1 Topic by Canny01

  • Canny01
  • Новичок
  • Offline
  • Registered: 17-02-2024
  • Posts: 7

Topic: can message missing several times when reading can bus

Hello,

For a project i am reading several extended can bus messages from the can bus. One of the messages is broadcasted each 400ms.
This is quite a slow interval and now it seems that the canny 7.0 is sometimes missing this message. This results in a delay in switching due to the missing message from some times 1.2 or 1.6 seconds. (3 or 4 messages missing before detecting the message).

Other messages that i am looking for are broadcasted with a higher frequency of 30 ms and aren't a problem.
I also noticed when i am removing reading these messages from the program (only reading the 400ms messages)  it improves the program and the 400 ms second messages doesn't seems to be missed any more by the controller.

In the  attached file you will find the program.

1. Why is the canny logic 7.0 missing several of the 400ms messages ?
2. How can we improve the program so we don't miss anny of the 400 ms messages ?

2 Reply by Konstantin, CANNY logic

  • Konstantin, CANNY logic
  • Konstantin, CANNY logic
  • Administrator
  • Offline
  • Registered: 19-02-2013
  • Posts: 199

Re: can message missing several times when reading can bus

What is your CAN bus utilization rate (total messages with any IDs per second)?
With no CAN filtering enabled, your CANNY 7 try to catch every message with every ID and can be overflowed if the CAN bus utilization is high. If this happens, you can get a "1" in the "CAN Overflow Register".
Try to use the CAN filtering https://cannylogic.com/docs/c7/can/#sec … ample-ex_3

Konstantin, CANNY logic's Website

3 Reply by Canny01

  • Canny01
  • Новичок
  • Offline
  • Registered: 17-02-2024
  • Posts: 7

Re: can message missing several times when reading can bus

Hi Konstantin,

The can baud rate is at 500kb/sec and there are aprox. 2800 message a sec.

I will try to use the filtering and let you know the result.

4 Reply by jackmarvia689

  • jackmarvia689
  • Новичок
  • Offline
  • Registered: 29-06-2024
  • Posts: 1

Re: can message missing several times when reading can bus

possible reasons

High CAN bus traffic might cause delays or message loss. or Other higher priority messages might interrupt receiving the 400ms message.

5 Reply by Canny01

  • Canny01
  • Новичок
  • Offline
  • Registered: 17-02-2024
  • Posts: 7

Re: can message missing several times when reading can bus

Hello Konstatin,

As you recommended Can filtering solves the issue.

Thanks