Siemens SIMATIC 277 IWLAN, Начало работы

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HMI Device Mobile Panel 277 IWLAN
Getting Started, 04/2008, A5E01004533-01
4.1 Interference factors in a wireless network
Even if all the security functions on the access point have been correctly
configured, special factors may disrupt the data exchange with WLAN.
Therefore, allow for factors which may cause interference in planning your
wireless network.
Sources of general physical interference
The following interference factors may affect a WLAN:
• Collision with other access points
The access points operate in simplex mode. Therefore, only one station can
transmit in a channel at any one time. Neighboring access points on the same
channel may have a disruptive effect on one another.
• Third-part wireless networks
If other wireless systems are used at 2.4 GHz in the same area as the WLAN,
e.g. Bluetooth, motion detectors or a microwave oven, this may lead to con-
siderable interference in data transmission.
• Interior
The characteristics of electromagnetic waves vary depending on the nature of
the surface of the objects they strike:
• Non-conducting objects absorb part of the waves, reflect a part and let a
part through.
• Electrically conductive objects reflect the waves almost completely.
• The waves are scattered when they strike edges.