27k ohm or 39

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N333M
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Joined: Tue Feb 20, 2018 1:58 am
Location: Hangar at Shelby County Airport (2H0)

27k ohm or 39

Post by N333M »

Working on my EIS 4000 install on 0-320 lyc , standard mags.
Plan is to wire p-leads to tach 1 and tach 2 inputs. Notice both 27k ohm resistors and 39k in package. Instructions mention both, no explanation as to how or why to choose which.
Hmmm. Any help appreciated.
Don
N333M
Don G.
Central Illinois
RV9A 160 hp O-320 carb.
jnewsum1
Posts: 26
Joined: Sun Mar 02, 2014 2:49 am

Re: 27k ohm or 39

Post by jnewsum1 »

The words in the EIS User Manual (Rev L) only mention installing a 27K Ohm resistor between the instrument and the mag P-lead.

I found the info quoted below in the Dynon Skyview install manual about what value resistor to use with the Dynon EMS which might help explain why GRT ships both resistor values in their install kit.

" Six-cylinder Lycoming engines sometimes need more inline resistance to prevent false readings by the EMS. If you supply your own resistors, they need not be exactly 30 kΩ.
Additionally, both 1/4W and 1/2W resistors are acceptable to use. "

I would install the 27K Ohm resistor and keep the 39K in reserve just in case you have an issue with the tach signal later on.
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N333M
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Joined: Tue Feb 20, 2018 1:58 am
Location: Hangar at Shelby County Airport (2H0)

Re: 27k ohm or 39

Post by N333M »

thanks Newsum!
N333M
Don G.
Central Illinois
RV9A 160 hp O-320 carb.
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