I/O Module simplifies setup and mobile use of fuel cell test stand

Turck’s TBEN block I/O modules with their own LabVIEW driver improve system flexibility and mobility in test stands for fuel cells at FutureE

“Battery storage alone will not be enough,” Siegfried Limmer says of the energy transition. “We will need both technologies in future, hydrogen and battery storage technology.” He is already noticing daily the growing demand for fuel cells as part of this trend. As managing director of the development consultants FutureE in Nürtingen, Siegfried Limmer works on the development of fuel cell systems together with his employees and partners. His customers come from the materials handling, automotive and commercial vehicle industries, but also from the energy or building sectors.

Test stand for the technology

To test its own fuel cell systems, FutureE developed a test stand similar to the one that could also be used in a laboratory environment. Testing in this case involves more than just a quality check after production. It is a major part of the development work since the efficiency of a fuel cell depends on several parameters which are run through in multiple iterations to determine the ideal operating parameters for different load scenarios of a fuel cell system.

LabVIEW: virtual standard for test stands

LabVIEW from National Instruments is virtually the standard software for extensive test procedures in R&D. However, LabVIEW is also used to run test stands in product development and increasingly also in parallel with production. “The programming required with a PLC is considerably greater, particularly when making calculations with array functions. LabVIEW also offers considerably more options than a PLC when it comes to designing the graphical user interface,” Albert Wais explains.

IP67 block modules with LabVIEW driver considerably simplify the creation and expansion of test stands
Siegfried Limmer | FutureE
Albert Wais (l.) and Siegfried Limmer in front of the test stand, which can be customized and expanded
Control cabinet of the test area is located close to the operator PC and can be made considerably smaller
A conventional Windows PC can be used to run the test stand thanks to the Ethernet/IP LabVIEW interface

Learning from industry: decentralized signal connection

Decentralized signal connections are now well established in industry as an alternative to point-to-point connection. I/O modules with IP67 protection are installed directly at the machine, capturing signals and transferring them to the controller via a single Ethernet cable. IP67 I/O solutions were previously rarely used for communicating with test stands, partly because the I/O modules designed for Industrial Ethernet can hardly communicate with LabVIEW. “Although NI offers a driver for Ethernet/IP, it is so basic that you can’t really work with it properly,” Albert Wais explains the situation. The fact that National Instruments does not consider Ethernet/IP as a priority for LabVIEW is understandable, especially since the software has only in recent years been increasingly used for parallel testing in production.

Unique: IP67 I/O modules with LabVIEW driver

Albert Wais himself was involved in the work to close this gap. Wais and co-workers from special machine builders Kirschenhofer wrote a LabVIEW driver for Turck’s TBEN-S decentralized I/O modules for a project for Kirschenhofer and Britax Römer. “This was a enormous task because we had selected for the RFID module in this project the most complex RFID module of the TBEN-S series.” The work, however, was worth it: Users can now find drivers for most of Turck’s IP67 I/O modules in the NI LabVIEW driver database. Wais consequently recommended Turck’s TBEN-S modules for the LabVIEW signal connection also for the test stand of FutureE.

End customer benefits from flexibility

Actuators such as for the cooling water controller and the cooling fan also have to be connected in addition to the signals for the sensors on the test stand. Flexibility is also ensured here thanks to the modules themselves. The DXP channels of the TBEN-S for example can be used as inputs or outputs without any configuration required. The use of the modular I/O system on the test stand also brings benefits for the FutureE customer. The system is handed over in such a way that customers can later run through their own test scenarios via the LabVIEW user interface, and these routines can be defined by the customer.

Conclusion

Managing director Limmer is just as pleased with the test stand project as he is with the I/O modules. “With every customer, requirements are different. One time we are developing systems for a forklift truck and another time for a heating system or a portable generator. These always involve different requirements, which we can nevertheless fulfill with the I/O modules. We therefore greatly appreciate the modules. They make our work easier.”

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