X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 23 Apr 2014 11:46:56 -0400 Message-ID: X-Original-Return-Path: Received: from moutng.kundenserver.de ([212.227.126.130] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6842870 for lml@lancaironline.net; Tue, 22 Apr 2014 16:05:42 -0400 Received-SPF: none receiver=logan.com; client-ip=212.227.126.130; envelope-from=nick@beaglepup.info Received: from Asus8 (host86-168-252-43.range86-168.btcentralplus.com [86.168.252.43]) by mrelayeu.kundenserver.de (node=mreue005) with ESMTP (Nemesis) id 0MXTda-1WNpKv42VC-00WVFr; Tue, 22 Apr 2014 22:05:08 +0200 X-Original-Message-ID: <549B9F82912943E4A24170B3E45915B9@Asus8> Reply-To: "Nick Long" From: "Nick Long" X-Original-To: "Lancair Mailing List" References: In-Reply-To: Subject: Re: [LML] Re: VMS1000 pressure gauges on LNC2 X-Original-Date: Tue, 22 Apr 2014 21:04:56 +0100 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0063_01CF5E6E.83AB7860" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 16.4.3528.331 X-MimeOLE: Produced By Microsoft MimeOLE V16.4.3528.331 X-Antivirus: avast! (VPS 140422-1, 22/04/2014), Outbound message X-Antivirus-Status: Clean X-Provags-ID: V02:K0:iFXWpSe8oziFSvFBqfP10T63QHjfPulC6jIrQ8pyKQU AKExPxpyGOCpPCCc/yG/epU6+I4MrRQBnNCVT2vMbxzOiJxaAM Cy+juu2iKbTAblkwdqtaO+35sfqoNjroqKlvxAtDcjKYDQCGT9 9iO7uhpWHJO3KiJ+sCo9Rj9v8yYdNxJhpLvx+Om8sz7eH+URmi 5LNxccdgf2vDhRgQ+16vzVLdVQcWGume2YLMnH3uWdvuv64xtJ vB5EtDw/n5wuxYiLRDghO41LTnkt6dnUHdSEDXz8s+B7cqLrBc 5vDZH+lTZ5WhdsMXoEmRCc2QlbsXs7UUrPR5sLXNexbhdqhjIJ 82GiAjtgYQ07RtIvwVtw= This is a multi-part message in MIME format. ------=_NextPart_000_0063_01CF5E6E.83AB7860 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Bill, Thanks for the info. I think you have done everyone a service and = it=E2=80=99s good to know you have some drop in replacements available = at half the price I have seen them elsewhere. If you don=E2=80=99t mind, though, I=E2=80=99m going to pursue my ideas = a bit further. I quite like the idea of using off the shelf sensors and = using the same one for OP and FP. There is also the background thinking = that the VM1000 is a bit old now and that rather than building a = solution around that, I could devise something with general = applicability. Over the holiday weekend I did some more investigation. I built a rig in = my workshop to pressurise the old sensors from my air line system* and = measure the resistance changes and the voltage outputs. The two sensors = gave the right voltage changes (50 mV and 100 mV for 100 psi) but with = horrendous offsets. The zero psi values were way out. So they were = working, but not actually any use. Then I checked the VM1000 panel by injecting voltages on the FP and OP = inputs. That did exactly what was expected, but now I also know what = common mode voltages it will cope with. Anyway, I have ordered some modern sensors with 0 to 5 V outputs and = I=E2=80=99m going to scale the outputs down to suit the VM1000. I will = let you all know how I get on. If I=E2=80=99m right, then I will have = something that should work with any other monitoring systems that are = out there. Yours, Nick *not as easy as it sounds because the sensors are NPT threads and my = system is completely and utterly the way it should be =E2=80=93 British = Standard Pipe thread. From: William Rumburg=20 Sent: Monday, April 21, 2014 4:43 PM To: lml@lancaironline.net=20 Subject: [LML] Re: VMS1000 pressure gauges on LNC2 Nick - The VMS1000 oil and fuel pressures were designed for the Honeywell = MediaMate, which produces 50mV DC full-scale output when excited with = 5VDC. The MediaMate, however, is inferior, antiquated technology and = outrageously overpriced.=20 A modern, high-quality replacement is the Measurement Specialties US321. = It also produces 50mV DC when excited with 5VDC; hence, it's an = electrically-DIRECT replacement for the MediaMate = http://www.meas-spec.com/downloads/US300.pdf=20 A problem, however, is that the VMS1000's combination of 5VDC excitation = and 50mV DC full-scale output is, apparently, rarely used in industry; = hence, I couldn't locate any US321's -in the needed pressure range- for = sale despite an exhaustive search. I contacted Measurement Specialties = last August and learned that they would manufacture them at a cost of = $140 each, with a minimum order of five. So I ordered five @50 psi (fuel = pressure for fuel-injected engines) and five @100 psi (oil pressure). I = ordered them with four foot pigtails to allow direct routing to the DPU, = with no intermediate connector. Attached is a photo of them installed on = my engine. If anyone is interested, I'm offering the extra's for my = price of $140 each. Bill Rumburg N403WR (Sonic bOOm) Hello Everyone, A few weeks ago we had a discussion about this, and I then went away = and checked my installation. After measuring the voltages I concluded = that the display unit is ok, but both the Oil Pressure and Fuel Pressure = sensors are not behaving. So then I looked into replacements. There was an interesting post last = September from Bill Rumburg about using sensors from Measurement = Specialities; the originals are Honeywell Mediamates. Bill was saying the OP and FP transducers are different in their = voltage vs pressure response by a factor of 2 and he was exploring some = alternative devices. But here is another idea. Why not just find a = sensor that gives the correct output for FP? The same sensor will give = 2x the reading if used for OP, but that can be scaled down by 2 with a = simple precision resistor network. If that is correct, and I=E2=80=99ve followed the previous discussion = correctly, then Digi Key have the very item we need: = http://www.digikey.com/product-detail/en/M3421-000006-100PG/MSP6892-ND/72= 6352 What do you think, people? Yours, Nick -------------------------------------------------------------------------= ------- -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html ------=_NextPart_000_0063_01CF5E6E.83AB7860 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Hi Bill,
 
Thanks for the info. I think you have done everyone a service and = it=E2=80=99s good=20 to know you have some drop in replacements available at half the price I = have=20 seen them elsewhere.
 
If you don=E2=80=99t mind, though, I=E2=80=99m going to pursue my = ideas a bit further. I=20 quite like the idea of using off the shelf sensors and using the same = one for OP=20 and FP. There is also the background thinking that the VM1000 is a bit = old now=20 and that rather than building a solution around that, I could devise = something=20 with general applicability.
 
Over the holiday weekend I did some more investigation. I built a = rig in my=20 workshop to pressurise the old sensors from my air line system* and = measure the=20 resistance changes and the voltage outputs. The two sensors gave the = right=20 voltage changes (50 mV and 100 mV for 100 psi) but with horrendous = offsets. The=20 zero psi values were way out. So they were working, but not actually any = use.
 
Then I checked the VM1000 panel by injecting voltages on the FP and = OP=20 inputs. That did exactly what was expected, but now I also know what = common mode=20 voltages it will cope with.
 
Anyway, I have ordered some modern sensors with 0 to 5 V outputs = and I=E2=80=99m=20 going to scale the outputs down to suit the VM1000. I will let you all = know how=20 I get on. If I=E2=80=99m right, then I will have something that should = work with any=20 other monitoring systems that are out there.
 
Yours,
 
Nick
 
*not as easy as it sounds because the sensors are NPT threads and = my system=20 is completely and utterly the way it should be =E2=80=93 British = Standard Pipe=20 thread.
 
 
Sent: Monday, April 21, 2014 4:43 PM
Subject: [LML] Re: VMS1000 pressure gauges on = LNC2
 
Nick -
 
The VMS1000 oil and fuel pressures were = designed=20 for the Honeywell MediaMate, which produces 50mV DC full-scale output = when=20 excited with 5VDC. The MediaMate, however, is inferior, antiquated = technology=20 and outrageously overpriced.
A modern, high-quality replacement is = the=20 Measurement Specialties US321. It also produces=20 50mV DC when excited with 5VDC; hence, it's an electrically-DIRECT = replacement=20 for the MediaMate http://www.meas-spe= c.com/downloads/US300.pdf 
A problem, however, is that the = VMS1000's=20 combination of 5VDC excitation and 50mV DC full-scale output is, = apparently,=20 rarely used in industry; hence, I couldn't locate any US321's -in the = needed=20 pressure range- for sale despite an exhaustive search. I contacted = Measurement=20 Specialties last August and learned that they would manufacture them at = a cost=20 of $140 each, with a minimum order of five. So I ordered five @50 psi = (fuel=20 pressure for fuel-injected engines) and five @100 psi (oil pressure). I = ordered=20 them with four foot pigtails to allow direct routing to the DPU, with no = intermediate connector. Attached is a photo of them installed on my = engine. If=20 anyone is interested, I'm offering the extra's for my price of $140=20 each.
 
Bill Rumburg
N403WR  (Sonic bOOm)
Hello Everyone,
 
A few weeks ago we had a discussion about this, and I then went = away and=20 checked my installation. After measuring the voltages I concluded that = the=20 display unit is ok, but both the Oil Pressure and Fuel Pressure = sensors are=20 not behaving.
 
So then I looked into replacements. There was an interesting post = last=20 September from Bill Rumburg about using sensors from Measurement = Specialities;=20 the originals are Honeywell Mediamates.
 
Bill was saying the OP and FP transducers are different in their = voltage=20 vs pressure response by a factor of 2 and he was exploring some = alternative=20 devices. But here is another idea. Why not just find a sensor that = gives the=20 correct output for FP? The same sensor will give 2x the reading if = used for=20 OP, but that can be scaled down by 2 with a simple precision resistor=20 network.
 
If that is correct, and I=E2=80=99ve followed the previous = discussion correctly,=20 then Digi Key have the very item we need:
http://www.digikey.com/product-detail/en/M3421-000006-100PG= /MSP6892-ND/726352
 
What do you think, people?
 
Yours,
 
Nick
 

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