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Electronic noise, difficult to understand Please Help. — Parallax Forums

Electronic noise, difficult to understand Please Help.

JoeJoe Posts: 184
edited 2010-11-17 05:16 in BASIC Stamp
Hi,

I have a Basic Stamp 2 module near a contactor ( A big relay "K1" )
and each time the contactor is ON or OFF the Basic Stamp
reset.

The distance between the Contactor and the Basic Stamp is
5 inches and there is no electric contact between them.

The Basic stamp power supply I am using is very good ( 12 VDC, industrial , more than
$ 200 )

I tried more Basic Stamps and all have the same problem.

Please see the picture.

Thanks. Joe
DIAGRAM-BS.jpg
322 x 488 - 27K

Comments

  • bill190bill190 Posts: 769
    edited 2010-11-16 17:16
    Electrical "noise" can travel through the air.

    A good example of this is to turn on the AM radio in your car to a weak station, then drive under high power electrical lines and you will hear noise on your radio. Even though the lines are high in the air.

    This is called EMI...
    http://en.wikipedia.org/wiki/Electromagnetic_interference

    The solution to the "air" part of this problem is to surround the electronic device with grounded metal or in a metal can/container. Then the noise does not get through. Like this...
    http://e-fab.com/images/circuit-board-shielding.jpg

    And wires or circuit board traces can act as an "antenna" to this noise. So a solution to that is to use "shielded cable" which has a grounded metal outer layer like this...
    http://www.l-com.com/images/cat6-shield-drain-wire.jpg

    The shielding / metal surround is like a Faraday Cage...
    http://en.wikipedia.org/wiki/Faraday_cage
  • wiresalotwiresalot Posts: 40
    edited 2010-11-16 17:21
    Whats the voltage, frequecy, and amperage running thru the contactor?
  • hover1hover1 Posts: 1,929
    edited 2010-11-16 18:29
    Does the BS2 Power Supply AND the Relay share the same 110VAC line?

    Jim
  • electrosyselectrosys Posts: 212
    edited 2010-11-17 02:33
    If it's possible (at your circuit's electrical load) you could try with a solid state relay
    which decrease the electrical noise when switching.
  • stamptrolstamptrol Posts: 1,731
    edited 2010-11-17 05:16
    Is there a suppressor on the coil of the relay? Its also sometimes required that a RC suppressor be used on the contacts of the relay to kill high frequency noise during switching.
    Is the programming cable connected to the stamp? It takes very little interference to toggle the reset line.
    It may also be necessary to separate the two devices physically or shield them from one another.
    Finally, even with a good power supply, a 0.1 uF or so capacitor right at the Stamp's 5 volt pins is a good practice.
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