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Home Switch and Stepsize

2020-09-20
2020-09-24
  • Andreas Exeler

    Andreas Exeler - 2020-09-20

    Hello Robert,
    i have some question:
    I can´t set my Stepsize to 0.067, after a new connect i get an 0.6.
    (my Stepper has 200 steps, Driver is on 1/4, have a 1:3 Gear, and ist connect to the Focuser on the 1:10 Knob and the Focuser move 0.16cm at one fullturn on the 1:10 Knop)
    Is my 0.067 right?
    The Focuser is a Baader Steeltrack.

    I have a Homeswitch in the Focuser and the Focuser is not only move on the MyFocuserPro (sometimes i focus with Hand, no MyFocuserPro is not connected at this time), and so is the "last" Position in the MyFouserPro not right.
    If i turn the Focuser to max. IN (Switch is close) and set the Focuser-Positon to 0, the first Move out have no count, retry some move, untill the Switch gets open, then i can move with count.
    Can you make a "Auto-Home, a Reference-Move"?
    So the focuser will move to Home untill the switch get close and move some steps out untill the switch open and set then the Position to 0?
    Like a CNC-Mill?

    Thanks and greets
    Andreas

     
  • Andreas Exeler

    Andreas Exeler - 2020-09-20

    Hi Robert,
    i found out a Fix for me.
    Set the Focuser manualy close to home, set the Position to max. (eg. 42000) and then press home.
    when the switch hits, the move stop and then Postion get 0.
    Problem solvd!

    have you hear some problems with a rotary encoder?
    if i move a lot in and out quick with the Rotary-Encoder, some times i get a massage at the OLED (HP=open and some more, only for a few millisec. and then postion gets to 0
    Looks like a home touch, but the focuser is in the middel Pos.

    Greets
    Andreas

     
  • brownrb

    brownrb - 2020-09-23

    I can´t set my Stepsize to 0.067, after a new connect i get an 0.6.
    (my Stepper has 200 steps, Driver is on 1/4, have a 1:3 Gear, and ist connect to the Focuser on the 1:10 Knob and the Focuser move 0.16cm at one fullturn on the 1:10 Knop)
    Is my 0.067 right?

    I think it is probably incorrect. If it is that low you need to change things.
    What is focal ratio of scope
    What is distance focuser draw tube moves in full rotation of single knob and also the fine knob

    have you hear some problems with a rotary encoder?
    if i move a lot in and out quick with the Rotary-Encoder,

    You should not do that. The motor cannot move as fast as you can. You need to wait till the motor has stopped moving before turning the knob again. Think of it like you are driving along in a car and apply the brakes and push down on the throttle pedal at the same time.

    The PDF does explain that the rotary encode is NOT a good option for use as a shuttle or going long steps. If you turn the rotary knob all the time, the commands get backed up in the command queue and it is still trying to complete the first command whilst you keep turning the knob generating even more. Eventually you will cause a crash or odd-behaviour

     
  • Andreas Exeler

    Andreas Exeler - 2020-09-23

    Hello Robert,
    i have two Baader Steeltrack, one on a 10" f10 Meade ACF (2540mm) and one on a 10" f5 Newon (1254mm).
    The Steeltrack´s move 19mm on one turn of the single knob and 1,6mm on one turn of the fine knob.

    The Beltdrive is on the fine knob (36 teeth) the Stepper (200 steps) has a 12 teeth pulley, and the driver is on 1/4 step.

    The Rotary encoder is on single-step Mode (one Beep) and is on near Focus, only 5 - 10 steps in and out, but a "quick" direction change, then get the position to 0
    Thanks for help
    Greets
    Andreas

     
  • brownrb

    brownrb - 2020-09-24

    Hi
    So much for 10 steps in the CFZ. You have way too much reduction there.
    The spreadsheet shows your configuration for each setup.
    You should consider changing to full steps and connecting to the single focus knob to get the numbers into the right range.

    Again with rotary encoder, it is not the best way to move the controller, you will run into problems because the controller ends up lagging behind the commands and something will screw up. I might look into rewriting the code in the next release

     
  • Andreas Exeler

    Andreas Exeler - 2020-09-24

    Hi Robert,
    the Steeldrive ist prepared for Motorfocus (Baader Steeldrive) on the fine knob, i will check the single knob.
    i use one Cable (8 pol) for the Stepper and the homeswitch, may there is some noise on the wire for the switch, will check this.
    Thanks for help
    Greets
    Andreas

     
  • brownrb

    brownrb - 2020-09-24

    I can´t set my Stepsize to 0.067, after a new connect i get an 0.6.
    As I stated, that is just way way too small, you should reconfigure things so you have around 10 steps within the CFZ, not hundreds or thousands. I have never seen a stepsize that low which means your gear train is way too much.

    if i move a lot in and out quick with the Rotary-Encoder,
    WAIT till the current move finishes before turning the RE again

    Did you put ferrite core on the cable for the HPSW as outlined in the PDF. You must do this to reduce noise.

    You cannot use long cables with HPSW or rotary encoder, keep cables short as possible.

    Did you also put in the capacitors required for using the RE, without these you will get bad results.

    Can you make a "Auto-Home, a Reference-Move"?
    So the focuser will move to Home untill the switch get close and move some steps out untill the switch open and set then the Position to 0?

    It already does that, this is how the hpsw works
    1. If moving towards 0 [note that 0 represents the focuser draw tube all the way IN] and position becomes 0 and the HPSW is not yet activated, then the focuser will keep moving till the HPSW closes. then back out and stop as soon as the hpsw opens and sets this to position 0
    2. If moving towards 0 and the HPSW closes and the position is greater than 0, then the focuser will back out till the HPSW opens and then sets the position to 0

    1. and 2. above is limited to 200 steps before giving up

    I suspect your hpsw is getting confused BECAUSE you have such a low step size caused by all your reduction [stepmode 1/4, then using 1:3 gear ratio, then attaching to fine focus knob 1:10] on an f11 scope - the is no way the HPSW can work on a system with a stepsize of 0.067 [think about that - 0.067 * 200 most steps to move before giving up is 13.4 microns. A human hair is about 50 microns - that means the distance for your setup is nearly only 1/4 the width of the human hair so no wonder the hpsw will not work. It all has to do with your stepsize.
    The following video will help
    https://www.youtube.com/watch?v=J6vh_iS2JsE

    So you will have to
    go to full steps
    attach to single focus knob
    with the aim of getting around 10steps in the CFZ. I have provided you with spreadsheet so you see what is required.

    Cheers
    Robert

     

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