Re: uMonitor and Plasma III Tach Pulse

Dave Adams

This is for the archives for those of us Neanderthals still using the uMonitor.  After connecting the Plasma III tach output signal directly to the uMonitor tach input, I did some testing.  I removed the original R3 (that I had installed over 30 years ago!).  I temporarily replaced R3 with a 10K ohm potentiometer for testing.  After starting the engine, I slowly turned the pot, lowering the resistance.  At 6.3K ohms, the uMonitor tach started working and provided a steady RPM signal.


I decided to somewhat split the difference between what Ron Mowrer had stated would be acceptable (about 3K ohms), and what I had found to work with the 10V output from the Plasma III.  I installed a 4.7K ohm resistor for the new R3.  I tested it this evening and it worked fine.  There is no need for a capacitor between the Plasma III and the uMonitor input.


Dave Adams

Long EZ N83DT

Race 83


From: canard-aviators@... [mailto:canard-aviators@...]
Sent: Tuesday, June 18, 2019 9:59 AM
To: canard-aviators
Subject: Re: [c-a] uMonitor and Plasma III Tach Pulse





Just found the document (Same one as Nick provided) and recall doing this for a client.  You may have to reenter all your parameters again.


For Contact info - See Website



On Tue, Jun 18, 2019 at 7:46 AM long83dt@... [canard-aviators] <canard-aviators@...> wrote:


That’s what I was looking for!  Thanks Nick!




On Tue, Jun 18, 2019 at 8:51 AM -0500, "Nick U unick3@... [canard-aviators]" <canard-aviators@...> wrote:



I was able to get the RMI engine monitor to work with the plasma ignition.   If remember correctly, I had to add a small capacitor or resistor to one of the boards in the monitor.  Since I sold my instrument a while back I can’t open it up for you to check out but the person who bought my monitor (don’t recall who it was) could certainly do that.   Ron Moyer (RMI owner) states on his website he is still providing tech support.   


You can try and contact him at:  ronmow@...

The website with the manuals:

Tach input info:     




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