Ask HN: CANBus vs. Ethernet vs. MODBUS

2 points by davismwfl ↗ HN
Environment is moderately noisy, think automotive, marine or light industrial. The requirements are that you need to potentially send the same message to more then one end point. 80% (by volume) of messages are relatively small in nature, say < 100 bytes, a few (< 10%) are as much as 1k in size.

Then say as an option you wanted to add reasonable quality video and still images to the same network occasionally.

Which topology, physical and protocol infrastructure would you think makes the most sense? The field is green so no predisposed environment is defined and it is open to definition.

Appreciate any feedback/input.

2 comments

[ 3.3 ms ] story [ 10.3 ms ] thread
Have you seen this?

http://www.ti.com/lit/an/slyt560/slyt560.pdf

"Conclusion So which interface is best for automotive communications? They all are—but each for its own purpose. The CAN bus reigns supreme for low-speed control applications where cost is a driving factor. When bandwidth requirements move up, Ethernet can step in as an enhanced interface to support moderate bandwidth requirements. When the highest bandwidth and lowest-latency link are required, such as for a surround-view camera system providing input to an autonomous vehicle pilot, then FPD-Link is ready to meet the challenge."

ModbusTCP can be routed over ethernet, as can the video (h.264/h.265). Video over Canbus can be a challenge. Only use modbus, if you already have modbus(TCP) or intend to set up a traditional SCADA system.