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Prevent Basic Stamp from electric noise — Parallax Forums

Prevent Basic Stamp from electric noise

markustermarkuster Posts: 184
edited 2007-08-11 19:26 in BASIC Stamp
Hi,

Sometimes Stamps don't work fine when
there is some AC ,DC motors or
refrigerator pumps , etc. near them.

How can I avoid these kind of problems ?

I tried to keep Stamp more than 3 feet distance from
motors but that it is not enough.

Perhaps you know some other tricks or ideas to solve
that, and use B.Stamps in industrial enviroments
where there is a lot of noise.

Thanks, Mark

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-11 18:07
    Optically isolate the connections to the device generating the noise. Use an isolated power supply. Use filtering on the power supply to reduce P/S noise. Finally you could shield the BASIC Stamp within a grounded metal enclosure. Take care.

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    Chris Savage
    Parallax Tech Support
  • markustermarkuster Posts: 184
    edited 2007-08-11 18:35
    Thanks

    I am not an expert, sorry.

    About your suggestions , thanks, but I don't understand this,
    I apreciate if you have a little example of this points:

    1--Use filtering on the power supply to reduce P/S noise.
    (How can I do that ? , do you have more info., please )

    2--Use an isolated power supply.
    ( Do yo have an example? )

    3--Optically isolate the connections to the device generating the noise.
    ( How can insolate the conections to the device? )

    4-- Finally you could shield the BASIC Stamp within a grounded metal enclosure:
    ( No problem about this point 4 , I understood ) ( My problem is 1,2 and 3.

    Thanks, Mark
    PS: Perhaps there are to many questions but I am can't solve the problem
    from about 3 weeks. I will apreciate your help.
  • Mike GreenMike Green Posts: 23,101
    edited 2007-08-11 18:48
    3) Read the "Industrial Control" tutorial that you can download from the Stamps in Class section of the Parallax website, particularly Experiment #2 and #3.

    2) In this case, it would help just to have a separate power supply for the Stamp and its immediate surrounding circuitry. This supply should be AC powered and the AC circuit should be separate from the one powering the motors, etc. if possible.

    1) Extra filtering could just be in the form of a large electrolytic capacitor in parallel with the power supply terminals (like 1000uF to 3000uF). You can put a small inductor (say 1uH) in series with the positive lead from the supply to the capacitor. Look at the schematic for the Propeller Protoboard for an example of this sort of filtering for use with servo motors.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-11 19:26
    Mark,

    I will see if I can elaborate on what I meant…

    1) Filtering could be as simple as some capacitors on the VDD/VSS lines. It could be a choke/inductor. It really depends on the type of noise.

    2) An isolated supply could mean using batteries or something separate from the supply the noise generating devices are using since noise can feed back into the power supply.

    3) Optical Isolation is pretty straight forward. Electrical noise can sometimes come through the control line. Using an opto to drove the device will eliminate electrical noise from that part of the circuit.

    I hope this helps. Take care.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
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