Wireless System Design Considerations; Construction Of Multiple Wireless Systems - Omron WT30 Operation Manual

Wireless System Design Considerations

Connecting to Error
Output
2-3

Wireless System Design Considerations

2-3-1

Construction of Multiple Wireless Systems

Setting Wireless Channels
1,2,3...
32
PNP Output
WT30
V
ERRP
Load
G
NPN Output
WT30
V
ERRN
Load
G
When constructing a system for using multiple Serial Master Stations, the fol-
lowing points must be considered. Consult your OMRON representative.
Frequencies that are not interfered with by radio waves must be selected for
the wireless channels. (Radio interference can be handled by retry processes
between the wireless networks, but will lengthen the system response time.)
The WT30 supports 67 wireless channels from which to select. As a rough
guide, however, a maximum of 10 wireless systems can be used in a single
area without radio interference on account of the following considerations.
1. Do not select neighboring wireless channels as they have a large amount
of interference.
2. Due to the fundamental nature of radio waves, if two or more waves with
different frequencies are output at exactly the same time, mutual interfer-
ence will occur between the different frequencies, and new waves will be
generated with frequencies at intervals equal to the intervals between the
output frequencies. (This phenomenon is called intermodulation.)
For example, if channels 5 and 9 are used, electromagnetic interference
will be generated with channels 1 and 13, as shown in the following dia-
gram. In this case, channels 2 and 14 can be used, but the frequency of
channel 51 is located between the frequencies for channels 1 and 2, and
the frequency of channel 63 is located between the frequencies for chan-
nels 13 and 14. Therefore, the channel with the frequency following chan-
nel 1 is channel 51. Channels 5, 9, 51, and 63 can be used without
interference. For details on frequencies, refer to Appendix F Frequency Ta-
ble on page 105.
Section 2-3