ADC Alt CAM, Alt CRANK RC filter

maximus64 · Post by **maximus64** » Wed Apr 11, 2018 5:01 pm

On Frankenso schematic, ADC section for ALT CAM and ALT CRANK have a label that said "low pass filter knee at 100kHz typical". Is the 10K before the diode clamp take into account? I don't think it correct, base on my calculation it should have a cutoff at around 1.5kHz not 100KHz. Is this too much filtering for trigger input? I'm using this input for NA8 Miata CAS input.

kb1gtt · Post by **kb1gtt** » Wed Apr 11, 2018 5:08 pm

The LPF is only for R313 and C310, filtering caused by external caps, and the influence of R312 are not included in that schematic note.

Required frequency is dependent on your crank wheel. More teeth needs more Hz, as well faster RPM's needs more Hz.

Post by **AndreyB** » Thu Apr 12, 2018 7:46 pm

I am not sure if any miata runs on op-amps

RadMx5 · Post by **RadMx5** » Sat Apr 14, 2018 8:17 am

My does work on op-amps

Both Cam and Crank

Just having some issues above 6500RPM. I have still not found the source of the problem. It could be to do with filtering as you say "maximus64"

For now I'm waiting for another engine... As my current engine started to burn oil...

maximus64 - if you want there is some info here: https://rusefi.com/forum/viewtopic.php?f=3&t=1282

rusefi.com

[help needed] ADC Alt CAM, Alt CRANK RC filter

ADC Alt CAM, Alt CRANK RC filter

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Re: ADC Alt CAM, Alt CRANK RC filter