Answer / chanchal

at first check the air supply.if it is ok then
feed the 4mA by using calibrator in i/p converter of positioner. if valve is zero position(fully closed) then its ok.if valve is not in zero position(fully closed) then set the zero position in positioner by using zero point screw.
next feed the 20mA by using calibrator in i/p converter of positioner.if valve is 100% open then its ok.if valve is not 100% open. then adjust the span setting by using span screwin positioner.
then check 25%,50%,and 75% open position in valve by feeding 8mA,12mA,and 16mA by using calibrator in same way.

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