What Is Can Bus?

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.

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.

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 Open and Can Fault-Tolerant Protocols for Dynamic Systems

It is an ideal protocol when a complex system is needed. It reduces the cost and weight of the wiring. The cost of the chips is low, and the protocol is clean, making it easy to implement CAN.

The CAN standard was introduced in 1986. The automotive world was changed forever when Intel began to sell the first CAN controller chips. The weight savings that resulted from the development of CAN were almost a lucky by-product, but still very real.

Data cannot be sent directly to each other. They send their data to the network where it is available to any of the other networks. The CAN protocol uses a bitwise method to resolve contentions on the bus.

Multiple nodes can transmit at the same time. The lowest message ID number is the priority. The CAN bus has two bits.

It is used for fault-tolerant systems that do not require high update rates. The maximum data transfer rate is 125 kbps, but the wiring is more economical than high-speed CAN. Low-speed CAN is used in automotive applications for diagnostics, dashboard controls and displays.

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.