Full-automatic constant-pressure water supply control device

Abstract

The utility model provides a full-automatic constant-pressure water supply control device which comprises a programmable logic controller (PLC), a button switch, two frequency converters, a constant-pressure water supply controller, an intermediate relay, an alternating-current contactor, an indicator light and a working pump. The PLC is respectively connected with the frequency converters, the button switch, the frequency converters, the constant-pressure water supply controller, the intermediate relay, the alternating-current contactor and the indicator light. The constant-pressure water supply controller and the pressure sensor accurately detect the water pressure of the output pipeline, output analog quantity control signals to the frequency converter and control the output frequency of the frequency converter, so that closed-loop control over the water pressure of the output pipeline is achieved, automatic control over the water pressure is achieved, and stability of the water pressure is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of full-automatic constant-pressure water supply, and particularly relates to a full-automatic constant-pressure water supply control device. Background Art

[0002] With the progress of technology, industrial control equipment has gradually changed from the original relay control method to programmable control, controlled by single-board computers, numerical control systems, etc. The control system is becoming more and more intelligent and user-friendly. In this regard, the products of Siemens are the most advanced and reliable. The old relay control has poor flexibility, versatility and high failure rate. In order to meet the technical requirements of electrical design and electrical maintenance brought about by this development, a set of full-automatic constant-pressure water supply control device is studied to meet the equipment control requirements. Content of the Utility Model

[0003] The utility model aims to solve the problems of poor operation stability and reliability of the old water supply system, thereby providing a full-automatic constant-pressure water supply control device to ensure the constancy of the system pressure and improve the reliability of the water supply equipment.

[0004] To achieve the above-mentioned utility model purpose, the utility model provides a full-automatic constant-pressure water supply control device, which is characterized in that: it includes a PLC, a push-button switch, two frequency converters, a constant-pressure water supply controller, an intermediate relay, a contactor, an indicator light, and a working pump. The PLC is respectively connected to the frequency converter, the push-button switch, the frequency converter, the constant-pressure water supply controller, the intermediate relay, the contactor, and the indicator light;

[0005] The frequency converter selection switch K1 is connected to the input terminals I0.0 and I0.1 of the PLC, and the selection method of the frequency converter is input to the input terminals I0.0 and I0.1 of the PLC. After being judged by the internal program of the PLC, the intermediate relays ZJ1-ZJ4 respectively connected through the output terminals Q0.0-Q0.3 are used to select the operation of the first frequency converter or the second frequency converter and drive the first pump to work or the second water pump to work;

[0006] The working pump includes a first pump and a second pump. The working pump selection switch K2 is connected to the input terminals I0.2 and I0.3 of the PLC, and the selection method signal of the working pump is input to the input terminals I0.2 and I0.3 of the PLC. After logical operation by the internal program of the PLC, the intermediate relays ZJ6 and ZJ7 respectively connected through the output terminals Q0.5 or Q0.6 act to give corresponding frequency conversion operation signals to control the operation of the corresponding frequency converter;

[0007] The first push-button SB1 is connected to the input terminal I0.4 of the PLC, and the start-stop signal of the first pump is input to the input terminal I0.4 of the PLC, driving the corresponding contactor to attract, connecting the frequency converter to the corresponding water pump motor to drive the water pump to operate;

[0008] The second button SB2 inputs the start / stop signal of the second pump to the input terminal I0.5 of the PLC, drives the corresponding AC contactor to close, connects the frequency converter to the corresponding water pump motor, and drives the water pump to operate;

[0009] The constant pressure water supply controller is connected to the pressure sensor in the water supply pipeline. It compares the collected pressure value with the set pressure value and outputs a current signal to the analog input terminal of the frequency converter, adjusts the analog current value between 4 - 20 mA output to the frequency converter, changes the frequency of the variable frequency output of the frequency converter, controls the speed of the water pump motor, and ensures the constant pressure of the system pipeline.

[0010] Further, the normally open auxiliary contact of the AC contactor is connected to the corresponding input port of the PLC and the operating indicator light of the frequency converter.

[0011] Further, the normally open contacts of the internal fault output relays of the frequency converters respectively close the corresponding relays when faults occur in the two frequency converters, send the fault alarm signal to the input terminals I0.6 and I0.7 of the PLC. After internal logical operations, a fault alarm signal is sent from the corresponding fault output terminals Q1.0 or Q1.1 of the PLC to drive the corresponding signal indicator lights to emit the fault alarm signal.

[0012] The fully automatic constant pressure water supply control system, through reasonable program design, and through the precise detection of the water pressure of the output pipeline by the constant pressure water supply controller and the pressure sensor, outputs an analog control signal to the frequency converter, controls the output frequency of the frequency converter, realizes the closed-loop control of the water pressure of the output pipeline, realizes the automatic control of the water pressure, and ensures the stable water pressure. The device has strong versatility, stable performance, and great popularization value. Description of the Drawings

[0013] Figure 1 It is the PLC electrical schematic diagram of the two - source water supply pump;

[0014] Figure 2 It is the electrical schematic diagram of the two - source water supply pump;

[0015] Figure 3 It is the electrical schematic diagram of the control terminals of the No. 1 frequency converter;

[0016] Figure 4 It is the electrical schematic diagram of the control terminals of the No. 2 frequency converter;

[0017] Figure 5 It is the electrical schematic diagram of the control circuit of the two - source water supply pump;

[0018] Figure 6 It is the electrical schematic diagram of the main control circuit of the two - source water supply pump. Detailed Implementation Modes

[0019] To better understand the purpose, structure, and function of the present utility model, the following further describes in detail a fully automatic constant pressure water supply control device of the present utility model in conjunction with the attached drawings.

[0020] Referring to Figure 1 , this device uses a Siemens S7-200 PLC as the main control element. 1. This element has strong expandability, reliable operation, simple programming, and can design and allocate input and output ports according to user needs. 2. After editing the program using a dedicated programming software, the programmed control program is downloaded into the PLC using a dedicated programming cable. 3. The edited program is monitored online using the monitoring method provided by the programming software, and unreasonable parts in the program are found and modified accordingly until the control program is stable and reliable.

[0021] This device uses a DH-9000A type constant pressure water supply control unit. This element can compare the 4-20ma current signal collected by the pressure transmitter with the pressure value given by the user through the internal CPU control unit, and output analog signals to supply two Fuji inverters respectively, for controlling the output frequency of the inverter to achieve the constancy of the system pressure.

[0022] This device uses a Fuji FRENIC 5000P11 / 75KW inverter drive control element, which has powerful functions, can perform variable frequency drive on the motor, achieve variable frequency control, is flexible in application, compact in structure, safe and reliable, and is especially suitable for use in intelligent automatic control.

[0023] This device uses a pressure transmitter to collect the signal of the output pipeline pressure of the water supply system. The obvious feature of the pressure transmitter is its durability and high reliability.

[0024] The mechanical drive uses a three-phase AC asynchronous motor, and the advantages of the motor are reliable operation, economy, and practicality.

[0025] Figures 1 to 6 This is the electrical schematic diagram of the device, and the following is the analysis of this schematic diagram.

[0026] (1) Figure 1 It is the PLC input unit

[0027] Using the DC 24v power supply provided inside the PLC, through external buttons, selector switches, normally open contacts of the internal fault relay of the inverter, and normally open contacts of each AC contactor, corresponding information is collected into the PLC, and after internal logical operations, logical information is sent out to make corresponding controls through the output end.

[0028] Figure 2 It is the control circuit of the main contactors of the first and second water pumps and the indication circuit for the operation of the first inverter or the second inverter.

[0029] Figure 3 It is a PLC output unit that drives the corresponding intermediate relay indicator lights through the output status of this unit, and drives the water pump motor to operate and issue fault indicators by driving the corresponding control circuit.

[0030] Figure 4 It is for the wiring of the control input terminal of the first water pump inverter and the selection of the control source of the given frequency signal, as well as the wiring of the pressure sensor signal input of the constant pressure water supply controller, and the connection principle between the output signal and the inverter.

[0031] Figure 5 It is for the wiring of the control input terminal of the first water pump inverter and the selection of the control source of the given frequency signal, as well as the wiring of the pressure sensor signal input of the constant pressure water supply controller, and the connection principle between the output signal and the inverter.

[0032] Figure 6 It is the main circuit diagram of the constant pressure water supply control system. This diagram details the control from the main power supply to the inverter and from the inverter to the main circuit of the AC contactor to control two water pump motors to achieve a control method of one in use and one standby.

[0033] The fully automatic constant pressure water supply control device includes a PLC, push-button switches, two inverters, a constant pressure water supply controller, intermediate relays, AC contactors, indicator lights, and working pumps. Among them, the PLC is respectively connected to the inverters, push-button switches, inverters, constant pressure water supply controller, intermediate relays, AC contactors, and indicator lights.

[0034] Through the above connections,

[0035] 1: Use the inverter selection switch K1 to input the selection method of the inverter to the input terminals I0.0 and I0.1 of the PLC. After being judged by the internal program of the PLC, select the operation of the first inverter or the second inverter and drive the first pump or the second water pump to work through the intermediate relays ZJ1 - ZJ4 respectively connected to the output terminals Q0.0 - Q0.3.

[0036] 2: The working pumps include the first pump and the second pump. Use the working pump selection switch K2 to input the selection method signal of the working pump to the input terminals I0.2 and I0.3 of the PLC. After logical operation by the internal program of the PLC, the intermediate relays ZJ6 and ZJ7 respectively connected to the output terminals Q0.5 or Q0.6 act to give the corresponding frequency conversion operation signal to control the operation of the corresponding inverter.

[0037] 3: The start / stop signal of Pump 1 is input to the input terminal I0.4 of the PLC through the first button SB1. The PLC makes a logical judgment based on the input status of the input terminal and outputs corresponding signals to control the actions of relevant relays, driving the corresponding AC contactors to close, connecting the frequency converter to the corresponding water pump motor to drive the water pump to operate.

[0038] 4: The start / stop signal of Pump 2 is input to the input terminal I0.5 of the PLC through the second button SB2. The PLC makes a logical judgment based on the input status of the input terminal and outputs corresponding signals to control the actions of relevant relays, driving the corresponding AC contactors to close, connecting the frequency converter to the corresponding water pump motor to drive the water pump to operate.

[0039] 5: When a fault occurs in the two frequency converters, the normally open contacts of the internal fault output relays of the two frequency converters respectively cause the corresponding relays to close, sending a fault alarm signal to the input terminals I0.6 and I0.7 of the PLC. After internal logical operations, a fault alarm signal is sent from the corresponding fault output terminals Q1.0 or Q1.1 of the PLC to drive the corresponding signal indicator lights, making the corresponding fault indicator lights light up to send a fault alarm signal.

[0040] 6: The normally open auxiliary contact of the AC contactor for the operation of Pump 1 of the first frequency converter is connected to the input terminal I1.0 and the operation indicator light of the first frequency converter. When it is closed, a feedback signal is input to the input terminal I1.0 of the PLC to monitor the operation status of Pump 1 motor.

[0041] 7: The normally open auxiliary contact of the AC contactor for the operation of Pump 1 of the second frequency converter is connected to the input terminal I1.1 and the operation indicator light of the second frequency converter. When it is closed, a feedback signal is input to the input terminal I1.1 of the PLC to monitor the operation status of Pump 1 motor.

[0042] 8: The normally open auxiliary contact of the AC contactor for the operation of Pump 2 of the first frequency converter is connected to the input terminal I1.2 and the operation indicator light of the first frequency converter. When it is closed, a feedback signal is input to the input terminal I1.2 of the PLC to monitor the operation status of Pump 2 motor.

[0043] 9: The normally open auxiliary contact of the AC contactor for the operation of Pump 2 of the second frequency converter is connected to the input terminal I1.3 and the operation indicator light of the second frequency converter. When it is closed, a feedback signal is input to the input terminal I1.3 of the PLC to monitor the operation status of Pump 2 motor.

[0044] The constant pressure water supply controller is connected to the pressure sensor in the water supply pipeline. It compares the collected pressure value with the set pressure value and outputs a current signal to the analog input terminal of the frequency converter, adjusts the analog current value between 4-20ma output to the frequency converter, changes the frequency of the variable frequency output of the frequency converter, controls the speed of the water pump motor, ensures the constant pressure of the system pipeline, and achieves the purpose of constant pressure water supply.

Claims

1. An automatic constant pressure water supply control device, characterized in that: It includes a PLC, pushbutton switches, two inverters, a constant pressure water supply controller, intermediate relays, AC contactors, indicator lights, and working pumps. The PLC is respectively connected to the inverters, pushbutton switches, inverters, constant pressure water supply controller, intermediate relays, AC contactors, and indicator lights. The inverter selection switch K1 is connected to the input terminals I0.0 and I0.1 of the PLC, and the selection method of the inverter is input to the input terminals I0.0 and I0.1 of the PLC. After judgment through the internal program of the PLC, the intermediate relays ZJ1 - ZJ4 respectively connected through the output terminals Q0.0 - Q0.3 are used to select the operation of the first inverter or the second inverter; and drive the operation of the first pump or the second water pump. The working pumps include a first pump and a second pump. The working pump selection switch K2 is connected to the input terminals I0.2 and I0.3 of the PLC, and the selection method signal of the working pump is input to the input terminals I0.2 and I0.3 of the PLC. After logical operation through the internal program of the PLC, the intermediate relays ZJ6 and ZJ7 respectively connected through the output terminal Q0.5 or Q0.6 act to give corresponding frequency conversion operation signals to control the operation of the corresponding inverters. The first pushbutton SB1 is connected to the input terminal I0.4 of the PLC, and the start / stop signal of the first pump is input to the input terminal I0.4 of the PLC, driving the corresponding AC contactor to close, connecting the inverter to the corresponding water pump motor to drive the water pump to operate. The second pushbutton SB2 inputs the start / stop signal of the second pump to the input terminal I0.5 of the PLC, driving the corresponding AC contactor to close, connecting the inverter to the corresponding water pump motor to drive the water pump to operate. The constant pressure water supply controller is connected to the pressure sensor in the water supply pipeline. It compares the collected pressure value with the set pressure value and outputs a current signal to the analog input terminal of the inverter, adjusts the analog current value between 4 - 20 mA output to the inverter, changes the frequency of the inverter's variable frequency output, controls the speed of the water pump motor, and ensures the constant pressure of the system pipeline.

2. The automatic constant pressure water supply control device according to claim 1, characterized in that: The auxiliary normally open contact of the AC contactor is connected to the corresponding input port of the PLC and the inverter operation indicator light.

3. The fully automatic constant pressure water supply control device according to claim 1, characterized in that: The normally open contacts of the internal fault output relays of the inverters respectively close the corresponding relays when faults occur in the two inverters, and send fault alarm signals to the input terminals I0.6 and I0.7 of the PLC. After internal logical operation, fault alarm signals are sent at the corresponding fault output terminals Q1.0 or Q1.1 of the PLC to drive the corresponding signal indicator lights to emit fault alarm signals.

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