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Bidirectional serial motor speed controller. image Zoom

Bi-directional serial motor speed controller.

8 to 30 VDC bi-directional motor speed control or DC lamp dimmer. High current output section, optional fan, uses ASCII characters to operate. Made in CANADA

Fully Assembled and Tested

Availability: In stock



Product Description


    The first in our new line of motor speed controllers, its controlled using a serial port and standard ASCII characters. Use any TTY program, such as PuTTY or Hyper terminal (anyone still running 95? I bet there are a few). Use your Raspberry PI or Arduino with a bit bang serial port or a UART based serial port to control your motor. Ramp setting allows you to set a gradual increase or decrease in speed or clear it and have no ramp at all. Two storage locations allow you to switch between ramp values with a single command or clear it for no ramp, also with a single character. Fan can be set to switch ON automatically and OFF after a cooling off period. You can also set the fan to be ON all the time or OFF all of the time. The modulator uses a new algorithm which allows for smoother motor speed control. The PWM is low frequency to help cut down on motor whine. Optional power input for logic power, if you motor supply is over 15 volts DC use an external power supply for the logic, this keeps things simple and parts count to a minimum.

    Keyboard input is described below, in keeping with less data is better, one capital character will perform most operations, hex input requires two hex nibbles, will terminate and discard the hex input command.
  1. + increase PWM value
  2. - decrease PWM value
  3. % input a decimal percent value, 100 or 50.5 the actual value will be rounded depending on the current step rate used.
  4. S Stop PWM, PWM immediately set to zero outputs are cleared, no drive direction.
  5. F sets direction to Forward, if the PWM has a value its reduced to zero over time (deceleration), then direction change occurs.
  6. R sets direction to Reverse, if the PWM has a value its reduced to zero over time (deceleration), then direction change occurs.
  7. O Neutral and engaged, the PWM stays the same, the driver is disabled.

    Store preset values

    These values have no direction information.

    C moves the current PWM value into location Store 1
    D moves the current PWM value into location Store 2
    G moves Store 1 to PWM
    H moves Store 2 to PWM
    T move current deceleration value to location Store3
    U move current deceleration value to location Store4
    M move value in store3 to deceleration register
    N move value in store3 to deceleration register
    Z clears the deceleration value, same as disabling deceleration.
    J allows hex input of the deceleration value 0xFF (0 - 255)
    W allows hex input of the Option flags value 0xFF (0 - 255)
    V Toggles the Verbose option On and Off.
    L Set step rate 100 or 200 steps.
    Q Enable disable quarter stepping.
    Quarter stepping changes between two PWM values to achieve an interleaved PWM value.
    Option flags:
    Bit0 Fan always ON if set
    Bit1 Fan always OFF is set ;if both are clear its automatic.
    Bit2 Quarter step enable, quarter step allows an extra bit of resolution. Alternates between 2 PWM values.
    Bit3 Verbose enable, extra text in response if clear, minimal if set.
    Bit4 Response required if clear, no response except A'>' when finished processing.
    The PWM is always left at zero after a direction change request. Use one of the presets to move to a higher value.
    O toggles between both outputs off, and the current direction but leaves the PWM value unchanged.
    X Turns on the Fan
    Y Turns off the Fan
    The fan will turn on for any PWM value above 10% or 0x10 HEX
    The fan will turn off after aprox 2 minutes of sitting at zero percent.
    In order to set the fan mode you need to go into options, On Off or Automatic, or send Option Flags VIA Hex input.
    ? display part number and firmware revision, options, plus current status, prompt for options set.
    W will display current direction and PWM value

    P will print the current PWM value in percent.
    A displays all options and relevant data.
    ! saves all current settings, these values will be loaded on Power up.
    If a command is not recognized a A'!' will be returned.
    When '>' this character is returned the modulator has completed its task and is ready for another command.

    Setup options:

    Verbose On or Off will send extra data if available, example, ON 100.00% Forward OFF 100.00%.
    This will help cut down on data sent that's not really required.
    To save all values use '!' this will write all registers to eerom, for recall on startup.
    When a direction change is requested the modulator ramps the PWM value to zero.
    The task will take longer for higher deceleration values, wait until the ASCII '>' character has been received before issuing another.

    The high current Mosfet driver has a TVS across the supply to keep motor spikes from damaging the driver. Installing the incoming power selection jumper to N external power will route the motor positive supply to the input of the modules power.
    Optional fan is 12 volts 60mm, 4 mounting holes have been provided for stand offs.

    The modulator is based on decimal, one option is 100 steps, the next 200 steps and an interleave value called quarter stepping to allow for 400 steps in total.

  8. 8 to 30 VDC motor voltage Resistive with fan 18 amps 10 without, Inductive 10 amps with fan 5 without depending on duty cycle and ambient air temperature. This is still be determined and is listed on the side of caution.
  9. External logic supply 12 to 15 VDC 1 amp
  10. 4.3 inchs x 2.4 inchs or 110 mm x 61 mm
  11. Serial speed 19200,8,N,1
  12. DB9 serial connector on board.

    These units are built in small quantities, by hand in North America with parts from U.S and Canadian suppliers.

    This information can change at any time. If there is a command or option you require send us an email at the address listed below.

Additional Information

    Additional Information

    SKU JK066S
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