DRV Fault

Report your hardware problems here. Include as many details as possible with pictures to get the best possible help and feedback.
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable
benjamin
Site Admin
Posts: 280
Joined: 15 Dec 2015, 08:38
Location: Sweden
Contact:

Re: DRV Fault

Postby benjamin » 24 Jan 2016, 00:44

I'm sorry to hear that it went like that. I understand what you mean, you should see my box with dead PCBs and components... probably more than 100 DRVs...

I had similar behaviour to what you describe with the voltage when my DRV was damaged. It worked when I replaced the DRV, but I thought that this is behaviour very strange. To confirm that it was indeed the DRV that was faulty I put the old one back, and the problem came back. You can try replacing your DRVs and see if it makes any difference. This particular problem did not happen for me often though (maybe two times), so it is strange that you get it on all your PCBs.

arvidb
Posts: 234
Joined: 26 Dec 2015, 14:38
Location: Sweden, Stockholm
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: DRV Fault

Postby arvidb » 25 Jan 2016, 18:57

There's a table in the DRV8302 datasheet, pp. 15, of different fault conditions and the corresponding states of the FAULT and OCTW pins. Did you check the OCTW pin on the DRV8302 during the fault? That could narrow it down a bit. Maybe also check the PWRGD pin?

benjamin
Site Admin
Posts: 280
Joined: 15 Dec 2015, 08:38
Location: Sweden
Contact:

Re: DRV Fault

Postby benjamin » 27 Jan 2016, 09:25

You bemf and current plots look fine as far as I can tell.

Does the motor run again after the drv fault goes away, or do you have to disconnect and reconnect power to the VESC for it to work again? If you don't have to power cycle the fault is not latching (and not reported on OCTW), and there are only three faults in the DRV that behave like that:

PVDD undervoltage, GVDD undervoltage or GVDD undervoltage. I don't think it is PVDD since your battery is not likely to drop under 8V, so it has to be DVDD or GVDD. I've had some problems with GVDD recently, which is supposed to be 12V and used for driving the FET gates. Are you using a 2.2µF capacitor rated for 16V or more for C18? If you are, you can try adding more capacitors there in parallel as I described here:
viewtopic.php?f=5&t=68

Andreas
Posts: 18
Joined: 04 Feb 2016, 19:02
Location: Switzerland
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: DRV Fault

Postby Andreas » 04 Feb 2016, 20:21

If you have fast transients on that GVDD rail, maybe instead of adding more large capacitors, adding a small one would help even more? I'ts kinda hard to see how fast these peaks really are since you are zoomed out way too far.
For my MiniVESC I'll try to keep a small cap (100nF or something) VERY close to that pin, and put the bulk caps (a few µF) as close as the layout allows me.
You could of course try to hack a small SMD cap onto the foot of the IC somehow, and see if that would improve performance, but with a proper layout I guess the inducance is way better and thus the effect of the small cap can not really be matched with a "on the fly" hack, but maybe thats something that helps a bit.

dogeatgod
Posts: 2
Joined: 05 Feb 2016, 12:38
Location: Devon, UK
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: DRV Fault

Postby dogeatgod » 05 Feb 2016, 12:46

When replacing the DRV chip does it require configuring/programming? Sorry if a foolish question
Thanks
Richard

Andreas
Posts: 18
Joined: 04 Feb 2016, 19:02
Location: Switzerland
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: DRV Fault

Postby Andreas » 05 Feb 2016, 20:53


dogeatgod
Posts: 2
Joined: 05 Feb 2016, 12:38
Location: Devon, UK
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: DRV Fault

Postby dogeatgod » 06 Feb 2016, 10:40

Thank you - Andreas


[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Return to “Hardware Problems”

Who is online

Users browsing this forum: No registered users and 3 guests