The AS-i Safety at Work Profile (sometimes called ASi-safe) was developed by a Consortium of Safety-related vendors for use in Functional Safety applications. It enables Safety devices such as Emergency Stop buttons, Light Barriers and Interlocks to run on the same cable as a standard AS-i system, offering major savings in design, engineering and commissioning. The Safety Devices operate within the same cyclic pattern as the standard AS-i devices. A special Safety Monitor resides on the bus to listen only to the Safety devices. It recognises when a Safety-related event occurs e.g. a Stop Button is pressed and initiates a shut down. High integrity communications ensure that the process is entirely fail-safe. Safety performance up to SIL3 can be achieved. Many, many AS-i Safety systems are in operation today, in applications ranging from conveyor-based assembly lines to advanced robotics and even airport carousels.
AS-i Safety systems are configured using special software that outputs documentation to help validate the chosen safety strategy. The latest version of the Safety Monitor offers considerable flexibility in terms of zoning and combination switching of fail safe devices. Because of its modular nature, AS-i Safe can be used as a safety system independently or on the same AS-i circuit as the control and monitoring system.
IMPORTANT NOTE: The above is intended for guidance only and is not a recommendation to use AS-i Safety at Work components or systems in specific applications. It does not obviate current legal or moral responsibilities involved in the design and implementation of Functional Safety systems. Of critical importance is the COMPETENCE of everyone involved in Functional Safety applications, both vendors and users. If you are not ‘competent’, you must work with someone who is ‘competent’ if you plan to utilise Functional Safety.
You may find the following paper prepared by Peter Cheetham of Newlyme Controls helpful. It contains, not just an overview of the use of AS-i within safety but addresses the challenges faced by designers, operators and safety officers in today’s regulatory environment. Safety_at_Work_-_Next_Generation.pdf