the radio path.
The maximum range achievable depends on the radio model, the regulated RF power permitted in your
country, and whether you use separate transmit and receive antennas. If using a 245U-E-G (2.4 GHz) with
a single antenna, 10 km (6 miles) can be achieved in USA, Canada, and Australia (4 W EIRP) and 2 km in
Europe (100 mW EIRP). If using a 245U-E-A (5 GHz) with a single antenna, 5 km (3 miles) can be achieved
in USA, Canada, and Australia (1 W EIRP) and 3 km in Europe (500 mW EIRP), but more care is needed in
selecting antennas and coax, and radio paths need to be complete line of site (no obstruction whatsoever).
To achieve the maximum transmission distance, the antennas should be raised above intermediate
obstructions so that the radio path is true line-of-sight. The modules will operate reliably with some
obstruction of the radio path, although the reliable distance will be reduced. Obstructions that are close to
either antenna will have more of a blocking affect than obstructions in the middle of the radio path. The
245U-E modules provide a diagnostic feature that displays the radio signal strength of transmissions (refer
to “Chapter 4 - DIAGNOSTICS”).
Line-of-sight paths are only necessary to obtain the maximum range. Obstructions will reduce the range,
but may not prevent a reliable path. A greater amount of obstruction can be tolerated for shorter distances.
For short distances, it is possible to mount the antennas inside buildings. An obstructed path requires
testing to determine if the path will be reliable. Refer to “4.7 Testing Radio Paths.”
Where it is not possible to achieve reliable communications between two 245U-E modules, a third 245U-E
module may be used to receive the message and re-transmit it. This module is referred to as a repeater.
This module may also have a host device connected to it.
The 245U-E unit has two antenna connections at the top of the module, allowing for two antennas to be
fitted to the module if necessary. (
Note:
Antenna Diversity not available with the 245U-E-A1 model)