---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 10/29/17: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:53 AM - Re: Rotax 914 TCU interface (GTH) 2. 02:56 AM - Re: Re: Rotax/Ducati Voltage Regulator/Rectifier (GTH) 3. 05:18 AM - CB and AWG for Garmin Pitot Tube AOA (Michael Easley) 4. 09:28 AM - Re: Rotax/Ducati Voltage Regulator/Rectifier (kenryan) 5. 09:37 AM - Re: CB and AWG for Garmin Pitot Tube AOA (user9253) 6. 12:22 PM - Re: CB and AWG for Garmin Pitot Tube AOA (Robert L. Nuckolls, III) 7. 03:32 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) 8. 04:54 PM - Alt. drop out while pulling Gs... (Steve Stearns) 9. 05:19 PM - Re: Alt. drop out while pulling Gs... (Robert L. Nuckolls, III) 10. 08:11 PM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 11. 08:18 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) 12. 08:57 PM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 13. 09:01 PM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page) 14. 09:22 PM - Re: Re: Constructing an automatic RCA video camera feed splitter (Alec Myers) ________________________________ Message 1 _____________________________________ Time: 02:53:54 AM PST US Subject: Re: AeroElectric-List: Rotax 914 TCU interface From: GTH /Le 28/10/2017 13:27, Peter Pengilly a crit : / > > /Does anyone have any experience with the Rotax 914 Turbo Control Unit > interface app?/ > > /I know the TCU has the on-board adapter and a straight RS232 > interface lead will work./ > > /Where is the interface software obtained from?/ > Hi Peter, Have you tried this ? http://www.flyrotax.com/services/technical-documentation.html ? Also some info here http://www.rotax-owner.com/en/rotax-blog/item/45-64-bit-tlr Your computer must have a genuine Series port. > > // > > /The TCU in question is flashing the yellow light, meaning an > airbox/throttle position sensor is broken/disconnected./ > > /Apparently this app will indicate which sensor to look at./ > > // > > /Is the software straight forward to use?/ > The software is a bit crude, but it works, some basic info is available in the Rotax Installation Manual. We had some issues last year, and zeroed in on the wastegate binding on power on due to lead deposits. Hope this helps, -- Best regards, Gilles http://contrails.free.fr http://lapierre.skunkworks.free.fr ________________________________ Message 2 _____________________________________ Time: 02:56:57 AM PST US Subject: Re: AeroElectric-List: Re: Rotax/Ducati Voltage Regulator/Rectifier From: GTH Le 28/10/2017 20:48, user9253 a crit : > > Yeah, the small mounting contact area will not conduct much heat. But even so, every little bit helps. Use heat conductive grease. A shroud with attached blast tube will help also. > Hi all, You can also use a computer fan attached to the Voltage R/R. -- Best regards, Gilles http://contrails.free.fr http://lapierre.skunkworks.free.fr ________________________________ Message 3 _____________________________________ Time: 05:18:45 AM PST US From: "Michael Easley" Subject: AeroElectric-List: CB and AWG for Garmin Pitot Tube AOA I'm replacing my standard heated pitot tube with the Garmin heated/unregulated pitot tube/AOA. My existing wiring is 15A CB, 14 AWG, 12V system. That's based on the 100W pitot tube heater, so 8A. Garmin wants a 20A CB and 10 AWG based on the length of the run, p.61 of the G3X Install PDF. On p. 33, Garmin gives some amperages at different temperatures, 12A @ -40C, 9.25A @ 0C, 7.3A @50C, 5.85A @ 100C and 4.36A @ 175C. It's labeled "Initial Current Draw vs Probe Temperature". So my question is do I really need to run 10 AWG wire and use a 20A CB with this pitot tube? It seems like the tube might pull more than 8A briefly during warmup when it's really cold, but then it will be at or below 8A once it's warm to the touch. Due to the voltage drop at 12A it might take a few more seconds to warm up. I'm thinking my existing wiring is adequate for the new pitot tube. Thanks for the help. ________________________________ Message 4 _____________________________________ Time: 09:28:30 AM PST US Subject: AeroElectric-List: Re: Rotax/Ducati Voltage Regulator/Rectifier From: "kenryan" Thanks. I will probably sand the rough casting smooth and flat (at the mounting ears) and use the paste. I've got some temp monitoring strips so I'll determine how hot things get and then make a decision on dedicated cooling air. I will only be using under 5 amps under normal circumstances so I'm hoping the thing lasts. Sidenote: I have a German friend who is an avid aviation enthusiast and the last time he went over there he tried to get me a Silent-Hektik regulator. Unfortunately the company was non-responsive to his telephone calls. They never answered their phone nor returned his messages. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473933#473933 ________________________________ Message 5 _____________________________________ Time: 09:37:12 AM PST US Subject: AeroElectric-List: Re: CB and AWG for Garmin Pitot Tube AOA From: "user9253" I agree with you. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473934#473934 ________________________________ Message 6 _____________________________________ Time: 12:22:50 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: CB and AWG for Garmin Pitot Tube AOA >I'm replacing my standard heated pitot tube with the Garmin >heated/unregulated pitot tube/AOA. My existing wiring is 15A CB, 14 >AWG, 12V system. That's based on the 100W pitot tube heater, so >8A. Garmin wants a 20A CB and 10 AWG based on the length of the >run, p.61 of the G3X Install PDF. On p. 33, Garmin gives some >amperages at different temperatures, 12A @ -40C, 9.25A @ 0C, 7.3A >@50C, 5.85A @ 100C and 4.36A @ 175C. It's labeled "Initial Current >Draw vs Probe Temperature". > >So my question is do I really need to run 10 AWG wire and use a 20A >CB with this pitot tube? It seems like the tube might pull more >than 8A briefly during warmup when it's really cold, but then it >will be at or below 8A once it's warm to the touch. Due to the >voltage drop at 12A it might take a few more seconds to warm >up. I'm thinking my existing wiring is adequate for the new pitot tube. > >Thanks for the help. > > Pitot tube heaters have a very strong, negative > temperature coefficient. See: > >http://tinyurl.com/y78oc7z3 > > Furhter, the warm-up time constant can be pretty > slow . . . 20 seconds or more. Hence, breaker > and wiring sizes for pitot tubes might seem > overly conservative. > > Having said that, the words you quoted from > the Garmin manual seem quite clear. A cold > start from -40C (a temperature I hope you > never have to fly in), the rated peak current > is 12A, well inside the operating enevelope > for your 15A/12AWG configuration. > > I think your risks for leaving it as-is are > low. BTW, 8Amps at 12v is 100 watts . . . under > that steady state condtion, the tube will be > considerably hotter than 'warm to touch'. > > Keep in mind that pitot tubes are supposed to > shed accumulated ice at altitude (sub zero > temps)while being 'forced air cooled' by > TAS. A pitot tube on a Beechjet cruising > 41K feet will have a clear air surface temperature > of over 100C! Bob . . . ________________________________ Message 7 _____________________________________ Time: 03:32:36 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter >>I hope it isn't a big pain to alter the code for different PICs. No problem. 201 instructions, now, and still 9 bytes of data. So you saved 19 instructions by changing IC. Ive run it through PICSIM as best I can; hardware would be the next step. Unfortunately I dont have any trash PCBs for 8-pin PICs. On Oct 28, 2017, at 8:03 PM, Eric Page wrote: Alec, I think my last post on this subject (on Fri 10/20) must not have been echoed out via email, as it drew no reply at the time. To sum it up, I found another, better option for the video switch IC. That was the CD4051B, but I've since found an even better one. The CD74HC4051E has high bandwidth, is a true 8:1 mux in a single IC instead of two 4-channel switches, and it requires only 3 control lines to select one of 8 inputs. http://www.ti.com/lit/ds/symlink/cd74hc4051.pdf Since just 3 control lines are used, an 8-pin PIC is all we need, so I went back to the PIC12F683. For ease of layout, the pin assignments work best like this: 1: Vdd 2: Control B 3: Control A 4: Vpp 5: Control C 6: Switch (Left) / ICSPCLK 7: Switch (Right) / ICSPDAT 8: Vss With the CD74HC4051E and PIC12F683, I was just able to make everything fit in the space of a DB-25 backshell I found on Digi-Key (not necessarily the biggest one, but the only one I could find with a drawing that shows interior dimensions)... https://www.digikey.com/product-detail/en/norcomp-inc/983-025-010R031/925PE-ND/858537 To save a bit of space, I used a two-position male pin header instead of a tactile switch for the duplicate left switch on the board. It can be closed with one of these little shorting jumpers... https://www.digikey.com/product-detail/en/sullins-connector-solutions/SPC02SYAN/S9001-ND/76375 I hope it isn't a big pain to alter the code for different PICs. I'm sorry you didn't see my earlier post -- it's the last one in this thread... http://forum.matronics.com/viewtopic.php?t=16767494 For some reason I don't understand, the Matronics server has split this discussion into more than a dozen separate threads, some with just one or two posts. I emailed Matt Dralle about it, but he must be away or busy, as he didn't reply. Bob, I presume you must have missed my post last week also. I asked about the DB-25 backshell you posted a picture of. Do you have a part number so I can get a dimensioned drawing, or do you know the interior dimensions? It looks like it might be bigger than the one I found, and a bit more room for video signal trace routing would be welcome. Cheers, Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473918#473918 ________________________________ Message 8 _____________________________________ Time: 04:54:55 PM PST US From: Steve Stearns Subject: AeroElectric-List: Alt. drop out while pulling Gs... Greetings all, Here's an odd one... My O235 powered Longeze use a vintage externally regulated 40A Toyota alternator paired with a no-name after-market "Ford-style" regulator. (see attached pic): I've got it wired in the (Aeroelectric) traditional way with an overvoltage crowbar (visible in the picture) and a 5A breaker on the field winding. Undervoltage is redundantly apparent via a traditional Westach voltmeter and A Perihilion low-voltage indicator. All the wiring (which I have yet to re-inspect) has lots of strain-relief, all PIDG connectors etc. Nonetheless, today I observed that when I pull high positive G's, the alternator drops out (low-voltage light illuminates, voltmeter shows ~12.5 volts or so) but no excess current was observed on load meter (I didn't *specifically* check it so I might have missed the details here... But it is located adjacent to the voltmeter so I *might* have noticed something odd if present, or I might not have - remember, I was in the middle of pulling Gs...). I've been flying it, as wired for years but haven't done much pulling Gs before so I don't know if this behavior is new or not... Of course I'll be double checking connections etc. but I'm wondering if it's possible that the ford-style regulator I installed could be G sensitive? I can't image it but thought I would ask... Thanks for any insights! Steve Stearns Longeze N45FC Boulder/Longmont CO ________________________________ Message 9 _____________________________________ Time: 05:19:25 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Alt. drop out while pulling Gs... At 06:52 PM 10/29/2017, you wrote: >Greetings all, > >Here's an odd one...=C2 My O235 powered Longeze >use a vintage externally regulated 40A Toyota >alternator paired with a no-name after-market >"Ford-style" regulator. (see attached pic): > >I've got it wired in the (Aeroelectric) >traditional way with an overvoltage crowbar >(visible in the picture) and a 5A breaker on the >field winding.=C2 Undervoltage is redundantly >apparent via a traditional Westach voltmeter and >A Perihilion low-voltage indicator.=C2 All the >wiring (which I have yet to re-inspect) has lots >of strain-relief, all PIDG connectors etc. > >Nonetheless, today I observed that when I pull >high positive G's, the alternator drops out >(low-voltage light illuminates, voltmeter shows >~12.5 volts or so) but no excess current was >observed on load meter (I didn't *specifically* >check=C2 it so I might have missed the details >here... But it is located adjacent to the >voltmeter so I *might* have noticed something >odd if present, or I might not have - remember, >I was in the middle of pulling Gs...).=C2 I've >been flying it, as wired for years but haven't >done much pulling Gs before so I don't know if this behavior is new or not... > >Of course I'll be double checking connections >etc. but I'm wondering if it's possible that the >ford-style regulator I installed could be G >sensitive?=C2 I can't image it but thought I would ask... No, but alternator brushes are. They are held against a slip ring with springs that don't want to be too aggressive . . . they're relatively soft carbon on soft copper. If you could monitor output voltage from the regulator's field terminal while duplicating the event, I suspect you'll see regulator voltage go UP while alternator output is going down. I.e. the regulator may be screaming at an alternator that isn't listening. Bob . . . ________________________________ Message 10 ____________________________________ Time: 08:11:07 PM PST US Subject: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Eric Page" alec(at)alecmyers.com wrote: > 201 instructions, now, and still 9 bytes of data. So you saved 19 instructions by changing IC. > > Ive run it through PICSIM as best I can; hardware would be the next step. Unfortunately I dont have any trash PCBs for 8-pin PICs. Beauty! I've got the schematic (PDF attached) and a fist pass at the board layout complete. I exchanged a few questions/answers with a TI engineer about using the CD74HC4051E, and he told me the main "gotcha" with the part is applying a signal to an input before the IC is powered up. Apparently there's a path from the inputs to Vdd until the internal FETs are properly biased. To eliminate this possibility, I added a small circuit (bottom right corner of the schematic) consisting of a power-on reset (POR) IC and a couple of MOSFETs. The POR watches the +5V rail, and as soon as 1V is reached it begins to hold Q1 off, thus allowing Q2 to be held off by R2. Once the +5V rail reaches 4.85V and a 150mS delay elapses, the reset signal is released, Q1 turns on, turning on Q2 and allowing bus power to reach the cameras. If the +5V rail falls below 4.85V, the cameras are immediately shut off. Assuming the cameras consume ~100mA each, it should be no problem to power eight of them through a single D-Sub pin. The PCB is designed to fit between the two rows of solder cups on a DB-25 connector and be soldered in place. Q2 will probably have to have its legs bent so it lays back, over the BAT46 diode. I'd say we're about done for now. Once we see how Wade's RCA-to-USB converter and EFIS handle being switched between camera feeds, and Bob checks the camera output signal, we'll know if any changes are necessary or if we can go ahead with a hardware prototype. Eric Top side of PCB: Bottom side of PCB: Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473955#473955 Attachments: http://forums.matronics.com//files/8_ch_vid_cam_mux_rev_c_213.pdf ________________________________ Message 11 ____________________________________ Time: 08:18:16 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter I didnt get a schematic attached. But - if you have a PIC, isnt it a better idea to get the PIC to do the POR? Even if we cant contrive a way to spare a pin with an 8 pin PIC ou could go back to the 14 pin PIC at no extra cost, and have plenty of IO pins, comparators etc. No extra cost and you save the POR IC. On Oct 29, 2017, at 11:10 PM, Eric Page wrote: alec(at)alecmyers.com wrote: > 201 instructions, now, and still 9 bytes of data. So you saved 19 instructions by changing IC. > > Ive run it through PICSIM as best I can; hardware would be the next step. Unfortunately I dont have any trash PCBs for 8-pin PICs. Beauty! I've got the schematic (PDF attached) and a fist pass at the board layout complete. I exchanged a few questions/answers with a TI engineer about using the CD74HC4051E, and he told me the main "gotcha" with the part is applying a signal to an input before the IC is powered up. Apparently there's a path from the inputs to Vdd until the internal FETs are properly biased. To eliminate this possibility, I added a small circuit (bottom right corner of the schematic) consisting of a power-on reset (POR) IC and a couple of MOSFETs. The POR watches the +5V rail, and as soon as 1V is reached it begins to hold Q1 off, thus allowing Q2 to be held off by R2. Once the +5V rail reaches 4.85V and a 150mS delay elapses, the reset signal is released, Q1 turns on, turning on Q2 and allowing bus power to reach the cameras. If the +5V rail falls below 4.85V, the cameras are immediately shut off. Assuming the cameras consume ~100mA each, it should be no problem to power eight of them through a single D-Sub pin. The PCB is designed to fit between the two rows of solder cups on a DB-25 connector and be soldered in place. Q2 will probably have to have its legs bent so it lays back, over the BAT46 diode. I'd say we're about done for now. Once we see how Wade's RCA-to-USB converter and EFIS handle being switched between camera feeds, and Bob checks the camera output signal, we'll know if any changes are necessary or if we can go ahead with a hardware prototype. Eric Top side of PCB: Bottom side of PCB: Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473955#473955 Attachments: http://forums.matronics.com//files/8_ch_vid_cam_mux_rev_c_213.pdf ________________________________ Message 12 ____________________________________ Time: 08:57:21 PM PST US Subject: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Eric Page" alec(at)alecmyers.com wrote: > I didnt get a schematic attached. Apparently the server doesn't include attachments with the email echo. See: http://forums.matronics.com//files/8_ch_vid_cam_mux_rev_c_213.pdf > But - if you have a PIC, isnt it a better idea to get the PIC to do the POR? Even if we cant contrive a way to spare a pin with an 8 pin PIC ou could go back to the 14 pin PIC at no extra cost, and have plenty of IO pins, comparators etc. No extra cost and you save the POR IC. This sounds like a reasonable idea. Can the PIC12F683 monitor its own Vdd, or is a separate pin required as an input for the comparator funciton? The camera power is switched through a P-Ch MOSFET, so it's held OFF automatically by a pull-up resistor. If the PIC can pull the MOSFET gate to ground when Vdd exceeds a threshold voltage, then the POR is unnecessary, as is the N-Ch MOSFET to switch the P-Ch. Since the MOSFET's gate won't be bothered by 12V, we could use the Vpp pin to switch it during normal operation. If a separate pin is required for the comparator input, then we use a 14-pin PIC and have pins to spare. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473957#473957 ________________________________ Message 13 ____________________________________ Time: 09:01:45 PM PST US Subject: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter From: "Eric Page" Eric Page wrote: > If the PIC can pull the MOSFET gate to ground when Vdd exceeds a threshold voltage, then the POR is unnecessary, as is the N-Ch MOSFET to switch the P-Ch. Never mind this sentence; that won't work. The P-Ch gate has to be pulled up to its source voltage, which is too high for a PIC pin. So, an N-Ch is still needed to control the P-Ch. This would reverse the PIC output logic: Vdd low - output low, Vdd normal - output high. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473958#473958 ________________________________ Message 14 ____________________________________ Time: 09:22:18 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Constructing an automatic RCA video camera feed splitter The brownout reset of the PIC sounds like the right sort of idea, but it holds in reset only until the Vdd rises to between 2 and 2.2V. One could run the PIC from 2.5V derived from a 5V supply with a zener diode/resistor network to hold it off until the supply voltage reaches 4.5V, but then the maximum pin output voltage isnt guaranteed to be higher than 1.8V, which wont drive the switching inputs of the multiplexer. I dont think Im cunning enough to make that work with an 8 pin device. If you have room to go back to the 16f18323, it has an internal 1.024V fixed voltage reference and a comparator module. If we set the voltage reference as an internal input to the comparator, and connect the centre of a two resistor potential divider from Vdd to the external input of the comparator then you can easily detect when Vdd rises above an arbitrary threshold. Then you can have a logic output some chosen delay after the supply voltage rises above an arbitrary threshold. On Oct 29, 2017, at 11:56 PM, Eric Page wrote: alec(at)alecmyers.com wrote: > I didnt get a schematic attached. Apparently the server doesn't include attachments with the email echo. See: http://forums.matronics.com//files/8_ch_vid_cam_mux_rev_c_213.pdf > But - if you have a PIC, isnt it a better idea to get the PIC to do the POR? Even if we cant contrive a way to spare a pin with an 8 pin PIC ou could go back to the 14 pin PIC at no extra cost, and have plenty of IO pins, comparators etc. No extra cost and you save the POR IC. This sounds like a reasonable idea. Can the PIC12F683 monitor its own Vdd, or is a separate pin required as an input for the comparator funciton? The camera power is switched through a P-Ch MOSFET, so it's held OFF automatically by a pull-up resistor. If the PIC can pull the MOSFET gate to ground when Vdd exceeds a threshold voltage, then the POR is unnecessary, as is the N-Ch MOSFET to switch the P-Ch. Since the MOSFET's gate won't be bothered by 12V, we could use the Vpp pin to switch it during normal operation. If a separate pin is required for the comparator input, then we use a 14-pin PIC and have pins to spare. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473957#473957 ------------------------------------------------------------------------------------- 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.