Return-Path: Received: from [64.136.28.160] (HELO smtp01.lax.untd.com) by logan.com (CommuniGate Pro SMTP 4.1.1) with SMTP id 2534701 for flyrotary@lancaironline.net; Wed, 20 Aug 2003 08:41:35 -0400 Received: (qmail 6794 invoked from network); 20 Aug 2003 12:41:32 -0000 Received: from dialup-67.31.204.242.dial1.tampa1.level3.net (HELO netzero.net) (67.31.204.242) by smtp01.lax.untd.com with SMTP; 20 Aug 2003 12:41:32 -0000 Message-ID: <3F436C64.8090406@netzero.net> Date: Wed, 20 Aug 2003 08:41:08 -0400 From: Finn Lassen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 (nscd2) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: some progress, and more understanding References: Content-Type: multipart/alternative; boundary="------------030305000905030506030901" --------------030305000905030506030901 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit A capacitor accross the supply pins should be fine there. I was thinking about the input. Of course if your input comes from Tracy's controller, that's probably not an issue. But from anywhere else, like coil pick up, some input filtering/clamping would be wise. Finn Haywire wrote: > Hi Finn; > It is a CMOS device capable of handling 20vdc on its VDD pin. So I > didn't feel it was necessary. In reality I found it was unstable when > VDD was less than 5vdc or greater than 11vdc, so since I had a bag of > 470ohm resistors handy, I just put a voltage divider on the VDD. With > a regulated 13.8vdc it gives me just under 7 volts and a stable reading. > a side note; I originally had an internally regulated alternator > but the regulator failed (have since converted to an external reg as > per "electric Bob"). When running with the alternator tripped and less > than 12vdc, I found the tach would become erratic at high RPM's, due > to a low VDD. When alt is charging, everything is fine. > > > S. Todd Bartrim > Turbo 13B RV-9Endurance > C-FSTB > http://www3.telus.net/haywire/RV-9/C-FSTB.htm > > "Whatever you vividly imagine, Ardently desire, Sincerely believe > in, Enthusiastically act upon, Must inevitably come to pass". > > -----Original Message----- > From: Rotary motors in aircraft > [mailto:flyrotary@lancaironline.net]On Behalf Of Finn Lassen > Sent: Tuesday, August 19, 2003 8:23 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: some progress, and more understanding > > I don't see a Zener diode to clamp any spikes. > > Finn > > Haywire wrote: > >> Attached are a couple of pics of my tach divider. It can be set >> to divide by any number necessary. I can't guarantee it would >> work with any tach but it works very well with my cheap >> off-the-shelf-at-any-autoparts-store, Hastings tach. I have a few >> more if anybody wants one. >> >> >> S. Todd Bartrim >> Turbo 13B RV-9Endurance >> C-FSTB >> http://www3.telus.net/haywire/RV-9/C-FSTB.htm >> >> "Whatever you vividly imagine, Ardently desire, Sincerely >> believe in, Enthusiastically act upon, Must inevitably come to >> pass". >> >> >> The EC-2 tach output has 12 pulses per revolution, and won't >> directly work with any normal tach. Todd has made a divider >> to bring the pulse rate down to normal, and it sounds like >> it's working well. The TT that you have expects 1 pulse per >> rev, so if you don't mind dividing the rpm reading by 12... :-) >> >> >> > --------------030305000905030506030901 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit A capacitor accross the supply pins should be fine there. I was thinking about the input. Of course if your input comes from Tracy's controller, that's probably not an issue. But from anywhere else, like coil pick up, some input filtering/clamping would be wise.

Finn

Haywire wrote:
Hi Finn;
    It is a CMOS device capable of handling 20vdc on its VDD pin. So I didn't feel it was necessary. In reality I found it was unstable when VDD was less than 5vdc or greater than 11vdc, so since I had a bag of 470ohm resistors handy, I just put a voltage divider on the VDD. With a regulated 13.8vdc it gives me just under 7 volts and a stable reading.
    a side note; I originally had an internally regulated alternator but the regulator failed (have since converted to an external reg as per "electric Bob"). When running with the alternator tripped and less than 12vdc, I found the tach would become erratic at high RPM's, due to a low VDD. When alt is charging, everything is fine.
 

S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

   "Whatever you vividly imagine, Ardently desire, Sincerely believe in, Enthusiastically act upon, Must inevitably come to pass".

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Finn Lassen
Sent: Tuesday, August 19, 2003 8:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: some progress, and more understanding

I don't see a Zener diode to clamp any spikes.

Finn

Haywire wrote:
Attached are a couple of pics of my tach divider. It can be set to divide by any number necessary. I can't guarantee it would work with any tach but it works very well with my cheap off-the-shelf-at-any-autoparts-store, Hastings tach. I have a few more if anybody wants one.
 

S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

   "Whatever you vividly imagine, Ardently desire, Sincerely believe in, Enthusiastically act upon, Must inevitably come to pass".

 
The EC-2 tach output has 12 pulses per revolution, and won't directly work with any normal tach.  Todd has made a divider to bring the pulse rate down to normal, and it sounds like it's working well.  The TT that you have expects 1 pulse per rev, so if you don't mind dividing the rpm reading by 12...  :-)

 


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