User manual

905U-G Wireless Gateway User Manual
Page 15 ©September 2004
905U modules can transmit input
messages directly to outputs on other
905U module, as well as the 905G. The
same input can be transmitted to different
addresses by entering two "mapping"
configurations at the remote module.
Normal 905U Messages
I/O registers in a 905G can be configured
(mapped) to outputs at remote 905U
modules, or I/O registers in 905G
modules. The 905G will transmit an I/O message when a “change-of-state” occurs for that
I/O register . Registers have a configurable “sensitivity” value - this determines how much
the register value has to change to trigger a change message. A change-of-state occurs when
the register value has changed by more than the sensitivity value since the last transmission.
The 905G also transmits periodic update messages if there has been no change - if an I/O
register is mapped to a remote output or another 905G, then that register can be configured
with an update time.
905G modules can transmit to 905G modules as well as other 905G modules. There can be
multiple 905G and 905C modules in a network - as well as 905U I/O. Because the 905U
protocol is peer-to-peer, there are few constraints on communications between multiple 905U
modules.
Poll Messages
A 905G can also generate poll messages to remote 905U modules. These poll messages act in
the same way as a start-up poll - the remote module immediately responds with update
messages for any I/O mappings configured to the 905G.
Poll messages can be triggered by:
♦ time period, configurable 1 – 4096 sec (1.1 hour), or
♦ real time clock, or
♦ on demand by the host device, by writing to a “trigger register” in the 905G
1.3.2 905G to 905G Network
Different types of 905G modules can communicate - for example, a Modbus 905G can
communicate with an Ethernet 905G. I/O registers in one 905G can be transmitted to I/O
registers in another 905G. When the 905G is configured, “mappings” can be entered linking
I/O registers to registers in another 905G.
905U-G
905U-3
905U-1
105S-2
905U-K
905U-G
905U-3
905U-1
PLC
905U-C
PLC