Sensor systems 2 AS-Interface

AS-Interface - Introduction
10
Master
Master
Master
Data Protection
The interference resistance of data transmission is an important parameter
for the networking of sensors and actuators in an industrial environment.
Due to the special type of coding (Manchester Code APM, Alternating Pulse
Modulation) and the continual monitoring of signal quality, AS-Interface
achieves such a high level of data protection, that the system is also suitable
for safety applications.
This is not affected by the absence of screening on the transfer cable. Tests
on a welding robot and a galvanising plant showed that the AS-Interface
system was not affected by these levels of external interference. This is
possible due to the symmetrical signal transfer, which filters out interference.
Network hierarchy and topology
AS-Interface is designed for the lowest level of the automation hierarchy
and offers a simple, safe and fast transfer at an optimum cost/effectiveness
ratio. The system topology can take the form of a line, star, tree, or ring
structure. For information which is not time-critical and for the achievement
of longer transfer paths, AS-Interface can be connected via gateways to
higher level systems such as PROFIBUS, InterBus, EtherNet TCP/IP, DeviceNet,
Modbus, Modbus+, CCLink, CANopen, etc. AS-Interface masters
with serial RS 232 interfaces and integrated PLC functionality provide a distributed
stand-alone solution. In this way the control system is unloaded
and, in addition, cycle times of, for example, 2 ms are achieveable when the
AS-Interface network is not fully populated. This solution is directly aligned
with the trend towards the decentralised construction of control units. The
advantages are:
simpler and faster expansion possibilities and also the commissioning of
sub-domains,
shorter cable connections and less data communication on the higherlevel
field bus,
reduction of down time due to the autonomously operating sub-domains
and
shorter and clearer programs.
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group Tel.: Germany +49 621 776-0 USA +1 330 4253555 Singapore +65 67799091 Internet http://www.pepperl-fuchs.com
Issue date 2004-11-19 - Catalogue AS-Interface 2004/2005