The Controller Area Network bus, or CAN bus for short, is a robust and reliable communication protocol that was originally developed for the automotive industry. Today, it is used in numerous applications, including mechanical and plant engineering.
For the cloud connection, the software module Universal Cloud Adapter is required. The Cloud Adapter can be installed on any Windows or Linux device (x86, x64 or ARM). The setup is explained in “Getting Started“. Alternatively, you can also use the AnyViz IoT Gateway.
CAN is a bidirectional 2-wire bus that works according to the “multi-master principle”. The two wires are known as CAN-High and CAN-Low and enable communication between all nodes in the network. This simple cabling allows nodes to send and receive messages without the need for a central computer. This not only reduces the amount of cabling required, but also makes the system less prone to errors.
FunctionalityThe functionality of the CAN bus is based on the transmission of messages, which are referred to as frames. Each frame contains a unique identifier and a payload of up to 8 bytes. The AnyViz Cloud Adapter records the frames sent by all nodes and sends the value changes of the configured data points to the cloud. A frame can contain several data points. If a data point is written from the cloud, the cloud adapter itself sends a frame with the configured identifier. This also allows values to be written to the CAN bus from the cloud.
A dedicated interface is required to connect CAN devices, which is only built into a few edge devices. You can find an up-to-date list of recommended devices under IoT gateways.
The CAN bus requires proper termination to avoid reflections and signal distortion. Make sure that termination resistors (typically 120 Ohm) are fitted at both ends of the bus cable.
All CAN nodes must work with the same bit rate. For longer cables or environments prone to interference, select a lower bit rate (e.g. 125kbits/s) to ensure stable communication.
