RFCAN vs LIN Bus: Key Differences and Applications
CAN (Controller Area Network) and LIN (Local Interconnect Network) are both communication bus types used in automotive and industrial applications. However, they serve different purposes and have distinct characteristics. Despite their differences, they also share some similarities:
- Both CAN and LIN are message-based communication protocols, meaning that data is transmitted in discrete messages or frames.
- Both use serial communication methods, which are efficient for long cable runs and help reduce electromagnetic interference.
- Both bus types can be integrated into microcontrollers and automotive electronic control units (ECUs) to provide hardware support for communication.
- They can also coexist in the same system, with LIN often interfacing with higher-level CAN networks to control peripheral devices.
Let’s delve into CAN vs LIN bus types before we explore the differences in detail.
What is CAN Bus?
CAN is designed for high-speed, real-time communication and is used in applications that require fast and critical data exchange such as engine control, transmission control, and safety systems (e.g., ABS, airbags).
The CAN bus system enables each ECU to communicate with all other ECUs without complex dedicated wiring. An ECU prepares and broadcasts information (collected from sensors) via the CAN bus.
The CAN bus consists of two wires: CAN low and CAN high.
The broadcasted data is accepted by all other ECUs on the network. Each ECU can then check the data and decide whether to receive or ignore it. CAN bus specifications are described by the physical layer (ISO 11898-2) and data link layer (ISO 11898-1).
Here are the key features of the CAN bus protocol:
- CAN nodes are connected via a two-wire bus.
- Supports baud rates up to 1 Mbps (Classical CAN), 5 Mbps (CAN-FD), and 10 Mbps (CAN-XL).
- Supports maximal CAN cable lengths between 500 meters (at 125 kbit/s) and 40 meters (at 1 Mbit/s).
- The CAN bus must be terminated using a 120 Ohms resistor at each end of the bus.
What is LIN Bus?
LIN is designed for low-speed, non-critical communication and is typically used for functions like interior lighting control, wiper control, and other simple, non-essential vehicle or industrial tasks.
The LIN bus is a supplement to the CAN bus. It offers lower performance and reliability but at lower costs.
Key features of the LIN bus:
- LIN bus uses a single-wire communication channel.
- The first LIN specification 1.0 was released in 1999 by the LIN consortium.
- In 2010, LIN 2.2A was released and is now one of the most widely implemented versions.
- In 2012, SAE standardized LIN as SAE J2602 based on LIN 2.0.
- In 2016, CAN in automation standardized LIN ISO 17987.
- LIN clusters contain 1 master and up to 16 slave nodes
- Single wire (+ ground) with 1 to 20 kbit/s rate and supports up to a maximum of 40 meters bus length
- Time triggered scheduling with guaranteed latency time
- Variable data length (2, 4, 8 bytes)
- LIN supports error detection, checksums & configuration
- LIN bus operates at a voltage of 12V
- Physical layer specifications are based on ISO 9141 (K-line)
- Supports sleep mode & wakeup support
Difference between CAN and LIN bus protocols
The following table highlights the key differences between CAN bus and LIN bus.
| Parameters | CAN | LIN |
|---|---|---|
| Full form | Controller Area Network | Local Interconnect Network |
| Communication type | Broadcast type | Master-slave |
| Communication network | Multi master, peer to peer | Single master and multiple slaves |
| No. of lines required | 2 wires | 1 wire |
| Maximum communication speed | 1 Mbps | 20 kbps |
| Triggering technique | Event triggered | Time triggered |
| Message length | Longer messages, extensive data payload | Shorter messages, limited data payload |
| Message transmission latency | Depends on message priority | Guaranteed latency |
| Bus conflicts | Uses arbitration process to resolve | No bus conflict |
| Implementation cost | Higher | Comparatively lower |
| Implementation complexity | Higher | Comparatively lower |
| Error handling | Advanced error detection and correction | Basic error handling |
| Electromagnetic interference (EMI) | Resilient to EMI | Less immune to EMI compared to CAN |
| Applications | Safety critical | Non-safety critical |
Conclusion
In summary, from our comparison between CAN vs LIN, we can conclude that CAN and LIN serve different purposes within the same vehicle or industrial system. CAN is intended for high-speed and critical communication, whereas LIN is designed for low-speed and non-critical tasks. They are often used in complementary roles to efficiently handle the diverse communication needs in modern vehicles and industrial systems.
