---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 02/06/21: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:32 AM - Re: Re: Poor Man's Battery Tester (Robert L. Nuckolls, III) 2. 09:37 AM - Re: EFIS Erratic Temp Readings (Robert L. Nuckolls, III) 3. 12:54 PM - Re: EFIS Erratic Temp Readings () 4. 02:34 PM - Re: EFIS Erratic Temp Readings (Robert L. Nuckolls, III) 5. 04:38 PM - Re: EFIS Erratic Temp Readings (Charlie England) ________________________________ Message 1 _____________________________________ Time: 09:32:48 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Poor Man's Battery Tester At 03:41 PM 2/3/2021, you wrote: > >XH-M609 Battery Low Voltage Disconnect Module is available on eBay >for as little as $5. >Let me know if there is an error in my circuit. > >-------- >Joe Gores Looks good to me Joe. You could also use two FORWARD biased diodes to get your ~1.5 Volt supply for the clock. Let us know how this shakes out . . . Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 2 _____________________________________ Time: 09:37:25 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: EFIS Erratic Temp Readings At 11:51 PM 2/1/2021, you wrote: >If I only have sensor connected temperature >reading is different for each =9Cscan=9D and >varies by up to 150 degrees between max and min. > >If I connect more sensors readings become more >and more erratic. Even if no sensors are >connected =9Cghost=9D readings appear for >cylinders not connected with the same reading >for EGT and CHT. Ghost readings vary from between -50 to 800 degrees. > > >Hope that helps Mike, I was reviewing this thread and another thought occurs. While testing with 'no sensors' what was the condition of the open inputs? Did you put shorts across them or were they simply disconnected? Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 3 _____________________________________ Time: 12:54:39 PM PST US From: Subject: RE: AeroElectric-List: EFIS Erratic Temp Readings From: owner-aeroelectric-list-server@matronics.com On Behalf Of Robert L. Nuckolls, III Sent: February 6, 2021 9:36 AM Subject: RE: AeroElectric-List: EFIS Erratic Temp Readings At 11:51 PM 2/1/2021, you wrote: Mike, I was reviewing this thread and another thought occurs. While testing with 'no sensors' what was the condition of the open inputs? Did you put shorts across them or were they simply disconnected? No, they were not shorted, simply disconnected. Will try with them shorted next week. I would never have thought of shorting them I did remove the alternator and ran the engine with no alternator and that made no difference, Readings were still erratic Thanks Mike Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 4 _____________________________________ Time: 02:34:50 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: EFIS Erratic Temp Readings > No, they were not shorted, simply disconnected. > Will try with them shorted next week. > > I would never have thought of shorting them It used to be pretty much standard that the input to a thermocouple driven display device was pretty low impedance. Modern electronics allows us to resolve those tiny voltages with displays having very high input impedances. I have data acquisition equipment that requires unused channels to be 'tied down', i.e. shorted out. Otherwise they 'wander' in response to stimuli in the environment. Your EFIS may be similarly designed. > > > I did remove the alternator and ran the engine with > no alternator and that made no difference, > > Readings were still erratic Hmmmm . . . so probably no value in exploring noise on the DC power line. See what the thing does with all inputs 'locked down' . . . then if stable . . . try adding one t/c at a time. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 5 _____________________________________ Time: 04:38:52 PM PST US Subject: Re: AeroElectric-List: EFIS Erratic Temp Readings From: Charlie England snipped > > > Did you put shorts across them or were they > simply disconnected? > > No, they were not shorted, simply disconnected. Will > try with them shorted next week. > > I would never have thought of shorting them > > I did remove the alternator and ran the engine with no > alternator and that made no difference, > > Readings were still erratic > > Thanks > > Mike > Hi Mike, Can you remind us whether the engine is 'standard' mags & carb (or Bendix style injection), or if it has some combination of electronic ignition/fuel injection? Thanks, Charlie -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.