Page 868 - Sensors and Systems - North American Catalog
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AS-Interface
Introduction
Introduction
What is AS‑Interface?
Actuator Sensor Interface (AS-Interface) is a simple-
to-install, two-wire network that has become the
standard discrete I/O system used in automation
industries throughout the world to connect devices
such as sensors, analog and safety data, encoders,
light curtains, and e-stops. Specifically designed
for simplicity, flexibility, and reliability, it has extremely fast mounting,
startup and update times, and replaces traditional wiring architectures. It
has a totally open topology—there are no limitations on how to route or
split network runs. A single unshielded cable with no termination and a
high degree of noise resistance carries data and power. In addition, AS-
Interface is an open, vendor-independent system with support for all the
major PLC brands and compatible with any of the major industrial upper-
level networks. AS-Interface is standardized in EN50295 and IEC 62026-2.
The Main Benefits of AS‑Interface
• Free choice of topology
• Works with all field busses
• Simple installation with piercing connection technology
• Reverse-polarity protected flat cable
• Decentralized solutions
• Transmission of safe input and output signals
• Simple extension, flexible adaptation
• Automatic addressing after device exchanges
• Monitoring of sensor failures, cable breaks, and short-circuits
• Interference-resistant data transfer on unshielded flat cable
• LED/LCD diagnostics on gateways/scanner cards
AS-Interface Topology
• The network topology is completely open
• Installation layout fits each application
• No termination required
• Power supply and modules can be placed anywhere in the segment
Designing a Network
• An AS-Interface network consists of a collection of segments.
• Each segment can have a cumulative cable length of 100 meters
• Repeaters extend the length by 100 meters. Up to two repeaters,
which galvanically isolate the segments, may be connected in series
• Maximum length of a linear AS-Interface network is 500 m
• Regardless of cable length and number of repeaters, a maximum of
62 I/O modules can be placed on AS-Interface
How Does AS-Interface Operate?
Up to 62 I/O modules connect to the network and each module can
connect a number of I/O points. The scanner/gateway calls each module
sequentially and awaits each response. In each cycle, 4 bits of information
are transferred from the scanner/gateway unit to each module, and 4 bits
are returned.
Wiring - Round Cable and Flat Cable Connections
Although a standard two-wire round cable can be used, the preferred way
to install AS-Interface is via the famous yellow flat cable. It provides an
efficient installation method and, due to the mechanical keying, guarantees
correct polarity. Also, the yellow cable ensures that the network operates at
peak electrical performance, regardless of the network length (up to 100
meters per segment) and network topology.
In addition to using the yellow AS-Interface network cable, a black,
mechanically keyed flat cable supplies auxiliary power. The auxiliary power
is used to power output devices, such as lights, valves, or actuators. Both
cables are offered in standard and oil-resistant versions.
I/O
Module
I/O
Module
I/O
Module
I/O
Module
I/O
Module
I/O
Module
Repeater
Repeater
AS-Interface
Power Supply
AS-Interface
Scanner/Gateway
AS-Interface
Power Supply
AS-Interface
Power Supply
100 m total cable length
30 m
10 m
10 m 30 m
10 m
30 m
30 m
20 m
30 m
30 m
30 m
10 m
10 m
10 m
10 m
100 m total cable length
100 m total cable length
Scanner
I/O Modules
AS-i Power Supply
A normal AS-Interface network segment
has a maximum cable length of 100 m
and no termination. Because of the
design of the network, a “tree topology”
can be used to run cable anywhere
required by the application.
AS-Interface segments can have a cumulative cable length of
100 meters. This means that all network cable added together
in a segment must equal less than 100 m. If larger networks
are needed, a repeater can be used to extend the length by
100 meters. Because repeaters isolate the connected network
segments, an AS-Interface power supply must be located in
each. When designing networks with repeaters, it is important to
note that no signal from a scanner/gateway to a node can travel
through more than two repeaters.
AS-Interface
AS-Interface,
Master/Gateways
7 7
.1
AS-Interface,
Power Supplies, Power Extender and Repeater
7
.2
AS-Interface,
Safety at Work
7
.3
AS-Interface,
Modules
7
.4
AS-Interface,
Indicating/Operating
7
.5
AS-Interface,
Accessories
7
.6
