JPH07210239A - Plant monitoring and controlling equipment - Google Patents

Abstract

PURPOSE:To estimate the occurrence of a fault and to previously take a measure to this fault by applying the prescribed arithmetic processing to the process data to calculate the specific value of a controlled object plant, calculating the trend value of change of the characteristic value, and comparing the trend value with the threshold value to decide a fault of the plant. CONSTITUTION:A characteristic value arithmetic unit 15 reads out the process data synchronously with the updating cycle of a process data base 14 and calculates the characteristice value based on the characteristic value calculating expression registered on a characteristic value definition table 16 to store the characteristic value in a characteristic value file 17. Then the timewisely changing trend of the specific value is calculated in a fixed cycle as the trend value and stored again in the file 17. A trend deciding device 20 compares the trend value with the trend decision standard registered in a management value table 19 to decide the trend. Thus the occurrence of a fault is estimated by the changing trend of the characteristic value so that a necessary measure is taken for improvement of the plant control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plant monitoring and controlling apparatus, and more particularly to a plant monitoring and controlling apparatus for performing digital control and monitoring of plant equipment to be controlled.

[0002]

2. Description of the Related Art Conventionally, a plant monitoring control device shown in FIG. 8 is known as a plant monitoring control device for performing digital control monitoring of controlled plant equipment. This conventional plant monitoring control device is used for various variables of the controlled plant equipment 1.
For example, temperature, pressure, flow rate, voltage, current, valve opening, etc. are converted into electrical quantity signals and collected by the process input / output device 2,
This is converted into engineering unit system data by the process data processing device 3 and stored in the process database 4.
On the other hand, in the alarm threshold value table 5, threshold values for judging abnormality of process data for each device are registered. Then, in the monitoring device 6, the process data for each device extracted from the process database 4 is compared with the alarm threshold value of the corresponding process registered in the alarm threshold value table 5, an abnormality determination is performed, and the output device A message notifying the abnormality is displayed on the CRT display device 7 and the necessary information is printed out by the printer 8.

[0003]

However, such a conventional plant monitoring and controlling apparatus has the following problems.

That is, in the conventional plant monitoring and controlling apparatus, only the abnormality is judged for each device, and it is inevitable to individually monitor the states of a plurality of devices in the state monitoring of the device. However, there is a problem that the operator's experience is unavoidable in order to control the plant in a stable direction, because it cannot only predict the trend of future changes automatically. there were.

Further, the alarm threshold values defined in the alarm threshold value table 5 are not strictly set, and are set to a soft value so that the experience in operation or the alarm frequency does not become extremely large. However, there is also a problem that it is not always reflected in the plant abnormality.

Further, in a plant composed of a plurality of devices, even if an abnormality occurs in a certain device, it may not be abnormal in the entire plant. However, in such a case, an alarm should be output immediately. Then, there is a problem that the alarm is output too frequently, which makes it difficult to operate.

The present invention has been made in view of the above conventional problems, and calculates a characteristic value indicating the characteristic of a plant to be controlled, further calculates a tendency of its temporal change, and calculates an alarm threshold value. It is an object of the present invention to provide a plant monitoring and control device that makes an abnormality determination by comparison and predicts the occurrence of an abnormality in advance so that necessary measures can be taken.

[0008]

According to a first aspect of the present invention, a plant monitoring control apparatus stores an input processing unit for inputting process data of various equipments of a plant to be controlled, and process data input from the input processing unit. A process data storage unit, a characteristic value calculation unit that obtains a characteristic value of a controlled plant by performing a predetermined calculation process on the process data stored in the process data storage unit, and a characteristic that the characteristic value calculation unit obtains. It is provided with a tendency value calculating section for calculating a tendency value change value and an abnormality determining section for comparing the tendency value obtained by the tendency value calculating section with a threshold value and making a plant abnormality determination.

According to a second aspect of the present invention, in the plant monitoring control apparatus according to the first aspect, a communication device for transmitting process data of various devices of a controlled plant to an input processing unit is provided.

According to a third aspect of the present invention, in the plant monitoring control apparatus according to the first aspect, the input processing unit and the process data storage unit are installed in the control room, and the characteristic value calculation unit, the tendency value calculation unit and the abnormality determination unit are provided. It is installed in a workstation and connected between them by LAN.

[0011]

According to the plant monitoring control apparatus of the invention of claim 1,
The input processing unit inputs process data of various devices of the controlled plant and stores the process data in the process data storage unit. Then, the characteristic value calculation unit obtains the characteristic value of the controlled plant by performing a predetermined calculation process on the process data stored in the process data storage unit, and the tendency value calculation unit further determines the tendency of the change of the characteristic value. The value is calculated, and the tendency value calculated by the tendency value calculating section in the abnormality judging section is compared with the threshold value to judge the abnormality of the plant.

In this way, by determining the abnormality of the plant to be controlled from the tendency of the change of the characteristic value of the process data, it is possible to predict the presence or absence of the abnormality from the tendency of the change of the characteristic value before the abnormality actually occurs. Be able to take necessary actions.

In the plant monitoring controller of the second aspect of the present invention, the process data of various devices of the controlled plant are transmitted to the plant monitoring controller located at a position away from the site by the communication device, and the characteristic value calculation and the trend value are performed there. Perform calculations and abnormality determination.

According to another aspect of the plant monitoring control apparatus of the present invention, the input processing unit and the process data storage unit are installed in the control room, and the characteristic value calculation unit, the tendency value calculation unit and the abnormality determination unit are installed in the workstation. By connecting them by LAN, each part is made independent and the degree of freedom of system construction is increased.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a circuit block diagram of an embodiment of the invention of claim 1, and a plant monitoring control apparatus of this embodiment is a process variable of various devices of a controlled plant 11, such as temperature, pressure, flow rate, current, voltage, A process input / output device 12 for inputting an on / off state of a switch as an electric quantity signal, and a process variable input to the process input / output device 12 for an engineering unit system, for example, ° C, kg / m2, A,
A process data processor 13 for converting digital process data such as V, and a process database 14 for registering the digital process data converted by the process data processor 13 are provided.

The plant monitoring control apparatus of this embodiment also includes a characteristic value calculation unit 15 for performing a predetermined characteristic value calculation process, which will be described later, based on the digital process data registered in the process data 14, and this characteristic value calculation unit. A characteristic value definition table 16 that stores the characteristic value calculation method used by the arithmetic unit 15, a characteristic value file 17 that stores the characteristic values calculated by the characteristic value arithmetic unit 15, and characteristic values stored in this characteristic value file 17. And a tendency value calculation device 18 for calculating a tendency value from temporal fluctuations at regular time intervals.
And a management value table 19 for registering a threshold value for determining whether there is an abnormality in the tendency value, and a tendency value calculated by the tendency value calculation device 18 by calling the threshold value registered in the management value table 19. A trend judging device 20 for comparing and judging whether or not there is an abnormality in the control target plant or predicting whether or not there is an abnormality, a CRT display device 21 for displaying the judgment result of this tendency judging device 20, and a printer 22 for printing out are provided. There is.

Next, the operation of the plant monitoring and controlling apparatus having the above configuration will be described. A process variable electric quantity signal is input to the process input / output device 12 from various devices of the controlled plant 11, and this electric quantity signal is converted into an engineering unit system digital process data by the process data processing device 13 and stored in the process database 14. It is sent and stored here in chronological order.

Then, the characteristic value calculation device 15 reads the process data in synchronization with the update cycle of the process database 14, and executes the characteristic value calculation based on the characteristic value calculation method registered in the characteristic value definition table 16. , And are stored in the characteristic value file 17 in time series.

The characteristic value definition table 16 defines and stores variables and calculation formulas of equipment necessary for chemical engineering calculation for calculating characteristic values. This characteristic value calculation method varies depending on the plant to be controlled. For example, if the characteristic value is for the distillation column 23 as shown in FIG. 4, the material balance is for the distillation column 23, and for the heat exchanger 24 as shown in FIG. With the characteristic value, the thermal efficiency can be increased.

When defining the calculation method of the material balance which is the characteristic value of the distillation column 23 of FIG. 4, the raw material inflow amount F is used as a variable.
i, product distilling amount Po, and canning amount O are used. Fi = Po + O (1) holds between these variables. Therefore, the ratio Q between the raw material inflow amount and the product distillate amount as the characteristic value is defined as follows, and this is calculated to obtain the characteristic value Q.

Q = Po / Fi (2) When defining the calculation method of the thermal efficiency η which is the characteristic value of the heat exchanger 24 of FIG. 5, the raw material inflow amount Fi, the raw material inflow temperature Ti, and the outlet temperature To are variables. , The steam amount Fs is used, and the raw material specific gravity, raw material specific heat, and steam latent heat are used as constants. The formula for the heat balance is: required heat quantity Qi = Fi * (To-Ti) * material specific gravity * raw material specific heat (3), and the steam heat quantity supplied to realize this is steam heat quantity Qo = Fs * steam latent heat … (4). Therefore, the thermal efficiency η which is a characteristic value is defined as thermal efficiency η = Qi / Qo (5), and this is calculated to obtain the characteristic value η.

In the tendency value calculating device 18, the tendency of the characteristic value with time is calculated as a tendency value in a constant cycle based on the flowchart shown in FIG. 2, and stored again in the characteristic value file 17. That is, the past characteristic value for the tendency value calculation time is input from the current time registered in the characteristic value file 17 (step S1), the characteristic value is regarded as a linear function of time, and the slope of the characteristic value is calculated by a linear approximation operation. Is stored in the tendency value storage area of the characteristic value file 17 (steps S2 and S3). The flowchart of FIG. 2 shows a case where the characteristic value is calculated in a 1-minute cycle and the tendency value is calculated in a 5-minute cycle.

When the tendency value is calculated in this way, the tendency judgment is executed by the tendency judgment device 20 by comparison with the tendency judgment standard registered in the management value table 19.

The procedure of this tendency determination will be described with reference to the flowchart of FIG. In this embodiment, there are two types of processing, that is, processing for performing threshold value judgment of the management reference value and characteristic value registered in the management value table 19 and prediction processing for predicting how the characteristic value will change from the tendency value in the future. The process of is executed. Then, first, a certain number of predetermined past number values calculated up to the current time, for example, five trend values are input from the characteristic value file 17 (step S1).
1) Calculate the average value of the input tendency values (step S
12). Then, the current characteristic value is corrected by the average value of the obtained tendency values to calculate the characteristic predicted value (step S13).

Subsequently, the characteristic predicted value is stored in the management value table 19
In comparison with the control reference value registered in, if the characteristic predicted value fluctuates greatly outside the reference value, it is predicted that an abnormality will occur in future plant fluctuations, and a predicted alarm message is displayed on the CRT display device. It is displayed on 21 and is also output to the printer 22 as needed (steps S14 and S15).

If the characteristic predicted value does not exceed the range of the management reference value in step S14, it is next determined whether or not there is an abnormality by comparing the current characteristic value itself with the management reference value. It is displayed on the CRT display device 21 and is also output to the printer 22 as required (steps S16 and S17).

For example, the characteristic value file 17 shown in FIG.
Then, assuming that the management standard upper limit value is 1.6 and the management standard lower limit value is 0.9, if the characteristic value average value at time 10:10 when the tendency value is 0.1 is 1.5, the characteristic prediction is performed. Value is 1.6
Since this becomes the management reference upper limit value of 1.6, a predictive alarm is output to alert the operator.

Thus, in the plant monitoring control apparatus of this embodiment, the characteristic value serving as an index for accurately instructing the characteristic of the variation of the controlled plant is calculated in real time based on various variables, and the time is calculated. The operator also grasps the change tendency, judges the sudden abnormality at the present time from the abnormality of the characteristic value, predicts the future abnormality occurrence from the change tendency of the characteristic value, and informs the operator by outputting an alarm message. Reduce the burden of abnormality monitoring of
In addition, it is possible to perform an operation to prevent the occurrence of an abnormality that is predicted to occur in the future and prevent the occurrence of the abnormality, thus enabling stable operation management of the plant.

The present invention is not limited to the above-mentioned embodiment, and in particular, since the characteristic values are variously different depending on the plant to be controlled, the optimum one is selected according to the plant to be controlled. . The tendency value calculation method is not limited to the approximation by the linear function of the characteristic value, but a quadratic approximation or another approximation method can be used.

Next, an embodiment of the invention of claim 2 will be described with reference to FIG. In the plant monitoring controller of this embodiment, the process input / output device 12 and the process data processing device with communication function 13a described above are both installed at the site where the control target plant 11 is installed, and the process data processing device with communication function is also the same. 13b and each of the process database 14 to the printer 22 are installed in a control room at a position away from the site, and the process data processing device 13 is provided via a communication line 25 such as RS232C.
Digital process data is transmitted between a and 13b and registered in the process database 14.

In the case of this embodiment, each of the process database 14 to the printer 22, which is a part for accumulating process data and executing complicated arithmetic processing, is incorporated in a computer system as software, and vibration, pollution, etc. The computer system can be configured to be installed in a control room or the like, which is away from the site where the environmental conditions are severe, and the system abnormality and failure are less likely to occur, and the reliability of the system can be improved.

Next, regarding the embodiment of the invention of claim 3,
It will be described with reference to FIG. In the process management control device of this embodiment, a process data processing device 13, a process database 14, a CRT device 21 as a man-machine interface and a printer 22 are provided in a control room 2.
6, the characteristic value calculation device 15, the characteristic value definition table 16, the characteristic value file 17, the tendency value calculation device 18, the management table 19, and the tendency determination device 20 are incorporated in the workstation 27, and these control rooms 26 and The system configuration is characterized in that the workstations 27 are connected by a LAN 28. In addition, here, the characteristic value calculation device 15, the characteristic value definition table 16, the characteristic value file 1
7. The tendency value calculation device 18, the management table 19, and the tendency determination device 20 are all registered as software and are functions that are executed by the computer of the workstation 27, but are drawn by functional blocks for the sake of clarity. is there.

According to this system configuration, by changing the software registered in the workstation 27, it is possible to construct a general-purpose system that can be applied to various plants, and the system can be easily changed and maintained. . In addition, the accumulated process data can be freely used for other purposes.

[0034]

As described above, according to the invention of claim 1,
Input the process data of various equipment of the controlled plant by the input processing unit, store it in the process data storage unit,
The characteristic value calculation unit obtains the characteristic value of the control target plant by performing a predetermined calculation process on the process data stored in the process data storage unit, and the tendency value calculation unit further determines the tendency value of the change of the characteristic value. Is calculated, and the tendency value calculated by the tendency value calculation section in the abnormality determination section is compared with the threshold value to determine the abnormality of the plant. It is possible to predict the occurrence of an abnormality from the tendency, take necessary measures, and enhance the stability of plant control.

According to the second aspect of the present invention, since the process data of various devices of the controlled plant are transmitted to the plant monitoring control device at a remote position by the communication device, the process data is accumulated and complicated. Since it is not necessary to install a part for executing arithmetic processing in a site where environmental conditions such as vibration and pollution are severe, abnormalities and failures of the system are less likely to occur and reliability of the system can be improved.

According to the third aspect of the present invention, the input processing unit and the process data storage unit are installed in the control room, and the characteristic value operation unit, the tendency value operation unit and the abnormality determination unit are installed in the workstation, respectively. Since LANs are connected to each other by a LAN, a general-purpose system capable of supporting various plants can be constructed by changing the software registered in the workstation, and the system can be easily changed and maintained. In addition, the accumulated process data can be freely used for other purposes.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment of the invention of claim 1;

FIG. 2 is a flowchart showing a calculation processing function of the tendency value calculation device in the above embodiment.

FIG. 3 is a flowchart showing a tendency determination processing function of the tendency determination device in the above embodiment.

FIG. 4 is a systematic diagram of a distillation column to which the above example is applied.

FIG. 5 is a system diagram of a heat exchanger to which the above embodiment is applied.

FIG. 6 is a functional block diagram of an embodiment of the invention of claim 2;

FIG. 7 is a functional block diagram of an embodiment of the invention of claim 3;

FIG. 8 is a functional block diagram of a conventional example.

[Explanation of symbols]

 11 Control Target Plant 12 Process Input / Output Device 13 Process Data Processing Device 13a, 13b Process Data Processing Device 14 Process Database 15 Characteristic Value Calculation Device 16 Characteristic Value Definition Table 17 Characteristic Value File 18 Trend Value Calculation Device 19 Management Value Table 20 Trend Judgment Device 21 CRT display device 22 Printer 23 Distillation tower 24 Heat exchanger 25 Communication line 26 Control room 27 Workstation 28 LAN

Claims (3)

[Claims] 1. An input processing unit for inputting process data of various devices of a controlled plant, a process data storage unit for storing process data input from the input processing unit, and a process data storage unit for storing process data. A characteristic value calculation unit that obtains a characteristic value of the controlled plant by performing a predetermined calculation process on existing process data, and a tendency value calculation unit that calculates a tendency value of a change in the characteristic value obtained by the characteristic value calculation unit. Section, comparing the tendency value obtained by the tendency value calculation section with a threshold value,
A plant monitoring and control apparatus comprising: an abnormality determination unit that determines an abnormality of a plant. 2. The plant monitoring control apparatus according to claim 1, further comprising a communication device that transmits process data of various devices of the controlled plant to the input processing unit. 3. The input processing unit and the process data storage unit are installed in a control room, and the characteristic value calculation unit, the tendency value calculation unit and the abnormality determination unit are installed in a workstation, and they are connected by a LAN. The plant monitoring control apparatus according to claim 1, wherein