---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 07/08/17: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:00 AM - Re: Re: IVO Prop current limiter (Paul A. Fisher) 2. 08:14 AM - Re: Re: IVO Prop current limiter (Alec Myers) 3. 10:45 AM - Re: Re: IVO Prop current limiter (Alec Myers) ________________________________ Message 1 _____________________________________ Time: 07:00:32 AM PST US Subject: Re: AeroElectric-List: Re: IVO Prop current limiter From: "Paul A. Fisher" The software that Bob describes would be pretty simple to write for the PIC12F683 chip, the same chip we used for the wig-wag open source project. I'll volunteer to contribute the software if someone wants to pursue Bob's hardware design using a PIC chip instead of the Arduino as an open source project. Paul Fisher On 7/7/2017 3:03 PM, Robert L. Nuckolls, III wrote: > At 11:16 AM 7/6/2017, you wrote: >> >> >> > This might be another opportunity for an open source >> > project. Once you've finely tuned the code, we can >> > poke it into chips for mounting on a dedicated >> > ecb . . . have you considered solid-state >> > switching as opposed to relay? >> >> >> Bob, >> >> I'm open to any of your great ideas. >> I had not considered a solid-state switch instead of a relay, >> but that does sound like a good way to go. >> >> It would be nice to have this in a small package. >> Right now, I have the Arduino (clone) board in an enclosure, >> and the other components in the separate enclosure I had >> been using for your original circuit. > > Yup . . . make it work on the bench then > 'distill' it . . . > > Do I recall correctly that once you have > 'golden code' in the silicon, the chip > can be lifted out and dropped into an > embedded controller with minimized > peripherals? > > If I were stuffing this functionality into an > 8-pin PIC chip, I would explore something > like this . . . > > Emacs! > > Set up Q1/R2/Q3 as a classic, ultra-fast current > limiter. Select R2 to target stall motor current > limit. Current limit is approximately > > I(limit) = Vbe(Q3)/R1 > > Vbe(Q3) is about 0.6 volts. Hence, setting > R1 at 0.1 ohms would get you a 6A current > limit. I think we were shooting for 9A so > R1 = 0.066 ohms. I would parallel a number > of resistors on an ECB to achieve 66 milliohms. > > Q1 doubles as a motor controller turned OFF > by clamping gate to ground with Q4. > > D8/D9/R10/C11/Z12 conditions the COMMAND SENSE > signal to a discrete input. > > R5/C6 conditions a CURRENT LIMIT SENSE input > to an analog input. > > Q4 is a software driven clamp to remove drive > from Q1 during a LIMIT CURRENT shut down. > > The +12 source in schematic above can be > BUS, a precision 5v source ie easily acquired for > small uC chips with a circuit like this: > > Emacs! > > > Smartware would read something like this: > > Power-up routine SETS a LIMIT LATCH which > drives gate of Q4 HI. > > A rising edge on COMMAND SENSE clears the > LIMIT LATCH which removes drive from gate of Q4. > > LIMIT SENSE is monitored for input greater > than 0.5 volts for greater than 0.5 second. > Any excursion below 0.5 volts resets the > limit timer. > > If limit times out, then the LIMIT LATCH > is SET, gate of Q4 goes HI and motor power > is removed. > > This condition is sustained until next > rising edge on COMMAND SENSE. > > It looks like the tiny Arduino products > could piggy-back onto a board that hosts > the peripheral components . . . but as > long as you're making a board, you might > explore the option of programming a chip > in an Arduino development system for > dropping into your target ECB. > > To the extend that any of this is useful, feel > free to adopt or adapt as you see fit. > > > Bob . . . > ________________________________ Message 2 _____________________________________ Time: 08:14:07 AM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: IVO Prop current limiter If you're going to use a pic you can dispense can > On Jul 8, 2017, at 9:59 AM, Paul A. T. 743 Fisher wr ote: > > The software that Bob describes would be pretty simple to write for the PI C12F683 chip, the same chip we used for the wig-wag open source project. I' ll volunteer to contribute the software if someone wants to pursue Bob's har dware design using a PIC chip instead of the Arduino as an open source proje ct. > > Paul Fisher > >> On 7/7/2017 3:03 PM, Robert L. Nuckolls, III wrote: >> At 11:16 AM 7/6/2017, you wrote: >>> >>> >>> > This might be another opportunity for an open source >>> > project. Once you've finely tuned the code, we can >>> > poke it into chips for mounting on a dedicated >>> > ecb . . . have you considered solid-state >>> > switching as opposed to relay? >>> >>> >>> Bob, >>> >>> I'm open to any of your great ideas. >>> I had not considered a solid-state switch instead of a relay, >>> but that does sound like a good way to go. >>> >>> It would be nice to have this in a small package. >>> Right now, I have the Arduino (clone) board in an enclosure, >>> and the other components in the separate enclosure I had >>> been using for your original circuit. >> >> Yup . . . make it work on the bench then >> 'distill' it . . . >> >> Do I recall correctly that once you have >> 'golden code' in the silicon, the chip >> can be lifted out and dropped into an >> embedded controller with minimized >> peripherals? >> >> If I were stuffing this functionality into an >> 8-pin PIC chip, I would explore something >> like this . . . >> >> <5a5abb6.jpg> >> >> Set up Q1/R2/Q3 as a classic, ultra-fast current >> limiter. Select R2 to target stall motor current >> limit. Current limit is approximately >> >> I(limit) = Vbe(Q3)/R1 >> >> Vbe(Q3) is about 0.6 volts. Hence, setting >> R1 at 0.1 ohms would get you a 6A current >> limit. I think we were shooting for 9A so >> R1 = 0.066 ohms. I would parallel a number >> of resistors on an ECB to achieve 66 milliohms. >> >> Q1 doubles as a motor controller turned OFF >> by clamping gate to ground with Q4. >> >> D8/D9/R10/C11/Z12 conditions the COMMAND SENSE >> signal to a discrete input. >> >> R5/C6 conditions a CURRENT LIMIT SENSE input >> to an analog input. >> >> Q4 is a software driven clamp to remove drive >> from Q1 during a LIMIT CURRENT shut down. >> >> The +12 source in schematic above can be >> BUS, a precision 5v source ie easily acquired for >> small uC chips with a circuit like this: >> >> <5a5ac43.jpg> >> >> >> Smartware would read something like this: >> >> Power-up routine SETS a LIMIT LATCH which >> drives gate of Q4 HI. >> >> A rising edge on COMMAND SENSE clears the >> LIMIT LATCH which removes drive from gate of Q4. >> >> LIMIT SENSE is monitored for input greater >> than 0.5 volts for greater than 0.5 second. >> Any excursion below 0.5 volts resets the >> limit timer. >> >> If limit times out, then the LIMIT LATCH >> is SET, gate of Q4 goes HI and motor power >> is removed. >> >> This condition is sustained until next >> rising edge on COMMAND SENSE. >> >> It looks like the tiny Arduino products >> could piggy-back onto a board that hosts >> the peripheral components . . . but as >> long as you're making a board, you might >> explore the option of programming a chip >> in an Arduino development system for >> dropping into your target ECB. >> >> To the extend that any of this is useful, feel >> free to adopt or adapt as you see fit. >> >> >> >> >> Bob . . . >> > ________________________________ Message 3 _____________________________________ Time: 10:45:55 AM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: IVO Prop current limiter Sorry - defective iPhones and all that. Possible simplifications to consider: - If you=99re using a PIC maybe you could dispense with the current limiter. If you sense the current the PIC can send the FET high impedance within a few microseconds. - dispense with the command sense input, and power the PIC with a simple potential divider from the command sense network instead. To reset the timer, remove the power shutting down the PIC and rebooting it when power is restored. > On Jul 8, 2017, at 11:12 AM, Alec Myers wrote: > > > If you're going to use a pic you can dispense can > On Jul 8, 2017, at 9:59 AM, Paul A. T. 743 Fisher > wrote: > >> The software that Bob describes would be pretty simple to write for the PIC12F683 chip, the same chip we used for the wig-wag open source project. I'll volunteer to contribute the software if someone wants to pursue Bob's hardware design using a PIC chip instead of the Arduino as an open source project. >> >> Paul Fisher >> >> On 7/7/2017 3:03 PM, Robert L. Nuckolls, III wrote: >>> At 11:16 AM 7/6/2017, you wrote: >>>> >>>> >>>> > This might be another opportunity for an open source >>>> > project. Once you've finely tuned the code, we can >>>> > poke it into chips for mounting on a dedicated >>>> > ecb . . . have you considered solid-state >>>> > switching as opposed to relay? >>>> >>>> >>>> Bob, >>>> >>>> I'm open to any of your great ideas. >>>> I had not considered a solid-state switch instead of a relay, >>>> but that does sound like a good way to go. >>>> >>>> It would be nice to have this in a small package. >>>> Right now, I have the Arduino (clone) board in an enclosure, >>>> and the other components in the separate enclosure I had >>>> been using for your original circuit. >>> >>> Yup . . . make it work on the bench then >>> 'distill' it . . . >>> >>> Do I recall correctly that once you have >>> 'golden code' in the silicon, the chip >>> can be lifted out and dropped into an >>> embedded controller with minimized >>> peripherals? >>> >>> If I were stuffing this functionality into an >>> 8-pin PIC chip, I would explore something >>> like this . . . >>> >>> <5a5abb6.jpg> >>> >>> Set up Q1/R2/Q3 as a classic, ultra-fast current >>> limiter. Select R2 to target stall motor current >>> limit. Current limit is approximately >>> >>> I(limit) = Vbe(Q3)/R1 >>> >>> Vbe(Q3) is about 0.6 volts. Hence, setting >>> R1 at 0.1 ohms would get you a 6A current >>> limit. I think we were shooting for 9A so >>> R1 = 0.066 ohms. I would parallel a number >>> of resistors on an ECB to achieve 66 milliohms. >>> >>> Q1 doubles as a motor controller turned OFF >>> by clamping gate to ground with Q4. >>> >>> D8/D9/R10/C11/Z12 conditions the COMMAND SENSE >>> signal to a discrete input. >>> >>> R5/C6 conditions a CURRENT LIMIT SENSE input >>> to an analog input. >>> >>> Q4 is a software driven clamp to remove drive >>> from Q1 during a LIMIT CURRENT shut down. >>> >>> The +12 source in schematic above can be >>> BUS, a precision 5v source ie easily acquired for >>> small uC chips with a circuit like this: >>> >>> <5a5ac43.jpg> >>> >>> >>> Smartware would read something like this: >>> >>> Power-up routine SETS a LIMIT LATCH which >>> drives gate of Q4 HI. >>> >>> A rising edge on COMMAND SENSE clears the >>> LIMIT LATCH which removes drive from gate of Q4. >>> >>> LIMIT SENSE is monitored for input greater >>> than 0.5 volts for greater than 0.5 second. >>> Any excursion below 0.5 volts resets the >>> limit timer. >>> >>> If limit times out, then the LIMIT LATCH >>> is SET, gate of Q4 goes HI and motor power >>> is removed. >>> >>> This condition is sustained until next >>> rising edge on COMMAND SENSE. >>> >>> It looks like the tiny Arduino products >>> could piggy-back onto a board that hosts >>> the peripheral components . . . but as >>> long as you're making a board, you might >>> explore the option of programming a chip >>> in an Arduino development system for >>> dropping into your target ECB. >>> >>> To the extend that any of this is useful, feel >>> free to adopt or adapt as you see fit. >>> >>> >>> >>> >>> Bob . . . >>> >> ------------------------------------------------------------------------------------- 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.