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by rew
23 Sep 2017, 20:15
Forum: Custom Applications
Topic: Debugging without compiler optimizations ?
Replies: 2
Views: 218

Re: Debugging without compiler optimizations ?

Chibios is quite complicated. Features like -O2 and "link time optimization" have been available for so long that things are unlikely to be tested and that's when bitrot sets in. And things have started to depend on it. The advice to disable optimizations is a bit oldfashioned. You must re...
by rew
21 Sep 2017, 21:39
Forum: General
Topic: Watt Control Via Duty Cycle Control?
Replies: 14
Views: 1034

Re: Watt Control Via Duty Cycle Control?

20k should be enough.
by rew
21 Sep 2017, 03:31
Forum: General
Topic: BLDC Tool Realtime Data to Excel File
Replies: 4
Views: 425

Re: BLDC Tool Realtime Data to Excel File

Alright, I've resorted to the Arduino datalogger. But, when using the arduino library for reading from the VESC, I found that it takes up about 26% of dynamic memory. So I am going to move from my Nano to a Mega. thee nano is physically small. It has an atmega processor. If you use 26% of memory, t...
by rew
21 Sep 2017, 03:27
Forum: General
Topic: Watt Control Via Duty Cycle Control?
Replies: 14
Views: 1034

Re: Watt Control Via Duty Cycle Control?

Yes some loss of power is a very intuitive signal to the user that the battery is nearing its end.
by rew
21 Sep 2017, 03:23
Forum: General
Topic: [Solved] Wondering about quadrature encoder connection
Replies: 10
Views: 739

Re: Wondering about quadrature encoder connection

Thanks, basically position is calculated by the phase difference between channels A and B (quadrature), and the I is for correction in case of missed-out counts, which shouldnt happen on low-count low-speed encoders while using STM32 arm chips. even it does, i can handle a miss now and then. I'm al...
by rew
21 Sep 2017, 03:22
Forum: General
Topic: [Solved] Wondering about quadrature encoder connection
Replies: 10
Views: 739

Re: Wondering about quadrature encoder connection

Thanks, basically position is calculated by the phase difference between channels A and B (quadrature), and the I is for correction in case of missed-out counts, which shouldnt happen on low-count low-speed encoders while using STM32 arm chips. even it does, i can handle a miss now and then. I'm al...
by rew
18 Sep 2017, 06:24
Forum: VESC Projects
Topic: MiVESC - smaller version of VESC 6
Replies: 6
Views: 1190

Re: MiVESC - smaller version of VESC 6

- I wouldn't be able to sample current while LOW side MOSFETs are not switched on (V0 and V7?). V0 is: "all lowside fets are on". V7 is "all highside fets are on". With shunts in the lowside-to-ground connection you can only sample in V0. With a phase current sense mechanism you...
by rew
18 Sep 2017, 06:19
Forum: FOC
Topic: Motor doesn't spin, only squeaks (FOC with encoder)
Replies: 13
Views: 850

Re: Motor doesn't spin, only squeaks (FOC with encoder)

No, you CAN remove the resistors, but you don't need to. WITH the capacitors the time-constant is 10k * 4.7nF = 47u sec. That's too long. Without the capacitors, the stray capacitance that remains is about 10pF. Your time constant has dropped to 10k * 10pF = 100ns. Short enough. If you are designing...
by rew
18 Sep 2017, 06:14
Forum: General
Topic: Power Limiting instead of Current Limiting
Replies: 25
Views: 1464

Re: Power Limiting instead of Current Limiting

Of course you can control the wattage by adjusting the duty cycle..... In theory. The thing is, your control loop needs to be fast. Having that in the firmware in the mainloop would be best. Slightly more relaxed timing can be obtained by using current control. However, WAY more relaxed timings can ...
by rew
16 Sep 2017, 20:13
Forum: General
Topic: [Solved] Wondering about quadrature encoder connection
Replies: 10
Views: 739

Re: Wondering about quadrature encoder connection

Right! In another thread someone described having replaced the series resistors with 0 ohm ones. Moving from 4.7nF as in the BOM, to "about 10pF" of stray capacitance of the chip pin and PCB you're gaining a factor of 500 over the stock situation. That should be enough.

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