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need 100hz variable pwm signal generator — Parallax Forums

need 100hz variable pwm signal generator

sport270sport270 Posts: 82
edited 2013-09-30 17:03 in Propeller 2
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[h=2]icon1.png 100hz fixed frequency variable pwm[/h]
i have been bouncing around different solutions to a problem. I have been trying to make a variable frequency & variable duty cycle driver for 12vdc proportional solenoid. I have come to the conclusion that i only need adjustable duty cycle with a fixed 100hz frequency. The variable duty cycle is really only to set a % of flow for a proportional electrohydraulic pump control. Once i get it to the output i need, it will stay fixed, except ramping up & down to start & stop it. i have need for three of these signals to control one piece of off road equipment. And i need them to be very stable.
i was going to use some simple 555 based, but i also need serial lcd screen to show RPM of the shaft speed these pumps control. I have Quickstart propeller, Bs2, PWMPAL, DV103H, all at my disposal. Can anyone help with a absolute for sure way to do this, as i have been trying all of these and getting no where. Have to have this completed by end of weekend... :smile: Thanks for any help



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Comments

  • jmgjmg Posts: 15,144
    edited 2013-09-29 22:50
    Not quite a Prop 2 question ?
    Is this a proper 12vdc proportional solenoid ? - in that 6v is 50% position and 3v is 25% - making it more like a linear servo, than a conventional solenoid ?
    That part of the system sounds like a Voltage output DAC, which can be done on a Quickstart, with a few extra parts.
    What form does the flow sensor take ?
    How fast does the response need to be ?
  • sport270sport270 Posts: 82
    edited 2013-09-30 11:29
    it is a suar danfos h1 pump with automotive control
    i know that the highest voltage of the three is 4.26vdc at the correct flow.
  • sport270sport270 Posts: 82
    edited 2013-09-30 11:32
    on one of the circuits i had 34% duty cycle at 344hz = 4.26vdc
  • sport270sport270 Posts: 82
    edited 2013-09-30 11:34
    and thats using a high side Irf 4905 driver
  • Cluso99Cluso99 Posts: 18,069
    edited 2013-09-30 17:03
    You need to repost the question in the Propeller Forum (Prop 1)
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