Having Multiple Signals in one CAN BUS message

[Prince]

Hello, I'm creating a DBC file which will send out several channel values of MoTeC via CAN BUS. The thing I was about to do was to create a message for each signal. But as I looked through the examples, I've realized that irrelevant signals were sent under one message. This is also the case in Motec's "Custom Can Messaging with a DBC file" presentation.

What is the advantage of this method? Does it save bandwith? Should I fit as many signal as possible into one message without exceeding 64 bit CAN BUS limit? What is the difference between this method and multiplexing?

Thank you.

[David Ferguson]

Absolutely, the greatest efficiency (best use of bus bandwidth) comes from packing as much information into each message as possible.

[Stephen Dean]

Multiplexing allows for more data to be sent using the same CAN Addresses (useful if you are limited in the range of addresses that you can use) but at a slower update rate compared to individually addressed packets for each data set.

For example, the PDM Output Current messages are sent as a multiplexed message, this frees up CAN addresses but as there are 5 separate multiplexed message groups in the message, the data is only updated for each channel every fifth message.

[Prince]

Thank you, I will utilize a message as much as possible to not have trouble in the future. I've understood that multiplexing comes into play when even utilizing CAN messages is not enough, then different signals are sent with the same message address sequentially.