Re: [Linuxptp-users] Integration with simulink real time

[<eli...@ta...>]

Hi,


An update possibly useful for people in the future.

Mathworks eventually found that the issue was entirely a bug within their matlab/simulink code. It seems that they were improperly associating timestamps and PTP packets causing instability in their  PTP algorithm. It is an issue that is unique to situations where their code is acting as a slave and not a master, or with more than one slave on the network.


Eliot.

________________________________
From: Eliot Dixon (TMETC Plc)
Sent: 27 April 2018 08:26:26
To: Richard Cochran
Cc: lin...@li...
Subject: Re: [Linuxptp-users] Integration with simulink real time


Hi,


Thanks for being interested in the problem.


I call it a real-time machine as it is running Simulink Real-Time OS to allow Simulink models to run in real time, but as far as I know this is actually based on FreeDOS.

I'm not actually were what software it is running as its all a bit black-boxed and wrapped up in simulink code.


After poking around a bit in wireshark, I suspect that the its a problem with how simulink is synchronising the clocks and is probably only solvable by them. The messages being exchanged across the network look correct to me, at least compared to what is being swapped between the linux machines.


Thanks,

Eliot.

________________________________
From: Richard Cochran <ric...@gm...>
Sent: 27 April 2018 06:30:27
To: Eliot Dixon (TMETC Plc)
Cc: lin...@li...
Subject: Re: [Linuxptp-users] Integration with simulink real time

On Thu, Apr 26, 2018 at 03:36:52PM +0000, eli...@ta... wrote:
> Essentially, the problem is that between my linux machines
> everything runs perfectly, but on the realtime machine the PTP time
> varies wildly (several years wildly) without converging on an
> answer.

What OS is running on the "realtime machine", and what is the PTP
software stack?

Thanks,
Richard
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