Technical data

AS-Interface (AS-i)

1-10

SIMATIC NET AS-Interface – Introduction and Basic Information

C79000-G8976-C089/03

space of approximately 2 cm

S Increased functionality, more uses for the customer

Direct integration allows devices to be equipped with a wide range of functions.

Four data and four parameter lines are available. The resulting “intelligent”

actuators/sensors increase the possibilities, for example, monitoring, parameter

assignment, wear or pollution checks etc.

S Additional power supply for higher power requirements

An external source of power can be provided for slaves with a higher power

requirement (see /1/).

System Limits

S Cycle time

– max. 5 ms with standard AS-i slaves

– max. 10 ms with AS-i slaves using the extended addressing mode

AS-i uses constant message lengths. Complicated procedures for controlling

transmission and identifying message lengths or data formats are not

required. This makes it possible for a master to poll all connected standard

slaves within a maximum of 5 ms and to update the data both on the master

and slave.

If only one AS-i slave using the extended addressing mode is located at an

address, this slave is polled at least every 5 ms. If two extended slaves (A

and B slave) share an address, the maximum polling cycle is 10 ms. (B

slaves can only be connected to extended masters.)

S Number of connectable AS-i slaves

– Maximum of 31 standard slaves

– Maximum of 62 slaves with the extended addressing mode

AS-i slaves are the input and output channels of AS-i system. They are only

active when called by the AS-i master. They trigger actions or transmit

reactions to the master when commanded.

Each AS-i slave is identified by its own address (1 to 31). A maximum of 62

slaves using the extended addressing mode can be connected to an

extended master. Pairs of slaves using the extended addressing mode

occupy one address; in other words, the addresses 1 to 31 can be assigned

to two extended slaves.

If standard slaves are connected to an extended master, these occupy a

complete address; in other words, a maximum of up to 31 standard slaves

can be connected to an extended master.

S Number of inputs/outputs

– A maximum of 248 binary inputs and outputs with standard modules

– A maximum of 248 inputs/186 outputs with modules using the

extended addressing mode

Each standard AS-i slave can receive 4 bits of data and send 4 bits of data.