To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Message-Id: <AA-A706B213C3E94529081F944BE2A96603-ZZ@www4.prodigy.net>
Date: Tue, 05 Aug 2003 14:25:03 -0500
From: DELTAFLYER@prodigy.net
Subject: Re: [FlyRotary] Re: Tach Divider

David,
Just recently resolved my RMI tach issues so I think I 
can provide some guidance. I drive the RMI tach from 
the yellow wire off the Mazda coils. This provides a 
12volt 2ms duration pulse twice per revolution.
Configure the RMI as for a 4 cylinder engine.
Using a pulse generator on the bench I found that if 
the signal went below about 10volts the tach would 
stop working. The RMI tach only worked up to 4500RPM 
and then would read half the RPM's above 4500. This is 
due to a one-shot circuit that Ron has built in to 
suppress spurious glitches from getting through.
Unfortunately it is set up with too low an R/C time 
constant for our use. However it can be fixed with a 
simple resistor change. If you would like more info on 
this fix feel free to contact me off line or contact 
Ron at RMI as I have recently.
Jim Maher
Dyke Delta/13B

--- Original Message ---
From: "David Leonard" <Daveleonard@cox.net>
To: "Rotary motors in aircraft" 
<flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Tach Divider

>This brings up a good point that I have been meaning 
to ask - esp.
>Tracy.  I wired my CAS the EC2 as instructed, but I 
also wired one of
>the leads in parallel with the hall sensor on my 
Rocky Mountain Engine
>Monitor.  Does anyone think that this will not work?  
I'm not really
>sure how the hall sensor worked, but I figured the 
motion of the magnet
>created a small voltage spike in the circ.  I figured 
the spike would be
>big enough to trigger 2 voltage sensors (one in the 
EC2 and one in the
>RMS Monitor) at the same time without causing any 
problem.  This will be
>one of the things I look at if all does not work well 
at fist start, but
>does anyone know for sure this will not work?
>
> 
>
>Thanks,
>
> 
>
>David Leonard
>