JPH03280723A - Remote monitor control system - Google Patents

Abstract

PURPOSE:To reduce the communication cost by hooking on a public telephone line when a restoration signal is received. CONSTITUTION:When a private line 7 is faulty, a master station 1 selects an active/standby line changeover circuit 3 to the position of a standby line to call all slave stations 21-2n via a public telephone line 80 and to output a connection command signal. when a call comes to public telephone lines 81-8n, the slave stations 21-2n start public telephone line connection circuits 61-6n to reply the call, turn active/standby changeover circuits 51-5n to the position of the standby line upon the receipt of the connection command signal to connect themselves to a controller to be monitored and all the slave stations 21-2n are connected to a monitor controller of a master station 1 via a public line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a remote supervisory control system in which one supervisory control station and at least one monitored control station are connected through one dedicated line.

[Conventional technology]

Conventionally, this type of remote monitoring and control system has a monitoring and control station (
In order to carry out supervisory control data communication between the monitored control station (hereinafter referred to as the master station) and the monitored control station (hereinafter referred to as the slave station), two dedicated lines, a working line and a standby line, are used, and when the working line fails, the line is switched to the standby line. By using this, communication failures due to disconnection of the working line were prevented.

[Problem to be solved by the invention]

The conventional remote monitoring and control system described above requires two dedicated lines: a working line that is always used between the master station and the slave stations, and a protection line that is used in the event of a failure of the working line.
The disadvantage is that communication costs for lines are required.

An object of the present invention is to provide a remote monitoring and control system in which communication costs are reduced by using only a working line as a dedicated line and using a public telephone line as a protection line.

[Means to solve the problem]

In the remote monitoring and control system of the present invention, the monitoring and control station automatically calls and calls all monitored control stations via a public telephone line, sends a connection instruction signal, and then calls the public telephone line. It has a public telephone line automatic call connection circuit that connects to the supervisory control device and receives a recovery instruction signal, sends the recovery signal to all monitored control stations via the public telephone line, and puts the public telephone line on-hook. , each monitored control station automatically responds to a public telephone line when an incoming call is received on the public telephone line, connects the public telephone line to the monitored control device when it receives a connection instruction signal, and when it receives a recovery signal. It has a public telephone line connection circuit that puts the public telephone line on-hook.

[For production]

When the current monitoring and control line becomes faulty, the master station uses the public telephone line automatic call connection circuit to call all the slave stations and sends a connection instruction signal, and then monitors the public telephone line via the active/standby switching circuit. After each slave station is called on the public telephone line and receives a connection instruction signal, it connects the public telephone line to the monitored control device via the working/standby switching circuit. The line can be used as a backup line for a remote monitoring and control system.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the remote monitoring and control system of the present invention.

This remote monitoring and control system consists of a master station 1 and slave stations 2I, 2□
, ~, 2o, and has a dedicated line 7, and all stations are connected to the public telephone network 8.
has joined. The master station 1 has a public telephone line 8°, a supervisory control device (not shown), a working/protection line switching circuit 3, and a public telephone line automatic origination connection circuit 4. The working/protection line switching circuit 3 switches and connects the monitoring and controlling device to either the working line or the protection line in response to an instruction signal from the monitoring and controlling device (not shown). The public telephone line automatic call connection circuit 4 is activated when the working/protection line switching circuit 3 is switched to the protection side.
All preset slave stations are automatically dialed and called via the public telephone line 8°, a connection instruction signal is sent, and then the public telephone line 8° is connected to the backup side of the working/protection line switching circuit 3. Thereafter, upon receiving the restoration instruction signal from the supervisory control device, the restoration signal is sent to each of the slave stations 21, 2□, . The slave stations 21, 22, . . . , 2n are each monitored control station W.
(not shown), public telephone lines 8, 98□, ~, 8o,
Working/protection line switching circuits 5□, 5°, . . . , 5o and public telephone line connection circuits 6, . 62. ~． It has 6o.

The public telephone line connection circuits 60, 6□, -, 6n are connected to the public telephone line 8. ．． 82. ~, 8n automatically responds when an incoming call is received, and upon receiving a connection instruction signal, switches to the working/line side and connects to the public telephone line 83.8□.

~, 8n as the working/protection line switching circuit 5. ．． 52°~, 5
Connect to the protection line side of n, and when the recovery signal is received, the working/
Protection line switching circuit 5. ．． 52. -5o is restored, and public telephone lines 8, 8□, and -8o are placed on-hook. Each public telephone line 8o, 8. , 8□, -, 8n are subscriber telephone lines connected to the public telephone network.

Next, the operation of this embodiment will be explained.

When the dedicated line 7, which is the working line, becomes impaired, the master station 1 switches the working/protection line switching circuit 3 to the protection line side. This switching activates the public telephone line automatic calling connection circuit 4, and all slave stations 2□, 22. ~2o is automatically dialed and a connection instruction signal is issued. Each slave station 2. , 22. ~, 2n are public telephone lines 81, 8°, ~, 8, respectively. ．． When there is an incoming call, the public telephone line connection circuits 61, 62 . ~, 6o starts,
When it automatically responds and receives a connection instruction signal, it switches to the current line and connects to the public telephone line 8. ．． 82° to 8o are connected to a monitored control device (not shown). In this way, all slave stations 2.
．． 22. ~, 2° is connected to a supervisory control device (not shown) of the master station 1 via a public telephone line. After that, dedicated line 7
When the fault is recovered and the maintenance person restores the working/protection line switching circuit 3 of the master station 1 to the working line side, a recovery signal is sent from the public telephone line automatic call connection circuit 4. Each slave station 2□
, 2□, -, 2n are public telephone line connection circuits 63, 6□ upon receiving the recovery signal.

. . . , 6o are working/protection line switching circuits 53, 5□.

～, 5o restored and public telephone line 8□, 82°～, 8n
is on-hook.

〔Effect of the invention〕

As explained above, the present invention uses one dedicated line between the master station and the slave station, and in the event of a failure of the dedicated line, the system switches to the public telephone line, so that only one dedicated line is required. In addition, the public telephone line used as a backup line is only used when the dedicated line is out of order, which has the great effect of reducing communication costs.

4,

[Brief explanation of drawings]

Figure 1 shows One of the remote monitoring and control systems of the present invention FIG. 2 is a block diagram of an embodiment. ·master station, 2゜ 2 2゜ ·Slave station, ・Public phone line automatic call connection circuit, ・Dedicated line, ・Public phone network, 8゜ 1 2 8゜ Public phone line.

Claims (1)

[Claims] 1. In a remote supervisory control system in which one supervisory control station and at least one monitored control station are connected via one dedicated line, and remote supervisory control is performed by sending and receiving supervisory/control data. , The supervisory control station automatically calls and calls all monitored control stations via the public telephone line, sends a connection instruction signal, and then connects the public telephone line to the supervisory control device and restores the system. Upon receiving the instruction signal, the system has a public telephone line automatic call connection circuit that sends a recovery signal to all monitored control stations via the public telephone line and puts the public telephone line on-hook, and each monitored control station A public telephone line, and automatically answers when there is an incoming call on the public telephone line, connects the public telephone line to the monitored control device when a connection instruction signal is received, and puts the public telephone line on-hook when a recovery signal is received. A remote monitoring and control system characterized by having a public telephone line connection circuit.