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Safe fleece packaging - Machine builder opts for AS-Interface and distributed I/O-based safety concept from Siemens for packaging plant
Emsdetten, Germany. Jürgens Maschinenbau GmbH " Co. KG based in Emsdetten near Münster took the decision to use a safety concept comprising a distributed I/O, AS-Interface and the ASIsafe from Siemens for the first time in a fleece packaging plant. This combination simplifies engineering, reduces the time spent on installation, increases flexibility and permits remote maintenance.
Jürgens Maschinenbau GmbH " Co. KG was commissioned by a customer to come up with a packaging concept to separate a mother roll of fleece into segments and package them as individual units. A safety fence measuring around 60 meters in length had to be installed for the enclosure – with six access doors and light curtains to ensure operator protection. For the project, the company decided to use the Simatic ET 200SP distributed I/O and the AS-Interface to monitor the safety devices for the first time in this type of fleece packaging plant. The solution was easy to implement using the I/O modules CM AS-i-Master ST and the failsafe variant F-CM AS-i-Safety.
The doors of the packaging system"s safety fence used to be safeguarded with mechanical switches connected to the fail-safe controller using conventional direct wiring. “That was laborious, complicated and led to a lot of faults,” recalls Christian Dunkel from the electrical department at Jürgens Maschinenbau GmbH " Co. KG. “Compared to the conventional wiring we used in the past, we can now achieve a 90-percent time-saving in our cabling work thanks to the AS-i solution.”
Rapid installation and flexibility
The packaging area at the end of the plant, which is equipped with 20 Sinamics S120 frequency converters, is safeguarded by six protective doors secured by Siemens Sirius 3SE5 position switches with tumblers. Also mounted are failsafe emergency stop buttons and three control keys for “Access Request”, “Area Acknowledgement” and “Restart”. They are connected as spur lines to the AS-i line using AS-i-M12 round connectors. Standard and safety-related signals can then be transmitted through a single two-wire cable, making installation flexible and above all fast. If the emergency stop button is pressed, a safe stop is initiated via Profisafe/Profinet without impacting on unaffected areas. Taken as a whole, Performance Level PLd is reached according to EN ISO 13849.
In addition to time savings, flexibility is a further major benefit to be gained by using ASIsafe in conjunction with the distributed I/O. For instance, additional safety devices such as light curtains can be simply incorporated into the safety concept. In addition, the upstream part of the plant can be easily integrated into the safety concept of the packaging system through failsafe input and output modules of the distributed I/O.
Fully integrated and safe
Instead of using a separate safety controller, a Simatic S7-300 controller with failsafe F-CPU is used in the packaging plant. “With this solution we are following the TIA philosophy with all of its advantages,” comments Dunkel. This also means reducing the number of interfaces and the time involved. For Dunkel, the major benefits of the project have included standardization of the safety concept and the speed of configuration, which takes place centrally using standard technology with Step 7. This means that the user requires just one engineering software system: for connection to AS-i-Master, ASIsafe and digital as well as analog inputs and outputs. The solution is also easily manageable in terms of the hardware required: Both standard and failsafe signals can be processed on the same hardware thanks to the use of the failsafe controller in conjunction with the distributed I/O. At the same time, Profisafe and the AS-I network ensure a failsafe exchange of data – also for remote maintenance. Particularly for a medium-sized company with around 250 employees and an export quota of 75 percent, the ability to monitor and adjust the safety equipment remotely is a decisive competitive advantage.
Jürgens Maschinenbau in Emsdetten opted to use ASIsafe in conjunction with an AS-I Master in the Simatic ET 200SP distributed I/O for the first time in a packaging plant for fleece rolls.
The standard operating stations and safety technology are simply connected as spur lines to the typical yellow conductor with the aid of an AS-i-M12 branch.
Sirius 3SE5 positions switches are offered with tumblers. The integrated AS-i connection allows them to be simply integrated into the safety concept using ASIsafe.
The supplementary modules CM AS-i Master ST for standard automation and F-CM AS-i Safety ST for safety technology are available for the Simatic ET 200SP compact distributed I/O.