CAN FD Between PCAN-USB FD and PCAN-USB Pro FD

[pdrexel@delta-q.com]

I am trying to verify the operation of CAN FD using the following setup:

( PCAN-USB FD ) + ( 120 ohm Terminator ) + ( 2 meters 1 pair TIA-568A cable ) + ( 120 ohm Terminator ) + ( PCAN-USB Pro FD Channel 1 )

Both PCANs are running v3.2.0 firmware.
Both PCANs are connected to the same PC via high-speed hub.
Both PCANs are unmodified (i.e., termination not activated)
PCANView version is v5.0.0.814 (64-bit).
OS is Windows 10 Pro 20H2 64-bit.

I can configure both PCANs at 250 Kbps nominal + 2 MBbps data and periodically transmit (T = 200 ms) a 64-byte frame without any errors.
However, if I configure a higher data rate, say 4, 8, 6 or 12 Mbps, the chance of success decreases rapidly. At 8 Mbps, the transmitting PCAN typically goes bus-off on first transmission and the receiving PCAN shows a stuff error and the frame with ESI.

Is this an unreasonable test?
Am I doing something wrong?

[M.Heidemann]

Hello,

Running on bitrates beyond 5Mbit/s will require optimal conditions
in order to work properly.

The higher the bitrate, the more strict the cabling and termination gets.

You also mentioned using a TIA-568A cable, are you sure about that?
That would indicate that you are using RJ-45 connectors
somewhere? Please let us know if that is the case.

Best Regards

Marv

[pdrexel@delta-q.com]

Hi Marv,

I am sure about the cable as it's marked on the jacket and I cut the RJ connectors off both ends and soldered D-9 connectors. The terminators are Peak-System MiniTerm 120 ohm.

Thx,

Pete

[M.Heidemann]

Hello Pete,

I was unaware of your modification to the cable.

Most likely a shorter cable length increase the chances
of getting the aforementioned bitrates to work.

Best Regards

Marvin

[pdrexel@delta-q.com]

Hi Marvin,

I chopped the cable down to ~30 cm, activated the terminators in the PCAN USB dongles and removed the external terminators. 4 Mbps is ok, but 6 Mbps is not reliable. I would love to see Peak's test setup for 12 Mbps. I understand from the website that the FD dongles use the NXP TJA1044GT transceiver. According to NXP's datasheet they are spec'd at 5 Mbps. Perhaps exceeding that limit in all but the most specific/pristine conditions is not possible. I suggest adjusting Peak's advertised specs accordingly.

Thx,

Pete

[M.Heidemann]

Hello Pete,

A good cabling is essential with those higher bitrates,
a shorter cable somewhat mitigates some of the issues but
by default a properly insulated cable will be your best bet.

12 Mbit/s is the maximum we were able to successfully test/confirm here,
which was done under optimal conditions, yes.

We sometimes will have to run higher data-bitrates (beyond 4 Mbit/s)
for support requests and can successfully replicate them here.

So we should be able to get your setup running at 6mbit/s data-bitrate
togehter.

Can you share pictures of your cabling with us and the exact bitrate
configuration that you tried to use?

Best Regards

Marvin

[pdrexel@delta-q.com]

Hi Marvin,

I have attached some pictures.

Bit rate.JPG (74.62 KiB) Viewed 9421 times

Connector.jpg (30.85 KiB) Viewed 9421 times

Cable.jpg (49.05 KiB) Viewed 9421 times

[M.Heidemann]

Hello,

Seems like there is no shielding present. (On our PCAN-Cables Shield is connected to GND)

We recommend to replace the current cable with a cable suited for CAN-bus applications,
especially considering the bitrates you are targeting.

For our PCAN-Cable 1/2 we use cable with the following specs:

PCAN-Cable2_TechnicalData.png (27.71 KiB) Viewed 9404 times

We use either the PCAN-Cable1 or PCAN-Cable2 (Depending on the application) in our daily
support and can run at higher data-bitrates (beyond 4 Mbit/s) without issues.

product-page PCAN-Cable 1 and 2:

https://www.peak-system.com/PCAN-Kabel- ... .html?&L=1

You might want to consider getting one of the aforementioned cables (In your case the PCAN-Cable 1 would be suitable due to
your internal termination being set on your devices).

Best Regards

Marvin

[pdrexel@delta-q.com]

Hi Marvin,

So I ordered and received the IPEK-003000 cable from Phytec ($25 + the same in shipping!) and it's not performing any better than my ethernet pair without a common ground: I cannot reliably transmit a periodic 8-byte message at 4 Mb/s or higher.

Thx,

Pete

[PEAK-Support]

Please, if you think that your CAT cable is usefull for CAN-FD - go on - no one will prevent you from doing so.
Likewise, the shipping costs from x to y of our resellers are not known to us, and actually this is nothing what you should post here in the forum. Here we talk about the technology.

I use the IPEK-003000, 2 x Terminal Blocks IPEK-003002-Mini (the IPEK-003000 cable have NO termination!) and a PCAN-USB FD, connected to the Channel 1 of PCAN-USB Pro FD. I use, Nominal 500K or 1Mbit, Data Rate 1Mb, 2Mb, 4Mb, 6Mb and 8Mb without any problem. So it must be a defectice CAN Transceiver in one of the devices (simply measure the Voltages - see here ) or a not valid physical connection. (no termination ? )
Here some pics with 1Mbit Nominal /10Mb Data using real CAN cable and Termination blocks - busload ~85% ! no problems!

1_10MB_01.JPG (246.22 KiB) Viewed 9274 times

1_10MB_02.JPG (210 KiB) Viewed 9274 times