Bihl+Wiedemann (Germany) has released the BWU2804 safety controller with an integrated CANopen interface: the AS-i 3.0 CANopen gateway complies with CiA 301.
THE DEVICE IS THE COMBINATION OF AN ALREADY EXISTING MEMBER of the company’s portfolio along with some additional features: the controller is a Safety Basic Monitor with integrated fieldbus interface. It does not have the same appearance: its core is no longer encased in 22,5 mm plastic housing, but rather a mechanically rugged stainless steel enclosure with a display for commissioning and diagnostics. The CANopen interface is integrated directly into the safety unit. This means the controller can call up all safety information without any additional software parameter settings. The status of all safety devices is available in real-time as a standard signal. Now the controller is able for example to bring the machine into its desired state before the safety unit shuts off the power after Stop 1. The safety monitor offers a start delay below 10 ms and a maximum turn-off time below 40 ms.
Integrating the fieldbus interface into the safety unit offers advantages when it comes to diagnostics. Among other things, the directly readable shut-off history saves time, since the search for the trigger of a shutdown is now a thing of the past even for small systems. The corresponding information is also available through a web server for remote maintenance. It is also possible to view the status of the system on the device’s own display. The CANopen interface offers a bit-rate of 10 kbit/s to Mbit/s, extended and minimum boot up, and life guarding according to CiA 301. The unit has an operating temperature of 0 °C to 55 °C, IP20, and a maximum tolerable shock and vibration stress according to EN 61131-2. It weighs 800 g and measures 100 mm x 120 mm x 106 mm.
The range of functions for the safety controller has increased along with the number of diagnostic options. Twelve configurable terminals allow the user to access up to six (2-channel) outputs, six (2-channel) inputs, or standard inputs. With the Asimon 3 G2 software, it is possible to redefine safety outputs as safety inputs if needed. The integrated AS-i master is expandable up to 31 safe or 248 standard I/Os (or any combination) and it offers diagnostic capabilities such as duplicate address detection, integrated earth fault and EMC monitor. Different diagnostic features are spontaneous diagnostics using the display and detailed diagnostics and history of each switching state in the display, over fieldbus or software. All states are accessible over the fieldbus without additional efforts.
Stoppage is doubtless the safest condition for a production system – but it is also the most expensive. The better the safety and standard systems work together within a machine, the quicker any faltering components can be tracked down. The trend towards automated safety has rather quickly become a mega-trend. According to the 2009 study “Safety in Machine Building” around half of all companies were already using safety based communication technology in the field. The key motivations for this shift were simpler access to data and – perhaps most important – better diagnostics. In the opinion of market insiders this development is gaining even more momentum. In part, of course, thanks to the new EC Machinery Directive, but mainly because fewer and fewer companies want and can afford longer downtimes, with the result that greater diagnostic capability is being demanded of the systems. Because this is also becoming more and more relevant for small and medium-sized systems, the company has developed a solution for those systems.
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