JPH10124116A - Method for collecting trend data in controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the overflow of a buffer memory and also to reduce the load of transmission, by obtaining sufficient memory capacitance necessary for the trend display of a whole system from the total-sum of the number of recording points in the whole system and using it as a transmission buffer. SOLUTION: A controller 2 collects data from a sensor, etc., 5 and transmits to a central monitoring device 1 by way of a communication line 4. When trend data is transmitted, trend definition 31 given from a supporting device 3 at the time of initialization is referred to so as to execute transmission. Trend definition 31 is defined at every recording point. At the time of initial processing, referencing is repeatedly executed for the portion of a number of trend definition storage so that a data collection cycle at every station and the correspondence file of the number of the recording points are generated and, then, the total-sum of the number of the recording points are operated. The size of the buffer memory is decided by the total-sum of the number of the recording points and also the cyclic setting value of trend data transmission is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collecting trend data of a control device, which transmits plant data collected with reference to a trend definition of a support device to a central monitoring device of a request source.

[0002]

2. Description of the Related Art A control device temporarily collects collected plant data in a transmission buffer memory (hereinafter, referred to as a transmission buffer) having a fixed memory capacity provided for each central monitoring device of a transmission destination. The collected plant data is transferred to a transmission work area provided for transmission, from which it is cyclically transmitted to the central monitoring device. On the central monitoring device side, data to be displayed as a trend from the received data is stored.

[0003]

Generally, the transmission buffer and the transmission work area of the control device each have a certain amount of memory capacity determined by the performance and economy of the system. When there are a plurality of central monitoring devices at the data transmission destination, the collected data is stored separately in transmission buffers provided for the respective central monitoring devices at the transmission destination, and these are cyclically transmitted to the transmission device of the control device. Since the data is transmitted from the area and transmitted to the central monitoring device via the communication line, no problem occurs in data collection.

[0004] However, if a biased trend definition is provided such that all trend data is transmitted intensively to one specific central monitoring device due to the operational conditions of the system, transmission is performed for each transmission destination. Since the buffer capacity and the collection period are fixed, the data transfer from the transmission buffer to the transmission work area cannot keep up with the data collection period of the transmission buffer plant, causing the transmission buffer to overflow and causing data loss, etc. The system specifications may not be satisfied.

[0005]

The problem can be solved by simply increasing the capacity of the transmission buffer of the control device or by increasing the data collection period, but this does not involve economics. Therefore, as a method of using the buffer memory area, a sufficient memory capacity necessary for displaying the trend of the entire system is obtained from the total number of recording points of the entire system and is used as a transmission buffer, and the rest is used for other purposes such as arithmetic processing In this way, the entire memory can be used without waste.

Further, by making the data collection cycle variable and increasing the transmission cycle as the total number of recording points increases, transmission load can be reduced and transmission can be performed efficiently.

[0007]

FIG. 1 shows a system configuration of the present invention. The control device 2 collects data from the sensors 5 and transmits the data to the central monitoring device 1 via the communication line 4. When transmitting the trend data, the trend data 31 is given by referring to the trend definition 31 given at the initial time from the support device 3.

FIG. 2A shows a trend definition stored in the memory area of the support device 3. FIG. 2B shows the contents of each trend definition shown in FIG. 2A. FIG.
As shown in (a), the trend definition is defined for each recording point, and in the embodiment of the present invention, a maximum of 256 definitions can be stored. In the initial processing, a file corresponding to the data collection cycle and the number of recording points for each station is created as shown in FIG. 3 by repeatedly referring to the number of times where the trend definition is stored. Is calculated.

FIG. 4 is a graph showing the number of recording points × 1 from the total number of recording points.
This is a file corresponding to the buffer area size for each station created so as to have a buffer memory size of 0. Here, the size of the buffer memory is calculated as the number of recording points × 1.
The value of 0 is set to × 10 in consideration of the margin since the data transmission timing is about five times the data collection timing.

Further, the set value of the trend data transmission cycle is determined from Table 1 based on the total number of recording points. This cycle setting value is for activating the transmission activation process, and the unit is represented by 200 mSEC.

[0011]

[Table 1] This cycle setting value is used in transmission processing. Transmission processing is 2
It starts up at a fixed cycle of 00 msec, but when counting up to this cycle set value, transmission processing is performed, and the transmission cycle to each station is made variable. FIG. 5 shows a flowchart of the message transmission activation process of the control device, and FIG. 6 shows details of the message transmission process in the flowchart of FIG.

In FIG. 5, when an interrupt 501 is received from the central monitoring apparatus 1, the processing flow on the left side is performed, the message transmission processing 502 is completed, and if the transmission of all the interrupt stations is completed 503, the interrupt flag is set to OF.
The process ends after performing F504. If there is no interruption, the processing is performed at a fixed cycle, and the processing flow is on the right side. That is, this processing flow is entered at regular intervals (200 msec), and a message transmission process 506 and 505 where the number of entries reaches the cycle set value set for each destination station are performed.

FIG. 6 shows a flow until data collected by the control device is transmitted from the transmission buffer 21 to the destination central monitoring device 1 via the transmission work area 22. When this flow is started, the flow first enters the processing flow on the right side, creates 601 trend data, transfers it to the transmission work area, turns on the transfer completed flag 602, and ends.

When the second activation is started, the process enters the middle processing flow, receives a message transmission request 603, starts transmission via the communication line 4 to the central monitoring device 1 of the transmission destination, and sets the transmission processing activated flag to ON 604. And exit.
When the third activation is started, the process flow on the left side is entered, and it is checked whether the transmission has been completed correctly 606, the two flags are turned off 607 and 608, and the message transmission is completed.

[0015]

By making the collected data buffer memory and the transmission cycle variable even for a biased trend definition, overflow of the buffer memory can be prevented and the transmission load can be reduced.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

2A is a diagram showing a trend definition, and FIG. 2B is a diagram showing the contents of the trend definition.

FIG. 3 is a diagram showing a file corresponding to a data collection period and the number of recording points for each station.

FIG. 4 is a diagram showing a file corresponding to a buffer area size for each station.

FIG. 5 is a flowchart of a message transmission start process.

FIG. 6 is a flowchart of a message transmission process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Central monitoring device, 2 ... Control device, 3 ... Support device, 4 ...
Communication line.

Claims (2)

[Claims] 1. A buffer memory for storing collected plant data for each central monitoring device of a transmission destination, a work area for transmitting plant data stored in the buffer memory to the central monitoring device, and a transmitted plant Of a control device that has a plurality of central monitoring devices that monitor the data of the trend data as trend data, a support device that has a trend definition that defines the content of each trend data, and a communication line that exchanges data between these devices. In the data collection method, the total sum of the trend data transmission destination central monitoring device and the total number of recording points of the central monitoring device is calculated by referring to the trend definition given by the support device, and the buffer memory capacity is calculated based on the recording point number. A trend data collection method for a control device, wherein the trend data is collected from a total sum. 2. The trend data collection method for a control device according to claim 1, wherein the trend data transmission cycle for each central monitoring device to which the trend data is transmitted can be set according to the total of the recording points. Characteristic method of collecting trend data for control devices.