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need help with 35A ESC — Parallax Forums

need help with 35A ESC

RobocopRobocop Posts: 9
edited 2007-03-06 00:08 in Robotics
I'm currently trying to replace my BOE bot servos with brushless motors. I have a 35a esc to power the motors and the esc is hooked up to its own battery source. I tried·plugging the esc·in pin 12, but no luck. I would appreciate any ideas or·simple lines of code as an example.

Thanks·smile.gif

Comments

  • Bruce BatesBruce Bates Posts: 3,045
    edited 2007-03-04 12:55
    Josh -

    What's probably missing is a connection between the two power supplies. You will need to connect the GROUNDS (NEGATIVE terminals) ONLY between the two power supplies.

    Regards,

    Bruce Bates

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  • RobocopRobocop Posts: 9
    edited 2007-03-05 05:21
    Could you please explain why the two power supplies have to be connected to each other if The motor and esc are powered by a lipo battery and the Boe Bot is powered by its own battery pack.

    Thanks
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2007-03-05 10:27
    Josh -

    You have TWO systems which need a common point of reference if they are to operate together. Voltage is defined as the difference of two potentials. If those seperate systems have no common point of reference, then the voltages used by each can never be the
    same or equivalent.

    If. however, you connect the grounds (ONLY) together, now thre IS a common point of reference and there can be equivalence, and the systems will be able to "communicate" with each other properly. Don't get the idea that the entire power supplies are connected together, as that is NOT the case.

    There may be better ways of explaining it, but that's how I think about it. I hope that didn't confuse you more smile.gif

    Regards,

    Bruce Bates

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  • slamerslamer Posts: 52
    edited 2007-03-05 17:51
    Questions: What is the make and model of the speed controller? Is it designed to work with pwm signals from radio receiver, like from a RC plane? The reasons I'm asking these questions is that some of those speed controllers may use seperate or isolated circuits for their inputs and outputs. So the Stamp would probably have to connect to the input side using the Signal input pin and the Stamp would also have to provide Ground to the ground pin on the Input side of the controller as well.

    When connecting a signal to the input side of a controller providing ground is just as important as providing the position signal. The ground from whatever you are trying to talk to a controler with is the reference. Without a ground reference the speed controller can not read a signal. Do you have the literature or the wiring diagram that came with the controller?

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    undefinedundefinedundefinedundefinedSteven Kirk Nelson (slamer)

    Team K.I.S.S
    Build Safe, Build Mean, Build Strong!
  • RobocopRobocop Posts: 9
    edited 2007-03-05 19:49
    The ESC is a Castle Creation 35A. I originally bought it for my rc helicopter. Also the ESC has a built in battery eliminating circuit (BEC). I beleive i have he manual for the esc somewhere, i'll have to look for it.
  • slamerslamer Posts: 52
    edited 2007-03-05 20:53
    Is it like this one?·

    CASTLE CREATIONS PHOENIX-35

    http://www.flyhighhobbies.com/product_info.php?products_id=705&osCsid=71d377540293902d69269e6149dcb754

    phx35.jpg



    With this manual?

    http://www.3dhobbyshop.com/images/Phoenix-35.pdf







    CSEPHX35.jpg




    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    undefinedundefinedundefinedundefinedSteven Kirk Nelson (slamer)

    Team K.I.S.S
    Build Safe, Build Mean, Build Strong!
  • RobocopRobocop Posts: 9
    edited 2007-03-05 21:55
    yeah thats the one
  • slamerslamer Posts: 52
    edited 2007-03-06 00:08
    Ok this could get a little tricky to use. This speed controller has a built in BEC basically a voltage regulator that's supposed to power a receiver. So you dont want to just plug it into your BOE without disconnecting the RED wire from the little servo connector that would normally connect to a radio receiver. The BOE has it's own regulator and it probably would not like it. Neither would the speed controllers (BEC)·regulator. They would probably try and kill each other.· See note 4.0 in the .pdf file

    [font=TimesNewRoman,Bold size=2]4.0 Using the Features of Your [/font][font=Arial,BoldItalic size=2]Phoenix-35.
    [/font][font=TimesNewRoman,Bold size=1]BEC     [/font]- The BEC power is supplied to the receiver and servos through the receiver connector wires. If you
    wish to disable the BEC and use a separate receiver battery (required for the use of more than twelve cells),
    you must first cut the red wire in the trio of receiver wires. Simply use a pair of wire cutters to remove a
    short section of the red wire near the receiver connector, and be sure to insulate the cut wire with a bit of
    electrical tape.

    Then you may safely use a the BOE board's·battery and power supply·with your controllers input side.
    After doing that then yes you can plug·it into the servo jack for P12 or X5 on the BOE board. Make sure you plug the speed controller plug with the brown wire oriented to the pin labled Black (ground) on X5. The orange wire on the little servo connector should be connected to the P12.
    Your next challange:
    In the Manual it mentions that this controller is programable and it has some safety features as well.

    [font=TimesNewRoman,Bold size=2]3.0 Flying with Your [font=Arial,BoldItalic size=2]Phoenix-35.[/font][font=TimesNewRoman,Bold size=2]:
    [/font][font=TimesNewRoman,Bold size=1]ALWAYS PERFORM A RANGE CHECK BEFORE FLYING WITH ANY NEW SPEED
    CONTROLLER! PERFORM YOUR RANGE CHECK AT FULL THROTTLE, HALF THROTTLE
    AND NO THROTTLE.
    [/font][font=TimesNewRoman,Italic size=1]Initialization sequence: (This is with a radio but it shows the power up sequence for the controller)
    [/font]1. Connect the speed controller receiver connector to the proper channel on your receiver (usually channel 3)
    2. Turn on your transmitter. (This will be your Basic Stamp program)
    3. Connect the main power battery to the speed controller.
    4. The speed controller will remain disarmed (will not operate) until it sees more than four seconds of "brake" throttle. Move the throttle arm to the lowest position on your transmitter, wait at least four seconds, and then test the controller to make sure that the throttle operates.
    Your going to have to write a program that sends a no throttle or braking signal to the controller from the Stamp for four seconds when you turn on the main power to the controller
    Probably a·PULSOUT command with a value of·less than 750·or so would do it. After this start up routine is finished a value greater than 750 should get your motor running.
    Your goint to have to do a bit of testing to see what values will work.
    Oh ya if you plan on making your machine run in reverse and forward·then you will have to add·some circuitry to switch two of the wires on·the output side of the controller...
    [/font]You should learn a lot from this project it's a good one..

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    undefinedundefinedundefinedundefinedSteven Kirk Nelson (slamer)

    Team K.I.S.S
    Build Safe, Build Mean, Build Strong!
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