X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 16 Oct 2005 20:25:08 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d20.mx.aol.com ([205.188.139.136] verified) by logan.com (CommuniGate Pro SMTP 5.0c4) with ESMTP id 766253 for lml@lancaironline.net; Sun, 16 Oct 2005 07:34:01 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.139.136; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d20.mx.aol.com (mail_out_v38_r5.5.) id q.213.b943daf (4254) for ; Sun, 16 Oct 2005 07:33:13 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <213.b943daf.30839479@aol.com> X-Original-Date: Sun, 16 Oct 2005 07:33:13 EDT Subject: Re: [LML] Re: Psycho RPM Gage X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1129462393" X-Mailer: 9.0 Security Edition for Windows sub 5009 X-Spam-Flag: NO -------------------------------1129462393 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 10/15/2005 10:53:20 P.M. Central Standard Time, MikeEasley@aol.com writes: I have the JPI EDM 900 all-in-one. Everything else is working fine, so is the RPM most of the time. Last flight, after about 3.5 hours it started jumping around. Always to a higher RPM than actual, then back to normal, high enough to trigger the engine warning. Mike, Whether the pickup is a Hall effect sensor on the mag, crankshaft sensor or the old Ford tach cable converter, the output is a series of pulses, usually 1 per revolution. In the case of the LASAR mags or the Light Speed Electronic ignition, there are two pulses per rev. It would seem that the only way to get erratic higher RPM's is a loose connection that, when subjected to vibration, appears as more pulses to the computer or a circuitry problem. Let's see, 2500 rpm is about 41.7 rps or 24 milliseconds/revolution, plenty of time for havoc. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1129462393 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 10/15/2005 10:53:20 P.M. Central Standard Time,=20 MikeEasley@aol.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
I have the JPI EDM 900 all-in-one.  Everything else is working f= ine,=20 so is the RPM most of the time.  Last flight, after about 3.5 hours i= t=20 started jumping around.  Always to a higher RPM than actual, then bac= k to=20 normal, high enough to trigger the engine=20 warning.
Mike,
 
Whether the pickup is a Hall effect sensor on the mag, crankshaft=20 sensor or the old Ford tach cable converter, the output is a series of=20 pulses, usually 1 per revolution. In the case of the LASAR mags or the Light= =20 Speed Electronic ignition, there are two pulses per rev.  It would seem= =20 that the only way to get erratic higher RPM's is a loose connection that, wh= en=20 subjected to vibration, appears as more pulses to the computer or=20= a=20 circuitry problem.
 
Let's see, 2500 rpm is about 41.7 rps or 24 milliseconds/revolution, pl= enty=20 of time for havoc.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)



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