RF500 Wireless Monitoring System Overview
Gateway – Introduction
The RF500 Gateway is an embedded microprocessor device containing a radio module for RF
communications to the measuring transmitters. The radio module uses a licence free band in
the 2.4GHz spectrum. Comark Limited use proprietary protocols over a standard IEEE
802.15.4 link. These protocols achieve reliable communication between the transmitters and
the Gateway via self-healing mesh radio networks.
Data from measurements taken by the transmitters is stored on the RF500 Gateway in
contrast to other systems which store their data on a PC using special software. For operating
the RF500 system the only software required is a Web Browser such as Internet Explorer or
Firefox. There is no requirement to install software on each users PC.
The Gateway contains sufficient data storage capacity for up to 10 years which can be
automatically backed up to a PC using the optional software RF500 Backup Server or by
manual request to generate and download a backup file via your web browser.
Connection to the Gateway is via Network (Ethernet) connection or remotely via analogue
modem. For modem access a dedicated Analogue phone line must be provided.
An external power adaptor provides the mains power for the Gateway. An internal Nickel-
Metal-Hydride (Ni-Mh) rechargeable battery is included, this provides normal operation of the
Gateway during power failure until the battery is exhausted, The Gateway then shuts down
until power is restored.
Two relay connectors are provided for external alarms, Autodiallers/Klaxons etc. All other
connections to the Gateway are disabled. See Figure 3 – Left Hand Side View of Gateway for
further details.
Emails for alarms will be instigated directly from the Gateway. It is also possible to send a text
message alarm via email using a third party provider.
The Gateway can be either desk mounted or wall mounted. Wall mount keyhole slots are
provided on the case. The external long range Antenna has variable orientation to suit vertical
or horizontal mounting.
Three LEDs on the Gateway display current status of the system – Mains/Battery, Alarm
indication, and Fault indicators.
Overview of RF500 Mesh Networking
The RF500 Wireless Monitoring System uses the IEEE 802.15.4 radio transmission standard
to implement a radio mesh network.
A mesh network is comprised of the following devices:
• Gateway
• Mesh Transmitter
• Transmitter
On installation each transmitter is associated with a particular Gateway by serial number.
Messages are transferred between transmitters and the Gateway using two-way
communication with acknowledgement of successful message reception.
Transmitters which are physically close to their associated Gateway such as transmitter A in
Figure 7 below, will most likely transmit directly to it. Others such as transmitter B which are
further away rely on meshing transmitters to forward messages to and from the Gateway on
their behalf.
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