• Influx Technology

Baud rate

What is the Baud rate?

The rate at which the information is transferred in a communication channel is known as the baud rate. Or, more generally, the baud rate is the speed/rate at which the data is transmitted on the network. This is expressed in bits per second. Hence the number of bits that travel on a communication network in a second is the baud rate.

For a CAN bus, which is a serial, multi-master bus, if the baud rate is mentioned as “500000 baud”, that port on CAN can transfer a maximum of 500000 bits per second.

Different Baud-rates supported on CANbus:

· 125 kbps

· 250 kbps

· 500 kbps (Standard for most automotive applications)

· 1000 kbps (1mbps)

Various software allows the user to set the bus speed depending upon the need of the CANbus. The below image is from Influx’s DiaLog software, enabling the user to select the bus speed (from various available options).

How many messages does every baud rate support?

CANbus supports the transmission of data that can be 8 Byte long. But, the transmission of such long messages results in larger latency. At a bit rate of about 1 Mbit/s, with an average data length of 4 bytes, up to 10,000 messages per second can be transmitted using a standard format, i.e., with 8 bytes data length, up to 7,200 messages can be sent per second.

Using simple formulas, one can calculate the approx—time to transfer one frame on the CAN bus.