rotary encoder as limit switch Cant find in the sketch if it is possible


Pierre Martel
 

I remember in the days of the google group someone explained how to use a rotary encoder as the limit switch for a VVC..

My setup will be using a 11.5 VVC that goes from 54 pf to 1015 pf it is driven by a 1,8 degree stepper motor connected to a 1:27 planetary gear on one side and a 1000 pulse per turn rotary encoder to track the whole thing.

I will also add 2 relay that will put one fix capacitor in parallel to the vvc and another to put in series a fix capacitor on the vvc. 

The mechanical part is ok. I need to find where to feed the 2 pulse in to the controller and make it react to it properly 

here is a photo of my mechanical setup.



Anyone can point me in the good direction?
Pierre
VE2PF
 


Immo, DL5KB
 

salut Pierre,
there is no possibility to read the/any pulses at the actual program of our loop controller...
But my experience is: you don't need an end stop switch... your stepper is not able to destroy or to do any harm to your beloved vac-c.
See my post https://groups.io/g/loopController/message/962 
and the adjacent "story"....
You will see, why not required an end stop...
All is more complicated after numerous reviews...
Have fun!
73 and a nice weekend!
Immo, DL5KB


Pierre Martel
 

OK thanks for the answer.

I am still under the impression that it was possible. 
Since the 2 input for the limit switches could be used for the 2 signals needed to catch the pulse from the rotary encoder. no modification would have been needed to do such an operation. 

Now If I could find the magic recipe to make my flex 3000 or my hermes lite 2.0 to communicate with my loop controller I would be a happy man.

Pierre VE2PF


Le sam. 25 juin 2022 à 13:59, Immo, DL5KB <dl5kb@...> a écrit :
salut Pierre,
there is no possibility to read the/any pulses at the actual program of our loop controller...
But my experience is: you don't need an end stop switch... your stepper is not able to destroy or to do any harm to your beloved vac-c.
See my post https://groups.io/g/loopController/message/962 
and the adjacent "story"....
You will see, why not required an end stop...
All is more complicated after numerous reviews...
Have fun!
73 and a nice weekend!
Immo, DL5KB


Barry - 2E0IDE
 

Hi Guys

 

I’ve used the controller since almost its inception, with a vac cap and a butterfly.

 

Physical End Stops:-

 

With the vac cap I don’t use end stops – just the min max frequency, and if you hit these, the controller just reports “Out of Range”.

 

On several occasions , when the Controller has “thrown a hissy fit”, and driven the cap to its limits, my Russian  build vac cap has not had a problem(Brick S*** House Engineering comes to mind). This is with the stepper motor current set at 80% - the stepper just stalls. NO damage to the vac cap! – Just a physical reset needed.

 

So why physical end stops?

 

OR for “belts and braces” you could just wire switched that cut the current to the stepper.

 

I’m currently going back to a butterfly (who needs end stops?) now that I can home brew and CNC cut butterfly plates.

 

MY 18.068Hz to 29.7 MHz loop – cap gives  5pf – 33 pf for 2.5M diameter loop at 22mm, and more KV than I can ever give out.

 

If anyone needs plates just email.

 

Regards

 

Barry – 2E0IDE

 

 

 

From: loopController@groups.io <loopController@groups.io> On Behalf Of Pierre Martel
Sent: 27 June 2022 15:26
To: loopController@groups.io
Subject: Re: [loopController] rotary encoder as limit switch Cant find in the sketch if it is possible

 

OK thanks for the answer.

 

I am still under the impression that it was possible. 

Since the 2 input for the limit switches could be used for the 2 signals needed to catch the pulse from the rotary encoder. no modification would have been needed to do such an operation. 

 

Now If I could find the magic recipe to make my flex 3000 or my hermes lite 2.0 to communicate with my loop controller I would be a happy man.

 

Pierre VE2PF

 

Le sam. 25 juin 2022 à 13:59, Immo, DL5KB <dl5kb@...> a écrit :

salut Pierre,
there is no possibility to read the/any pulses at the actual program of our loop controller...
But my experience is: you don't need an end stop switch... your stepper is not able to destroy or to do any harm to your beloved vac-c.
See my post https://groups.io/g/loopController/message/962 
and the adjacent "story"....
You will see, why not required an end stop...
All is more complicated after numerous reviews...
Have fun!
73 and a nice weekend!
Immo, DL5KB


Virus-free. www.avast.com


Pierre Martel
 

On  my side the Comet VVC I use will stop and won't budge at the lowest capacity. BUT at the highest capacity it will start to unscrew the capacitor shaft. at this point it will break something up. If I would use a pulley and belt the pulley is moving away from the capacitor. If I use a direct shaft the whole capacitor wants to move away from the motor/shaft assembly..

At first I was thinking of using a kind of shaft that would twist on itself if too much force is applied to it (the transparent plastic tube that I have will do this). Then I could place the motor in a cradle that would move toward or backward of the capacitor and use a limit switch to catch those movements.but the design of such cradle is not an easy task. And adding the plastic tubing does induce some backlash.  

I will try the limit less way hopefully the software limits will works.

Pierre
VE2PF

Le lun. 27 juin 2022 à 11:06, Barry - 2E0IDE <barry@...> a écrit :

Hi Guys

 

I’ve used the controller since almost its inception, with a vac cap and a butterfly.

 

Physical End Stops:-

 

With the vac cap I don’t use end stops – just the min max frequency, and if you hit these, the controller just reports “Out of Range”.

 

On several occasions , when the Controller has “thrown a hissy fit”, and driven the cap to its limits, my Russian  build vac cap has not had a problem(Brick S*** House Engineering comes to mind). This is with the stepper motor current set at 80% - the stepper just stalls. NO damage to the vac cap! – Just a physical reset needed.

 

So why physical end stops?

 

OR for “belts and braces” you could just wire switched that cut the current to the stepper.

 

I’m currently going back to a butterfly (who needs end stops?) now that I can home brew and CNC cut butterfly plates.

 

MY 18.068Hz to 29.7 MHz loop – cap gives  5pf – 33 pf for 2.5M diameter loop at 22mm, and more KV than I can ever give out.

 

If anyone needs plates just email.

 

Regards

 

Barry – 2E0IDE

 

 

 

From: loopController@groups.io <loopController@groups.io> On Behalf Of Pierre Martel
Sent: 27 June 2022 15:26
To: loopController@groups.io
Subject: Re: [loopController] rotary encoder as limit switch Cant find in the sketch if it is possible

 

OK thanks for the answer.

 

I am still under the impression that it was possible. 

Since the 2 input for the limit switches could be used for the 2 signals needed to catch the pulse from the rotary encoder. no modification would have been needed to do such an operation. 

 

Now If I could find the magic recipe to make my flex 3000 or my hermes lite 2.0 to communicate with my loop controller I would be a happy man.

 

Pierre VE2PF

 

Le sam. 25 juin 2022 à 13:59, Immo, DL5KB <dl5kb@...> a écrit :

salut Pierre,
there is no possibility to read the/any pulses at the actual program of our loop controller...
But my experience is: you don't need an end stop switch... your stepper is not able to destroy or to do any harm to your beloved vac-c.
See my post https://groups.io/g/loopController/message/962 
and the adjacent "story"....
You will see, why not required an end stop...
All is more complicated after numerous reviews...
Have fun!
73 and a nice weekend!
Immo, DL5KB


Virus-free. www.avast.com


Patrick
 

You'll likely need to do a threaded end stop.

Basically the shaft spins and moves the slide.

Something I've thought about doing too as my VVC seems to be able to unscrew as well.

A example can be found here...

https://www.pa0kv.nl/magnetic_loop.html


Pierre Martel
 

After playing a bit with the stepper motor with a small driver without the controller and watching if A it would miss some steps or not and B it would crank the capacitor too much or not I Finally came to the conclusion that if I don't tighten the plastic tubing too much to the capacitor shaft, it will turn properly AND will just slide on the shaft if too much force is applied when at max clock wise setting but it will start to unscrew the cap shaft when at the maximum un clockwise capacity. Now I just have to manage to have a limit switch at un clockwise capacity and that can be made by having the motor mount sliding just a bit when it starts to unscrew the capacitor shaft. less than 1/16th of an inch will do. A hard spring will push it back the motor toward the capacitor when turned clockwise and that the screw will turn back to its normal place. 

Now I have a 1000 step/rotation rotary encoder that will be the fine tuning knob on the controller rather than the 30ish step/rotation I have presently. 

Pierre
VE2PF

Le lun. 27 juin 2022 à 15:39, Patrick <kd7wpq@...> a écrit :
You'll likely need to do a threaded end stop.

Basically the shaft spins and moves the slide.

Something I've thought about doing too as my VVC seems to be able to
unscrew as well.

A example can be found here...

https://www.pa0kv.nl/magnetic_loop.html