For industrial applications in the chemical industry, implementation of machine-to-machine communication and Industry 4.0 presents special challenges – not least in the area of compressed air supply. The main challenge is that the relevant standards have not yet been finalised. Yet already today, modern, adaptable networks enable optimal monitoring and efficient control of compressed air systems whilst ensuring compatibility well into the future.

To provide optimally efficient monitoring and control of compressed air systems, it is essential to know as much as possible about the processes that occur in the system. Sensors are the means to accomplish this, acting as the eyes and ears that communicate what they “observe” back to master controllers and process engineering systems, if applicable – ultimately enabling operators to gain maximum benefit from the data collected.

For successful data transmission within a communications system, the interfaces (which must be network-capable) are crucial elements together with the connected network, which enables effective data transmission. Yet this is precisely the area of uncertainty that compressed air systems operators face – when it comes to interfaces, standardisation of the components and protocols involved in process system automation is still in progress. Although strong tendencies have begun to appear, there are no defined standards, as yet. Faced with this uncertainty, many operators are deciding to wait and see where the chips will fall, instead of taking effective steps today to implement an efficient, contemporary compressed air supply – and especially one which is Industry 4.0-compatible and capable of adapting to future developments.

This paralysing uncertainty is unnecessary. Although the standard has not yet been definitively finalised, there are already existing systems available today that have the capacity to provide an efficient compressed air supply, save energy costs, prepare the company for full integration of Industry 4.0 and which are designed to support all future developments.

Ethernet: the new standard
Moreover, as of September 2016, the relevant standards organization, NAMUR e.V., already specified Ethernet use; which appears to be the defacto foundation for communications. Ethernet and the associated digital bus systems meet key user requirements throughout each phase of a system’s life cycle and compared to analogue systems, they are significantly superior in quality, cost and speed. Moreover, digital bus systems are a technical requirement for the implementation of ground-breaking Industry 4.0 solutions.

Seen in this light, there is no good reason to wait before investing in, and benefiting from, modern networks. Networks that enable rapid familiarisation and plug-and-play functionality are already available. Kaeser’s Sigma Network is one such network and is based on the Ethernet technology that opens up industrial communications and naturally enables IP-capable communication. Sigma Network also features additional, integrated innovation reserves that take into account future developments in the industry. The system is open to new protocols and can already support process engineering standards, such as Modbus TCP. Provided they are IP-based, future developments in the networking of process engineering systems are effectively covered. Because of the security of this investment, operators additionally benefit in the event of any future expansion or new installations – a key aspect for systems with long service life.

Rapid transmission of large data volumes
Kaeser Sigma Network also acts as a local network within the compressed air station enabling optimal integration and coordination of its components. The widely-used TCP/IP standard protocol – also known as the lingua franca of the internet – forms the basis of data transmission in Sigma Network. In contrast to common field bus solutions, such as Profibus, CAN or similar with relatively slow working speeds (e.g. 12 Mbit/s), the Kaeser Ethernet network is incredibly fast. It features a high data transmission rate of 100 Mbit/s which offers huge bandwidth for process data that will easily accommodate the large amounts of data generated as the digitisation process continues. Sigma Network is therefore definitely fit for the future when it comes to transmission speed.

Along with the (superordinate) Sigma Air Manager 4.0 master controller, Sigma Network constitutes a perfectly coordinated infrastructure for making data available for future services, such as predictive maintenance and yet more sophisticated energy management – which naturally cuts costs whilst enhancing operational reliability and availability.

Flexible access to operating data
If desired by the operator, the compressed air system operating data can be transmitted over a broadband connection to the system provider’s data centre (Kaeser Data Centre). This enables specialists to perform remote diagnostics on the compressed air supply and lays the foundation for future services, such as predictive, need-based maintenance. In combination, both features provide compressed air system operators with maximum operational reliability and availability, as well as minimal life cycle costs – because specialists always have their eye on the energy performance of the compressed air system and can adjust it for consistently optimal energy use.

Moreover, the operating data can then easily be integrated into the company’s own existing process engineering system, whilst flexible interface modules supporting current protocols and technologies enable on-site plug-&-play connection.

The system data can be accessed and viewed at any time, including from one’s own PC or laptop. The most advanced web technologies (HTML5, Javascript, CSS3) are employed to enable convenient browser-based access. Operators need only open the corresponding web address to access a complete representation of the compressed air system, including live view.

The fact that all data are constantly collected across the network means operators can practise precise energy management in accordance with ISO 500001 with the greatest of convenience. Simply by clicking the button on the screen, all necessary, pre-selected data is automatically generated and forwarded, if desired. It is also possible to configure the system to send automatic reports by email at predetermined intervals.
If desired, compressed air consumption comparisons, diagnostics and analytics can also be set up. The system data are stored internally for more than one year and can be used for evaluation purposes.

Network and data security
Naturally data security is always a central issue. Although it is difficult to assure absolute security, systems can be designed to provide an exceptionally high degree of security. The infrastructure, together with supplementary measures that complement it, ensures highly secure data handling. With coordination between the manufacturer and operator, this flexible system can therefore meet the requirements for availability, integrity and confidentiality expected of secure networked infrastructure.

Networks can be organised to create cell structures, i.e. internally, each component “talks” to every other component; however, at the same time, access in or out is restricted and highly controlled. Internally Sigma Network works with specific addresses and constitutes a closed, operationally-reliable network segment as per the recommendations for industrial control systems (ICS), in which only known communication participants are accepted. The Sigma Air Manager 4.0 (SAM 4.0) master controller is a central component of this communications network. The integrated measures result in effective data isolation between the internal Sigma Network running on an individual compressed air station and external connected networks.

If data are to be forwarded from the compressed air station, a defined secure transfer point is provided for secure data transfer to external partners. This separating feature acts to prevent attempted access to the internal station network. The data transfer direction is always from “inside” to “outside”. As such, this “data diode” prevents external data from entering the network since such incoming transfer might compromise reliable operation.

Conclusion:
Although the standard for the process industry has not yet been definitively established, Ethernet nevertheless appears to be the defacto basis of the systems of the future. Modern compressed air supply networks are already based on Ethernet technology and therefore already support future developments. They offer users a modern, efficient, reliable and powerful compressed air supply that yields impressive energy cost savings, as well as maximum convenience of use and operation. Moreover, such systems are able to accommodate future communications standards, facility growth and technical development, as well as increased capacity and transfer speed requirements.

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