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Multi Drop UART — Parallax Forums

Multi Drop UART

MacTuxLinMacTuxLin Posts: 821
edited 2010-06-02 02:41 in Robotics
Hi All,

I have a newbie question. Has anyone (or thread link) done sending commands to multi-drop uart servos instead of the normal PWM type? I've written small test codes on SPIN but no respond from the servo confused.gif

Thanks.

Comments

  • allanlane5allanlane5 Posts: 3,815
    edited 2010-06-01 14:03
    Never heard of the beast. Do you have a link?· A part number perhaps?· A vendor?

    Post Edited (allanlane5) : 6/1/2010 2:09:29 PM GMT
  • MacTuxLinMacTuxLin Posts: 821
    edited 2010-06-01 14:28
    tongue.gif obviously a newbie...

    Company: RoboBuilder
    Brand: wCK series, I'm using wCK-1108T & K
    Link: http://www.robobuilder.net/eng/

    Spec:
    - Communication Multi drop Full Duplex UART serial communication
    - Baud Rate 4,800bps ~ 921,600bps(8 levels)
    - Extension Max 254 modules per channel(ID 0~253)
    - Operating Voltage 6VDC ~ 10VDC(7.4VDC~8.4VDC recommended)
    - Speed Max No Load Speed 0.15 sec/60°(wCK-1108 under recommended voltage)
    - Stall Torque Max 13kg·cm(wCK-1413 under recommended voltage)
    - Max Power 1.1W(wCK-1108, 1111), 1.4W(wCK-1413)
    - Gear Ratio 1/173(wCK-1108), 1/241(wCK-1111, 1413)
    - Control Mode Position Control, Speed Control, Torque Control
    - Control Angle 0~254(Standard Resolution), 0~1,022(High Resolution)
    - Operating Angle 0°~269°(Standard Resolution), 0°~333°(High Resolution)
    - Resolution 8 bit/1.055°(Standard Rosolution), 10 bit/0.325°(High Resolution)
    - Error Range ±0.8°(Standard Resolution)
    - Speed Level 30 levels(Position Control Mode), 16 levels(Wheel Mode)
    - Case Material Engineering Plastic
    - Gear Material POM(wCK-1108), POM+Metal(wCK-1111,1413)
    - Size 51.6 mmx27.1 mmx36.4 mm
    - Weight 45g(wCK-1108), 49g(wCK-1111,1413)
    512 x 300 - 15K
  • Mike GreenMike Green Posts: 23,101
    edited 2010-06-01 14:30
    There was a thread I think with some code attached. These servos use a default Baud around 1MHz and FullDuplexSerial can't quite go that fast. The writer used a different or modified serial driver to get it to work. I don't have a link. You'll have to browse through the old Propeller forum threads.
  • allanlane5allanlane5 Posts: 3,815
    edited 2010-06-01 14:58
    Very cool looking device. I had a difficult time finding a manual for it -- meaning after looking I couldn't find a manual for it. Still, a servo with local intelligence in a nice modular package like that with a multi-drop serial cable solves a LOT of issues in robotic building.
  • MacTuxLinMacTuxLin Posts: 821
    edited 2010-06-01 15:19
    Thanks Mike. I managed to listen in on the TX line from the controller & managed to get about 97% correct instruction set on the 8-bit command (4-bytes) by comparing the initial instructions set in the mfgr's PC software & the decoded captured data. So I thought using the same baud rate should get the servo's attention but I was wrong. Measured the original servo & signal voltage & set the same at the prop but still no good confused.gif Anyway, I search for that thread you mentioned.

    Allan, you could download the manual under the support section, page 3.
  • TimmooreTimmoore Posts: 1,031
    edited 2010-06-01 17:31
    Are you talking about this http://obex.parallax.com/objects/602/
  • MacTuxLinMacTuxLin Posts: 821
    edited 2010-06-02 02:41
    Timmoore, thank you! I'll check it out.
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