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Automation Technologies 5/2016

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Automation Technologies 5/2016

Intelligent light

Intelligent light curtains for safe machinery About EPSG COMPONENTS AND SOFTWARE Stefan Hensel In production environments where humans work in close proximity to machines, conventional sensors provide insufficient active protection against injury for operators. By integrating innovative openSafety-based light curtains, the Ethernet Powerlink Standardization Group (EPSG) is opening up completely new approaches to safety for today’s manufacturing facilities. Light curtains have been used for many years now to protect operators of machinery and equipment. “Unfortunately, conventional light curtains are very inflexible,” explains Stefan Schönegger, managing director of the EPSG. They are known to hinder the implementation of modern design concepts where human operators and machinery actually work together hand in hand. It is for this reason that the EPSG developed an openSafety profile for intelligent light curtains. In 2016, Datalogic will be the first to bring these network-integrated light curtains based on the the new profile to market. No hardwiring necessary The intelligent light curtain is connected directly to the real-time Powerlink network. The overlying openSafety protocol replaces the hardwiring that used to be necessary for the light curtain. “Since no safe I/O channels are necessary, an application with openSafety light curtains is less expensive than a hardwired solution,” explains Schönegger. Author: Stefan Hensel, Public Relations, EPSG The Ethernet Powerlink Standardization Group (EPSG) was founded in 2003 in Switzerland as an independent association with a democratic structure. Its goals are the standardization, promotion and further development of Powerlink technology, which was first presented to the public in 2001. Powerlink is a patent-free, manufacturerindependent and completely software-based communication system for hard real time that has been available as a free open source solution since 2008. The EPSG’s Berlin-based office handles public relations, coordinates the implementation of shared projects and provides information for existing and prospective members. Intelligent single-beam evaluation Light curtains with single-beam evaluation, as they are defined in the new EPSG profile, provide an easier way. “When this type of light curtain is mounted at an angle, we are able to obtain all the data we need for intelligent muting,” says Stefan Schönegger. Based on which light beam is interrupted first, it is possible to determine the direction traveled by the product – without any additional hardware. The possibilities opened up by the openSafety light curtain greatly simplify the cooperation between humans and machines. Stefan Schönegger, Managing Director, EPSG AUTOMATION TECHNOLOGIES 5/2016

01a Conventional light curtains also require additional hardwired sensors in order to implement functions such as muting 01b An openSafety light curtain mounted at an angle eliminates the need for additional sensors and safe I/O modules; the light curtain is connected directly to the industrial Ethernet network The openSafety provides the controller with detailed information about which beam was interrupted and when. In addition to the product’s direction of movement, it is also possible to determine its height – and, using the transport speed, its length as well. Using this information, the safety controller is able to confirm that the product moving through the light curtain is exactly the one that was expected. If a person were to sit on a product in order to bypass the photoelectric sensor, for example, the machine would enter its safe state. “Solutions using conventional light curtains require a lot of technical effort in order to detect that type of tampering,” explains Schönegger. 02 As with safe drives and I/O, the openSafety light curtain is integrated directly into the safety network - wiring is reduced to a minimum Programmed in the engineering software With an automation solution using openSafety light curtains, safety functions such as muting and blanking are easily programmed in the development environment. Once an openSafety light curtain has been installed, the node number just needs to be set on the device. Conventional light curtains require tedious DIP switch configuration on the device or even the use of dedicated software. This becomes even more problematic once everything is installed, because the DIP switches are difficult to reach and represent a potential source of errors. Fast commissioning for equipment produced in series “The openSafety light curtains considerably reduce the amount of work needed for commissioning – especially for equipment produced in series,” explains Schönegger. This is because, once written, the safety application can be reused on every machine. The light curtain simply has to be connected to the network. The safety controller automatically detects whether it is dealing with the correct light curtain model and transfers the configuration to the device. Errors that might otherwise result from manual configuration or on-site wiring are prevented. “The troubleshooting possibilities of the intelligent light curtain are a huge step forward as well,” adds Schönegger. Error messages that used to require painstakingly reading and interpreting LED blink patterns can now be viewed in plain text. This allows for more detailed diagnostics and considerably shorter downtime. In summery, the highlights of intelligent light for safe machinery are less hardware necessary, shorter commissioning times, easy maintenance and wiring errors can be ruled out. Photographs: Teaser fotolia, 01-03 EPSG AUTOMATION TECHNOLOGIES 5/2016


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