Wireless CAN (Controller Area Network)

The CAN (Controller Area Network) serial protocol was originally designed to be used for communication between sensors and computers in automotive applications. Since its inception it has grown to be used in a number of different commercial and industrial applications.

A number of different data rates are defined, with 1Mbps being the top end, and 10kbps the minimum rate. All CAN compatible units must be able to support 20kbps.

The CAN Bus interface uses an asynchronous transmission scheme controlled by start and stop bits at the beginning and end of each character and Non Return to Zero (NRZ) encoding over a twisted shielded wire pair.

Using CAN with Digi radios

Digi RF radios are designed primarily for low data rate, long range communication. All Digi radios are designed with a serial interface that typically can operate from 1200 - 115200 and varying over-the-air data rate depending on the radio. The radios use a standard UART interface that is not directly compatible with CAN because of the slower speed and the physical difference between CAN and a TTL/CMOS level or RS-232 level UART.

There are a number of different converters on the market that will convert between CAN and RS-232. Digi has had a number of different customers who have deployed wireless CAN systems using Digi's stand-alone RS-232 radios in conjunction with CAN to RS-232 converters. Generally, the data rate ends up being lower in these types of systems, but if small amounts of data are sent and the timing is not critical, then radios can work well in wireless CAN systems.