Busheavy with terminated bus

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Thomas.TK.Kuhn
Posts: 5
Joined: Wed 12. May 2021, 15:39

Busheavy with terminated bus

Post by Thomas.TK.Kuhn » Wed 12. May 2021, 15:49

Hi,

I am testing a CAN HAT for Raspberry. Connected my PEAK-USB.
I verified that the CAN HAT 120 Ohm is between Pins 2&7.
On the PEAK USB I use a 120 Ohm termination resistor device from VECTOR.
I measure 60 Ohm total between 2&7.
When I send a single message I get BUSHEAVY.
It makes no difference
RASPBERRY
  • Power on
    Power off
    Connected
    Disconnected but terminated with a 2nd terminator
No cable but terminated with 2 terminators.

What's wrong?

M.Heidemann
Sales & Support
Sales & Support
Posts: 673
Joined: Fri 20. Sep 2019, 13:31

Re: Busheavy with terminated bus

Post by M.Heidemann » Wed 12. May 2021, 16:01

Hello,

Please provide us with further information regarding your issue:

Is you connection correct in terms of pin layouts, apart from termination?

Which bitrate-setting is used on your CAN-Hat? (Bitrate, sample point)

Does it match the bitrate-settings used with your PCAN-USB?

Is your CAN-Hat being used as as listen-only node?

Which software do you use with both devices?

Best Regards

Marvin

Thomas.TK.Kuhn
Posts: 5
Joined: Wed 12. May 2021, 15:39

Re: Busheavy with terminated bus

Post by Thomas.TK.Kuhn » Wed 12. May 2021, 19:04

I have a IPEH-002021 S/N <200.000

Just installed the latest drivers and downloaded the latest PCAN View.
I connected a scope bertween 2 &3 and see the following effect:

As soon as I send as single telegram to ID x10 with x01 x02 x03 x04 x05 x06 x07 x08 as data. data is sent infinitly.
If I set the interval to 10.000ms (10s) there is no pause.

A trace looks like that:

1) 1497.5 Tx 0010 8 01 02 03 04 05 06 07 08
2) 1499.1 Warng FFFFFFFF 4 00 00 00 04 BUSLIGHT
3) 1513.4 Warng FFFFFFFF 4 00 00 00 08 BUSHEAVY
4) 95608.3 Tx 0010 8 01 02 03 04 05 06 07 08
5) 95610.1 Warng FFFFFFFF 4 00 00 00 04 BUSLIGHT
6) 95624.4 Warng FFFFFFFF 4 00 00 00 08 BUSHEAVY
7) 163781.6 Tx 0010 8 01 02 03 04 05 06 07 08
8) 163787.8 Warng FFFFFFFF 4 00 00 00 04 BUSLIGHT
9) 163858.7 Warng FFFFFFFF 4 00 00 00 08 BUSHEAVY


When I click on "Zurücksetzen" or hit the <ESC> Button sending of the data stops.

It has nothing to do with the connected or not connected hardware.

M.Heidemann
Sales & Support
Sales & Support
Posts: 673
Joined: Fri 20. Sep 2019, 13:31

Re: Busheavy with terminated bus

Post by M.Heidemann » Fri 14. May 2021, 09:05

Hello,

As of now you have not answered any of the questions i asked you,
as i am trying to assess the issue it would be beneficial to get the information requested.

The information provided only confirms that indeed there is an issue on the bus, that we
need to resolve.

Please try to answer the questions proposed in my last post,
so i have the chance to help you with this.

Best Regards

Marvin

Thomas.TK.Kuhn
Posts: 5
Joined: Wed 12. May 2021, 15:39

Re: Busheavy with terminated bus

Post by Thomas.TK.Kuhn » Fri 14. May 2021, 14:02

Hello,

If you would read my last post thoroughly you would not complain about not answering your questions.

The erraneous behaviour occurs with or without any other bus device except the PCAN-USB.

Anyway here you are:

Is you connection correct in terms of pin layouts, apart from termination?

Pin 2 CAN-L both connectors
Pin 3 CAN-GND both connectors
Pin 7 CAN-H both connectors

Which bitrate-setting is used on your CAN-Hat? (Bitrate, sample point)

The bitrate is set using the following shell command: "sudo ip link set can0 type can bitrate 125000" and is accepted
After the problem popped up the CAN-Hat is disconnected.

Does it match the bitrate-settings used with your PCAN-USB?

Yes

Is your CAN-Hat being used as as listen-only node?

no

Which software do you use with both devices?

CAN-HAT :
Raspbian GNU Linux 10

PC with PEAK-USB
Windows 10 Prof 64-Bit
PCAN_USB.sys 4.2.3.16490
PCAN_Basic.dll 4.5.4.508
PeakCpl.exe 4.4.1.151
PCAN-View 4.3.4.615

The trace file shows that the message is sent only 3 times, but the scope shows that there is massive traffic on the bus. There is nothing connected but the PEAK-USB.

M.Heidemann
Sales & Support
Sales & Support
Posts: 673
Joined: Fri 20. Sep 2019, 13:31

Re: Busheavy with terminated bus

Post by M.Heidemann » Fri 14. May 2021, 14:50

Hello,

Please check if using:

Code: Select all

sudo ip link set can0 type can bitrate 125000 sample-point 0.875
Does resolve the issue, as this is the default sample point used in PCAN-View.

Furthermore, do both devices send and receive CAN-messages?

Best Regards

Marvin

Thomas.TK.Kuhn
Posts: 5
Joined: Wed 12. May 2021, 15:39

Re: Busheavy with terminated bus

Post by Thomas.TK.Kuhn » Fri 14. May 2021, 15:16

Hello,

I have to repeat, the error "BusHeavy" occurs without any device connected to the PEAK-USB.
Only the cable, the terminators and a D-Sub breakout box to connect the scope, are attached to the PEAK-USB.
So only the PEAK USB is sending data
I am sending a telegram with 8 bytes once per second and have repetitive messages on the scope visible.
I will try to make a screen shot of the signal.

So your proposal is welcome, but not targetting the problem.

I am not in the position to read or write data from the CAN-HAT, I am testing the test equipment and see problems there.

Thanks
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G.Lang
Support
Support
Posts: 145
Joined: Wed 22. Sep 2010, 14:58

Re: Busheavy with terminated bus

Post by G.Lang » Fri 14. May 2021, 15:43

Hi,

nothing is wrong, that´s a normal CAN behaviour if there´s no second CAN node available who acknowlegde the transmitted CAN data.

best regards
Gunther

Thomas.TK.Kuhn
Posts: 5
Joined: Wed 12. May 2021, 15:39

Re: Busheavy with terminated bus

Post by Thomas.TK.Kuhn » Fri 14. May 2021, 18:08

Hi,

I connected the board and set the baudrate and samplepoint:

sudo ip link set can0 type can bitrate 125000 sample-point 0.875
AND
sudo ifconfig can0 up

Now it looks ok.

Thanks.
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