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To determine which channel is currently in use for the WRS/RSX wireless link, use the STATUS RSX
command. See the Current Channel parameter (listed under RF Settings in the status report).
You can also manually select a permanent (non-changing) channel for use by the WRS/RSX pair using
the SET RSX command via the WRS HMI. If you manually select a channel, the WRS/RSX stays on the
selected channel until manually set to another channel (or if you rebind the WRS/RSX pair, upon which the
channel setting goes back to being made automatically by the WRS/RSX pair).
For more information on channels, see the Wireless Networks in Building Automation Systems White
Paper on iKnow.
Automatic Channel Changing
The automatic channel changing feature:
•
only occurs for an RSX that is bound to a WRS.
•
is limited to a maximum of 13 automatic channel changes per day (this is based on the number
of allowable EEPROM write cycles).
•
does not occur for a WRS/RSX communication link that is simply weak due to either distance
or obstructions between the RSX and WRS (since changing to another radio channel does not
improve wireless communication in this case).
•
uses the Avg Channel RSSI, MAC % Backoffs, and MAC % Acked parameter values (displayable
via the COMM RSX command using the WRS HMI) to determine whether to change to a new radio
channel. Once interference starts, channel changing occurs between 10–60 minutes later. Since
typical WRS/RSX communication occurs only every 1–5 minutes, 10–60 minutes need to elapse
before enough wireless metrics are gathered to calculate whether a channel change is warranted.
•
uses the following channel order for automatic channel changing by the RSX: 15, 10, 5, 14, 11,
9, 6, 4, 1, 13, 12, 8, 7, 3, 2. Thus, if channel 15 is determined to be bad, the RSX switches to
channel 10, etc.
Revision Date: July 10, 2008
Siemens Building Technologies, Inc.
Table 13. Channel and Frequency.
Channel
12
13
14
15
16
Wireless Room Sensor Solution
(continued)
Frequency (MHz)
2460
2465
2470
2475
2480
41
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