PID control
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Do any of you who work in the marine industry know what considerations should be taken into account when using PID control for control valves in the chemical industry? Which aspects are mainly adjusted? What do integration and proportion mean in PID? On our end, we mainly adjust these two items. I am extremely grateful
PID control is generally used to regulate parameters such as pressure, temperature, level, and flow rate； P refers to the proportion, which is adjusted based on the magnitude of the deviation ； I is the integral, which is adjusted based on the presence of deviation.
Mnemonic: To set the parameters optimally, check in ascending order. Start with the proportional term, then the integral term, and finally add the derivative term. If the curve oscillates frequently, increase the proportional gain. If the curve wanders around in large swings, reduce the proportional gain. If the curve takes time to return to its normal position, decrease the integration time. If the curve’s fluctuations have a long cycle, extend the integration time further. If the oscillation frequency is high, first reduce the derivative term. Large errors lead to slow fluctuations. The differential time should be increased. For the ideal curve, there are two waves – higher at the beginning and lower at the end, in a 4-to-1 ratio. Observe carefully, make adjustments as needed, and conduct thorough analysis; this way, the quality of the adjustments will remain high