Page 9 of catalogue Bus, identification and control systems of ifm Electronic GmbH

Notes and explanations

Master Master as the central part The AS-i operation, i.e. the communication with the slaves is continuously monitored and controlled in the master. These management functions are directly carried out at the hardware level of the master without a higher level of input being required from the user via programming. At the same time the binary information of the actuators / Sensors is supplied to the higherlevel control system (plc, PC, NC) via an interface. The data from the system’s inputs and outputs are presented in exactly the same way from the AS-i system as it would be from standard I / O modules thus programming in the control system remains unchanged allowing existing programs to be further used. Here the practical conception of AS-i can be clearly seen. Single-master system AS-i allows exactly one master per system. This master polls all participants cyclically. Its location in the AS-i tree is unimportant because every participant has its individual address. This address is stored non-volatilely in an EEPROM in every slave. The single-master system ensures constant defined cycle times which depend on the number of the participants and are 5 to 10 ms with the maximum capacity of the system. Depending on the application there are different options for connecting the actuator-sensor interface to the higher-level control system (host): plc master Using the AS-i plc master card the controller CPU can directly access the AS-i periphery. The AS-i master and CPU normally communicate via the internal plc bus which is also used for the exchange of data by other interface connections, e.g. the input / output modules. This ensures a quick exchange of data and compatibility with existing plc programs. So the user can further use his existing Software. Gateway to higher systems AS-i is designed as actuator-sensor-interface for binary participants. Therefore, couplers (so-called gateways) to higher-level bus systems (e.g. Profibus-DP) specially designed for larger data volumes are available. On the one hand, the gateway consists of an AS-i master which establishes the connection to AS-i and on the other hand of a connection to the higher-level system to which the AS-i data are transferred. Concerning programming the AS-i master is treated like a participant of the higher-level bus. Examples of gateways are the controller e family. PC master The AS-i master card for the PC provides the full functionality of the PC (visualisation, process control, collection of data) in combination with the actuator-sensor-interface. The PC in its industrially compatible design and due to falling prices is increasingly used in automation technology as part of the machine control. Here the advantages of AS-i can be directly integrated into the system. The user can program in a high-level language by using the specific AS-i driver which ensures communication with the master card.

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Technical information and customer service

Accessories

Connection technology

AS-i sensors, Pneumatic and actuator solutions

At the Deutsche Shell AG in the plant Grasbrook over 2,000 valve actuators are networked via the AS-interface.

Safety at Work

I/O modules for field applications

I/O modules for Control cabinets

Power supplies and earth fault monitors

Controllers / Gateways, network extension

List of articles

General information