Devices conforming to the AS interface (Actuator Sensor interface) set of open specifications are used to make up control systems based on a two-wire communication cable known as a bus. Up to 31 actuators and sensors (“slaves”) can be connected to the AS interface bus, and can be controlled or monitored by means of a digital signal sent via the bus to and from a “master” device (which can be a computer or a PLC).
The AS interface 2.1 specification allows 31 slave devices to be powered by a DC voltage fed into the same two-cable wire used as the communication bus, with allowed power consumption adequate to drive the slave plus a standard pneumatic solenoid valve. An AS interface bus can be used as the final field link in a more complex hierarchy of devices making up a large plant-wide control system. Actuators and sensors must often be installed in unprotected environments where conditions can be demanding; the AS interface bus is ideal for using as the link between these field devices and the “indoor” equipment making up the upper part of the control system. AS interface is well suited to on/off control and monitoring, and is a good choice when a simple economical, reliable and robust solution is required to control and monitor a series of actuators and sensors in a process control or machine application. Kinetrol’s AS interface Universal Limit Switch Box is designed to meet all of these requirements.
