LU504164B1 - Filter in DCS control system, control method and DCS control system - Google Patents

Abstract

A historical measured value is adopted to be compared with a measured value at the current moment to determine whether a sudden change occurs; if the sudden change is determined to occur, a switching mode is executed to replace the measured value with the historical measured value for output; after a certain period of time, the switching mode is recovered to a normal mode to output the measured value, So that that filter of the occasional fluctuation is realized, the filter effect is good, the influence of the measured mutation value is effectively eliminated, and a protection mechanism based on a measured value is still provide.

Description

Filter in DCS control system, control method and DCS control system"">%4%*

Technical field

The invention relates to the technical field of filters, in particular to a filter in a DCS control system, a control method and the DCS control system.

Background technology

In that exist distributed control system (DCS), the bus technology is use to transmit the measured values such as field pressure, flow and the like, but the disadvantage of the bus system is that the transmission is unstable, It has a great impact on the stable operation of the equipment and the automatic regulation of the system.

The existing filtering method for the measured mutation value cannot effectively eliminate the influence of the measured mutation value.

Summary of the invention

In order to solve the problem, the invention provides a filter in a DCS control system, which comprises a filter logic module, wherein the filter logic module comprises a first delay reading sub-module, a second delay reading sub-module, a switching sub-module, comparison sub-modules, a delay closing sub-module and a data output sub-module; The first time delay reading submodule is used for reading a first historical measurement value with a first preset time interval with the current time, and the second time delay reading submodule is used for reading a second historical measurement value with a second preset time interval with the current time; The comparison sub-module is used for judging whether the difference value between the first historical measured value and the measured value at the current moment is larger than a jumping threshold value, and triggering the switching sub-module to execute a switching mode under the condition that the difference value is larger than the jumping threshold value; In a normal mode, the switching sub-module is configured to send the measured value to the data output sub-module, and after being triggered to execute a switching mode, the switching sub-module is configured to send the second historical measured value to the data output sub-module; The delay closing submodule is used for triggering the switching submodule to execute the normal mode after the switching submodule executes the switching mode for a third preset duration; and the data output submodule is used for outputting the measured value or the second historical measured value.

Optionally, the comparison sub-module comprises a subtraction unit, an absolute value unit and a comparison unit, wherein the subtraction unit is used to calculate the difference between the measured value and the first historical measured value, and the absolute value unit is used to calculate the absolute value of the difference; And the comparison unit is used for comparing the absolute value with the hopping threshold, and triggering the switching sub-module to execute a switching mode under the/504164 condition that the absolute value is larger than the hopping threshold.

Optionally, the data input end of the filter is respectively connected with the first delay reading submodule, the second delay reading submodule, the comparison submodule and the switching submodule; The first delay reading submodule is connected with the switching submodule, and the switching submodule is connected with the data output submodule.

Optionally, the first preset duration is equal to the sampling period of the measured value.

Optionally, the second preset duration is greater than or equal to the first preset duration.

Optionally, the third preset duration is greater than the average duration of the jump duration.

The invention provides a method for controlling a filter in a DCS control system, which is characterized in that the method is applied to the filter and comprises the following steps of: acquiring a measured value at the current moment and a first historical measured value before a first preset duration of the current moment; judging whether the difference value between the measured value and the first historical measured value is greater than a jump threshold; and determining whether the jump threshold is greater than the first preset duration; If so, a switching mode is executed to output a second historical measurement value before a second preset duration of the current moment, and if not, a normal mode is executed to output a measured value of the current moment.

Optionally, the method further comprises re-executing the normal mode after the switching mode is executed for a third preset duration.

Optionally, the first preset duration is equal to the sampling period of the measured value, or the second preset duration is greater than or equal to the first preset duration, or the third preset duration is greater than the average duration of the jump.

In the embodiment of the invention, the historical measured value is compared with the measured value at the current moment to determine whether a sudden change occurs, a switching mode is executed to output the historical measured value instead of the measured value when the sudden change occurs, And still has a protection mechanism based on measured values.

Brief description of the drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, Other figures may also be derived from the figures provided.

Fig. 1 is a schematic diagram of the effect of reducing the influence of hopping by usingld/504164 delay module in the prior art;

Fig. 2 is a schematic structural diagram of a filtering logic module according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of the effect of a filtering logic module in reducing the influence of a jump according to an embodiment of the present invention;

Fig. 4 is a flowchart of a method for controlling a filter in a DCS control system according to an embodiment of the present invention.

Detailed description of the invention

So that the above objects, features and advantages of the present invention will become more apparent, a detailed description of specific embodiments of the present invention will be made with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the prior art, in order to eliminate the measurement dead points under the non-fault condition, a mode of adding a time delay module is usually adopted to reduce the jumping influence. Fig. 1 is a schematic diagram showing the effect of using a delay module to reduce the influence of hopping.

When the module is used, the lower curve is the actual analog signal, and the upper curve is the analog signal processed by the delay module. As shown in fig. 1, when the actual analog signal has a sudden change, that is, the sudden drop marked by a, B, C, d and e of the lower curve, there is also a small downward sudden drop at the corresponding position of the upper curve, that is, the image marked by 1, 2, 3, 4 and 5 of the upper curve. Therefore, the existing delay module has a certain effect, but it can not make the curve smooth, and the curve still has a small downward dip. Since the above sudden drop fluctuation still exists, the automatic regulation is affected, or the protection action is caused. The filter provided by the embodiment of the invention can smooth the curve, realize complete filtering and avoid disturbance.

The embodiment of the invention provides a filter in a DCS control system, which comprises a filtering logic module. The filter can be used in the occasional fluctuation measurement logic circuit with small actual fluctuation of the measured value, and is used for filtering the occasional fluctuation, and the filtering effect is good, and the measured data curve is smooth.

The filtering logic module comprises a first delay reading sub-module, a second delay reading sub-module, a switching sub-module, comparison sub-modules, a delay closing sub-module and a data output sub-module. LUS04164

The first time delay reading submodule is used for reading a first historical measurement value which is spaced from the current time by a first preset time length, and the second time delay reading submodule is used for reading a second historical measurement value which is spaced from the current time by a second preset time length. The filtering logic module can store the historical measurement value of the historical moment, and can also store the historical measurement value in other storage devices, and the filtering logic module can read it as required.

The comparison sub-module is used for judging whether the difference value between the first historical measured value and the measured value at the current moment is larger than a jumping threshold value, and triggering the switching sub-module to execute a switching mode under the condition that the difference value is larger than the jumping threshold value. The first historical measurement value corresponding to the historical time which is spaced from the current time by a first preset time length is used as a comparison basis for judging whether the actual measurement value of the current time has a jump. Since the embodiment is aimed at the measurement scene with small actual fluctuation of the measured value, there is no large jump under normal conditions, while the large jump may occur due to unstable transmission and other reasons, the jump threshold may be determined based on the fluctuation range of the measured value of the actual measurement scene, and the jump threshold is greater than the normal fluctuation range of the measured values and smaller than the jump range. O as to effectively distinguish whether the measured value jumps or not. The first preset duration may be a sampling period of one or more measured values to obtain the historical measured value of the historical moment. For example, the first preset duration is equal to the sampling period of the measured value.

The switching sub-module is used for executing a normal mode or a switching mode; and in the normal mode, the switching sub-module is used for sending the measured value to the data output sub-module, and after being triggered to execute the switching mode, the switching sub-modules are used for sending the second historical measured value to the data output sub-module. A historical time with an interval of a second preset duration from the current time, the second preset duration being greater than or equal to the first preset duration, and the historical measurement value of the historical time having no jump, replacing the measured value of the current time with the historical measurement value. Through the substitution of near values, the effective filtering is realized.

The delay closing submodule is used for triggering the switching submodule to execute the normal mode after the switching submodule executes the switching mode for a third preset/>04164 duration. Considering that the jump of the measurement value will last for a certain period of time, the switching sub-module needs to continuously execute the switching mode within the period of time, that is, output the second historical measurement value, and after the duration of 5 time, it needs to return to the normal mode of operation, so as to avoid the failure of the subsequent protection logic due to the substitution of a near value. Therefore, the third preset duration may be longer than the average duration of the transition duration, and should not be too long, so as to avoid the filtering effect of the transition value and reduce the protection delay in the case of an actual fault. It can be understood that the protection time delay is the second preset duration or the third preset duration, and specifically, the protection time delay can be the smaller duration of the second preset duration or the third preset duration.

The data output submodule is used for outputting a measured value or a second historical measured value.

According to the filter in the DCS control system provided by the embodiment of the invention, the historical measured value is compared with the measured value at the current moment to determine whether a sudden change occurs, a switching mode is executed under the condition that the sudden change is determined to occur, the historical measured value is output instead of the measured value, and after a certain period of time is continued, the filter returns to a normal mode to output the measured value, The filtering effect is good, the influence of the measurement mutation value is effectively eliminated, and the protection mechanism based on the measured value is still provided.

For example, the comparison sub-module comprises a subtraction unit, an absolute value unit and a comparison unit, wherein the subtraction unit is used for calculating the difference between the measured value and the first historical measured value, and the absolute value unit is used for calculating the absolute value of the difference; The comparing unit is used for comparing the absolute value with the jumping threshold value and triggering the switching sub-module to execute the switching mode under the condition that the absolute value is larger than the jumping threshold value.

In an example, the data input end of the filter is connected to the first delay reading sub-module, the second delay reading sub-module, the comparison sub-module and the switching sub-module respectively, and the measured values are input to the first delay reading sub-modules, the second delay reading submodules and the comparison sub-modules respectively. The first time delay reading sub-module, the comparison sub-module and the time delay closing sub-module are connected in sequence, and the time delay closing sub-module is connected with the switching sub-module; the first time delay reading sub-module is connected with the switching sub-module; and the switching submodule is connected to the data outpk}504164 sub-module.

Fig. 2 is a schematic structural diagram of a filtering logic module in an embodiment of the present invention. It is shown that the analog quantity values are respectively input into the first delay reading submodule, the second delay reading submodule, the comparison submodule and the switching submodule. The comparison submodule comprises a subtraction unit, an absolute value unit and a comparison unit which are sequentially connected, and the comparison unit is connected with the delay closing submodule. The delay closing submodule and the second delay reading submodule are both connected with the switching submodule.

In the embodiment of the invention, a new filtering logic module is established to replace the original delay module. The use condition of the new logic block is that under normal operation conditions, the simulation value fluctuates slightly, the historical curve is smooth, and there is no sudden decrease or increase.

Function of filtering logic module: it can eliminate the abnormal interference value in a short period of time, so that the measured value in this period of time is extremely close to the true value.

For example, the change range before and after the measured value is small, the fault time period is short (generally about 1 second), and the fault frequency is not high (the minimum fault interval is more than 10 minutes), so the measured value 3 - 5 seconds before the fault is taken to replace the measured value at the time of the fault, and there is basically no change.

The delay reading logic block reads the measured value of the analog quantity parameter to be filtered 3 seconds ago in real time and sends it to the analog quantity switching logic block.

The analog quantity switching logic block realizes the switching of the measured value or the measured value 3 seconds ago and sends it to the analog acquisition block. The switching condition is as follows: if the absolute value of the difference between the measured value and the measured value before one sampling period (usually the sampling period is 0.4 s or 0.8 s) is greater than a certain threshold, it is considered that the measured value has a jump fault, and then the switching condition is triggered to output the measurement value 3 s ago. Recovery after switching for 2 seconds (generally, the jump time is within 1 second, and 2 seconds can ensure to avoid the jump value).

In addition, the above design still maintains the protection mechanism of the equipment.

Once the equipment does fail and the measured value actually changes suddenly, the design will act after a delay of 3 - 5 seconds, which has little impact on the equipment.

The above duration and comparison values can be flexibly selected according to the actual working conditions and the nature of the sampling point. LUS04164

Fig. 3 is a schematic diagram showing the effect of the filtering logic module in reducing the influence of the jump in an embodiment of the present invention. The lower curve in fig. 3 is the actual analog signal, and the upper curve is the analog signal processed by the filter logic module. As shown in Figure 3, when the actual analog signal has a sudden change, that is, the sudden drop marked by a, B, C, d and e of the lower curve has no sudden change at the corresponding position of the upper curve. The processed numerical curve is smooth and the filtering effect is good, which does not affect the subsequent protection and calculation logic.

[0040] FIG. 4 is a schematic flow chart of a method for controlling a filter in a DCS control system according to an embodiment of the present invention, which is applied to the above filter, and the method comprises the following steps:

S402: Obtain a measured value at the current moment and a first historical measured value before a first preset duration of the current moment.

S404: Judge whether the difference between the measured value and the first historical measurement value is greater than the jump threshold, if so, execute S406; if not, execute S408.

S406: Perform a switching mode to output a second historical measurement value before a second preset duration of the current time.

S408, executing the normal mode to output the measured value at the current time.

Further, the method may further comprise the following step of re-executing the normal mode after the switching mode is executed for a third preset duration.

The control method for the filter in the DCS control system provided by the embodiment of the present invention is similar to the aforementioned control logic of the filter in the DCS control system, and is not described here again.

Of course, those skil in that art can understand that all or part of the processes for implement the method of the above embodiments can be implemented by a computer program instruct a control device, the program can be stored in a computer readable storage medium, and the execution of the program can include the processes of the above method embodiments, The storage medium may be a memory, a magnetic disk, an optical disk, or the like.

In this document, relational terms such as first and second and the like are used solely to distinguish one entity or operation from another entity or operation without necessarily requiring or implying any such actual relationship or order between such entities or operations. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further restriction, 4504164 the statement "including a." A defined element does not preclude the presence of another identical element in the process, method, article, or apparatus comprising the element.

In this specification, each embodiment 1s described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

The above description of the disclosed embodiments will enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

CLAIMS LU504164

1.A filter in a DCS control system, comprising a filtering logic module, wherein the filtering logic module comprises a first delay reading sub-module, a second delay reading sub-module, a switching sub-module and a comparison sub-module; the first time delay reading submodule is used for reading a first historical measurement value which has a first preset time interval with the current time; The second time delay reading submodule is used for reading a second historical measurement value of a second preset time interval with the current time; the comparison sub-module is configured to judge whether a difference between the first historical measured value and the measured value at the current moment is greater than a transition threshold, and trigger the switching sub-module to execute a switching mode if the difference is greater than the transition threshold; the switching sub-module is used for executing a normal mode or a switching mode, and in the normal mode, the switching sub-module is used for sending the measured value to the data output sub-module, and after being triggered to execute the switching mode, the switching sub-modules are used for sending the second historical measured value to the data output sub-module; the delay closing sub-module is used for triggering the switching sub-module to execute the normal mode after the switching sub-module executes the switching mode for a third preset duration; the data output submodule is configured to output the measured value or the second historical measured value.

2 The filter according to claim 1, wherein the comparison sub-module comprises a subtraction unit, an absolute value unit, and a comparison unit; the subtraction unit is configured to calculate a difference between the measured value and the first historical measured value; the absolute value unit is used for calculating the absolute value of the difference value; And the comparison unit is used for comparing the absolute value with the hopping threshold, and triggering the switching sub-module to execute a switching mode under the condition that the absolute value is larger than the hopping threshold.

3. The filter according to claim 1, wherein the data input end of the filter is respectively connected with the first delay reading submodule, the second delay reading submodule, the comparisoïr 904164 submodule and the switch submodule; the first delay reading submodule, the comparison submodule and the delay closing submodule are connected in sequence, and the delay closing submodule is connected with the switching submodule; the first delay reading submodule is connected with the switching submodule; and that switch submodule is connected with the data output submodule.

4 The filter of claim 1, wherein the first predetermined duration is equal to a sampling period of the measured value.

5.The filter of claim 1, wherein the second predetermined duration is greater than or equal to the first predetermined duration.

6.The filter of claim 1, wherein the third predetermined duration is greater than the average duration of the transition.

7. A method for controlling a filter in a DCS control system, applied to the filter according to claim 1, the method comprising: obtaining a measured value at the current moment and a first historical measured value before a first preset duration of the current moment; judging whether the difference between the measured value and the first historical measured value is greater than a jump threshold, if yes, executing a switching mode to output a second historical measurement value before a second preset duration of the current moment; if not, the normal mode is executed to output the measured value of the current moment.

8. The method of claim 7, wherein the method further comprises: and after the switching mode is executed for a third preset duration, executing the normal mode again.

9. The method according to claim 7, wherein the first predetermined duration is equal to a sampling period of the measured value, or the second predetermined duration is greater than or equal to the first predetermined duration, or the third predetermined duration is greater than an average duration of a jump.

10. ADCS control system comprising a filter according to claim 1.

: ; . . LU504164 the invention provides a filter in a DCS control system, a control method and the DCS control system.