CAN VIA RADIO: RELIABLE DATA TRANSMISSION FOR ALL CAN BUS PROTOCOLS

CAN is established as the standard for data communication in numerous industrial applications, from automation to wind turbines, in crane technology, mobile work equipment and many other areas of use. The more mobile, flexible and agile the applications are and the more important fail-safety and freedom from maintenance are, the more worthwhile is the use of wireless communication as an alternative to cable . We show you what you should know about this and how you can replace existing solutions with CAN bus data transmission via cable, drag chains or slip rings with radio data transmission.

What is CAN?

CAN - Controller Area Network - is a protocol for networking controllers with sensor and I/O modules. The fieldbus system was originally developed for automotive applications and is also widely used in automation and other industrial areas. Separate communication protocols such as CANopen and DeviceNet as well as J1939 for the commercial vehicle sector have become established for this purpose. In addition, there are protocols for special applications, such as CANopen-Lift for lifts, ISOBUS for agricultural applications and FireCAN for fire engine superstructures, as well as customised and self-programmed CAN protocols.

How does CAN work for data communication in industry?

The CAN bus was developed as a message-based protocol with which several equally authorised control units can be connected. In general, all messages from the controllers are transmitted to all participants, each with a message ID and the content of the message. By means of the ID, recipients recognise whether the message is relevant to them or not. Depending on the application, there are two defined formats for message IDs - also called identifiers: 11Bit (CAN 2.0A) and 29Bit (CAN 2.0B).

What should be considered when replacing an existing CAN data transmission with CAN by radio?

Radio solutions are ideally suited for networking mobile applications, rotating parts or flexibly constructed systems via CAN bus.  However, not every radio solution is equally suitable for this. Via Can-Bus, all messages are sent to all participants as described. Depending on the number of devices in a network and the frequency of data transmission, this can lead to too high a load on the radio link - and thus to fieldbus errors and, in the worst case, to a standstill of the system. To prevent this, Schildknecht has developed the patented DATAEAGLE technology, which differs from conventional radio alternatives for CAN data transmission. The intelligent data radio offers pre-processing of the data packets and further procedures to reduce the required bandwidth. This ensures interference-free data transmission with minimal latency as well as a reliable and fail-safe radio link, even with short radio interruptions. DATAEAGLE supports both point-to-point connections and complex networks with multiple controllers and I/O units.

This is how DATAEAGLE differs from other radio solutions and creates reliable and stable automation solutions with intelligent data radio . Read more

How whitelists and ID collection reduce the bandwidth for CAN data transmission by radio

In addition to pre-processing the data, DATAEAGLE from Schildknecht offers the possibility of defining via whitelist and based on the message IDs which messages are to be transmitted via radio and which are not. In this way, the required bandwidth can be significantly reduced if necessary.

In addition, the DATAEAGLE radio systems can optionally transmit data in two modes: "ID Transparent", where all message IDs - even those received twice - are transmitted, and "ID Collection". In this mode, the transmitter collects all messages received on the cable side in a buffer memory and overwrites them each time with the latest messages with the same ID. During the next radio transmission, only the most recent message is transmitted. This is particularly useful for rapidly changing data and helps to significantly reduce the required bandwidth - e.g. when transmitting sensor data where only the latest status is relevant anyway.

Which radio technology is suitable for the CAN protocol

Depending on the application, required transmission speed and range, different radio technologies such as Bluetooth or 869 MHz / 915 MHz are suitable for CAN data transmission by radio. DATAEAGLE is available in different versions and, depending on the technology, enables radio distances of up to three kilometres and - thanks to intelligent data pre-processing - with CAN baud rates of up to 500 kbit/s.



Out of the radio data jungle: How to find the right radio system for your application. We answer this question with the project guide, including a questionnaire that you can send to us.

How is a radio system configured for CAN bus communication? And how can I see which baud rate and which CAN identifier are used?

DATAEAGLE is Layer 2 transparent and supports all CAN protocols such as CANopen, DeviceNet as well as customer-specific protocols. Furthermore, the devices support all baud rates from 50k to 500k. A special feature of the DATAEAGLE systems is their plug&play functionality: they are simply connected like a cable, connect automatically and recognise the baud rate on the CAN bus via the autobauding function as well as whether an 11bit or 29bit identifier is used.  Users do not need to know which baud rate and which identifier are used. However, you can get this information quickly and easily via the diagnostic function of the DATAEAGLE systems.

Quote from a customer: "Unfortunately I don't know the baud rate of my system, so the autobauding function is an important relief in the commissioning process."

DATAEAGLE: Plug & Play setup and configuration for CAN via radio.

Manual configuration is not necessary with the Plug&Play-capable DATAEAGLE systems. Nevertheless, they offer the option to set baud rate, whitelist entries and format as well as the operating mode (ID Transparent / ID Collection) via the DATAEAGLE Wizard. To do this, the units are connected via USB cable to a PC on which the DATAEAGLE Wizard software is installed. CAN parameters and features can then be changed in the programme. In addition, CAN parameters such as baud rate, load etc. can be read out via the diagnostic terminal during the application. In this way, users or integrators can see, for example, which baud rate is being used and how high the load on the radio link is. The latter information indicates whether it makes sense to use a whitelist to reduce the load on the radio link.

Service ID enables dynamic configuration from the application and during operation

As a special feature, the DATAEAGLE systems also offer a service ID via which CAN errors can be queried. It can also be used to make dynamic changes in the network via the CAN bus and during runtime. A service ID can be sent from an application, which then parameterises e.g. participants, functionalities and roles in the radio system. This function is exclusively possible with DATAEAGLE systems and increases the flexibility of network and applications.

Video: Plug & Play

Upgrade your CAN data transmission - with DATAEAGLE and intelligent radio data transmission.

CAN protocols can be transmitted by radio. With DATAEAGLE, you thus achieve maximum reliability and stability of the radio link and benefit from quick and easy plug&play installation. The intelligent data transmission, flexible operating modes and additional functions such as configuration during runtime make DATAEAGLE the optimal solution for wireless data communication - also in your project.

At a glance: DATAEAGLE offers these advantages for CAN via radio

• Stable radio links and intelligent data radio: With patented pre-processing, ID collection and whitelists for data transmission.
• Plug&Play setup and configuration: DATAEAGLE is layer-2 transparent, can transmit all CAN protocols and automatically detects the set baud rate.
• Diagnosis and parameterisation via GUI: The DATAEAGLE Wizard PC software and the service ID of the DATAEAGLE systems enable quick and easy read-out and parameterisation as well as diagnoses of cable, radio link and bus errors.
• Configuration during runtime: Dynamic change of network, participants and functionality - with data transmission via DATAEAGLE's own service ID.

Can you replace your existing data communication with radio? Try it out!

Write us your requirements. We will quickly and easily send you a test system with which you can test data transmission by radio directly in your application.

Of course, our experts will also support you personally in the selection and implementation of your radio solution. You can reach us by phone at +49 7144 89718-0 or by e-mail at sales@schildknecht.ag. You are also welcome to use our chat. We look forward to hearing from you!

> > Subscribe to the blog here & don't miss any new articles!