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IVO Prop current limiter
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kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Tue May 30, 2017 10:57 am Post subject: Re: IVO Prop current limiter

Will do Bob. Thanks!

_________________
Doug

kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Wed Jun 07, 2017 12:41 pm Post subject: Re: IVO Prop current limiter

Finally got the plane out to run the engine.  I modified the circuit, adding the 100 uF capacitor and the 10 Ohm resistor per Bob's instruction.



Same behavior as before -- without engine running, the blades would change pitch fairly consistently, with an occasional premature cut-off at the extremes when trying to reverse the pitch; with the engine running, the pitch would change slightly, but the power would be cut off rapidly.



I added my multi-meter in the loop to see what kind of current was flowing.  Without the engine running, cut-off would occur, as before, at around 9 Amps.



With the engine running, the meter indicated around 2 to 8 Amps before the circuit was shut down, with most readings around 2 to 5 or so Amps before cut-off.  Not sure how reliable the meter readings are given the quick circuit shut-down.

_________________
Doug

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jun 08, 2017 5:30 pm Post subject: IVO Prop current limiter

At 03:41 PM 6/7/2017, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "kfav8r" <kfav8r(at)outlook.com>



 Finally got the plane out to run the engine.  I modified the circuit, adding the 100 uF capacitor and the 10 Ohm resistor per Bob's instruction.



 Same behavior as before -- without engine running, the blades would change pitch fairly consistently, with an occasional premature cut-off at the extremes when trying to reverse the pitch; with the engine running, the pitch would change slightly, but the power would be cut off rapidly.



 I added my multi-meter in the loop to see what kind of current was flowing.  Without the engine running, cut-off would occur, as before, at around 9 Amps.



 With the engine running, the meter indicated around 2 to 8 Amps before the circuit was shut down, with most readings around 2 to 5 or so Amps before cut-off.  Not sure how reliable the meter readings are given the quick circuit shut-down. 	


   Well . . .  fooey. This isn't going to be a 'problem'

   with your bus voltage.  Circuits of this strip are

   inherently sensitive to dv/dt (fast rise noise) effects.



   Unfortunately, I didn't push this circuit through the

   DO160 examination . . . hmmmm . . . I think I was still

   at Raytheon/Beech.  It's no doubt possible to tranquilize

   the little critter with the right test equipment but

   that's no longer in my bag of tricks.



   Let's go to plan B. In the time since that circuit

   was proposed, moving to a digital sensing, timing

   and reaction circuit makes a lot of sense. There's

   a LOT MORE separate between the bus and the parts

   that sift the fine sands of performance.



   I'm up to my eyeballs in a couple of programs now

   but I'll see if I can sketch out the diagram and

   get my super software guy to program a chip

   to try.



   Watch this space . . .



 

   Bob . . .

kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Tue Jun 27, 2017 10:37 am Post subject: Re: IVO Prop current limiter

With Bob's prompting to move on to Plan B, I put together an Arduino-based IVOProp "controller."



I bought an Arduino clone, a relay module, and a current sensing module, and wrote a program to monitor the prop current.  When the current goes above 9 Amps for a sufficiently long time, the program opens the relay and shuts off the current.  The red and green LEDS are triggered to indicate the current flowing and not flowing to the prop.  The program leaves the relay open and the red LED on for a few seconds so the pilot gets the message that a limit was reached.



I just ran the engine and put the prop through its paces, and the system seems to work well.  There might be additional tweaking to the code needed, but I think it's pretty close to good.



I'll be happy to share the code and links to the components if anyone is interested.

_________________
Doug

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jun 28, 2017 3:05 am Post subject: IVO Prop current limiter

At 01:37 PM 6/27/2017, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "kfav8r" <kfav8r(at)outlook.com>



 With Bob's prompting to move on to Plan B, I put together an Arduino-based IVOProp "controller."



 I bought an Arduino clone, a relay module, and a current sensing module, and wrote a program to monitor the prop current.  When the current goes above 9 Amps for a sufficiently long time, the program opens the relay and shuts off the current.  The red and green LEDS are triggered to indicate the current flowing and not flowing to the prop.  The program leaves the relay open and the red LED on for a few seconds so the pilot gets the message that a limit was reached.



 I just ran the engine and put the prop through its paces, and the system seems to work well.  There might be additional tweaking to the code needed, but I think it's pretty close to good. 	


   GOOD for YOU! 



  	  Quote: 	
		  I'll be happy to share the code and links to the components if anyone is interested. 	


   Yes, I'd be interested in seeing your work.



 

 

   Bob . . .

merlewagner2

Joined: 01 Jun 2016
Posts: 18
Location: Spring Hill, FL

Posted: Wed Jun 28, 2017 3:58 am Post subject: Re: IVO Prop current limiter

I would also like to take a look at your setup. I am planning on using an IVO mag prop with in flight adj. Was hoping to do just what you have already done. Way ahead of me!!!!



Merle



 	  Quote: 	
		  I'll be happy to share the code and links to the components if anyone is interested. 	




hmmm, seems I screwed up the quoting somehow..

_________________
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Commercial SEL
A & P
Building scale P51, rebuilding Tailwind W10

kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Wed Jun 28, 2017 12:00 pm Post subject: Re: IVO Prop current limiter

I'll get the info posted next week.

_________________
Doug

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jun 28, 2017 12:24 pm Post subject: IVO Prop current limiter

At 03:00 PM 6/28/2017, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "kfav8r" <kfav8r(at)outlook.com>



 I'll get the info posted next week. 	


   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 . . .

kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Thu Jul 06, 2017 8:04 am Post subject: Re: IVO Prop current limiter

Attached is the Arduino code for, and a diagram of the IVOProp controller.

For the diagram, I used part of one of Bob's drawings, and added the Arduino components.



These are the components I used:

- Funduino ATMEGA328P Development Board

- ACS712 Current Sensor Module 20A

- SLA-12VDC-SL-C 12V 30A relay module



I had never worked with Arduino before, so I just bought what I thought made sense. 

The Funduino board might be over-kill for this application; I'm sure there are plenty 

of alternatives available. The Funduino board is apparently an Arduino-compatible clone.



All of the components were purchased on eBay.



For expedience, I put the current sensor between the prop adjuster switch and ground.

It would probably be better to have the sensor between the switch and the prop, 

on one of the power lines. That would allow the code to see positive and negative readings,

depending on which direction the pitch is changing. You could then prevent further movement 

of the prop in the same direction after a limit has been reached. Right now, the code cannot 

determine in which direction the blades are moving.



The txt file is the Arduino code. Replace .txt with .ino to open it in the Arduino code editor.

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_________________
Doug

kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Thu Jul 06, 2017 8:16 am Post subject: Re: IVO Prop current limiter

 	  Quote: 	
		  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. 



Thanks,

_________________
Doug

yellowduckduo(at)gmail.co
Guest

Posted: Thu Jul 06, 2017 9:05 am Post subject: IVO Prop current limiter

For a smaller package, the 5 volt arduino clone pro mini boards are 

under $2. delivered and can replace the funduino.

In my mind that makes them a no brainer to incorporate when building 

multiple copies of something, instead of starting from scratch.

http://www.ebay.ca/itm/Pro-Mini-Enhancement-ATMEGA328P-5V-16MHz-Compatible-to-Arduino-PRO-mini-/191679508570?hash=item2ca0fd305a:g:AxIAAOSwT6pV5YIu



Boards like the funduino (uno clones) are much larger but include the 5 

volt power supply regulator and USB interface and are usually more 

convenient for one off projects or a first project.

Ken



On 06/07/2017 12:16 PM, kfav8r wrote:

 	  Quote: 	
		   

> 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.



 Thanks,



 --------

 Doug





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=470728#470728

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 07, 2017 12:04 pm Post subject: IVO Prop current limiter

At 11:16 AM 7/6/2017, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "kfav8r" <kfav8r(at)outlook.com>



 

 > 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 . . .



 [img]cid:.0[/img]



   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:



 [img]cid:.1[/img]



 

    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 . . .

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paulf(at)hughes.net
Guest

Posted: Sat Jul 08, 2017 6:00 am Post subject: IVO Prop current limiter

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:

     

      	  Quote: 	
		                At 11:16 AM 7/6/2017, you wrote:

        	  Quote: 	
		  --> AeroElectric-List         message         posted by: "kfav8r" <kfav8r(at)outlook.com> (kfav8r(at)outlook.com)

         

         

         > 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 . . .

       

       [img]cid:part1.F6F6D007.EBFDB47D(at)hughes.net[/img]

       

         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:

       

       [img]cid:part2.6F928517.BC423015(at)hughes.net[/img]

       

       

          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 . . .

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alec(at)alecmyers.com
Guest

Posted: Sat Jul 08, 2017 7:14 am Post subject: 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 <paulf(at)hughes.net (paulf(at)hughes.net)> wrote:

 	  Quote: 	
		                     

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:

     

      	  Quote: 	
		                At 11:16 AM 7/6/2017, you wrote:

        	  Quote: 	
		  --> AeroElectric-List         message         posted by: "kfav8r" <kfav8r(at)outlook.com> (kfav8r(at)outlook.com)

         

         

         > 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 . . .

alec(at)alecmyers.com
Guest

Posted: Sat Jul 08, 2017 9:45 am Post subject: IVO Prop current limiter

Sorry - defective iPhones and all that.

Possible simplifications to consider: 



- If youâ€™re 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.





 	  Quote: 	
		  On Jul 8, 2017, at 11:12 AM, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> 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 <paulf(at)hughes.net (paulf(at)hughes.net)> wrote:

 	  Quote: 	
		          

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:     

      	  Quote: 	
		                At 11:16 AM 7/6/2017, you wrote:        	  Quote: 	
		  --> AeroElectric-List         message         posted by: "kfav8r" <kfav8r(at)outlook.com> (kfav8r(at)outlook.com)                           > 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 . . .

Eric Page

Joined: 15 Feb 2017
Posts: 247

Posted: Sun Jul 09, 2017 12:05 am Post subject: IVO Prop current limiter

I've converted Bob's sketches to a CAD file.  Anyone with interest in the project please look over my work (see attached PDF) and post any changes/critiques for the group to consider.  When we're all happy, I'll turn it into a printed circuit board, stuff it with parts and a DIP-8 socket, and send it to Paul so he can add a programmed PIC to test with his code.



A couple of notes:

- I've assumed that the DPDT motor-control relay will be mounted elsewhere (off the PCB).

- I've drawn a notional wiring diagram including a switch and a second relay.  If this isn't how the IVO prop works, let me know what to change.

- I guessed at the correct PIC GPIO pins to use.  Paul, let me know if you need something different.



Things to consider:

- For BOM simplicity, I used the same 2k resistors for R1-R8, and 0.1uF for C2 and C3.  Any problems with this?

- Any other component substitutions or value changes?

- What's the desired physical envelope (PCB with mounting holes / PCB for a small potting box / something else...)?

- What type of connector(s) should be used (a DB-9 is shown)?

- Are the fuse values on the wiring diagram appropriate?

- What AWG should be specified for each wire run?

Doug (kfav8r), in order to give you credit on the schematic, would you like to send me your last name?



Cheers,

Eric

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kfav8r

Joined: 20 May 2012
Posts: 14
Location: Norman, OK

Posted: Sun Jul 09, 2017 6:01 am Post subject: Re: IVO Prop current limiter

The DPDT switch is mounted in the panel (in my case), along with the red and green LEDs.

For the Arduino setup, I have the relay and the current sensing module in a box behind the panel, and the arduino placed nearby.

On my Arduino layout drawing, the right side is from one of Bob's original drawings. He included the 10 Amp circuit breaker there, since that is what is delivered with the IVOProp.

For wiring, I used 16 AWG for any wires handling prop motor current; that is the size delivered with the prop.

My name is Doug Garland, but true credit goes to Dennis Glaeser for starting this discussion years ago, and, of course, Bob.

_________________
Doug

paulf(at)hughes.net
Guest

Posted: Sun Jul 09, 2017 6:59 am Post subject: IVO Prop current limiter

Nicely drawn Eric!Â  

          

Your message asks a lot of questions that I'm not qualified to       answer.Â  However, I can answer the question about the PIC pins you       chose - they should work fine.Â  I'll write the code based on the       brief description Bob gave in his note.Â  I'm assuming that a LIMIT       SENSE of greater than 0.5 volts for more than 0.5 seconds is the       trigger we want.Â  I'll put those values in EEPROM fields on the       chip so they are relatively easy to change if we want.     

At some point we'll need someone with an IVO prop to actually       test this and give us real world feedback.     

This is fun!     

Paul

          

     On 7/9/2017 3:05 AM, Eric Page wrote:

     

      	  Quote: 	
		                                                                I've converted                   Bob's sketches to a CAD file. Â Anyone with interest in                   the project please look over my work (see attached                   PDF) and post any changes/critiques for the group to                   consider. Â When we're all happy, I'll turn it into a                   printed circuit board, stuff it with parts and a DIP-8                   socket, and send it to Paul so he can add a programmed                   PIC to test with his code.

               

                 

               A couple of                   notes:

               - I've                   assumed that the DPDT motor-control relay will be                   mounted elsewhere (off the PCB).

               -                 I've drawn a notional wiring diagram including a switch                 and a second relay. Â If this isn't how the IVO prop                 works, let me know what to change.

               -                 I guessed at the correct PIC GPIO pins to use. Â Paul,                 let me know if you need something different.

               

                 

               Things to                   consider:

               - For BOM                   simplicity, I used the same 2k resistors for R1-R8,                   and 0.1uF for C2 and C3. Â Any problems with this?

               -                 Any other component substitutions or value changes?

               

               - What's the                   desired physical envelope (PCB with mounting holes /                   PCB for a small potting box / something else...)?

               -                 What type of connector(s) should be used (a DB-9 is                 shown)?

               -                 Are the fuse values on the wiring diagram appropriate?

               - What AWG should be specified for each wire                 run?

               

               

               Doug                 (kfav8r), in order to give you credit on the schematic,                 would you like to send me your last name?

               

               

               

               Cheers,

               

               

               Eric

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jul 09, 2017 8:07 am Post subject: IVO Prop current limiter

At 08:59 AM 7/8/2017, you wrote:



  	  Quote: 	
		  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. 	


   I'm up to my eyeballs in a couple of development

   efforts along with juggling domestic duties . . .

   but if someone wants to brassboard this project,

   I'll volunteer to package it into a readily

   duplicated product.



   I've posted a proposed schematic of the controller

   at  http://tinyurl.com/ybbtw6dp



   A minimalist approach to packaging would

   look something like this. The fat power transistor

   would be on the bottom, heat transfer surface down.

   This would facilitate using airframe for heat-sinking

   like our schottky e-bus diode did. The connector

   would be 15 pin.  The ECB footprint would be about

   1.25 x 1.75 inches.  The 'kit' would look something

   like this except that the 700-2-7 switch is

   missing.



 



 

 [img]cid:.0[/img]



 

   Oh yeah, had a gray-matter fart while crafting the

   schematic. The software can get MUCH simpler.



   On power up, the initialization CLEARS the LIMIT

   LATCH and removes gate drive from the clamping

   fet.



   The analog input is monitored for amplitude greater

   than 0.5 volts; greater than 0.5 seconds whereupon

   the LIMIT LATCH is SET, gate of clamp fet goes

   high and removed drive from the current limit fet.



   An excursion below 0.5v will reset the LIMIT

   TIMER.



   After limit time out, the condition is sustained

   until next power-down/power-up event.



   I need to keep my head down on some more pressing

   tasks for the next 10 days or so. You guys can

   shepherd this along in the mean time.  

 

   Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jul 09, 2017 8:19 am Post subject: IVO Prop current limiter

At 09:58 AM 7/9/2017, you wrote:



  	  Quote: 	
		  Nicely drawn Eric!Â  



 Your message asks a lot of questions that I'm not qualified to answer.Â  However, I can answer the question about the PIC pins you chose - they should work fine.Â  I'll write the code based on the brief description Bob gave in his note.Â  I'm assuming that a LIMIT SENSE of greater than 0.5 volts for more than 0.5 seconds is the trigger we want.Â  I'll put those values in EEPROM fields on the chip so they are relatively easy to change if we want.



 At some point we'll need someone with an IVO prop to actually test this and give us real world feedback. 	


   Yes, brass-boarding is the acid test. You guys

   had pushed this cart further down the road than

   I thought since I sat down at the keyboard last

   night.



   Both .pdf and .dwg files of my work product are

   at  http://tinyurl.com/yby3waw6  for use

   as the chefs of this design stew see fit.



   I'll be standing by . . . 



 

 

   Bob . . .

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