Anyone can make program to compare to number to operate relay

Anyone can make program to compare two numbers
.and if variable value exceed contstant value then relay come into low state

if(variable > constant) relay_state = LOW;

DKWatson:

if(variable > constant) relay_state = LOW;

Or, more directly:

  if (variable > Constant) digitalWrite(RelayPin, LOW);

(I use initial capitals to help me keep track of which identifiers are global and which identifiers are local.)

Fair enough. Either solution though, fits with the rest of the code.