Exchangeable machine modules make production systems more versatile. These can be assembled in whatever combination is required to produce a particular product. This mechatronic approach is not new. What is new, however, is the ability to assimilate integrated safety components. B&R’s Integrated Safety Technology makes this possible.
The goal of modular machine design is to reduce the cost of producing a custom machine by breaking it down to the greatest extent possible into noncustomized modules that can be produced in series. This is achieved by postponing the personalization of individual customer machines as long as possible in the production chain. The first step in this process is determining exactly what functions are needed. The results are mechatronic devices that are either permanently attached to the machine during final assembly or fitted as the application requires.
Mechanically, this isn’t a problem and happens all the time. If the electrical system is handled from a central control cabinet, there are a vast number of connections that require a complex set of connectors in order to be able to assemble the machine quickly. If mechatronic devices are the end result, then the fieldbus needs to be fast enough and/or decentralized intelligence is required. Ultimately, it should make no difference whether the individual components are in the control cabinet or decentralized. That goes for all of the automation technology being used, from the digital channels and motion control to the safety components.
Modular machines require extensive know-how
If we proceed with this approach, then there are two essential aspects that need to be taken into consideration for the hardware, the software and the development tool itself. The first is unrestricted hardware and software compatibility with identical timing. The second aspect has to do with the strict separation of software logic and physical hardware.
Compatibility ensures the decentralization of the hardware and the reusability of the software. Here, it doesn’t matter in the slightest if the components are connected from the control cabinet or if a machine module is connected decentrally via a fieldbus. There can’t be any deviation whatsoever in how the standard application or the safety application operates. From a technological point of view, this is the only way that the machine builder can freely design the mechatronic components.
The separation of software logic and physical hardware ensures the modular character of the automation system. The only thing that can define which hardware will be working with which software is the configuration. Most important, however, is that any number of configurations are possible. They can be generated both offline in the development tool or in real time on the target system.
All B&R products – including the Automation Studio development tool – meet these requirements thanks to the integration of openSAFETY and POWERLINK technologies.
In order for the features above to be implemented, a B&R hardware system constantly checks for the actual configuration. This is done in the asynchronous channel of the fieldbus without affecting the running application in any way. Once the controller has been switched on, the first cycle immediately delivers the current hardware mapping with diagnostic functions for each of the individual components. This includes information indicating whether the module is functioning properly, its serial number, firmware version, etc. In the simplest case, the configuration found corresponds exactly to the configured version and the application begins. If any deviations are found, the application itself can determine how to proceed during the initialization phase. This makes it possible to analyze the actual configurations found and select the necessary software functions. Only after this step has been taken does the runtime system start the real-time application.
Modularity made easy
“Modularity and decentralization with an integrated B&R solution is not only possible with this kind of extensive functionality, it’s also quite easy,” explains Franz Kaufleitner, who oversees the development of B&R’s Integrated Safety Technology. B&R’s safety solution also uses the same identification procedure. The only difference with regard to safety-oriented components is that when a configuration is found, it must first be manually confirmed on the operator panel, which sends an activation signal to the SafeLOGIC controller integrated in the system. This certified procedure makes it possible to achieve SIL3 and performance level “e” in accordance with the EN ISO 13849-1 standard.
This seemingly simple process then forms the basis for all kinds of new and useful features, as demonstrated by FERAG Verfahrenstechnik GmbH. Headquartered in Leipzig, this company supplies a wide variety of machines for printing and post processing. Since no two systems offered by the company are exactly the same, modularity plays an enormously important role.
Modules enable countless possible combinations
Beginning during the design stage, machines are put together as a series of modular building blocks, which are then grouped together by their technological function and installed in a complete system in a variety of combinations. One of the most widely used modules handles the detection of misaligned printed sheets; it can be used as often as necessary to ensure the quality of the final product. Other modules, e.g. for handling, transporting and outfeeding materials, are situated in many different ways depending on the type of system.
These complex FERAG systems also have the ability to detect hardware automatically. This requires an analysis of the topology and the different tasks assigned to the different modules when commissioning. During operation, this procedure is used as a simple way to turn off system components that aren’t being used, which further increases energy efficiency. “We don’t just use the automatic hardware detection feature to reduce manufacturing costs,” explains Stefan Schulze, software engineer at FERAG. “It’s also a major selling point to customers who value energy efficiency and usability.
Because every part of each system also comes equipped with safety functionality, integrated safety technology is also an extremely important consideration. “It goes without saying that machines have to be safe for the operator,” shares Mario Kroschky, manager of electrical design at FERAG, continuing: “At the same time, the safety of the machine and the product can’t be neglected either.”
In other words, it’s not enough to just shut the machine down when a safety violation occurs. Doing so may lead to uncontrolled axis movements that can cause severe damage to the machine. “If an orderly stop is initiated just a second too late at the speeds we run at, a machine can become so stuffed with paper that a hammer and chisel are needed to remove it,” says Kroschky. This makes an extremely short response time that much more important.
Changing machine modules during operation
While FERAG systems remain in the same physical configuration after their installation, things are a bit different at the company Heidelberger Druckmaschinen AG in the field of postpress (Heidelberg Postpress). With their Eurobind Pro and Stitchmaster ST 500 lines of machines, it is possible to remove, replace or add machine modules.
This is necessary, for example, if an order requires a different type of glue in the binding machine or if different system types need to be used in the Stitchmaster based on product requirements. The system operator only has to release the locking mechanism and attach a cable in order to carry out a reconfiguration. After being turned back on, the machine automatically detects the modification.
To further increase productivity and usability, Heidelberg Postpress machines also come equipped with Integrated Safety Technology from B&R. The only thing that the machine operator notices in this regard is that machine options have to be confirmed for safety reasons. In practice, setup is much more effective through the targeted use of intelligent Smart Safe Reaction functions. “We are able to offer our customers another real benefit that is only made possible through the use of Integrated Safety Technology,” explains Andreas Steinert, manager of electrical design at Heidelberg Postpress.
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