Specifications
AS-Interface
Introduction
AS-Interface specification
Specification 2.0, 2.1 and 3.0
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Overview
Scope of the AS-Interface specification
Basic data of AS-Interface Specification 2.0
• AS-Interface Specification 2.0 describes a fieldbus system
with an AS-i master and up to 31 AS-i slaves.
• Each AS-i slave has up to 4 digital inputs and 4 digital outputs.
• With full expansion, the complete transmission of all input/
output data requires max. 5 ms cycle time.
Expansions of AS-Interface Specification 2.1
AS-Interface Specification 2.1 enables the number of network
stations to be doubled from 31 to 62 as follows:
• The standard slaves continue to occupy one AS-i address
(1...31).
• Slaves with extended addressing divide an address into an A
address (1A...31A) and a B address (1B...31B). Up to 62 A/B
slaves can be connected accordingly to one AS-i network.
• Mixed operation of standard slaves and A/B slaves is possible
without difficulty. The AS-i master identifies automatically
which type of slave is connected. No special adjustments are
required of the user.
Another function of the AS-Interface Specification V2.1 is the
integrated analog value transmission function. Access to both
analog values and digital values is possible without the need for
any special function blocks.
Expansions of AS-Interface Specification 3.0
• AS-Interface Specification 3.0 enables the connection of a
nearly 1000 digital inputs/outputs (profile S-7.A.A: 8DI/8DO as
A/B slave).
• New profiles have also enabled the option of expanded
addressing for analog slaves.
• Acceleration of analog value transmission through
"Fast Analog Profile".
• Variable use of analog modules: Optional parameterization of
resolution (12/14 bit) and 1 and 2-channel capability.
• Asynchronous serial protocol 100 baud or 50 baud,
bidirectional.
AS-Interface masters
To be able to operate A/B slaves on an AS-Interface network you
must use master modules that meet the minimum requirements
of Specification 2.1.
The AS-i masters for S7-300 / ET 200M and all DP/AS-i links and
IE/AS-i links comply with AS-Interface Specification 3.0 and sup-
port all new and previous slaves.
The AS-Interface specification relevant for the respective slave
is noted in the Selection and ordering data.
The exact slave profile can be found in the system manual for
AS-Interface.
Communication cycle
Each address is queried in max. 5 ms cycle time. If two A/B
slaves are operated on one basic address (e.g. 12A and 12B), a
maximum 10 ms will be required for updating the data of both
slaves.
Whether an AS-Interface slave is a standard slave or an A/B
slave can be seen in the section "Selection and ordering data" or
the system manual for AS-Interface.
All slave types can be mixed and used on a single AS-Interface
network.
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More information
AS-Interface system manual
More information is available in the AS-Interface system manual.
The German-language AS-Interface System Manual can be
downloaded free from the Internet at:
http://support.automation.siemens.com/WW/view/de/26250840
The English-language AS-Interface System Manual can be
downloaded free from the Internet at:
http://support.automation.siemens.com/WW/view/en/26250840
A print version of the AS-Interface System Manual is also avail-
able in both English and German, see page 146.
Internet
You can find more information on the Internet at:
http://support.automation.siemens.com/WW/view/en/10805888/130000
AS-Interface specification Maximum number of slaves Number of digital inputs Number of digital outputs
Digital Analog ASIsafe DI DO
Version 2.0
31 31 31 31 × 4 = 124 31 × 4 = 124
Version 2.1
62 31 31 62 × 4 = 248 62 × 3 = 186
Version 3.0
62 62 31 62 × 8 = 496 62 × 8 = 496
AS-Interface
specification
Available masters
Version 2.1
CP 243-2 (S7-200)
Version 3.0
CP 343-2, 343-2P (S7-300 / ET 200M),
DP/AS-i Link Advanced, DP/AS-i F-Link,
DP/AS-Interface Link 20E, IE/AS-i Link PN IO
AS-Interface
specification
Maximum cycle time (digital signals)
Version 2.0
5 ms
Version 2.1
5 ms with 31 slaves
10 ms with 62 slaves
Version 3.0
5 ms with 31 slaves
10 ms with 62 slaves, supplementary,
up to 20 ms with A/B slaves using 4DI/4DO,
up to 40 ms with A/B slaves using 8DI/8DO.
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