JPH0367399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a remote monitoring and control device, and particularly to a remote monitoring and control device that prevents multiple communications between a control center and a controlled facility.

[Technical background of the invention]

FIG. 3 is a block diagram of a conventional remote monitoring and control device, which consists of a control center device (master station) 10 and a controlled center device (slave station) 20. and control center device 10
The control command from is received by the receiving circuit 21 of the controlled station 20 via the transmission path, and this is sent to the processing circuit 22.
This is a series of operations in which the data is transferred to the control center for processing, and the results or data from the controlled center are sent back to the control center via the transmission circuit 23. In this type of device, a control center device 10 and a controlled center device 20
The same data may be communicated multiple times. Here, as an example of a transmission method in which the same data may actually be communicated twice, a data format as shown in FIG. 4 can be considered.
The format shown in FIG. 4 consists of a data section 31, a check code 32, and an error bit 33. Then, only when the slave station that received the first data from the master station receives the second data and there is no error, it returns the data to the master station and considers the contact complete.
If an error is detected, error bit 3
One method is to send the data back with a number 3 attached, and the master station that receives this retransmits the data from the first time.

[Problems with background technology]

When using the above-mentioned transmission method, there is a possibility that error bits may be added to the data sent back from the slave station to the master station due to the influence of noise, and therefore the same data will be communicated multiple times.
In this case, processing this data as it is will result in a double operation. That is, there is a possibility of malfunction in the case of control in which the amount of control output is changed depending on the number of times of control, for example, tap control of voltage step-up or step-down in an electric power system.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a remote monitoring and control device that can prevent malfunctions or unnecessary operations due to multiple control.

[Summary of the invention]

In the present invention, data communicated one time before is stored in an old data storage buffer, and by comparing the latest data and the data one time ago using a comparison circuit, it is possible to determine whether or not the data is the same. The process is performed only when the data is different.

[Embodiments of the invention]

Examples will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of a remote monitoring and control device according to the present invention, and shows only the block diagram of the internal circuit. Reference numerals 21 and 22 in the figure correspond to those in FIG. 24 is an old data storage buffer in which the previous data is stored. 25 is a timer, 26 is a comparison circuit, 27
is an alarm circuit, and 28 and 29 are AND circuits. In short, new data received by the receiving circuit 21 passes through the old data storage buffer 24 and the comparing circuit 26 to the processing circuit 22 or the alarm circuit 27.

Next, the operation will be explained. First, the new data received by the receiving circuit is compared with the old data stored in the old data storage buffer 24 by the comparison circuit 26.
Then, only in the case of a mismatch, the data is passed to the processing circuit 22, and the result is further stored in the old data storage buffer. If they match, the alarm processing circuit 27
and stored in the old data storage buffer 24. Also, timer 25 is installed in the old data storage buffer.
The contents of the buffer will be deleted after a certain period of time.

As described above, even if the same data is communicated multiple times, the operation is limited to one time, and if the same data is communicated at different times, it can be considered as separate communications.

FIG. 2 shows another embodiment of the invention.

In this embodiment, a plurality of old data storage buffers are created and compared with n pieces of data communicated within a certain period of time. In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. 241 to 24n are a plurality of old data storage buffers, in which received data are stored in that order. 251 to 25n are timers, 261
is a comparison circuit and each old data storage buffer 24
Outputs from 1 to 24n are introduced. 30 is a storage buffer selection circuit which selects the oldest stored old data position. In this case, the new data received by the receiving circuit 21 is compared with the old data stored in the plurality of old data storage buffers 241 to 24n in the comparing circuit 261, and only in the case of a mismatch is passed to the processing circuit 22 and stored. Through the buffer selection circuit 28, the data is stored in the oldest old data storage buffer to be stored. Further, if there is a match as described above, the information is passed to the alarm circuit 27. The data is then stored in the same old data storage buffer mentioned above through the storage buffer selection circuit 28. Each of the old data storage buffers 241 to 24n has a timer 25.
1 to 25n are attached, and the contents of the buffer are erased after a certain period of time has passed. As described above, not only continuous data but also n consecutive data within a certain period of time can be compared, and the operation can be performed only once.

〔Effect of the invention〕

As explained above, according to the present invention, all received information is unconditionally tested for continuous reception signals, and the test time is set within an arbitrary set time by a timer, so that the transmission timing is It is possible to prevent continuous reception of the same signal within a specified time regardless of the transmission time, and the transmission check is also simple:
In addition to checking 1, it is also possible to check n:n data transfer.

[Brief explanation of drawings]

Fig. 1 is a block diagram of one embodiment of the remote monitoring and control device according to the present invention, and is a block diagram of an internal circuit to which a multiprocessing prevention circuit is applied, Fig. 2 is a block diagram of another embodiment, and Fig. 3 is a block diagram of a conventional device. The configuration diagram to be described, FIG. 4, is a format configuration diagram of a transmission method in which the same data may arrive multiple times. 10... Control center device, 20... Controlled center device,
21... Receiving circuit, 22... Processing circuit, 23...
Transmission circuit, 24,241-24n...Old data storage buffer, 25,251-25n...Timer, 2
6,261...Comparison circuit, 27...Alarm circuit, 2
8, 29...AND circuit, 30...Save buffer selection circuit.

Claims (1)

[Claims] 1. A receiving circuit that receives data output from a control center device via a transmission path, a processing circuit that processes data from the receiving circuit, and a transmitting circuit that sends the processing results and data back to the control center device. In a remote monitoring and control device, an old data storage buffer with a timer and a comparison circuit are provided between the receiving circuit and the processing circuit, and the contents of the old data received in advance within a predetermined time determined by the timer and the comparison circuit are provided. A remote monitoring and control device that compares the contents of new data and validates the new data only if there is a mismatch.