Automotive and process control
environments aren't the only
homes for controller-area networking (CAN) these days. It can be found in everything from printers to robots.
Topping out at 1 MHz, CAN uses a differential bus architecture (Fig. 1). Its packet
data size is only 8 bytes, but this is often
more than enough for embedded applications. In fact, the identifier is frequently used
to indicate an event or value when there are
no data bytes. Multiple packets can be used
to transmit blocks larger than 8 bytes.
The key to CAN is the transceiver (Fig. 2). It's typically implemented using bipolar
technology to handle 12-kV ESD and provide thermal, short-circuit, and transient protection. This robustness can be quite useful in
non-automotive environments as well.
Protocols have been built on CAN, including CANOpen. Supported by CAN in Automation (CiA), CANOpen's device profiles describe how a node operates. It also lets designers build
their own nodes that work with nodes from different vendors.
The CANOpen protocol is much simpler than TCP/IP, but it's ideal for
sensor and control applications. It might be
the right protocol for your next project.
CiA
www.can-cia.org
See Associated Table