X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rwcrmhc14.comcast.net ([204.127.192.84] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1221710 for flyrotary@lancaironline.net; Sun, 02 Jul 2006 23:15:57 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.192.84; envelope-from=wschertz@comcast.net Received: from 7n7z201 (c-24-7-194-200.hsd1.il.comcast.net[24.7.194.200]) by comcast.net (rwcrmhc14) with SMTP id <20060703031512m1400nueree>; Mon, 3 Jul 2006 03:15:13 +0000 Message-ID: <005701c69e4e$e4109ed0$c8c20718@7n7z201> From: "Bill Schertz" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EM-2 question for Tracy Date: Sun, 2 Jul 2006 22:15:09 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0054_01C69E24.FACC92C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_0054_01C69E24.FACC92C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageThanks Rusty, that describes the behavior exactly. 12V supply, = 12V prepackaged LED that glows dimly when power is applied to EM-2. Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 02, 2006 9:01 PM Subject: [FlyRotary] Re: EM-2 question for Tracy I have an LED (designed for 12V) wired up for the alarm light, and it = comes on (not flashing, steady) at what seems to be about half = brightness when power is applied to the EM-2. =20 Hi Bill, I had the exact same problem with the current EM-2 (all in one), but = not with the earlier one (separate electronics box). In both cases, I = used the exact same super bright LED's from the Shack of Rat. =20 In talking to Tracy, my understanding is that the alarm signal pin is = on a 5V pull up, with a 10k ohm resistor. When the EM-2 wants the light = on, it grounds the pin, but when it's "off", the pin would be sitting at = 5V. If you tie the light to 12V, then there's a 7V potential across the = light, with a 10k ohm resistor in series. This will allow some current = to flow, and would probably not be noticeable on an incandescent lamp, = but for LED's, it will appear to be on, but dim. =20 The fix was to use one of the EM-2 5V outputs for the LED alarm light = power. This gives no voltage differential when the light is supposed to = be off, and 5V differential when on. =20 If you are using a pre-packaged LED that's made for 12V, and you use = 5V instead, it will work but will be dimmer than it would have been with = 12V. You may have to use a different LED. =20 Tracy may also have a better answer now, so stand by for the real = answer :-) Cheers, Rusty (single rotor engine currently installed on the hanger floor) ------=_NextPart_000_0054_01C69E24.FACC92C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Thanks Rusty, that describes the = behavior exactly.=20 12V supply, 12V prepackaged LED that glows dimly when power is applied = to=20 EM-2.
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Sunday, July 02, 2006 = 9:01 PM
Subject: [FlyRotary] Re: EM-2 = question=20 for Tracy

I have an LED (designed for = 12V)=20  wired up for the alarm light, and it comes on (not flashing, = steady) at=20 what seems to be about half brightness when power is applied to the=20 EM-2.  
 
Hi Bill,
 
I had the exact same problem with the = current EM-2=20 (all in one), but not with the earlier one (separate electronics = box). =20 In both cases, I used the exact same super bright LED's from the Shack = of Rat. 
 
In talking to Tracy, my understanding is = that the=20 alarm signal pin is on a 5V pull up, with a 10k ohm resistor.  = When the=20 EM-2 wants the light on, it grounds the pin, but when it's "off", the = pin=20 would be sitting at 5V.  If you tie the light to 12V, then = there's a 7V=20 potential across the light, with a 10k ohm resistor in series.  = This will=20 allow some current to flow, and would probably not be noticeable on an = incandescent lamp, but for LED's, it will appear to be on, but=20 dim.  
 
The fix was to use one of the EM-2 5V = outputs for the=20 LED alarm light power.  This gives no voltage = differential when=20 the light is supposed to be off, and 5V differential when=20 on.  
 
If you are using a pre-packaged LED that's = made for=20 12V, and you use 5V instead, it will work but will be = dimmer=20 than it would have been with 12V.   You may have to use a = different=20 LED. 
 
Tracy may also have a better answer now, so = stand by=20 for the real answer :-)
 
Cheers,
Rusty (single rotor engine currently = installed on the=20 hanger floor)
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