Metal structures defined with Profibus

The increasing digitization of many manufacturing companies means that the complexity of measurement, control and automation equipment continues to increase. A control concept requested by the customer can quickly exceed the usual routine. The following example shows how, with good teamwork, a conventional metal heat treatment furnace has become a participant in the digital production network.

At the atomic level, metals form a fascinating cosmos. In a normal lattice structure, the atomic planes slide smoothly from one side to the other, or else they mutually block each other and become almost inseparable from each other. With alloys and heat treatment, humans try to produce the desired behavior in the exact amount. A working stage is of central importance and has always remained the same since the first forging: mechanical treatment, and controlled and defined heating and cooling.

This transformation of the internal structure of metals and alloys produces a variety of properties: surface hardness, temperature resistance, strength or ductility. Rarely, the material scientist is satisfied with the achievement of a goal, usually he must decide on a compromise. This has not fundamentally changed for many centuries and explains the importance of processes such as hardening, soaking, carburizing, nitriding or quenching of industrial applications today. Many experts have emerged in this area. One of these companies is Wilhelm Alte Gmbh, founded directly after the Second World War.

While the focus was initially on conventional heat treatment of parts by mass, today's range of services has expanded, most recently complemented by new processes such as laser beam hardening and spot welding. laser deposit.

With modern measurement, control and automation equipment

For more than 50 years, Wilhelm Alte has not only been dealing with metals, but also transmitting its know-how in furnace construction and industrial installations to its customers. The list of products requested and products is also long. This ranges from belt conveyors to vibratory hearth furnaces and chamber furnaces for soaking and annealing. Industrial furnaces are both gas and electrically heated and are always equipped with switching, measuring and control technology.

Normally, an industrial furnace is not a very complex measurement, control and automation system. Depending on the application, only a solid combination of temperature sensor, power controller and control panel is required. Nevertheless, the ever increasing variance and complexity in the customer's manufacturing operations is gradually becoming a challenge for the 80-employee company in the Sauerland region.

"We do our own cabinet construction and normal programming, because we attach great importance to vertical integration," says Wilhelm Alte's electrician, Mr. Junior. However, having a good order book combined with more complex requirements may involve more external partners.

"There were some tricky situations in a project at the end of last year," says Junior. The time pressure combined with a new technical territory: this was the moment when itsme Schultze & Erbse came into play. The need to put furnaces in different process control systems and with different bus systems led to the decision to do not buy "over-the-counter" measurement, control and automation products, but use a professional technical consultant. Due to old contacts, Junior chose itsme Schultz & Erbse.
 

​​​​​​​Addressing the thyristor controller

The first test case was a wire-drawing oven, at first glance a routine job. The know-how allowing the yarn to obtain the desired property is determined by the interaction of the reel and the unwinder with the temperature profile of the oven to be adjusted. All settings that are controlled by the user. "As usual, we created the circuit diagram and the control cabinet ourselves with this oven. However, the customer expects the oven to be controlled by a digital protocol using a Siemens touch screen and a special Siemens PLC. For us, it was a new territory in a phase where we were very busy, "Junior describes the situation.

In order to save time and control, the programming of the regulation, the panel and the control of itsme Schultz & Erbse must be taken care of. An S7-1500 was ordered for data transmission,which processes the furnace controllers via Profibus. Mohammed Alj, technical consultant for industrial automation at itsme Schultz & Erbse, took part in the project. It was also a new territory for him, because the control of several thyristors, which are used to control the energy consumption of ovens, is not trivial.

Context: A thyristor regulator reduces the rms value of the AC mains voltage by cutting the sinusoidal profile of the mains voltage at the end of each half-cycle because it still ignores some time after the zero crossing of the AC voltage. The thyristor power controllers are operated with a single-phase or three-phase AC voltage. The control controller changes the power-on time for the load.
 

Four ovens in one

First of all, Alj made sure that the necessary programs are updated via the TIA portal and installed on a stable computer. The next step was to map the process in the furnace and install the communication with thyristor controllers. "In principle, such a wire drawing furnace consists of four furnaces in one; two rooms with two temperature zones. These areas are controlled separately, "says Alj. To approach thyristor controllers via Profibus, we first had to work on addressing. Finally, we solved the communication of these two components on the special installation converters.

​​​​​​​For the fluid definition and reporting of variables, access control and rights allocation, good cooperation was needed in a tight schedule, which resulted in detailed documentation. "The project did not go without it, but we did it well together," laughs Junior, adding, "Mr. Aij has been a great support in the project. The next time it gets more complicated, I'll give it again itsme Schultz & Erbse.

Check out our other success stories:

Stay up to date with the latest news:

Take a look at these promotions:

Why not take a look at these trainings we offer:

You are probably also interested in these product groups:

Explore our competences, services and solutions for your success: