After long struggle thank God I was able to resolve the issue. The PCB design was changed such that pull up diode of pin 1 was connected close to the pin instead of having a routing such that it was passing on the PCB to a connecter ad connector was connected to a reset switch mounted on front panel. A capacitor of .1 mfd was also added and was connected to pin 1 to ground to filter noise.
I build a circuit to control pump. To run the pump certain conditions are to be met. This is all taken care by software. To operate pump a relay is switched on then after a determined time another relay is switched on. The first relay makes the pump in star and second relay changes it to delta. The pump is connected with contactors.
This PIC controller works fine as per required sequence when not connected to contactor relays. As soon as it is connected to operate relays it switches on the relay gives a pulse and gets reset. If interconnection cable is held in hand to form a shield it works ok. I changed the interconnection cable shielded type but it doesn’t work. The power used for microprocessor board and contactors relay is from two different transformers. This is to avoid any fluctuation on voltage. . Can any body suggest what causes system to get reset?
I build a circuit to control pump. To run the pump certain conditions are to be met. This is all taken care by software. To operate pump a relay is switched on then after a determined time another relay is switched on. The first relay makes the pump in star and second relay changes it to delta. The pump is connected with contactors.
This PIC controller works fine as per required sequence when not connected to contactor relays. As soon as it is connected to operate relays it switches on the relay gives a pulse and gets reset. If interconnection cable is held in hand to form a shield it works ok. I changed the interconnection cable shielded type but it doesn’t work. The power used for microprocessor board and contactors relay is from two different transformers. This is to avoid any fluctuation on voltage. . Can any body suggest what causes system to get reset?