X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [216.211.128.10] (HELO mail-in03.adhost.com) by logan.com (CommuniGate Pro SMTP 5.0c6) with ESMTP id 784587 for flyrotary@lancaironline.net; Wed, 26 Oct 2005 17:53:21 -0400 Received-SPF: none receiver=logan.com; client-ip=216.211.128.10; envelope-from=JoeH@PilgrimTech.com Received: from pilgrim9 (c-67-183-14-36.hsd1.wa.comcast.net [67.183.14.36]) by mail-in03.adhost.com (Postfix) with ESMTP id 92FA82A9B44 for ; Wed, 26 Oct 2005 14:52:24 -0700 (PDT) (envelope-from JoeH@PilgrimTech.com) Reply-To: From: "Joe Hull" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: EM2 Calibration Date: Wed, 26 Oct 2005 14:52:33 -0700 Organization: Pilgrim Technologies Message-ID: <005d01c5da77$927a2910$8802a8c0@redmond.corp.microsoft.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005E_01C5DA3C.E61B5110" X-Mailer: Microsoft Office Outlook 11 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 In-Reply-To: Thread-Index: AcXaPric1v+AW5qETjq3+h8POa2QawANwj/g This is a multi-part message in MIME format. ------=_NextPart_000_005E_01C5DA3C.E61B5110 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi Joe, Something not right here. The scale factor should not be negative. The default value for oil pressure channel as shipped is +9.349. Making the EM2 user calibratable so that a variety of sensors can be used is obviously a mixed blessing and there is a limit on just how far from the default sensor you can go. Are you using the recommended sensor or something else? Try to stay with the 10 - 180 ohm (low to high) VDO pressure sensor family. Trying to calibrate with an inverse sensor (low pressure = high resistance) is theoretically possible using negative scale factor but can be devilishly tricky to do. Yep, I've got the VDO pressure sensor that came with the EM2. I measured it's resistance at zero pressure and it was 9.97 - 9.99 ohms, so it's right where it should be on the low end (I didn't measure resistance at the high end yet). I'm not sure how the calibration factors/offsets got so far off - this is really my first shot at calibrating - e.g. the low-end offset was 750-ish when I started. Anyway - any ideas on getting the scale factor positive? E.g. if I sit for 2 more hours and ratchet it up to 65,500 will it turn over? It's always shown a negative pressure from the day I turned it on - albeit an obviously wrong number even without the negative. On temp sensor calibration, do not use a low value (like ice water) as the low end calibration point. Automotive gauge sensors are not linear or accurate down there. I typically use 100 - 130 deg. F as the low end and boiling water as the upper point. Al's suggested use of an infrared temp gauge to calibrate is a good one. Yep, I read the manual and understood that point. I'm going with a thermometer in a glass of hot water - working my way via microwave to 212. I like the idea of an infrared gun - but it's hard to heat and cool the engine rapidly for repeated checks and fine tuning of the factors. Thanx for all you do for us Bozo's (at least for this Bozo!) And, did you get my email about the extra sensors you sent me that I need to pay you for? Thanxagain, Joe Hull Redmond (Seattle), Washington Cozy MkIV #991 (working on Engine & Electrical & Finishing) http://www.maddyhome.com/canardpages/pages/JoeHull/index.html ------=_NextPart_000_005E_01C5DA3C.E61B5110 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Hi = Joe,

Something not = right here. The scale factor should not be negative. The default = value for oil pressure channel as shipped is +9.349. Making the EM2 user calibratable so that a variety of sensors can be used is obviously = a mixed blessing and there is a limit on just how far from the default = sensor you can go. Are you using the recommended sensor or something = else? Try to stay with the 10 - 180 ohm (low to high) VDO pressure sensor = family. Trying to calibrate with an inverse sensor (low pressure =3D high = resistance) is theoretically possible using negative scale factor but can be devilishly = tricky to do.

Yep, I’ve got the VDO = pressure sensor that came with the EM2. = I measured it’s resistance at zero pressure and it was 9.97 – = 9.99 ohms, so it’s right where it should be on the low end (I didn’t = measure resistance at the high end yet). = I’m not sure how the calibration factors/offsets got so far off – this = is really my first shot at calibrating – e.g. the low-end offset was = 750-ish when I started.

Anyway – any ideas on getting = the scale factor positive? = E.g. if I sit for 2 more hours and ratchet it up to 65,500 will it turn over? It’s always shown a = negative pressure from the day I turned it on – albeit an obviously wrong = number even without the negative.

On temp = sensor calibration, do not use a low value (like ice water) as the low end = calibration point. Automotive gauge sensors are not linear or accurate = down there. I typically use 100 - 130 deg. F as the low end and = boiling water as the upper point. Al's suggested use of an infrared temp = gauge to calibrate is a good one.

Yep, I read the manual and = understood that point. I’m going with a thermometer in a glass of hot water = – working my way via microwave to 212. I like the idea of an infrared gun = – but it’s hard to heat and cool the engine rapidly for repeated = checks and fine tuning of the factors.

Thanx for all you do for us Bozo’s (at least for this = Bozo!)

And, did you get my email about = the extra sensors you sent me that I need to pay you for?

Thanxagain,=

Joe = Hull

Redmond (Seattle), Washington

Cozy MkIV #991 = (working on Engine & Electrical & Finishing)

http://www.maddyhome.com/canardpages/pages/JoeHull/index.html

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