1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

PWM to DC converter.

Discussion in 'Robotics & Mechatronics' started by kaarvannan, Dec 11, 2011.

  1. kaarvannan

    kaarvannan New Member

    Joined:
    Dec 11, 2011
    Messages:
    27
    Likes:
    0
    I used a 100 ohm resistor instead of a .1 ohm since there was no difference between the voltages when I used a .1 ohm resistance. I have attached an image of my O-scope displaying the two voltages. The green line- channel one was 26-27V and channel two was 19-20V , thus having a difference of 7v.
     

    Attached Files:

  2. kaarvannan

    kaarvannan New Member

    Joined:
    Dec 11, 2011
    Messages:
    27
    Likes:
    0
    ???????????
     
  3. misterT

    misterT Well-Known Member Most Helpful Member

    Joined:
    Apr 19, 2010
    Messages:
    2,697
    Likes:
    368
    Location:
    Finland
    Yeah sorry for not answering, but I really think you have only two options here:

    1) Replace the cables (shielded cable for the sensor)
    2) Use linear motor controller

    The truth is that when you have 25ft of cables close together and two of them are driven by a high-power switching amplifier, you will have serious noise problems.

    I could think this further, but you would need to provide more detailed information. What is the sensor and how it is wired (both power and signal wires). How is the motor wired (what kind of cable, what kind of filters). The physical connections and their locations are importan.. maybe even photos of the devices. I also would need to know the model of the pwm-controller and how its power supply is connected.
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. kaarvannan

    kaarvannan New Member

    Joined:
    Dec 11, 2011
    Messages:
    27
    Likes:
    0

    1) I tried the shielded cable for the sensor, it doesn't work. There is still noise.
    2) The whole point of me trying to convert PWM to DC is to use a PWM controller instead of a linear one.

    Could I give you those details you asked for via your personal email. I am really not comfortable publishing that information here.
     
  6. misterT

    misterT Well-Known Member Most Helpful Member

    Joined:
    Apr 19, 2010
    Messages:
    2,697
    Likes:
    368
    Location:
    Finland
    Did you have all the wires going to the sensor shielded? Did you ground the shield at both ends and separate from the motor?

    No.. I don't have much time to dig into this anymore. And I believe the shielded cable is the best answer.. other solutions are just guessing. You just need to do the shielding properly.
     
  7. kaarvannan

    kaarvannan New Member

    Joined:
    Dec 11, 2011
    Messages:
    27
    Likes:
    0
    ok .Thank you for all your help.
     

Share This Page