1. Fix the pneumatic actuator on the calibration platform, connect the air source, control air source and displacement detection connecting rod respectively; adjust the instrument on the calibration platform accurately;
2. Mechanical zero calibration: input 4mA current signal (0 %), the control gas signal should be 0.02Mpa, at this time the cylinder piston stroke should be zero; if it is not zero, the zero point can be adjusted by adjusting the nut on the zero adjustment screw (the zero point is higher than the tightening nut); the zero point and range are required Repeated adjustment; zero point error should be ≤1%;
3. Mechanical full-scale calibration: input 20mA current signal (100%), control gas signal should be 0.10Mpa, at this time the cylinder piston stroke should be the upper limit; if it is not the upper limit The range can be adjusted by adjusting the tension of the range tension spring (the range is smaller, the tension spring is loose, and the range is larger, the tension spring is larger); the zero point and the range need to be adjusted repeatedly; the full-scale error should be ≤1%;
4. The midpoint of the mechanical range Positioning: After adjusting the zero point and range, input a 12mA current signal (50%, 0.06Mpa), and adjust the position of the position transmitter connecting rod to keep it perpendicular to the horizontal plane at this point;
5. Full stroke deviation calibration: input Control gas signal 0.02Mpa (0%), then gradually increase the input signal 0.036 Mpa (20%), 0.052 Mpa (20%), 0.068 Mpa (60%), 0.084 Mpa (80%), 0.1 Mpa (100%), Make the cylinder piston complete the stroke, and the deviation of each point must be ≤1.5%;
6. Non-linear deviation test: input the control gas signal 0.02Mpa (0%), then gradually increase the input signal until 0.10Mpa (100%), and then change the signal Decrease to 0.02Mpa (0%), make the actuator complete the stroke, and record the stroke value corresponding to the signal pressure of each increase or decrease of 0.008Mpa. The actual pressure-the nonlinear deviation between the stroke relationship and the theoretical value should be ≤1 %; ※
7. Positive and negative stroke variation test: Same as the non-linear deviation test method. In the actual positive and negative pressure-stroke relationship, the maximum difference between the positive and negative stroke values of the cylinder piston under the same air pressure value should be ≤1%.
