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FAULT_CODE_ABS_OVER_CURRENT on custom pcb

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TVAVAE
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FAULT_CODE_ABS_OVER_CURRENT on custom pcb

Hi all, we made a pcb, first time it worked great. We added the start circuit and redid a part of the layout and the vesc stopped working. Really strange, but we get a FAULT_CODE_ABS_OVER_CURRENT while doing the Foc setup. Can someone help us with this? 

vadicus
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If it worked in the previous layout and the only thing you changed is the layout, then the layout must be the most likely issue. I'd guess noise get injected in current sensing circuit. You can post your FOC graphs when the fault is triggered as well as response from the Faults command in the terminal. That may provide a bit more clue.

TVAVAE
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Not getting notifications here, but it aint noise we think. Can we maybe video call some time? We did alot of tests the past weeks and nothing solves the issue, made 3 hardware runs, 1st one was good, 2nd was based on the latest schematics, and started resonating, 3th we started from the 1st design with the latest schematics, trying top keep all routing as simular as possible, but again the same  issue.

We can show the fault (abs over current) with scope measurements and more of useful, but we cannot get past the Foc calibration, so not sure that to share there?

eguven
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Hello,  I have the same issue.  I am using  200u Ohm shunts and INA240 Shunt amplifiers. When the VESC is idle,  I see 1.65V at the output of the  INA240, which is expected.  Vesc interprets this to, a current between -2 /2 Ampere flickering which is acceptible. Once I start the motor,  there is a huge spike on the out put of the INA240  measured with scope exceeding 3.3v, and the  sampled data reports  phase  current reaches up 800A ,

I believe I might be missing something on the implementation of INA240, If you share your experiences  it would be really appreciated 

eguven

eguven
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Here you can find my scope output.

There are number of strange things in place

1- All the phases are triggered at the same time.  the  Ch-1 Ch2 Ch3 of the scope is showing the phase voltages. I broughed them to the same refernce point, then it is obvious that there is a  overlap. I would expect there phase shift between them.

2- I have removed the motor during this test.  So the green graph at the bottom Ch-4 is the attached to the shunt on the  1st phase. I can see spikes on the shunt,  but the average curent is almost "0" which is expected since there is not load. However  when I check the sampled data, as belowsampled data.png

I can see  current sensing around 100 A. I think the reason is the  current spikes occurring on the shunts when the mosfets are switching.  One possible solution could be to eliminate those spikes with a low pass filter between the shunt and opamps. 

Any recommendantion for the filter to be applied ? 

eguven

eguven
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scope output.png

eguven

skyline1970
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gain of INA240 type?

if input filtering had been applied, r and c values?

eguven
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It is INA240A1D  gain : 20 V/V, there is no input filtering applied.  Any recommendation for the filter architecture and R anc C values  ?  

eguven

skyline1970
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r= 2 x 10ohm, c=1.. 10nf

just a look on datasheet