8051 Microcontroller

T

Thread Starter

Tejas

Respected sir,

I made sequential timer using 8051 with four relay output. the problem is when relay is ON and OFF with time setted in program because of noise controller show the garbage value and working randomly.

with relay i run the solenoid valve of 220vAC. Please replay to remove the noise from the sytem. Is it software problem or Hardware?
 
Well, for to know if your problem is by hardward try remove the solenoid valve, let free the relay contact and try again, if the problem persist is a software problem.

If your problem is from hardware, you need to put a metal cover for your micro-controller circuit a conect it to earth. If the problem persist use SCR triac not relay.
 
Hello Tejas,

It's a common problem when you are trying to interface a discrete logic circuit with something like a Relay/Electrical Contactor/Solenoid etc... So the usual practice is to use a snubber circuit at the output... A snubber circuit is a combination of a Resistor, capacitor and a diode... The exact schematic can be had from internet... Just type snubber ckt and you'll get lots of websites... But Snubber circuit is a must...

Also proper earthing, as described in the earlier posting, is also necessary...

Rahul
[email protected]
 
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