Weidmuller WI-MOD-945-E: 900Mhz Wireless Ethernet & Device Server v2.16 - Manual (Page 13)

Weidmuller Wireless Ethernet Modem & Device Server WI-MOD-945-E User Manual
Page 13 www.weidmuller.com Rev 2.136
CHAPTER 2 - INSTALLATION
2.0 - General
The WI-MOD-945-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 110-250V mains supply
must not be connected to any terminal of the WI-MOD-945-E module. Refer to Section 2.3 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, or radio interference on the same channel, or the radio path being inadequate. If
the radio path is a problem (i.e. path too long, or obstructed), a higher performance antennas or a higher mounting point
for the antenna may rectify the problem. Alternately, use an intermediate WI-MOD-945-E Module as a repeater.
The WI-MOD-945-E Installation Guide provides an installation drawing appropriate to most applications. Further
information is detailed below.
Each WI-MOD-945-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 WI-MOD-945-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.
A WI-MOD-945-E (900MHz) with a single antenna, 6.2 miles can be achieved in USA, Canada (4W ERP) and 10km in
Australia, New Zealand (1W ERP).
To achieve the maximum transmission distance, the antennas should be raised above intermediate obstructions so 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 which are close to either antenna will have more of a blocking affect than
obstructions in the middle of the radio path.
The WI-MOD-945-E modules provide a diagnostic feature which displays the radio signal strength of transmissions (refer
Chapter 4 “Diagnostics”).
Line-of-sight paths are only necessary to obtain the maximum range. Obstructions will reduce the range, however may not
prevent a reliable path. A larger 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 the 4.7 -
“Testing Radio Paths” of this manual.
Where it is not possible to achieve reliable communications between two WI-MOD-945-E modules, then a third WI-MOD-
945-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 WI-MOD-945-E unit has two antenna connections at the top of the module, allowing for two antennas to be fitted to
the module if need be. By default the right connector labelled TX/RX is the main connection used to transmitter and
receiver. The left connector labelled
“RX” is not connected unless configured under the Advanced Radio Configuration in
Section 3.9 - . Each antenna port can be configured for TX only, RX only or Diversity (TX and RX). Selection can be made
by choosing one of the options from TX Antenna / RX Antenna on the Advanced Radio Configuration page.