FEDEVEL
Platform forum

, 06-19-2024, 06:47 PM

Hi everyone,
I am planning to develop an AMR (electric robot) that has few electronics boards, drive controllers and other peripherals. So, please suggest which should be used in this between CAN and power Ethernet. If anyone supports documents please share with me.

Further I recently saw an internet sharing adapter (Mercusys Tp-Link Mp500 Kit Av1000 Gigabit Powerline Starter Kit ) through a single phase ac line. Can I send the same thing through DC supply. Does anyone know what circuit was there behind that Av1000 gigabit adapter. Please share if there are any reference documents.

Thanks in advance.

QDrives , 06-19-2024, 07:09 PM

What do you want to do and what do you need?
How much data do you need to transfer and how reliable / deterministic must that be?
Do you need communication over power lines?
How many connections?
How many devices?
Length/distance between them?

, 06-20-2024, 02:41 AM

My architecture is like this,
Main board which will disturb power to all other boards and should get feedback from those boards over CAN or POE. I also have a motor controller to drive the motors over CAN or POE.
500kbps data Max can transfer overall the boards and controllers.
The communication and connection should be more reliable and effective.
Max 15 connections and 9 devices and everything is within 1.5m.
I am not sure how reliable and possibility communication over power lines is.
Can you suggest which one is the best one in between them (CAN or POE).

QDrives , 06-20-2024, 04:02 PM

CANbus it deterministic, that means that the high priority messages get transmitted first. Ethernet does not have that.
CAN is must easier for embedded systems than ethernet is.
If you use CANopen as protocol, you can communicate with many external products too.

, 06-20-2024, 04:31 PM

Agreed but with POE we can send data and power in a single cable up to 100Watts right and also encrypted.

QDrives , 06-20-2024, 04:33 PM

1) Makes it more complicated
2) Do you need encryption?

, 06-20-2024, 04:56 PM

Yes, now a days POE is more comman right. How that is more complicated?
Also if any CAN node got shorted then everything will not work until clear that one.

Robert Feranec , 06-21-2024, 06:31 AM

I would like to point out, the proper POE can be expensive - in some designs we used some of the wires in ethernet cable to distribute power. In your case I would consider CAN as implementing Ethernet for every single module may be overcomplicated and also, CAN has some advantages over Ethernet in control environment (priorities, one message to more boards, canceling messages, etc ...). I would recommend to watch my video here: https://youtu.be/OqN7xNn92pc

QDrives , 06-21-2024, 07:39 PM

POE is common for you as consumer. However, not so common for design. Especially, like Robert mentions, to do it properly.
True, if you short the CANbus there is no communication. Just as shorting the power to the ethernet switch does.
Do note that if shorting the bus is your concern, think of the millions (rather billions) of devices are using it reliable (every modern car!)

Ken Tindell talks about the J1939 protocol. That is big in automotive, but little used in industry.