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BS2 problem centering servo — Parallax Forums

BS2 problem centering servo

ArchiverArchiver Posts: 46,084
edited 2000-07-19 17:32 in General Discussion
Page 11 of Robotics! Student Workbook (ver 1.2) instructs me to
center the servos (after removing the stops on the servo gears) by
programming this in my PC:

center:
pulsout 15, 750
pause 20
go to center

I did this but the servo spins without stopping. (To stop the servo
I must delete the pulsout line and Alt-R again, or insert Sleep and
Alt-R again. When I change from Servo 1 to servo 2 (pulsout 3,750)
then servo 2 spins endlessly.

Apparently the program is not even getting to the pause statement
because I can remove "pause 20" and "go to center" and the same
result occurs.

Any clues as to what I've done wrong? I've double checked my wiring
and it matches the illustration on page 15 of Robotics! Student
Workbook. Any help is gratefully appreciated.
Don Wade

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-07-19 16:44
    Hi Don,

    Just a guess, but if you've taken out the stops and the resistor gear,
    "center" really means stop. So run your program as you have there and then
    adjust the pot on the servo until the servo is still. So think of it as
    centering the pot, not the servo shaft.

    Regards,

    Al Williams
    AWC
    * Control 8 servos at the same time:
    http://www.al-williams.com/awce/pak8.htm


    >
    Original Message
    > From: dwade@d... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=bfdidIzl674MrfISMtdoAMiRzYZmVVfhWt3Z0C5Q4C4CLTDlmrg3tM-8X6OuSGBTKvifU3pTrTU]dwade@d...[/url
    > Sent: Wednesday, July 19, 2000 10:20 AM
    > To: basicstamps@egroups.com
    > Subject: [noparse][[/noparse]basicstamps] BS2 problem centering servo
    >
    >
    > Page 11 of Robotics! Student Workbook (ver 1.2) instructs me to
    > center the servos (after removing the stops on the servo gears) by
    > programming this in my PC:
    >
    > center:
    > pulsout 15, 750
    > pause 20
    > go to center
    >
    > I did this but the servo spins without stopping. (To stop the servo
    > I must delete the pulsout line and Alt-R again, or insert Sleep and
    > Alt-R again. When I change from Servo 1 to servo 2 (pulsout 3,750)
    > then servo 2 spins endlessly.
    >
    > Apparently the program is not even getting to the pause statement
    > because I can remove "pause 20" and "go to center" and the same
    > result occurs.
    >
    > Any clues as to what I've done wrong? I've double checked my wiring
    > and it matches the illustration on page 15 of Robotics! Student
    > Workbook. Any help is gratefully appreciated.
    > Don Wade
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-07-19 16:50
    If I remember the text correctly, the answer is in there. I think it went
    something like this.

    Load that program (you are correct)
    The servo will start to spin.
    As it is doing so adjust the internal pot in the servo until the servo
    stops. This is how you know the pot is now set to 750.

    Once this calibration is done then when ever you want to stop the spinning
    servo use pulsout pin, 750, when you want it to go use any number between
    500-749 for one direction and 751-1000 for the other direction. The farther
    away from 750 the number is will make it spin faster. Sort of like a built
    in speed control.

    I haven't tried this yet, but I did read that manual, and that is what I got
    out of it. If it doesn't work, then maybe someone else here will be a
    better help.

    Shawn

    Original Message
    From: dwade@d... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=kF3My_2aCv2AirAQdkbRFNcyr3z-w_QXwXchThLLJ8WLZt-1JrVOD7yLLKAPDr3wKRFe3RfG]dwade@d...[/url
    Sent: Wednesday, July 19, 2000 8:20 AM
    To: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] BS2 problem centering servo


    Page 11 of Robotics! Student Workbook (ver 1.2) instructs me to
    center the servos (after removing the stops on the servo gears) by
    programming this in my PC:

    center:
    pulsout 15, 750
    pause 20
    go to center

    I did this but the servo spins without stopping. (To stop the servo
    I must delete the pulsout line and Alt-R again, or insert Sleep and
    Alt-R again. When I change from Servo 1 to servo 2 (pulsout 3,750)
    then servo 2 spins endlessly.

    Apparently the program is not even getting to the pause statement
    because I can remove "pause 20" and "go to center" and the same
    result occurs.

    Any clues as to what I've done wrong? I've double checked my wiring
    and it matches the illustration on page 15 of Robotics! Student
    Workbook. Any help is gratefully appreciated.
    Don Wade
  • ArchiverArchiver Posts: 46,084
    edited 2000-07-19 17:32
    I was there too.
    What I ended up doing was trial and error
    values until I found ones that worked.
    Bob




    At 03:19 PM 7/19/00 -0000, you wrote:
    >Page 11 of Robotics! Student Workbook (ver 1.2) instructs me to
    >center the servos (after removing the stops on the servo gears) by
    >programming this in my PC:
    >
    >center:
    > pulsout 15, 750
    >pause 20
    >go to center
    >
    >I did this but the servo spins without stopping. (To stop the servo
    >I must delete the pulsout line and Alt-R again, or insert Sleep and
    >Alt-R again. When I change from Servo 1 to servo 2 (pulsout 3,750)
    >then servo 2 spins endlessly.
    >
    >Apparently the program is not even getting to the pause statement
    >because I can remove "pause 20" and "go to center" and the same
    >result occurs.
    >
    >Any clues as to what I've done wrong? I've double checked my wiring
    >and it matches the illustration on page 15 of Robotics! Student
    >Workbook. Any help is gratefully appreciated.
    >Don Wade
    >
    >
    >
    >
    >
    >
    >
    >
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