CANbus – the Key to Reliable and Efficient Data Transmission in Multiple Node Networks!
A Closer Look at CANbus Technology
CANbus (Controller Area Network) is a multiplexed wiring system used to connect intelligent devices, such as Electronic Control Units (ECU) on vehicles, allowing data transfer in a low-cost and reliable manner. Used as a serial data control network of ECU unit, it has been originally designed for the automotive industry. However, CANbus now finds its new practical application, becoming one of the most popular buses in industrial automation.
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CAN efficiently supports distributed real-time control with very high level of data integrity and communication speeds up to 1 Mbps. It allows network lines to connect up to 110 nodes. Meantime, the network distance with CANbus can be expanded up to 10 km.
CANbus also provides the extensive error processing mechanism for high level data integrity, i.e. the data transceiver and hardware error can be implemented by CAN controller hardware, which significantly protects the CANbus network from electromagnetic interferences. |
CAN protocol does not address nodes with physical addresses. Instead it sends messages with an identifier that can be recognized by different network nodes. Besides, messages with priorities of up to eight bytes in data length can be sent on a multi-master serial bus using arbitration protocol.
All these features of CANbus highly improve the reliability of network and the transmission efficiency.
RS-485 vs CANbus
In industrial automation different types of serial communication buses can be used, including the RS-232, RS-422, RS-485 and CANbus. However, for longer distance and higher bandwidth, CANbus can only compete with RS-485 interface.
Although these two buses adopt the same common twisted-pair as a transmission medium, they are quite different when it comes to their possibilities, including transmission quality, distance, costs, etc.
The main differential features are presented below:
Characteristic |
RS485 |
CANBUS |
Usage Factor of Bus |
Lower |
Higher |
Network Characteristic |
Single host node |
Muliple host nodes, irrespective of first of second |
Data Transmission Rate |
Lower (30scds/screen) |
Higher (3scds/screen) |
Fault-tolerance Mechanism |
N/A |
Reliable error processing & error detection |
Transmission Failure Rate |
Higher |
Much lower |
Infection of the Node Error |
Paralysis of the whole network |
No infection at all |
Transmission Distance |
<1.5km |
Maximum 10km with 5kbps |
Network Debugging |
More difficult |
Easy |
Development Difficulty |
Simple |
Need more technological skills |
Maintenance Cost |
Much higher |
Lower |
Benefits of CANbus for JetBox 8152 Users
The existence of CAN port in JetBox 8152 industrial communication computers allows users to have a reliable and efficient networking infrastructure. The main benefits are:
- Cost-effective - low maintenance cost of bus with high usage percentage
- Robust - anti-electromagnetic interference capability for operating in extremely harsh environments
- Long distance (10Km) and High speed (1Mbps) data transmission
- Network Flexibility and Expansion
- New nodes that are purely receivers and/or require only existing transmitted data can be added to the network without hardware or software changes
- Extensive and Reliable error checking ensures the real-time detection of transmission errors
- Receiving or screening the message intelligently by ID data
- Automatic send functionality of destroyed messages
- Messages distinguished by message identifiers which are unique to the network and define the content & priority of the message
Typical Applications
Unlike the RS-485 ports, which are mainly used in networks with maximum 1km distance transmission and fewer nodes, CANbus port is suitable for long distance multiple node networks. Primarily used in embedded systems, the CANbus port of JetBox 8152 make it a suitable solution for extending the networks up to 10km in noisy and harsh environmental applications which require high performance, highly secure and real-time data communication. Combining CANbus port, JetBox 8152 communication computers can be ideally used for manually controlled industrial networks.
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