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The Actuator Sensor interface was originally developed by Siemens to provide a low-cost, efficient wiring & communication system for low-level industrial field devices. The protocol is currently owned & managed by the AS-Interface organization.

ASi uses a continuous, polarized two-wire cable that is chained between all the devices in a system. ASi devices connect to the wire with piercing "vampire" taps, which greatly simplifies the wiring process. The special, self-healing quality of the ASI cable allows for an IP67 rating, even after a device has been removed from the cable. The ASi cable also delivers power (24 VDC at 8 amperes) to the field devices.

The ASi physical layer operates at 167 kbits/second, and uses Manchester II encoding for reliable data transfer. The physical layer supports up to 100 meters of cable without repeaters, or up to 300 meters using two repeaters. The ASi link layer allows up to 31 devices to be chained together (up to 62 devices with some additional engineering). Because each ASi telegram only contains four bits of information, all 31 devices can be interrogated in 5 milliseconds, allowing for a fast scan of the low-level devices.

A variant of the ASi protocol, called "Safety at Work", allows for ASi devices to be used for Safety Shutdown Systems.

Over 60 vendors support the ASi fieldbus with everything from PLCs to E-stop switches and visual indicators. The AS-Interface organization requires conformance testing and certification for all devices.

What Can AB Tech Solution Do for Your ASi Product Development?
  • Develop a fully-compliant product for you
  • Add ASi capability to your existing product
  • Enhance the features and functionality of your product
  • Perform interoperability testing
  • Obtain AS-Interface organization certification for your products