Cooper Bussmann Wireless Ethernet & Device Server BU-945U-E 802.11 DSSS User Manual
CHAPTER 2 - INSTALLATION
2.1 General
The BU-945U-E modules are housed in a rugged aluminum case, suitable for DIN-rail mounting. Terminals will accept wires up to 2.5 mm2 (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 BU-945U-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 BU-945U-E Module as a repeater.
The BU-945U-E Installation Guide provides an installation drawing appropriate to most applications. Further information is detailed below.
Each BU-945U-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.
2.2 Antenna Installation
The BU-945U-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 BU-945U-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 BU-945U-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 section 6 of this manual.
Where it is not possible to achieve reliable communications between two BU-945U-E modules, then a third BU-945U-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 BU-945U-E unit has two antenna connections at the top of the module, allowing two antennas to be fitted to the unit. The left connector (looking at the front) labeled “RX” is connected only to the internal wireless receiver. The right connector labeled TX/RX is connected to both the transmitter and receiver.
Note: Each antenna port has the option to enable /disable the Receive and Transmit functionality by selecting Receive and Transmit Diversity on the radio page. When only one antenna is used, it must be connected to the TX/RX connector.
