JPH0261185B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a data transmission system for transmitting a large amount of information that changes extremely infrequently and information that changes extremely frequently using a transmission path with a slow transmission speed. It is related to.

[Technical background of the invention and its problems]

In a system in which transmitting and receiving stations are far away from each other and are connected to each other by a transmission line to exchange information, for example, a remote monitoring and control system, the master station's remote monitoring and control device performs remote monitoring of the slave stations. Receives various control information (process information and control parameters such as operation output signals and measurement signals) from the control device, monitors moment-to-moment changes, and changes control parameters using the slave station remote monitoring and control device as necessary. When monitoring, the process information and control parameters are sequentially received from the slave station remote monitoring and control device, and the process information is displayed on the display while being checked, and the process information is monitored. When changing the control contents, all control parameters of the master station remote monitoring and control device are replaced with new ones.

Among these, control parameters have an extremely large capacity and consist of many elements. and,
The parameters are rarely changed, even if only partially, but the control parameters may change due to an unexpected accident at the remote monitoring and control device of a remote remote station, such as a power outage or an error in received data. Therefore, there is a demand for the master station remote monitoring and control device to constantly check all control parameters of the slave station remote monitoring and control device. In addition, since the master station remote monitoring and control device monitors the control status of the slave station remote monitoring and control device, it is necessary to always obtain and display the latest information. Data transmission to the remote monitoring and control equipment includes process information and all control parameters.

Such a conventional system will be explained. In the slave station remote monitoring and control device, the process is controlled by the process control unit using the PID control parameters and the like stored in the parameter storage unit. The contents of the parameter storage section are displayed on the operation display section of the slave station remote monitoring and control device.
It is such that it can be artificially altered.

Process information such as operation output signals and measurement signals exchanged between the process control unit and the process and the contents of the parameter storage unit are transmitted and received by the transmitting/receiving unit and the transmitting/receiving control unit of the master station remote monitoring and control device and the slave station remote monitoring and control device. The information is transmitted to the remote monitoring and control device of the master station and stored in the process information storage section and the parameter storage section, respectively. The remote monitoring operation unit consists of a CRT display, keyboard, etc., and process information and parameter information are processed into a format that is easy to monitor and displayed on the CRT display for remote monitoring.

In addition, when performing control from the master station remote monitoring and control device, by operating the keyboard to generate data and commands, the transmitting/receiving unit and the transmitting/receiving control unit transmit control information to the slave station remote monitoring and controlling device. .

Here, the process information exchanged between the process control unit and the process changes from time to time according to changes in the process state, but the parameter information changes due to human operations, and usually changes in the parameter information are extremely difficult. It is rare.

When monitoring and controlling a process located far away from the remote monitoring and control unit of the remote monitoring and control unit of the master station, the process information and parameter information must be synchronized between the remote monitoring and control unit of the master station and the remote monitoring and control unit of the slave station. It is desirable that the data in the process information storage unit and the parameter storage unit in the master station remote monitoring and control device be updated at long intervals so as to be the same as the corresponding information in the slave station remote monitoring and control device.

If the information transmission speed through the data transmission path is far, it is possible to easily maintain the synchronization of information between the master station remote monitoring and control device and the slave station remote monitoring and control device, but the telephone line is used as the data transmission path. When using a low-speed transmission path (e.g., transmission speed of about 200 Bit/sec), the total amount of information will greatly increase or decrease depending on whether or not parameter information is transmitted in addition to process information, so it is difficult to update the information. The period is greatly affected.

On the other hand, the parameter information of the slave station remote monitoring and control device is also important to confirm that the control is being performed as intended. Two methods have been adopted: one method is to transmit only process information that changes far away without transmitting any information, and the other method is to transmit all process information and parameter information as shown in FIG. 3b.

However, the former has the disadvantage that the parameter information in the remote monitoring and control device of the slave station cannot be recognized at all, and the latter has the disadvantage that the update cycle of the information storage unit in the remote monitoring and control device of the parent station is slow, and the update cycle of the information storage unit in the remote monitoring and control device of the parent station is delayed. There is a drawback that it becomes difficult to ensure the simultaneity of information between the slave station and the remote monitoring and control device.

Another method is to provide a change detection circuit that detects the presence or absence of a change in the contents of the parameter storage section. Normally, as shown in Figure 3a, only process information is transmitted, and when a change in parameter information is detected, However, there is also a method of transmitting the contents of the parameter storage unit to the remote monitoring and control device of the master station.

However, with this method, if the contents of the parameter storage units of the master station remote monitoring and control device and the slave station remote monitoring and control device differ due to some kind of failure, the information cannot be changed unless the parameter information changes on the slave station remote monitoring and control device side. The drawback remains that the differences between the two are not corrected.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to transmit process information such as operation output signals and measurement signals, which have a relatively small amount of information, and some parameter-related information. It is possible to check the parameter information held by the remote monitoring and control device of the slave station without transmitting all the information, and it improves the ability to detect discrepancies in parameter information between the remote monitoring and control device of the master station and the remote monitoring and control device of the slave station to ensure that the information matches. It is an object of the present invention to provide a data transmission system that can speed up the update cycle of necessary information.

[Summary of the invention]

That is, in order to achieve the above object, the present invention provides a data transmission system that transmits a first group of information that changes frequently and a second group of information that changes less frequently and has a large capacity. means for outputting the first information group; means for holding the second information group provided on the transmitting side; means for obtaining check information indicating comprehensive characteristics of the held second information group; means for sequentially transmitting the first information group and the check information and adding and transmitting the second information group according to a command from the receiving side; and means provided on the receiving side for holding the second information group; means for capturing the received first information group provided on the receiving side; and means provided on the receiving side for capturing the received second information group held by the holding means; means for generating check information indicating the check information; means for comparing the generated check information with the received check information; and when the comparing means detects a discrepancy, instructing the transmitting side to transmit a second information group. In normal times, the first information group and the check information are sequentially transmitted, and the receiving side holds the second information group and transmits the second information group held. Check information indicating comprehensive characteristics is generated, and the generated check information is compared with the received check information to detect whether or not there is a change in the parameter information. If the result of this comparison is a mismatch, The transmitting side is instructed to transmit a second information group, and in response to this command, the transmitting side further adds a second information group to the first information group and the check information and transmits them sequentially, This allows the receiving side to monitor whether there is a change in the content without having to send the second group of information, which normally has a large capacity.
The first information that changes far away can be obtained in a fast cycle, and when a change occurs in the second information group, the transmission side is requested to transmit the second information group due to the above-mentioned discrepancy. Make it possible to match with the receiving side.

[Embodiments of the invention]

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

FIG. 1 is a block diagram showing the configuration of a system according to the present invention. In the figure, 1 is a master station remote monitoring and control device, and 2 is a slave station remote monitoring and control device, both of which are connected to a transmission path 3. connected via. Further, 4 is a process controlled by the slave station remote monitoring and control device 2.

The above-mentioned master station remote monitoring and control device 1 includes a transmitting/receiving section 11;
It consists of a transmission/reception control section 12, a process storage section 13, a parameter storage section 14, a remote monitoring operation section 15, a checksum circuit 16, and a checksum comparison circuit 17.

Of these, the transmitter/receiver 11 serially outputs necessary information and commands to the slave station remote monitoring and control device 2 side via the transmission line 3, and also receives transmission information from the slave station remote monitoring and control device 2. It has the function of converting into parallel. The transmission/reception control section 12 controls the transmission/reception section 11 and assembles transmission information and distributes and provides various information in the reception information to the process storage section 13, parameter storage section 14, and remote monitoring operation section 15. In addition, when the check sum comparison results described below do not match, or when a change detection signal is received, an instruction to send a parameter information transfer command is sent to the transmitting/receiving unit 11 in order to cause the slave station remote monitoring and control device 2 to transfer parameter information. Control such as giving.

The process information storage unit 13 stores process information received and given by the transmitting/receiving unit 11 from the slave station remote monitoring and control device 2. The parameter storage section 14 stores parameter information to be given to the remote station monitoring and control device 2 or parameter information from the remote monitoring and controlling device 2 received by the transmitting/receiving section 11 and provided.

The checksum storage section 16 receives the parameter information stored in the parameter storage section 14,
It has a function of adding these values to obtain, for example, a checksum of all the parameter information, and outputting the obtained checksum as checksum information. Also, the checksum comparison circuit 17 obtains checksum information in the received information from the transmitting/receiving section 11 and transfers it to the checksum circuit 1.
6 and detects whether or not they match with the checksum information obtained from step 6, and provides the detected information to the transmission/reception control section 12;
Alternatively, if the change detection information in the received information is flagged, it is a circuit that outputs a change detection signal. The remote monitoring operation unit 15 is composed of a CRT display, a keyboard, etc., and the process information and parameters are processed in a format that is easy to monitor and displayed on the CRT display to enable remote monitoring. When performing control from the station remote monitoring and control device 1, the transmitter/receiver 11 is controlled by operating the keyboard to generate commands.
And the transmission/reception control unit 12 can cause the slave station remote monitoring and control device 2 to transmit control information.

The slave station remote monitoring and control device 2 includes a transmitting/receiving section 21;
It consists of a transmission/reception control section 22, a process control section 23, a parameter storage section 24, an operation display section 25, a change detection circuit 26, and a checksum circuit 27.

Of these, the transmitter/receiver 21 serially outputs necessary information and commands to the master station remote monitoring and control device 1 side via the transmission path 3, and also receives transmission information from the master station remote monitoring and control device 1. It has the function of converting into parallel. The transmission/reception control unit 22 controls the transmission/reception unit 21, and assembles transmission information and provides parameter information in reception information to the parameter storage unit 24, and also when the change detection circuit 26 detects a change. Then, the change detection information is sent together with the process information, or when a parameter information transfer command is received from the parent station remote monitoring and control device 1, the parent station remote monitoring and control device 1 is sent with parameter information added, etc. An instruction is given to the transmitting/receiving section 21.

The process information storage unit 23 stores the process 4
It stores the process information obtained from the process. The parameter storage section 24 stores parameter information given from the master station remote monitoring and control device 1.

The checksum circuit 27 receives the parameter information stored in the parameter storage section 24, adds it up, obtains a checksum of all the parameter information, and uses the obtained checksum as checksum information in the transmission/reception control section 2.
It has the function of outputting to 2. Further, the process control unit 23 generates a process control output based on the parameters in the parameter storage unit 24 and provides it to the process 4 to control the process 4 and detect process information from the process 4. It has the function of providing a transmission/reception section 21.

Further, the change detection circuit 26 monitors the contents of the parameter storage section 24, detects the presence or absence of a change in the contents, and outputs a change detection signal when a change is detected.

Further, the operation display section 25 is equipped with a display device and a keyboard, and is used for inputting commands and data, and the contents of the parameter storage section 24 can be artificially changed using this operation display section 25. .

Next, the operation of the present invention will be explained using the system configured as described above.

In the slave station remote monitoring and control device 2, the process 4 is controlled by the process control section 23 using the PID control parameters stored in the parameter storage section 24.
The contents of the parameter storage section 24 are stored in the operation display section 2.
5 allows for artificial changes. Therefore, in this device, the checksum circuit 27 receives the parameter information stored in the parameter storage section 24, adds the parameter information, and calculates, for example, a checksum of all the parameter information, and then uses the checksum circuit 27 as the checksum information. In addition to outputting the information to the transmission/reception control section 22, a change detection circuit 26 monitors the contents of the parameter storage section 24 to see if there is a change in the contents, detects the information, and outputs it to the transmission/reception control section 22.

Under normal conditions, on the slave station remote monitoring and control device 2 side, process information such as operation output signals and measurement signals exchanged between the process control unit 23 and the process 4 and change detection information (whether or not there is a parameter change) flag) and parameter checksum information are transmitted to the transmission line 3 at predetermined intervals via the transmitting/receiving section 21 of the slave station remote monitoring and controlling device 2 under the control of the transmitting/receiving control section 22.

On the other hand, the master station remote monitoring and control device 1 receives the transmission information sent to the transmission path 3 via the transmitting/receiving section 11 under the control of its transmitting/receiving control section 12 . The process information is stored in the process information storage section 13, and the change detection information and checksum information are input to the checksum comparison circuit 17. The process information stored in the process information storage section 13 and the parameter information stored in the parameter storage section 14 are given to the remote monitoring operation section 15.
The remote monitoring operation unit 15 is composed of a CRT display, a keyboard, etc., and the process information and parameter information are processed into a form that is easy to monitor.
Displayed on a CRT display for distant monitoring. On the other hand, based on the change detection information sent to the checksum comparison circuit 17 via the transmitting/receiving section 11, the checksum comparison circuit 17 knows in advance whether or not there is a change in the checksum information. It is compared with the checksum of the parameters stored in the parameter storage section 14 to see if they match.
If the change detection information does not indicate a change and the comparison results match, it is assumed that the parameter information of the slave station remote monitoring and control device 2 and the master station remote monitoring and control device 1 match, and normal operation is performed. Repeat monitoring.

However, if the change detection information indicates a change,
Alternatively, if the comparison results do not match, it is assumed that the parameter information of the slave station remote monitoring and control device 2 has been changed, and the mode is switched to the change check mode, and the master station remote monitoring and control device 1 is controlled by the transmission/reception control unit 12. , gives a command to the slave station remote monitoring and control device 2 to transmit all parameter information.

As a result, the slave station remote monitoring and control device 2 enters the change check mode, and its parameter storage unit 24
Periodically transmits all stored parameter information along with process information, change detection information, and checksum information. In response to this, the master station remote monitoring and control device 1 temporarily stores the parameter information in the parameter storage section 12, adds it up to obtain a new checksum, and compares it with the checksum information sent in the next cycle. When a match is found, a command is given to the slave station remote monitoring and control device 2 to return to the normal transmission mode. As a result, the slave station remote monitoring and control device 2 returns to the normal mode and periodically transmits only process information, change detection information, and checksum information.

In addition, in the change check mode, the process information is displayed following the remote monitoring operation section 15 of the master station remote monitoring and control device 1, and the sent parameter information is also displayed. The operator on the monitoring and control device 1 side can continue to monitor process 4, and based on the displayed parameter information, it is possible to determine whether the parameter change on the remote monitoring and control device 2 was made artificially, or You can see at a glance whether the contents have changed due to an accident such as a power outage, and if there is an accident, you can issue a command to transfer the original parameter information stored in the parameter storage unit 14 of the master station remote monitoring and control device 1 to the remote slave station. It is sent to the supervisory control device 2 and stored in its parameter storage section 24. Then, process control is performed using this parameter information.

If the parameter information on the slave station remote monitoring and control device 2 side has been artificially changed,
The operator of the master station remote monitoring and control device 1 deletes the old parameter information while leaving the new parameter information sent from the slave station remote monitoring and control device 2.

As described above, the feature of the present invention is that the checksum circuits 16, 27 and the checksum comparison circuit 17 are provided. In the checksum circuit, parameter information in the parameter storage sections of both the parent station remote monitoring and control device and the slave station remote monitoring and control device are added to generate a checksum. For example, when the parameter has a 64-byte configuration, this addition is performed by performing arithmetic addition in byte units, and using the lower 8 bits (1 byte) of the added value as checksum information.

In a normal operating state where there is no change in parameter information, as shown in the time chart a in Figure 2, in addition to the process information, change detection information and parameter information (in predetermined classification units) that indicate the presence or absence of a change in parameter information ) is transmitted from the slave station remote monitoring and control device 2 to the master station remote monitoring and control device 1. When the contents of the parameter storage unit 24 change on the slave station remote monitoring and control device 2 side, change detection information indicating that a parameter change has occurred and parameter checksum information generated after the change are transferred to the parent station remote monitoring and control device. sent to. Based on this information, the master station remote monitoring and control device 1 detects that there has been a change in the parameters in the slave station remote monitoring and control device, and issues a parameter information transmission request to the slave station remote monitoring and control device 2. As shown in the time chart shown in FIG.
The data will be transmitted from there to the remote monitoring and control device 1 of the master station.

As a result, the contents of the parameter storage units 14 and 24 of the master station remote monitoring and control device 1 and the slave station remote monitoring and control device 2 match.

In addition, if the parameters of the master station remote monitoring and control device 1 and the slave station remote monitoring and control device 2 become inconsistent due to some kind of failure, the checksum comparison circuit 1
7, a discrepancy is detected and a parameter information transmission request is issued to the slave station remote monitoring and control device 2, and in the same manner as described above, the parameters of the master station remote monitoring and control device 1 and the slave station remote monitoring and control device 2 are made to match. The parameter matching operation between the parent station remote monitoring and control device 1 and the slave station remote monitoring and control device 2 is performed until they match.

In this way, in the present invention, during normal operation with no change in parameter information, in addition to process information, it is only necessary to transmit change detection information (flag) indicating the presence or absence of a parameter change and parameter checksum information. Since the amount of detection information and checksum information is usually about several bytes, the amount of information transmitted from the remote monitoring and control device of the slave station to the remote monitoring and control device of the master station is significantly reduced compared to the case where all parameter information is transmitted. As a result, it is possible to significantly reduce the rate at which the update cycle of process information is slowed down by the transmission of parameter information, and it is possible to speed up the update cycle of process information necessary for normal monitoring. .

In addition, discrepancies in parameter information between the master station remote monitoring and control device and the slave station remote monitoring and control device are constantly monitored by the parameter information checksum circuit and checksum comparison circuit. Even if a condition that cannot be detected by the parameter change detection circuit in The parameter information of the station remote monitoring and control device and the slave station remote monitoring and control device always match, and therefore high reliability of monitoring and control can be ensured.

Incidentally, in the present invention, in the change check mode, the transmission information from the slave station remote monitoring and control device may be transmitted in a pattern as shown in FIG. 2c. That is,
Here, process information, change detection information, parameter checksum information, and partial parameter information obtained by dividing all parameters into multiple units are sent in one transmission, and several transmissions are performed. This is to send all parameter information. This is effective when the amount of parameter information is extremely large or when it is desired to update process information at high speed. Further, the change detection information can also be omitted.

〔Effect of the invention〕

As described in detail above, according to the present invention, during normal operation without parameter changes, it is only necessary to transmit process information, change detection information, and parameter checksum information; Since the amount of information is small compared to the case where all parameter information is added and transmitted,
The amount of information transmitted from the slave station remote monitoring and control device to the master station remote monitoring and control device can be significantly reduced.
This makes it possible to significantly reduce the rate at which the update cycle of process information is slowed down by the transmission of parameter information, so it is possible to secure sufficient information even when using a transmission path with a slow transmission speed, and it is also possible to Parameter discrepancies between the monitoring and control equipment and the slave station remote monitoring and control equipment are constantly monitored by comparing parameter checksums. Even if, for some reason, the slave station remote monitoring and control device is unable to detect a parameter change, such as when there is no change in the checksum information itself, it is not possible to provide change detection information indicating that a change has occurred.
Since the parameter information is automatically matched between the parent station remote monitoring and control device and the slave station remote monitoring and control device, the parameter information of the parent station remote monitoring and control device and the slave station remote monitoring and control device is always match, and therefore, it is possible to provide a data transmission system having characteristics such as ensuring high reliability of supervisory control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Figures 2 a to c are time charts showing patterns of transmission information from the slave station remote monitoring and control device to the master station remote monitoring and control device in the present invention, and Figures 3 a and b are from the conventional slave station remote monitoring and control device. 3 is a time chart showing a pattern of information transmitted to a master station remote monitoring and control device. 1... Master station remote monitoring and control device, 2... Slave station remote monitoring and control device, 3... Transmission path, 4... Process,
11, 21... Transmission/reception unit, 12, 22... Transmission/reception control unit, 13... Process information storage unit, 14, 2
4... Parameter storage unit, 15... Remote monitoring operation unit, 16, 27... Checksum circuit, 17...
Checksum comparison circuit, 23...process control section, 25...operation display section, 26...change detection circuit.

Claims (1)

[Claims] 1. In a data transmission system that transmits a first information group that changes frequently and a second information group that changes less frequently and has a large capacity, the first information group provided on the transmitting side includes: an output means, a holding means for a second information group provided on the transmitting side, a means for obtaining check information indicating comprehensive characteristics of the held second information group, and normally, the first information group. means for sequentially transmitting the check information and the check information, and adding and transmitting a second information group according to a command from the receiving side; and means provided on the receiving side for taking in the received first information group; , a means provided on the receiving side for holding the received second information group; and a means provided on the receiving side for generating check information indicating comprehensive characteristics of the second information group held by the holding means. means for comparing the generated check information with the received check information; and means for instructing the transmitting side to transmit a second information group when the comparing means detects a discrepancy. data transmission system. 2. The data transmission system according to claim 1, wherein the check sum obtained by adding the second information group is used as the check information.