Automatic rotating speed control system for normal-temperature floating ring sealing test based on PLC (Programmable Logic Controller)

Abstract

The invention relates to a normal-temperature floating ring sealing test rotating speed automatic control system based on a PLC, and belongs to the technical field of test bed rotating speed automatic adjustment controlled by the PLC. The upper configuration is used for transmitting set operation parameters and target values to the data transmission subsystem; the test data measurement subsystem is used for measuring and obtaining a rotating speed value and a power value in a test process; the rotating speed value and the power value are forwarded to a PLC control subsystem through a data transmission subsystem; the PLC control subsystem is used for outputting a rotating speed control signal and sending the rotating speed control signal to the rotating speed adjusting subsystem; receiving an operation state and current and voltage data transmitted by the rotating speed adjusting subsystem; sending to an upper configuration for display; the rotating speed adjusting subsystem adjusts the rotating speed of the test device according to the rotating speed control signal; the problems that manual rotation speed adjustment is complex in operation, the test process is time-consuming, manual judgment of multiple parameters is time-consuming and labor-consuming, and the system automation level is low are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic speed regulation of a test bench controlled by a PLC, and relates to a normal temperature floating ring seal test speed automatic control system based on a PLC. Background Art

[0002] The floating ring seal structure is a heavy pressure component in the rocket engine turbopump. It relies on the gap between the floating ring and the rotor after the rotor is started to form a dynamic pressure film, thereby achieving the function of sealing and throttling.

[0003] The working performance of the floating ring also determines the safety and reliability of the rocket engine and is a key component that affects the success or failure of the rocket launch.

[0004] At present, the floating ring component test bench mainly relies on the motor-driven speed increaser to drag the test device to complete various sealing test tasks.

[0005] The rotation speed, as the core parameter of the test, is an important basis for verifying the sealing performance of the floating ring.

[0006] To ensure the smooth progress of the test, the speed is controlled to reach the rated value in a step-by-step manner, that is, it is started at a low speed, and the speed is increased after the system runs smoothly and all parameters are tested to be normal, and the rated speed is gradually reached to avoid damage to the floating ring product and the test equipment due to complex working conditions during direct high-speed starting, so as to reduce the test risk.

[0007] The traditional floating ring seal test bench speed control system has the following problems: the test process needs to control the speed according to parameters such as power, vibration, flow, etc. The traditional test bench uses manual methods to complete the speed input, confirmation, verification, operation, modification and other operations. At the same time, the test personnel need to focus on monitoring dozens of measurement parameters such as speed during the test process. The complicated operation and monitoring work distracts the test personnel's energy, increases the burden on the test personnel, and easily causes test failures due to human negligence. Summary of the invention

[0008] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a PLC-based normal temperature floating ring seal test speed automatic control system, which solves the problems of complex manual speed adjustment operation, time-consuming test process, time-consuming and labor-intensive manual judgment of numerous parameters, and low system automation level.

[0009] The solution of the present invention is:

[0010] The PLC-based normal temperature floating ring seal test speed automatic control system includes upper configuration, PLC control subsystem, test data measurement subsystem, data transmission subsystem, and speed regulation subsystem;

[0011] Upper configuration: transmit the set operating parameters and target values ​​to the data transmission subsystem;

[0012] Test data measurement subsystem: measure the speed value and power value during the test; send the speed value and power value to the data transmission subsystem;

[0013] Data transmission subsystem: receives the operating parameters and target values ​​from the upper configuration, and sends the operating parameters and target values ​​to the PLC control subsystem; receives the speed value and power value from the test data measurement subsystem, and sends the speed value and power value to the PLC control subsystem;

[0014] PLC control subsystem: receiving operating parameters, target values, speed values, and power values ​​from the data transmission subsystem; using the operating parameters, target values, speed values, and power values ​​as input values, inputting the preset PLC speed program, outputting speed control signals, and sending the speed control signals to the speed regulation subsystem; receiving operating status and current and voltage data from the speed regulation subsystem; judging whether there is a fault based on the operating status, and sending the operating status to the upper configuration display if there is no fault; generating alarm information and sending it to the upper configuration display if there is a fault; sending current and voltage data to the upper configuration display for monitoring;

[0015] Speed ​​regulation subsystem: Receives the speed control signal from the PLC control subsystem, and adjusts the speed of the test device according to the speed control signal; monitors the current and voltage during the test, and sends the operating status and current and voltage to the PLC control subsystem.

[0016] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the upper configuration display content includes the main screen, program control screen, flow control screen, parameter setting screen, alarm record, and flow chart.

[0017] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the program control screen includes two speed control modes, namely free control mode and program control mode; among them, the free control mode is to control the speed manually; the program control mode is to realize automatic adjustment of the speed in sections according to the set value.

[0018] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the test data measurement subsystem includes a data collector and a field sensor;

[0019] Among them, the data acquisition device connects to various sensors at the test site, collects real-time signals from the sensors, and records them; the field sensors include temperature transmitters, mass flow meters, pressure transmitters, speed measurement modules, power measurement modules, and vibration sensors; the field sensors use a two-wire signal transmission method, and each measurement channel is equipped with a signal isolator.

[0020] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the data transmission subsystem adopts Ethernet mode to interconnect different subsystems with the test device; realizes sending the signals recorded by the data collector to the upper configuration; and realizes data transmission between the upper configuration and the PLC control subsystem through the OPC communication protocol.

[0021] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the OPC communication protocol adopts dual network redundancy for data transmission to ensure the stability of data transmission.

[0022] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the speed regulation subsystem includes: a frequency converter, a variable frequency motor, a filter, an output reactor and an encoder.

[0023] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the PLC control subsystem obtains the gear box temperature signal, motor speed signal, and power signal measured by the temperature transmitter, speed measurement module, and power measurement module respectively, which are used for the control program of the test device speed; the PLC control subsystem obtains the pipeline flow and pressure signals measured by the mass flow meter and pressure transmitter respectively, which are used to control the opening of the pipeline valve; the PLC control subsystem controls the start and stop of the inverter in the speed adjustment subsystem and the change of the inverter control mode through buttons.

[0024] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the PLC control subsystem realizes data communication with the frequency converter in the speed regulation subsystem via Ethernet.

[0025] In the above-mentioned PLC-based normal temperature floating ring seal test speed automatic control system, the control process of the speed automatic control system is:

[0026] S1. Confirm whether the system status is normal; the normal system status includes no fault alarm in each subsystem, normal connection and setting of the on-site sensor, and normal display of the upper configuration screen; otherwise, the system status is abnormal and the test is stopped;

[0027] S2. Determine the speed control mode and set the system parameters according to the test conditions;

[0028] S3. If the control mode is free control mode, set the acceleration and deceleration time, time, torque limit and speed in the free control mode interface, confirm the system status and start the main motor;

[0029] S4. If the control mode is program control mode, set the number of cycles, target speed for each section, acceleration and deceleration time for each section, duration for each section, and torque limit for each section in the program control mode interface, confirm the system status and start the main motor;

[0030] S5. Start the system interlock protection function; the interlock protection function includes gearbox temperature protection function, gearbox vibration protection function and power over-limit protection function;

[0031] S6. Determine whether the auxiliary equipment of the motor and the gearbox of the test bench are in operation and start the test; the auxiliary equipment of the gearbox of the test bench includes the fan of the test bench and the oil cooler of the test bench.

[0032] The beneficial effects of the present invention compared with the prior art are:

[0033] (1) The present invention can continuously monitor the operating status of the test system, process parameters and test parameters of the floating ring product, and generate records and alarm information, so that the entire test process is in a visualized, controllable and safe operation mode;

[0034] (2) The present invention monitors and logically judges key parameters in the test system to avoid distracting the operator's attention, and realizes automatic control of the speed through logical judgment, which reduces the operation time, improves the test efficiency, and enhances the automation level of the system;

[0035] (3) The present invention can set up to seven speed control programs, and use a step-by-step increasing method to control the speed to reach the rated value, thereby avoiding damage to the floating ring product and the test device due to complex working conditions during direct high-speed startup, thereby reducing the risk of test failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the automatic control system of the normal temperature floating ring seal test speed based on PLC of the present invention;

[0037] Figure 2 This is a network topology diagram of a normal temperature floating ring seal test speed automatic control system based on PLC according to an embodiment of the present invention;

[0038] Figure 3 This is a configuration diagram of the PLC control subsystem of an embodiment of the present invention;

[0039] Figure 4 This is a diagram of the overall functional architecture of the upper configuration of an embodiment of the present invention;

[0040] Figure 5This is a control diagram of the upper configuration program of an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments.

[0042] The present invention provides a PLC-based normal temperature floating ring seal test speed automatic control system, which solves the problems in the prior art of complex manual speed adjustment, time-consuming test process, time-consuming and labor-intensive manual judgment of numerous parameters, and low system automation level.

[0043] PLC-based automatic control system for the speed of floating ring seal test at room temperature, such as Figure 1 As shown, it specifically includes upper configuration, PLC control subsystem, test data measurement subsystem, data transmission subsystem, and speed regulation subsystem.

[0044] Upper-level configuration: Transmit the set operating parameters and target values ​​to the data transmission subsystem.

[0045] The upper configuration display content includes the main screen, program control screen, flow control screen, parameter setting screen, alarm record, and flow chart.

[0046] The program control screen includes two speed control modes, namely free control mode and program control mode; among them, the free control mode is to control the speed manually; the program control mode is to automatically adjust the speed in sections according to the set value.

[0047] Test data measurement subsystem: measures the speed and power values ​​during the test; sends the speed and power values ​​to the data transmission subsystem.

[0048] The test data measurement subsystem includes a data collector and field sensors. The data collector connects to various sensors at the test site, collects real-time signals from the sensors, and records them; the field sensors include temperature transmitters, mass flow meters, pressure transmitters, speed measurement modules, power measurement modules, and vibration sensors; the field sensors use a two-wire signal transmission method, and each measurement channel is equipped with a signal isolator.

[0049] Data transmission subsystem: receives the operating parameters and target values ​​from the upper configuration, and sends the operating parameters and target values ​​to the PLC control subsystem; receives the speed value and power value from the test data measurement subsystem, and sends the speed value and power value to the PLC control subsystem.

[0050] The data transmission subsystem uses Ethernet mode to interconnect different subsystems with the test device; it sends the signals recorded by the data collector to the upper configuration; and it realizes data transmission between the upper configuration and the PLC control subsystem through the OPC communication protocol.

[0051] The OPC communication protocol uses dual network redundancy for data transmission to ensure stable data transmission.

[0052] PLC control subsystem: Receives operating parameters, target values, speed values, and power values ​​from the data transmission subsystem; uses the operating parameters, target values, speed values, and power values ​​as input values, inputs the preset PLC speed program, outputs a speed control signal, and sends the speed control signal to the speed regulation subsystem; receives operating status and current and voltage data from the speed regulation subsystem; determines whether there is a fault based on the operating status, and if there is no fault, sends the operating status to the upper configuration display; if there is a fault, generates an alarm message and sends it to the upper configuration display; sends the current and voltage data to the upper configuration display for monitoring.

[0053] The PLC control subsystem obtains the gear box temperature signal, motor speed signal, and power signal measured by the temperature transmitter, speed measurement module, and power measurement module respectively, which are used for the control program of the speed of the test device; the PLC control subsystem obtains the pipeline flow and pressure signals measured by the mass flow meter and pressure transmitter respectively, which are used to control the opening of the pipeline valve; the PLC control subsystem controls the start and stop of the inverter in the speed adjustment subsystem and the change of the inverter control mode through buttons.

[0054] The PLC control subsystem realizes data communication with the frequency converter in the speed regulation subsystem through Ethernet.

[0055] The PLC control subsystem adopts a distributed control mode, using Siemens S7-1500 series CPU1515 as the control master station and ET200SP as the control substation.

[0056] Speed ​​regulation subsystem: Receives the speed control signal from the PLC control subsystem, and adjusts the speed of the test device according to the speed control signal; monitors the current and voltage during the test, and sends the operating status and current and voltage to the PLC control subsystem.

[0057] The speed regulation subsystem includes: frequency converter, variable frequency motor, filter, output reactor and encoder.

[0058] The control process of the speed automatic control system is:

[0059] S1. Confirm whether the system status is normal; the normal system status includes no fault alarm in each subsystem, normal connection and setting of the on-site sensor, and normal display of the upper configuration screen; otherwise, the system status is abnormal and the test is stopped.

[0060] S2. Determine the speed control mode and set the system parameters according to the test conditions.

[0061] S3. If the control mode is free control mode, set the acceleration and deceleration time, time, torque limit and speed in the free control mode interface, confirm the system status and start the main motor.

[0062] S4. If the control mode is program control mode, set the number of cycles, target speed for each section, acceleration / deceleration time for each section, duration for each section, and torque limit for each section in the program control mode interface, confirm the system status and start the main motor; in program control mode, different speed control parameters can be set in each section as needed, and up to seven speed control programs can be set.

[0063] S5. Start the system interlock protection function; the interlock protection function includes gearbox temperature protection function, gearbox vibration protection function and power overlimit protection function.

[0064] S6. Determine whether the auxiliary equipment of the motor and the gearbox of the test bench are in operation and start the test; the auxiliary equipment of the gearbox of the test bench includes the fan of the test bench and the oil cooler of the test bench.

[0065] Example

[0066] The embodiment provides a PLC-based automatic control system for the rotation speed of a normal temperature floating ring seal test, such as Figure 1 As shown, it includes upper configuration, PLC control subsystem, test data measurement subsystem, data transmission subsystem, and speed adjustment subsystem, among which, the upper configuration is used to monitor the system status and test process data, set system operation parameters and target values, and send data to the PLC control subsystem; the test data measurement subsystem is used to measure and record test data, and process the data; the data transmission subsystem is used for data transmission between subsystems and devices; the PLC control subsystem obtains various measurement parameters through the data transmission subsystem, generates control signals to adjust the output of the frequency converter, and controls the opening and closing of various valves in the process system; the speed adjustment subsystem receives the instructions of the PLC control subsystem, controls the motor to drive the gear box, and thus realizes the speed adjustment function of the test device.

[0067] The test data measurement subsystem provided in the embodiment of the present invention can be divided into a test data measurement subsystem and a vibration data measurement subsystem according to the measurement function, wherein the test data measurement subsystem includes an industrial computer, a data collector, a sensor and a test cable, and its data collector adopts Gantner's data acquisition module A108, which meets the measurement capability of 30 channels. In order to realize communication with the entire system, a communication module Q101 is configured, which has an Ethernet interface and data output function; the vibration data measurement subsystem includes a host computer, a vibration data collector, a three-axis acceleration sensor and a test cable. Its vibration data collector uses DEWESoft's SIRIUS 8HD module, which can simultaneously collect multiple three-axis vibration acceleration sensor signals and perform real-time FFT analysis.

[0068] The field sensor provided by the embodiment of the present invention includes a mass flow meter, a speed measurement module, a temperature transmitter, a pressure transmitter module, a power measurement module and a vibration sensor. Among them, the mass flow meter is used to measure the leakage of the floating ring product outlet, and this parameter is one of the important indicators for verifying the performance of the floating ring. The mass flow meter uses the Micro Motion CMF series, and the accuracy can reach 0.5%. The speed measurement module is used to measure the speed of the floating ring product, and the speed adjustment subsystem is controlled according to the measured speed parameter to realize the automatic control of the speed. The speed parameter is also one of the important indicators for verifying the performance of the floating ring. The temperature transmitter is used to measure the system temperature parameters, including the floating ring product temperature, the oil cooler temperature and the gearbox temperature, wherein the gearbox temperature is used for the interlocking protection function to prevent the gearbox from having an accident due to excessive temperature during the test. The pressure transmitter is used to measure the pressure of helium, air and nitrogen in the pipeline or device, monitor the medium supply during the test, and the PLC control subsystem adjusts the medium supply in real time according to the pressure measurement value. The power measurement module monitors the process status of the speed adjustment subsystem to ensure that the system operates within the safety threshold range. The vibration sensor, including a three-axis vibration acceleration sensor, a vibration measuring cable and an installation module, is used to measure the vibration value of each point in the X / Y / Z directions, monitor the vibration of the system, and ensure the safe and stable operation of the system.

[0069] The field sensor adopts a two-wire 4-20mA signal transmission method, and each measurement channel is equipped with a signal isolator to ensure the anti-interference of signal transmission.

[0070] The data transmission subsystem provided in the embodiment of the present invention is used for data transmission between various subsystems and devices, such as Figure 2As shown, it includes communication between PLC and host computer, communication between PLC master station and substation, communication between PLC and inverter, communication between test data collector and host computer, and communication between vibration data collector and host computer. Among them, data intercommunication is realized between PLC and host computer through OPC communication protocol. OPC protocol is the interface standard of hardware and software used in the field of industrial control and production automation. It proposes the interface standardization between equipment and application programs of different manufacturers to simplify the data exchange between them. PLC and inverter exchange data through modbus protocol, which is a mainstream serial communication protocol, widely used in various controllers, and used to communicate with peripheral devices.

[0071] like Figure 3 As shown in the figure, the PLC control subsystem adopts a distributed control mode, using Siemens S7-1500 series CPU1515 as the control master station and ET200SP as the control substation. The control master station is arranged in the operation console, connected to the button switch through the digital I / O module to realize the remote control function of the operation console; connected to the host computer through the configured communication interface to realize the data exchange function. The control substation is installed in the test site transfer box, connected to the valve at the test site through the digital I / O module to control the opening and closing of the valve, connected to some sensors at the test site through the analog I / O module to obtain the measurement signals required for automatic control, and realize data communication with the frequency converter through Ethernet.

[0072] The PLC control subsystem adopts the TIA Portal V17 platform for programming, which has the advantages of convenient programming and high reliability.

[0073] The control program can be decomposed into 8 subroutines, namely, input subroutine, parameter processing subroutine, fault and alarm processing subroutine, transmission control subroutine, flow and valve control subroutine, other auxiliary equipment control subroutine, output subroutine, and simulation subroutine, among which:

[0074] Input subroutine to read the operation data of the inverter, including status word, motor speed, motor current, motor torque, motor power, motor voltage and other parameters; for status monitoring of other input physical addresses.

[0075] The parameter processing subroutine is used for multi-speed setting processing in the program control screen.

[0076] The fault and alarm processing subroutine is used to handle system faults and alarms, output action emergency stop signals, screen fault alarms, etc.

[0077] The transmission control subroutine can realize functions including judging the comprehensive start / stop signal, manual and automatic selection processing, multi-speed processing in automatic mode, conversion between terminal speed and motor speed, etc.

[0078] Flow and valve control subroutines are used for collecting flow meter data and controlling regulating valves.

[0079] Other auxiliary equipment control subroutines are used to control the operation of motor fans, start and stop of oil coolers, remote closing of frequency converter cabinets, equipment power supply control and other functions.

[0080] The output subroutine is used to map global variables to actual output physical addresses and write inverter data, including control words, speed setting, acceleration and deceleration time, torque limit, etc.

[0081] The simulation subroutine can cut off the output connection and run the debugging simulation program.

[0082] The main functions of the upper configuration provided by the embodiment of the present invention include test information entry, PLC control, process interface display and control, equipment configuration function, data acquisition real-time display and recording function, and data playback function. The software adopts a multi-threaded parallel execution design architecture, such as Figure 4 As shown. The test information entry mainly includes filling in the file name, product number, model and other information of the test product; the PLC control function establishes communication between the PLC and the computer. The software can obtain the status parameters of the PLC and other related equipment in real time, and can write the control signal into the PLC to realize the control of peripheral equipment such as valves and motors; the process interface display and control, including the main screen, program control screen, flow control screen, parameter setting screen, alarm record, flow chart, and can control the start and stop of the measurement system, such as Figure 5 As shown; Equipment configuration function, including Gantner acquisition equipment configuration, Modbus & OPC configuration, virtual channel configuration; The real-time display function of data acquisition not only displays data in the form of a table on the process interface, but also has a waveform display function, which not only has the function of displaying real-time values, but also has a cursor display function; The data playback function can automatically or manually load TDMS data files, and you can easily browse the data collected by each channel by simply dragging and dropping.

[0083] In the embodiment, the speed regulation subsystem includes a frequency converter, a variable frequency motor, a filter, an output inductor and an encoder. According to the power design requirements, the variable frequency motor uses ABB's QABP series motor, and the frequency converter uses ABB's ACS880 series. At the same time, in order to balance the distributed capacitive load of the outgoing cable, increase the short-circuit impedance of the outgoing main circuit, and suppress the harmonics output by the frequency converter, a matching output inductor is added after the output end of the frequency converter.

[0084] An embodiment of the present invention provides a method for automatically controlling the rotation speed of a normal temperature floating ring seal test based on PLC, and the specific steps include:

[0085] (1) Confirm that the control console and frequency converter cabinet are not in emergency stop state;

[0086] (2) Confirm that the test system has no fault alarm;

[0087] (3) Confirm that the frequency converter cabinet is in the closed state;

[0088] (4) Confirm the connection status of the field sensor;

[0089] (5) Determine the speed control mode and set the system parameters according to the test procedures;

[0090] (6) If the control mode is free control mode, set the acceleration and deceleration time, time, torque limit and speed parameters in the free control mode interface, confirm the system status and start the main motor;

[0091] (7) If the control mode is program control mode, set the parameters such as the number of cycles, target speed for each section, acceleration and deceleration time for each section, duration for each section, and torque limit for each section in the program control mode interface, confirm the system status and start the main motor;

[0092] (8) Start interlock protection functions, including gearbox temperature protection function, gearbox vibration protection function and power over-limit protection function;

[0093] (9) The variable frequency motor fan is in operation;

[0094] (10) The gearbox oil cooler is in operation;

[0095] (11) Start the automatic control program.

[0096] The present invention can continuously monitor the operating status of the test system, process parameters and test parameters of the floating ring product, and form records and alarm information, so that the entire test process is in a visualized, controllable and safe operating mode.

[0097] The present invention monitors and logically judges key parameters in the test system to avoid distracting the operator's attention, and realizes automatic control of the rotation speed through logical judgment, which reduces the operation time, improves the test efficiency, and enhances the automation level of the system.

[0098] The present invention can set up to seven sections of speed control programs, and adopts a step-by-step increasing method to control the speed to reach the rated value, thereby avoiding damage to the floating ring product and the test device due to complex working conditions during direct high-speed starting, and reducing the risk of test failure.

[0099] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. The PLC-based normal temperature floating ring seal test speed automatic control system is characterized by: Including upper configuration, PLC control subsystem, test data measurement subsystem, data transmission subsystem, speed regulation subsystem; Upper configuration: transmit the set operating parameters and target values ​​to the data transmission subsystem; Test data measurement subsystem: measure the speed value and power value during the test; send the speed value and power value to the data transmission subsystem; Data transmission subsystem: receives the operating parameters and target values ​​from the upper configuration, and sends the operating parameters and target values ​​to the PLC control subsystem; receives the speed value and power value from the test data measurement subsystem, and sends the speed value and power value to the PLC control subsystem; PLC control subsystem: receiving operating parameters, target values, speed values, and power values ​​from the data transmission subsystem; using the operating parameters, target values, speed values, and power values ​​as input values, inputting the preset PLC speed program, outputting speed control signals, and sending the speed control signals to the speed regulation subsystem; receiving operating status and current and voltage data from the speed regulation subsystem; judging whether there is a fault based on the operating status, and sending the operating status to the upper configuration display if there is no fault; generating alarm information and sending it to the upper configuration display if there is a fault; sending current and voltage data to the upper configuration display for monitoring; Speed ​​regulation subsystem: Receives the speed control signal from the PLC control subsystem, and adjusts the speed of the test device according to the speed control signal; monitors the current and voltage during the test, and sends the operating status and current and voltage to the PLC control subsystem.

2. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 1 is characterized by: The upper configuration display content includes the main screen, program control screen, flow control screen, parameter setting screen, alarm record, and flow chart.

3. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 2 is characterized by: The program control screen includes two speed control modes, namely free control mode and program control mode; wherein the free control mode is to control the speed manually; and the program control mode is to realize automatic adjustment of the speed in sections according to the set value.

4. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 1 is characterized by: The test data measurement subsystem includes data collector and field sensors; Among them, the data acquisition device connects to various sensors at the test site, collects real-time signals from the sensors, and records them; the field sensors include temperature transmitters, mass flow meters, pressure transmitters, speed measurement modules, power measurement modules, and vibration sensors; the field sensors use a two-wire signal transmission method, and each measurement channel is equipped with a signal isolator.

5. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 1 is characterized by: The data transmission subsystem adopts Ethernet mode to interconnect different subsystems with the test device; realizes sending the signals recorded by the data collector to the upper configuration; and realizes data transmission between the upper configuration and the PLC control subsystem through the OPC communication protocol.

6. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 5 is characterized by: The OPC communication protocol adopts dual network redundancy for data transmission to ensure the stability of data transmission.

7. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 1 is characterized by: The speed regulation subsystem includes: a frequency converter, a variable frequency motor, a filter, an output reactor and an encoder.

8. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 7 is characterized by: The PLC control subsystem obtains the gear box temperature signal, motor speed signal, and power signal respectively measured by the temperature transmitter, speed measurement module, and power measurement module, which are used for the control program of the speed of the test device; the PLC control subsystem obtains the pipeline flow and pressure signals respectively measured by the mass flow meter and pressure transmitter, which are used to control the opening of the pipeline valve; the PLC control subsystem controls the start and stop of the inverter in the speed adjustment subsystem and the change of the inverter control mode through buttons.

9. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 8 is characterized by: The PLC control subsystem realizes data communication with the frequency converter in the speed regulation subsystem via Ethernet.

10. The PLC-based normal temperature floating ring seal test speed automatic control system according to claim 3 is characterized by: The control process of the speed automatic control system is: S1. Confirm whether the system status is normal; the normal system status includes no fault alarm in each subsystem, normal connection and setting of the on-site sensor, and normal display of the upper configuration screen; otherwise, the system status is abnormal and the test is stopped; S2. Determine the speed control mode and set the system parameters according to the test conditions; S3. If the control mode is free control mode, set the acceleration and deceleration time, time, torque limit and speed in the free control mode interface, confirm the system status and start the main motor; S4. If the control mode is program control mode, set the number of cycles, target speed for each section, acceleration and deceleration time for each section, duration for each section, and torque limit for each section in the program control mode interface, confirm the system status and start the main motor; S5. Start the system interlock protection function; the interlock protection function includes gearbox temperature protection function, gearbox vibration protection function and power over-limit protection function; S6. Determine whether the auxiliary equipment of the motor and the gearbox of the test bench are in operation and start the test; the auxiliary equipment of the gearbox of the test bench includes the fan of the test bench and the oil cooler of the test bench.

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