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 that complies with the applicable standards and norms in order to prevent accident risks from occurring in the first place.

However, since it is not possible to completely fence off all areas where people and machines meet in a networked, mechanized system, Witron is working on conveyor lines with safety light curtains, for example. These must reliably 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 ensure that the approach of conveyed goods to a protective field is clearly detected and that it is bridged 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.

Process-controlled access guarding in the packaging industry. © Leuze

However, space 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, making the system less compact. 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.

Reinventing muting
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 a very early stage of development. Witron was quickly convinced by this idea and accompanied the development in numerous practical tests. Smart Process Gating" was put through its paces at and by Witron on its test tracks at its company headquarters in Parkstein in the Upper Palatinate and jointly optimized in detail.

"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 and specialist for intralogistics at Leuze electronic. With "Smart Process Gating", a new process was created that makes muting processes simpler, more compact and more stable.