When using Huichuan frequency converters (such as MD280, MD500, etc.) for constant pressure water supply, PID control function is usually required to adjust the pump speed in real time through pressure sensor feedback. The following are the general setup steps (please refer to the corresponding model manual for specific parameters):
**1、 Basic parameter settings**
1. * * Motor parameter settings**
-P0.01: Motor control mode (usually choosing V/F or vector control)
-P0.03: Rated power (kW)
-P0.04: Rated voltage (V)
-P0.05: Rated current (A)
-P0.06: Rated frequency (Hz, usually 50Hz)
-P0.07: Rated speed (r/min)
2. * * Run command source**
-P0.17: Set to 1 (terminal control) or 2 (panel control), choose according to actual needs.
3. * * Frequency source selection**
-P0.18: Set to 6 (PID control) and enable PID adjustment function.
**2、 PID parameter setting**
1. * * PID target value setting**
-P10.00: PID target value (set constant pressure target pressure, for example, 0.4MPa needs to be converted to the corresponding analog value, if 0-10V corresponds to 0-1.0MPa, set it as 4V or 40%).
2. * * PID feedback signal selection**
-P10.01: PID feedback source (e.g. set to 1, indicating AI1 terminal connected to pressure sensor).
3. PID parameter adjustment**
-P10.02: Proportional gain (P-value, initially set to 0.5-2.0, adjusted according to response)
-P10.03: Integral time (I value, initially set to 5-20 seconds)
-P10.04: Differential time (D value, usually set to 0 or smaller)
4. * * PID output characteristics**
-P10.05: PID action direction (usually set to 0, increase frequency when feedback value is lower than target).
**3、 Pressure sensor calibration**
1. Confirm the range of the pressure sensor (such as 4-10MPa corresponding to 4-20mA or 0-10V).   
2. Set analog input parameters:
-P6.00 (AI1 input type): Select based on sensor signal (e.g. 0-10V set as 1, 4-20mA set as 2).   
-P6.01 (AI1 lower limit corresponding value): The voltage/current value corresponding to 0MPa.   
-P6.02 (AI1 upper limit corresponding value): The voltage/current value corresponding to 1.0MPa.
**4、 Sleep and wake-up function (optional)**
1. * * Sleep frequency**
-P11.00: Set the sleep frequency (such as 30Hz, below which the pump will stop after a certain period of time).   
2. * * Awaken stress**
-P11.01: Wake up deviation (such as restarting when the pressure is lower than the target value of 0.1MPa).
**5、 Protection parameter settings**
1. Overvoltage and undervoltage protection (P2 group parameters).   
2. Overcurrent protection (P3 group parameters).   
3. Pump idle protection (optional, set low-frequency limit P1.05, such as 20Hz).
**6、 Debugging steps**
1. Complete wiring: Connect the pressure sensor to the AI terminal, and connect the output of the frequency converter to the water pump motor.   
2. After setting the basic parameters, first test whether the motor direction is correct without load.   
3. Gradually increase the pressure and observe whether the PID regulation is stable. Adjust the P and I parameters to eliminate oscillations or delays.   
4. Test whether the sleep/wake function is normal.
**Precautions**
-The pressure sensor needs to be installed on the outlet pipeline of the water pump to avoid vibration interference.   
-If the system oscillates (with large pressure fluctuations), the P value can be reduced or the I value can be increased.   
-When multiple pumps are connected in parallel, a rotation function needs to be configured. Please refer to the multi pump control settings in the manual for details.
Suggest operating according to the specific model manual, and if necessary, contact our technical support to obtain a parameter list!