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>> Article from the Wurm magazine “FreshUp 2/2022” (published in autumn 2022) <<
A gateway is usually associated with a simple device focusing on transporting protocols of an interface to another and at the most capable of transforming data to fit the structure of the recipient. One example is gateways that transform protocols from Modbus RTU to Modbus TCP and in order to achieve this also convert the physical connection from a simple serial RS 485 half-duplex digital interface to Ethernet. Such traditional gateways, which enable the coupling of another bus into the CAN network, can also be found for the CAN bus used by Wurm in the market. They just fulfill the functional task of a protocol transfer. As they do not understand anything of the application, these gateways are not “smart”.
Wurm gateways perform better than standard models with reduced ranges of functions
In contrast to them, Wurm gateways offer much more. On the one hand, they take over the task of a “gatekeeper” in the plant: nothing will pass unless it has examined it. At the same time, a Wurm gateway monitors the secure plant operation as a “supervisor”. Faults of connected devices are analysed according to their priority and origin. The forwarding of the alarms to the assigned alarm targets is carried out accordingly. Depending on the accessibility, up to five targets are possible, either simultaneously or staggered. Moreover, a Wurm gateway distinguishes 3 maintenance groups. In refrigeration plants and building technology systems there are often different responsibilities.
Malfunctions of devices in the system are also identified and reported according to the maintenance group by the intelligent Wurm gateways. If a control module cannot communicate because of missing supply voltage, it will be registered by the Wurm Gateway and reported to the responsible alarm target according to the priority of the malfunction. Different alarm outputs are available for the signalling on site, e.g., to the building services.
In a modern, networked system, innumerable data are transported via bus. They also contribute to the optimized function of the connected plant components. Wurm modules store large data sets for diagnosis or documentation according to the legal requirements. Single devices can retrieve these data via Wurm gateway. To prevent the bus from overloading during peak periods of the plants, the gateway is able to prepare the information and to transmit it in quieter periods. Similar to a logistics warehouse, stored data is packed in the gateway to be available for fast data retrieval at a later point of time.
Safety measures
In its role as a gatekeeper, the Wurm gateway is supported by various security measures aimed at preventing unauthorised access. The first safety barrier consists of the plant’s correct ID number and a password corresponding to the respective maintenance group. These unique passwords are individually appointed ex works. Their complexity has nothing in common with popular passwords (like “1234”) that are easy to crack and to be found in the documentation.
Additionally, a “fingerprint” based on individual identification is taken of each user intending to communicate with the plant. Only those who fulfil all security criteria and therefore have the appropriate authorization will gain virtual access to the plant.
Temperature documentation & Conversion of protocols
The Wurm gateway also has appropriate resources for temperature documentation, which is of high importance for food retailing. Up to 100 temperature sensors of the W-LINKpro type can be implemented by external recipients. Temperature values can then be documented in the gateway and thereby be available for HACCP reports in line with statutory requirements.
The diverse range of functions of the Wurm gateway also comprises the conversion of protocols. For a rapid response to requests for single data via a modbus TCP interface, our device retrieves the required information from the individual controller, translates data to the modbus format and transmits the information to the respective client according to modbus standard.
Multigate 3
With that range of functions, the Wurm gateway plays a prominent role in the configuration of a plant. The product name of our device for larger plants with increased gateway requirements is therefore justifiably appropriate – Multigate.
The efficient and smart device has now been completely reworked in its third generation and optimized regarding the costs. It is thus well equipped for future requirements – without waiving the scope of services. A second parallel processor with its own LAN port will carry out additional tasks soon, making the Multigate even stronger.
The powerful service package of the Multigate 3 has been accommodated in the housing in a space-saving manner, meaning it is even more compact than its “small brother” CMD300. Nevertheless, it fulfills all the functions you expect from a Wurm gateway: a gateway you can trust in – as gatekeeper, supervisor, guard duty and translator.
Sarah Schröter