PLC-based pit furnace flow monitoring system and control method

Abstract

The invention provides a PLC-based pit furnace flow monitoring system and control method, and belongs to the technical field of heat treatment equipment automation control, and the system comprises a first data acquisition module which is used for carrying out data acquisition based on a first sensor group arranged at a target inlet and a target outlet of a pit furnace; the second data acquisition module is used for performing data acquisition based on a second sensor group arranged at a target auxiliary point of the pit furnace, and the PLC analysis module is used for preprocessing and comprehensively analyzing an acquisition result, determining to-be-adjusted valves and controlling each to-be-adjusted valve based on a PID control algorithm; the safety protection module is used for performing comparative analysis with corresponding alarm constraints, realizing alarm reminding, performing forward elimination on the alarm reminding according to a control result, and feeding back the control result to the PLC analysis module to judge whether the to-be-adjusted valve needs to be continuously controlled or not; and the visualization module is used for displaying the acquisition result, the control result and the reminding result in real time. And continuous and accurate control is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control of heat treatment equipment, and particularly to a pit furnace flow monitoring system and control method based on PLC. Background Art

[0002] The flow control of traditional pit furnaces mostly relies on manual adjustment or simple mechanical valves, which has problems such as slow response speed, low precision, and inability to adjust in real time. For example, the steam flow control of a steam treatment pit furnace relies on manual observation of the sedimentation hopper status, which easily leads to high energy consumption and poor process stability. In the prior art, although there are flow monitoring systems based on PLC (such as industrial pipeline flow control), the data involved is relatively single and generally only adjusts by comparing a single numerical value of the flow rate. The adjustment method is relatively rough. If this method continues to be used to adjust the pit furnace, due to the special structure of the pit furnace (such as high-temperature sealing and medium diversity), the adaptability is insufficient, and thus there is a lack of an optimization scheme for multi-parameter coordinated control in the furnace.

[0003] Therefore, the present invention proposes a pit furnace flow monitoring system and control method based on PLC. Summary of the Invention

[0004] The present invention provides a pit furnace flow monitoring system and control method based on PLC, which is used to collect flow rate, temperature, and pressure by setting a sensor group, avoid control errors caused by overly single data, improve the actual reliability of flow rate acquisition, and then determine the valve to be adjusted through analysis and processing of the data set to achieve precise control. Furthermore, through comparative analysis, positive elimination, and visual display, continuous precise control is facilitated and it is convenient for personnel to view.

[0005] The present invention provides a pit furnace flow monitoring system based on PLC, including:

[0006] A first data acquisition module, configured to collect data of the pit furnace based on a first sensor group arranged at the target inlet and target outlet of the pit furnace to obtain a first data set, wherein the first sensor group is related to a flow sensor;

[0007] A second data acquisition module, configured to collect data based on a second sensor group arranged at the target auxiliary point of the pit furnace to obtain a second data set, wherein the second sensor group is related to a pressure sensor and a temperature sensor, and the acquisition time of the second data set is consistent with that of the first data set;

[0008] A PLC analysis module, configured to preprocess and comprehensively analyze the first data set and the second data set, determine the valve to be adjusted, and then control each valve to be adjusted based on the PID control algorithm;

[0009] A safety protection module, which is used to compare and analyze with corresponding alarm constraints during the preprocessing of the first data set and the second data set to achieve alarm reminders. At the same time, the alarm reminders are positively eliminated according to the control results, and the positive elimination results are fed back to the PLC analysis module to determine whether the regulating valve to be treated needs to be continuously controlled;

[0010] A visualization module, which is used to display in real time the acquisition results of the data acquisition module, the control results of the PLC analysis module, and the alarm reminder results of the safety protection module.

[0011] Preferably, the first data acquisition module includes:

[0012] A first construction unit, which is used to construct a first array based on the data acquisition results of the first sensor group set at the target inlet;

[0013] A second construction unit, which is used to construct a second array based on the data acquisition results of the second sensor group set at the target outlet;

[0014] An alignment processing unit, which is used to align the first array and the second array according to the flow delay time from the target inlet to the target outlet of the pit furnace to obtain an array matrix;

[0015] An attribute analysis unit, which is used to analyze the first data attribute of the first flow pair and the second data attribute of the second flow pair in each column vector of the array matrix, where the data attributes are missing attributes and correct attributes;

[0016] A replacement unit, which is used to perform discrete analysis on each row vector of the array matrix to lock discrete points, and perform replacement according to the first distribution of the discrete points existing in the first flow pair and the second distribution of the discrete points existing in the second flow pair, and in combination with the first data attribute and the second data attribute;

[0017] A first set determination unit, which is used to obtain a new matrix according to the replacement result, and regard all the data in the new matrix as the first data set;

[0018] Wherein, a first sensor group is respectively arranged at the target inlet and the target outlet, and the first sensor group includes 2 flow sensors, and the 2 flow sensors are arranged front and back, and the distance between the first flow sensor and the second flow sensor is 3 cm.

[0019] Preferably, the attribute analysis unit includes:

[0020] A reference acquisition subunit, which is used to obtain the current opening degree of the target valve associated with the target inlet at the acquisition moment of each first flow pair, and combine the preset input flow rate to obtain a first reference flow rate;

[0021] A calculation subunit, configured to calculate a first difference between the first flow rate and the second flow rate in the corresponding first flow rate pair and the first reference flow rate respectively, and a second difference. If the first difference and the second difference respectively satisfy the corresponding preset difference constraints, at this time, it is determined that the first data attribute of the corresponding first flow rate pair is the correct attribute;

[0022] Otherwise, it is determined that the first data attribute of the corresponding first flow rate pair is the missing attribute.

[0023] Preferably, the replacement subunit includes:

[0024] A combination determination subunit, configured to determine the attribute combination of each column vector in the array matrix;

[0025] If the attribute combination is two correct attributes, at this time, the corresponding column vector remains unchanged;

[0026] A first analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are no discrete points in the flow rate pair corresponding to the missing attribute, at this time, screen the correct attribute closest to the corresponding missing attribute. If both flow rate pairs in the column vector corresponding to the closest correct attribute are correct attributes, at this time, replace the flow rate whose difference in the flow rate pair corresponding to the missing attribute does not satisfy the corresponding preset difference constraint according to the first average value of the flow rate pair corresponding to the closest correct attribute;

[0027] A second analysis subunit, configured to, if the other flow rate pair in the column vector corresponding to the closest correct attribute is a missing attribute, at this time, obtain the correct attribute closest to the missing attribute of the other flow rate pair, and obtain the second average value of the required flow rate pairs involved in the column corresponding to the correct attribute closest to the missing attribute of the other flow rate pair;

[0028] Perform an averaging process on the first average value and the second average value to obtain a third average value, and replace the flow rate whose difference in the flow rate pair corresponding to the missing attribute does not satisfy the corresponding preset difference constraint;

[0029] A third analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are two discrete points with the same discrete direction in the flow rate pair corresponding to the missing attribute, at this time, keep the two discrete points unchanged;

[0030] A fourth analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are two discrete points with inconsistent discrete directions or one discrete point in the flow rate pair corresponding to the missing attribute, at this time, lock the row vector corresponding to the flow rate pair of the missing attribute and continuously screen N0 flows based on the corresponding discrete points in the locked row vector to obtain the corresponding variance, and then replace the flow rate of the corresponding discrete point;

[0031] The fifth analysis subunit is configured to, when all the attribute combinations are missing attributes, eliminate the corresponding column vectors at this time.

[0032] Preferably, the fourth analysis subunit includes:

[0033] A coefficient determination block for determining the value coefficient of the corresponding row vector according to the distribution of discrete points in each row vector of the flow pair corresponding to the missing attribute;

[0034] ;

[0035] ;

[0036] ;

[0037] wherein, represents the value coefficient of the corresponding row vector; represents the number of discrete points in the corresponding row vector; represents when the value function of the corresponding row vector; represents the number of vector intercept segments of adjacent discrete points existing in the corresponding row vector; represents the average value of all remaining flows except two discrete points in the i1-th vector intercept segment; represents the average value of the flows of two discrete points in the i1-th vector intercept segment; represents the judgment function of the i1-th vector intercept segment; respectively represent the flow of the first discrete point and the flow of the second discrete point in the i1-th vector intercept segment; max represents the maximum symbol; represents the variance of all flows involved in the i1-th vector intercept segment; represents the average value of all remaining points except discrete points in the corresponding row vector;

[0038] A replacement block for replacing the flow of the corresponding discrete point according to the variance of the corresponding row vector, the value coefficient of the corresponding row vector, and in combination with the flow L0 of the non-discrete point closest to the corresponding discrete point, according to where, represents the flow of the corresponding discrete point; represents the variance obtained by continuously screening N0 flows based on the corresponding discrete point.

[0039] Preferably, the PLC analysis module includes:

[0040] A data extraction unit for extracting the same group of data at the same aligned time point from the first data set and the second data set, where the same group of data includes: two flow rates at the target inlet, two flow rates at the target outlet, and the temperature and pressure at each target auxiliary point;

[0041] A model analysis unit for inputting the temperature, pressure, and two flow rates at the target outlet in the same group of data into a loss analysis model to obtain a theoretical loss;

[0042] A label assignment unit for, if the first difference between the average values of the two flow rates at the target inlet and the average values of the two at the target outlet is less than or equal to the sum of the theoretical loss and the normal usage flow rate of the corresponding process stage, assigning a first adjustment label to the control valve at the target outlet at the corresponding aligned time point;

[0043] Otherwise, assigning a second adjustment label to the control valve at the target inlet at the corresponding aligned time point;

[0044] A PID adjustment unit for determining the control valve to be adjusted and the adjustment opening degree of the control valve to be adjusted based on the PID control algorithm according to the adjustment labels obtained in sequence and the second difference between the first difference and the sum corresponding to each label, so as to achieve adjustment.

[0045] Preferably, the safety protection module includes:

[0046] An alarm unit for obtaining an alarm message by matching the second difference with a difference - comparison table and giving an alarm reminder;

[0047] A continue control unit for adjusting each second difference according to the control result. If more than half of the adjusted second differences are still greater than 0, at this time, it is determined based on the PLC analysis module that the control valve to be adjusted needs to be continuously controlled.

[0048] The present invention provides a control method for a well - type furnace flow monitoring system based on a PLC, including:

[0049] Step 1: Data collection is performed on the well - type furnace based on a first sensor group arranged at the target inlet and the target outlet of the well - type furnace to obtain a first data set, where the first sensor group is related to flow sensors;

[0050] Step 2: Data collection is performed based on a second sensor group arranged at the target auxiliary points of the well - type furnace to obtain a second data set, where the second sensor group is related to pressure sensors and temperature sensors, and the acquisition time of the second data set is consistent with that of the first data set;

[0051] Step 3: Preprocess and comprehensively analyze the first data set and the second data set to determine the valves to be adjusted, and then control each valve to be adjusted based on the PID control algorithm;

[0052] Step 4: During the preprocessing of the first data set and the second data set, conduct a comparative analysis with the corresponding alarm constraints to achieve alarm reminders. At the same time, positively eliminate the alarm reminders according to the control results, and determine whether it is necessary to continue controlling the valves to be adjusted;

[0053] Step 5: Real-time display the acquisition results, control results, and alarm reminder results.

[0054] Compared with the prior art, the beneficial effects of the present application are as follows: By setting up a sensor group to collect flow rate, temperature, and pressure, it avoids control errors caused by overly single data, improves the actual reliability of flow rate acquisition, and then determines the valves to be adjusted through analysis and processing of the data set to achieve precise control. Furthermore, through comparative analysis, positive elimination, and visual display, it facilitates continuous precise control and is convenient for personnel to view.

[0055] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written specification and the accompanying drawings.

[0056] The following further describes the technical solutions of the present invention in detail through the accompanying drawings and embodiments. Description of the Drawings

[0057] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0058] Figure 1 It is a module structure diagram of a well-type furnace flow monitoring system based on PLC in an embodiment of the present invention;

[0059] Figure 2 It is a flowchart of a control method for a well-type furnace flow monitoring system based on PLC in an embodiment of the present invention;

[0060] Figure 3 It is a connection structure diagram of a well-type furnace flow monitoring system based on PLC in an embodiment of the present invention. Detailed Embodiments

[0061] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0062] The present invention provides a well - type furnace flow monitoring system based on a PLC, as Figure 1 shown, including:

[0063] A first data acquisition module, which is used to collect data from the well - type furnace based on a first sensor group arranged at the target inlet and target outlet of the well - type furnace, and obtain a first data set. Among them, the first sensor group is related to a flow sensor;

[0064] A second data acquisition module, which is used to collect data based on a second sensor group arranged at the target auxiliary point of the well - type furnace, and obtain a second data set. Among them, the second sensor group is related to a pressure sensor and a temperature sensor, and the acquisition time of the second data set is the same as that corresponding to the first data set;

[0065] A PLC analysis module, which is used to pre - process and comprehensively analyze the first data set and the second data set, determine the regulating valves to be adjusted, and then control each regulating valve to be adjusted based on the PID control algorithm;

[0066] A safety protection module, which is used to compare and analyze with the corresponding alarm constraints during the pre - processing of the first data set and the second data set to realize alarm reminder. At the same time, the alarm reminder is positively eliminated according to the control result, and the positive elimination result is fed back to the PLC analysis module to judge whether it is necessary to continue controlling the regulating valves to be adjusted;

[0067] A visualization module, which is used to display the acquisition results of the data acquisition module, the control results of the PLC analysis module, and the alarm reminder results of the safety protection module in real - time.

[0068] In this embodiment, the flow sensing unit: includes an electromagnetic flowmeter, a vortex - street flowmeter, etc., which are installed on the medium input / output pipelines of the well - type furnace to collect flow data in real - time. The target inlet is the medium input port, the target outlet is the medium output port, and in this application, the first sensor group can be replaced to measure the flow of gas or liquid.

[0069] In this embodiment, the PLC control unit adopted by the PLC analysis module is specifically the Siemens S7 - 1200 series PLC, which receives sensor signals and executes the PID control algorithm to adjust the opening of the proportional valve.

[0070] In this embodiment, the visualization module designs a monitoring interface through the PROFACE configuration software to display the flow curve, alarm status, and historical data, and supports remote parameter setting, etc.

[0071] In this embodiment, the data transmission between modules supports Modbus and Profibus protocols, realizing wireless / wired data transmission between PLC and host computer or mobile terminal.

[0072] In this embodiment, the fuzzy PID algorithm is combined to dynamically adjust the flow setting value according to the temperature and pressure in the furnace to avoid overshoot or oscillation.

[0073] In this embodiment, when the flow rate exceeds the limit, an audible and visual alarm is triggered, and the medium supply valve is closed in conjunction to prevent damage to the equipment.

[0074] In this embodiment, a steam treatment pit furnace is taken as an example:

[0075] Two vortex flowmeters are installed at the steam pipe inlet and outlet respectively, and the distance between the flowmeters installed at the inlet or outlet is 3 cm. This is mainly to reliably monitor the flow rate and avoid measurement errors caused by abnormalities in the flowmeter, which in turn lead to control errors.

[0076] A second sensor group is arranged on the top of the furnace cavity, and the second sensor group includes a temperature sensor and a pressure sensor, which may be a capacitive pressure sensor or an infrared temperature sensor.

[0077] The PLC compares the preset steam flow target value with the real-time data, and outputs a control signal to the electric regulating valve through PID calculation.

[0078] In this embodiment, the first data set includes the result of replacing the flow rates of the target inlet and the target outlet measured by the first sensor group at different times.

[0079] The second data set includes temperature and pressure measured by the second sensor group at different times.

[0080] In this embodiment, the target auxiliary point may be any point on the top of the furnace cavity.

[0081] In this embodiment, the unified data collection time of the target inlet, target outlet, and target auxiliary point is from moment t1 to moment t7. However, the flow result of the target outlet will be prior to or later than the flow result of the target inlet. Assuming that the delay is 1 moment, the collection time is regarded as from moment t2 to moment t7. This is because, during the operation of the pit furnace, there will be a certain buffer time from the entry of gas to the outlet, which is regarded as a delay, that is, the time is aligned from moment t2 to moment t7.

[0082] In this embodiment, the pre-processing and comprehensive analysis is to determine whether the air flow rate can make the fuel burn fully, or whether the heat in the furnace is reasonable, etc., based on the flow rate as a basis for judgment.

[0083] In this embodiment, there is a proportional valve for gas regulation in the pit furnace. For example, there is one for gas entering the furnace and one for gas discharging. Among them, the valve to be adjusted can be one of these proportional valves or both of them.

[0084] In this embodiment, positive elimination is to eliminate the existing flow difference towards a smaller value based on the control result.

[0085] In this embodiment, the alarm constraint is preset. It can be a constraint for the flow difference. For example, if the actual flow difference between the inlet and the outlet is within the set difference range, there is no need to alarm; otherwise, an alarm is required. At this time, the actual flow difference needs to be within the set difference range, which is the alarm constraint.

[0086] For example, if the actual flow difference is a1, the set difference range is (c1, c2), and a1 is within this range, it is determined that there is no need to alarm.

[0087] As Figure 3 shown, it is the connection structure diagram of the pit furnace flow monitoring system based on PLC.

[0088] The beneficial effects of the above technical solution are as follows: By setting up a sensor group to collect flow rate, temperature, and pressure, it avoids control errors caused by overly single data, improves the actual reliability of flow rate acquisition, and then determines the valve to be adjusted through analysis and processing of the data set to achieve precise control. Furthermore, through comparative analysis, positive elimination, and visual display, it facilitates continuous precise control and is convenient for personnel to view.

[0089] The present invention provides a pit furnace flow monitoring system based on PLC. The first data acquisition module includes:

[0090] A first construction unit for constructing a first array based on the data acquisition result of the first sensor group set at the target inlet;

[0091] A second construction unit for constructing a second array based on the data acquisition result of the second sensor group set at the target outlet;

[0092] An alignment processing unit for aligning the first array and the second array according to the flow delay time from the target inlet to the target outlet of the pit furnace to obtain an array matrix;

[0093] An attribute analysis unit for analyzing the first data attribute of the first flow pair and the second data attribute of the second flow pair in each column vector of the array matrix, where the data attribute is a missing attribute and a correct attribute;

[0094] A replacement unit for performing discrete analysis on each row vector in the array matrix to lock discrete points, and performing replacement according to the first distribution of discrete points existing in the first flow pair and the second distribution of discrete points existing in the second flow pair, and combining the first data attribute and the second data attribute;

[0095] A first set determination unit for obtaining a new matrix according to the replacement result and regarding all data in the new matrix as a first data set;

[0096] Wherein, a first sensor group is respectively arranged at the target inlet and the target outlet, and the first sensor group includes 2 flow sensors, and the 2 flow sensors are arranged front and back, and the distance between the first flow sensor and the second flow sensor is 3 cm.

[0097] In this embodiment, the first array is composed of the flow data collected by the two sensors at the inlet at each moment, and the second array is composed of the flow data collected by the two sensors at the outlet at each moment.

[0098] The flow delay time is the buffer time from when the gas starts to enter at the inlet to when it exists at the outlet, and is determined according to the process of the pit furnace itself. For example, it is 0.3 s, that is, from time t2 to time t7 is the aligned time.

[0099] ;

[0100] In this embodiment, the flow pair is two elements of two row vectors for the inlet or two row vectors for the outlet in the data matrix at a certain moment. For example, the column vector at time t2 is: , at this time, the inlet flow 1 and the inlet flow 2 are the first flow pair, and the outlet flow 3 and the outlet flow 4 are the second flow pair.

[0101] In this embodiment, the interquartile range (IQR) method is used to perform discrete analysis on the flow in the row vector to determine discrete points.

[0102] The beneficial effects of the above technical solution are: based on the first sensor group, the corresponding flow rates at the inlet and the outlet are respectively collected, and through alignment processing, it is convenient to reasonably judge the data attributes and subsequent discrete analysis and discrete point replacement, ensuring the reliability of the data set and improving the accuracy of subsequent proportional valve control.

[0103] The present invention provides a pit furnace flow monitoring system based on a PLC, and the attribute analysis unit includes:

[0104] A reference acquisition subunit for acquiring the current opening degree of the target valve associated with the target inlet at the acquisition moment of each first flow pair, and combining the preset input flow rate to obtain a first reference flow rate;

[0105] A calculation subunit, configured to calculate a first difference and a second difference between a first flow rate and a second flow rate in a corresponding first flow rate pair and a first reference flow rate respectively. If the first difference and the second difference respectively meet corresponding preset difference constraints, at this time, it is determined that the first data attribute of the corresponding first flow rate pair is the correct attribute;

[0106] Otherwise, it is determined that the first data attribute of the corresponding first flow rate pair is a missing attribute.

[0107] In this embodiment, the first reference flow rate = the current opening degree × the first flow rate.

[0108] In this embodiment, the first difference = the first flow rate - the first reference flow rate.

[0109] In this embodiment, the second difference = the second flow rate - the first reference flow rate.

[0110] The constraint for the corresponding preset difference is: whether the first difference and the second difference are within the range of (u1, u2), and the value of u1 is -0.3 cubic meters per hour, and the value of u2 is -3 cubic meters per hour.

[0111] In this embodiment, the judgment process for the second data attribute of the second flow rate pair is the same as that for the first data attribute of the first flow rate pair, and will not be elaborated here.

[0112] The beneficial effect of the above technical solution is: comparing the two flow rates in the flow rate pair with the reference flow rate respectively to set the attribute, which provides convenience for subsequent replacement.

[0113] The present invention provides a well-type furnace flow rate monitoring system based on a PLC. The replacement unit includes:

[0114] A combined determination subunit, configured to determine the attribute combination of each column vector in the array matrix;

[0115] If the attribute combination is two correct attributes, at this time, the corresponding column vector remains unchanged;

[0116] A first analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are no discrete points in the flow rate pair corresponding to the missing attribute, at this time, screen the correct attribute closest to the corresponding missing attribute. If both flow rate pairs in the column vector corresponding to the closest correct attribute are correct attributes, at this time, replace the flow rate that does not meet the corresponding preset difference constraint in the flow rate pair corresponding to the missing attribute according to the first average value of the flow rate pair corresponding to the closest correct attribute;

[0117] A second analysis subunit, configured to, if another traffic pair in the column vector corresponding to the nearest correct attribute is a missing attribute, at this time, obtain the correct attribute closest to the missing attribute of the other traffic pair, and obtain the second average value of the required traffic pairs involved in the column corresponding to the correct attribute closest to the missing attribute of the other traffic pair;

[0118] Perform an averaging process on the first average value and the second average value to obtain a third average value, so as to replace the traffic with a difference that does not meet the corresponding preset difference constraint in the traffic pair of the corresponding missing attribute;

[0119] A third analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are two discrete points with the same discrete direction in the traffic pair corresponding to the missing attribute, at this time, keep the two discrete points unchanged;

[0120] A fourth analysis subunit, configured to, if the attribute combination is one correct attribute and one missing attribute, and there are two discrete points with inconsistent discrete directions or there is one discrete point in the traffic pair corresponding to the missing attribute, at this time, lock the row vector corresponding to the traffic pair of the missing attribute and continuously screen N0 traffic based on the corresponding discrete point in the locked row vector to obtain the corresponding variance, and then replace the traffic of the corresponding discrete point;

[0121] A fifth analysis subunit, configured to, if the attribute combinations are all missing attributes, at this time, remove the corresponding column vector.

[0122] In this embodiment, since there are two traffic pairs in each column vector, and each traffic pair has a data attribute, therefore, there are two attributes in each column vector, and these two attributes form an attribute combination, and the attribute combination includes: correct attribute - correct attribute, missing attribute - missing attribute, correct attribute - missing attribute, missing attribute - correct attribute.

[0123] For example: there is an array matrix , and the corresponding attribute combination is , at this time, the second column vector is one correct attribute 02 and one missing attribute 12. At this time, if 0.6 is not regarded as a discrete point, at this time, the correct attribute closest to the missing attribute 12 is the correct attribute 11. Obtain the first average value of the traffic pair in the correct attribute 11, which is 0.5. At this time, replace 0.6.

[0124] If there is an array matrix , and the corresponding attribute combination is , at this time, the second column vector is a correct attribute 02 and a missing attribute 12. At this time, if 0.6 is not regarded as a discrete point, at this time, the missing attribute 12 is closest to the correct attribute 11. To obtain the first average value of the flow pairs in the correct attribute 11 is 0.5. However, the corresponding other flow pair is the missing attribute 01. At this time, the one closest to the missing attribute 01 is the correct attribute 03. Since 0.6 is in the second flow pair, so, at this time, lock the correct attribute 13 to obtain the second average value 0.5, which is the second average value of the required flow pair.

[0125] At this time, the third average value is 0.5.

[0126] In this embodiment, the discrete points with the same direction refer to that after discrete analysis, the two obtained discrete points are both above or below the corresponding discrete analysis standard. For example, in the same column vector: the first flow pair is 1, 1.2, and the second flow pair is 0.5, 0.6. Among them, 1.2 and 0.6 are discrete points respectively. At this time, it is regarded as having the same direction because 1.2 is above 1 and 0.6 is above 0.5.

[0127] For example, in the same column vector: the first flow pair is 1, 0.8, and the second flow pair is 0.5, 0.6. Among them, 0.8 and 0.6 are discrete points respectively. At this time, it is regarded as having different directions because 0.8 is below 1 and 0.6 is above 0.5.

[0128] In this embodiment, N0 is less than the number of moments in the matrix, which can be 5, and the number of moments is greater than 15, and the total duration of the acquisition moments can be 2 seconds, and it can be acquired 20 times in 2 seconds.

[0129] The beneficial effects of the above technical solution are: analyze the attribute combinations of each column vector in the matrix to determine the flows with discrete points and without discrete points under different combinations for reasonable replacement. Specifically, it is realized by the method of obtaining the average value of the closest distance and the correct attribute, ensuring the reliability of replacement.

[0130] The present invention provides a well-type furnace flow monitoring system based on PLC. The fourth analysis subunit includes:

[0131] A coefficient determination block for determining the value coefficient of the corresponding row vector according to the distribution of discrete points in each row vector of the flow pair corresponding to the missing attribute;

[0132] ;

[0133] ;

[0134] ;

[0135] Among them, Indicates the value coefficient corresponding to the row vector; Indicates the number of discrete points in the corresponding row vector; Indicates when the value function of the corresponding row vector; Indicates the number of vector intercept segments of adjacent discrete points existing in the corresponding row vector; Indicates the average value of all remaining flows except two discrete points in the i1-th vector intercept segment; Indicates the average flow rate of two discrete points in the i1-th vector intercept segment; Indicates the judgment function of the i1-th vector intercept segment; respectively indicate the flow rate of the first discrete point and the flow rate of the second discrete point in the i1-th vector intercept segment; max represents the maximum value symbol; Indicates the variance of all flows involved in the i1-th vector intercept segment; Indicates the average value of all remaining points except discrete points in the corresponding row vector;

[0136] Replacement block, used to replace the flow rate of the corresponding discrete point according to the variance of the corresponding row vector and the value coefficient of the corresponding row vector, and in combination with the flow rate L0 of the non-discrete point closest to the corresponding discrete point, according to to replace the flow rate of the corresponding discrete point, where Indicates the flow rate of the corresponding discrete point; Indicates the variance obtained by continuously screening N0 flow rates based on the corresponding discrete point.

[0137] In this embodiment, since the flow rate is directly measured by the sensor, relevant variance, mean and other results can be calculated.

[0138] In this embodiment, the non-discrete point closest to each discrete point is obtained based on the same row vector.

[0139] The beneficial effects of the above technical solution are: determining the value coefficient of each row vector according to the distribution of discrete points, and then combining the variance and the flow rate of the nearest non-discrete point to realize the reasonable replacement of the discrete point flow rate and ensure the reliability of the data.

[0140] The present invention provides a well-type furnace flow monitoring system based on a PLC. The PLC analysis module includes:

[0141] A data extraction unit for extracting the same group of data at the same aligned time point from the first data set and the second data set. Among them, the same group of data includes: two flow rates at the target inlet, two flow rates at the target outlet, and the temperature and pressure at the target auxiliary point;

[0142] A model analysis unit, configured to input the process stage where the pit furnace is located and the temperature and pressure in the same group of data into a loss analysis model to obtain a theoretical loss;

[0143] A label assignment unit, configured to, if the first difference between the average values of the two flows at the target inlet and the average values of the two at the target outlet is less than or equal to the sum of the theoretical loss and the normal usage flow rate at the corresponding process stage, assign a first adjustment label to the control valve at the target outlet for the corresponding alignment time point;

[0144] Otherwise, assign a second adjustment label to the control valve at the target inlet for the corresponding alignment time point;

[0145] A PID adjustment unit, configured to determine the control valve to be adjusted and the adjustment opening degree of the control valve to be adjusted based on the PID control algorithm according to the adjustment labels sequentially obtained and the second differences between the first difference and the sum corresponding to each label, so as to achieve adjustment.

[0146] In this embodiment, the loss analysis model is trained based on the pit furnace in different process stages, the temperature and pressure for this stage, and the analysis results of experts on the temperature and pressure in this process stage (air loss based on temperature and pressure) as samples for a neural network model (CNN model), and the number of training samples is greater than 1000. Therefore, the theoretical loss can be directly obtained. For example, in the heat preservation stage, according to the temperature and pressure conditions, the model calculates that the theoretical flow loss at this time is 1 cubic meter per hour.

[0147] It should be noted that the pit furnace includes a heating stage, a heat preservation stage, a cooling stage, etc. The loss results involved in temperature and pressure in different stages are different, but there are known samples determined by experts to directly train the model.

[0148] In this embodiment, for example, the sum of the normal usage flow rates in the heat preservation stage is 10 cubic meters per hour. If the first difference is less than or equal to 1 cubic meter per hour + 10 cubic meters per hour, assign a first adjustment label to the outlet.

[0149] Otherwise, assign a second adjustment label to the inlet.

[0150] During the operation of the pit furnace, adjustment labels will be sequentially assigned to the control valve according to data such as flow rate, temperature, and pressure at different times. These labels record the state that the control valve should be in or the operation direction that needs to be carried out at each moment. For example, within a period of time, a plurality of first adjustment labels and second adjustment labels are sequentially obtained, corresponding to different time points and control valves respectively.

[0151] For each adjustment label, there is a corresponding first difference (the difference between the average of the target inlet and outlet flow rates) and the sum of the theoretical loss and the normal operating flow rate of the corresponding process stage. The second difference is the value obtained by subtracting this sum from the first difference. For example, at a certain moment, the corresponding first difference is 3 cubic meters per hour, and the sum of the theoretical loss and the normal operating flow rate is 2.5 cubic meters per hour, then the second difference is 3 - 2.5 = 0.5 cubic meters per hour. This second difference can reflect the deviation degree between the current flow state and the desired flow state.

[0152] The PID control algorithm is a commonly used feedback control algorithm. Through the calculations of three links: proportional (P), integral (I), and derivative (D), it adjusts the control quantity according to the error of the system to make the system reach a stable state. In this context, the PID control algorithm determines how to adjust the opening degree of the regulating valve based on the adjustment label and the second difference to achieve precise control of the flow rate of the pit furnace. For example, if the second difference is large, the PID algorithm may quickly increase or decrease the opening degree of the regulating valve according to the proportional link, and at the same time use the integral link to eliminate the long-term error accumulation. By predicting the change trend of the error through the derivative link, it makes adjustments in advance to make the flow rate quickly stabilize within the desired range.

[0153] Based on the adjustment label and the calculation result of the PID control algorithm, determine the regulating valve that needs to be adjusted. It may be the regulating valve at the target inlet or the regulating valve at the target outlet, depending on the actual flow deviation situation and the control strategy. For example, if the second difference is large multiple times and the regulating valve at the target inlet is assigned the second adjustment label, then determine the regulating valve at the target inlet as the valve to be adjusted.

[0154] The adjustment amplitude that the regulating valve to be adjusted needs to be adjusted, which is calculated by the PID control algorithm. For example, through the PID algorithm calculation, it is determined that the regulating valve to be adjusted (assuming it is the regulating valve at the target inlet) needs to reduce the opening degree from the current 50% to 40% to reduce the inlet flow rate and make the flow rate of the system reach a balanced state and meet the process requirements.

[0155] The beneficial effects of the above technical solution are: determining the theoretical loss based on temperature and pressure, and then determining the label by comparing the size of the first difference with the sum of the theoretical loss and the normal operating flow rate, effectively providing a data basis for the implementation of the PID control algorithm, determining the opening degree, realizing the adjustment, and ensuring the high efficiency of the pit furnace operation.

[0156] The present invention provides a pit furnace flow monitoring system based on PLC. The safety protection module includes:

[0157] An alarm unit, which is used to match the second difference with the difference - comparison table to obtain alarm information and give an alarm reminder;

[0158] A continuous control unit is used to adjust each second difference according to the control result. If more than half of the adjusted second differences are still greater than 0, at this time, it is determined based on the PLC analysis module that continuous control of the valve to be adjusted is required.

[0159] In this embodiment, the difference - comparison table contains alarm information matching double differences (the first difference, the second difference). For example, when the second difference is between 0 - 0.5 cubic meters per hour, an alarm message of "Flow is slightly abnormal, please pay attention to observation" is issued; when the second difference is greater than 0.5 cubic meters per hour and less than or equal to 1 cubic meter per hour, an alarm message of "Flow is moderately abnormal, further inspection is required" is issued; when the second difference is greater than 1 cubic meter per hour, an alarm message of "Flow is severely abnormal, take immediate measures" is issued.

[0160] In this embodiment, the alarm reminder is an operation to convey the alarm information to relevant personnel through means such as sound, light, text message, pop - up window, etc.

[0161] In this embodiment, through the PID control algorithm, the opening of the regulating valve at the target inlet is adjusted from 60% to 50%. This is a control result. At the same time, the flow rate may also drop from the original 15 cubic meters per hour to 13 cubic meters per hour. After one adjustment, the second difference at a certain time point is recalculated and found to have dropped from the original 1.5 cubic meters per hour to 1 cubic meter per hour. This shows that the adjustment has played a certain role, and the number of times the adjustment has played a role is 10 times and the captured control results are 18 times. At this time, less than half of the adjusted second differences are less than 0. At this time, continuous control adjustment is not required.

[0162] If the number of times the adjustment has played a role is 7 times, at this time, more than half of the adjusted second differences are still greater than 0. At this time, continuous adjustment is required.

[0163] The beneficial effects of the above - mentioned technical solution are: adjusting the second difference based on the control result and combining with the number of adjusted second differences greater than 0 to analyze whether continuous control is required, ensuring the control accuracy. And when the PLC analysis module determines that continuous control is required, it will send a corresponding control signal to the valve to be adjusted to further adjust the opening of the regulating valve in an attempt to make the system flow rate reach a stable state and meet the process requirements.

[0164] The present invention provides a control method for a well - type furnace flow monitoring system based on PLC, as Figure 2 shown, including:

[0165] Step 1: Perform data acquisition on the pit furnace based on the first sensor group arranged at the target inlet and target outlet of the pit furnace to obtain a first data set, where the first sensor group is related to a flow sensor;

[0166] Step 2: Perform data acquisition based on the second sensor group arranged at the target auxiliary point of the pit furnace to obtain a second data set, where the second sensor group is related to a pressure sensor and a temperature sensor, and the acquisition time of the second data set is consistent with that of the first data set;

[0167] Step 3: Preprocess and comprehensively analyze the first data set and the second data set to determine the valves to be adjusted, and then control each valve to be adjusted based on the PID control algorithm;

[0168] Step 4: During the preprocessing of the first data set and the second data set, perform comparative analysis with the corresponding alarm constraints to achieve alarm reminders. At the same time, positively eliminate the alarm reminders according to the control results, and determine whether it is necessary to continue controlling the valves to be adjusted;

[0169] Step 5: Real-time display the acquisition results, control results, and alarm reminder results.

[0170] The beneficial effects of the above technical solution are as follows: By setting up sensor groups to collect flow rate, temperature, and pressure, it avoids control errors caused by overly single data, improves the actual reliability of flow rate acquisition, and then determines the valves to be adjusted through analysis and processing of the data sets to achieve precise control. Furthermore, through comparative analysis, positive elimination, and visual display, it facilitates continuous precise control and is convenient for personnel to view.

[0171] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A PLC-based pit furnace flow monitoring system, characterized in that: include: A first data acquisition module, configured to acquire data from the pit furnace based on a first sensor group disposed at a target inlet and a target outlet of the pit furnace to obtain a first data set, wherein the first sensor group is associated with a flow sensor; A second data acquisition module is used to acquire data based on a second sensor group arranged at a target auxiliary point of the pit furnace to obtain a second data set, wherein the second sensor group is related to a pressure sensor and a temperature sensor, and the acquisition time corresponding to the second data set is consistent with that of the first data set; A PLC analysis module, used to pre-process and comprehensively analyze the first data set and the second data set, determine the valve to be regulated, and then control each valve to be regulated based on a PID control algorithm; A safety protection module, used for comparing and analyzing the first data set and the second data set with the corresponding alarm constraints during the preprocessing process to realize alarm reminders, and at the same time, positively eliminating the alarm reminders according to the control results, and feeding back the positive elimination results to the PLC analysis module to determine whether it is necessary to continue to control the regulating valve; The visualization module is used to display the collection results of the data collection module, the control results of the PLC analysis module and the alarm reminder results of the safety protection module in real time.

2. The PLC-based pit furnace flow monitoring system according to claim 1 is characterized in that: The first data acquisition module comprises: A first constructing unit, configured to construct a first array based on data collection results of a first sensor group disposed at a target entrance; A second construction unit, configured to construct a second array based on data collection results of a second sensor group disposed at the target outlet; An alignment processing unit, configured to align the first array with the second array according to a flow delay time from a target inlet to a target outlet of the pit furnace to obtain an array matrix; An attribute analysis unit, used for analyzing a first data attribute of a first flow pair and a second data attribute of a second flow pair in each column vector in the array matrix, wherein the data attributes are a lost attribute and a correct attribute; A replacement unit, configured to perform discrete analysis on each row vector in the array matrix to lock discrete points, and replace the discrete points according to a first distribution of discrete points in the first flow pair and a second distribution of discrete points in the second flow pair, in combination with the first data attribute and the second data attribute; A first set determination unit, used for obtaining a new matrix according to the replacement result, and considering all data in the new matrix as a first data set; The target inlet and the target outlet are each provided with a first sensor group, and the first sensor group includes two flow sensors, and the two flow sensors are arranged in front and back positions, wherein the distance between the first flow sensor and the second flow sensor is 3 cm.

3. The PLC-based pit furnace flow monitoring system according to claim 2 is characterized in that: The attribute analysis unit comprises: A reference acquisition subunit, used to acquire the current opening of the target valve associated with the target inlet at the time of acquisition of each of the first flow pairs, and obtain a first reference flow in combination with a preset input flow; a calculation subunit, configured to calculate a first difference and a second difference between a first flow rate and a second flow rate in a first flow pair and a first reference flow rate, respectively, and if the first difference and the second difference respectively satisfy corresponding preset difference constraints, then it is determined that a first data attribute corresponding to the first flow pair is a correct attribute; Otherwise, it is determined that the first data attribute corresponding to the first traffic pair is a loss attribute.

4. The PLC-based pit furnace flow monitoring system according to claim 2 is characterized in that: The replacement unit comprises: A combination determination subunit, used to determine the attribute combination of each column vector in the array matrix; If the attribute combination is two correct attributes, then the corresponding column vector is kept unchanged; A first analysis subunit is used for, if the attribute combination is a correct attribute and a missing attribute, and there is no discrete point in the flow pair corresponding to the missing attribute, then screening the correct attribute closest to the corresponding missing attribute, if the two flow pairs in the column vector corresponding to the correct attribute with the closest distance are both correct attributes, then replacing the flow whose difference in the flow pair of the corresponding missing attribute does not satisfy the corresponding preset difference constraint according to the first average value of the flow pair of the correct attribute with the closest distance; A second analysis subunit is used for, if another flow pair in the column vector corresponding to the closest correct attribute is a lost attribute, obtaining the correct attribute closest to the lost attribute of the other flow pair, and obtaining a second average value of the required flow pairs involved in the column corresponding to the closest correct attribute of the lost attribute of the other flow pair; The first average value and the second average value are averaged to obtain a third average value, so as to replace the flow whose difference in the flow pair with the corresponding loss attribute does not satisfy the corresponding preset difference constraint; A third analysis subunit is configured to keep the two discrete points unchanged if the attribute combination is a correct attribute and a lost attribute, and there are two discrete points with the same discrete directions in the flow pair corresponding to the lost attribute; A fourth analysis subunit is used for, if the attribute combination is one correct attribute and one missing attribute, and there are two discrete points with inconsistent discrete directions or one discrete point in the flow pair corresponding to the missing attribute, then, locking the corresponding row vector of the flow pair of the missing attribute and continuously screening N0 flows based on the corresponding discrete points in the locked row vector to obtain the corresponding variance, and then replacing the flow of the corresponding discrete point; The fifth analyzing subunit is used for removing the corresponding column vector if all attribute combinations are missing attributes.

5. The PLC-based pit furnace flow monitoring system according to claim 4 is characterized in that: The fourth analysis subunit comprises: A coefficient determination block, used to determine the value coefficient of the corresponding row vector according to the distribution of discrete points in each row vector in the flow pair corresponding to the loss attribute; ； ； ； in, represents the value coefficient of the corresponding row vector; Represents the number of discrete points in the corresponding row vector; Indicates when When , the value function of the corresponding row vector; The number of vector intercept segments representing the adjacent discrete points where the corresponding row vector exists; represents the average value of all remaining flows except two discrete points in the i1th vector intercept segment; represents the average flow rate of two discrete points in the i1th vector intercept segment; represents the judgment function of the i1th vector intercept segment; They represent the flow rate of the first discrete point and the flow rate of the second discrete point in the i1th vector interception segment respectively; max represents the maximum value symbol; represents the variance of all flows involved in the i1th vector intercept segment; Represents the average value of all remaining points except discrete points in the corresponding row vector; The replacement block is used to calculate the variance of the corresponding row vector and the value coefficient of the corresponding row vector, and to calculate the flow rate L0 of the non-discrete point closest to the corresponding discrete point according to Replace the flow of the corresponding discrete points, where Represents the flow rate corresponding to the discrete point; It represents the variance obtained by continuously screening N0 flow rates based on the corresponding discrete points.

6. The PLC-based pit furnace flow monitoring system according to claim 1 is characterized in that: The PLC analysis module comprises: A data extraction unit, used to extract the same group of data at the same alignment time point from the first data set and the second data set, wherein the same group of data includes: two flow rates of a target inlet, two flow rates of a target outlet, and a temperature and a pressure of a target auxiliary point; A model analysis unit, used for inputting the process stage of the pit furnace and the temperature and pressure in the same group of data into the loss analysis model to obtain theoretical loss; a label assigning unit, configured to assign a first regulating label of the regulating valve of the target outlet to the corresponding alignment time point if a first difference between an average value of the two flow rates of the target inlet and the two average values ​​of the target outlet is less than or equal to a sum of a theoretical loss and a normal use flow rate of a corresponding process stage; Otherwise, assigning a second regulating tag of the regulating valve of the target inlet to the corresponding aligned time point; The PID adjustment unit is used to determine the valve to be adjusted and the adjustment opening of the valve to be adjusted based on the PID control algorithm according to the adjustment tags obtained in sequence and the first difference corresponding to each tag and the second difference of the sum to achieve adjustment.

7. The PLC-based pit furnace flow monitoring system according to claim 6 is characterized in that: The security protection module comprises: An alarm unit, used for obtaining alarm information and giving an alarm reminder by matching the second difference with a difference-comparison table; A control unit is continued to adjust each second difference according to the control result. If more than half of the adjusted second differences are still greater than 0, then based on the PLC analysis module, it is determined that the regulating valve needs to be continued to be controlled.

8. A control method for a pit furnace flow monitoring system based on PLC, characterized in that: include: Step 1: collecting data from the pit furnace based on a first sensor group disposed at a target inlet and a target outlet of the pit furnace to obtain a first data set, wherein the first sensor group is related to a flow sensor; Step 2: Collecting data based on a second sensor group arranged at a target auxiliary point of the pit furnace to obtain a second data set, wherein the second sensor group is associated with a pressure sensor and a temperature sensor, and the second data set has the same collection time as the first data set; Step 3: pre-processing and comprehensively analyzing the first data set and the second data set to determine the valve to be regulated, and then controlling each valve to be regulated based on the PID control algorithm; Step 4: During the preprocessing of the first data set and the second data set, a comparison analysis is performed with the corresponding alarm constraints to implement an alarm reminder. At the same time, the alarm reminder is positively eliminated according to the control result, and it is determined whether the regulating valve needs to continue to be controlled; Step 5: Display the acquisition results, control results and alarm reminder results in real time.

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