Sensor systems 2 AS-Interface

Issue date 2004-11-19 - Catalogue AS-Interface 2004/2005
K5
K20
G4
KF
PCI
AS-Interface - Introduction
1.3 Components in the AS-Interface system
Products from Pepperl+Fuchs are certified by independent AS-Interface
testing authorities. This ensures that the products satisfy the AS-Interface
specification and can be operated without problem in a system together with
other certificated AS-Interface products, including those from other manufacturers.
This is indicated by the shadowed logo on the data sheets.
Masters and Gateways
The core of the AS-Interface system is the Master (serial connection via
RS 232) and the Gateway (master with an interface to the commonly used
field buses). Earlier programming by PC or PLC can continue to be utilised,
for example, with an S7-400 with a standard I/O data range, since AS-Interface
behaves as an I/O card. The devices control and monitor the data exchange
with the modules and AS-Interface sensors/actuators on the Master-Slave
principle. However, as seen from the field bus, the gateway behaves
as a slave or station node, with typically more than 32 bytes of input/output
data and also with additional analogue channels and management
channels.
Master/Gateways are available in the form of plug-in cards for a PC, as control
cabinet devices and as field devices. The masters/gateways include a
diagnostic function with the following monitoring functions:
Configuration errors: Deviation between existing slaves and configured
addresses,
Peripheral faults: Loss of function of one or more slaves,
Communication faults: Incorrect transfer of several messages,
Detection and display of duplicate addressing and ground faults (on K20
series),
Safety diagnosis: Separate presentation of the safe slaves and display of
the diagnostic function of the monitor.
AS-Interface power packs (2 A to 8 A, with 30.5 V and data decoupling)
are used for the power supply. Repeaters and Power Extenders allow the
power supply to be decentralised and cable length to be extended to over
100 m. The repeater galvanically isolates the primary and secondary sides,
in order to provide a reduced probability of failure in the case of a short circuit.
A number of repeaters can be operated in a star formation, their
number being limited only by the input resistance at the AS-Interface. However,
it is only possible to operate a maximum of 2 repeaters in series. Together
with the repeater, an AS-Interface power supply is required for the
power supply of the other AS-Interface circuit.
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
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