Smart IoT solutions using CANopen in the edge controller | News
The IoT takes the approach of utilising new technologies and communication concepts to make data available in a cloud, link this data together and generate further value from it. The most common methods here are data transmission via MQTT or connecting data to the cloud using OPC UA. Current developments are taking this a step further and view edge computing as a means of automating and networking processes at the point of operation – that is, where data is generated: in industrial production, directly at the machine.
Why, and by what means and methods, is it worth going one step further? Should IoT be integrated directly into the device, into a machine component, or directly into the sensor and actuator systems? These questions are answered by Dr Frank Jungandreas, Senior Engineer at SYS TEC electronic AG, and Nadine Mensdorf, Product Manager at SYS TEC electronic AG.
Where do you place CANopen? What is SYS TEC electronic’s connection to CANopen?
Nadine Mensdorf: CANopen has long been established as a replacement for proprietary backplane buses within devices. On the market, CANopen can be found, for example, in specialised machinery, battery management systems, commercial vehicles, and in the lift and mobility sectors. Specifically, it connects sensors and actuators within a machine, transmits status values and process data, or triggers other actions. Just as CAN is used in the automotive industry, CANopen is employed in specialised vehicle bodies, such as fire engines, cranes or agricultural machinery.
Over many years, we and our customers have ported our CANopen stack to various controllers and end devices for a wide range of applications. Numerous customised developments and manufactured products incorporate our solution. We also utilise CANopen in current enquiries and projects, as well as in customer solutions. Our product portfolio includes our CANopen chip, the sysWORXX I/O modules based on it, and our industrial controllers. We offer end devices for use on DIN rails, embedded control units, and bespoke solutions. Alongside many other protocols, our CANopen implementation is used on all our IoT controllers with the IEC 61131-3 PLC programming system for communication at the field level. This applies to the sysWORXX CTR-700 edge controller as well as to the sysWORXX CTR-100 single-chip IoT controller.
CANopen and IoT – how do they fit together?
Dr Frank Jungandreas: The concept of the IoT is often initially explained in terms of linking data to the cloud and connecting devices to the cloud via protocols such as MQTT or OPC UA. But how does one effectively obtain cleaned, pre-processed data that is relevant for analysis? If we look at a plant as a whole, the data can often be delivered directly to the cloud via its control system. This brings us straight to the concept of edge computing – that is, decentralised data acquisition and processing – combined with gateway functionality, which serves as an interface to higher-level systems.
Under this approach, a machine in the capital goods sector is still viewed largely as a self-contained entity. Internally, however, it combines the functionality of several executive and monitoring devices, sensors and actuators. The intelligence for the Internet of Things must begin where the ‘things’ are located – that is, precisely where data is generated: namely, in the processes of industrial production, i.e. directly within the machine. If we consider the ‘things’ at a fine granular level as machine components with dedicated functions, we must begin by equipping the objects within the machine with intelligence and linking them together.
At the level of networking individual machines within an industrial production environment, Ethernet-based technologies clearly predominate. All objects are networked via this means. In contrast, however, this technology is scarcely used within a machine at the fieldbus level. There are many reasons why it often makes more sense to rely on CANopen within a machine rather than using IP-based technologies. For one thing, the vast majority of microcontrollers used in machine control systems today already have one or more CAN interfaces integrated. Data transmission via CAN requires significantly less energy than Ethernet-based systems, and there are numerous, cost-effective tools available on the market for commissioning and fault diagnosis.
The automotive industry provides a good illustration of just how capable CAN is. Within the vehicle, CAN is used to communicate the status of various components, transmit process data and trigger actions. At the same time, however, CAN provides an external service interface through which fault information and telemetry data can be read out. In the field of automation, CANopen offers just as many advantages for use within a machine. Lean, energy-efficient communication units can be integrated directly into the machine using cost-effective
So is CANopen making its way directly into machines? Please explain this in more detail.
Dr Frank Jungandreas: Exactly; many machines and devices use CANopen as an internal machine bus without this being visible from the outside. CANopen is significantly more streamlined, smaller and yet even more cost-effective than comparable IP-based communication. Furthermore, the power dissipation is also significantly lower than with Ethernet, for example. CANopen is therefore ideally suited to autonomous, e.g. battery-powered, devices. Applications in this area are set to increase significantly over the coming years.
Another area of application for CANopen is condition monitoring and predictive maintenance – that is, the continuous monitoring of device data to detect potential failures at an early stage and carry out proactive maintenance. Thanks to its integrated CAN interfaces, simple cabling and low energy and processing power requirements, CANopen can be integrated into any part of a machine with minimal effort. This enables our customers to implement smart ‘things’ quickly and cost-effectively. The resulting investment of time and money remains manageable, and the technological risk is low. Established support tools are also available, for example for diagnostics or configuration.
What does a specific example of this scenario look like?
Nadine Mensdorf: Within a plant or machine, there are several devices that need to be synchronised with one another. The individual actuators are interdependent. To ensure successful co-operation, the devices must be able to exchange information with one another regarding their process values, such as availability, power requirements and maintenance data. In the field of energy management, for example, power peaks can be distributed in such a way that high-power consumers are switched on one after the other rather than simultaneously, thereby significantly reducing the system’s current load.
CANopen connects sensors and actuators in a targeted manner; it transmits status values and process data and triggers actions. There must be no separate communication unit. Rather, this must be integrated directly into the intelligent sensors and actuators. For example, is a sensor operational, overheating or dirty? Which process is affected by the sensor’s availability? Can another sensor take over the task, or do the process values of the overall system – such as speed, etc. – need to be adjusted in this case?
Such intelligent assemblies are a must for new machines and plants, as they form the basis for predictive maintenance. A noticeable trend in the manufacturing industry is towards retrofitting – the installation of intelligent assemblies in existing plants. For machine manufacturers, this opens up new business opportunities; for users, it enhances investment security – even for existing plants. Machine manufacturers in the specialist machine-building sector, who currently see themselves as laggards, are beginning to incorporate smart modules into their machine designs. Manufacturers of sensors and actuators are designing intelligence directly into their devices – which in turn serve as supplements for existing plant.
Do you expect to see more retrofit solutions on the market in the coming years?
Nadine Mensdorf: Of course. The larger the investment in machinery, the longer it is typically used. In these sectors, the need for additional intelligence will continue to grow. Such a retrofit solution must always be considered in its entirety. Let’s recall the key features and advantages of CANopen. Intelligent, CANopen-compatible devices can be developed quickly and at low hardware costs. The components are technologically mature, meaning they carry a low technical risk – but also offer great potential for generating new lines of business.
Increasing pressure on performance and costs demands a rapid response, as well as proactive rather than reactive maintenance, in order to generate savings. The use of innovative technologies is not an end in itself, but serves to increase efficiency. The focus here is on identifying hidden costs. If these can be brought to light, it is possible to resolve the problems and reduce costs.
Just how easily an intelligent CANopen device can be implemented can be illustrated in a few simple steps. Let us take our CANopen chip as our first example. With this plug-in module, analogue and digital values can be read and output in seven available I/O configurations. The device profile for CANopen I/O devices, as well as the CANopen communication profile – in other words, the semantics of the unit – are integral parts of the CANopen chip. By integrating the CANopen chip into a control component, the latter can already communicate its process data in a semantically defined manner.
Let’s take our single-chip controller, the sysWORXX CTR-100, as a second example. In an intelligent machine component, we only need a simple I/O connection and the CAN transceiver for communication. All the intelligence required to read process data via CANopen, process it locally and forward it to a cloud via MQTT is already contained within the sysWORXX CTR-100’s chip.
When integrated into a sensor, it features self-diagnostic functions – it can process values and data it generates itself, as well as environmental data; control via CANopen; provide feedback to functionally adjacent units; and also push pre-processed values via MQTT to a higher-level edge controller. Data processing is increasingly shifting to the edge – that is, directly into the machine on the shop floor – and thus, naturally, into the ‘things’ themselves. Only through the targeted networking of individual ‘things’ can useful data be generated. The cloud alone is not enough – the application only becomes a business model when it is fed with the relevant data and this data is linked together.
With the sysWORXX CTR-700 edge controller, data can be acquired directly from the field level via CANopen and pre-processed locally. This information can then be forwarded via MQTT or OPC UA and thus transmitted directly to a cloud. Of course, other systems can also be integrated, such as process control systems, which collect, analyse and visually present the machine data in a clear and informative way. The data sets from the machine can also be supplemented with additional information – for example, environmental data – to provide an overview of the overall situation within a plant. This enables entire plant complexes to be monitored and controlled very efficiently.
