EtherCAT and XFC in photovoltaic production

PC-based control technology from Beckhoff is used in a wide range of conventional machine construction sectors such as woodworking machines and packaging machines, for example. More recently, Beckhoff has also been gaining ground in renewables sectors such as wind energy and photovoltaic production. In advance of the Photovoltaic Technology Show in Munich, Germany, PC Control talked to Andreas Schulze, Photovoltaic Business Manager at Beckhoff.

With its involvement in the photovoltaic industry, Beckhoff intends to conquer a new sector. What are the reasons?

Beckhoff’s involvement in the photovoltaic industry is based on long-standing cooperation with key machine and system manufacturers in this sector. Strong demand for solar modules and increasing cost pressure led to a wind of change in the photovoltaic market and to even stronger commitment from us. In order for photovoltaics to be able to make a significant contribution to our energy supply in the long term, production facilities, which in the past have been largely semi-automatic, must be upgraded. In other words, the whole supply chain for the solar industry should be automated. As a result, suppliers of automation solutions can expect a market with double-digit growth rates up to 2020. Our company has experienced double-digit growth over recent years, and in the photovoltaic sector we see scope for continued growth on this scale.

What market opportunities do you envisage?

To enable further growth in the sector, production costs have to be reduced while maintaining consistently high quality. This is possible by introducing open and flexible control technology in the production equipment, as offered by Beckhoff: PC Control is a versatile automation solution that can be used in all areas of the photovoltaic industry. With an extensive portfolio of Industrial PCs and fieldbus components, Drive Technology, TwinCAT automation software, the high-speed EtherCAT communication system and XFC, the high-speed machine control system, Beckhoff offers machine and system manufacturers a comprehensive range of solutions for this task. Only through advanced automation technology will the solar industry be able to reduce its production costs and expand its position in the global energy market.

What are the advantages of Beckhoff control technology for photovoltaic production?

The wide range of tasks involved in photovoltaic production such as wafer processing, cell production and module production not only require complex control solutions in the areas of handling, loading and unloading, transport, palletising and gluing, but also require networking of the individual manufacturing steps. PC-based control technology is inherently open with regard to hardware and software interfaces. This facilitates integration and networking of production modules without major cabling effort. For any application, the modularity and scalability of Beckhoff control technology offers a tailor-made control solution with regard to computing power, complexity and costs.

Beckhoff offers a wide range of hardware and software solutions for Motion Control applications. What are the requirements in photovoltaic production?

Beckhoff offers state-of-the-art Drive Technology and integrated automation software. This makes it optimally equipped for Motion Control tasks with stringent requirements in terms of dynamics and precision, which are common in the photovoltaic industry. Let's have a look at module production, for example. During stringing, solar cells are strung together and electrically connected. This process requires high-precision drive systems and measurement technology. The strings must be positioned with a tolerance of 0.5 mm to ensure that the module matrix can be transported to the next station, the fully automated welding station.

In March 2009, Beckhoff will make its first appearance at the Photovoltaic Technology Show in Munich, Germany. What are your expectations?

This trade show, which this year will take place in Munich for the fourth time, offers an excellent overview of machine construction and plant engineering for the solar industry. Beckhoff is control equipment supplier for many of the machine and plant manufacturers exhibiting at the Photovoltaic Technology Show. With our presence we intend to support our customers and also present ourselves as a partner for producers of wafers, solar cells and modules.

What areas will you focus on?

At the trade show we will present our complete range of automation solutions, consisting of Industrial PCs, Embedded PCs, the EtherCAT-based AX5000 drive system, EtherCAT I/Os and XFC technology. In addition, with TwinCAT control software Beckhoff will present a solution for controlling 3D robots for loading and unloading in automatic production lines for solar cells.

In which areas of solar energy has PC-based control technology from Beckhoff been used to date?

Our PC-based control technology has been used since 2001 in a wide range of applications such as wafer inspection, diffusion, antireflective coating and classification by the world's largest solar cell manufacturer and other companies from this sector.

The EtherCAT communication system offers outstanding real-time characteristics at low costs. What new control concepts does EtherCAT enable?

EtherCAT is the real-time Ethernet solution for industrial automation. The high-speed fieldbus system is characterised by real-time capability in conjunction with TwinCAT and low engineering and acquisition costs. In addition to cost benefits, EtherCAT also offers impressive technical opportunities, such as configuration of networks with different topologies. During classification of solar cells, for example, an EtherCAT line topology is installed in the corresponding plant section. Up to 48 classification stations branch off from these lines in a star configuration. In this way, it is possible to switch off a station without interrupting operation of the other classification stations or the complete plant section.

The extreme fast XFC control technology from Beckhoff enables process optimisation at the machine and a high degree of precision. What benefits does XFC offer for photovoltaic production?

Let's use the classification station example again. Solar cells not only have to be transported quickly, but at the same time they must be classified locally and in synchrony with the whole system. XFC technology – eXtreme Fast Control Technology – from Beckhoff offers a control solution that optimally meets these requirements. XFC utilises EtherCAT for data communication and offers control and I/O level components that enable cycle times of 100 µs, while at the same time allowing central intelligence to be utilised.