JPH07327062A - Communication control method - Google Patents

Abstract

PURPOSE:To provide a method not requiring to restore the state of a transmission control procedure to the initial state and to make the transmission procedure control section in duplicate even in the case of line changeover when the communication lines are made in duplicate in the communication control method by the transmission control procedure making error correction. CONSTITUTION:A controller 2 is provided with a branching device 10 branching outgoing lines 14, 16 and a selector switch 12 selecting either of incoming lines 13, 15. A controlled device 1 is provided with a branching device 9 branching the incoming lines 13, 15 and a selector switch 11 selecting either of the outgoing lines 14, 16. For example, when a fault takes place in the incoming line 13, the line 13 is switched to the incoming line 15 by the selector switch 12 and the controller 2 and the controlled device 1 are communicated. Thus, in the case of line switching, it is not required to restore the state of the transmission control procedure to the initial state and it is not required to make the transmission procedure control sections 3, 4 in duplicate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control method in a communication system in which a control device and a controlled device which are installed remotely are connected by a communication line to transmit information, and more particularly, a communication line is duplicated for communication. The present invention relates to a communication control method for performing the communication.

[0002]

2. Description of the Related Art In information transmission via a communication line, a transmission error may occur on the receiving side due to noise on the transmission line, and if this is detected, it is possible to request the transmitting side to resend the same information. It is common to use a transmission control procedure such as a procedure (high-level data link control procedure). The HDLC procedure is JIS X5104, 5105.
And 5106 is a procedure characterized by code-independent and high-efficiency transmissions. In this case, a pair of a communication line for transmitting information and a communication line for receiving information is connected to one transmission control unit on the control device side and one transmission control unit on the controlled device side.

As a conventional example of the above-mentioned communication control method, there is a communication system as disclosed in, for example, Japanese Patent Laid-Open No. 2-67853, and its configuration is shown in FIG. In FIG. 5, 1 is a controlled device, 24 is an upper control device, 25 is a lower control device, 30, 31, 32 are master transmission procedure control units, 5, 6, 28 are modulators, 7, 8, 29 are demodulations. Bowl, 1
1 is a selection switch for the upper control device 24 and the lower control device 25, 9 is a branching device for branching the transmission data of the controlled device 1, 34 and 35 are reception-only slave transmission units of the upper control device 24 and the lower control device 25, Reference numeral 33 is a transmission-only slave transmission section of the controlled device 1, and 12, 26 and 27 are selection switches for switching between data transmission / reception by the master transmission procedure control sections 30-32 or slave transmission sections 33-35, 13, 15 Is an uplink and 14 and 16 are downlinks.

Next, the operation of this conventional example will be described. The upstream signal from the modulator 5 of the controlled device 1 is branched by the branching device 9 of the lower control device 25, and the upper control device 24
Are demodulated by the demodulator 8 and the demodulator 29 of the lower controller 25. The demodulated data is the master transmission procedure control unit 31 or the master transmission procedure control unit 32 in the upper control device 24 or the lower control device 25 which controls the downlink data.
In other control devices that do not control downlink data, the data is input to the slave transmission unit. In the control device that controls the downlink data, the downlink data of the master transmission procedure control unit 31 or the master transmission procedure control unit 32 is the selection switch 1
Since it is in the connection state at 1, the data is input to the master transmission procedure control unit 30 of the controlled device 1. Therefore, the control device controlling the downlink data and the controlled device 1 can communicate with each other using a transmission control procedure capable of retransmission when a transmission error occurs. The control device that does not control the downlink data can monitor the uplink data only in the communication between the other control device and the controlled device 1 when no transmission error occurs.

As a conventional example of a communication control method different from the above, there is a method of duplicating a communication line, and the configuration of this method is shown in FIG. In FIG. 6, 1 is a controlled device, 2 is a control device, 3, 4, 36 are transmission procedure control units, 5, 6, 2
Reference numeral 7 is a modulator, 7, 8 and 28 are demodulators, 9 is a branching device for transmitting signals of the modulator 5, 11 is a selector switch for receiving signals from the modulator 6 or the modulator 27 of the controller 2, and 12 is control. This is a selection switch for switching which of the transmission procedure control unit 4 and the transmission procedure control unit 36 in the device 2 performs data transmission and reception.

Next, the operation of this conventional example will be described. The upstream signal from the modulator 5 of the controlled device 1 is branched by the branching device 9, and the upstream line 13 of the duplexed communication line,
15 to the demodulator 8 and the demodulator 2 of the control device 2.
Receive at 8. In the control device 2, either the transmission procedure control unit 4 or the transmission procedure control unit 36 is selected by the selection switch 12, and the selected transmission procedure control unit sends a response to the downlink via the modulator 6 or the modulator 27. 14 or downlink 16. In the controlled device 1, the selection switch 11 selects the downlink 14 or the downlink 16, and connects to the demodulator 7. As described above, when the uplink 13 and the downlink 14 are used, the transmission procedure controller 3 of the controlled device 1 and the transmission procedure controller 4 of the controller 2 transmit and receive data, and the uplink 15 and the downlink 16 are connected. When used, the transmission procedure control unit 3 of the controlled device 1 and the transmission procedure control unit 36 of the control device 2 send and receive data.

[0007]

Since the conventional communication control method is configured as described above, when the communication line is switched, the connected transmission procedure controller is also switched.
Return the state of the transmission control procedure before switching to the initial state,
Since communication is continued after that, the communication was temporarily interrupted. Further, when the communication line is duplicated so that the other communication line can be used when one communication line fails, it is necessary to duplicate the transmission procedure control unit of the control device.

The present invention has been made in order to solve the above problems, and when the communication line is duplicated,
An object of the present invention is to provide a communication control method in which it is not necessary to return the state of the transmission control procedure to the initial state even when the line is switched, and the transmission procedure control unit of the control device need not be duplicated.

[0009]

According to a first aspect of the present invention, in a communication system, first and second upstream lines as at least two dedicated communication lines for performing communication from a controlled device to a control device, The control device and the controlled device are connected to each other by the first and second downlinks as at least two dedicated communication lines for performing communication from the control device to the controlled device, and the control device is connected to the control device. A control side branching unit for branching the first and second downlinks;
A control side selecting means for selecting one of the second uplinks, and a controlled side branching means for branching the first and second uplinks to the controlled device; Controlled side selecting means for selecting any one of the downlink lines.

According to a second aspect of the present invention, in a communication system, at least one dedicated communication line for communicating from the controlled device to the control device, and communication from the control device to the controlled device are provided. At least one to do
Downlink as one dedicated communication line, the control device and the controlled device are connected by a circuit switching network, the control side branching means for branching the downlink and the circuit switching network to the control device, A control side selecting means for selecting either the uplink or the circuit switched network, and a controlled side branch means for branching the uplink or the circuit switched network to the controlled device; and the downlink. And a controlled side selecting means for selecting any one of the circuit switching networks.

According to a third aspect of the invention, the control device and the controlled device are connected by at least two first and second lines as dedicated communication lines for communicating between the control device and the controlled device. Then, control side branching means for branching the transmission signal to the control device and branching the transmission signal to the first and second lines, and control side selection for selecting one of the reception signals from the first and second lines. Means for branching a transmission signal to the controlled device for branching the transmission signal to the first and second lines, and one of the reception signals from the first and second lines. And a controlled side selecting means for selecting.

According to a fourth aspect of the present invention, any one of control side branching means for branching a transmission signal to a control device and giving it to a dedicated communication line and a circuit switching network, and a reception signal from the dedicated communication line and the circuit switching network. A control side selecting means for selecting, and a controlled side branching means for branching a transmission signal to the controlled device and giving it to the dedicated communication line and the circuit switching network,
Controlled-side selecting means for selecting either the dedicated communication line or the received signal from the circuit switching network.

[0013]

According to the first aspect of the present invention, for example, when a failure occurs in the first uplink, the control side selecting means switches to the second uplink and a failure occurs in the first downlink. In this case, the controlled side selecting means switches to the second downlink, which enables communication between the control device and the controlled device.

According to the second aspect of the present invention, for example, when a failure occurs in the circuit switching network, the control side selecting means switches to the uplink, and when a failure occurs in the downlink,
The controlled-side selecting means switches to the circuit switching network, which enables communication between the control device and the controlled device.

According to the third aspect of the invention, for example, when a failure occurs in the first line, the control side selection means and the controlled side selection means switch to the reception signal from the second line, whereby the control device is provided. Is capable of receiving a signal from the controlled device.

According to the fourth aspect of the invention, for example, when a failure occurs in the dedicated communication line, the control side selecting means and the controlled side selecting means switch to the circuit switching network, whereby the control device and the controlled device are connected. Communication becomes possible.

[0017]

【Example】

Example 1 (corresponding to claim 1). Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a communication system that employs the communication control method according to the first embodiment of the present invention. In FIG. 1, reference numeral 2 denotes a control device such as a host computer, 1 denotes a controlled device controlled by the control device 2, and the control device 2 and the controlled device 1 are arranged remote from each other. The controlled device 1 branches the output of the transmission procedure control unit 3 that controls the transmission procedure of the signal, the modulator 5 that modulates the signal to be transmitted, the demodulator 7 that demodulates the received signal, and the modulator 5 before going up. A branching device 9 connected to the line 13 and the up line 15, and a selection switch 11 for selecting the down line 14 or the down line 16 and connecting to the demodulator 7.
Is equipped with. The control device 2 includes a transmission procedure control unit 4 that controls a signal transmission procedure, a modulator 6 that modulates a signal to be transmitted, a demodulator 8 that demodulates a received signal, and an output of the modulator 6 to branch to a downlink. 14 and the branching device 10 connected to the downlink 16 and the selection switch 12 for selecting the uplink 13 or the uplink 15 and connecting to the demodulator 8.

In the communication control method according to the first embodiment, the uplinks 13 and 15 for communicating from the controlled device 1 to the control device 2 and the communication from the control device 2 to the controlled device 1 are used. The control device 2 and the controlled device 1 are connected by the downlinks 14 and 16, and the control device 2 is connected to the downlink 1
Branching device 1 as branching means on control side for branching 4, 16
0 and a selection switch 12 as a control side selecting means for selecting either the up line 13 or 16, and a branching device as a controlled side branching device for branching the up line 13 or 15 to the controlled device 1. 9 and a selection switch 11 as controlled side selection means for selecting one of the downlinks 14 and 16, and when a line failure occurs in any of the uplinks 13 and 15, the selection switch 12 detects the failure. It is characterized in that switching is performed from the uplink to the normal uplink, and when a line failure occurs in any of the downlinks 14 and 16, the selection switch 11 performs control to switch the failed downlink to the normal downlink.

Next, the operation of the first embodiment will be described.
In the configuration of FIG. 1, in the controlled device 1, the output signal from the transmission procedure control unit 3 is modulated by the modulator 5, and the signal branched by the branching device 9 is transmitted to the uplink 13 and the uplink 15. In the control device 2, one of the uplink 13 and the uplink 15 is selected by the selection switch 12, the received signal is demodulated by the demodulator 8, and then input to the transmission procedure controller 4.
The transmission procedure control unit 4 performs an error check on the received data, and sends a response signal when the data is normally received, or a resend request signal when an error is detected, and sends a downlink signal to the controlled device 1.
Alternatively, the data is transmitted using the downlink 16. In the controlled device 1, similarly, either the downlink 14 or the downlink 16 is selected by the selection switch 11, the received signal is demodulated by the demodulator 7, and is input to the transmission procedure control unit 3.

An operation when a line disconnection occurs in the up line 13 as an example of the line failure when the up line 13 is selected by the selection switch 12 of the control device 2 will be described below.
When a line disconnection occurs in the uplink 13 at the timing when the controlled device 1 is not transmitting data, the demodulator 8 detects this and the selection switch 12 switches the line to the uplink 15 side. In this case, since data does not flow on the line in either the up or down direction, there is no change in the transmission procedure of the transmission procedure control units 3 and 4, and when the next transmission data occurs, the previous transmission procedure is changed. Communication can be continued.

Further, if a line disconnection occurs in the up line 13 at the timing of transmitting data from the controlled device 1, the demodulator 8 detects this and the selection switch 12 switches the line to the up line 15 side. Switch to. in this case,
Although the same data is flowing in the upstream line 15, there may be a difference in transmission delay time or a momentary interruption due to the selection switch 12. When the transmission procedure control unit 4 detects a transmission error, the control device 2 transmits a retransmission request signal to the controlled device 1. However, the transmission procedure control units 3 and 4 operate as if an ordinary transmission error occurred. There is no need to return the transmission control procedure to the initial state.

Embodiment 2 (corresponding to claim 2). FIG. 2 is a block diagram showing the configuration of a communication system that employs the communication control method according to the second embodiment of the present invention. 2, components corresponding to those shown in FIG. 1 are designated by the same reference numerals, and their description will be omitted. In FIG. 2, 19 is a circuit switching network that connects the control device 2 and the controlled device 1, 17 is a network control device that is provided in the controlled device 1 and that controls connection to the circuit switching network 19, and 18 is the control device 2. Is equipped with a circuit switching network 19
A network control device that controls connection to the network.

In the communication control method according to the second embodiment, the uplink 13 as a dedicated communication line for performing communication from the controlled device 1 to the control device 2 and the communication from the control device 2 to the controlled device 1 are performed. A control side that connects the control device 2 and the controlled device 1 by a downlink 14 as a dedicated communication line for performing the operation and a circuit switching network 19 and branches the downlink 14 and the circuit switching network 19 to the control device 2. The controlled device 1 is provided with a branching device 10 as a branching device and a selection switch 12 as a control side selecting device for selecting one of the uplink 13 and the circuit switching network 19. A branching device 9 as a controlled side branching means for branching the network, and a selection switch 11 as a controlled side selecting means for selecting either the downlink 14 or the circuit switching network 19, and the uplink 13 and the circuit switching. If a line failure occurs in any one of 19, the selection switch 12 switches the failed line to a normal line, and if a line failure occurs in any of the downlink 14 and the circuit switching network 19, a failure occurs by the selection switch 11. It is characterized in that control is performed to switch from the normal line to the normal line.

Next, the operation of the second embodiment will be described.
In the configuration of FIG. 2, the controlled device 1 and the control device 2 normally communicate with each other through an up line 13 and a down line 14 as dedicated communication lines, and if any one of them fails, the line is switched. Connect the network 19 and switch to it.
In the controlled device 1, the output signal from the transmission procedure control unit 3 is modulated by the modulator 5, and the signal branched by the branching device 9 is transmitted to the uplink 13. In the control device 2, normally, the upstream line 13 is selected by the selection switch 12, the signal transmitted from the upstream line 13 is demodulated by the demodulator 8, and then input to the transmission procedure control unit 4. The transmission procedure control unit 4 performs an error test on the received data, and outputs a response signal when the data is normally received or a retransmission request signal when an error is detected.
To be transmitted using the downlink 14. In the controlled device 1, normally, the selection switch 11 selects the downlink 14, the signal transmitted from the downlink 14 is demodulated by the demodulator 7, and is input to the transmission procedure controller 3.

When the control device 2 selects the up line 13 with the selection switch 12, an operation when a line break occurs in the up line 13 as an example of a line failure will be shown below.
When a line disconnection occurs in the up line 13 at the timing when the controlled device 1 does not transmit data, the demodulator 8 detects this and switches to the network control device 18 by the selection switch 12, and the network control device 17, The line between 18 is connected. The line control operates in this way, but since no data flows on the line in either the up or down direction, there is no change in the transmission procedure of the transmission procedure control unit 3 and the transmission procedure control unit 4, and the next transmission is performed. If data occurs, communication can continue following the previous transmission procedure.

When a line disconnection occurs in the up line 13 at the timing of transmitting data from the controlled device 1, the demodulator 8 detects this and the selection switch 12 causes the network control device 18 to operate in the same manner as above. Switch, connect the line. In this case, the control device 2 detects a transmission error in the transmission procedure control unit 4 and transmits a retransmission request signal to the controlled device 1, but the transmission procedure control units 3 and 4 operate when a normal transmission error occurs. There is no need to return the transmission control procedure to the initial state.

Embodiment 3 (corresponding to claim 3). FIG. 3 is a block diagram showing the configuration of a communication system that employs the communication control method according to the third embodiment of the present invention. In FIG. 3, components corresponding to those shown in FIG. 1 are designated by the same reference numerals, and their description will be omitted. In FIG. 3, 20 is a controlled device 1
And a modulator / demodulator 21 for modulating a signal transmitted to the first line 13a and demodulating a signal transmitted from the first line 13a. To modulate the signal transmitted to the line 14a of
It is a modulator / demodulator that demodulates the signal transmitted from the second line 14a. Reference numeral 22 denotes a modulator / demodulator provided in the control device 2 for modulating a signal transmitted to the first line 13a and demodulating a signal transmitted from the first line 13a. And modulates the signal transmitted to the second line 14a or the second line 14a.
It is a modulator / demodulator that demodulates the signal transmitted from the.

In the communication control method according to the third embodiment, the control device 2 and the control device 2 are controlled by the first and second lines 13a and 14a as dedicated communication lines for performing communication between the control device 2 and the controlled device 1. The control devices 1 are connected to each other, and the control device 2 branches the transmission signal to the first and second lines 13a and 14a to serve as control side branching means 10 and the first and second lines 13a. , 14a, and a selection switch 12 as a control side selecting means for selecting one of the received signals from the control signals, and the controlled device 1 branches the transmission signal and supplies it to the first and second lines 13a, 14a. The branching device 9 as the control side branching means and the selection switch 11 as the controlled side selecting means for selecting one of the reception signals from the first and second lines 13a and 14a are provided. Line 13a, 1
When a line failure occurs in any of 4a, the selection switch 12 or the selection switch 11 is controlled to switch to a reception signal from a normal line.

Next, the operation of the third embodiment will be described.
In the configuration of FIG. 3, in the controlled device 1, the output signal from the transmission procedure control unit 3 is branched by the branching device 9, and the modulator / demodulator 2
The transmission signals are 0 and 21. In the control device 2, the modulator / demodulator 2
The reception data 2 and 23 are selected by the selection switch 12 and input to the transmission procedure controller 4. The transmission procedure control unit 4 performs an error test on the received data, and sends a response signal in the case of normal reception or a resend request signal in the case of detecting an error to the controlled device 1 which is a duplicated communication line. Line 13
a and the second line 14a. Similarly, in the controlled device 1, one of the data received from the modulators / demodulators 20 and 21 is selected by the selection switch 11 and input to the transmission procedure controller 3.

When the modulation / demodulator 20 is selected by the selection switch 11 of the controlled device 1 and the modulation / demodulation device 22 is selected by the selection switch 12 of the control device 2, the line disconnection is the first line as an example of the line failure. The operation when it occurs in 13a is shown below. When a line disconnection occurs in the first line 13a at the timing when the controlled device 1 is not transmitting data, the modem unit 22 detects this and switches the selection switch 12 to the modem unit 23 side. Also in the controlled device 1, the modem 20 detects the line disconnection and switches the selection switch 11 to the modem 21 side. In this case, since no data flows on the line in either the up or down direction, the transmission procedure control unit 3,
There is no change in the transmission procedure of No. 4, and when the transmission data is generated next, the communication can be continued after the previous transmission procedure.

Further, when a disconnection occurs in the first line 13a at the timing of transmitting data from the controlled device 1, similarly, the selection switch 12 is placed on the side of the modulator / demodulator 23 and the selection switch 11 is placed on the side of the modulator / demodulator 21. Switch to the side. In this case, although the same data is flowing through the second line 14a, there may be a difference in transmission delay time or a momentary interruption due to the selection switches 11 and 12. When the transmission procedure control unit 4 detects a transmission error, the control device 2 transmits a retransmission request signal to the controlled device 1. However, the transmission procedure control units 3 and 4 operate as if an ordinary transmission error occurred. There is no change, and in this case it is not necessary to return the transmission control procedure to the initial state.

Embodiment 4 (corresponding to claim 4). FIG. 4 is a block diagram showing the configuration of a communication system that employs the communication control method according to the fourth embodiment of the present invention. 4, the components corresponding to those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 4, the network control device 17 in the controlled device 1 is provided between the modulator / demodulator 21 and the circuit switching network 19, and is controlled by the transmission procedure control unit 3. The network control device 18 in the control device 2 includes a modulator / demodulator 23 and a circuit switching network 1
9, and the transmission procedure is controlled by the control unit 4.

In the communication control method according to the fourth embodiment, a branching device 10 as a branching means on the control side for branching a transmission signal to the control device 2 and giving it to the dedicated communication line 13b and the circuit switching network 19, and a dedicated communication line. 13b and circuit switching network 1
And a selection switch 12 as control side selection means for selecting any one of the reception signals from the control signals from the control signals to the controlled device 1 and branching the transmission signals to the dedicated communication line 13b and the circuit switching network 19. A branching device 9 as a branching means,
A selection switch 11 is provided as a controlled side selecting means for selecting one of the received signals from the dedicated communication line 13b and the circuit switching network 19, and a line failure occurs in either the dedicated communication line 13b or the circuit switching network 19. In that case, the selection switch 12 and the selection switch 11 are characterized by performing control to switch to a reception signal from a normal line.

Next, the operation of the fourth embodiment will be described.
In the configuration of FIG. 4, the controlled device 1 and the control device 2 normally communicate with each other through the dedicated communication line 13b, and when a line failure occurs, the circuit switching network 19 is connected and switched to this. In the controlled device 1, the output signal from the transmission procedure control unit 3 is branched by the branching device 9 and becomes a transmission signal of the modulators / demodulators 20 and 21. In the control device 2, normally, the received data from the modulator / demodulator 22 is selected by the selection switch 12 and input to the transmission procedure control unit 4. The transmission procedure control unit 4 performs an error test on the received data, and outputs a response signal when the data is normally received, or a retransmission request signal when an error is detected, and the controlled device 1
Is transmitted using the dedicated communication line 13b. Controlled device 1
Then, similarly, normally, the received data from the modulator / demodulator 20 is selected by the selection switch 11 and input to the transmission procedure control unit 3.

When the modulator / demodulator 20 is selected by the selection switch 11 of the controlled device 1 and the modulator / demodulator 22 is selected by the selection switch 12 of the control device 2, a line disconnection is an example of the line communication as the dedicated communication line 13b. The operation when it occurs in is shown below. When a line disconnection occurs in the dedicated communication line 13b at the timing when the controlled device 1 is not transmitting data, the modem unit 22 detects this and switches the selection switch 12 to the modem unit 23 side, and at the same time, the network controller 1
The line of the circuit switching network 19 between 7 and 18 is connected. Also,
Also in the controlled device 1, the modem disconnection is detected by the modem 20 and the selection switch 11 is switched to the modem 21 side. In this case, since data does not flow on the line in either the up or down direction, there is no change in the transmission procedure of the transmission procedure control units 3 and 4, and when the next transmission data occurs, the previous transmission procedure is changed. Communication can be continued.

If a line disconnection occurs in the dedicated communication line 13b at the timing when data is transmitted from the controlled device 1, similarly, the selection switch 12 is moved to the modulator / demodulator 23 side.
The selection switch 11 is switched to the modulator / demodulator 21 side to connect the line of the circuit switching network 19. In this case, the transmission procedure control unit 4 detects a transmission error and sends a retransmission request to the controlled device 1. However, the transmission procedure control units 3 and 4 perform the same operation as when a normal transmission error occurs, and It is not necessary to return the control procedure to the initial state.

As described above, according to Examples 1 to 4, 1
Since the transmission data from the transmission procedure control unit of each unit is transmitted to the duplicated communication line and one of the reception data from the duplicated communication line is selected and input to the transmission procedure control unit, the transmission procedure control unit etc. It can be configured with a stand, and an economical device configuration is possible. Further, in the case of a line failure, the device that detects this only switches the receiving line, so there is no need to return the transmission control procedure to the initial state, and the communication interruption time can be minimized.

According to the first embodiment, the modulator output is branched into two lines for transmission, and one of the received signals from the two lines is input to the demodulator. Therefore, all of the transmission procedure control section, modulator and demodulator Can be configured with one unit. Further, when a failure of one dedicated line is detected, the receiving line can be switched to the other dedicated line and the communication can be continued. Therefore, it is not necessary to return the transmission control procedure to the initial state, and the communication interruption time can be minimized.

According to the second embodiment, since the modulator output is branched into two lines for transmission and one of the received signals from the two lines is input to the demodulator, the transmission procedure control section, the modulator and the demodulator are All can be configured with one unit. Further, when the failure of the leased line is detected, the receiving line can be switched to the circuit switching network and the communication can be continued. Therefore, it is not necessary to return the transmission control procedure to the initial state, and the communication interruption time can be minimized.

According to the third embodiment, the output data of the transmission procedure control unit is branched into two and transmitted to the respective dedicated lines, and one of the received data from the two dedicated lines is input to the transmission procedure control unit. The procedure controller can be composed of one unit. Further, when the failure of one of the dedicated lines is detected, the received data can be switched to the other dedicated line and the communication can be continued. Therefore, it is not necessary to return the transmission control procedure to the initial state, and the interruption time of the communication can be minimized.

According to the fourth embodiment, since the output data of the transmission procedure control unit is branched into two, one is connected to the dedicated line and the other is connected to the circuit switching network, the transmission procedure control unit can be configured by one unit. Further, when a failure of the leased line is detected, the received data can be switched to the circuit switching network and the communication can be continued, so that it is not necessary to return the transmission control procedure to the initial state and the communication interruption time can be minimized.

[0042]

As described above, according to the first aspect of the present invention, a control system for performing a predetermined control and a controlled device controlled by the control system are connected by a dedicated communication line to perform communication. In the first and second uplinks as at least two dedicated communication lines for performing communication from the controlled device to the control device, and for performing communication from the control device to the controlled device. A control side that connects the control device and the controlled device by at least two first and second downlinks as dedicated communication lines, and branches the first and second downlinks to the control device. The control unit includes a branching unit and a control-side selecting unit that selects one of the first and second uplinks, and the controlled device is provided with the first and second units.
The controlled side branching means for branching the second uplink, and the controlled side selecting means for selecting one of the first and second downlinks are provided. If a line failure occurs in any of the above, the control side selecting means switches from the failed uplink to a normal uplink, and if any of the first and second downlinks causes a line failure, the controlled side is controlled. Since the side selection means controls the switching from the faulty downlink to the normal downlink, it is possible to configure the transmission procedure control unit and the like respectively provided in the control device and the controlled device by one unit, which is an economical device. In addition, it is possible to configure, and in the event of a line failure, the line can be switched from the faulty line to a normal line and communication can be continued, so there is no need to return the transmission control procedure to the initial state, and communication interruption time can be minimized. Say Results can be obtained.

According to the second aspect of the invention, in a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected to a dedicated communication line and a circuit switching network to perform communication, At least one dedicated communication line for communicating from the controlled device to the control device, and at least one dedicated communication line for communicating from the control device to the controlled device The control device and the controlled device are connected by a downlink and the circuit switching network, and control side branching means for branching the downlink and the circuit switching network to the control device; the uplink; Control side selecting means for selecting any one of the circuit switched networks, and controlled side branching means for branching the uplink and the circuit switched network to the controlled device,
The controlled side selecting means for selecting either the downlink or the circuit switched network is provided, and when a line failure occurs in either the uplink or the circuit switched network, the control side selecting means is used to Since the line is switched to the normal line, and if a line fault occurs in either the downlink or the line switching network, the controlled side selection means controls the switching from the faulty line to the normal line. , The control device and the controlled device can be configured with a single transmission procedure control unit, etc., which enables an economical device configuration. In the case of a line failure, the line can be normally switched from the failed line. Since the network can be switched over and the communication can be continued, there is no need to return the transmission control procedure to the initial state, and the effect of minimizing the communication interruption time can be obtained.

According to a third aspect of the present invention, in a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected by a dedicated communication line to perform communication, The control device and the controlled device are connected to each other by the first and second lines as at least two dedicated communication lines for performing communication between the controlled devices, and a transmission signal is branched to the control device. The above first,
Control side branching means for giving to the second line, and the first and second
Control side selecting means for selecting any one of the received signals from the line, the controlled side branching means for branching the transmission signal to the controlled device and giving it to the first and second lines, A controlled side selecting means for selecting one of the received signals from the first and second lines, and the controlling side selecting means when a line failure occurs in either of the first and second lines. Alternatively, since the control-side selecting means controls the switching to the received signal from the normal line, the transmission procedure control unit provided in each of the control device and the controlled device can be configured by one unit, which is an economical device. It is possible to configure, and when a line failure occurs, it is possible to switch to a received signal from a normal line and continue communication, so there is no need to return the transmission control procedure to the initial state, and communication interruption time can be minimized. Get the effect

According to the fourth aspect of the invention, in a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected to a dedicated communication line and a circuit switching network to perform communication, Control side branching means for branching a transmission signal to the control device and giving it to the dedicated communication line and the circuit switching network, and control side selection for selecting one of the reception signals from the dedicated communication line and the circuit switching network Means for branching a transmission signal to the controlled device to give the signal to the dedicated communication line and the circuit switching network, and any of the received signals from the dedicated communication line and the circuit switching network. And a controlled-side selecting means for selecting whether or not a line failure occurs in either the dedicated communication line or the circuit switching network, the control-side selecting means and the controlled-side selecting means. Since the signal received from the more normal line is switched, the transmission procedure control unit provided in each of the control device and the controlled device can be configured by one unit, and an economical device configuration can be achieved. Moreover, in the case of line failure Since it is possible to switch to a signal received from a normal line and continue communication, there is no need to return the transmission control procedure to the initial state, and the effect of minimizing the communication interruption time can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication system adopting a communication control method according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a communication system adopting a communication control method according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a communication system adopting a communication control method according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a communication system adopting a communication control method according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a communication system adopting a conventional communication control method.

FIG. 6 is a block diagram showing a configuration of a communication system adopting another conventional communication control method.

[Explanation of symbols]

1 controlled device, 2 control device, 3,4,36 transmission procedure control unit, 5,6,28 modulator, 7,8,29 demodulator, 9,10 branching device (controlled side branching means, control side branching unit) Means), 11, 12 selection switch (controlled side selection means, control side selection means), 13, 15 uplink (first and second uplink), 14 and 16 downlink (first, first)
Second downlink), 13a first line, 14a second line
Line, 13b dedicated communication line, 17,18 network control device, 19 circuit switching network, 20, 21, 22, 23 modulator / demodulator, 24 upper control device, 25 lower control device, 2
6, 27 selection switch, 30, 31, 32 master transmission procedure control unit, 33, 34, 35 slave transmission unit.

Claims (4)

[Claims] 1. In a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected by a dedicated communication line to perform communication, from the controlled device to the control device. First and second uplinks as at least two dedicated communication lines for communication,
The control device and the controlled device are connected to each other by the first and second downlinks as at least two dedicated communication lines for performing communication from the control device to the controlled device, and the control device is connected to the control device. A control side branching means for branching the first and second downlinks and a control side selecting means for selecting one of the first and second uplinks. The controlled side branching means for branching the first and second uplinks, and the controlled side selecting means for selecting one of the first and second downlinks, and the first and second uplinks If a line failure occurs in any of the above, the control side selecting means switches the failed uplink to a normal uplink, and if a line failure occurs in any of the first and second downlinks, the above is performed. Controlled-side selection means enables normal down Communication control method and performing control for switching the line. 2. A communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected to a dedicated communication line through a circuit switching network to perform communication, and the controlled device is connected to the controlled device. An uplink as at least one dedicated communication line for performing communication to the control device, a downlink as at least one dedicated communication line for performing communication from the control device to the controlled device, and the above line The control device and the controlled device are connected by a switching network, and any one of the control side branching unit for branching the downlink and the circuit switching network to the control device, the uplink and the circuit switching network. Control side selecting means for selecting the control side selecting means for branching the uplink and the circuit switched network, and the downlink and the circuit switched network to the controlled device. When a line failure occurs in either the above-mentioned uplink or the above-mentioned circuit switching network, the controlled side selecting means is used to switch from the failed line to a normal line, A communication control method characterized in that, when a line failure occurs in any of the circuit switching networks, the controlled side selecting means performs control to switch from the failed line to a normal line. 3. In a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected by a dedicated communication line to perform communication, between the control device and the controlled device. At least two for communicating
A control side in which the control device and the controlled device are connected by first and second lines as one dedicated communication line, and a transmission signal is branched to the control device and is given to the first and second lines. A branching means and a control side selecting means for selecting one of the reception signals from the first and second lines are provided, and the transmission signal is branched to the controlled device to divide the first and second lines. To the controlled side branching means and controlled side selecting means for selecting one of the received signals from the first and second lines, and the line failure in any of the first and second lines. When the above occurs, the communication control method is characterized in that the control side selecting means and the controlled side selecting means perform control to switch to a reception signal from a normal line. 4. In a communication system in which a control device for performing a predetermined control and a controlled device controlled by the control device are connected to a dedicated communication line by a circuit switching network to perform communication, the control device transmits to the control device. Control side branching means for branching a signal and giving it to the dedicated communication line and the circuit switching network,
The control side selecting means for selecting either the dedicated communication line or the received signal from the circuit switching network is provided, and the transmission signal is branched to the controlled device and given to the dedicated communication line and the circuit switching network. The controlled-side branching means and the controlled-side selecting means for selecting one of the received signals from the dedicated communication line and the circuit switching network are provided, and a line failure occurs in either the dedicated communication line or the circuit switching network. When the above occurs, the communication control method is characterized in that the control side selecting means and the controlled side selecting means perform control to switch to a reception signal from a normal line.