Re: CAN bus real-time sender and precise timestamp receiver tool

Hello David

I usually do this with two CAN-USB interfaces. Because the timestamp
is generated in the interface, not on the PC they are generally very
good as long as you don't compare the timestamps of two different
interface that have not been synced.

So you send on one interface, then you receive both the sent message
and the answer from the tested device on the other CAN-USB interface.

That way both the sent message and the reply are timestamped on the
same CAN-USB device, independent of the PC, so they are usually comparable
with at least millisecond precision even on entry level CAN-USB interfaces.

This also removes the risk that the tx timestamp and rx timestamp may
have different errors on entry level CAN-USB interfaces. Because you use
the RX timestamp to record both the sent and received message if there's
a fixed error, like from delays in the firmware of the CAN-USB device, these
will have no impact on the measurment as both timestamps will have the
same the same error.

The important thing is to make sure that your CAN-USB device generates the
timestamp in the firmware, that it's not generated by your CAN analyzing
software on the PC.

Simon

Simon Byholm - Software Manager / Quality Manager

Phone: +358 6 357 6306
Fax: +358 6 357 6320
email: [email protected]
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TK Engineering solves your CAN, CANopen, J1939 and NMEA2000 problems by providing the hardware, software and know-how you need to design, manufacture and troubleshoot your industrial and heavy machine CAN networks. Call +358 6 357 6300 or email [email protected] to learn how we can help you solve your CAN related problems.

On 11.9.2015 12:29, [email protected] wrote:
> Hello
>
> For one of our equipment, we need to realize performance test over the CAN bus :
>   - we want to send CAN messages at a frequency of 100Hz with a precision of 1ms to the equipment,
>   - and also, to timestamp received CAN messages from the equipment at a precision of 1ms.
>
> We aren't able to do this with a "classic" USB-2-CAN interface because of the latency of the PC.
>
> Would you have any solution ?
>
> --
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