Frequency converter constant pressure water supply control common problems and solutions - Database & Sql Blog Articles

1. The system pressure is unstable and easy to oscillate?
A: The system pressure is unstable, there may be several reasons:
A. There is a problem with the position of the pressure sensor collecting system pressure. The pressure collection point is selected too close to the water outlet of the pump, and the pipeline pressure is greatly affected by the water discharge speed. Therefore, the pressure value fed back to the controller is high and low, causing the system to oscillate.

B. In addition, if the system adopts the method of pressure tank, and the pressure collection point is selected on the pressure tank, it may cause oscillation of the system. Because the air itself has a certain degree of flexibility, and the solubility of the gas in the water changes, there is a certain time difference between the pump water and the pressure transmitted through the gas, causing the system to oscillate.

C, the acceleration and deceleration time of the controller and the inverter do not match the power of the pump motor. In general, the greater the power, the longer the acceleration and deceleration time. This parameter allows the user to select several more data for testing. For example, 15 kW is typically between 10 and 20 seconds.
2. Is the small pump starting and stopping too often?
Answer: In the system, the eleventh parameter in the controller's parameters, that is, the small pump stop pressure error is too small. After all main pumps are turned off, the small pump starts when the actual system pressure is lower than the set pressure. As the system pressure rises and the actual pressure of the system is higher than the sum of the set pressure and the small pump stop pressure error, the small pump is shut down by the system. Therefore, the solution to the problem is to increase the parameter to a certain value.

3. The analog output is not normal. The inverter running frequency does not match the controller output.
A: First of all, you should determine what hardware is wrong. The controller is put into the manual debugging state, and the analog output value corresponding to the controller output 0Hz and 50Hz is measured by the multimeter. If the analog output value of the controller is greater than 30mV at 0Hz, or less than the voltage value of the fifth parameter of the controller at 50Hz, there is a problem with the controller output. Here are a few things:
A. If the frequency of the controller changes, the output remains unchanged, indicating that the analog output circuit of the controller is damaged.
B. If the analog output value is also changed, but the maximum value cannot be reached, it can be solved by adjusting the VR3 potentiometer in the controller window.
Secondly, if the output value of the controller is normal, when the controller output reaches the maximum value, the inverter can not reach 50Hz, indicating that there is a problem with the set value of the inverter, and the frequency gain of the inverter can be adjusted.

4. When the pump is switched, the output of the inverter is not zero. Why?
Answer: The user should determine that the control line of the controller is connected to the inverter. When the pump performs the switching action, the controller will give the inverter a coasting stop signal, that is, the EMG signal. Some users of the EMG signal line are not connected, which directly leads to the above situation. Such phenomena must be absolutely prohibited, otherwise it will easily damage the inverter. If there is an EMG signal cable, please check carefully whether the wiring is connected. Make sure that there is no line fault, then use a multimeter to check if the controller's EMG has output. If the EMG signal is not output when the controller is in the switch, it is a problem with the controller.

5. How to connect the anti-interference wiring of the controller and the inverter?
Answer: In order to prevent the control signal line of the controller and the inverter from being interfered by the space electromagnetic field, the shield wire can be connected to the outer layer of these control signal lines to improve the anti-interference ability of the system. It must be noted that this type of wiring can only be selected for the grounding point of the shield. Whether on the side of the controller or on the side of the drive. In this way, the anti-interference ability of the system can be guaranteed. If the shielded wire is grounded at both ends, the potential difference will be generated on the shielded wire, which will not only improve the anti-interference ability of the system, but also increase the interference of the external controller.

6, the controller's data runs away, or the data is occasionally incorrect, how to solve?
A: This situation is caused by severe interference from the controller. Often the working environment of the controller is rather harsh, and the signal of interference comes from many aspects. After modifying the state or parameters of the controller, please turn the black keyboard lock switch in the controller window to the LOCK position. In this way, it is not only to prevent others from unintentionally modifying the parameters, but also to ensure that the system data does not fly. If the data is occasionally abnormal, the controller can automatically run without stopping, the system stability pressure has not changed, and the controller can automatically read the original data back. If the controller is not working properly, the user can disconnect the power of the controller. After a while, the system will resume normal operation. If the user forgets to lock the keyboard lock switch and the setting data is overwritten, the user needs to reset the system parameters. After the setting is completed, pay attention to the lock switch.

7. The contactor of the control motor has no action, and the motor does not start?
A: First look at the output status of the controller that the controller panel responds to, and compare the settings and operating indication status of the seven pumps on the panel described in the controller manual. If the indication status of the pump on the panel corresponding to the non-action motor has an output, the user first checks whether the external contactor wiring and the relay logic of the contactor are correct. If there is no problem, use a multimeter to measure the output of the corresponding relay of the controller. If the relay does not output a closed switch signal, there is a problem with the relay output of the controller. If there is no output indication for the corresponding pump indicated by the panel, please check the parameter setting of the controller to see if the corresponding pump is set to the on state (ON state).

8. The pressure sensor shows the pressure change, while the panel display pressure does not change?
A: First check the connection between the pressure sensor and the controller for loose or poor contact. If the above phenomenon does not exist, use a multimeter to measure the voltage value of the analog input port of the controller. First measure the voltage between the SV terminal and the GND terminal. If the voltage is 5V, it indicates that the power supply of the analog input port is normal. Then proceed to the next step. A 10K ohm sliding resistor can be connected to the three terminals of the input port of the controller, and the terminal is connected to P1, and then the voltage of the P1 terminal and the GND terminal of the controller is changed according to the resistance value of the resistor, if the P1 terminal is If the voltage at the GND terminal does not change, the analog output port of the controller is faulty or damaged. If it is normal, it means that it is a malfunction of the remote pressure gauge. Replace the pressure gauge.
9. When the system pressure is higher than the set value during work, why does the host not stop?
A: The main reason may be one of the following:

If the pressure of the pressure sensor does not match the pressure of the panel, but the pressure of the pressure sensor is higher than the set value, and the pressure reflected by the panel is not exceeded, check whether the pressure sensor is damaged and the wiring is faulty. At this point, the controller host is not normal.

If the above situation does not exist, the pressure of the controller and the sensor are consistent, and both are higher than the set pressure, then the setting state of the auxiliary small pump should be checked to see if the small pump is open. If the small pump is off, it is normal for the host to not stop. If the small pump is turned on, please check the operating frequency of the main pump. The lowest frequency is not the set value. This indicates that the system is in the normal water supply process.

10. The fire pump can't be patrolled regularly. Why?
A: First of all, check if the fire alarm timing inspection function of the controller has been turned on, and its function code is item 12. If this function is already on and the time value of the timed inspection is set, please check the record of the controller operation to see if there is any power failure of the controller. If the controller loses power during the running process, the controller will re-record the time, and when the time reaches the set inspection time, the inspection function will be performed.

11, the controller clock is running normally, but the control part has no output or the controller does not have any corresponding?
A: In this case, mainly the data in the controller has a serious error. There are mainly the following parameters: Item 6, the power value of the inverter has exceeded 200KW; in the seventh item, the acceleration/deceleration time of the inverter has exceeded 200 seconds; in the eighth item, the lower limit of the frequency exceeds 50Hz. After the above situation occurs, you can first disconnect the power of the controller, after a period of time (not less than 15 seconds), and then power up. At this point, the general system will return to normal. If the system is still intact, the data memory has been overwritten. Please reset the parameters to correct. After the modification is completed, please don't forget to turn the keyboard lock switch to the LOCK position.

12. How to use flow compensation and the difference between internal and external compensation?
A: Flow compensation is a compensatory measure used to stabilize the remote pipe network. The flow compensation of the C1 controller is divided into two methods: internal and external compensation. The main difference is that the internal compensation is the value calculated by the quadratic function determined by the curve of the pipe network flow loss when designing the controller program, and the final result is obtained by adding the normal analog output value of the controller. The speed of the water pump is controlled to achieve a control method that compensates for the pressure of the pipe network. The external compensation is controlled according to the value fed back from the externally connected flow meter, and after being converted, the result is superimposed with the normal output value of the controller. For specific internal compensation and external compensation wiring, please refer to the controller's manual or refer to the wiring method shown in the engineering drawings of this application guide.

13, the controller can not afford the pump, the RUN light flashes, why?
A: Because the controller is in a timed shutdown state. The user sets the controller's 16th function code to ON and specifies the time when the controller is powered on and off. At this time, the controller clock is in this period. Change the controller's 16th parameter.

14. What is the role of K2 in the controller?
Answer: Switch K2 is used as a controller expansion function, which is currently unavailable for users.
15. Communication error, how should the 08 phenomenon be solved?
A: First connect the communication line firmly. If the phenomenon remains, then judge whether the controller's host is still working normally. The method is to turn on the RUN/STOP and GND terminals of the controller, so that it is in the automatic running state, observe whether the RUN light on the controller main unit is on, and repeat it several times. If the RUN light changes accordingly, the controller main unit can still normal work. Otherwise, the controller is damaged. Please contact us.

16. The panel always displays P000. Why?
A: First, check that the controller's parameter settings are correct and check that the third parameter (the controller's pressure range) is set to zero. If it is non-zero, remove the control line of several terminals of the pressure sensor on the controller, and use a multimeter to measure whether the voltage between the SV terminal and the GND terminal is 5V DC. If it is normal, the panel should display the normal pressure range. Otherwise the controller is damaged. If the measured result is not 5V, the output power supply failure of the output analog is indicated.

17, the keyboard lock can not open, how to do?
A: Most of the reasons are the poor contact of the keyboard lock switch. You can push the keyboard lock switch up and down several times to push the switch into place. If not resolved, disconnect the power to the controller, drop a small amount of industrial alcohol into the black switch, and dial a few times. After the alcohol has evaporated, the power is tested. If it has not been resolved, the switch must be replaced.

18, cut the pump can not cut, what is going on?
A: If the pump is not completed every time the controller switches the signal, it indicates that there is a problem with the wiring of the external control logic. If the controller does not work in the normal operation of the controller, the controller is subject to strong interference. The user can check the line according to the anti-interference wiring method mentioned above, and the wiring of the controller can be modified as necessary.

19, 04 alarm, what should I do?
Answer: 04 alarm, indicating that the controller detects the water level signal, please check if there is any problem with the wiring of the water level sensor. If the wiring is normal, the wiring can be removed and the water level signal can be shorted with a short wiring. If the problem persists, the controller's water level detection section is faulty. Otherwise, the description is a problem with the water level sensor.
20. If there is only one water level signal in the system, how should the controller be wired?
A: At this time, the LA2 of the controller can be shorted and the water level signal is connected to LA1. At this time, attention should be paid to the type of signal provided by the water level sensor, and the correct access to the controller can make the system work normally.
21. The controller failed to change the pump at the set time interval. Why?
Answer: When the system pressure is stable and the pump does not switch, the controller should change the pump according to the set time interval. During this process, if a water pump switch occurs or if the machine stops midway, the pump's timed pump change time will be re-timed. If the pump fails to change at the set time interval, continuously monitor the controller. If the above mentioned conditions do not occur within the set time period, and there is no timing change, the controller is faulty.
22. When the feedback pressure is lower than the set pressure, what is the reason why the pump is not started for a long time?
A: In this case, please check the setting value of item 13 of the controller's setting parameters. This item is to set the controller's cut pump pressure error. In order to prevent the frequent start and stop of the pump, the allowable pressure is reduced by the set value minus the error value, and the set value plus the error value is within the upper bound range, and the pump does not start or stop or switch. Therefore, if the user feels that the controller does not start the pump for too long, this parameter should be set smaller.