The retrofit made it possible to visualize the entire packaging station in the central plant management system and to integrate all packaging processes into the ERP system. The integrated web server can also be used for remote access.
The modernization of the weighing controllers is part of an extensive retrofit of different packaging groups at the refractory sand plant run by EKW GmbH in the German town of Eisenberg. “We have replaced our entire control technology, transferring and adapting the programming of the old automation systems and adding the latest safety technology. Of course, the weighing controllers have also seen a generational shift,” explains Meik Wendel, PLC programmer at EKW GmbH. The company has been using B+L weighing controllers since the 1980s. “They have consistently proven themselves to be precise and reliable – and we also appreciate the great and fast support from B+L,” concludes Axel Deubert, manager of the electronics and maintenance workshop at EKW. This is a crucial point, since the individual types of refractory sand can vary greatly in terms of dosing and packaging due to differences in composition, humidity and granulation.
Luting sand (‘Klebsand’ in German) is an essential component of many products manufactured at EKW, such as sand mixes for refractory applications, self-flowing and cement-free refractory concrete as well as system solutions for the functional lining of different melting and heat treatment furnaces including their peripherals. EKW is a technological leader in the field of refractory materials, not only in steel and iron casting but also in various industries.
Keep operation easy, benefit from new features
The different types of refractory sand are produced in the central mixing system according to customer specifications or the intended application. From there, they are either loaded as loose bulk materials or delivered to the various packaging groups via conveyor belts and silos. “In these packaging groups, we use several centrifugal belt packers that pack the refractory sand into bags with a filling weight of 25 kg,” explains Meik Wendel. Each packaging group is operated by an employee who attaches the valve bags to the packaging spout and selects the appropriate set of pre-defined parameters for the type of refractory sand at the start of the bagging process. “
“Previous B+L controllers already had a high level of user-friendliness,” recalls Axel Deubert. “The employee had to do no more than select the type of refractory sand to set the necessary dosing parameters. This ease of use is something we didn’t want to miss after the retrofit.” It was mainly the increasing difficulty of obtaining spare parts that led to the modernization of the packaging stations. On the other hand, this also created an opportunity to leverage a next-generation weighing controller to implement a range of options and functions throughout the entire process control system that had not been possible before. The aim was to make the entire bagging process more transparent, to integrate it into the ERP system, and to ensure its sustainability with a view to future integration and documentation requirements.
Controller automatically adapts to variations
With the MID-approved miniPond 3F from B+L Industrial Measurements, EKW has opted for a verifiable weighing controller that provides precise and repeatable filling and dosing processes. At the push of a button, the operator can choose from a range of pre-settings that are saved on the device. That way, the weighing controller can quickly be switched to other products and filling weights.
Because of the different product characteristics and the application environment of the centrifugal belt packers at EKW, there are various features of the miniPond controllers that are particularly decisive: Their digital filter technology, the proven evaluation algorithms, and the smart free-fall compensation achieve the best possible filling results – despite any vibrations at the scales or refractory sands with varying density and consistency.
At the same time, each miniPond in the packaging groups automatically monitors and evaluates a number of process parameters contributing to the optimization of the plant, such as filling weight, tolerances and process errors. In addition, information such as count, total and diagnostic data can be logged on the controller. Even with all of these options, the weighing controller is easy to operate via its interactive menu interface. “This made for a straightforward commissioning process, which we were able to do in-house,” recalls Meik Wendel. “The connection to the scales and to the new higher-level automation system via fieldbus went smoothly, and after a quick operator training by B+L, all employees were immediately familiar with the new system.”
ERP integration and web server functionality
The miniPonds offer a range of integration options and can be flexibly integrated into almost any machine and control environment. “For the first time, this gave us at EKW the opportunity to link the weighing controllers to our ERP system and to replace the previous pallet-specific recording of the product quantity with bag-specific recording,” explains Axel Deubert. “The entire filling process is now controlled and documented up to and including the closing of the valve bag without any media disruption.
A further advantage is that after the retrofit, EKW can now access all miniPonds remotely. This is made possible by the integrated web servers of the weighing controllers. “We use this new functionality to connect the miniPonds of all packaging groups to the central visualization in our electronics and maintenance workshop,” says Meik Wendel. “We can immediately see how the system is running, which controller is doing what, and which error messages come up during operation. If necessary, we can log into the error history to retrace any settings, changes or operating errors,” explains Wendel.
In addition, EKW can also give B+L temporary remote access directly to the packaging groups via a browser, e.g. to set parameters, perform functional tests or diagnose failures. “If and when errors do happen, they can be fixed quickly, which ensures the availability of the plant,” says Axel Deubert. This access option also makes data backups and the firmware update easier to do. If needed, the miniPonds could also be integrated into condition monitoring applications at the higher control level, using the fieldbus interfaces.
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