Spectris Particle Measuring Systems IsoAir 310P, Operation Manual

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Page C-12 IsoAir 310P Aerosol Particle Sensor Operations Manual
Appendix C Wi-Fi Configuration Tips
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A laptop can be used to provide a rough map of wireless coverage in a plant. Connect
the laptop to the wireless sensor network and watch the signal strength bars on the
bottom right of the laptop as you perambulate through the sensor installation area.
•
The Wi-Fi bridge provides the average signal strength of the wireless signal. This is
on shown on the Wi-Fi bridge web server
Status screen.
•
Wireless signal strength drops by 6dBm for every doubling of distance between the
transmitter and receiver. An increase in distance of 1.4x will cause a reduction of
3dBm.
•
802.11b/g communications is designed to work reliably with low signal strengths. It
does this by reducing the communication speed when needed.
Table C-2 provides a
rough idea of signal strength and data rate for 802.11g.
Table C-2 Wireless Data Rate versus Signal Strength
Data Rate
(802.11 g)
Average Signal Strength
54Mb/s -69 dBm
48Mb/s -70 dBm
36Mb/s -74 dBm
24Mb/s -78 dBm
18Mb/s -81 dBm
12Mb/s -83 dBm
9Mb/s -85 dBm
6Mb/s -86 dBm
•
If the signal is weak, communications reliability may be improved by forcing the
router to use a lower data rate. This will prevent “hunting.”
•
A good safety factor is to allow at least 3 dB of signal margin.
•
Wi-Fi signals do not penetrate steel and concrete walls.