Digitization of conveyor technology

Many people in this country regularly touch a product from SSI SCHÄFER, because the domestic waste bin they place by the side of the road often comes from this group. However, the prominence of their garbage cans should not lead to false conclusions about the group's product diversity, which coordinates the many sub-companies at its headquarters in Neunkirchen/Siegerland. With more than 80 companies and around 8600 employees, the group generates sales of around EUR 1.9 billion  and is now one of the world's leading solution providers for intralogistics. This is made possible by a product portfolio that today covers all the requirements of logistics – from sustainable container systems, through conveyor technology for small and large load carriers, to complex overall solutions in intralogistics, including software for in-house material flow and accompanying services.

Within the SSI SCHÄFER Group, the site in Graz, Austria, produces and develops container conveyor technology, among other things. At the end of 2018, Christian Steiner, Product Manager Conveyor Control, together with his colleagues, considered the requirements that the next-generation conveyor systems should meet. As a product manager, Steiner is also responsible for the automation and control of the conveyor technology. Hansjörg Lerchster was also part of the project team as Project Manager R&D. Today, Lerchster is responsible for the development of predictive maintenance solutions and other data-based services for intralogistics systems as Product Owner and Business Operations Manager at the start-up SupplyBrain, founded by SSI SCHÄFER.

Digitization of conveyor technology

The next generation of conveyor technology was to be automated and controlled digitally as far as possible. The previously used roller motors with analog control and the associated control modules could no longer meet the increased requirements. So the next-generation motor roller drives would therefore be controlled entirely digitally. Since Interroll, as a supplier and manufacturer of the motor rollers, uses the CAN bus, this fieldbus protocol was also set for I/O and control technology once the decision had been made in favor of this supplier's motor rollers. In addition, the newer motors would no longer be supplied with 24 volts, but with 48 volts. The higher voltage range would allow smaller cable cross-sections and, due to lower losses, longer cables and thus larger power supplies with better efficiency.

No perfect I/O solution on the market

SSI SCHÄFER was looking for systems on the market that could offer a data connection to the motor rollers with a CAN interface, the required 48 V voltage and Profinet communication for controlling the systems. The devices should be designed to be robust with protection class IP67 and suitable for direct installation on the conveyor belts. The perfect solution for this was not available on the market: "Although it was possible to buy CAN bus controllers on the market, we wanted an SSI SCHÄFER solution that was really tailored to our needs," says Christian Steiner. After we made initial contact with TURCK at the SPS automation trade fair in Nuremberg, the automation specialist checked whether it was possible to modify its own I/O solutions to meet the requirements of SSI SCHÄFER. Spoiler: it was.

CCU module saves separate I/O modules

The TBEN-LL-4RM-4DI-4DXP I/O module for the control of CAN roller motors, which was subsequently further developed by TURCK, is known by SSI SCHÄFER as a conveyor control unit, or CCU for short. In addition to the 48-volt voltage for the roller motors and 24 volts for traditional actuators, CAN communication to the motor and Profinet communication to the PLC, digital inputs and outputs for external trigger signals or actuators were another requirement. In addition to four classic I/Os, four DXP ports are available on the module, which can be used either as input or output. "With the module, we now have the option of collecting more sensor data, more precisely double the number of I/Os compared to the previous module. In the past, we had to use additional I/O modules from other manufacturers to collect the signals from the sensors," explains Hansjörg Lerchster, explaining the advantage of the new CCU. "Now we can combine all that. In addition, the bus communication makes the solution plug-and-play."

Automatic address assignment simplifies commissioning

Advantages are also evident in the simplified installation and commissioning of the CCU modules. "The address is now assigned automatically. We have received very good feedback from the plants under construction. The CCU module is easy to install and troubleshooting is also very good. The motor roller that is not working is displayed directly. This was not possible with the old technology," says Steiner, describing the feedback from his colleagues.

The introduction of the new motorized rollers has been gradually taking place since 2021. SSI SCHÄFER produces over 100 kilometers of conveyor technology annually. Motor rollers are integrated into various product groups, ranging from straight conveyor belts to curved and angled rollers to complex aligners. Due to the extensive changes and adjustments in the design drawings, this does not happen overnight.

Future-proofing and modularity

The CCU modules offer a wide range of optimization and automation options thanks to their digital control. The option of controlling the modules both via PROFINET and via I/O signals ensures a high degree of flexibility and backward compatibility. This flexibility enables the intralogistics specialist to retrofit older systems with the new technology. Not only could the motors be controlled more precisely via the fieldbus interface, but status data, such as temperature or operating parameters, such as their operating hours, could be transmitted in parallel with cyclic process communication of the operating data.

"With the new firmware of the module, we can control this not only via Profinet, but also via the I/O signals. This enables us to use the modules within the context of devices with software that cannot yet work with Profinet," adds Steiner. Although not every option is already fully used today, SSI SCHÄFER values the flexibility and future-proofing offered by the TURCK CCU module.

The project was launched by TURCK and SSI SCHÄFER in the middle of the coronavirus pandemic and thus precisely in the time of supply chain problems. "In addition to the improved cost efficiency and what we have achieved technically, the cooperation with TURCK was crucial for me. I have found them to be very cooperative and goal-oriented, and have enjoyed collaborating with them, despite the challenges that come with joint development," says Hansjörg Lerchster, recalling his experience working on the project. "We remain very satisfied with the ongoing activities, such as firmware updates, etc.," adds his colleague Christian Steiner. Based on the foundations that have been laid, further joint projects cannot be ruled out.

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