JPH0126098B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a data communication system in a distributed control device.

A distributed control device is a system in which multiple control stations are distributed at locations to be controlled, and each control station is in charge of control of that part, and these control stations are interconnected via communication lines, and one control station is connected to this communication line. Alternatively, multiple monitoring and operating stations may be connected to allow an operator to monitor and operate the entire device. The monitoring operation station is equipped with a graphic display device and a keyboard.The various screens of the graphic display device display the status of the controlled object and the status of the control device itself, and the keyboard allows various operation commands to be sent to the control device. It is beginning to be given to

Data for displaying the status of the controlled object and the control device itself is collected from each control station to the monitoring operation station through communication, and is appropriately processed and displayed at the monitoring operation station. In that case, some of the data relating to each control station is previously held in the monitoring and operating station and does not need to be collected from each control station, in particular by communication. When the distributed controller is a process controller, such data may include tag names of controlled variables, tag comments, engineering units, controller instrument diagrams, annunciator strings, and the like. These data are
Because it is meaningful to the operator,
It is usually provided only at the monitoring and operating station, not at each control station. When there are a plurality of monitoring operation stations, each monitoring operation station is provided with such data.

Even if these data are set once,
Although it may be changed later due to maintenance etc., if there are multiple monitoring operation stations and some data is common among them, the monitoring operation station that has such data If a change is made in one, all other monitoring and operating stations that have the same data must also be changed to match.

In that case, it would be troublesome for an operator to correct the corresponding data at each monitoring operation station, so when data maintenance is performed at a certain monitoring operation station, communication from that monitoring operation station It is desirable that the data for all stations involved be corrected automatically. To do this, it is necessary to recognize which monitoring operation station the corrected data is common to and communicate it to the corresponding station. However, since each monitoring operation station is generally independent and determines the necessary data independently, it is not easy to recognize which data is common to which station.

An object of the present invention is to provide a communication system in which a monitoring operation station that has changed data does not need to be aware of the correspondence between data and stations when communicating with other monitoring operation stations for data matching. The objective is to provide a data communication method that is less burdensome.

In the present invention, a plurality of stations each having a processor, a main memory, an input/output device, and a communication control device capable of direct memory access to the main memory are connected to each other by a communication line, and each station In a distributed control device, each of which has data common to data of other stations, the transmitting station has task 1, which is activated when the common data is matched, to the receiving station, which will be described later. Start task 3 and start the timer for the specified time.
WAIT, and when the flag set by task 2, which will be described later, is established within the timer limit.
POST, transmitting the address of the data to be matched in the main memory to the receiving station (described later), starting task 4 (described later), and waiting for the matching completion communication from the receiving station; and the receiving side, which will be described later. Task 2, which is activated by communication from the station, is provided with a procedure for setting a flag according to the confirmation response, and the receiving station has a procedure that is activated by Task 1 of the sending station. As task 3, we set a timer for a predetermined period of time, wait for a shared resource to become free, and when the shared resource becomes free within the timer's time limit, we send a confirmation response, and when the timer times out, we send a rejection response. A procedure for activating Task 2 of the sending station in response to a reply to the sending station, and as Task 4 activated by Task 1 of the sending station, the self station's own address among the addresses received from the sending station. It receives the address of data that is common to the data, performs communication to read the main memory of the transmitting station using this address, matches its own data with the read data, and sends a match completion signal when the match is completed. The above object is achieved by a distributed control device characterized by providing a procedure for sending a reply to a sending station.

Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 1 is a conceptual block diagram of a distributed control device to which the present invention is applied. In Figure 1, 1
1, 12, . . . 1m are monitoring operation stations, 2 is a communication line, and 31, 32, . . . 3n is a control station. Monitoring operation station 1i (i=1 to m)
and the control station 3j (j=1 to n),
It has an intelligence consisting of a microprocessor, etc., and each function is achieved by the function of this intelligence.

The detailed configuration of each station is shown in Figure 2, which includes a communication control device FCA as an interface to the communication line, and a processor CPS.
, main memory MMU, and input/output device I/O
are interconnected by a data bus BS.

The communication control device FCA has intelligence provided by its own microprocessor or appropriate firmware, and uses this intelligence to autonomously control communications. The communication control unit FCA also has a direct memory access (DMA) function for the main memory MMU, which allows data to be communicated with other stations to be transferred to the main memory MMU. Read and write directly.

The main memory MMU stores appropriate programs for the monitoring operation station or the control station, depending on the characteristics of the station, so that each station performs its respective functions.

In the monitoring operation station 1i, a graphic display device and a keyboard are connected to the input/output device I/O, and in the control station 3j, various input/output devices for process control are connected.

Each monitoring operation station 1i is assigned a characteristic in advance, and is used by an operator according to its characteristic. In each monitoring operation station 1i, various types of data are prepared depending on the characteristics of each station. Some of that data is from monitoring and operation stations 11 to 1m.
may be common to some of the following.

Regarding such data that may exist in common,
A program as shown in FIG. 3 is provided at each monitoring and operating station 1i in order to correct data in other monitoring and operating stations when changes are made at one monitoring and operating station.

In FIG. 3, P is a monitoring operation station on the sending side, and S is a monitoring operation station on the receiving side. The sending station P has task 1 and task 2.
The receiving station S has two programs, task 3 and task 4. Actually, the monitoring operation station 11~
1m can each act as a sender and a receiver, so it has all the programs for tasks 1 to 4, but the figure shows only the tasks that are in the active state. The task number is common throughout the control device.

Task 1 is a program that is activated by an operator's keyboard operation after data has been changed, and is for urging the other station S to make common data consistent.
Task 2 is activated by a response from the partner station S, and sets a flag indicating the arrival of the response. Task 3 and task 4 are both activated by communication from the sending station P, of which task 3 is for returning a response to the sending station P, and task 4 is for matching common data. It is for the purpose of

Matching of common data by these tasks is performed as follows. First, when task 1 is started at the sending station P, step p1
As a result of the operation, communication for activating task 3 of the partner station S is performed. Communication is 1:1
Alternatively, the ratio is 1:n. and stage p2
At this point, a timer is set and the station waits for a response from the other station in the WAIT state. The operating status of the transmitting station P is displayed on a graphic display.

Task 3 is started at the destination receiving station S, and waits for other tasks occupying shared resources such as the graphic display device and the multiple use area of the main memory MMU to finish due to the operation in step s1. . When waiting, a timer is set, and according to the operation of step s2, when another task finishes within the time limit value of the timer, it occupies the shared resources and returns a confirmation response, and when the time has expired, it is rejected. reply to the sender. When a confirmation response is returned, the graphic display shows that the station S has reached the data matching state.

At the sending station P, when a confirmation response is received, task 2 is activated and a flag indicating that a confirmation response has been received is set. When the flag is set, task 1 performs POST and performs data transmission to the other station by the operation of step p3. If the flag is not set within a predetermined time period, further communication is discontinued.

The data transmitted in step p3 is not the data itself that has been changed due to maintenance or the like, but the address of that data in the main memory. This address includes information indicating the attributes of the data, such as the station number of the control station 3j to which the data relates.

According to such data communication, task 4 is activated at the receiving station S, and step 4 is started.
The following data processing is performed by the operation of s3.

That is, the receiving station S receives the address only for the data in its own station based on the attribute information included in the received data, and uses that address to send the main memory MMU to the transmitting station P. Performs readout.

As a result, in the transmitting station P, the main memory MMU is read by the DMA operation of the communication control device FCA, and the read data is transmitted to the receiving station S.

The receiving station S uses the received data to correct its own data, and when the correction is completed, it returns a completion notification to the transmitting station P through the operation of step s4. The completion notification is returned immediately if the required address is not found in the received address.

The transmitting station P confirms the completion notification through the operation in step p4, and if there is other data to be matched, it performs the same communication as above for those data. In the case of 1:1 communication, when the matching operation for one monitoring operation station is completed, the matching operation for the next monitoring operation station is performed in the same way. In the case of 1:n communication, processing is performed on a first-come, first-served basis. Such processing is possible because the task number is common to all control devices.

In this way, the transmitting station P transmits all the addresses of the changed data without being aware of the correspondence with other stations,
Since the receiving station S selects only the address of the data it needs from among them and reads it from the other party's memory using DMA, the communication burden on the transmitting station P is greatly reduced.

Furthermore, the data matching operation is performed by occupying shared resources by each task for matching, at least in the station S on the receiving side, and no other task is executed during the matching operation. It's becoming like that. Since these operating conditions are displayed on the screen of the graphic display device and made visible to the operator, inconsistencies in data may occur due to unique maintenance at stations that are consistent. There is no.

Furthermore, since the task number is common to all control devices, even when data matching requests are generated intensively from a plurality of stations, they are received and processed on a first-come, first-served basis, so there is no confusion.

Although the present invention has been described above with reference to preferred embodiments, the present invention may have various embodiments within the scope of the claims.

[Brief explanation of drawings]

FIG. 1 is a conceptual block diagram of a distributed control device to which the present invention is applied, FIG. 2 is a somewhat detailed block diagram of a monitoring operation station and a control station, and FIG.
The figure is an explanatory diagram of the operation of the embodiment of the present invention. 11~1m...Monitoring operation station, 2...
Communication line, 31-3n...control station,
FCA...Communication control device, CPU...Processor,
MMU...main memory, I/O...input/output device.

Claims (1)

[Claims] 1 A plurality of stations each having a processor, a main memory, an input/output device, and a communication control device capable of direct memory access to the main memory are interconnected by communication lines. , in a distributed control device in which each station has data that is common to the data of other stations, the station that is the sending side has a task 1 that is activated when the common data is matched, which will be described later. Start task 3 on the receiving station and start the timer for the specified time.
WAIT, and when the flag set by task 2, which will be described later, is established within the timer limit.
POST, transmitting the address of the data to be matched in the main memory to the receiving station (described later), starting task 4 (described later), and waiting for the matching completion communication from the receiving station; and the receiving side, which will be described later. Task 2, which is activated by communication from the station, is provided with a procedure for setting a flag according to the confirmation response, and the receiving station has a procedure that is activated by Task 1 of the sending station. As task 3, we set a timer for a predetermined period of time, wait for a shared resource to become free, and when the shared resource becomes free within the timer's time limit, we send a confirmation response, and when the timer times out, we send a rejection response. A procedure for activating Task 2 of the sending station in response to a reply to the sending station, and as Task 4 activated by Task 1 of the sending station, the self station's own address among the addresses received from the sending station. It receives the address of data that is common to the data, performs communication to read the main memory of the transmitting station using this address, matches its own data with the read data, and sends a match completion signal when the match is completed. A distributed control device comprising a procedure for sending a reply to a sending station.