I'm hesitant to ask this but...  any chance you have a USB connected 
device that is either not plugged in entirely, intermittent or flaky?

Some systems seem to take a time out when a USB device goes on or offline.

Dave

On 5/19/2013 10:19 AM, Maximilian H wrote:
> Hello Everybody,
>
> many thanks for your great input. It has given me some ideas of what I
> can try next.
>
> As we have a holiday on Monday I will not be in the shop until Tuesday.
> I have a ssh connection to the machine, but since I started this thread
> the machine has been running linuxcnc with the 7i43+7i33+interface pcb
> without any problems in the lab again. The current load of the machine (
> uptime/top ) is about 6, and I still have a working realtime for almost
> two days now.
>
> Summarizing all replies, ideas, questions.
>
> 1. Ntp/network is a good idea, since I do have this setup via cron to
> check the time every 20 minutes. However, these ntp updates happen also
> in the lab, and there I don't get any watchdog bite. Anyway I'll disable
> the ntp updates and see what happens.
>
> 2. Yes, I should have saved the output of dmesg. I checked it, but did
> not save it. There was no "unexpected realtime delay" message, that I do
> remember. I will save dmesg's output next time.
>
> 3. I am running a 1ms servo loop on two other linuxcnc machines with
> 7i43+7i33. A 1ms servo loop only works for me with onboard lpt ports. I
> had no such luck with pci boards. I must say that I have never checked
> with pci-e cards. When building a pc for use with linuxcnc I just always
> make sure to have an onboard lpt port for the epp communication. This a
> dual core machine at 3GHz that I am using, so there is enough cpu power
> to spare, even if one core is busy with the servo loop.
> And after Friday's email to the list, the last thing I tried was running
> with a 5ms servo loop and the watchdog did bite again.
>
> 4. Monitoring the epp communication with a digital scope would be an
> option, I don't have one myself, but I know somebody how does. Certainly
> it would make sense to see if the communication really breaks down for
> over 500ms. But I know nobody who owns a logic analyzer, so I can only
> check 2 chan max. What pins on the ribbon cable are the most interesting ?
>
> 5. EMI certainly/unfortunately is a possibility. The ribbon cable from
> the pc to the 7i43 is short, about 30cm, but who knows what kind of EMI
> I do have in a 30y old mill. And of course the ribbon cable is not
> shieled either. I tried running with the converter for the spindle
> powered down, but that did not help either.
>
> 6. The 7i43's watchdog timeout I first had set to 5ms, then 100ms and
> increased that value to a final value of 500ms. And still I got watchdog
> bites at a timeout of 500ms without any unexpected realtime delay
> message. Of course, once the watchdog bites, I get following errors too
> since the axes don't move anymore once the watchdog has bitten.
>
> 7. I will try to decrease vm swappiness from 60 (ubuntu's default) to
> 10. The machine has 4Gb ram of which only 3,5 are useable because of the
> 32bit architecture. The linuxcnc pc never runs anything except linuxcnc,
> so it should never swap anyway.
>
> 8. External events. I could use the 7i43's hm2_7i43.0.watchdog.has_bit
> pin as a trigger for halscope, but what other events should I monitor in
> halscope ? Halscope can only monitor a maximum of 8 channel, I believe.
> Or does somebody have an working example of a streamer/halstreamer setup
> that I could copy. Anyway, what other values from hal space would be
> interesting to debug this ? Ferror, cmd pos, fb pos, velocities, accel
> for all axes, pwm values, the watchdog has-bit pin, the io_error pin,
> and what else ?
>
> 9. Question. Since I don't have an io_error
>      16  bit   RW          FALSE  hm2_7i43.0.io_error
> and the documentation at
> http://linuxcnc.org/docs/html/man/man9/hm2_7i43.9.html tells me that the
> io_error should be set if I do have a broken epp communication, does
> that mean that I can rule out EMI on the cable from the lpt port to the
> 7i43 ?
>
> 10. I could buy a pcie lpt port and see if that helps.
>
> 11. Video drivers are vesa, no nvidia hardware. No flash, no firefox,
> nothing but the linuxcnc ubuntu 10.04 32bits and the cnc software running.
>
> 12. Did I forget something else that I could check ?
>
> BR
> Max.
>
>
>
>
>
>
>
>
>
>
>
>
>    
>> On Fri, 17 May 2013, Sebastian Kuzminsky wrote:
>>
>>      
>>> Date: Fri, 17 May 2013 15:33:05 -0400
>>> From: Sebastian Kuzminsky<[email protected]>
>>> To: "Enhanced Machine Controller (EMC)"<[email protected]>
>>> Subject: Re: [Emc-users] 7i43 watchdog has bitten, looking for the cause ?
>>>
>>> On 05/17/2013 03:27 PM, Andrew wrote:
>>>        
>>>> 2013/5/17 Maximilian H<[email protected]>
>>>>
>>>>          
>>>>>    I use a
>>>>> servo loop of one millisecond.
>>>>>
>>>>>            
>>>> I'd say 1ms is too short for 7i43, at least it never worked for me. Try
>>>> increasing it to 4ms to eliminate the possible cause.
>>>>          
>>> I've run a 7i43 at 1 kHz, "it worked fine for me".  I guess it would
>>> depend on the user's hardware how well it works.
>>>
>>> Maximilian reported that after a watchdog bit, the max time taken by the
>>> servo thread was 765 us:
>>>
>>>        
>>>> Realtime Threads:
>>>>       Period  FP     Name               (     Time, Max-Time )
>>>>       498550  YES          servo-thread (     6060,   764883 )
>>>>          
>>> ... so a 1 ms servo period doesn't seem to be the problem here.
>>>
>>>
>>> -- 
>>> Sebastian Kuzminsky
>>>        
>>
>>
>> Another possibility that Sebastian hinted at is that there's an electrical
>> noise problem. This could cause a false reading that indicates a watchdog
>> timeout even though one has not happened (though you would expect many
>> readings to be corrupted in this case not just watchdog state)
>>
>>
>> Peter Wallace
>> Mesa Electronics
>>
>> (\__/)
>> (='.'=) This is Bunny. Copy and paste bunny into your
>> (")_(") signature to help him gain world domination.
>>
>>
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>
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