A three-phase water pump speed control cabinet based on the DMX512 protocol

Abstract

The invention discloses a three-phase water pump speed control cabinet based on the DMX512 protocol, which includes: a DMX512 console, the DMX512 console is used to send a DMX512 control signal; a DMX512 signal decoder, the output channel of the DMX512 console is connected to the DMX512 signal input end of the DMX512 signal decoder, and the DMX512 signal decoder is used to decode the DMX512 control signal; a balancing module, the balancing module is used to balance the decoded signal output by the DMX512 signal decoder, so that the signal synchronization between each three-phase thyristor voltage regulating module is improved and the signal strength difference is reduced, so that each water pump motor correspondingly controlled by each three-phase thyristor voltage regulating module is in a synchronous state, and the three-phase water pump speed control cabinet based on the DMX512 protocol in the invention saves the frequency converter, thereby reducing harmonics, and also prevents the cable output by the frequency converter from generating great signal interference due to high-frequency power changes. The layout of electrical facilities is simplified, and no isolation transformer is required, so that safety is improved.

Description

Technical Field

[0001] The invention relates to the field of fountain control, and in particular to a three-phase water pump speed control cabinet based on a DMX512 protocol for fountain control. Background Art

[0002] The water pump is the carrier of "water", the most basic and important element in the fountain water show. At present, the working control of the motor of the three-phase 380V water pump in China is usually realized by the frequency converter. However, during the working process of the fountain water show, people actively or passively come into contact with the water body. In order to avoid the safety accidents related to the leakage of the fountain, one of the most important considerations for the safety of high-voltage electricity use is that the traditional frequency converter cannot be equipped with a leakage protector at the front end. Because when the traditional frequency converter is used, there are PWM (pulse width modulation) and PAM (pulse amplitude modulation) of the system, and the output is a high-frequency pulse voltage waveform exceeding several thousand Hz. The output voltage is a fast-changing pulse high-frequency voltage, which will generate a large number of harmonics. For the same motor and the same distributed capacitance of the three-phase power line, the leakage current will be greatly increased, causing the leakage protection switch to trip frequently. Therefore, most companies and manufacturers use isolation transformers at the front end of the frequency converter to protect personal safety. For example, the utility model with application number 201520502715.7 discloses a safety protection system for AC380V submersible pumps in a pool. A three-phase four-wire 380V AC power supply is used, and the secondary end of the three-phase isolation transformer is connected in sequence to the first leakage protector, the second leakage protector, the frequency converter and the three-phase AC motor of the submersible pump; the neutral line N of the AC power supply is directly grounded, and the casing of the submersible pump is connected to the neutral line N' of the secondary of the three-phase isolation transformer through a PU protection cable to form zero protection. The utility model uses a three-phase isolation transformer to separate the downstream system of the secondary side of the isolation transformer from the external power grid to avoid interference from the external power grid. The abnormal overvoltage shock of the external power grid can be released through the metal shielding layer connected to the ground to protect the insulation between the primary and secondary of the transformer. When an abnormality occurs and the system is electrically connected to the ground, the power supply will be triggered first to cut off the power supply to ensure that the leakage current passing through the human body is within a safe range to protect the lives of personnel.

[0003] However, the following problems were found during long-term use:

[0004] (1) The combination of the inverter and the isolation transformer is a huge burden in terms of both size and weight. Therefore, the traditional fountain water show control room often requires a relatively large area and special heat dissipation requirements. The control cabinet is also inconvenient to carry and install due to the combination of the inverter and the isolation transformer, and the signals between the cabinets interfere with each other.

[0005] (2) Because most AC power has one wire connected to the ground. There is a 220V potential difference between any phase line (live wire) and the ground. So people will get an electric shock when they touch the live wire. There is no electrical connection between the primary and secondary of the isolation transformer. Instead, the voltage is generated through electromagnetic induction. None of the three secondary wires are grounded. There is no potential difference between any secondary wire and the ground. So people will not get an electric shock when they touch any wire. However, if the waterproof construction of the cable is wrong, the wire is broken or bitten by an animal, etc., causing two or three wires at the output end of the isolation transformer to leak electricity at the same time, people who touch it will also get an electric shock due to the potential difference (380V) between different electrical phases, which is dangerous.

[0006] (3) In particular, in the existing PLC, the entire 0-5v or 0-10v or 0-20mA output signal is linearly controlled in the full range. However, in the special case of fountain control, the full range linear control will make it impossible to accurately control the signal range where the fountain often works, and a large amount of control resources will be wasted in the range where the fountain does not often work; what's more, in special situations such as the fountain is blocked or the fountain pipe bursts, the superiority of PLC control is not reflected.

[0007] The cable output by the frequency converter will produce great signal interference due to the high-frequency power changes. When a fountain water show uses a large number of high-pressure water pumps, the signal interference caused is even more difficult to estimate. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a three-phase water pump speed control cabinet based on the DMX512 protocol which is closely integrated with a fountain water pump.

[0009] The technical solution adopted by the present invention to solve the above problems is: the three-phase water pump speed control cabinet based on the DMX512 protocol includes: a DMX512 control console, the DMX512 control console is used to send a DMX512 control signal; a DMX512 signal decoder, the output channel of the DMX512 control console is connected to the DMX512 signal input end of the DMX512 signal decoder, and the DMX512 signal decoder is used to decode the DMX512 control signal; a balancing module, the balancing module is used to balance the decoded signal output by the DMX512 signal decoder, so that the signal synchronization between each three-phase thyristor voltage regulating module is improved. The signal strength difference is reduced, so that each water pump motor controlled by each three-phase thyristor voltage regulator module is in a synchronous state. The DMX512 signal decoder and the balance module are electrically connected through 0-5v; the three-phase thyristor voltage regulator module, the decoding output end of each DMX512 signal decoder is connected to the control signal input end of several three-phase thyristor voltage regulator modules, so that the decoded signal obtained after decoding the DMX512 control signal is sent to several three-phase thyristor voltage regulator modules; the water pump, the high-voltage output end of the three-phase thyristor voltage regulator module is connected to the power input end of the water pump, so that the motor of the water pump is controlled by the three-phase thyristor voltage regulator module. The DMX512 console can be a special DMX512 console or a host computer. The DMX512 console can control multiple DMX512 signal decoders, and each DMX512 signal decoder is set with an address. DMX512 signal decoders can be electrically connected to each other, so a DMX512 console controlling multiple DMX512 signal decoders can be connected to only one DMX512 signal decoder, saving DMX512 consoles.

[0010] As a preferred embodiment, in the three-phase water pump speed control cabinet based on the DMX512 protocol of the present invention, the balancing module includes a processor, a current detector, a voltage detector and a temperature sensor, the current detector, the voltage detector and the temperature sensor are all electrically connected to the analog signal input port of the processor, the processor is an ARM processor, and the DMX512 signal decoder is electrically connected to the analog signal receiving port of the processor. The processor can be connected to multiple current detectors, multiple voltage detectors, and multiple temperature sensors. The current detector detection is divided into a first type of current detector and a second type of current detector. The voltage detector is divided into a first type of voltage detector and a second type of voltage detector. The first type of current detector detects the current of each phase of the input three-phase thyristor voltage regulator module, the first type of voltage detector detects the voltage of each phase of the input three-phase thyristor voltage regulator module, the second type of current detector detects the current of each phase of the output three-phase thyristor voltage regulator module, the second type of voltage detector detects the voltage of each phase of the output three-phase thyristor voltage regulator module, and the temperature sensor detects the temperature of the three-phase thyristor voltage regulator module. The first type of current detector, the second type of current detector, the first type of voltage detector, the second type of voltage detector, and the temperature sensor are all electrically connected to the processor. The first type of current detector detects the current of each input phase, the first type of voltage detector detects the voltage of each input phase, the second type of current detector detects the current of each output phase, the second type of voltage detector detects the voltage of each output phase, the temperature sensor detects the temperature to prevent the three-phase thyristor voltage regulator module, and the three-phase thyristor voltage regulator module can be adjusted to prevent temperature drift, etc.

[0011] As a preferred embodiment, the three-phase water pump speed control cabinet based on the DMX512 protocol in the present invention is characterized in that: the control method of the processor is that the processor collects analog signals of the current detector, the voltage detector and the temperature sensor, and converts these signals into digital signals through the A / D module in the processor, and then stores the current detector signal in the memory variable Im, the voltage detector signal in the variable Um, the temperature sensor in the variable Tm, and the control signal output to the three-phase thyristor voltage regulating module in the variable Out, and then adjusts the control signal output to the three-phase thyristor voltage regulating module by a certain control method. The reason why the DMX512 signal decoder is not digitized here is that in an emergency, if the balancing module is broken, the analog signal of the DMX512 signal decoder can be directly connected to the three-phase thyristor voltage regulating module.

[0012] Preferably, the three-phase water pump speed control cabinet based on the DMX512 protocol in the present invention, the three-phase thyristor voltage regulating module includes a three-phase phase-shift trigger circuit, a unidirectional thyristor, an RC resistor-capacitor absorption circuit, a power supply circuit and a phase-shift voltage regulating module. The phase-shift voltage regulating module extracts the desired part from the original AC waveform according to the level of the control signal, and outputs after discarding the unwanted part. The three-phase phase-shift trigger circuit is responsible for managing the part of the power supply to control the continuous switching of the single-phase thyristor to turn on and off the circuit to output the desired waveform. The RC resistor-capacitor absorption circuit is responsible for absorbing the overvoltage and overcurrent surges caused by the intensive switching power supply to maintain the stability of the output circuit; the power supply circuit is responsible for supplying a stable power supply to the integrated circuit in the entire module.

[0013] As a preferred embodiment, in the three-phase water pump speed control cabinet based on the DMX512 protocol of the present invention, the output port of the DMX512 console is electrically connected to the D- and D+ terminals of the MX512 signal decoder, the 1-5V terminal of the MX512 signal decoder is electrically connected to the 1 terminal of the balancing module, the COM terminal of the MX512 signal decoder is electrically connected to the 3 terminal of the balancing module, the 2 terminal of the balancing module is electrically connected to the 0-10V port of the three-phase thyristor voltage regulator module, and the 4 terminal of the balancing module is electrically connected to the COM terminal of the three-phase thyristor voltage regulator module. The control voltage port of the three-phase thyristor voltage regulator module is the 0-10V port, and the output voltage of the DMX512 signal decoder is 0-5v. Because there is redundancy in the design, the three-phase thyristor voltage regulator module is generally not allowed to operate at full power, and generally operates at low power, so the DMX512 signal decoder can be connected to the three-phase thyristor voltage regulator module only in an emergency.

[0014] As a preferred embodiment, in the three-phase water pump speed control cabinet based on the DMX512 protocol of the present invention, the current detector is a current transformer, and the voltage detector is a voltage transformer. The current transformer and the voltage transformer are simple to use and can be directly connected to the analog port of the ARM processor, which is convenient to use.

[0015] Preferably, in the three-phase water pump speed control cabinet based on the DMX512 protocol of the present invention, the DMX512 console and the DMX512 signal decoder are connected through a 3-pin interface, the first pin is GND, the second pin is D-, the third pin is D+, and there is a differential signal between D- and D+, and the DMX512 console and the DMX512 signal decoder are serial communication. Serial differential communication can have a strong ability to resist electromagnetic interference and achieve accuracy of data transmission.

[0016] As a preferred embodiment, the three-phase water pump speed control cabinet based on the DMX512 protocol in the present invention is powered by three-phase electricity, and the three-phase wires L1, L2, and L3 are all connected to the leakage protector, and then connected to the leakage protector AC contactor, and then connected to the three-phase thyristor voltage regulating module. The use of DMX512 can directly connect the leakage protector, which is convenient and safe, unlike the original combination of a frequency converter and an isolation transformer. The volume and weight of the three-phase water pump speed control cabinet based on the DMX512 protocol in this embodiment are greatly reduced, which is convenient for installation in the control room and saves a lot of heat dissipation equipment.

[0017] Compared with the prior art, the present invention has the following advantages and effects: the three-phase water pump speed control cabinet based on the DMX512 protocol in the present invention eliminates the frequency converter, thereby reducing harmonics, and also prevents the cable output by the frequency converter from generating great signal interference due to high-frequency power changes. The layout of electrical facilities is simplified, and no isolation transformer is required, so that safety is improved. Due to errors in cable waterproofing construction, wire skin breakage or animal biting, two or three wires at the output end of the isolation transformer leak electricity at the same time. If people come into contact with it, they will also get electric shock due to the potential difference (380V) between different electrical phases. The danger caused is controlled by using a DMX512 console, and the mapping relationship between the control range of the control voltage and the instruction code is adjusted, so that it is more matched with the use status of the fountain and the adjustment accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a wiring connection diagram of multiple three-phase water pump speed control cabinets according to an embodiment of the present invention.

[0019] Figure 2 The present invention is a wiring connection diagram of a three-phase water pump speed control cabinet.

[0020] Figure 3 It is a partial structural wiring connection diagram of a three-phase water pump speed control cabinet according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0022] See also Figure 1-Figure 3, the three-phase water pump speed control cabinet based on the DMX512 protocol includes: a DMX512 console, a DMX512 signal decoder, and a balancing module. In this embodiment, the three-phase water pump speed control cabinet based on the DMX512 protocol and the water pump constitute a three-phase water pump speed control system based on the DMX512 protocol. The DMX512 console is used to send DMX512 control signals; the output channel of the DMX512 console is connected to the DMX512 signal input end of the DMX512 signal decoder, and the DMX512 signal decoder is used to decode the DMX512 control signal; the balancing module is used to balance the decoded signal output by the DMX512 signal decoder, so that the signal synchronization between each three-phase thyristor voltage regulating module is improved and the signal strength difference is reduced. Small, so that each water pump motor controlled by each three-phase thyristor voltage regulator module is in a synchronous state, and the DMX512 signal decoder and the balance module are electrically connected through 0-5v; three-phase thyristor voltage regulator module, the decoding output end of each DMX512 signal decoder is connected to the control signal input end of several three-phase thyristor voltage regulator modules, so that the decoded signal obtained after decoding the DMX512 control signal is sent to several three-phase thyristor voltage regulator modules; water pump, the high-voltage output end of the three-phase thyristor voltage regulator module is connected to the power input end of the water pump, so as to control the motor of the water pump through the three-phase thyristor voltage regulator module. The DMX512 console can be a special DMX512 console or a host computer. The DMX512 console can control multiple DMX512 signal decoders, and each DMX512 signal decoder is set with an address. DMX512 signal decoders can be electrically connected to each other, so a DMX512 console controlling multiple DMX512 signal decoders can be connected to only one DMX512 signal decoder, saving DMX512 consoles.

[0023] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the balancing module includes a processor, a current detector, a voltage detector and a temperature sensor. The current detector, the voltage detector and the temperature sensor are all electrically connected to the analog signal input port of the processor. The processor is an ARM processor, and the DMX512 signal decoder is electrically connected to the analog signal receiving port of the processor. The processor can be connected to multiple current detectors, multiple voltage detectors, and multiple temperature sensors. The current detector detection is divided into a first type of current detector and a second type of current detector. The voltage detector is divided into a first type of voltage detector and a second type of voltage detector. The first type of current detector detects the current of each phase of the input three-phase thyristor voltage regulator module, the first type of voltage detector detects the voltage of each phase of the input three-phase thyristor voltage regulator module, the second type of current detector detects the current of each phase of the output three-phase thyristor voltage regulator module, the second type of voltage detector detects the voltage of each phase of the output three-phase thyristor voltage regulator module, and the temperature sensor detects the temperature of the three-phase thyristor voltage regulator module. The first type of current detector, the second type of current detector, the first type of voltage detector, the second type of voltage detector, and the temperature sensor are all electrically connected to the processor. The first type of current detector detects the current of each input phase, the first type of voltage detector detects the voltage of each input phase, the second type of current detector detects the current of each output phase, the second type of voltage detector detects the voltage of each output phase, the temperature sensor detects the temperature to prevent the three-phase thyristor voltage regulator module, and the three-phase thyristor voltage regulator module can be adjusted to prevent temperature drift, etc.

[0024] The three-phase water pump speed control cabinet based on the DMX512 protocol in this embodiment is characterized in that: the control method of the processor is that the processor collects analog signals of the current detector, voltage detector and temperature sensor, and converts these signals into digital signals through the A / D module in the processor, then stores the current detector signal in the memory variable Im, stores the voltage detector signal in the variable Um, stores the temperature sensor in the variable Tm, and stores the control signal output to the three-phase thyristor voltage regulator module in the variable Out, and then adjusts the control signal output to the three-phase thyristor voltage regulator module through a certain control method. The reason why the DMX512 signal decoder is not digitized here is that in an emergency, if the balancing module is broken, the analog signal of the DMX512 signal decoder can be directly connected to the three-phase thyristor voltage regulator module.

[0025] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the three-phase thyristor voltage regulation module includes a three-phase phase-shift trigger circuit, a unidirectional thyristor, an RC resistor-capacitor absorption circuit, a power supply circuit and a phase-shift voltage regulation module. The phase-shift voltage regulation module extracts the desired part from the original AC waveform according to the level of the control signal, and discards the unwanted part before outputting it. The three-phase phase-shift trigger circuit is responsible for managing the part of the power supply to control the continuous switching of the single-phase thyristor to turn on and off the circuit to output the desired waveform. The RC resistor-capacitor absorption circuit is responsible for absorbing the overvoltage and overcurrent surge phenomena caused by the intensive switching power supply to maintain the stability of the output circuit; the power supply circuit is responsible for supplying a stable power supply to the integrated circuits in the entire module.

[0026] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the output port of the DMX512 console is electrically connected to the D- and D+ terminals of the MX512 signal decoder, the 1-5V terminal of the MX512 signal decoder is electrically connected to the 1 terminal of the balancing module, the COM terminal of the MX512 signal decoder is electrically connected to the 3 terminal of the balancing module, the 2 terminal of the balancing module is electrically connected to the 0-10V port of the three-phase thyristor voltage regulator module, and the 4 terminal of the balancing module is electrically connected to the COM terminal of the three-phase thyristor voltage regulator module. The control voltage port of the three-phase thyristor voltage regulator module is the 0-10V port, while the output voltage of the DMX512 signal decoder is 0-5v. Because there is redundancy in the design, the three-phase thyristor voltage regulator module is generally not allowed to operate at full power, and generally operates at low power. Therefore, the DMX512 signal decoder can only be connected to the three-phase thyristor voltage regulator module in an emergency.

[0027] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the current detector is a current transformer, and the voltage detector is a voltage transformer. The current transformer and the voltage transformer are simple to use and can be directly connected to the analog port of the ARM processor, which is convenient to use.

[0028] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the DMX512 console and the DMX512 signal decoder are connected through a 3-pin interface, the first pin is GND, the second pin is D-, the third pin is D+, and there is a differential signal between D- and D+. The DMX512 console and the DMX512 signal decoder are serial communication. Serial differential communication can have a strong ability to resist electromagnetic interference and achieve accuracy of data transmission.

[0029] In the three-phase water pump speed control system based on the DMX512 protocol in this embodiment, the water pump is powered by three-phase electricity, and the three-phase wires L1, L2, and L3 are all connected to the leakage protector, then connected to the leakage protector AC contactor, and then connected to the three-phase thyristor voltage regulator module. Using DMX512, the leakage protector can be directly connected, which is convenient and safe, unlike the original combination of a frequency converter and an isolation transformer. The volume and weight of the three-phase water pump speed control system based on the DMX512 protocol in this embodiment are greatly reduced, which is convenient for installation in the control room and saves a lot of heat dissipation equipment.

[0030] The control cabinet of this embodiment is provided with a balancing module, which has the following advantages: the balancing module can detect the power input in real time. If there is a phase loss, overvoltage, low voltage, etc. in the power input, the output can be stopped and displayed on the screen at the front of the chassis. If everything is normal, the voltage of the power input and the current total current will be displayed. The balancing module can detect the output voltage and current of the independent module in real time, and can adjust the control voltage according to the actual output status so that all modules can output the same voltage under the same DMX512 value. At the same time, the parameters of different motors can be manually input, and the output can be cut off to protect the motor when the motor is over-current, overspeed or stalled. The balancing module can detect the working temperature of the three-phase voltage regulating module in real time, and automatically stop the output to protect the module if there is overtemperature. The balancing module can manually set and adjust the output voltage curve to achieve the purpose of linear control of the three-phase water pump.

[0031] The above contents described in this specification are merely examples of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, as long as they do not deviate from the contents of the present specification or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A three-phase water pump speed control cabinet based on DMX512 protocol, characterized in that include: DMX512 controller, DMX512 controller is used to send DMX512 control signals; DMX512 signal decoder, the output channel of the DMX512 console is connected to the DMX512 signal input terminal of the DMX512 signal decoder, and the DMX512 signal decoder is used to decode the DMX512 control signal; Balance module, the balance module is used to balance the decoded signal output by the DMX512 signal decoder; Three-phase thyristor voltage regulating module, the decoding output end of each DMX512 signal decoder is connected to the control signal input end of several three-phase thyristor voltage regulating modules, so that the decoded signal obtained after decoding the DMX512 control signal is sent to several three-phase thyristor voltage regulating modules; The high-voltage output end of the three-phase thyristor voltage regulating module is connected to the power input end of the water pump, so that the motor of the water pump is controlled to work through the three-phase thyristor voltage regulating module; The balancing module includes a processor, a current detector, a voltage detector and a temperature sensor. The current detector, the voltage detector and the temperature sensor are all electrically connected to the analog signal input port of the processor. The processor is an ARM processor. The DMX512 signal decoder is electrically connected to the analog signal receiving port of the processor. The current detector detection is divided into a first type of current detector and a second type of current detector. The voltage detector is divided into a first type of voltage detector and a second type of voltage detector. The first type of current detector detects the current of each phase input into the three-phase thyristor voltage regulator module. The first type of voltage detector detects the voltage of each phase input into the three-phase thyristor voltage regulator module. The second type of current detector detects the current of each phase output from the three-phase thyristor voltage regulator module. The second type of voltage detector detects the voltage of each phase output from the three-phase thyristor voltage regulator module. The temperature sensor detects the temperature of the three-phase thyristor voltage regulator module.

2. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The control method of the processor is that the processor collects the analog signals of the current detector, the voltage detector and the temperature sensor, and converts these signals into digital signals through the A / D module in the processor, then stores the current detector signal into the memory variable Im, stores the voltage detector signal into the variable Um, stores the temperature sensor into the variable Tm, stores the control signal output to the three-phase thyristor voltage regulating module into the variable Out, and then adjusts the control signal output to the three-phase thyristor voltage regulating module.

3. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The three-phase thyristor voltage regulator module includes a three-phase phase-shift trigger circuit, a unidirectional thyristor, an RC resistor-capacitor absorption circuit, a power supply circuit and a phase-shift voltage regulator module. The phase-shift voltage regulator module extracts the desired part from the original AC waveform according to the level of the control signal, and discards the unwanted part before outputting it. The three-phase phase-shift trigger circuit is responsible for managing the part of the power supply to control the continuous switching of the single-phase thyristor to turn on and off the circuit to output the desired waveform. The RC resistor-capacitor absorption circuit is responsible for absorbing the overvoltage and overcurrent surge phenomena caused by the intensive switching power supply to maintain the stability of the output circuit; the power supply circuit is responsible for supplying a stable power supply to the integrated circuit in the entire module.

4. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The output port of the DMX512 console is electrically connected to the D- and D+ terminals of the MX512 signal decoder, the 1-5V terminal of the MX512 signal decoder is electrically connected to the 1 terminal of the balancing module, the COM terminal of the MX512 signal decoder is electrically connected to the 3 terminal of the balancing module, the 2 terminal of the balancing module is electrically connected to the 0-10V port of the three-phase thyristor voltage regulating module, and the 4 terminal of the balancing module is electrically connected to the COM terminal of the three-phase thyristor voltage regulating module.

5. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The current detector is a current transformer, and the voltage detector is a voltage transformer.

6. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The DMX512 console and the DMX512 signal decoder are connected via a 3-pin interface, the first pin is GND, the second pin is D-, the third pin is D+, and there is a differential signal between D- and D+. The DMX512 console and the DMX512 signal decoder are in serial communication.

7. The three-phase water pump speed control cabinet based on DMX512 protocol according to claim 1 is characterized in that: The water pump is powered by three-phase electricity, and the three-phase wires L1, L2, and L3 are all connected to the leakage protector, then connected to the leakage protector AC contactor, and then connected to the three-phase thyristor voltage regulating module.

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