What Is Can Bus Wiring?


Author: Lorena
Published: 23 Nov 2021

CAN Bus for Automotive Applications

CAN Bus is a controller area network that has two wires. The information within each vehicle is being transmitted. CAN Bus is built to handle robust performance in harsh environments.

Think about the people who are in the group. One ECU can send information via CAN bus to other ones that accept it. They will check the data after that and decide if they want to receive it or not.

The CAN bus standard is ideal for safety applications due to its reliability and resilience. There are 5 ways to detect errors in the CAN protocol. The image below shows a CAN frame with an 11-bit identification, which is the kind used in most automobiles.

The expanded 29-bit frame is the same as the larger one. Vehicles and machinery can be monitored. It can be done in the cloud.

Data can be provided for disputes or diagnostics. It is also called blackbox. CANopen is a type of embedded control that is based on a CAN and can be used industrial automation.

CAN Remote Frames and Optocoupler

The CAN standard has different message types. The messages use a clever scheme of bit-wise arbitration to control access to the bus, and each message is tagged with a priority. The purpose of the Remote Frame is to get the data to be sent.

If a Remote Frame is transmitted with the Arbitration Field set to 234, then the Data Frame might be responded to with a Data Frame. The type of bus traffic management that can be implemented with remote frames is request-response. The Remote Frame is not used much.

The CAN standard does not prescribe the behavior outlined here. CAN controllers can either be programmed to respond to a remote frame or to notify the localCPU. The maximum bus length is decreased if optocouplers are used.

Look at the delay through the device, not the maximum bit rate, if you use fast optocouplers. The measurement was done between the two. The bus voltages are 2.5 V when a dominant bit is transmitted.

Adjusting the Bit Rate of a High-Speed and Lowspeed Actively Driven, Multi-Antennin Network

The speed of the transition is faster with both high-speed and low-speed CAN, since the CAN wires are being actively driven. The length of the CAN network and the wire used are the main factors that affect the speed of the dominant to recessive transition. In automotive and industrial applications, high-speed CAN is used to run the bus from one end of the environment to the other.

Groups of nodes need to be connected together, and fault-tolerant CAN is often used. The noise, phase shifts, oscillator tolerance and oscillator drift mean that the actual bit rate might not be the nominal bit rate, even if all the CAN network's nodes operate at the same nominal bit rate. Since a separate clock signal is not used, a means of synchronized the nodes is necessary.

Synchronization is important during the course of the process since the other side must be able to see both their data and the transmitted one at the same time. It is important to Synchronize to make sure that there are no errors. The adjustment is accomplished by dividing the bit into four segments, each with a number of quanta, and assigning them to each of them.

The number of quanta can be varied by the controller and can be different depending on the network conditions. The test plan can be verified if the CAN transceiver with implemented wake-up functions conform to the specified functions. Conformance testing is the kind of testing defined in ISO 16845-2:2018.

Many higher layer protocols were created because the CAN standard does not include tasks of application layer protocols, such as flow control, device addressing, and transportation of data blocks larger than one message. All of them can be extended by each manufacturer. Each manufacturer has a standard for passenger cars.

What are CAN and Other Buses?

You know what a CAN message is, now you wonder what other messages are passed on the bus. There are four different message types allowed. The data frame, remote frame, overload frame, and error frame are the four frames.

Introduction to CAN Buses

The CAN bus is a common digital data network used in automotive, industrial, medical and scientific systems. The CAN bus is used for data transfer. The main advantages are high resilience to noise, reliability, low cost, and simple wiring.

The data packet lengths are small, transmission rates are low and the message transmission cycle time can vary. The video CAN Bus explained - A Simple Intro and theCSS Electronics article are both good places to start with a less technical introduction to CAN. They have an article on CAN with Flexible Data-rate.

The data is used by the vehicle'sECUs to process values. The values are different depending on the car manufacturer, the packets CAN id, and the values position within the packet. Parameter IDs or simply PIDs are some of the common packet values for emissions data.

The manufacturers have added their own custom values to the system. The use of custom values is used by car technicans when fault finding. CAN ground signals can be connected for a more resilient network.

The network may still function if one of the CAN high or CAN low wires is damaged. See the specifications for the ground lines. When bench testing short networks only one wire is needed.

The CAN Bus

Robert Bosch's CAN Bus has gained acceptance into the automotive and aerospace industries. CAN is a serial bus protocol that can connect individual systems and sensors. It allows automotive components to communicate on a single or dual-wire bus.

Since the early 1940's, the automotive industry has continually improved their technology by integrating more electronic components. As technology progressed, the vehicles became more complex and had more conveniences and safety features. Vehicles had enormous amounts of wiring which was necessary to connect all of the electronic components.

CAN Bus for Real-Time Networks

The CAN bus is a network technology that provides fast communication among the microcontrollers up to real-time requirements, eliminating the need for a dual-ported RAM in embedded systems. More information is available.

Auterra's CAN Bus Protocol

The newest CAN bus protocol is supported by all five of Auterra's Windows PC, Android and DashDyno SPD scans. The model year 2003 saw the introduction of can bus equipped vehicles. All vehicles sold in the US must use the CAN bus by 2008.

CAN BUS Protocol for Modern Car

Up to 70ECUs are available in a modern car. CAN is a serial communication bus. They are found in vehicles, farming equipment, industrial environments, and more.

CAN BUS communication protocol is more reliable than other communication protocols as they are used to transmit vital data like a throttle position in a vehicle. Critical failures could occur if miscommunication or loss of data occurs. Without CAN BUS protocol, electronic modules in vehicles will have to communicate with each other using point-to-point analog signal lines.

With each module requiring a direct line connected for communication, it will be messy with all the excessive amount of wiring as seen on the picture above. There may be unreliable communication between devices. Cost issues can be created by excessive wires and additional equipment.

A Model Railroad with Power Supply

If you use a command control or AC power, a small model railroad will run better if the power is supplied with a proper wiring bus and feeders. The bus has smaller wires that connect it to the rails. If you plan to run more than one train on your railroad at a time, bus wiring is a must.

The bus can be separated to provide for electrical blocks. There are many sizes of wire. The larger the wire diameter, the smaller the gauge number.

Solid and stranded wire are also available. Modelers are divided on the size and type of wire to use for a bus and feeders. Larger wires are more expensive and harder to bend and solder.

The length of the run is a key factor in determining a bus size. Shorter runs can use smaller wire. Bus wiring in most scales can be done with No. 12 to No. 14 wire.

The No. 18 to No. 24 can be used for feeders. Smaller scales are determined by size since the feeders must be attached to the rails directly. There would be a way to get to every section of the railroad.

Click Horse

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