Increasing requirements and constantly expanding areas of responsibility in automation are resulting in ever more complex and branched networks. In the safety sector, it is therefore important to connect safe networks efficiently. For this purpose, Bihl+Wiedemann developed Safe Link a few years ago, a safe coupling via the Ethernet interface of its AS-i gateways with integrated safety monitor. This makes it easy to connect several safe AS-Interface networks with each other, even if they are integrated in applications with different fieldbuses. In this way, almost 2000 slaves can communicate directly with each other across all connected AS-i networks - regardless of the overall technological concept of the system. Direct access to the input and output data of all machines involved is guaranteed at all times.

Bihl+Wiedemann has now developed a solution that safely couples two safety protocols: the PI safety protocol Profisafe via Profinet and the safety protocol CIP Safety via Ethernet/IP from ODVA, so that users outside of AS-i can also benefit from the Safe-Link technology. The solution consists of two AS-i 3.0 gateways with an integrated safety monitor: the BWU3367 gateway collects the safe signals from the 'PI world', while the BWU3683 does the same for the 'ODVA world'. Communication between the gateways and the 'translation' of the respective signals then takes place via Safe Link. This means that safe signals from one network can also be used in the other network.

Automatic gateway configuration

Up to 16 bytes can be transferred during communication between the two gateways. The devices are securely coupled by means of automatic configuration in the Asimon360 software. All you have to do is select the gateways to be paired - everything else happens in the background.

Mapping between Profisafe and CIP Safety via Safe Link enables the bidirectional exchange of safe signals.

© Bihl+Wiedemann

In order to implement the safe link between Profisafe and CIP Safety, the hardware and firmware of the corresponding gateways had to be adapted to the new requirements as part of a larger development project; the new functionality also had to be integrated into the configuration software. Mathias Bachmann, Product Manager at Bihl+Wiedemann, explains: "We normally transfer 4 bytes as part of Safe Link. We decided to completely redevelop the Ethernet/IP gateway so that up to 16 bytes can be transmitted safely between the devices. The Profinet gateway also underwent a series of improvements in order to meet the new, more stringent requirements that the safe linking of the two safety protocols places on the devices. As considerably more safe data is now transmitted, we have not only expanded the transmission capacity of the safety protocols, but also that of the standard fieldbus communication."

Reserves for OPC UA

compared to the first-generation gateways by a factor of 100," explains Bachmann, adding: "Thanks to the significantly increased computing power, we will be able to integrate an additional OPC UA interface into our gateways in addition to the functions mentioned above."

All in all, the interface will enable data access across all automation, IT, MES and ERP levels right up to the cloud. Components from different manufacturers can thus be networked in a standardized form and their data can also be processed, analysed and displayed on mobile devices such as smartphones or tablets. However, the higher computing power is not only required for applications in the smart factory; it also forms the basis for the implementation of increasingly complex safety concepts in ever more complex environments - for example in drive technology and robotics.

Author: Boris Indihar is an editor at Bihl+Wiedemann.