905U-G Wireless Gateway
User Manual
Page 17
©September 2004
This type of network reduces the amount of radio traffic and is suitable for systems with a
large number of I/O modules. The system is divided into local sub-networks, each with a
905G unit. The 905U modules transmit their I/O vlaues to the 905G. The 905G then
transfers these values to the “central” 905G using a block transfer which is very efficient
compared to a lot of individual I/O transmissions.
The data concentrator network is different than using the 905G as a repeater. A repeater re-
transmits each message in the same format. A data concentrator collects the I/O values as a
block, and transmits the complete block in one transmission.
1.3.4
905G Repeaters
Any 905U module can repeat a normal radio message, however only 905G modules can
repeat a block message. 905G units connected to a host device can also act as a repeater for
other modules.
Where a 905G is being used without a host device as a repeater or data-concentrator, it can
be configured as “Repeater-only”. This allows the RS232/485 port to be used for on-line
diagnostics. If the unit is a 905U-G-MD1, the “Repeater-only” configuration also allows
this module to connect to 105S serial I/O modules.
TO HOST
DEVICE
NETWORK OF
905U I/O UNITS
905U-G
905U-G
NETWORK OF
905U I/O UNITS
905U-G