Analog quantity control method based on distributed control system and related device

Abstract

The application discloses an analog quantity control method based on a distributed control system, which can be applied to the field of automatic control and comprises the following steps: acquiring a plurality of analog quantity control intervals, analog quantity values, analog quantity change rates and analog quantity change trend inflection points; determining an analog quantity regulating valve control rule based on the analog quantity value at zero time; and controlling the opening degree of the analog quantity regulating valve based on the analog quantity regulating valve control rule, the analog quantity control interval in which the current analog quantity value is located, the analog quantity change rate and the analog quantity change trend inflection point. Thus, the analog quantity control intervals are divided, different analog quantity regulating valve opening degrees are configured for different combinations of the analog quantity change rate and the analog quantity change trend inflection point in each analog quantity control interval, the adjustment requirement of the analog quantity value under different conditions can be more accurately met, the control precision, the control efficiency and the control stability of the analog quantity are improved, and the stability of product quality is further improved.

Description

Technical Field

[0001] This application relates to the field of automatic control technology, and in particular to an analog quantity control method and related apparatus based on a distributed control system. Background Technology

[0002] With the development of industrial production automation, distributed control systems (DCS) are widely used to control and monitor analog quantities in various processes.

[0003] Currently, feedback control mechanisms, such as PID control, are commonly used in DCS systems to control and monitor analog quantities. However, changes in analog quantities such as temperature, pressure, and flow rate often exhibit complex nonlinear characteristics, making the control effect of feedback control mechanisms unsatisfactory. Furthermore, due to the hysteresis effect of DCS systems in responding to changes in analog quantities, even advanced model predictive control strategies struggle to achieve precise control of critical analog quantities, thus affecting production stability and efficiency, and consequently, product quality.

[0004] Therefore, how to achieve more precise control of analog quantities through a DCS system has become a problem that needs to be solved. Summary of the Invention

[0005] To address the aforementioned issues, this application provides an analog quantity control method and related apparatus based on a distributed control system, which can enable more precise control of analog quantities through a DCS system.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, embodiments of this application provide an analog control method based on a distributed control system, the method comprising:

[0008] Acquire multiple analog quantity control ranges, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends;

[0009] Based on the analog quantity value at time zero, the control rules for the analog quantity regulating valve are determined; the control rules for the analog quantity regulating valve include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening degree of the analog quantity regulating valve in different analog quantity control intervals.

[0010] The opening degree of the analog quantity regulating valve is controlled based on the control rules of the analog quantity regulating valve, the analog quantity control interval where the current analog quantity value is located, the rate of change of the analog quantity, and the inflection point of the trend of the analog quantity change.

[0011] Optionally, the plurality of analog quantity control ranges include:

[0012] The outer positive buffer, positive buffer, target control area, negative buffer, and outer negative buffer; the minimum value of the outer positive buffer is greater than the maximum value of the positive buffer; the minimum value of the positive buffer is greater than the maximum value of the target control area; the minimum value of the target control area is greater than the maximum value of the negative buffer; the minimum value of the negative buffer is greater than the maximum value of the outer negative buffer.

[0013] Optionally, determining the analog quantity regulating valve control rule based on the analog quantity control range in which the analog quantity value lies and the analog quantity change rate includes:

[0014] If the analog value at time zero is less than the target control value, then the analog regulating valve control rule is determined to be the first control rule; the target control value is the median value of the target control region.

[0015] If the analog value at time zero is greater than the target control value, then the analog regulating valve control rule is determined to be the second control rule.

[0016] Optionally, if the analog value at time zero is less than the target control value, then controlling the opening of the analog regulating valve based on the analog regulating valve control rules, the analog control interval where the current analog value is located, the analog change rate, and the inflection point of the analog change trend includes:

[0017] If the current analog value is in the outer negative buffer, the negative buffer, or the target control area, the opening of the first regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the first regulating valve is used to increase the analog value.

[0018] If the current analog value is in the outer positive buffer or the positive buffer, the opening of the second regulating valve is controlled based on the analog control range where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the second regulating valve is used to reduce the analog value.

[0019] Optionally, if the current analog value is within the outer negative buffer zone, the opening degree of the first regulating valve is selected from 20% to 80%.

[0020] If the current analog value is in the negative buffer or the target control area, the opening degree of the first regulating valve is selected from 0% to 10%.

[0021] If the current analog value is within the positive buffer or the outer positive buffer, then the first regulating valve is closed and the second regulating valve is opened, wherein the opening degree of the second regulating valve is selected from 0% to 20%.

[0022] Optionally, if the analog value at time zero is greater than the target control value, then controlling the opening of the analog regulating valve based on the analog regulating valve control rules, the analog control interval where the current analog value is located, the analog change rate, and the inflection point of the analog change trend includes:

[0023] If the current analog value is in the outer negative buffer or the negative buffer, the opening of the first regulating valve is controlled based on the analog control range where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value.

[0024] If the current analog value is in the outer positive buffer zone, the positive buffer zone, or the target control zone, the opening of the second regulating valve is controlled based on the analog control zone where the current analog value is located, the analog change rate, and the inflection point of the analog change trend.

[0025] Optionally, if the current analog value is within the outer positive buffer zone, the opening degree of the second regulating valve is selected from 20% to 80%.

[0026] If the current analog value is within the target control zone or the positive buffer zone, the opening degree of the second regulating valve is selected from 0% to 10%.

[0027] If the current analog value is in the outer negative buffer or the negative buffer, then the second regulating valve is closed and the first regulating valve is opened, wherein the opening degree of the first regulating valve is selected from 0% to 20%.

[0028] Secondly, embodiments of this application provide an analog quantity control device based on a distributed control system, the device comprising: an acquisition module, a determination module, and a control module;

[0029] The acquisition module is used to acquire multiple analog quantity control ranges, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends;

[0030] The determining module is used to determine the control rules of the analog quantity regulating valve based on the analog quantity value at time zero; the control rules of the analog quantity regulating valve include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening degree of the analog quantity regulating valve within different analog quantity control intervals.

[0031] The control module is used to control the opening degree of the analog quantity regulating valve based on the control rules of the analog quantity regulating valve, the analog quantity control interval where the current analog quantity value is located, the rate of change of the analog quantity, and the inflection point of the trend of the analog quantity change.

[0032] Thirdly, embodiments of this application provide a controller for a distributed control system, the controller comprising: a memory and a processor;

[0033] The memory is used to store program code and transmit the program code to the processor;

[0034] The processor is configured to execute, according to the program code, the steps of the analog control method based on a distributed control system as described in any one of the first aspects.

[0035] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program. When the computer program is run on a controller applied to a distributed control system, the controller applied to the distributed control system executes the steps of the analog control method based on the distributed control system as described in any one of the first aspects.

[0036] Compared with the prior art, this application has the following advantages:

[0037] This application provides an analog quantity control method based on a distributed control system. The method includes: acquiring multiple analog quantity control intervals, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends; determining analog quantity control rules based on the analog quantity value at time zero; the analog quantity control rules include the correspondence between the analog quantity change rate and the inflection point of the analog quantity change trend and the opening degree of the analog quantity control valve within different analog quantity control intervals; and controlling the opening degree of the analog quantity control valve based on the analog quantity control rules, the analog quantity control interval where the current analog quantity value is located, the analog quantity change rate, and the analog quantity change trend inflection point. Therefore, by dividing multiple analog quantity control intervals and configuring different analog quantity control valve opening degrees for different combinations of analog quantity change rates and inflection points of analog quantity change trends within each analog quantity control interval, the adjustment requirements for analog quantity values ​​under different conditions can be met more accurately, improving the control accuracy, control efficiency, and control stability of the analog quantity, thereby improving the stability of product quality. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A flowchart of an analog quantity control method based on a distributed control system is provided for an embodiment of this application;

[0040] Figure 2 This application provides a schematic diagram of analog quantity control interval division.

[0041] Figure 3 A schematic diagram of the first control rule provided for an embodiment of this application;

[0042] Figure 4 A schematic diagram of the second control rule provided in the embodiments of this application;

[0043] Figure 5 A schematic diagram of an analog quantity control device based on a distributed control system provided in this application embodiment;

[0044] Figure 6 This is a controller structure diagram for a distributed control system provided in an embodiment of this application. Detailed Implementation

[0045] The analog quantity control method and related device based on distributed control system provided in this application can be used in the field of automatic control. The above is only an example and does not limit the application field of the analog quantity control method and related device based on distributed control system provided in this application.

[0046] The terms "first," "second," "third," and "fourth," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0047] In the embodiments of this application, the terms "as an example" or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "as an example" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of terms such as "as an example" or "for example" is intended to present the relevant concepts in a specific manner.

[0048] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0049] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0050] See Figure 1 The figure is a flowchart of an analog control method based on a distributed control system provided in an embodiment of this application. The method includes:

[0051] S101: Obtain multiple analog quantity control ranges, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends.

[0052] For example, an analog quantity is a continuously changing quantity or signal in a DCS system. For instance, it could be a process parameter such as temperature, pressure, or flow rate, or a user-defined variable used in the DCS system for auxiliary control. Analog quantity values ​​can be obtained by monitoring field conditions through the DCS system. The rate of change of the analog quantity is the numerical change in the analog quantity value per unit time; for example, it could be the numerical change in the analog quantity value within one minute. The inflection point of the analog quantity change trend is the point where the trend of the analog quantity value changes from increasing to decreasing or from decreasing to increasing.

[0053] Optionally, see Figure 2 The figure is a schematic diagram of analog quantity control interval division provided in an embodiment of this application. Multiple analog quantity control intervals may include: outer positive buffer, positive buffer, target control area, negative buffer and outer negative buffer.

[0054] Among them, the minimum value of the outer positive buffer is greater than the maximum value of the positive buffer; the minimum value of the positive buffer is greater than the maximum value of the target control area; the minimum value of the target control area is greater than the maximum value of the negative buffer; and the minimum value of the negative buffer is greater than the maximum value of the outer negative buffer.

[0055] As an example, the range of the outer positive buffer is [SV+PC, +∞); the range of the positive buffer is (SV+JD, SV+PC); the target control region is [SV-JD, SV+JD]; the negative buffer is (SV-PC, SV-JD); and the outer negative buffer is (-∞, SV-PC]; where SV is the target control value, i.e., the median of the target control region, PC is the allowable deviation of the analog quantity, JD is the accuracy of the analog quantity, and AI is the analog quantity value. For example, if the allowable range of the process parameters of the analog quantity is 45±5 and the measurement accuracy is ±1, then SV is 45, PC is 5, and JD is 1.

[0056] S102: Determine the control rules for the analog regulating valve based on the analog value at time zero.

[0057] For example, the analog value at time zero can be the analog value monitored by the DCS system at the start of the production process, the analog value monitored by the DCS system at the start of the preset calibration cycle, or the analog value monitored by the DCS system at the set monitoring start time, etc.

[0058] Optionally, the analog control valve control rule includes a first control rule and a second control rule. The analog value at time zero is compared with the target control value. If the analog value at time zero is less than the target control value, the analog control valve control rule is determined to be the first control rule; if the analog value at time zero is greater than the target control value, the analog control valve control rule is determined to be the second control rule. Therefore, by determining the applied analog control valve control rule based on the relationship between the analog value at time zero and the target control value, a suitable analog control valve control rule can gradually bring the analog value closer to the target control value, making it easier to ultimately control the analog value within the target control range and achieve a more ideal control state.

[0059] S103: Based on the analog quantity control valve control rules, the analog quantity control range where the current analog quantity value is located, the analog quantity change rate, and the inflection point of the analog quantity change trend, control the opening degree of the analog quantity control valve.

[0060] For example, the analog quantity control rules include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening degree of the analog quantity control valve within different analog quantity control intervals. For example, in the first control rule, if the analog quantity value is within the negative buffer and the rate of change of the analog quantity BHL≤0.05, the corresponding opening degree of the analog quantity control valve is 10% of the opening degree of the first control valve; wherein, the opening of the first control valve is used to increase the analog quantity value, and the larger the opening degree of the first control valve, the faster the rate of increase of the analog quantity value.

[0061] Optionally, a control cycle can be preset. Each control cycle controls the opening of the analog control valve based on the analog control valve control rules, the analog control range where the current analog value is located, the analog change rate, and the inflection point of the analog change trend. For example, the control cycle can be 500ms.

[0062] Therefore, in this embodiment of the application, by dividing multiple analog quantity control intervals and configuring different analog quantity regulating valve openings for different combinations of analog quantity change rates and inflection points of analog quantity change trends within each analog quantity control interval, the adjustment requirements for analog quantity values ​​under different conditions can be met more accurately, thereby improving the control accuracy, control efficiency and control stability of analog quantities, and thus improving the stability of product quality.

[0063] In other embodiments provided in this application, when applying the first control rule, if the current analog value is in the outer negative buffer, negative buffer, or target control region, the opening of the first regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the analog value's change trend; if the current analog value is in the outer positive buffer or positive buffer, the opening of the second regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the analog value's change trend. The first regulating valve is used to increase the analog value; the second regulating valve is used to decrease the analog value.

[0064] Optionally, in the first control rule, if the current analog value is in the outer negative buffer zone, the opening degree of the first regulating valve is selected from 20% to 80%; if the current analog value is in the negative buffer zone or the target control zone, the opening degree of the first regulating valve is selected from 0% to 10%; if the current analog value is in the positive buffer zone or the outer positive buffer zone, the first regulating valve is closed and the second regulating valve is opened, with the opening degree of the second regulating valve selected from 0% to 20%.

[0065] See Figure 3 This figure is a schematic diagram of the first control rule provided in an embodiment of this application.

[0066] The first control rule applies when the value of the controlled analog quantity at zero time is less than the target control value SV. By applying the first control rule, the analog quantity value in the outer negative buffer can pass through the three regions of the outer negative buffer, the negative buffer and the target control region in sequence, and finally stay in the target control region, so as to achieve a more ideal control state.

[0067] For example, the first control rule may include 13 logical sequence numbers, as follows:

[0068] If the current analog value is in the outer negative buffer and the analog change rate BHL is less than 1.0, then execute logic sequence number 13 to open the first regulating valve to increase the analog value. The setting value of the opening of the first regulating valve can be selected from 40% to 80% so that the analog value with a large deviation from the target control value can approach the target control value more quickly.

[0069] If the current analog value is in the outer negative buffer and the analog change rate BHL is greater than or equal to 1.0, then logic sequence number 12 is executed to control the first regulating valve to reduce its opening. At this time, the analog change rate is large and the rise speed is too fast, so the opening of the first regulating valve can be reduced in advance, thereby reducing the analog change rate. This allows the analog value to approach the target control value more smoothly, reducing situations where the analog value cannot stay in the target control area due to over-adjustment and passes through the positive buffer or even the outer positive buffer. For example, the set value of the first regulating valve opening can be selected from 20% to 40%.

[0070] If the current analog value is in the negative buffer and the analog change rate BHL is less than or equal to 0.05, then execute logic sequence 11 to control the opening of the first regulating valve to 10%. At this time, the analog change rate is small, but it is within the deviation range. A slightly larger opening of the first regulating valve can be used to control the analog change rate within the range of (0.05, 0.5) so that the analog value can continue to approach the target control value.

[0071] If the current analog value is in the negative buffer and the analog change rate BHL is within the range of (0.05, 0.5), then logic sequence number 10 is executed to control the opening of the first regulating valve to 5%. At this time, the analog change rate can meet the requirement of making the analog value approach the target control value smoothly and relatively quickly. Therefore, the opening of the first regulating valve can be set to 5% to maintain the current analog change rate as much as possible.

[0072] If the current analog value is in the negative buffer and the analog change rate BHL is greater than or equal to 0.1, then logic sequence number 9 is executed to control the opening of the first regulating valve to 0%. At this time, the analog value is relatively close to the target control value. When BHL is greater than or equal to 0.1, there is a risk of over-adjustment. The opening of the first regulating valve can be further reduced, or even the first regulating valve can be closed, that is, the opening of the first regulating valve is controlled to 0%.

[0073] If the current analog value is within the target control range and the analog change rate BHL is greater than or equal to 0.5, then execute logic sequence 8 to control the opening of the first regulating valve to 0%. If the current analog value is already within the target control range, then the analog value and the target control value are very close. The difference between the two may be affected by the measurement accuracy. In this case, it is necessary to maintain the current analog value. Preferably, maintaining BHL within the range of [-0.1, 0.1] can be taken as the target. If BHL is greater than or equal to 0.5, then the first regulating valve needs to be closed in advance to slow down the upward trend of the analog value.

[0074] If the current analog value is within the target control range, the analog change rate BHL is within the range of [-0.1, 0.1], and the inflection point DD of the analog change trend is less than 0, then logic sequence 7 is executed to control the first regulating valve. The opening degree of the first regulating valve can be selected from 3% to 5%. At this time, the trend of the analog value changes from rising to falling, so it is necessary to increase the opening degree of the first regulating valve in advance to maintain the analog value within the target control range.

[0075] If the current analog value is within the target control zone, the analog change rate BHL is within the range of [-0.1, 0.1], and the inflection point DD of the analog change trend is greater than 0, then logic sequence number 6 is executed to control the opening of the first regulating valve to 0%. At this time, the trend of the analog value changes from decreasing to increasing, so it is necessary to reduce the opening of the first regulating valve in advance to maintain the analog value within the target control zone.

[0076] If the current analog value is within the target control range and the analog change rate BHL is less than -0.1, then execute logic sequence 5 to control the opening of the first regulating valve to 10%. When BHL is less than -0.1, the analog value decreases rapidly, and the opening of the first regulating valve needs to be increased in advance to maintain the analog value within the target control range.

[0077] If the current analog value is in the positive buffer, the analog change rate BHL is greater than 0.01, and the inflection point of the analog change trend DD is greater than 0, then execute logic sequence number 4 to close the first regulating valve and open the second regulating valve. The opening degree of the second regulating valve can be selected from 0% to 5%. At this time, the analog value rises to the positive buffer and the rise rate is relatively fast, so the second regulating valve needs to be opened to reduce the analog value.

[0078] If the current analog value is in the positive buffer, the analog change rate BHL is greater than or equal to -0.05, and the inflection point DD of the analog change trend is less than 0, then execute logic sequence 3 to close the first and second regulating valves. At this time, the trend of the analog value changes from rising to falling, allowing the analog regulating valves to be closed in advance.

[0079] If the current analog value is within the outer positive buffer and the inflection point DD of the analog value's change trend is less than 0, then execute logic sequence number 2 to close the first and second regulating valves. At this time, the trend of the analog value changes from rising to falling, allowing the analog regulating valves to be closed in advance.

[0080] If the current analog value is within the outer positive buffer zone and no inflection point DD appears in the analog value change trend, then logic sequence 1 is executed to control the second regulating valve. The opening degree of the second regulating valve can be selected from 5% to 15%. At this time, the analog value is outside the specified deviation and needs to be reduced through the second regulating valve.

[0081] It is understood that the above settings for the analog quantity change rate BHL and the analog quantity regulating valve opening are merely examples, and those skilled in the art can flexibly set them according to actual needs.

[0082] In other embodiments provided in this application, when applying the second control rule, if the current analog value is in the outer negative buffer or the negative buffer, the opening of the first regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; if the current analog value is in the outer positive buffer, the positive buffer, or the target control area, the opening of the second regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value.

[0083] Optionally, in the second control rule, if the current analog value is in the outer positive buffer zone, the opening degree of the second regulating valve is selected from 20% to 80%; if the current analog value is in the target control zone or positive buffer zone, the opening degree of the second regulating valve is selected from 0% to 10%; if the current analog value is in the outer negative buffer zone or negative buffer zone, the second regulating valve is closed and the first regulating valve is opened, with the opening degree of the first regulating valve selected from 0% to 20%.

[0084] See Figure 4 This figure is a schematic diagram of the second control rule provided in an embodiment of this application.

[0085] The second control rule applies to situations where the value of the controlled analog quantity at zero time is greater than the target control value SV. By applying the second control rule, the analog quantity value in the outer positive buffer can pass through the three regions of the outer positive buffer, the positive buffer, and the target control region in sequence, and finally stay in the target control region, so as to achieve a more ideal control state.

[0086] For example, with Figure 3 Similar to the first control rule shown, the second control rule can also include 13 logical numbers, as detailed below:

[0087] If the current analog value is in the outer positive buffer and the analog change rate BHL is greater than or equal to -1.0, then execute logic sequence number 1 to open the second regulating valve to reduce the analog value. The set value of the second regulating valve opening can be selected from 40% to 80% so that the analog value with a large deviation from the target control value can approach the target control value more quickly. At this time, the opening of the analog regulating valve can also be the initial opening.

[0088] If the current analog value is within the outer positive buffer zone and the analog change rate BHL is less than -1.0, then logic sequence 2 is executed to control the second regulating valve to reduce its opening. At this time, the analog value decreases too quickly, so the opening of the second regulating valve can be reduced in advance, thereby reducing the absolute value of the analog change rate. This allows the analog value to approach the target control value more smoothly, reducing situations where over-adjustment causes the analog value to fail to remain within the target control zone and instead passes through the negative buffer zone or even the outer negative buffer zone. For example, the setpoint for the opening of the first regulating valve can be selected from 20% to 40%.

[0089] If the current analog value is in the positive buffer and the analog change rate BHL is less than or equal to -0.05, then execute logic sequence 3 to control the opening of the second regulating valve to 0%. At this time, the analog value drops rapidly and is already within the allowable deviation range, so the opening of the second regulating valve can be closed in advance to control the analog change rate within the range of (-0.05, 0).

[0090] If the current analog value is in the negative buffer and the analog change rate BHL is within the range of (-0.05, 0), then logic sequence 4 is executed, which controls the second regulating valve. The opening degree of the second regulating valve can be selected from 0% to 5%. At this time, the analog change rate can meet the requirement of making the analog value approach the target control value smoothly and relatively quickly. Therefore, the opening degree of the second regulating valve can be set to, for example, 5%, to maintain the current analog change rate as much as possible.

[0091] If the current analog value is in the negative buffer and the analog change rate BHL is greater than or equal to 0, then logic sequence 5 is executed to control the second regulating valve. The opening of the second regulating valve can be selected from 5% to 10%. At this time, the analog value is relatively close to the target control value, but the analog value decreases slowly. The opening of the second regulating valve can be increased to control the analog change rate within the range of (-0.05, 0).

[0092] If the current analog value is within the target control range and the analog change rate BHL is less than -0.1, then execute logic sequence 6 to control the opening of the second regulating valve to 0%. If the current analog value is already within the target control range, then the analog value and the target control value are very close. The difference between the two may be affected by the measurement accuracy. In this case, it is necessary to maintain the current analog value. Preferably, maintaining BHL within the range of [-0.1, 0.1] can be taken as the target. If BHL is greater than or equal to 0, then the second regulating valve needs to be closed in advance to slow down the downward trend of the analog value.

[0093] If the current analog value is within the target control range, the analog change rate BHL is within the range of [-0.1, 0.1], and the inflection point DD of the analog change trend is greater than 0, then logic sequence 7 is executed to control the second regulating valve. The opening degree of the second regulating valve can be selected from 3% to 5%. At this time, the trend of the analog value changes from decreasing to increasing, so it is necessary to increase the opening degree of the second regulating valve in advance to maintain the analog value within the target control range.

[0094] If the current analog value is within the target control zone, the analog change rate BHL is within the range of [-0.1, 0.1], and the inflection point DD of the analog change trend is less than 0, then execute logic sequence number 8 to control the opening of the second regulating valve to 0%. At this time, the trend of the analog value changes from rising to falling, so it is necessary to close the first regulating valve in advance to maintain the analog value within the target control zone.

[0095] If the current analog value is within the target control range and the analog change rate BHL is greater than or equal to 0.1, then execute logic sequence number 9 to control the second regulating valve. The opening degree of the second regulating valve can be selected from 5% to 10%. When BHL is greater than or equal to 0.1, the analog value decreases slowly and has an upward trend, so it is necessary to increase the opening degree of the second regulating valve in advance to keep the analog value within the target control range.

[0096] If the current analog value is in the negative buffer and the analog change rate BHL is less than or equal to -0.01, then execute logic sequence number 10 to close the second regulating valve and open the first regulating valve. The opening degree of the first regulating valve can be selected from 5% to 10%. At this time, the analog value drops into the negative buffer and the rate of drop is relatively fast, so the first regulating valve needs to be opened to increase the analog value.

[0097] If the current analog value is in the negative buffer, the analog change rate BHL is greater than -0.01, and the inflection point DD of the analog change trend is greater than 0, then execute logic sequence 11 to close the first and second regulating valves. At this time, the trend of the analog value changes from decreasing to increasing, allowing the analog regulating valves to be closed in advance.

[0098] If the current analog value is in the outer negative buffer and the inflection point DD of the analog value change trend is less than 0, then execute logic sequence number 12 to close the second regulating valve and open the first regulating valve. The opening degree of the first regulating valve can be selected from 10% to 20%. At this time, the trend of the analog value change from rising to falling, and the first regulating valve needs to be opened in advance.

[0099] If the current analog value is in the outer negative buffer and the inflection point DD of the analog value's change trend is greater than 0, then execute logic sequence number 13 to close the first and second regulating valves. At this time, the trend of the analog value changes from decreasing to increasing, allowing the first regulating valve to be closed earlier.

[0100] It is understood that the above settings for the analog quantity change rate BHL and the analog quantity regulating valve opening are merely examples, and those skilled in the art can flexibly set them according to actual needs.

[0101] See Figure 5 The figure is a schematic diagram of an analog quantity control device based on a distributed control system provided in an embodiment of this application. The device includes: an acquisition module 501, a determination module 502, and a control module 503.

[0102] The acquisition module 501 is used to acquire multiple analog quantity control intervals, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends.

[0103] The determining module 502 is used to determine the control rules of the analog quantity regulating valve based on the analog quantity value at time zero; the control rules of the analog quantity regulating valve include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening degree of the analog quantity regulating valve in different analog quantity control intervals.

[0104] The control module 503 is used to control the opening degree of the analog quantity regulating valve based on the control rules of the analog quantity regulating valve, the analog quantity control interval where the current analog quantity value is located, the rate of change of the analog quantity, and the inflection point of the trend of the analog quantity change.

[0105] Therefore, in this embodiment of the application, by dividing multiple analog quantity control intervals and configuring different analog quantity regulating valve openings for different combinations of analog quantity change rates and inflection points of analog quantity change trends within each analog quantity control interval, the adjustment requirements for analog quantity values ​​under different conditions can be met more accurately, thereby improving the control accuracy, control efficiency and control stability of analog quantities, and thus improving the stability of product quality.

[0106] See Figure 6 The figure is a controller structure diagram of a distributed control system provided in an embodiment of this application. The controller includes a memory 601 and a processor 602.

[0107] Memory 601: Used to store program code and transfer program code to the processor.

[0108] Processor 602: Used to execute the steps of the above-described analog control method based on a distributed control system according to the instructions in the program code.

[0109] In addition, this application also provides a computer-readable storage medium storing computer instructions, which, when executed on a controller applied to a distributed control system, cause the controller to perform the steps of the analog control method based on the distributed control system described above.

[0110] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the controller and storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The controller and storage medium embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0111] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An analog control method based on a distributed control system, characterized in that, The method includes: The system acquires multiple analog quantity control intervals, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends. The multiple analog quantity control intervals include: an outer positive buffer, a positive buffer, a target control region, a negative buffer, and an outer negative buffer. The minimum value of the outer positive buffer is greater than the maximum value of the positive buffer; the minimum value of the positive buffer is greater than the maximum value of the target control region; the minimum value of the target control region is greater than the maximum value of the negative buffer; and the minimum value of the negative buffer is greater than the maximum value of the outer negative buffer. Based on the analog quantity value at time zero, the control rules for the analog quantity regulating valve are determined. The control rules for the analog quantity regulating valve include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening of the analog quantity regulating valve within different analog quantity control intervals. Specifically, if the analog quantity value at time zero is less than the target control value, the control rule for the analog quantity regulating valve is determined as the first control rule. The target control value is the median value of the target control region. The opening degree of the analog quantity regulating valve is controlled based on the analog quantity regulating valve control rules, the analog quantity control range where the current analog quantity value is located, the analog quantity change rate, and the inflection point of the analog quantity change trend. The first control rule is: If the current analog value is in the outer negative buffer, the negative buffer, or the target control area, the opening of the first regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the first regulating valve is used to increase the analog value. If the current analog value is in the outer positive buffer or the positive buffer, the opening of the second regulating valve is controlled based on the analog control range where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the second regulating valve is used to reduce the analog value.

2. The method according to claim 1, characterized in that, The step of determining the analog quantity regulating valve control rule based on the analog quantity control range in which the analog quantity value lies and the analog quantity change rate further includes: If the analog value at time zero is greater than the target control value, then the analog regulating valve control rule is determined to be the second control rule.

3. The method according to claim 1, characterized in that, When the analog value at time zero is less than the target control value: If the current analog value is within the outer negative buffer zone, the opening degree of the first regulating valve is selected from 20% to 80%. If the current analog value is within the negative buffer zone or the target control zone, the opening degree of the first regulating valve is selected from 0% to 10%. If the current analog value is in the positive buffer or the outer positive buffer, then the first regulating valve is closed and the second regulating valve is opened, wherein the opening degree of the second regulating valve is selected from 0% to 20%.

4. The method according to claim 2, characterized in that, The second control rule is: If the current analog value is in the outer negative buffer or the negative buffer, the opening of the first regulating valve is controlled based on the analog control range where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value. If the current analog value is in the outer positive buffer zone, the positive buffer zone, or the target control zone, the opening of the second regulating valve is controlled based on the analog control zone where the current analog value is located, the analog change rate, and the inflection point of the analog change trend.

5. The method according to claim 4, characterized in that, When the analog value at time zero is greater than the target control value: If the current analog value is within the outer positive buffer zone, the opening degree of the second regulating valve is selected from 20% to 80%. If the current analog value is within the target control zone or the positive buffer zone, the opening degree of the second regulating valve is selected from 0% to 10%. If the current analog value is in the outer negative buffer or the negative buffer, then the second regulating valve is closed and the first regulating valve is opened, wherein the opening degree of the first regulating valve is selected from 0% to 20%.

6. An analog quantity control device based on a distributed control system, characterized in that, The device includes: an acquisition module, a determination module, and a control module; The acquisition module is used to acquire multiple analog quantity control intervals, analog quantity values, analog quantity change rates, and inflection points of analog quantity change trends; the multiple analog quantity control intervals include: an outer positive buffer, a positive buffer, a target control area, a negative buffer, and an outer negative buffer; the minimum value of the outer positive buffer is greater than the maximum value of the positive buffer; the minimum value of the positive buffer is greater than the maximum value of the target control area; the minimum value of the target control area is greater than the maximum value of the negative buffer; the minimum value of the negative buffer is greater than the maximum value of the outer negative buffer. The determining module is used to determine the control rules for the analog quantity regulating valve based on the analog quantity value at time zero. The control rules for the analog quantity regulating valve include the correspondence between the rate of change of the analog quantity and the inflection point of the trend of the analog quantity change and the opening of the analog quantity regulating valve within different analog quantity control intervals. Specifically, if the analog quantity value at time zero is less than the target control value, the control rule for the analog quantity regulating valve is determined to be the first control rule. The target control value is the median value of the target control region. The control module is used to control the opening degree of the analog quantity regulating valve based on the control rules of the analog quantity regulating valve, the analog quantity control interval where the current analog quantity value is located, the rate of change of the analog quantity, and the inflection point of the trend of the analog quantity change. The first control rule is: If the current analog value is in the outer negative buffer, the negative buffer, or the target control area, the opening of the first regulating valve is controlled based on the analog control interval where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the first regulating valve is used to increase the analog value. If the current analog value is in the outer positive buffer or the positive buffer, the opening of the second regulating valve is controlled based on the analog control range where the current analog value is located, the rate of change of the analog value, and the inflection point of the trend of the analog value; the second regulating valve is used to reduce the analog value.

7. A controller applied to a distributed control system, characterized in that, The controller includes: a memory and a processor; The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the steps of the analog quantity control method based on a distributed control system as described in any one of claims 1-5, according to the program code.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when run on a controller applied to a distributed control system, executes the steps of the analog control method based on a distributed control system as described in any one of claims 1-5.

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