Westermo RM-455U-D - Manual (Page 7)

455U-D Radio Modem User Manual
Page 8 © May 2010
Chapter One INTRODUCTION
1.1 General
The 455U-D radio modem provides reliable radio modem operation with advanced
communication control and diagnostics functions. Radio modems transmit serial data over a
long distance via radio. The serial data is not changed - the output data is the same as the
input data. Although the 455U-D is intended to be simple in its application, it also provides
many sophisticated features. This manual should be read carefully to ensure that the modules
are configured and installed to give reliable performance.
Each 455U-D module will connect to a host device by RS232 or RS485 serial connection.
Examples of host devices are PLC’s, data loggers, intelligent transducers and computers. The
455U-D unit can receive data from the host device and transmit this data by radio to another
(or several) 455U-D module. The other module will recreate the serial data and output it as
either a RS232 or RS485 serial signal. The 455U-D unit provides two-way communications -
each module can accept serial data and also output serial data.
The 455U-D module has two data ports (one RS232 and one RS485) and can connect to two
host devices independently. The 455U-D also has another RS232 port (via a RJ45 connector)
which can be used only for configuration or access to diagnostics information - the RS232
data port can also be used for configuration and diagnostics.
RS232 is an electrical standard format for a full duplex point-to-point serial connection.
RS485 is an electrical standard format for a half-duplex multidrop serial connection. Up
to 32 devices can communicate on a common RS485 serial bus.
Each 455U-D can simultaneously
connect to signals from both RS232
and RS485. In addition, RS232 data
from one host device can be
transmitted to a remote 455U-D unit
and output as RS485 data to another
host device.
The unit includes a fixed frequency
radio transceiver with overall
frequency range 360MHz to
512MHz, in seven radio bands, each 20MHz wide. The user can configure the radio
frequency within the 20MHz band (refer to Diagnostics section).
The 455U-D is available with a high power radio (0.5 – 5W) suitable for licensed narrow-
width channels (12.5, 20 or 25KHz). The unit is also available with a lower power radio (10
– 500mW) suitable for license-free narrow-width channels, in countries where these are
available.
The operating parameters of the 455U-D are configured from a PC using a Microsoft
Windows configuration package provided free with the module, or from a PC terminal using
Hayes commands.
RS232
RS232
RS485
RS485
MULTIPLE DEVICE CONNECTIVITY