The CAN bus protocol is one of several approaches to solving a very basic problem — how can several electronic components scattered around a mechanical system share information?
Before protocols like CAN bus were developed, if you had a series of electronic components that needed to pass information amongst themselves, you had to set up a point-to-point network with a lot of wiring. Every device needed a connection to every other device if you wanted them to communicate.
This style of communication takes a lot of wiring, and it's not very flexible. If you wanted to add another node on the network, it's a big project!
There have been a lot of innovations in network communications since. Use of a host controller, for example, simplified wiring dramatically, but it introduced the complication of a host controller just to manage communications along the network.
CAN bus was developed by Bosch, and in 1991, the protocol was used in a production vehicle for the first time.
CAN bus uses minimal wiring, but does not require a host controller. Today, you'll still find CAN bus networks in vehicles, but they are also used in plant environments, assembly lines, medical machinery, and even in prosthetic limb automation!
CAN Bus allows various electronic components to communicate on a single or dual-wire network data bus up to a speed of 1 Mb/s.
Whether you're talking about the vehicle, or about wiring, "bus" is a shortened version of the latin word omnibus — containing or including many items. In wiring terms, a bus is any conductor used to direct power or information around a network. All objects plugged into the bus are electrically connected.
CAN bus is the name of the message-based communication protocol, but it can also refer to the physical bus used in the CAN network.
To try to avoid confusion, in this lesson we will refer to the protocol as "CAN bus", and the physical cable simply as the "bus." Together, all of the physical components — the bus and the nodes — make up the CAN bus network.
We won't mention the city bus again.
Multiple types of components may be used with CAN bus, provided they are CAN-capable, including:
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This lesson has been adapted from Kiril Mucevski's original published work, Automotive CAN Bus System Explained, with his permission.