The basic error parameter control valve supplier shall request the valve dead zone parameters and power / gas valve positioner control valve. In general, the dead zone parameters of the valve should not exceed 2%, the basic error distribution / gas valve positioner control valve should be less than ± 10%, if equipped with digital valve positioner, the control valve should be less than the basic error of ± 1% .

It should be noted on the air control valve pressure requirements. According to the actual situation of the device, check the control valve actuators for instrument air pressure requirements. If the device does not meet the requirements of instrument air pressure actuators, the valve actuator supplier should be replaced at the same time, provide high-quality instrument air, at least should meet the following requirements: clean, dry and does not contain obvious corrosive impurities, the gas containing solid particles is less than 0.1g / m 3, particle diameter of not more than 3 μ m, an oil content not greater than 1 × 10 (-6 th power), according to statistics, because air is not clean cause locator does not work case the total failure rate of the positioner 60% or more.