JPH02199600A - Trend graph display device - Google Patents

Abstract

PURPOSE:To automatically confirm the operating state of a plant by selecting a corresponding monitoring process item when abnormality or the change of an operating state is generated in an objective plant, collecting process values and automatically displaying the collected data on a trend graph. CONSTITUTION:A signal S3 indicating the operating state of each part of the plant is successively fetched into a selection means 2. Knowledge for deciding the operating state of the plant 1 based upon the signal S3 is stored in a knowledge base 3. The means 2 checks the operating state of the plant 1 based upon the signal S3 and the knowledge stored in the base 3. When any one of the parts of the plant 1 generates abnormality or the change of the operating state and necessity for monitoring the operation state of the process item is judged, the process item is selected. A signal S4 for defining the process item is outputted to a data collecting/storing means 4. The means 4 extracts a signal S5 indicating the operating state of the process item defined by the signal S4 from the plant 1, stores the signal and then displays the stored contents on a display means 5 as a trend graph.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a display device that displays the history of process values such as pressure, temperature, and flow rate for each process item in a target plant as a trend graph, and in particular, Depending on the situation, the process items that need to be monitored at any given time are automatically selected, the process values of the process items are periodically collected and stored, and the trend graphs of the process items are created automatically or according to instructions from the operator. The present invention relates to a trend graph display device that displays a trend graph.

(Prior art) In the display device of the prior art that displays the history of syrocess values as a trend graph, for example, as described in Japanese Patent Publication No. 6226469, a process in which a trend graph is to be displayed when an abnormality etc. occurs later in the target plant is used. The items are either fixedly registered in advance or are registered in advance by the operator operating appropriate means such as a manual input device.

In such a display device, when an abnormality occurs in the target plant, the operator selects the most suitable process item from among the previously registered process items to display as a trend graph in order to analyze the cause of the abnormality. , the process values near the current time and in the past of the selected process item are displayed as a trend graph.

In addition, if the operator wants to display a trend graph of a process item that has not been registered in advance, if the operator registers the process item that he or she wants to display using an appropriate means, the trend graph of the process item from that point will be displayed. Display starts.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, when an accident, abnormality, etc. occurs in the target plant, an operator can quickly select the optimal process item to display a trend graph for cause analysis. Since the operator had to make a selection, there was a problem in that the operator was required to be skilled and the burden on the operator was heavy.

In addition, in the conventional technology, since the process items targeted for trend graph display are registered in advance, even if the operator tries to select the optimal process item for abnormality cause analysis, or the target plant at that time Even if you try to display a trend graph of a process item that is most suitable for monitoring the operating status of the system, the process item is not always registered as a target item for trend graph display, and the trend graph display that is required at that time may not be obtained. There was a problem.

Furthermore, when an operator registers a process item to be displayed in a trend graph in advance, the process item and the display update cycle, display width, storage cycle, and display start time necessary for displaying the trend graph are registered in advance. The operator also had to specify various data such as end time and display range each time.

Therefore, there is a problem in that the operator is required to be skilled in registering process items to be displayed in a trend graph.

The purpose of the present invention is to solve the above-mentioned problems and, when an abnormality occurs in the target plant or when there is some change in the operating status of the target plant, to respond to the abnormal situation or change situation. To provide a trend graph display device that can automatically select a process item that requires monitoring, automatically collect process values of the process item, and display this as a trend graph. .

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides means for selecting process items to be observed according to the operating state of each part of a target plant, and a method for selecting process items to be observed. The feature is that it includes means for collecting process values of items and displaying trend graphs thereof.

(Function) According to the above configuration, if an abnormality occurs in the target plant or if there is any change in the operating status of the target plant, depending on the abnormality or change,
Process items to be observed are automatically selected, and
Process values for the process item are automatically collected and the results are displayed as a trend graph.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration of the present invention.

In the figure, a signal S3 indicating the operating state of each part of the plant 1 is sequentially taken in by the selection means 2.

The knowledge base 3 contains information about the plant 1 based on the signal S3.
Knowledge for determining the operating state of the plant 1 is stored, and the selection means 2 checks the operating state of the plant 1 based on the signal S3 and the knowledge stored in the knowledge base 3. 1, selects that process item and outputs a signal S4 defining the process item to the data collection/storage means 4. do.

The data collection/storage means 4 sequentially captures and stores signals S5 indicating the operating states of the process items defined by the signals S4 from the plant 1, and displays the values of the signals S5 in a trend graph as needed. Displayed on 5.

FIG. 2 is a block diagram showing the configuration of the main parts of a trend graph display device according to an embodiment of the present invention.

In the same figure, the actual data of each process item in the plant 8, such as the pressure and temperature of the boiler, and the displacement amount indicating the displacement state of the operating part in the plant 8, such as the opening degree of the on-off valve, are shown in the plant s. The sensor inside (
(not shown) is detected as a process value.

The process value input device 9 sequentially captures various process values detected by the sensor and temporarily stores them.

On the other hand, a control computer 7 that is installed in the plant 8 and controls various operations of the plant sends signals indicating the operating status of devices such as auxiliary equipment that make up the plant 8, as well as the operating results and operating hours of the plant 8. , various signals indicating the operating state and the like are output as the operation control signal S2.

As will be described in detail later, the factor detection means 1O detects factors AI, A2, . An is sequentially scanned and a factor that satisfies the process value S1 or operation control signal S2 at that time is detected.

As will be described in detail later, the factors registered as the assumed conditions are conditions under which it is determined that the target plant is not in a normal state based on the process value S1 and the operation control signal S2, or conditions that are related to the operating status of the target plant. This is a condition under which it should be determined that some kind of change has occurred.

The factor detection means 10 detects that the input process value S1 or operation control signal $2 is detected by the factor/item correspondence storage means 1.
If any of the factors registered in item 6 are satisfied, it is determined that an abnormality has occurred in the target plant or that some change has occurred in the operating status of the target plant, and appropriate measures will be taken to take appropriate action. The trend collection item selection means 11 is informed that the process values of the attached process items need to be collected as trend data.

Here, factor detection means 10, factor/item correspondence storage means 1
6 and the trend collection item selection means 11, and their respective operations will be explained in more detail.

The factor/item correspondence storage means 16 stores knowledge acquired through the past experience of the expert, for example, which process item should be monitored when the process value of a certain process item in the target plant exceeds the standard value. If you have the knowledge to track down the cause of the problem,
A large number of hen... models are registered.

Then, the assumption conditions AI below If, A2...An(
If the trend data collection factors (hereinafter referred to as trend data collection factors) are satisfied, then the process items Pi, P2 defined below
...Display the process values of Pn (hereinafter referred to as trend data collection items) in a trend graph.

The trend data collection factors (If...) include the following, and these factors will be explained here along with the trend data collection items associated with them.

(1) If the process value exceeds the alarm limit value, i.e.
This is a case where an analog process value indicating pressure, temperature, etc. of a boiler, etc. exceeds a preset alarm limit value and an alarm is issued. Therefore, the process item that is considered to be the cause of the process value exceeding the alarm limit value becomes the trend data collection item.

Specifically, the knowledge is ``If the pressure of boiler A is 10 atm or more, the opening degree of on-off valve A should be a trend button collection item.''
The above factors are the trend data collection factors, and the "opening degree of the on-off valve A" is the trend data collection item associated with the factors.

(2) When the process value tends to approach the alarm limit value (3) When the rate of change or amount of change in the process value is large (4) When an alarm occurs, that is, when analog action is not performed, for example, the contact status of a switch, etc. This is a case where the switch is not in the expected state and an abnormal alarm is generated to notify it.In such a case, in order to prevent an accident from occurring, the contact of the switch should be set to an unscheduled state. The process items that are thought to be the cause of the problem become the trend data collection items.

Specifically, it is knowledge such as "If contact X is closed, make the main steam temperature the trend data collection item," and "contact "Main steam temperature" is the trend data collection item.

(5) When the status of the main equipment of the plant changes, as detailed later in Figure 6, the opening of the on-off valve changes, or the main equipment stops operating and the auxiliary equipment starts operating. In such a case, in order to check the operating status, process items that are affected by the opening degree of the on-off valve or the operation of the auxiliary equipment become trend data collection items.

(6) When each part starts operating according to automation, that is, when the equipment in the plant automatically starts operating according to a predetermined program. In such a case, check the operating status. The process items necessary to do so become trend data collection items.

(7) When the regular safety test is carried out or when the scheduled time for the test has been reached As will be explained in detail with reference to FIG. In such a case, a double confirmation signal indicating that the regular safety test is to be carried out is output from one control computer 7 in the plant, and the process item resulting from the test becomes the trend data collection item.

(8) When the specified time is reached This is a case where the operating status of a device that operates at a designated time every day is checked, and in such a case, the process items necessary to check the operating status are This is a trend data collection item.

(9) When a certain period of time has passed after the state of the main equipment of the plant has changed.Although it is almost the same as that explained in relation to (5) above,
This is a case where it is not immediately determined that the state has changed even after the state has changed, but it is determined that the state of the main equipment has changed only when the state change continues for more than a scheduled time. The affected process items become trend data collection items.

The factor detection means 10 detects the process value S1 stored in the process value input device 9 and the control convenience store.
- From the operation control signal S2 output from evening 7,
The factor (1) registered in the factor/item correspondence storage means 16
) to (9) are detected, and if there is a detected factor, this is notified to the trend collection item selection means 11.

For example, the pressure of the boiler A can be input to the process value input device 9.
If the value is called from , it is determined whether the value is a normal value or not based on the above knowledge.

That is, it is determined whether the pressure of boiler A is 10 atm or more, and if it is 1Qatm or more, the trend collection item selection means 11 is notified that the pressure of boiler A is beyond the permissible range.

The trend collection item selection means 11 calls out items to be collected as trend data from the factor/item correspondence storage means 16 based on the information regarding the pressure of the boiler A,
The item is stored in the trend data collection item storage means 17. That is, the "opening degree of on-off valve A" is stored as the trend data collection item Pi.

Note that the number of trend data collection items stored in the storage means 17 is not limited to one, and a signal that satisfies the factors registered in the factor/item correspondence storage means 16 is detected by the factor detection means 10.
If other factors are detected, the process items stored in the factor/item correspondence storage means 16 corresponding to the factors are similarly stored as trend data collection items Pj...Pk in the trend data collection item storage means. 17.

In this way, the trend data collection items are stored in the storage means 17.
When stored, the trend data collection means 12 reads the process values of the trend data collection items stored in the storage means 17 from the process value input device 9, and periodically collects the process values as trend data. Remember.

The trend graph display means 13 converts the trend data into screen information according to a scheduled display format, and outputs the screen information to the display device 20 in real time.

At this time, data regarding the display update cycle, display width, etc. of each process value necessary when converting trend data into screen information is stored in the factor/item correspondence storage means 16 together with each factor and the process item associated with it. When the process item is transmitted to the trend data collection item storage means 17, the trend data collection means 12, etc., it is transmitted along with the process item.

Therefore, the display update period, display width, etc. of the trend data are automatically determined once the trend data collection items are determined.

In the above embodiment, when the process value 81 or the like satisfies any of the trend data collection factors, a signal indicating this is output from the factor detection means 10 to the trend collection item selection means 11. However, the present invention is not limited to this, and when a certain factor is detected by the factor detection means 10, the process item associated with the factor is automatically selected as a trend collection item. It may also be output to the means 11.

Furthermore, the trend collection item selection means 11 is not provided,
The trend data collection items detected by the factor detection means 10 and associated with the factors may be directly transmitted to the trend data collection item storage means 17.

In addition, in the above explanation, only the method of selecting and storing trend data collection items was explained, but after the trend data is stored and displayed as described above,
If the situation of the target plant satisfies the following factors also stored in the factor/item correspondence storage means 16 and is detected by the factor detection means 10,
Process items that satisfy the factors are not registered as trend data collection items.

That is, the display of trend data is also deleted when the situation of the target plant satisfies the following factors.

(10) When the process value returns to within the alarm limit value (1
1) When the tendency of the process value to approach the alarm limit value is resolved (12) When the rate or amount of change in the process value becomes small (18) When the alarm is restored (14) When the status of the main equipment of the plant changes (15) When the operation of each part according to automation has finished (16) When the regular safety test has finished (17) When the scheduled processing has finished after reaching the specified time (18) When the main parts of the plant have finished operating (19) When a certain period of time has elapsed after the start of data collection. As described above, according to the present invention, if there is an abnormality in the target plant. If an abnormality occurs or if there is any change in the operating status of the target plant, the process item that requires monitoring is automatically selected according to the abnormal situation or change situation, and the process item is Process values are automatically collected and automatically displayed as a trend graph, making it possible to check the operating status of the plant without any operator intervention.

FIG. 3 is a block diagram of another embodiment of the present invention;
The same reference numerals as in the figures represent the same or equivalent parts.

In this embodiment, the factor/item change means 14 is connected to the cause/item correspondence storage means 16, and the item change means 15 is connected to the trend data collection item storage means 17. The feature is that the contents can be changed freely by the operator.

In the figure, when changing, deleting, or adding knowledge in the form of If..., then... stored in the cause/mouth correspondence storage means 16, the operator operates the manual input device 21. , the factor/item changing means 14 changes the storage contents of the storage means 16 in accordance with the operation.

For example, regarding the pressure of boiler A, the knowledge was initially registered that ``If the pressure of boiler A is 10 atm or more, the opening of on-off valve A should be a trend data collection item,'' but from subsequent experience, If it becomes clear that when the pressure of boiler A becomes high, checking the opening degrees of on-off valves A and B will enable a more accurate grasp of the situation, the above knowledge can be used as a "boiler The pressure at A is lQa
If it is greater than or equal to tm, the opening degree of on-off valves A and B should be made a trend data collection item.

In this way, the factor/item correspondence storage means 16 has the following information:
Simple operations ensure that the latest knowledge is always stored, allowing more accurate decisions to be made.

Also, when changing the trend data collection items stored in the trend data collection item storage means 17, when the operator operates the manual input device 21, the item change means 1
5 analyzes the content of the operation and changes the content stored in the storage means 17.

In this way, the change state of any process item can be stored and displayed as trend data, regardless of whether it has been detected by the factor/item correspondence storage means 16, so it is possible to simply operate the plant. Even when it is desired to grasp a situation, a trend graph of related process items can be displayed, expanding the scope of use of the display device.

Note that the trend data collection items stored in the trend data collection item storage means 17 can also be changed, deleted, and added by the method described below.

Generally, in a trend graph display device built into a plant monitoring device, when the target plant is operating normally, a plant system diagram, alarm message, fault tree, etc. are displayed on the display device 26. has been done.

In this embodiment, even in such a case, the display device 2
By adding a touch panel mechanism to 6 and allowing the item changing means 15 to analyze touch panel operations performed by the operator, any process item can be registered in the storage means 17 as a trend data collection item.

Note that there are the following methods for picking trend data collection items on each screen display.

(a) Pick the numerical display area on the system graphic screen (b) Pick a specific symbol on the system graphic screen (C) Pick the alarm message on the alarm message screen (d) Event name on the fault tree display screen With this configuration, it becomes possible to more easily display a trend graph of any process item.

Note that the manual operation device 21 and the touch panel 22
can also be used to erase trend graphs already displayed on the screen.

That is, in the above embodiment, the trend graph already displayed on the screen is determined by the process item that caused the trend graph to be displayed due to the factor (lO).
Although the description has been made assuming that the trend graph of any process item is automatically deleted when any of the conditions (19) to You may also do this.

FIG. 4 shows that the trend graph display is started due to the factor (2), that is, it is determined that the process value of a certain process item is approaching the alarm limit value, and then the trend graph display is started due to the factor (11), that is, the process value of a certain process item is determined to be approaching the alarm limit value. This is a diagram for explaining the trend graph display method when the trend graph display ends when the tendency of the process value to approach the alarm limit value is resolved, where the horizontal axis represents time t and the vertical axis represents the process value Px. ing.

Below, in order to simplify the explanation, the inlet pressure of the boiler A will be explained as a process value Px.

FIG. 3(a) is a diagram showing the relationship between the inlet pressure Px of the boiler A input to the process value input device 9 and the time t, and the inlet pressure PX continues to rise gradually and the alarm limit value P
It shows how the limit value PH approaches I(, exceeds the limit value PH, and then falls below the limit value PH again.

When the inlet pressure Px of the boiler A changes in this way, when the inlet pressure PX exceeds (limit value PH-α) at time ta, the factor detection means 10 stores it in the factor/item correspondence storage means 16. For example, based on the knowledge that ``If the inlet pressure of boiler A tends to approach the limit value PI, make the outlet temperature of boiler A a trend data collection item,'' the ``inlet pressure of boiler A'' satisfies the above factors. It is determined that "boiler A outlet temperature" is selected as a trend data collection item in the trend data collection item storage means 17.
is memorized.

The trend data collection means 12 includes a process value input device 9
After that, the outlet temperature PS of boiler A is taken in from the second
As explained in the figure or FIG. 3, the outlet temperature P≦ is displayed one by one on the display device 26, and a trend graph as shown in FIG. 3(b) is obtained.

Further, the inlet pressure PX continues to decrease thereafter, and at time tb
When the value becomes less than or equal to (limit value PH-β), the factor detection means 10 stores in the factor/item correspondence storage means 16, for example, ``If the tendency of the inlet pressure of boiler A to approach the limit value PH has been resolved. For example, it is determined that the "inlet pressure of boiler A" satisfies the above factors based on the knowledge that "the outlet temperature of boiler A is determined from the trend data collection items", and the "outlet temperature of boiler A" is determined from the trend data collection items. The information is stored from the storage means 17.

Therefore, at time tb, the trend graph regarding the outlet temperature of boiler A is erased from the display screen.

In the above-mentioned embodiment, the process item for selecting the trend data collection item, that is, the above (1)
) to (9) are explained as being different from the process items displayed in the trend graph, but depending on the knowledge stored in the factor/item correspondence storage means 16, As shown, it is possible that both are the same.

The contents shown in FIG. 5 can be easily understood from the explanation regarding FIG. 4, so the explanation thereof will be omitted.

According to such a configuration, when a certain process item shows an abnormality sign, a trend graph of the process value of the process item or the process value of the process item associated with the process item is automatically displayed immediately. Therefore, the operator can immediately monitor the situation.

In addition, after the trend graph is displayed, the process item that caused the trend graph to be displayed is
) to (19), the trend graph display is automatically deleted, further reducing the burden on the operator.

Figure 6(a) shows an example where the trend display is started due to the above factor (5), that is, a change in the status of the main equipment of the plant, where the horizontal axis is time and the vertical axis is the process value. represents the condenser vacuum degree.

In addition, FIG. 6B shows the contents of the trend data collection start factor and collection end factor that are stored in the factor/item correspondence storage means 16 and are satisfied in this embodiment, the trend data collection items associated with the factors, At this time, the process items (
The contents of the trend data collection items) are shown in mock form.

In the startup process of a thermal power plant, etc., when raising the vacuum of a condenser, it is necessary to monitor whether the degree of vacuum is rising normally. Therefore, the contact state of the vacuum breaker valve is monitored by appropriate means, and the process value is input to the process value input device 9.

If the vacuum breaker valve changes from other than fully open to fully open, that is, if the starting factors shown in Figure (b) are satisfied, the process item "condenser vacuum level" or the trend data collection item is displayed. The information is stored in the collection item storage means 17, and thereafter, a trend graph display of the condenser vacuum degree is started.

Thereafter, once the degree of vacuum increases and the vacuum increase is completed, there is no need to monitor the degree of vacuum unless abnormal signs of a decrease in the degree of vacuum appear. Therefore, if a certain period of time (TD) has passed after the completion of the vacuum raising mask (a series of operations to raise the degree of vacuum to the expected value), that is, the termination factors shown in Figure (b) are satisfied. If so, “condenser vacuum level”
is no longer registered as a trend data collection item, and the trend graph display of condenser vacuum level is deleted.

As a result, the operator can automatically monitor the behavior of the degree of vacuum from the start of vacuum rise to the completion of vacuum rise.

FIG. 7(a) shows a trend graph display of the main valve opening degree when the main valve opening/closing test, which is one of the regular safety tests, is carried out based on the factor (7). Also,
FIG. 4B shows the contents of the trend data collection start factor and collection end factor that are stored in the factor/item correspondence storage means 16 and are satisfied in this embodiment, the trend data collection items associated with the factors, and The contents of the process items stored in the trend data collection item storage means 17 at this time are shown in a simulated manner.

When conducting an opening/closing test of the main valve, it is necessary to monitor not only whether the main valve simply opens and closes, but also whether the main valve opens and closes smoothly.

Therefore, in this embodiment, if the opening/closing test of the main valve is performed, the factor/item correspondence storage means 16 stores knowledge that the opening degree of the main valve is to be registered as a trend data collection item from a certain time tl before the opening/closing test of the main valve. be memorized in advance.

In this way, the control computer 7 outputs the operation control signal S2 to the factor detection means 10 for opening and closing the main valve a certain period of time tl before the test start time.
At the same time, the main valve opening trend graph display starts, and then, when the valve test starts at time ts,
Even if the valve test ends at time te, the display continues until a certain period of time t2 after the end time te of the test, as shown in FIG.

As a result, operators will be able to automatically monitor the behavior of the main valve opening during valve tests, and
It becomes possible to automatically obtain data for determining whether or not the operation of the main valve is normal.

In addition, in the above-mentioned example, the above-mentioned factor (2),
Although only (5) and (7) have been explained, since the case of other factors will be understood by the customer, their explanation will be omitted.

By the way, in the above-mentioned embodiments, in any case, all the trend data stored in the trend data collection means 12 starts to be displayed at the same time as the trend data is collected, and thereafter, the trend data display of process values progresses in real time. Although the present invention is not limited to this, even if a certain process item is registered as a trend data collection item in the trend data collection item storage means 17, the trend graph display cannot be started immediately. The data collection and storage in the trend data collection means 12 are performed without any data collection, and the operator operates the manual input device 21 or the touch panel 22 described with reference to FIG. Trend data already stored in the trend data collection means 12 may be displayed on the display device at once.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) If an abnormality occurs in the target plant or if there is any change in the operating status of the target plant, process items that require monitoring will be automatically determined according to the abnormality or change. Once selected, the process values for the process item are automatically collected and automatically displayed in a trend graph, making it possible to check the operating status of the plant without any operator intervention. .

(2) The contents of the cause/item correspondence storage means can be changed freely and easily by the operator, so the latest knowledge is always stored through simple operations, making it easier to monitor the operating status of the plant. It will be done more accurately.

(8) The storage contents of the trend data collection item storage means,
Since the operator can freely and easily make changes, changes in any process item can be stored and displayed as trend data. Therefore, even when it is simply desired to understand the operating status of a plant, a trend graph of related process items can be displayed, expanding the scope of use of the apparatus.

(4) Data regarding the display update cycle, display width, etc. of each process value required when converting trend data into screen information is as follows:
Once the trend data collection items are determined, they are automatically determined, reducing the burden on the operator.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention. FIG. 2 is a block diagram showing the configuration of the main parts of a trend graph display device according to an embodiment of the present invention. FIG. 3 is a block diagram of another embodiment of the invention. FIG. 4.5.6.7 is a diagram for explaining the trend graph display method.

Claims (11)

[Claims] (1) Equipped with a means for selecting a process item to be observed according to the operating state of each part of the target plant, and a means for collecting process values of the selected process item and displaying a trend graph thereof. A trend graph display device featuring: (2) A knowledge base is further provided in which process items to be observed based on the judgment result of the operation state of the target plant are stored, and the selection of the process item is based on the knowledge stored in the knowledge base. The trend graph display device according to claim 1, characterized in that the trend graph display device is operated based on the trend graph display device. (3) A process value input device for inputting and temporarily storing process values for each process item of the target plant, trend data collection factors for each signal indicating the operating status of each part of the target plant, and the factors. Trend data collection items, which are process items that should be observed when the above is satisfied, are considered as a pair of knowledge, a knowledge base in which a plurality of the pair of knowledge is registered, and any trend data collection factor registered in the knowledge base. factor detection means for detecting a factor that satisfies either the process value input to the process value input device and the operation control signal output from the target plant and controlling the operation of the target plant; trend data collection item storage means for storing trend data collection items paired with detected trend data collection factors; and collecting process values of the stored trend data collection items from the process value input device at scheduled intervals. What is claimed is: 1. A trend graph display device comprising: a trend data collection means for storing trend data; and means for displaying the trend data stored in the trend data collection means as a trend graph. (4) further comprising trend collection item selection means for selecting a trend data collection item paired with the detected trend data collection factor from the knowledge base;
4. The trend graph display device according to claim 3, wherein said trend data collection item storage means stores said selected trend data collection item. (5) The pair of knowledge includes a trend data collection factor, a trend data collection item associated with the factor, and a factor for terminating the trend data collection. The trend graph display device according to item 3 or 4. (6) The pair of knowledge includes at least one of data indicating the display update cycle, display width, storage cycle, display start time and end time, and display range when displaying the process values of the trend data collection items in a trend graph. 6. The trend graph display device according to claim 3, wherein the data is stored together with the trend data collection items, and the data is transmitted together with the trend data collection items. (7) The trend according to any one of claims 3 to 6, wherein the trend data collection factor registered in the knowledge base is at least one of the following: Graph display device. (a) Whether or not the process value of the target plant exceeds the alarm limit value. (b) Whether or not the process value of the target plant tends to approach the alarm limit value. (c) Whether the rate and amount of change in process values of the target plant are large. (d) Whether or not an abnormality alarm has occurred. (e) Whether the status of the main equipment of the target plant has changed. (f) Whether automation is progressing. (g) Whether a regular safety test is being conducted or whether the scheduled time for conducting a regular safety test has arrived. (h) Whether or not a pre-specified time has been reached. (i) Whether a certain period of time has passed after the state change of the main equipment of the target plant. (8) The scope of the claim further comprises factor/item changing means for executing at least one of changing, adding, and deleting the factors and process items stored in the knowledge base. The trend graph display device according to any one of items 3 to 7. (9) A patent claim further comprising item changing means for executing at least one of changing, adding, and deleting the trend data collection items stored in the trend data collection item storage means. The trend graph display device according to any one of items 3 to 8. (10) The trend data stored in the trend data collection means is displayed at the same time as the trend data is collected.
The trend graph display device described in any of the paragraphs. (11) A patent claim further comprising means for inputting a display timing on a display device of the trend data stored in the trend data collection means, and the trend data is displayed at the display timing. The trend graph display device according to any one of items 3 to 10.