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Protection zone
The protection zone is the area in the plant in which one or more machines are operated in
fail-safe mode. The protection zone of the plant is demarcated by a security system and
organizational measures.
The protection zone is not an object that can be configured.
Security system and organizational measures
The security system consists of one or more technical protection devices for the protection
zone, e.g.:
● Mesh fence with access
● Light barrier
● Contact pressure mat
The security system can be controlled by a safety program, such as a program for robot
control conforming to a robotics directive.
1.12
Rapid roaming
The wireless range of an iWLAN system can be expanded through the use of multiple
access points. If an HMI device moves beyond the range of a SCALANCE W78x and into the
range of another SCALANCE W78x, the wireless connection remains intact (roaming).
Capabilities provided by iPCF
In the industrial environment, there are applications that require deterministic behavior for a
large number of participants and high data throughput in a cell. In addition, deterministic
behavior is required for cell cross-overs with handover times of less than 100 milliseconds.
The iPCF extension (Industrial Point Coordination Function) was developed to meet these
requirements.
iPCF ensures that all data traffic runs in coordinated fashion in a wireless cell, controlled by
the access point. It also optimizes the throughput with a high number of participants by
avoiding collisions. iPCF also facilitates very fast cell changes.
Special features provided by iPCF-MC
iPCF-MC was designed to enable free-moving participants to exploit the special advantages
provided by iPCF, which allows communication independent of an RCoax line or directional
antennas. With iPCF-MC, the client looks for potentially suitable access points even when it
is receiving iPCF queries from the access point and the existing connection to an access
point is functioning correctly. This makes it possible to switch to another access point very
quickly if it becomes necessary. Unlike iPCF, with iPCF-MC the handover times do not
depend on the number of radio channels in use.
Wireless Teach Pendant F IWLAN V2
Operating Instructions, 08/2010, A5E02453837-01
PRELIMINARY II
1.7.2010
Overview
1.12 Rapid roaming
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