Harry Tenopoulos wrote:
>
> Hello everybody
>
> I have designed a PCB for the company i work for which is used on an
> automatic machine..
> The board has 3 PICs on it (2 16C54 and 1 16C55)
>
> This board interfaces with 3 external power relays.These relays are
> signaled from 3 other reed relays on the board which are
> opto-isolated from the signaling PIC.
>
> When the power relays operate alone (not connected to the machine's
> motor) there is no problem. But when they are connected problems
> start. These three relays control a two speed bi-directional  220V
> motor. At the change of speed or direction the electronic circuit
> seems to be reset (it happens about once in 10 changes).
>
> Can anyone tell me what is happening ?
>
> Harry
hi
 Can you not put a scope across the power pins it's best to know what
sort of noise you're being subject to.