905U-G Wireless Gateway
User Manual
Page 53
©September 2004
To configure this special mapping, select the “New Don’t Send in Comms Fail Mapping”
box. You will be asked to select which remote module this function applies to. You can
enter more than one of these mappings if there are more than one modules.
4.3.4
Startup Polls
You can enter start up polls for remote modules by using the “New Poll Mapping” box. This
function is the same as for the 905U I/O modules. A start-up poll is a special message sent
when the 905G starts up. When the remote module receives a start-up poll, it will
immediately respond with update messages for all its inputs that are mapped to the 905G.
This allows the 905G to have correct values on start-up.
4.3.5
Polls to Remote Modules
It is possible for a 905G to send a poll to a remote module at other times apart from start-up.
A poll can be sent under the following events:
•
based on a configurable time period
•
based on real time clock
•
on-demand by the host device.
For information on this configuration, refer to the next section on “Block Mappings”.
4.4
Mappings from 905G to other 905G Modules
Individual links between 905G modules can be configured under the “Mappings” selection as
described in the previous section. For example, if you want to transfer I/O Reg 144 in
905G#2 to I/O Reg 286 in 905G#3, you can enter the following mapping:
Whenever I/O Reg 144 changed by the sensitivity amount, 905G#2 would send a message to
905G#3 to write the value in I/O Reg 286. The problem arises if there are a lot of these
mappings. Each radio message only relates to one register-register link. If you want to map
1000 registers from one 905G to another, then this could generate a lot of radio messages.
To get around this problem, it is possible to configure “block mappings”. With a block
mapping, multiple registers (a “block of registers”) can be transferred together in the one
radio message. This improves the efficiency of the radio communications.
