RPM pulses

[cjhukill]

I am trying to configure my EMS for my Lyc IO540 with dual slick mags. I am using pins 32 and 33 with the supplied resistors from the P leads as described in the manual. I need to enter the RPM pulse configuration but I am unable to find that information. The manual directs me to "http://downloads.dynonavionics.com." which doesn't seem to exist, as it keeps opening to the "http://www.dynonavionics.com/docs/support_software_choice.html" page.
Searching this forum hasn't provided the answers either. Can someone help?

 

[Dynon]

It should be 1.5. If that's looking absurdly (about doubly) high, then double it to 3.

 

[paul330]

I'm just setting up my IO-540 with mags and the RPM sensing the P-lead with in-line resistor. I know that the pulses per rev needs to be set and how to do it, but why would it be 1.5? Surely there are 3 firings per rev (6 per two revs) - n'est pas?

 

[dynonsupport]

The polarity of most magnetos alternate each pulse, and we can only sense positive pulses. Thus, we only see every other one.

 

[paul330]

OK. So I set to 1.5 and it worked fine. Just for info on an IO-540, I used a 30k resistor on the left P-lead and 60k on the right to see what worked better for the RPM- both were rock steady.

 

[paul330]

Further to this, I may have been a bit premature saying it was "Rock Steady". I ended up fitting a 60k to each mag which was fine right up until the very top end (above 2600) when it went unstable.

I guess the fix is to increase the resistance to (say) 100k?

 

[jakej]

For a better,more reliable, option for the IO-540 as they can suffer from some rpm instability more so than the 4 cyl would be to use these IMO http://store.makerplane.org/magneto-p-lead-tachometer-signal-stabilizer-p-tach/

Jake J

 

[vlittle]

Corrected link http://store.makerplane.org/magneto-p-lead-tachometer-signal-stabilizer-p-tach/
Datasheet is available under the documents tab here: http://54.162.78.90/redmine/projects/p-tach



Vern

 

[paul330]

150k did it.......