thanks all again>
i tryed to put EMI filter on main control supply, but the problem still there, i supplied PIC through shotky diod and put many 100nF capacitor and nothing changed >
what do you mean in a non-isolated circuit ??Originally Posted by Melanie
between my PIC and contacter there is an opto-coupler and small relay , the power supply of (opto-coubler transister) is different for my pic power supply with different transformer and different GND , is this the isolation you mean !!
is the noise from heater contacter make all the problem through main supply or through air to the board ??
if i take the board supply (220v) from another location and didnt connect it with the same heater supply will solve this noise problem ???
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