Residual stack monitoring with Safeguard Detector

20. May 2016

Carton magazine: Making rigid housings a thing of the past

Requirements for protecting machinery have changed more and more with the increasing use of automation. In the past, protective devices in the work process were something of a nuisance; for this reason, they were often not used at all. Innovative technology has enabled protective devices to be integrated into the work process. As a result, they are no longer an obstacle for the operator and even help productivity in many cases. Reliable protective devices that are integrated into the workplace have thus become indispensable nowadays. They are a useful tool in achieving the goal of continuous production, which in turn improves system efficiency.



SICK developed the certified Safeguard Detector safety system as a means of ensuring flexibility when changing carton blank formats and providing protective safety technology at the same time. One application in which the new safety system for packaging machines can be used is carton magazines that require contact protection. When it comes to material transportation in particular (of flat carton blanks, for example), packaging machines present a risk of the operator reaching through an empty magazine and into the machine while it is still running, sustaining injuries as a result. Using Safeguard Detector, injuries may be prevented.



Reliable protection – even without material

The packaging material in the carton magazine of a packaging machine acts as a physical guard during operation. If there is sufficient material in the magazine, then it is not possible to reach into the mechanics while the machine is running. This protection ceases to function as soon as there is too little material left in the magazine, as the moving mechanics in the packaging machine are left exposed and pose a risk of serious injury. Until now, the only solutions available for this issue have been impractical in nature, either requiring the carton magazine to be installed at unreachable heights or involving extensive protective clothing, a mechanical tunnel occupying a great deal of space, and only a small number of format changes – or none at all.

A functional safety system

FlexiSoft_MultiPulseSafeguard Detector consists of the Flexi Soft safety controller and two MultiPulse photoelectric proximity sensors, which monitor how much material is in the packaging machine magazine. The sensors mounted at the side monitor the stack of cartons. If the level has reached an excessively low point, the system issues a warning so that it can be topped up in time to prevent the machine from stopping. The modular Flexi Soft safety controller evaluates the sensor signals. Certified function blocks that enable quick commissioning of the two MultiPulse sensors are available for the Flexi Soft. Additionally, the Flexi Soft gateway allows diagnostic measures to be implemented in several stages. These are useful for alerting operators in cases where, for instance, the magazine needs to be topped up or it will become empty within the next half an hour.

Space-saving magazine monitoring

The small sensor housings require hardly any space at all, making the carton magazine very easily accessible. The operator is able to keep topping up the magazine as the packaging machine is running. The compact MultiPulse photoelectric proximity sensors mounted at the side of the magazine establish new horizons for machine design, and format adjustments in the carton feed are easier to perform than in conventional systems. What is more, there is no mechanical tunnel at all. When a format change takes place, there is no need for any alterations in the layout of the safety-related equipment, as the side guides of the carton magazine consistently maintain the same distance from the contour of the format blanks.


carton magazines

The small housings used with the MultiPulse photoelectric proximity sensors require hardly any space.

Conforming to functional safety requirements

The self-testing process, which conforms to functional safety requirements, can only be ensured when all the components are working in a system. The two photoelectric proximity sensors provide the required pulsed signals, which are analyzed using the Flexi Soft safety controller. Thanks to the Safeguard Detector safety system, there is no risk of the operator becoming injured by reaching into an empty carton magazine.

An intelligent safety solution from a single source

Through its Safeguard Detector, SICK provides both pulsed sensors and intelligent signal evaluation with Flexi Soft in a single package. To make programming Flexi Soft a straightforward process, SICK has created special function blocks for each of the individual Safeguard Detector variants – allowing safety functions to be programmed simply using drag-anddrop. Sample programs are also available for integrating extended functions. Machine developers and plant operators can rest safe in the knowledge that they are using not only reliable, tried-and-tested components, but also a safety system that has been subjected to a safety assessment and is TÜV Süd-certified as PL d according to EN ISO 13849 as well as SILCL2 according to EN 62061.

Switch to autopilot

In addition to a straightforward presence signal, the MultiPulse photoelectric proximity sensors are able to indicate an error-free condition and the status of the application. This informs the controller that the sensor has detected the object with 100% certainty and thus that no defects, such as a wire break or sensor malfunction, have occurred. A simple oscillating circuit made up of the object, the optics, and the sensor electronics is what makes this possible. A second switching point ensures that sensor manipulation is virtually impossible. The controller monitors the oscillating circuit, which oscillates at 2 Hz or 10 Hz.



Modular and intuitive configuration: The Flexi Soft safety controller from SICK

The Flexi Soft concept offers a whole range of main modules, expansion modules, Motion Control modules, and gateways that can be used to create a customized, efficient solution for the safety application in question. It is also an efficient tool in the packaging industry, which uses machines with a large number of doors and flaps that require protective measures. Flexi Soft minimizes the amount of wiring work required in these applications. Not only that, but it also makes it possible to network overarching safety functions in modular machines – and integrate these into the standardized plant control system. The license-free Flexi Soft Designer configuration software offers intuitive programming, rapid commissioning, and continuous monitoring. The entire configuration can be documented in multiple languages at just the touch of a button.



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