AS Interface

What is an AS-Interface?

AS-Interface is short for Actuator Sensor Interface. The abbreviations AS-i and ASi are most widely used. AS-Interface is a fieldbus standard specialized in connecting actuators as well as sensors. IEC 62026-2 is the industry standard for AS-Interfaces.

How does the bus system AS-Interface work?

The ASI-Standard involves a master communicating with an Actuator-Sensor-Interface-Slaves in a cycle. Data and energy can be transmitted. Consumers with a high demand in energy have to be connected via a separate cable. The voltage is 24 V. The following types of topology are supported: tree, star, line and ring.

An ASi-Master can provide for up to 62 slaves. 2-core wires are used to connect all Actuator-Sensor-Interface-Slaves. Ali-Masters and slaves are communicating via simple telegrams which are sent 31 (62) times per cycle.

AS-Interface - Advantages and Disadvantages

The wiring effort to connect sensors and actuators can be minimized by using ASi instead of the conventional way of wiring them parallel. Wiring IO components is simplified by piercing technology. The set up times can be minimized. Via the ASI-cable safe and unsafe signals can be transmitted which in turn lowers the set up cost. Standardization simplifies programming on IO-Level. After installation ASi-Slaves can be adressed.

The focus is on simpler IO components which can be viewed as a disadvantage if you want to link intelligent actuators or sensors.