Automatic loop control system based on PXI bus

Abstract

The invention provides an automatic loop control system based on a PXI (PCI eXtensions for Instrumentation) bus, relates to the technical field of reactor control, aims to optimize a control loop and improve the control precision of automatic temperature and pressure regulation, and comprises a high-speed data acquisition system and a measurement control system, the high-speed data acquisition system is connected with the measurement control system through a communication protocol; the high-speed data acquisition system is used for data acquisition; and the measurement control system is used for automatically adjusting and compensating the temperature and pressure of the reactor based on data acquired by the high-speed data acquisition system. The device has the advantages of being simple in structure and improving safety and reliability of a control loop.

Description

Technical Field

[0001] The present invention relates to the field of reactor control technology, in particular to a loop automatic control system based on a PXI bus. Background Art

[0002] Since the reactor primary loop system is in a high temperature and high pressure environment for a long time, the temperature and pressure fluctuations need to be monitored in real time.

[0003] If the operation is carried out manually, and the pump and valve equipment in the loop has a high frequency and repetition, it is easy to cause mental fatigue and incorrect response to parameter over-limit conditions, increasing the risk of safety accidents. If risk control is not carried out in time, energy loss will occur, reducing the working efficiency of the unit or equipment and increasing the cost budget. Therefore, automatic detection is usually used for temperature and pressure, and compensation control is performed through PID and other control methods. Although PXI bus detection technology has been widely used in parameter measurement in machinery, petroleum, and chemical related fields, most automatic control systems only automatically control a single system, parameter, and part of the production process, and still focus on data collection and then processing for system analysis, which has lag. At the same time, during the control process, the accuracy of the control method needs to be improved.

[0004] Therefore, there is an urgent need to design a control system for the reactor to optimize the control loop and improve the control accuracy of automatic temperature and pressure regulation. Summary of the invention

[0005] The object of the present invention is to provide a loop automatic control system based on PXI bus, which can optimize the control loop and improve the control accuracy of automatic regulation of temperature and pressure.

[0006] The embodiments of the present invention are implemented by the following technical solutions:

[0007] A loop automatic control system based on PXI bus, including a high-speed data acquisition system and a measurement control system;

[0008] The high-speed data acquisition system and the measurement control system are connected via a communication protocol;

[0009] The high-speed data acquisition system is used for data acquisition; the measurement control system is used for automatic regulation and compensation of reactor temperature and pressure based on the data acquired by the high-speed data acquisition system.

[0010] Preferably, the high-speed data acquisition system includes a PXI bus, a synchronous acquisition module and a remote controller;

[0011] The synchronous acquisition module is used to transmit the collected data to the PXI bus; the remote controller distributes and stores the data through the PXI bus and transmits the data to the digital I / O and transmits data to and from the host computer.

[0012] Preferably, the measurement and control system includes OPTO22 PAC, a data processing module and a data acquisition module;

[0013] The method of automatically adjusting and compensating the reactor temperature and pressure is established by the OPTO22 PAC; a simulation model is established in the host computer; the OPTO22 PAC and the host computer form a closed-loop negative feedback loop;

[0014] The synchronous acquisition module is connected to the OPTO22 PAC via optical fiber, and dual-machine communication is performed via TCP protocol.

[0015] Preferably, the two-machine communication method comprises the following steps:

[0016] The OPTO22 PAC sends a session request via a set data terminal with a synchronization flag;

[0017] The synchronous acquisition module replies by sending back a data segment with various items, including a synchronization flag set, a sequence number of the starting byte of the data segment to be sent, and an acknowledgement with a byte sequence number of the next data segment to be received;

[0018] The synchronous acquisition module requests the OPT022 PAC to send back another data segment with a confirmation sequence number and a confirmation number.

[0019] Preferably, the method for automatic regulation and compensation of reactor temperature and pressure comprises the following steps:

[0020] Build simulation models;

[0021] Collect temperature and pressure data in real time;

[0022] Temperature compensation and pressure compensation are performed based on the simulation model, the temperature data and the pressure data.

[0023] Preferably, the simulation model is established to map the relationship between the reaction time and the standard temperature and the relationship between the reaction time and the standard pressure.

[0024] Preferably, the method for performing temperature compensation is:

[0025] Get the temperature data T at the current time t real (t) and the standard temperature T st The difference δ of (t) T (t):

[0026] δ T (t) = T st (t)-T real (t);

[0027] Obtain the temperature data T before the temperature compensation at N moments up to the current moment t real (ti) and the standard temperature T st The difference δ of (ti) T (ti):

[0028] δ T (ti) = T st (ti)-T real (ti), i = 1, 2, ..., N;

[0029] Get the PID temperature compensation parameter e at the current time t T (t):

[0030] e T (t) = δ T (t)×(2-e -parT(t) )×KT c ;

[0031]

[0032] Based on the temperature PID compensation parameter e T (t) Perform PID control:

[0033]

[0034] Among them, e is a natural constant, KT c KT is the temperature compensation parameter adjustment coefficient, p , KT i and KT d They are temperature proportional gain, temperature integral gain and temperature differential gain respectively, and T(t) is the output of temperature control at time t.

[0035] Preferably, the method for performing pressure compensation is:

[0036] Get the pressure data P at the current time t real (t) and the standard pressure P st The difference δ of (t) P (t):

[0037] δ P (t) = P st (t)-P real (t);

[0038] Obtain the temperature data P before the temperature compensation at N moments up to the current moment t real (ti) and the standard temperature P st The difference δ of (ti) P (ti):

[0039] δ P (ti) = P st (ti)-P real (ti), i = 1, 2, ..., N;

[0040] Get the PID pressure compensation parameter e at the current time t P (t):

[0041] e P (t) = δ P (t)×(2-e -parP (t))×KP c ;

[0042]

[0043] Based on the pressure PID compensation parameter e T (t) Perform PID control:

[0044]

[0045] Among them, e is a natural constant, KP c is the pressure compensation parameter adjustment coefficient, KP p , KP i and KP d They are pressure proportional gain, pressure integral gain and pressure differential gain respectively, and P(t) is the output of pressure control at time t.

[0046] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0047] The present invention combines a high-speed data acquisition system and a measurement control system to design a control system, and realizes efficient and low-latency data interaction between the two systems, thereby improving the efficiency and reliability of automatic control;

[0048] The protocol mode between the systems of the present invention helps to reduce information transmission errors and further enhance the speed and stability of information transmission;

[0049] The present invention optimizes the data required for PID, flexibly adjusts parameters during the control process to further optimize the data, and improves the accuracy of temperature and pressure compensation;

[0050] The present invention is reasonably designed and does not require overly complex structural design or overly complex communication strategy design for the system. At the same time, the optimization calculation amount of the control algorithm is also small, and it has a high cost-effectiveness and is easy to promote and implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of the structure of a PXI bus-based loop automatic control system provided in Example 1 of the present invention;

[0052] Figure 2 A flowchart of a case of a communication connection between two systems based on the TCP / IP protocol;

[0053] Figure 3 The figure is a flowchart of a case of data transmission between two systems based on TCP / IP protocol. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] Example 1

[0056] This embodiment provides a loop automatic control system based on PXI bus. Figure 1 , including high-speed data acquisition system and measurement control system;

[0057] The high-speed data acquisition system and the measurement control system are connected via a communication protocol;

[0058] The high-speed data acquisition system is used for data acquisition; the measurement control system is used for automatic regulation and compensation of reactor temperature and pressure based on the data acquired by the high-speed data acquisition system.

[0059] In this embodiment, the high-speed data acquisition system includes a PXI bus, a synchronous acquisition module and a remote controller; specifically, the PXI bus can use a NIPXI 1088 9-slot chassis, and the PXI bus can organically connect the computer with each board and perform data interaction and transmission between them;

[0060] The synchronous acquisition module is used to transfer the collected data to the PXI bus; the remote controller allocates and stores the data through the PXI bus and transfers the data to the digital I / O and transmits data to the host computer. The host computer can serve as the overall scheduling, calculation, and processing unit of the entire high-speed data acquisition, responsible for data recording, processing, and storage.

[0061] On the other hand, the measurement control system includes an OPTO22 PAC, a data processing module and a data acquisition module;

[0062] The method of automatically adjusting and compensating the reactor temperature and pressure is established by the OPTO22 PAC; a simulation model is established in the host computer; the OPTO22 PAC and the host computer form a closed-loop negative feedback loop;

[0063] The synchronous acquisition module is connected to the OPTO22 PAC via optical fiber, and dual-machine communication is performed via TCP protocol.

[0064] Furthermore, the synchronous acquisition module can adopt NIPXI e 6358 16 channels, which can collect signals such as current voltage, temperature, pressure, power, and differential pressure signals. The purpose of the dual-machine communication method is to achieve the synchronization of sending and receiving OPTO22 and NI data segments, determine the acceptable number between the two machines, and establish a virtual connection, which specifically includes the following steps:

[0065] The OPTO22 PAC sends a session request through a set data terminal with a synchronization flag; first specify the network port, and use the listening TCP node to establish a TCP listener, first check whether there is a new client connection, if so, wait for the host's connection request, this is the initialization process, four TCP data nodes are written in the program flowchart to send data, respectively, data storage path, data name, acquisition frequency, acquisition points, this sending method is conducive to the client receiving data;

[0066] The synchronous acquisition module replies by sending back a data segment with multiple items, including the synchronization flag setting, the sequence number of the starting byte of the data segment to be sent, and the response with the byte sequence number of the next data segment to be received; similarly, the client also uses four array data sent by the TCP data node server to read the setting location first, and then read the length to find the accurate data;

[0067] The synchronous acquisition module requests the OPTO22 PAC to send back another data segment with a confirmation sequence number and a confirmation number.

[0068] During the specific implementation, the hardware set up includes computers, analog and digital acquisition cards, controllers, power supplies, CAN cards, etc.; the software is programmed using the OPTO22 PAC Control framework language, and the user interface is developed using PAC Display and labview. Appropriate control algorithms and communication protocols can be used to achieve loop automatic control.

[0069] Figure 2-Figure 3 The schematic diagram of the case of the communication connection and data transmission process of the dual-system interaction based on the TCP / IP protocol is provided. In the figure, T represents the judgment result of yes, F represents no, and in this case, the client is OPTO22 PAC and the server is a synchronous acquisition module. When the communication connection is made, first open the external communication, then confirm that the communication program is started, judge whether the communication has started, if not, return to open the external communication, if it has started, judge whether it is initialized, if not, send a string, if initialized, reset the initialization value to zero and then return to open the external communication; when transmitting data, after the connection is established, the server generates waveform data, and then starts to read and write data with the client to transmit data. After the transmission is completed, the client displays the waveform, and the above operations are continued before exiting the data transmission cycle.

[0070] Example 2

[0071] This embodiment is based on the technical solution of Embodiment 1, and mainly further illustrates the method for automatic adjustment and compensation of reactor temperature and pressure.

[0072] As a preferred solution of this embodiment, the method for automatic regulation and compensation of reactor temperature and pressure comprises the following steps:

[0073] Build simulation models;

[0074] Collect temperature and pressure data in real time;

[0075] Temperature compensation and pressure compensation are performed based on the simulation model, the temperature data and the pressure data.

[0076] In this embodiment, the simulation model is established to map the relationship between the reaction time and the standard temperature and the relationship between the reaction time and the standard pressure.

[0077] Preferably, the method for performing temperature compensation is:

[0078] Get the temperature data T at the current time t real (t) and the standard temperature T st The difference δ of (t) T (t):

[0079] δ T (t) = Tst (t)-T real (t);

[0080] Obtain the temperature data T before the temperature compensation at N moments up to the current moment t real (ti) and the standard temperature T st The difference δ of (ti) T (ti):

[0081] δ T (ti) = T st (ti)-T real (ti), i = 1, 2, ..., N;

[0082] Get the PID temperature compensation parameter e at the current time t T (t):

[0083] e T (t) = δ T (t)×(2-e -parT (t))×KT c ;

[0084]

[0085] Based on the temperature PID compensation parameter e T (t) Perform PID control:

[0086]

[0087] Among them, e is a natural constant, KT c KT is the temperature compensation parameter adjustment coefficient, p , KT i and KT d They are temperature proportional gain, temperature integral gain and temperature differential gain respectively, and T(t) is the output of temperature control at time t.

[0088] In addition, the method for performing pressure compensation is:

[0089] Get the pressure data P at the current time t real (t) and the standard pressure P st The difference δ of (t) P (t):

[0090] δ P (t) = P st (t)-P real (t);

[0091] Obtain the temperature data P before the temperature compensation at N moments up to the current moment t real(ti) and the standard temperature P st The difference δ of (ti) P (ti):

[0092] δ P (ti) = P st (ti)-P real (ti), i = 1, 2, ..., N;

[0093] Get the PID pressure compensation parameter e at the current time t P (t):

[0094] e P (t) = δ P (t)×(2-e -parP(t) )×KP c ;

[0095]

[0096] Based on the pressure PID compensation parameter e T (t) Perform PID control:

[0097]

[0098] Among them, e is a natural constant, KP c is the pressure compensation parameter adjustment coefficient, KP p , KP i and KP d They are pressure proportional gain, pressure integral gain and pressure differential gain respectively, and P(t) is the output of pressure control at time t.

[0099] It is particularly noted that the KT involved in this embodiment c , KT p , KT i and KT d KP c , KP p , KP i and KP d All of them can be determined by experience, that is, in the same control scheme, only one parameter is adjusted and other parameter values ​​are fixed to find the optimal value of this parameter. This embodiment dynamically adjusts the actual deviation data in the PID control based on the floating situation of the deviation over a period of time, thereby adjusting the adjustment range of the temperature and pressure output based on the deviation burden situation, and further improving the accuracy of the compensation control.

[0100] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A loop automatic control system based on PXI bus, characterized in that: Including high-speed data acquisition system and measurement control system; The high-speed data acquisition system and the measurement control system are connected via a communication protocol; The high-speed data acquisition system is used for data acquisition; the measurement control system is used for automatic regulation and compensation of reactor temperature and pressure based on the data acquired by the high-speed data acquisition system.

2. A loop automatic control system based on PXI bus according to claim 1, characterized in that: The high-speed data acquisition system includes a PXI bus, a synchronous acquisition module and a remote controller; The synchronous acquisition module is used to transmit the collected data to the PXI bus; the remote controller distributes and stores the data through the PXI bus and transmits the data to the digital I / O and transmits data to and from the host computer.

3. A loop automatic control system based on PXI bus according to claim 2, characterized in that: The measurement and control system includes OPTO22 PAC, data processing module and data acquisition module; The method of automatically adjusting and compensating the reactor temperature and pressure is established by the OPTO22 PAC; a simulation model is established in the host computer; the OPTO22 PAC and the host computer form a closed-loop negative feedback loop; The synchronous acquisition module is connected to the OPTO22 PAC via optical fiber, and dual-machine communication is performed via TCP protocol.

4. A loop automatic control system based on PXI bus according to claim 3, characterized in that: The two-machine communication method comprises the following steps: The OPTO22 PAC sends a session request via a set data terminal with a synchronization flag; The synchronous acquisition module replies by sending back a data segment with various items, including a synchronization flag set, a sequence number of the starting byte of the data segment to be sent, and an acknowledgement with a byte sequence number of the next data segment to be received; The synchronous acquisition module requests the OPTO22 PAC to send back another data segment with a confirmation sequence number and a confirmation number.

5. The loop automatic control system based on PXI bus according to claim 1, characterized in that: The method for automatic regulation and compensation of reactor temperature and pressure comprises the following steps: Build simulation models; Collect temperature and pressure data in real time; Temperature compensation and pressure compensation are performed based on the simulation model, the temperature data and the pressure data.

6. A loop automatic control system based on PXI bus according to claim 5, characterized in that: The simulation model is used to map the relationship between the reaction time and the standard temperature and the relationship between the reaction time and the standard pressure.

7. A loop automatic control system based on PXI bus according to claim 6, characterized in that: The method for temperature compensation is: Get the temperature data T at the current time t real (t) and the standard temperature T st The difference δ of (t) T (t): δ T (t)=T st (t)-T real (t); Obtain the temperature data T before the temperature compensation at N moments up to the current moment t real (ti) and the standard temperature T st The difference δ of (ti) T (ti): δ T (t-i)=T st (t-i)T real (t-i),i=1,2,...,N; Get the PID temperature compensation parameter e at the current time t T (t): e T (t)=δ T (t)×(2-e -parT(t) )×KT c ; Based on the temperature PID compensation parameter e T (t) Perform PID control: Among them, e is a natural constant, KT c KT is the temperature compensation parameter adjustment coefficient, p , KT i and KT d They are temperature proportional gain, temperature integral gain and temperature differential gain respectively, and T(t) is the output of temperature control at time t.

8. A loop automatic control system based on PXI bus according to claim 7, characterized in that: The method for pressure compensation is: Get the pressure data P at the current time t real (t) and the standard pressure P st The difference δ of (t) P (t): δ P (t)=P st (t)-P real (t); Obtain the temperature data P before the temperature compensation at N moments up to the current moment t real (ti) and the standard temperature P st The difference δ of (ti) P (ti): δ P (t-i)=P st (t-i)-P real (t-i),i=1,2,…,N; Get the PID pressure compensation parameter e at the current time t P (t): e P (t)=δ P (t)×(2-e -parP(t) ×KP c ; Based on the pressure PID compensation parameter e T (t) Perform PID control: Among them, e is a natural constant, KP c KP is the pressure compensation parameter adjustment coefficient, p , kP i and kP d They are pressure proportional gain, pressure integral gain and pressure differential gain respectively, and P(t) is the output of pressure control at time t.

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