X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 10 Jun 2005 16:23:16 -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 4.3.4) with ESMTP id 991223 for lml@lancaironline.net; Fri, 10 Jun 2005 11:53:16 -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_r1.7.) id q.1fe.3653b0b (14374) for ; Fri, 10 Jun 2005 11:52:20 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <1fe.3653b0b.2fdb1130@aol.com> X-Original-Date: Fri, 10 Jun 2005 11:52:16 EDT Subject: Re: [LML] Re: capacitance fuel gauge interface. X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1118418736" X-Mailer: 9.0 Security Edition for Windows sub 5009 -------------------------------1118418736 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 6/10/2005 9:50:11 A.M. Central Standard Time, colyncase@earthlink.net writes: Jeff wrote: -I am correct that these systems use a 3000 Hz TTL square wave? > -Is there a published (or defacto) standard? Jeff, I happened to be looking into this for other reasons. The EI display is not very picky about the freq. get details at www.buy-ei.com. Also - see attached. Colyn, Jeff: Interesting. The VM system uses the same type of probes although, if I remember correctly, the VM computer could handle freqs at least up to 20K. Higher freqs are associated with shorter sensing tubes. My header tank probe stands straight up and is 9 inches long (VM minium length was about 14 inches) -- Oops, my short probe produced freqs up to about 33K. VM said their computer couldn't handle that rate so......... I built a CMOS frequency divider (cut freq in half) out of Radio Shack parts and by consulting Mr. Mims little circuit handbooks. It is just a bulge in the connecting cable since there is 5 VDC available, along with the signal, at the probe. I see accurate fuel indications because I was very patient in getting data points in gallon increments and has been working since 1996 (wish I could have said that about everything else). Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1118418736 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 6/10/2005 9:50:11 A.M. Central Standard Time,=20 colyncase@earthlink.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Jeff=20 wrote:
-I am correct that these systems use a 3000 Hz TTL square=20 wave?
> -Is there a published (or defacto)=20 standard?

Jeff,
    I happened to be looking into this= for=20 other reasons.   The EI display
is not very picky about the=20 freq.  get details at www.buy-ei.com.
Also - see=20 attached.

Colyn, Jeff:
 
Interesting.  The VM system uses the same type of probes although,= if=20 I remember correctly, the VM computer could handle freqs at least=20= up=20 to 20K.  Higher freqs are associated with shorter sensing tubes. =20= My=20 header tank probe stands straight up and is 9 inches long (VM minium length=20= was=20 about 14 inches) -- Oops, my short probe produced freqs up to= =20 about 33K.  VM said their computer couldn't handle that rate so........= . I=20 built a CMOS frequency divider (cut freq in half) out of Radio Sha= ck=20 parts and by consulting Mr. Mims little circuit handbooks.  It is just=20= a=20 bulge in the connecting cable since there is 5 VDC available, alon= g=20 with the signal, at the probe.   I see accurate fuel indicati= ons=20 because I was very patient in getting data points in gallon increments=20= and=20 has been working since 1996 (wish I could have said that about everything el= se).=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)



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