Actuator Sensor Interface (AS-Interface or ASi) is an industrial networking solution (physical layer, data access method and protocol) used in PLC, DCS and PC-based automation systems. It is designed for connecting simple field I/O devices (e.g. binary ON/OFF devices such as actuators, sensors, rotary encoders, analog inputs and outputs, push buttons, and valve position sensors) in discrete manufacturing and process applications using a single two-conductor cable.
AS-Interface is an 'open' technology supported by a multitude of automation equipment vendors. The AS-Interface has been an international standard according to IEC 62026-2 since 1999.
AS-Interface is a networking alternative to the hard wiring of field devices. It can be used as a partner network for higher level fieldbus networks such as Profibus, DeviceNet, Interbus and Industrial Ethernet, for whom it offers a low-cost remote I/O solution. It is used in automation applications, including conveyor control, packaging machines, process control valves, bottling plants, electrical distribution systems, airport baggage carousels, elevators, bottling lines and food production lines. AS-Interface provides a basis for Functional Safety in machinery safety/emergency stop applications. Safety devices communicating over AS-Interface follow all the normal AS-Interface data rules. The AS-Interface specification is managed by AS-International, a member funded non-profit organization located in Gelnhausen/Germany. Several international subsidiaries exist around the world.