Common problems during the commissioning of Siemens PS2 valve positioners

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Common problems during the commissioning of PS2 valve positioners: 1. Possible reasons why the positioner initialization stops at the first step; 2. Possible reasons why it stops at the second step; 3. Possible reasons why it stops at the third step. 4. An error message indicating free adjustment after the positioner initialization; 5. Possible reasons why the actual valve opening value keeps fluctuating around the set signal value after initialization; 6. A discrepancy between the set signal and the actual valve position after initialization. 7. After the positioner is initialized, the valve fails to achieve a \"tight closure\" state during operation. 8. Can a double-acting valve positioner be used with a single-acting valve? 9. ① How does the position feedback module output signals? ② The output signal of 3.8 mA does not change with the input signal; ③ No output signal is generated. 10 Answers to the questions: 1. ① Adjust the valve lever stroke to around 50%, or ensure that the valve position display shows a value between 45% and 55% (as indicated by the LCD display); ② The connection of the feedback linkage is loose; ③ The range setting is incorrect (33.). , 90°) Incorrect selection: ④ Insufficient air supply. 　　Answer to question 2: ① The valve position is not adjusted to be between 5–10% of the lower limit, or between 85–95% of the upper limit (displayed on the LCD); ② The feedback rod is loose. 　　Answer to question 3: If the valve actuator or the cylinder’s air capacity is too large, and the air supply to the positioner is insufficient, it is recommended to install a relay to increase the air supply speed. 　　Answer to question 4: Before making free adjustments, it is necessary to prepare a curve graph showing the relationship between the valve opening (flow rate) and the 20-point input signal. The ‘inflection points’ of this curve should not change significantly, otherwise errors are likely to occur. 　　Answer to question 5: ① The anti-inertia linkage is not tightly connected; ② There is excessive air leakage from the valve diaphragm or cylinder. 　　Answer to question 6: ① The action and reaction forces are set in opposite directions; ② The signal selection does not match the valve stem displacement; ③ The positioner dial has been moved; ④ Insufficient air supply; ⑤ It is in manual mode; ⑥ The feedback linkage is loose or disconnected. 　　Answer to Question 7: If the conversion is carried out on an old valve body, issues such as scale accumulation on the valve core or wear of the core may exist.
Answer to Question 8: Yes, but the other output port must be sealed.
Answer to Question 9: ① Connect a 24V DC power supply and connect it to the output circuit; ② The connection between the position feedback module of the actuator and the motherboard is not secure enough; ③ The polarity of the 24V DC power supply is reversed.