Sharpening Water

Sharpening Water

The controller concept with SmartWire-DT help us to keep our prices constant despite the continuously rising material prices.

Achim Lucka, responsible for pump control at KMT Waterjet


Background
The principle of cutting with water offers a host of benefits. It allows the use of precise cutting speeds with flexible contours; material loss is negligible and finishing is often unnecessary. Furthermore it is a technology in which the material does not suffer on account of heat.

In order to enable the cutting of multidimensional contours, the waterjet cutting systems are as varied as the different application areas. KMT GmbH (KMT Waterjet) based in Bad Nauheim is a company that has specialized in the field of high pressure supply for waterjet cutting systems for over 40 years. The core of all waterjet cutting systems are the high pressure pumps. These are state-of-the-art high performance products that have to be adapted to the application at hand.

Challenges
Particularly when implementing the high pressure supply of cutting systems operating simultaneously, it is normal for end customers to run high pressure pumps in a network. An optimum network operation ensures that if a pump is switched off or fails, a neighboring pump can take over its operation automatically. This synchronization was important for KMT Waterjet as far as the development of an economical networking of high pressure pumps and their automation were concerned. The company therefore decided to choose a solution with a modular PLC, Eaton‘s XC-201, as well as the XVH-340 for visualization and operation. Eaton controllers such as the XC-201 come with interfaces like CANopen and Ethernet integrated as standard, so that KMT Waterjet was able to implement the networking of pumps directly via CANopen.

When the controller concept was reviewed, the aim was to increase overall efficiency. “We have been following the developments of the Lean Solution philosophy and SmartWire-DT for quite some time. The concept is innovative and we liked it straight away,” explains Achim Lucka, responsible for pump control at KMT Waterjet.

Solution
Together with Eaton, KMT Waterjet designed a new control concept which is used in all high pressure pumps of the company. The functionality of the previous two devices is now handled by the XV-102 HMI-PLC combination device. As a compact and powerful micro panel with resistive touch technology it offers a userfriendly solution for controlling pumps. The integrated interfaces include Ethernet and either CAN, Profibus, RS232 and RS485. The XV-102 can be programmed in compliance with the Codesys standard. Achim Lucka uses Eaton‘s Galileo software tool for the visualization, via which the web server integrated in the PLC can be configured for teleservice tasks.

The HMI-PLC communicates via SmartWire-DT with the control circuit devices of the pumps as well as with the DS7 soft starter which start up the main motors from 22 to 110 kW. Soft starters provide a compact alternative to the star-delta starter. Through a patented procedure, the startup is particularly smooth and yet at a higher torque than with other solutions. The SmartWire-DT interface allows the devices to be parameterized from a central point. Besides having a fault memory like the one typically found on variable frequency drives, the DS7 soft starter is able to detect nine different device faults and offer another 35 messages for communication faults. The DS7 with SmartWire-DT can also send an early warning and show details of malfunctions so that the operator can intervene in good time. KMT Waterjet also uses the data to prevent operating errors on the DS7 since the controller prevents incorrect settings.

Results
KMT Waterjet now keeps different programs for various hardware configurations for the machines on an SD card. With XV-102 the operator can call up the software on the touch panel. The controller then starts up and detects which machine configuration is active. This means that the operator no longer has to manually change addresses in the CPU via an external laptop. Consequently, employees no longer have to travel to the customer to install software updates, but simply send the program modifications by email.

“Thanks to its compact design, SmartWire-DT enables us to save space and minimize our costs for materials and stockkeeping. We also make additional savings since considerably less time is needed for assembly. This helps us to keep our prices constant despite the continuously rising material prices. “All in all, we benefit not only from the optimized costs but also from the additional ease of maintenance gained.”


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