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4thwatcher
04-06-2007, 06:04 PM
Hello everyboby, I'm a new member of this forum and I'm glad to be part of it. ·I'm a user of this basic stamp,·I have an·experience with electrical interfence with my basic stamp. I use the microcontroller to control the timing to stop a·machine and put it in its original position. What happen is when the board is install closed to other electrical parts like·motor starter·the board turns on randomly without pressing the stop botton. I was thinking of using microcontroller in replacement of PLC because it is cheaper. Is there a way to avoid this things to happen? thank you

QuattroRS4
04-06-2007, 08:51 PM
4thwatcher,
Circuit design is critical in such circumstances - the circuit board should employ ground planing - if you are switching inductive loads i.e. relays it is critical that safety measures are employed - reversed biased diodes across relay coils,contact suppression,filtering etc.In some circumstances shielding measures may be required.Try to employ optical coupling between devices (electrical isolation) where possible. Positioning of the device in the machine is critical try to avoid proximity to sources of noise.Cable routing is also critical.··A PLC is essentially a microcontroller circuit with these measures incorporated.

I posted these on a different thread - well worth a read.

http://forums.parallax.com/attachment.php?attachmentid=46338

http://forums.parallax.com/attachment.php?attachmentid=46339

Regards,
Quattro

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'Necessity is the mother of invention'

Post Edited (QuattroRS4) : 4/6/2007 1:14:22 PM GMT