Greater efficiency with centralised compressed air control

Weidmüller GmbH & Co. KG is a family business that employs 6000 staff across the globe. At the company’s headquarters in Detmold alone, around 2000 employees are responsible for the manufacture and sale of many electrical connection technology products and solutions. In 2022 the electronics specialist generated over €1 billion.

Compressed air is required in the company for assembly processes, as process and control air as well as for electroplating. To this end, Weidmüller installed five separate compressed air networks, each featuring up to seven compressors and other components. The company primarily uses Boge compressors, but also uses air compressors by other manufacturers. The machines cover many performance levels within a pressure range of 7–8 bar. In recent years, the larger networks have been controlled using individual control, while the smaller ones have been controlled via a cascade control using pressure sensors.

Weidmüller recently approached BOGE because they wanted a control system that would incorporate all five compressed air networks and offer a better overview. Other requirements included a reduction in idling and thus increased efficiency. They also wanted to keep operating pressure and power consumption to a minimum.

In addition to the existing BOGE S 150, S 20, S 15 and S 29-2 compressors, there are two S 90-4s, one S 60-3 and one S 40-3 in use, which feature Boge’s focus control 2.0.

“We can read out the temperature, system pressure, network pressure and operating statuses directly at these machines,” said Jens Mühlbauer, project manager at Weidmüller. “This in itself is a huge advantage over older systems, which usually only display information about faults, load and idling as well as on/off.”

In order to meet the requirement of a single control platform, Weidmüller installed Boge’s airtelligence provis 3. The functionality and operation of the interlocking control were first trialled in a field test. This went so well that Weidmüller promptly decided to go ahead with a full installation for all five compressed air networks.

The new control system is backward compatible and integrates all models via Modbus, and via OPC UA offers secure communication with higher-level systems, for example, a control room or energy management system.

The control system is installed on an industrial PC and integrated in a switch cabinet. The individual networks are each connected to the new control system via a single patch cable, and within the network, the control communications are distributed to the individual compressors via Ethernet switches.

“We provided our own power supply units and Ethernet switches to further boost the signals from the control system,” Mühlbauer said. “The transfer rate is very high and the system is very stable.”

Less compressed air is required at Weidmüller on weekends and on public holidays. The control system regulates this intelligently: it automatically selects the optimal compressor combination and optimises the load and idle times. It can also manage fluctuating compressed air generation in different shifts, and over-compression can be avoided.

Energy management by the airtelligence provis 3 includes setting machine priorities. For example, a 90 kW compressor is connected to take precedence. It supplies Weidmüller’s entire electroplating shop with both compressed air and heat and must therefore run constantly. The whole control was programmed to optimise efficiency by continuously analysing the volumetric flow rate.

Users of the new control system can consolidate maintenance intervals, optimise running and be automatically notified when the integrated machines require maintenance.

“You can always keep your eye on utilisation, the current power consumption and the free air delivery of the individual systems,” Mühlbauer said. “In the past, I had to go to every machine to get the information locally.”

Another advantage has been improved energy efficiency. The electronics company has been able to increase this by 4–5%.

“That’s quite a lot in a system of 450 kW,” Mühlbauer said. “It is a significant improvement compared to systems that run purely via a cascade control or pressure switch — not least because the pressure can be reduced on holidays and at night using redefined pressure ranges.”

This can be done minute by minute and for every compressed air network separately, using a few touch commands, without having to laboriously search through the program. The information of the individual networks and compressors can also be displayed on several end devices.

Image: Weidmüller has installed five separate compressed air networks for numerous processes in the company, each featuring up to seven compressors and other components.