In recent years, safety technology has become increasingly important in machine and system production. This is because complex automation solutions require flexible and cost-effective safety concepts, which offer the same advantages that users have come to appreciate in non-safe areas. This means that considerable savings can be made, e.g., in terms of both cost and time, by changing from parallel to serial wiring.

From the user's point of view, however, various requirements must be taken into consideration. Firstly, safe and non-safe signals must be separated in order to simplify the programming, operation, and acceptance of safety applications. Secondly, all components used should be operated on a fieldbus, as a standardized installation concept and standard operation make planning operation, startup, and maintenance easier. These basic requirements form the basis of the INTERBUS safety concept.

Method of Operation
With a transmission speed of 500 kbaud or 2 Mbaud, extensive diagnostic features, and easy operation, INTERBUS, which is certified according to IEC 61158, forms the basis of the safety bus system. As the INTERBUS master, the controller board uses an integrated safe control system. In addition, safe components have been developed based on standard IP67 and standard IP20 modules. The Safety profile has been integrated into the INTERBUS protocol for the transmission of safe data and parameters. Safety components and standard components can thus be operated via one bus cable. The INTERBUS controller board with integrated safe controller is the basic unit in the system. It processes all safety-related inputs and confirms them to the standard control system by setting an output or resets the output. This method of operation is similar to contact-based safety technology and is referred to as an enabling unit. The enable is programmed with pre-approved blocks such as emergency stop, two-hand control or electrosensitive protective equipment in "SafetyProg" Windows software, which is compatible with IEC 61131. The amount of programming required is reduced considerably through the use of blocks and the enable principle.

The safe input and output components form the interface to the connected I/Os. They control, for example, contactors or valves and read the input status of the connected safety sensors, including intelligent sensors. The user uses the parameterization function to select the settings for the I/O components such as clock selection, sensor type, and signal type. This means that numerous safe I/O devices are available that are already used by the user.The INTERBUS Safety system meets safety functions up to Cat. 4 according to EN 954 and SIL 3 according to IEC 61508. Depending on the application, the user can choose to use either a "one-cable solution with integrated safety technology" or a "two-cable solution", where one bus cable is used for standard signals and the other for safety signals. It is important to note that all the bus properties are still available and that there are no additional requirements for a "two-bus solution".

User Advantages

• Very short response times
• Optimum integration, i.e., safe and non-safe devices can be used in the same network
• Easy operation from planning to maintenance
• User-friendly and precise diagnostics with prophylaxis properties
• High level of system availability
• Robust system response to external influences
• Use of existing I/O components
• Safety buses can be retrofitted without any problems
• Highest level of safety up to SIL 3 according to IEC 61508 and Cat. 4 according to EN954
• Comprehensive project and service support