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Offline ftec

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Buffer Error
« on: October 08, 2010, 12:49:34 PM »
Quite suddenly I'm getting mysterious External Stop Requests. The LastErrors.txt informs that External Stop was requested and that the command was killed due to *buffer error*. Can anyone tell me to what the 'buffer error' is referring to? If I actually press the E-stop button no mention about buffer errors.

The only things that can cause external stop requests from the cabinet to Mach are if one of the servos is overloaded or if the E-stop button is pressed. None of this is happening and the servos are OK after the incident. The other thing is that this only happens in Y direction and only when the spindle is running. The axis moves a couple of mm and then stops as well as the spindle stops.  I've also had some M3 scripting errors which may have something to do with this but never really paid much attention to those as everything seemed to work fine otherwise.

Anyone able to help me with this one?

Thanks
/Risto

PS. I used the Mach .038 version and updated to .040 but no improvement.
« Last Edit: October 08, 2010, 12:51:44 PM by ftec »

Offline ftec

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Re: Buffer Error
« Reply #1 on: October 08, 2010, 02:16:50 PM »
Ended up changing a spare MB, no help. If I turn off the spindle power but use the M3 as normally no errors. The conclution is that once again it is the C11 doing tricks as it has since the beginning.

Offline Hood

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Re: Buffer Error
« Reply #2 on: October 08, 2010, 02:28:21 PM »
Could it be noise from the spindle that is causing issues?
Hood

Offline ftec

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Re: Buffer Error
« Reply #3 on: October 08, 2010, 02:42:31 PM »
Thanks Hood but no, all cables are high quality shielded robotics cables and the machine has been working perfectly for months.  I'm now almost sure that it is the C11 BOB. It had voltage 0V level issues when I bought it and which I had to fix with additional pull down resistors, will check it in the morning.
« Last Edit: October 08, 2010, 02:53:06 PM by ftec »

Offline Hood

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Re: Buffer Error
« Reply #4 on: October 08, 2010, 02:53:17 PM »
Kind of sounds that way.
Hood

Offline ftec

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Re: Buffer Error
« Reply #5 on: October 09, 2010, 11:11:41 AM »
The reason was the C11 cards Safety Charge pump and its pin 17. I've had three of these cards changed for warranty because all of them had the same problem which was/is that the logic low was/is too high 0.7V to drive TTL logic chips. Finally it was pulled low with an external 300 ohm resistor. Now, in the course of time it makes the high voltage too low. The safety circuitry is enabled by the C11 Charge Pump pin 17 and what happened was that safety circuitry started to oscillated and oscillated the VSD-A servo drives disable input every time the spindle was turned on. The problem is not yet fixed as it should, the SC pump is now bypassed for the time being and everything is back to normal.

/Risto

Offline Hood

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Re: Buffer Error
« Reply #6 on: October 09, 2010, 08:01:07 PM »
Thanks for the update.
Hood

Offline ftec

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Re: Buffer Error
« Reply #7 on: October 10, 2010, 04:22:09 AM »
I've had so much trouble with this particular BOB from the beginning that I hope my explanation may help someone else. The specs promise TTL level compatibility but that was not the case with my version 9.3 of the card. Some have posted me privately telling about their similar problems. When you build a machine with tons of things which may go wrong it is helpful to be aware of what others have experienced and that everything is not always your own fault.

A correction to what I said about the warranty. I sent one faulty one back to the manufacturer who sent me a replacement but that had the same fault. I made and showed them pics of the measurements of the fault, even measured things they asked me to measure and after that they sent me a third card for free but that had the same fault too.

/Risto