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BS2 freezing — Parallax Forums

BS2 freezing

alnajjaralnajjar Posts: 12
edited 2005-06-20 13:44 in BASIC Stamp
I have an unpredictable behavior by a BS2 that activates a motor via a solid state relay.· the user activates the motor by pushing a button.· the motor moves an object a distance of about 5 feet and then is stopped by a magnetic switch.· The stamp controlls all this and it works very well.

but a weird things started happening, every 200 - 300 cycles of motor on / off the stamp freezes and will not operate normally until the power is turned off and then back on.

Is there a obvious diagnostic for such problems?· Does the stamp has a reputation for unpredictably freezing like I am describing above?

hope to get some insights...


Al

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-06-20 01:59
    No. The likely problem is a voltage sag or spike on the line is upsetting the BASIC Stamp.

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    Jon Williams
    Applications Engineer, Parallax
  • alnajjaralnajjar Posts: 12
    edited 2005-06-20 04:59
    That is a logical explanation!· I do have a 7805 with the appropriate capacitors.· Is there anything else I can do?

    Al
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-06-20 12:26
    In the world of small, reall-time microprocessors, there are few as reliable and simple to use as the BS2. No, what you are seeing is not typical of the BS2. What you are seeing is not uncommon in motor applications, where there's not enough power for the motor (leading to brown-outs, which reset the BS2), or not enough filtering of the power to the motor.

    I don't know how you are powering your solid-state relay, but some more capacitance there might help.

    Motor noise spikes on AC or DC lines can be unpredictable and cause the side-effects you are seeing.
    Appropriately sized (in voltage and capacitance) capacitors, appropriately positioned (across Vdd and Vss, across the motor power leads, and perhaps across the SSR)·can reduce this.
  • alnajjaralnajjar Posts: 12
    edited 2005-06-20 13:44
    This makes perfect sense! Now that I look carefuly at how this operates, the motor create a very noticeable brown-out when it is turned on. I tested that by pluging a light on the same circuit and the light looses half of its intensity. I wil plug the motor in a different circuit and see how that goes.

    Many thanks

    Al
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