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Multishot or Oneshot ? and Gyro/PID rate?
#1
Doing some hardware upgrades and have some noob questions on some setting values I am not familiar with on Beta 3

Should I use Multishot or Oneshot125?
And what gyro update frequency I should set?
And PID loop frequency?

I am using
  • TBS 25 bulletproof BL-S ESCs 
  • X Racer FC V3.1
#2
With BLHeli_S you should really use Multishot for best performance, but you will need to run at least 2K looptime in order to run Multishot.
For your gear, you should be able to run 4K/4K and Multishot on safely. You can try even higher but might give you desync, this is probably safer.
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#3
This FC should be run on 4/2khz. It can handle 4/4khz, but that's a bit close to the limit - I had over 50% CPU usage on the bench on BF 3.0 using betaflight pid controller, it flew fine, but I didn't like the feeling that something can go wrong (personal choice).

With those ESCs I'd use multishot. "Just because I can" Wink
Find me on Youtube and Instagram. I currently fly: NOX5, NOX5RAirblade Assault 130 and drive a scrap RC car
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#4
isn't the xracer V3.1 able to run 8k/8k with the latest betaflight? I havn't used mine in a while, but think I remember I was able to run it on 8k/8k on betaflight 2.9.1
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#5
That was probably before betaflight pid controller was introduced.
Find me on Youtube and Instagram. I currently fly: NOX5, NOX5RAirblade Assault 130 and drive a scrap RC car
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#6
With SPI Gyro Bus 8k/8k should be possible, but it depends on the setup i found... one at least one setup I can run at most 8K/4K... CPU just hit the ceiling when I turn looptime up to 8K...
Don't be a LOS'er, be a FPV'er :) -- Blog - Facebook - Instagram - Twitter - Google Plus
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#7
Disable blackbox and other features. F3 can run BF3 8/8 after some optimizations in code which are currently researched.
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#8
I've got a f3 spracing fc and I'm running 4k/4k and cpu is 33% on the bench. is this acceptable.  I don't want to turn off my acc, cuz I'm still newish and I like the stabilization when I come in for landing.  after take off I flip into acro.
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#9
(24-Dec-2016, 08:05 PM)codeblue Wrote: I've got a f3 spracing fc and I'm running 4k/4k and cpu is 33% on the bench. is this acceptable.  I don't want to turn off my acc, cuz I'm still newish and I like the stabilization when I come in for landing.  after take off I flip into acro.

I think the rule of thumb is under 50% cpu utilization should be safe, above that you risk instability (not sure, i'm still new to this hobby).

So you're probably good. I'm running the same, 4k/4k on an spracing f3 and with blackbox and servo tilt enabled I'm at about 40% cpu on the bench and I haven't noticed any problems in flight.
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#10
(03-Feb-2017, 10:39 PM)andrusk Wrote: I think the rule of thumb is under 50% cpu utilization should be safe, above that you risk instability (not sure, i'm still new to this hobby).

So you're probably good. I'm running the same, 4k/4k on an spracing f3 and with blackbox and servo tilt enabled I'm at about 40% cpu on the bench and I haven't noticed any problems in flight.

The SPRacing can't run any faster than 4K/4K due to the gyro is connected with I2C-bus, but the Xracer can run 8K/8K with BF3.1 due to the gyro is connected with SPI-bus.
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#11
(03-Feb-2017, 10:54 PM)oyvinla Wrote: The SPRacing can't run any faster than 4K/4K due to the gyro is connected with I2C-bus, but the Xracer can run 8K/8K with BF3.1 due to the gyro is connected with SPI-bus.

SPRF3 EVO has SPI instead of I2C. Just mentioning to prevent confusion. Wink
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#12
(03-Feb-2017, 10:54 PM)oyvinla Wrote: The SPRacing can't run any faster than 4K/4K due to the gyro is connected with I2C-bus, but the Xracer can run 8K/8K with BF3.1 due to the gyro is connected with SPI-bus.

Good to know; not the topic of my reply to codeblue, and appears to be contradicted by the reply above wrt to the sprf3 evo board, but thanks for the extra info, i'll keep it in mind when I upgrade to betaflight 3.1.
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