Return-Path: Received: from [64.136.28.160] (HELO smtp04.lax.untd.com) by logan.com (CommuniGate Pro SMTP 4.1.1) with SMTP id 2543260 for flyrotary@lancaironline.net; Sat, 23 Aug 2003 17:33:10 -0400 Received: (qmail 26423 invoked from network); 23 Aug 2003 21:32:38 -0000 Received: from dialup-67.31.208.198.dial1.tampa1.level3.net (HELO netzero.net) (67.31.208.198) by smtp04.lax.untd.com with SMTP; 23 Aug 2003 21:32:38 -0000 Message-ID: <3F47DD23.7050403@netzero.net> Date: Sat, 23 Aug 2003 17:31:15 -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: EC2 Tach output References: Content-Type: multipart/alternative; boundary="------------070006080805080708090000" --------------070006080805080708090000 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Ok so you had it attached but unpowered. Maybe with a nice big capacitor across the supply pins? "All inputs are protected against static discharge by diode clamps to Vdd and Vss". Also, my data book has 18V as absolute max rating with 15V max recommeded. Finn Haywire wrote: > Hi Finn; > > Did you read the 768mV P-P with or without your circuit attached? > Attached. I just clipped the lead into the plug. > > What's the counter chip you're using? > CD4522BE IC BCD DIVIDE-BY-N CNTR 16-DIP > > I would imagine that you damaged it in your 20 volt tests, and it now > clamps Tracy's output to 0.7V (typical diode clamp voltage). > The one thats being used right now, was never used on the breadboard. > I've got 25 of 'em, so I used a different one for no particular reason. > > > I thought the absolute max (power supply) ratings for CMOS chips (like > 4000 and 74C.. series) were 18V. > This one is rated for 20vdc according to the spec sheet. > Certainly TTL chips (74..) are limited to 5V supply (5.25V max). > > Either that or you didn't read the scope right. > I recorded it in memory, and I can interface the scope to my computer > and send the image, for your interpretation. However it is a fairly > idiot proof instrument (that's why even I can make it work :-) as it > displays P/P, Max-P & Min-P along side of the waveform, so it's not > even really necessary to interpret the waveform > > I actually had planned to take it back to the airport and do further > testing tomorrow. I'd planned to use both channel A&B to record the > input and output of the divider chip and record it at various rpm's. > After reading your post, I'd also like to read the output without the > counter chip attached. > I finally have an inspection scheduled for noon tomorrow, so I'll > be to busy to worry about this. I'll look into it next week. Now that > Rusty seems to have found a suitable tach, and soon Tracy will be > delivering the EM2 and also is considering a tach output for a > conventional tach, this probably is not really worth the effort, > however I will still experiment a little further if only for the > educational value. > > > S. Todd Bartrim > Turbo 13B RV-9Endurance > C-FSTB > http://www3.telus.net/haywire/RV-9/C-FSTB.htm > --------------070006080805080708090000 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Ok so you had it attached but unpowered. Maybe with a nice big capacitor across the supply pins?
"All inputs are protected against static discharge by diode clamps to Vdd and Vss".
Also, my data book has 18V as absolute max rating with 15V max recommeded.

Finn

Haywire wrote:

Hi Finn;

Did you read the 768mV P-P with or without your circuit attached?

Attached. I just clipped the lead into the plug.

What's the counter chip you're using?

CD4522BE IC BCD DIVIDE-BY-N CNTR 16-DIP

I would imagine that you damaged it in your 20 volt tests, and it now clamps Tracy's output to 0.7V (typical diode clamp voltage).

The one thats being used right now, was never used on the breadboard. I've got 25 of 'em, so I used a different one for no particular reason.

I thought the absolute max (power supply) ratings for CMOS chips (like 4000 and 74C.. series) were 18V.

This one is rated for 20vdc according to the spec sheet.

Certainly TTL chips (74..) are limited to 5V supply (5.25V max).

Either that or you didn't read the scope right.

I recorded it in memory, and I can interface the scope to my computer and send the image, for your interpretation. However it is a fairly idiot proof instrument (that's why even I can make it work :-) as it displays P/P, Max-P & Min-P along side of the waveform, so it's not even really necessary to interpret the waveform

I actually had planned to take it back to the airport and do further testing tomorrow. I'd planned to use both channel A&B to record the input and output of the divider chip and record it at various rpm's. After reading your post, I'd also like to read the output without the counter chip attached.

I finally have an inspection scheduled for noon tomorrow, so I'll be to busy to worry about this. I'll look into it next week. Now that Rusty seems to have found a suitable tach, and soon Tracy will be delivering the EM2 and also is considering a tach output for a conventional tach, this probably is not really worth the effort, however I will still experiment a little further if only for the educational value.

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

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