Options - AS-i Bus System
Series 79 Pneumatic Actuator and Type-57 Butterfly Valve
Actuator-Sensor Interface (AS-i) offers many of the benefits of more complex and costly bus systems, but does it at a substantially lower cost, and with greater simplicity. The AS-i is ideally suited for controlling valves, actuators and many other field devices in your processing application.
This interface can be used for stand-alone process control, or it can be used together with a higher-level bus control system. AS-interface does not compete with higher-level bus systems; it should be seen as a complimentary system that offers low cost, reliable device control for binary and analog devices. Reliability, simplicity and interoperability make AS-interface a cost effective connection/control solution, particularly where low installation costs are imperative.
A single pair of wires, which handles power and communications, is used to control the network by means of "chaining" the actuators with the PLC. Each actuator (or device) will then have its own unique address within the system, and only that device with the proper address, will respond to system commands.
AS-i is best known for its yellow flat cable, which is pierced by insulation displacement connectors so that the expense of tees and complex connectors is avoided. Devices are simply clamped onto the cable.