Shop OBEX P1 Docs P2 Docs Learn Events
Help With Servo Controller — Parallax Forums

Help With Servo Controller

waltwalt Posts: 27
edited 2005-03-14 02:45 in BASIC Stamp
I AM HAVING trouble with servo controler PARALLAX #28023 - rev b. My servos will not travel the full rotation.
(180) deg.· I have· tryed to change· pw = 1250 and pw = 250.


do
·pw =1250
· serout sdat, baud+$8000, [noparse][[/noparse] "!sc", ch, ra, pw.lowbyte, highbyte, cr]
pause 1000
pw = 250
serout sdat, baud+$8000, [noparse][[/noparse] "!sc", ch, ra, pw,lowbyte, pw.highbyte,cr]
pause 1000
loop

This·is the code I have been using.· ·I am· using· a JR servo NES 517

Post Edited By Moderator (Jon Williams) : 3/12/2005 5:59:27 PM GMT

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-03-12 18:44
    Walt,
    ·· Please run the following code and let me the know the firmware version you have.
    Sdat      PIN         15                              ' Serial Data I/O Pin
Baud      CON         396                             ' 2400bps on BS2
buff      VAR         Byte(3)                         ' Temp Array
 
FindPSC:
  DEBUG "Finding PSC", CR
  SEROUT Sdat, Baud+$8000, [noparse][[/noparse]"!SCVER?", CR]             ' Command to get Firmware ID
  SERIN Sdat, Baud, 500, FindPSC, [noparse][[/noparse]STR buff\3]
  DEBUG "PSC Ver: ", buff(0), buff(1), buff(2), CR
  END

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage

    Parallax Tech Support
    csavage@parallax.com
  • waltwalt Posts: 27
    edited 2005-03-13 14:33
    I tried to run this code all I get on the debug terminal is a repeating ( finding PSC ). should I use a Futabu servo


    thanks walt
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-03-13 15:48
    Your symptoms tell me that the BASIC Stamp is constantly resetting. You probably need a beefier supply to handle the load imposed by your servo(s).

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • dandreaedandreae Posts: 1,375
    edited 2005-03-13 15:59
    Also you should be receiving a version number instead of "Finding PSC".· This could indicate that the PSC maybe damaged.· I suggest contacting Parallax's tech support for further testing.

    Dave



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dave Andreae

    Tech Support
    dandreae@parallax.com
    www.parallax.com

    ·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-03-14 00:18
    Actually there could be one other issue that I can think of.· There were some changes to the firmware some time ago that actually could explain your problem.· Earlier versions of the firmware used the command:

    !SCID?

    Instead of:

    !SCVER?

    And the same sympton persists when this happens, which is is constantly says, "Finding PSC..."

    Try replacing the !SCVER? between the quotes with !SCID? and see what happens.· I'll bet it's a pre 1.2 version of the firmware.· If that's the case, I believe that may also explain your servos not travelling 180 degrees, as I think the first version of the firmware only did 90 degrees, but I will verify that tomorrow.




    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage

    Parallax Tech Support
    csavage@parallax.com
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-03-14 02:45
    walt said...
    I tried to run this code all I get on the debug terminal is a repeating ( finding PSC ). should I use a Futabu servo
    thanks walt
    Since the servo isn't active during this code that leads me to believe my earlier assumption about the firmware revision is the problem.· As for the JR servos, they work fine with the BASIC Stamp.· I have several NES-537 servos, some of which I modified for continuous rotation, and they all work fine.


    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage

    Parallax Tech Support
    csavage@parallax.com
Sign In or Register to comment.