Communication Via As-Interface - Siemens SIRIUS 3RA6 System Manual

Accessories
7.12 AS-i mounting module for 3RA61/3RA62 compact starter
7.12.3

Communication via AS-Interface

The actuator sensor interface (AS-Interface) is a modular networking system for sensors and
actuators at the lowest field level.
As far as the program in the control system is concerned, it makes no difference whether
parallel wiring is used or whether the AS-Interface is used. As a result, it is possible to switch
over to the AS-Interface even on existing systems, as you can continue to use any programs
that are already installed. The entire system can be operated without additional software.
You do not need to know about the internal workings of the AS-Interface.
Replacement for cable harness
If parallel wiring is used for the compact starter, a large amount of wiring will be required for
the purpose of transferring process signals to the control system. This means that each
compact starter has to be connected to the control system by means of its own separate line.
However, if the AS-Interface is used instead, this cable harness can be replaced by a single
two-wire line that is shared by all compact starter groups (up to a maximum of 62 compact
starters).
Data and power via one two-wire line
The master communicates with the nodes via the AS-Interface lines. As well as being used
for data exchange, this line also carries the supply voltage for the electronics and the check-
back signals of the compact starter. The voltage is fed into the AS-Interface line by a special
AS-Interface power supply unit with data decoupling circuit.
Replacement
Upon replacement of a compact starter, the plug-in connections of the data line and for the
power supply of the electronics can be removed without influencing the communication of
other devices in the AS-Interface network.
Auxiliary power
The AS-i mounting module requires an external additional supply (AUX Power) for the output
circuits that must comply with Protection Class I in accordance with VDE 0106 (PELV).
Maximum system configuration
For detailed installation and mounting guidelines, please refer to the manual entitled "AS-
Interface System" (article number: 3RK2703-3AB02-1AA1).
Up to 62 nodes (e.g. compact starters) can be connected to the AS-Interface line. This is
possible thanks to the use of A/B technology, whereby the maximum 31 addresses are split
into two completely separate sub-addresses (e.g. 1A and 1B).
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SIRIUS 3RA6 compact starter
System Manual, 09/2014, NEB560060102000/RS-AA/006