ASi Safety at Work.
Efficiently meeting safety requirements.
Safety requirements for a machine or a plant are often controlled by guidelines. But with or without guidelines - safety implementations are first and foremost rational. Even if a safety installation is never used during its lifetime, one single case where the health or maybe even the life of a person is saved, justifies its usage.
However, since safety installations do not have a direct influence on the productivity of a machine or a plant, actually rather lead to productivity loss, the designer is determined to find the most efficient safety solution possible. AS-Interface is highly supportive in this endeavor.
Safety and Standard I/O on a single network – All the advantages of AS-Interface are utilized!
Again, we have to recall the following: AS-Interface is the easy and economic wiring system for the lower level of industrial communications. An AS-Interface network consists of a control unit, the so-called master, and the associated sensor and actuator components, i.e. the slaves.
The great advantage of the AS-Interface solution is that even safety solutions can be incorporated into the AS-Interface network!
Safety components can easily be incorporated into an AS-Interface network via AS-Interface Safety at Work. In this case, safety and standard components are working in parallel using the same cable. The safety solution can benefit from all advantages of the AS-Interface network:
elimination of conventional wiring
reduction of wiring and installation costs
a safety PLC is not necessary
high system flexibility through easy and fast expandability of existing systems, upgrades are easy to perform
integration of safety signals into the system diagnostics
simple system design through standardized AS-Interface technology
In addition to the fundamental advantages of AS-Interface, the safety specific benefits also need to be considered:
combination of Safety at Work and non-safe standard AS-Interface devices on one network
Safe and non-safe data on one bus
grouping of safe signals is possible
certified up to performance level (PL) e according to EN ISO 13849, with nearly effortless determination of the total performance level of
the safety function by adding subsystems, even when multiple devices are connected in series. Recognized by TÜV and BIA.
Safety at Work is an easy add-on
monitor operates as multi-functional safety relay
diagnostics of the safety signals via direct connection to the control system
The AS-Interface master treats the safety slaves like any other slaves and connects them to the network. The data transmission protocol and the cables of the AS-Interface system are set up in a way to also allow the transmission of safety relevant messages.
The required safety is achieved by data exchange between a safe slave and a special component, the safety monitor. This transmission uses a special safety protocol. In case of emergency, the safety monitor or the safe outputs switch off the relevant system sections within a defined timeframe.
Standard and safety components on a common network. The safety monitor controls the safety slaves.
Safety monitor and safe outputs.
The safety monitor is used to monitor the safety components of an AS-Interface system. The safety monitor has one or two redundant release circuits used to safely deactivate potentially harmful operations. Several safety monitors can be employed when setting up output groups. The monitor address can be parameterized for extended diagnostics. Safe outputs monitor a safe input on the safety monitor. Safe outputs are switched-off by the safety monitor.
The safety monitor provides multiple functions that are easily parameterized, such as:
stop categories 0 and 1
Easily fulfilling the requirements of EN ISO 13849.
AS-Interface safety solutions are certified up to Performance Level e according to EN ISO 13849. Determining the total performance level PL is as easy as cake when using AS-Interface: one simply adds the sub systems, even when multiple devices are connected in series.By using a graphical editor with easy-to-read multifunction technology, AS-Interface safely, fast, and easily displays logical connections between safety components. Using the intuitive drag&drop interface, function blocks are connect, timer operations are defined, and start-up conditions specified. Consequently, by using AS-Interface Safety at Work, system expansions such as the connection of additional field or enclosure devices and their inclusion in the safety configuration are performed quickly. Just connect the safe device to the nearest yellow AS-Interface cable, and the device is ready to become part of the release circuit.
Each safe input can be clearly identified by its unique 8*4 bit code table. With the "teach in" function, the safety monitor reads the code table from each safe slave, and then monitors them continuously during operation. During operation, the expected and the actually received code tables are permanently compared. The safety monitor or the safe output, respectively, switch off the system if the expected code deviates from the actually code received, i.e. when:
- a stop was requested (0000),
- the communication is interrupted,,
- the transmitted sequences are wrong,
- the safe slave is destroyed, or
- missing or delayed slave responses were detected.
Safe transmission is guaranteed through the use of dynamic code tables. The safe slave sends the code table that will then be compared to a target table stored in the safety monitor or the safe output. If discrepancies or errors occur, the monitor initiates the shut-off sequence.
Grouping of safety components on one network is performed by using multiple channels, i.e. safety monitors that monitor the elements of the group.
ASIMON Demo der Konfigurationssoftware für den Sicherheitsmonitor
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