stepper motor driver help

Discussion in 'The Projects Forum' started by stylediva, Mar 24, 2012.

  1. stylediva

    Thread Starter Member

    Dec 6, 2011
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    i have a unipolar stepper motor.its specifications are TYPE:23LM-C701-01 , N/P: RH7-1048 04 , 5.2V/PHASE , 1.4 A/PHASE, 1.8 DEG/PHASE...
    i have made the l297/l298 stepper motor driver which is shown in the datasheet of l297..
    http://www.soiseek.com/STMICROELECTRONICS/L298/

    reset=1
    clock=PWM
    H/F=0
    CCW/CW=1
    vs=12v
    vref=0.5v
    Sense resistor=0.5 ohm

    but its not working..when i check that l298 gets warm and the motor is not working..can anyone help me with this??..
     
  2. DickCappels

    Moderator

    Aug 21, 2008
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    Are you clocking the input of the L1297 and getting the right outputs from that?

    What are the voltages that you measure on the various pins of the I298?
     
  3. stylediva

    Thread Starter Member

    Dec 6, 2011
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    i m getting '0' at output pins of l298..what should be the outputs at l297??...l298 gets warm before i test every output..
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Your clock signal should not be a PWM signal. It should just be a steady pulse from an astable oscillator, like a 555.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    The L298 will drop about 4v across its' high and low sides when it is passing 1.5A; that's 6W. If you're using both H-bridges, that's 4v * 1.5A * 4 = 24W; you'll burn it up mighty quickly unless you have the L298 solidly attached to a LARGE heat sink.
     
  6. stylediva

    Thread Starter Member

    Dec 6, 2011
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    will it work if i use heat sink??..what should be the input at clock of l297..??..
     
  7. shortbus

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    Sep 30, 2009
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  8. stylediva

    Thread Starter Member

    Dec 6, 2011
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    what is the difference between PWM and high low pulses??..
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    The L297 and L298 should be wired in a "chopper driver" configuration. You use a much higher supply voltage than the stepper is rated for - but of course, you have to stay about 10% below the rating of the L298.

    The datasheet for the L297 has lots of info on how to use the chopper driver feature. But, without knowing your stepper motor's current rating, resistance, or voltage rating, we won't be of much help in figuring out what voltage you need at Vref.
     
  10. stylediva

    Thread Starter Member

    Dec 6, 2011
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    sir i have attached the specifications of my motor..plz guide me what is the problem..when i check my driver without any load then it is ok..but when i attached the motor then the ground and supply becomes short and sparking is seen on the battery..and the motor does not move..plz tell me what to do..:(
     
  11. stylediva

    Thread Starter Member

    Dec 6, 2011
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    current rating is 1A for bipolar..sense resistor=0.5 ohm..so vref=I*R=0.5v
    i have set this value at 15 pin of L297..vs=12v..is is ok??..
     
  12. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    How are you wiring the motor? in your next post you say "bipolar". If wiring the motor bipolar you would ignore the "white and black" wires. Just make sure that the ends are taped but not connected to each other.
     
  13. stylediva

    Thread Starter Member

    Dec 6, 2011
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    i have ignored the black and white wiring..i have not connected them to anything..bt still the motor is not working..
     
  14. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Post your EXACT schematic.
     
  15. stylediva

    Thread Starter Member

    Dec 6, 2011
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    i have attached the schematic..
    CW/CCW=0
    HALF/FULL=0
    RESET=1
    CLOCK=pwm from AVR atmega16..
    diodes are fast recovery diodes 2A..
    pin 2,3,13,14 are connected to the coils of stepper..Black and white are left unconnected..
     
  16. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    The clock is NOT to be a PWM signal! It should only be a pulse of over two volt, What is the output voltage of the atmega16?
     
  17. stylediva

    Thread Starter Member

    Dec 6, 2011
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    i have taken pwm signal from my controller..it shows 2.5v for HIGH and 0 for LOW..i have also checked my circuit with the HIGH LOW pulses in a loop..i made one pin of my controller HIGH and after some delay i have made that LOW..but still the circuit is not working and the supply and ground becomes short..
     
  18. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Are you doing this on a 'breadboard' or a PCB?

    If on a breadboard, are all connections sound and no loose ones?

    If on a PCB check closely to see if there are any 'solder bridges' between traces. Or 'cold' joints not making good contact electrically.

    Also try switching the L297 with another one, you may have damaged this one. It happens :)
     
  19. panic mode

    Senior Member

    Oct 10, 2011
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    how is the motor wired?
    what did you do with black and white motor wires?
     
  20. stylediva

    Thread Starter Member

    Dec 6, 2011
    72
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    i am doing it on vero board..i have done this two times but both the drivers are not working..black and white wires are left unconnected..what is the mistake that i m doing..is the schematic right??..when i connect motor then the resistance between supply and ground becomes so low and it shorts..
     
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