These solutions include the use of "Smart Process Gating" (SPG), a process developed by Leuze electronic that makes access guarding with material transport more compact, simpler and safer. When man and machine come together in a technical environment, it must be possible to stop machine and system parts within a fraction of a second. "The safety of all people working in one of our customers' many logistics centers around the world, whether in industry, retail or service, is the most valuable asset worth protecting," explains Stephan Schmid, project engineer in the Control Technology Development department at Witron.

This means that Witron equips the relevant areas with safety equipment or fencing to prevent such accident risks from occurring in the first place. However, since it is not possible to completely fence off all areas in a networked, mechanized system where people and machines meet, Witron works on conveyor lines with safety light curtains, for example. These must distinguish between people and goods.

The classic safety solution
Particularly in intralogistics and in the automotive and packaging industries, affected areas must be identified by optical safety sensors. In the past, muting processes with signal-emitting muting sensors were used throughout the industry to detect the approach of conveyed goods to a protective field and to bridge it at the right time for passage. These sensors were installed in addition to the safety light curtains and enabled pallets and conveyed goods to enter and exit without interruption. However, it is usually "tight" in front of and behind the safety light curtain. The additional use of bridging sensors usually meant that more space was required. The installation and service costs for their additional setup, adjustment and readjustment were also associated with additional work. "Witron therefore wanted to find a solution that combined process reliability, system availability and simple operation," explains Schmid.

Muting reinvented
At that time, Leuze electronic did not yet have a practical answer to this requirement, but already had a project idea: Smart Process Gating - based on its MLC safety light curtains. Leuze presented this to its key customer Witron at an early stage of development. Witron was quickly convinced and accompanied the development in numerous tests. Smart Process Gating was put through its paces at and by Witron on its test tracks in Parkstein and optimized together. "The result is impressive: a clever solution was created that combines the requirements of occupational safety with high process reliability and system availability," explains Josef Apfelbeck, Key Account Manager at Leuze electronic.

Smart Process Gating is a new method that makes muting processes simpler and more stable. With the SPG process developed on the basis of its MLC safety light curtains, the signaling sensors previously required can be dispensed with entirely. Conveyor systems can therefore be made more compact. In addition, the risk of misalignment or damage to the sensors is eliminated during the operating phase, as are the costs for their maintenance and servicing. This increases the availability of the entire safety system and also reduces other practical risks. With SPG, the first muting signal comes from the process controller (PLC), while the second is generated by the protective field itself. Smart Process Gating therefore requires a controlled material flow so that the necessary PLC control signals are made available exactly in the expected time window. The MLC 530 safety light curtain in the version with Smart Process Gating is certified by TÜV. In combination with a standard controller, a performance level PL d can be achieved, which is sufficient for many applications in intralogistics. With a safety controller, however, a performance level PL e can also be achieved.

Successful cooperation
Since the early 1990s, Leuze electronic and Witron have enjoyed a long-standing customer-supplier relationship based on trusting cooperation. "Many hours of hard development work, joint project planning, discussions and testing on the material locks of test conveyor lines with Witron as a strong partner at our side have led to a result that is impressive," says Apfelbeck proudly. Schmid explains: "What is particularly charming for Witron is the stability and high availability of the safety device - and that at a reduced cost. This is confirmed by our on-site teams as well as our customers." Since fall 2016, Witron has been using Smart Process Gating and this new technology as standard in all its projects worldwide - in the retail sector as well as in industry and service. Systems designed by Witron with SPG as a safety device can be found in France, Norway and the USA. Like everything that leaves the factory in the Upper Palatinate for the end customer, the safety modules were tested on Witron's test track. Witron also uses Smart Process Gating and other sensor solutions from Leuze electronic for internal training purposes: be it the AMS measuring sensor in the Witron high-bay warehouse area or the BCL 300 barcode reader for identifying codes.

The Leuze DDLS 500 data transmission photoelectric sensor with EtherCAT interface is a new addition to Witron's storage and retrieval machines. "Nothing leaves our company until we have thoroughly tested a new component or a new technology ourselves. We only recommend to our customers what has proven itself in practical tests - that is our philosophy," says Schmid: "The Smart Process Gating also had to pass numerous endurance tests. Today, it convinces us across the board and we use it as standard in projects involving material flow.

GIT Safety Award 2019 for Smart Process Gating
Witron and Leuze electronic are not the only inventors of Smart Process Gating to rely on the new SPG technology. A jury of experts with representatives from BHE, TÜV, VDMA, ZVEI, integrators and users selected Smart Process Gating as one of the top 10 winners of the GIT Safety Award 2019. The readers of the trade journals and online communities of GIT Sicherheit, GIT Security and messtech drives Automation even voted the SPG muting process, which dispenses with signal-emitting sensors, the gold winner of the award, which means it has also been nominated for the "Best of Industry Award 2019".