Seamless Fractional Prime Cut

Discussion and support for MoTeC's previous generation ECUs.

Seamless Fractional Prime Cut

Postby Ben-S on Fri Sep 26, 2008 12:40 am

I have always wondered exactly what the RPM limit randomiser was and am now even more curious with the addition of "seamless fractional prime cut". Can someone explain exactly what these numbers are describing or how a cut sequence is determined based on the value for this channel?

Thanks in advance
Ben-S
 
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Re: Seamless Fractional Prime Cut

Postby RossB on Fri Sep 26, 2008 2:43 pm

The Randomiser number determines the cylinder cut sequence of the RPM Limiter based on the cut level and the Randomiser number. It works as follows:
Cut_new = (Cut_old + randomiser)%256
Cut current cylinder if ((cut_level*256/100)>cut_new)
cut_level = (RPM-RPM limit)*100/CTRL_range
Cut_new is updated at each TDC

Cut_level is only calculated when RPM > RPM_limit otherwise it is 0

The attached spread sheet shows a visualisation of a few examples.

The Seamless Fractional Prime Cut is an alternative which may work better on engines with small number of cylinders, at low cut levels it will avoid consecutive cut to the same cylinder.
Attachments
MoTeC Randomiser visualised.xls
Randomiser visualisation
(117 KiB) Downloaded 1941 times
RossB
 
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Re: Seamless Fractional Prime Cut

Postby Ben-S on Sat Sep 27, 2008 2:40 am

Thanks Ross, good to know whats going on in the background
Ben-S
 
Posts: 134
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