KELLER HCW MSR has developed a novel weighing and dosing control system for its mixing machines which offers distinctive advantages compared to standard commercial solutions.
The software developed by KELLER HCW works with machine functions based on nodal points whereas, in conventional control systems, the way the material is conveyed from the silo to the mixer via conveyors and weighing hoppers is rigidly predetermined. The advantage of this solution is clear: the control system only defines a start and end position combination and can determine itself the way the material shall be conveyed; e.g. when one of two conveying ways to the mixer is shut down, then the 2nd conveying way will be automatically chosen without requiring the operator’s intervention or an error message being initiated. This „Pathfinder“ principle makes a dynamic and autarchic administration of the transport ways possible while considering the respective operation status of the components involved. In case of short-termed modifications or completions of transport ways, only a test on the equipment components is necessary.
This control system consists in several modules and is based on a Siemens S7 PLC, thus utilising only standard components. This is also the case for the operating and visualisation systems. A simple programming device, already in use in many companies, is a sufficient programming tool for the final customer.
The object-oriented software is so flexible that it can be set up for a one-component weighing machine or for a mixing plant with several mixers and an almost unlimited number of silos, containers and manual dosers. The prevention against breakdowns is high since the control system is completely taken in charge by the PLC. The system can be operated with or without the visualisation or recipe PC modes.
Besides the dynamic administration of the transport ways, the control software developed by KELLER HCW offers another essential advantage: All equipment processes can be computer-simulated before the actual commissioning phase begins. Alterations can be agreed upon and made beforehand without wasting any products. Moreover, the personnel in charge can be trained in advance. This reduces the time required for commissioning of the control software to a minimum. After the equipment installation, only an examination of the software-hardware interface, i.e. an I/O test, must be done during the commissioning.
This new control system is available for all dosing and mixing equipment which KELLER HCW develops. These are for the most part machines and systems for the food, chemical and ceramic industries. The core competence of KELLER HCW plant construction division is the planning and construction of these control systems. However, it is conceivable to adapt the „Pathfinder“ to other applications in the machine and plant construction sectors.