Tracy,

One of the EC2's was updated 01/30/2009 and the other was updated 05/04/2009.  While there is a difference in these two EC2's as to how they determine which regions of the MAP table to use, they both are similar with regard to the low RPM coil dwell times.

Abnormally short (or long) dwell times are observed from the minimum RPM that the EC2 generates signals up to the "threshold" at around 1200 RPM.  Above that threshold, dwell times are consistently in the range of 4-5 ms.  

Steve Boese

________________________________________
From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of Tracy Crook [tracy@rotaryaviation.com]
Sent: Thursday, November 26, 2009 8:05 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Ground isn't ground

Steve, I was looking at the wrong image (the one you sent of the CAS & dwell at cranking speed of ~150 rpm.)  .  I must have missed this other one when you posted it.   I'll take a look at the 1200 rpm dwell behavior again.   I never noticed that.  Possibly because 1200 is well above cranking speed but below my idle speed of 1600 rpm.

Do you recall the date of your last EC2 update?  The low rpm dwell algorithm has changed a few times.

Tracy