CAN is the leading fieldbus communication solution in the automobile industry, yet its reach now extends to other products and industries, including robotics, medical and laboratory equipment, gaming machines, aerospace systems, and more.
For low-cost, lightweight, flexible network communications, CAN is an excellent option. Here’s what you need to know to determine if CAN is a good fit for your automation process or product development needs.
CAN is an acronym for Controller Area Network , a messaging protocol that allows different components of a system to talk to one another. It was developed in 1985 and established as an international standard— ISO 11898 —in 1993.
You can now find “classic” CAN as well as CAN FD, for Flexible Data , developed in 2011. CAN FD provides higher bandwidth of data by allowing dynamic switching to different data-rates and transmission of larger message sizes.
In order to send and receive messages, each device or node in the CAN bus network needs a CPU, a CAN controller, and a CAN transceiver. It is also helpful to have some I/O capability to allow the device to actuate devices or sense events or the environment.
Click here to view the PCAN-MicroMod FD - I/O OEM Module from PEAK System, a leader in CAN components, which can be easily integrated into an application. This compact device integrates I/O functionality into CAN and CAN FD networks allowing for customized OEM designs.
In automobiles, which now rely heavily on CAN technology, you will usually find three different CAN buses , although there could be more. The three are for the body of the car, the powertrain, and the information and entertainment system for radio, GPS, etc.
CAN is a multi-master serial bus standard for connecting
Electronic Control Units or ECUs, known as nodes.
Two or more nodes are required on the CAN network to communicate.
All nodes are connected through a two-wire twisted pair cable with a 120 Ω (nominal) characteristic impedance.
The CAN bus is standardized to allow multiple vendors to interconnect devices. The CAN physical layer defines things like cable types, electrical signal levels, node requirements, cable impedance etc.
Along with being well-established (in-market since the late 1980s, early 90s) and standardized (ISO 11898), CAN offers a relatively quick on-ramp to creating and maintaining networks that are both simple and robust, with several valuable advantages.
Reduced wiring, weight, and errors are three features that make CAN an economical option for network development and maintenance.
Since every network device has a CAN controller chip, modifications can be made faster and easier, with minimal overall impact. CAN also provides flexible data transmission.
CAN incorporates five error detection modes to identify and reject erroneous messages and enable re-
transmission of lost messages, as well as identifying and disconnecting nodes that consistently transmit errors.
Centralized
ECUs communicate via a single CAN system instead of multiple direct, complex analog signal lines.
The CAN bus provides 'one point-of-entry' to communicate with all network ECUs, enabling central diagnostics, data logging and configuration.
CAN frames are prioritized by ID so that top priority data gets immediate bus access, without causing interruption of other frames.
Like most technologies, CAN does have its weaknesses, which include:
Grid Connect engineers are happy to discuss these characteristics in regard to your needs and to offer ideas for workarounds or alternative options.
You may find information on the internet saying CAN is or will be obsolete, replaced by faster, more powerful Ethernet or 2 wire Ethernet, which may be the future.
Ethernet TCP/IP has its strengths, yet it still can’t deliver some key benefits that CAN bus networks deliver:
We believe the CAN bus protocol will continue to maintain a market leadership position for networking applications that require frequent, simple communications among connected devices.
If you believe or still wonder whether CAN is the right fit for your needs, don’t hesitate to contact us to discuss your requirements and objectives for your use case.
GridConnect has years of CAN experience, and we represent some of the leading manufacturers of CAN hardware components, like PEAK System and CSS Electronics. We can help you implement a CAN bus system that will enhance efficiency, streamline operations, reduce expenses, improve safety, and more.
Meanwhile, if you want to learn more about CAN, go to this knowledge page on the CIA website. (FYI, this won’t take you to the US spy organization, but to the international “CAN In Automation” association website!)
