Connected factories, MES/ERP/cloud connectivity, digitisation, asset monitoring and other next-generation trends are increasingly demanding for a seamless vertical as well as horizontal connectivity. This helps in providing easier access to assets on factory floor right down to sensors as well as machine-to-machine communication. It also enhances diagnostics and makes maintenance easier, thus reducing downtimes. Machines can talk to one another and take necessary corrective actions based on bottlenecks and breakdowns in the line. The perceived benefits from a connected shopfloor are immense. However, factories across the globe can only leverage these benefits after overcoming many challenges.
Challenges faced by factories
Connected factories, MES/ERP and cloud connectivity would all be just a dream and concept, if machines from different vendors cannot talk to each other and exchange data with upper layers. This brings us to the most vital aspect in realising digitalisation, which is machine-to-machine communication. Without machine-to-machine connectivity, though partly connected, a complete connected factory would cease to exist. This challenge becomes even bigger when we bring in brownfield machines and factories. Thus, leveraging next generation automation and technologies becomes challenging.
Machine-to-machine and machine-to-cloud connectivity are playing vital roles in factories’ aspirations of becoming connected and moving to smart manufacturing. A couple of years ago, we too moved from mobile phones to smart phones. This transition was somewhat easy as it was fueled by consumers or market demands as well as was driven by the choice of individuals.
In addition, the changeover time, effort, cost was negligible as against the benefits in store. Today, we are talking about smart homes and connected appliances with Alexa, Siri and Google Home. However, our houses are equipped with hundreds of appliances, which might not be connectivity ready. To make our houses smart, just adding devices, such as, Alexa, Siri and Google Home will not be enough and we need to plug all other appliances to the internet to truly leverage the benefits of smart home. This approach provides decentralised intelligence and control and at the same time, offers appliance-to-appliance connectivity.
Similarly, when we talk about a factory, this becomes more complex and it is impossible to change running systems with new systems, as the capital investment needed is immense. The question factories face is how to move forward and achieve horizontal and vertical connectivity without huge investments in their endeavour to become smart.
Vertical and horizontal connectivity
Factories definitely face challenges but overcoming them is not impossible. It is necessary for factories to systematically move forward and draw a roadmap for building smart factories and making brownfield sites, smart. Even in Greenfield installations, factories need to choose from available technologies. In both scenarios, open source connectivity solutions provide a pertinent platform for factories helping them achieve seamless vertical and horizontal connectivity. Open source solutions help in providing vendor independence and reduce the total cost of ownership. This provides immense possibilities for automation vendors, machine builders and factory operators.
Vertical connectivity helps factories move data from machines to upper layers for analytics. Many factories do not wish to move data to cloud and wish to stop at IT level in a factory. Thus, their need is for connectivity until MES/ERP. On the other hand, some wish to move data from these IT layers into the cloud. In addition, some factories go a step further allowing individual machines to connect to cloud and exchange data. Open source, vendor independent communication is the way forward for satisfying these various needs of factories without placing any dependencies on any vendors. In addition, factories would have the necessary data from individual machines enabling them to calculate overall equipment effectiveness, monitoring energy consumption and line condition for improving availability and productivity.
Horizontal connectivity enables factories to talk to one another and exchange important field data and parameters. A breakdown in a line usually halts the entire line and creates a bottleneck. Stopping an entire line usually leads to wastage, longer downtimes and higher re-start times. With horizontal connectivity, operational line machines can reduce their speeds and keep working with lesser productivity and throughput, while maintenance teams focus on resolving the breakdown, thus helping in avoiding wastage and downtime. In addition, data exchange of various parameters can be enhanced and calculation of overall line effectiveness be made possible.
Open source, simplifying connectivity
Factory operators, over the years, were vendor locked and were forced to use connectivity solutions offered and promoted by automation vendors. The proprietary nature of most of the available connectivity solutions was a major deterrent in seamless data exchange. This has led to factories increasingly turn to open source solutions for seamless connectivity.
OPC UA (Unified Architecture), MQTT and AMQP are a few protocols enabling factories with vertical connectivity. The open source nature helps them to be adopted by any vendor. Even cloud platforms are using these protocols as a default for exchanging data with factories. This makes it easier for factories to move data from machines to IT or to cloud without protocol converters and additional gateways. This drastically reduces the infrastructure cost for factories. As long as machines in a factory continue to operate as relatively self-contained units – sending and receiving isolated diagnostic data and commands – OPC UA will continue to be an excellent choice for M2M communication. In addition, OPC UA provides all the necessary security mechanism needed for IT systems and cloud connectivity.
Maximising productivity with determinism
In addition, OPC UA TSN (Time Sensitive Networking) provides real-time connectivity even in large IT networks, security, plug and produce architectures and pub/sub mechanisms. Until now, OPC UA has had its limitations when it came to complex processes with real-time requirements. Thus, OPC Foundation and the Industrial Internet Consortium (IIC) are working on two extensions that aim to give the OPC UA communication standard real-time capability: A publish-subscribe model and utilisation of IEEE 802.1 standard for time-sensitive networking (TSN). OPC UA TSN provides a real-time connectivity even on shopfloors, which was until today non real-time. B&R has tested the future OPC UA TSN standard intensively in cooperation with TSN network specialist TTTech. The tests revealed cycle times under two milliseconds and a jitter of 100 nanoseconds. Time-critical applications at the line level, such as, synchronisation of conveyor belts with various other equipment, can therefore, be implemented without any problems. OPC UA TSN is envisaged as the unified protocol for Industrial IoT communication down to the controller level.
Until now, OPC UA has used a client/server mechanism, where a client requests information and receives a response from a server. This system has its limitations in cases when there are many nodes on the network. The publish-subscribe model, in contrast, enables one-to-many and many-to-many communication. A server sends its data to the network (publish) and every client can receive this data (subscribe). The publish-subscribe model alone is insufficient for achieving OPC UA real-time capability. Automotive industry is already driving development of TSN and the required semiconductor components will be available very quickly and relatively inexpensively. The automotive industry would also like to handle all control tasks and applications that require functional safety over Ethernet. For this to be possible, they will need cycle times in the real-time range and deterministic network behaviour.
IT meets automation
OPC UA is already providing factories with horizontal or machine-to-machine and vertical connectivity. With OPC UA extending its reach to line automation, there will be some dramatic changes to the structure of machinery and equipment. Traditional factory-level fieldbus systems will no longer be needed. The combination of open source OPC UA TSN and POWERLINK will cover the full range of communication in industrial production.