FAULT_CODE_UNDER_VOLTAGE

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fotherja
Posts: 6
Joined: 14 Mar 2016, 16:49
Location: Bristol

FAULT_CODE_UNDER_VOLTAGE

Postby fotherja » 14 Mar 2016, 17:17

Hi,

Would really appreciate help with this problem:
I reflowed the VESC and have inspected it very carefully, it looks good. I had no problem uploading the bootloader and firmware to the MCU and I can connect to BLDC tool. I've attached a 2200uF cap close to the board, I've got good bullet connectors going to the motor. Using the default settings, as soon as I try to detect the motor, the motor gives a little jerk, then another ~5seconds later before showing a "Bad detection result received" on BLDC tool. I've tried all sorts of detect parameters. I'm using hobbyking's largest 149Kv outrunner, but the same happens with another motor I've tried. I'm powering the system with a 5A 20v power supply.

I've built a VESC before which worked fine. Using the BLDC parameters from then, I can get the motor to spin ok which seems to prove the front end is working. But FOC detection etc isn't working and I wanted to use a different motor etc. It's really really frustrating me so please help.


Fault : FAULT_CODE_UNDER_VOLTAGE
Current : -70.3
Current filtered : -69.5
Voltage : 7.36
Duty : 0.69
RPM : 1088.6
Tacho : 11
Cycles running : 422
TIM duty : 4061
TIM val samp : 2040
TIM current samp : 4993
TIM top : 5906
Comm step : 5
Temperature : 24.10

Best wishes,
James

david
Posts: 36
Joined: 15 Dec 2015, 13:19
Location: Hamburg, Germany
Contact:

Re: FAULT_CODE_UNDER_VOLTAGE

Postby david » 14 Mar 2016, 18:06

Did you check this?
viewtopic.php?f=5&t=68
VESCs made in Germany http://www.esk8.de

fotherja
Posts: 6
Joined: 14 Mar 2016, 16:49
Location: Bristol

Re: FAULT_CODE_UNDER_VOLTAGE

Postby fotherja » 14 Mar 2016, 18:25

I just added that 2.2uF cap for good measure but it hasn't solved the problem at all. That shouldn't be a problem with BLDC detection anyway. With the fault readout i've included, is it normal for the currents to be as large as that?

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

Re: FAULT_CODE_UNDER_VOLTAGE

Postby benjamin » 14 Mar 2016, 20:40

I think you have some problems with current measurement. Make sure that everything between the shunts and mcu is soldered properly.

fotherja
Posts: 6
Joined: 14 Mar 2016, 16:49
Location: Bristol

Re: FAULT_CODE_UNDER_VOLTAGE

Postby fotherja » 15 Mar 2016, 14:57

Thank you so much Benjamin!! You we're spot on. With close inspection and use of a continuity meter I found that one of the sense legs on a shunt resistor wasn't quite making contact with it's pad. Soldering it has fixed the problem and it works brilliantly.

I'm so grateful.


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