JPH0475103A - Process control system - Google Patents

Abstract

PURPOSE:To reduce a load on a data transmission line by simplifying data transmission between a process controller and another transmission station ;by performing the multi-address communication of data held with the process controller when it is changed form the process controller to another station. CONSTITUTION:When the data held with the process controller 13 is changed, changed data is muti-address-communicated form the process controller to the transmission stations 14, 15, and 17. At the transmission stations 14, 15, and 17, the data is updated to multi-address-communicated data when it shows the data filed in the internal memory 21-23 of its own station. Thereby, it is possible to remarkably reduce the load on the transmission line 1 compared with the case that the data from the process controller 13 is read out by all the transmission stations 14 at a constant cycle, and also, to keep concurrency between the data in the process controller 13 and that in the internal memory 21-23 of the transmission station 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] [Field of Industrial Application] The present invention relates to a process control system in which a plurality of devices are connected to a data transmission path.

[Conventional technology]

FIG. 3 shows the basic system configuration of a process control system used for process control in factories and the like. That is, the conventional process control system has a process controller 3 on the same transmission line 1 that directly controls the process 2.
, an operator console 4 for inputting instructions from an operator to the process controller 3, a database 5 for storing various basic data related to process control, and a gateway station 7 for connecting with a host computer 6. There is.

In the process control system configured in this way, the operator console 4 controls the data transmission path 1 and reads out the corresponding data from the process controller 3 as needed in order to monitor and display process data or parameters. The data is imported into the own station and the above processing is performed. Similarly, in order to control, monitor, manage, display, etc. 1 the process data or parameters on the host computer 6, the gateway station 7 controls the data transmission path 1, reads the relevant data from the process controller 3, and executes the above processing. ing.

However, if the corresponding data were read from the process controller 3 via the data transmission line 1 each time each transmission station 4 to 5.7 needed data, it would take a long time to transmit the data. The disadvantage is that the responsiveness of the data is lacking.

Furthermore, a system has been proposed in which the process controller 3 stores data required by the own station in the memory of the own station. In this system, each transmission station constantly monitors the data it needs among the data held by the process controller 3, and if the relevant data is changed, the corresponding data of the own station is also changed. are doing. For this purpose, the corresponding data of the local station is read from the process controller 3 at regular intervals to constantly update the file in the local station memory. Therefore, the same data held by the process controller 3 is always held in its own memory, improving data responsiveness.

However, since all the transmission stations read the relevant data from the process controller 3 at regular intervals, the processing for transmission increases and the load on the transmission path 1 increases, which may result in data congestion. Moreover, depending on the read cycle, changes in the data of the process controller 3 may not be detected, and data simultaneity may not be guaranteed.

[Problem to be solved by the invention]

Therefore, in conventional process control systems, the load placed on the data transmission path is large, which can cause data congestion and affect other processes, and what is more, the data held by the process controller and the data stored in its own memory are There is also a possibility that the data stored in the file does not match.

The present invention has been made in view of the above-mentioned circumstances, and can simplify data transmission between a process controller and a transmission station, reduce the burden on the data transmission path, and improve data responsiveness. The purpose is to provide a process control system that provides

[Structure of the Invention] [Means for Solving the Problem] In order to achieve the above object, a first invention provides a process control system in which a process controller and a plurality of transmission stations are connected by the same transmission path, and the process controller In the process control system, data related to process control held by the process controller is transmitted to a predetermined transmission station via the transmission path, and the data held by the process controller is rewritten by a write request from the transmission station. An internal memory provided in each transmission station and having a data area in which data required by the own station is written among the data held by the process controller; broadcast notification means for broadcasting the changed data from the process controller to other transmission stations when the data held by the process controller is changed due to data transmission between the process controller and the respective transmission stations; If the broadcast notification data corresponds to the data written in the data area of the internal memory,
and change data monitoring means for updating the data to the data for which the broadcast notification has been made, and as a second invention, a process control system is further provided with a system having the above configuration, and further notifies each transmission station of the broadcast notification. A common memory is provided that is notified of changes in data that are not notified by the process controller, and when a change in data required by the own station is notified to this common memory, a request to transmit the data is output to the process controller. It was configured as follows.

[Effect]

By taking the above measures, according to the first invention, when the data held by the process controller is changed, the changed data is broadcasted from the process controller to each transmission station. be done. In each transmission station, if the broadcast-notified data is data stored in its own internal memory, it is updated to the broadcast-notified data. Therefore, the load on the transmission path is significantly reduced compared to when all transmission stations read data from the process controller at regular intervals. Maintains sexuality.

According to the second aspect of the present invention, in addition to the above-mentioned effects, the common memory is notified of a change in data even if it is data of a process controller but the change is not notified in a broadcast manner. Each transmission station outputs a request to transmit the data when there is a change in the data stored in the common memory. By doing this,
Even if the capacity of the common memory is limited, the simultaneity of the data held by the process controller and the data in the internal memory of each transmission station is maintained.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a system configuration diagram of a process control system according to a first embodiment. In this process control system, a process controller 13 is connected via a data transmission line 1 to an operator console 14 serving as a transmission station. Database 15
．． It is connected to gateway station 17. Although the process controller 13 is also included in the transmission station in a broad sense, the term transmission station is not used with respect to the process controller 13 in order to distinguish it from other transmission stations.

The process controller 3 includes an internal memory 18 that holds process data and various parameters, and a broadcast notification unit 19 that broadcasts the data to each transmission station when there is a change in the data in the internal memory 18. and original process control functions. Each transmission station issues a read request and a write request to data stored at a predetermined address of this internal memory 11.

On the other hand, the internal memory 21.2 of each transmission station 14, 15.17
2.23, a data area is formed in which data required by the local station among the data stored in the internal memory 18 of the process controller 13 is written. Furthermore, each transmission station 14゜15.17 receives the broadcast notification from the process controller 13, and if the received data is filed in the data area of its own station, it sends the data to the broadcast notification. A changed data monitoring unit 20 is provided to update the updated data.

Next, data transmission in this embodiment will be explained in detail.

At the time of initialization such as system initialization, each transmission station reads data necessary for itself from the process controller 13 and stores it in the corresponding data area of the internal memory 21, 22, 23 of the own station.

Suppose that data such as a certain parameter stored in the internal memory 18 of the process controller 13 is subsequently changed by a write request to the process controller 13 from the operator console 14, for example. When the data is changed as described above, the broadcast notification unit 19 of the process controller 13 broadcasts the changed data to all transmission stations 14, 15, and 17.

On the other hand, each transmission station 14, 15, 17 receives the broadcast notification from the process controller 13 at the change data monitoring unit 20. The change data monitoring unit 20 checks whether the data is the received broadcast notification data or the data filed in the internal memory 21 to 23 of its own station, and checks whether the data is the filed data (needed data). If so, the corresponding data is updated to the data for which the notification was sent. Furthermore, if the file does not contain the corresponding data, the broadcast notification data is canceled.

Therefore, each transmission station 14, 15, 17 can read data that is held by the process controller 13 and required by the own station by accessing the internal memory 21 to 23 of the own station. can.

In this way, according to this embodiment, each transmission station 14°15.17
are provided with internal memories 21 to 23 and a changed data monitoring unit 2o, and the process controller 13 is provided with a broadcast notification unit 19 that broadcasts the changed data of its own station to all transmission stations, and each transmission station 14, 15.17 Of the notifications received by the change data monitoring unit 20 of the station, only the data required by the local station are imported and the files in the internal memory are updated, so the data held by the process controller 13 and the data held by each transmission station are It is possible to maintain simultaneity with the data being sent, and achieve fast response. Furthermore, compared to the conventional method in which all transmission stations read out data from a process controller at regular intervals, the load on the data transmission path can be significantly reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.

This embodiment is an example in which, in addition to the process control system shown in the first embodiment, the process controller 13 and each transmission station each have a common memory 30 that is common for transmission.

The common memory 30 is data held in the process controller 13.
A counter area is formed to notify that data that is not broadcast-notified (hereinafter referred to as "secondary data" with respect to data that is broadcast-notified) has been changed/updated.

For example, when the secondary data of the process controller 13 is changed due to a write request from the operator console 14, the common memory 30 provided in the process controller 13 counts up the count value of the counter area corresponding to the data. do. The change information of the secondary data, which is sequentially written into the common memory 30 provided in the process controller 13, is scanned to the common memory 30 of each transmission station in a short scan period.

Each transmission station constantly monitors changes in the counters in the common memory 30 provided in its own station, and if there is a change in secondary data required by its own station, the process controller 1
3 and imports it into its own station.

As described above, according to this embodiment, the same effects as those of the first embodiment can be achieved, and furthermore, change information of secondary data that is not broadcasted is notified to the common memory 30 that is common for transmission, and Since data is read from the process controller 13 only when there is a change in the secondary data required by a station, even if it is not possible to scan and transmit the data required by all transmission stations, each transmission station can read the data required by each transmission station. Changes in secondary data can be detected, and the data can be sent to the process controller 13.
It can be read out quickly from

[Effects of the Invention] As detailed above, according to the present invention, data transmission between the process controller and the transmission station can be simplified, the load on the data transmission path can be reduced, and data responsiveness can be improved. can provide a process control system that can

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a process control system according to a first embodiment, FIG. 2 is a block diagram of a second embodiment, and FIG. 3 is a block diagram of a conventional process control system. 1... Data transmission path, 2... Process, 13...
Process controller, U4... Operator console, 15... Database, 16... Upper computer, 17... Gate controller, 18゜2
1 to 23...Internal harpoon, 19...Broadcast notification section, 0.
...Update data monitoring unit, 30...Common memory.

Claims (2)

[Claims] (1) A process controller and a plurality of transmission stations are connected by the same transmission path, and data related to process control held by the process controller is transmitted to a predetermined transmission station via the transmission path, and data from the transmission station is In a process control system in which data held by the process controller is rewritten by a write request, among the data provided in each transmission station and held by the process controller, the data required by the own station is When the data held by the process controller is changed due to data transmission between the internal memory in which the data area to be written is formed and the process controller and a predetermined transmission station, the changed data is stored. Broadcast notification means for broadcasting notification from the process controller to other transmission stations; and broadcast notification means provided in each of the transmission stations, the data for which the broadcast notification was made corresponds to the data written in the data area of the internal memory. If so, a changed data monitoring means for updating the data to the broadcast-notified data. (2) Each of the transmission stations has a common memory that is notified of data changes that are not notified by the broadcast notification, and when the common memory is notified of data changes that are required by the own station, Claim 1, further comprising: outputting a request for transmitting the data to the process controller.
Process control system described.