JP2006086914A - Remote monitoring control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exactly confirm generation of an abnormality when level deterioration of a carrier signal is generated. <P>SOLUTION: In a remote monitoring control system where between a master station 1 and a slave station 2 is connected by doubleness transmission paths A, B up and down, respectively, a carrier signal of transmitted information is branched with turnouts 3S, 4S, transmitted by the redundant transmission paths, received by switching it to one of the redundant transmission paths by switches 3R, 4R and switches switch receiving output to the other receiving output when the level deterioration of the received signal continues for time set by timer time limits of monitoring timers 3T, 4T, test wave generators 3C, 4C periodically inject test wave signals to the turnouts, transmit them by the redundant transmission path and switch discriminators 3J, 4J automatically compensate time difference of a received pair of test wave signals as a timer limit of the monitoring timer. Display units 3D, 4D display the time difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a remote monitoring control system in which a master station and a slave station are connected by a duplex transmission path, and more particularly to a transmission path switching system.

  An example of the configuration of this type of remote monitoring control system is shown in FIG. The control station 1 serving as a master station and the controlled station 2 serving as a slave station are connected via switching circuits 3 and 4 through duplex transmission paths (upstream transmission paths A and B and downstream transmission paths A and B).

  The controlled station 2 modulates the upstream information output from the information processing device (CPU) 2SC by the modulator 2M and outputs it to the switching circuit 4 as a carrier signal. The signal is branched by the branching unit 4S of the switching circuit 4. Are transmitted through the duplex transmission paths A and B. The switching circuit 3 selects only one of the carrier signals transmitted through the duplex transmission paths A and B with the switch 3R, and this carrier signal is demodulated by the demodulator 1D of the control station 1 to obtain an information processing device (CPU) 1RC. Receive processing.

  Similarly, the control station 1 modulates the downlink information output from the information processing device (CPU) 1SC by the modulator 1M and outputs it as a carrier signal to the switching circuit 3, and this signal is output by the branching unit 3S of the switching circuit 3. Branch and transmit on the duplex transmission lines A and B. The switching circuit 4 selects only one of the carrier signals transmitted through the duplex transmission paths A and B with the switch 4R, and this carrier signal is demodulated by the demodulator 2D of the controlled station 2 to be processed by an information processing device (CPU). Receive processing at 2RC.

  Here, in the transmission path switching control by the switching units 3R and 4R of the switching circuits 3 and 4, the magnitude of the carrier signal (incoming call level) output from the currently used transmission path (used transmission path) to the demodulator. ) Is monitored, and when the incoming signal level is lower than the set value, switching to the standby transmission line is performed on the condition that the incoming level of the carrier signal from the standby transmission line is healthy (see, for example, Patent Document 1).

  As shown in the time chart of FIG. 3, the above transmission path switching is performed when the carrier signal level from the used transmission path A decreases (when an abnormality occurs), and abnormality occurrence confirmation timers 3T and 4T shown in FIG. Continuation of the occurrence of the abnormality is confirmed only for the timer period set to, and the abnormality is notified by this confirmation, and the switch is switched to the standby transmission path B side. In this switching, the signal being switched is notified to the information processing apparatus on the receiving side, and the information processing apparatus on the receiving side secures a switching time for performing processing such as signal discard and resumption of reception of the current carrier signal.

As a communication method in the remote monitoring control system, an HDLC (High Level Data Link Control) method suitable for high-speed data transmission is widely used instead of the conventional cyclic transmission method.
JP 2003-134002 A

  The timer time limit in the remote monitoring control system is set to about several seconds and reliably detects a decrease in signal level. Setting the timer time limit has a problem that when the signal level actually decreases, switching is delayed by that amount, and transmission / reception information is lost in proportion to the delay time.

  Conversely, if the timer time is set short, the synchronization signal included in the output of the modulator and demodulator may have a time when there is no energy. Therefore, unnecessary switching of the transmission route is performed. This switching has a problem in that the logical coupling of the transmission path is interrupted during route switching, and transmission / reception information is lost.

  An object of the present invention is to provide a remote monitoring and control system that can accurately check the occurrence of an abnormality when a decrease in the level of a carrier signal occurs.

  In order to solve the above-mentioned problem, the present invention sets the timer period of the monitoring timer for confirming the occurrence of abnormality in the duration when the level drop occurs in the carrier signal, and the same test wave signal to each of the duplex transmission lines. Injected and automatically corrected in accordance with the time difference when these pairs of test wave signals are transmitted to the switch, and has the following configuration.

(1) The master station and slave stations are connected by a duplex transmission line, the transmission side branches the carrier signal of transmission information by a branching device and transmits it by the duplexing transmission line, and the reception side has one of the duplex transmission lines by a switch. A remote monitoring control system comprising a transmission line switching means for switching to a reception output from the other transmission line when a decrease in the level of the received signal continues for a time set by the timer time limit of the monitoring timer. In
The transmission side is provided with a test wave signal transmitting means for periodically injecting a test wave signal into the branching device and transmitting it by the duplex transmission line,
The receiving side is provided with a switching determination means for detecting a time difference between a pair of test wave signals received on the duplex transmission path and automatically correcting the time difference as a timer time limit of the monitoring timer.

  (2) The switching determination means includes means for displaying the time difference on a display.

  As described above, according to the present invention, when the level drop occurs in the carrier signal, the timer period of the monitoring timer for confirming the occurrence of abnormality in the duration is injected, and the same test wave signal is injected into the duplex transmission path. In addition, since these pairs of test wave signals are automatically corrected according to the time difference when they are transmitted to the switch, it is possible to obtain an accurate confirmation as compared with the confirmation of the occurrence of an abnormality due to the level reduction duration. .

  For example, it is possible to set a timer time limit that clearly discriminates between an actual transmission abnormality and a change in transmission path characteristics, and shortens a switching delay when a transmission abnormality occurs.

  Further, even when there is no energy in the synchronization signal included in the outputs of the modulator and demodulator, erroneous detection can be prevented, and unnecessary switching of transmission routes can be eliminated.

  In addition, the time difference of the test wave signal can be displayed on a numeric display, which can be used to promote recognition and improvement of the current state of transmission characteristics.

  FIG. 1 is a system configuration diagram showing an embodiment of the present invention. 2 is different from FIG. 2 in that test wave generators 3C and 4C, synthesizers (hybrid transformers) 3H and 4H, switching determination units 3J and 4J, and number indicators 3D and 4D are provided.

  The test wave generators 3C and 4C periodically generate test wave signals (pulse signals having test wave codes) having the same frequency and level as the carrier signals generated by the modulators 1M and 2M. The combiners 3H and 4H combine the carrier signals from the modulators 1M and 2M and the test waves generated by the test wave generators 3C and 4C, and output them as input signals to the branching units 3S and 4S.

  The switching determination units 3J and 4J are transmitted through the duplex transmission paths A and B, and among the signals input to the switching units 3R and 4R, the pair of test waves generated and branched by the test wave generators 3C and 4C. Are extracted, the time difference between the two test wave signals is detected, the time limit of the abnormality occurrence confirmation timers 3T, 4T is automatically corrected according to the time difference, and the time difference is displayed on the numeric indicators 3D, 4D.

  In the configuration of FIG. 1, the time limit of the abnormality occurrence confirmation timers 3T, 4T is initially set to an appropriate value by the information processing devices (CPU) 1RC, 2RC. In this state, the test wave generators 3C and 4C periodically generate test wave signals. As a result, the test wave signal is transmitted to the switches 4R and 3R through the duplex transmission path (downstream and upstream transmission paths A and B). The pair of test wave signals input to these switches 4R and 3R are input with a transmission delay time due to the transmission characteristics of the transmission lines A and B.

  The time difference between the pair of test wave signals at this time corresponds to whether the current transmission characteristics of the transmission lines A and B are good or bad. Therefore, the switching determination devices 3J and 4J automatically correct the time limit of the abnormality occurrence timers 3T and 4T when the level drop occurs in the currently used transmission line according to the time difference between the pair of test wave signals. .

  For example, if the time difference between the paired test wave signals is 100 ms, the timer time period is automatically corrected to 100 ms. By setting such a time limit, the level of the carrier signal subsequently decreases, and when the continuation of the level recovery is recovered within 100 ms or less, the decrease in the level of the carrier signal is due to the delay time of the transmission line. It can be determined that no road switching is required. In this case, the alarm is not issued by the timer, and unnecessary switching of the transmission path can be prevented.

  Also, the time difference between the pair of test wave signals can be associated with the current transmission characteristics of the duplex transmission paths A and B as the transmission delay time, and this is displayed on the numeric indicators 3D and 4D to indicate the current state of the transmission characteristics. It can be used to promote awareness and improvement.

The block diagram of the remote monitoring control system which shows embodiment of this invention. The block diagram of the conventional remote monitoring control system which has a duplex transmission line. Transmission route switching time chart of duplex transmission path.

Explanation of symbols

1 Control station (master station)
2 Controlled station (slave station)
3, 4 switching circuit 1RC, 1SC, 2RC, 2SC Information processing device 1M, 2M modulator 1D, 2D demodulator 3R, 4R switcher 3S, 4S branching unit 3T, 4T monitoring timer 3C, 4C test wave generator 3H, 4H Synthesizer (hybrid transformer)
3J, 4J switching judgment unit 3D, 4D numeric display

Claims (2)

The master station and slave stations are connected with a duplex transmission path, the transmission side branches the transmission signal carrier signal with a branching device and transmits it with the duplex transmission path, and the reception side is switched to one of the duplex transmission paths with a switch. In the remote monitoring control system comprising a transmission line switching means for switching to the reception output from the other transmission line when the level drop of the reception signal continues for a time set by the timer time limit of the monitoring timer.
The transmission side is provided with a test wave signal transmitting means for periodically injecting a test wave signal into the branching device and transmitting it by the duplex transmission line,
A remote monitoring control system characterized in that a receiving side includes a switching determination means for detecting a time difference between a pair of test wave signals received on the duplex transmission path and automatically correcting the time difference as a timer time limit of the monitoring timer. . The remote monitoring control system according to claim 1, wherein the switching determination unit includes a unit that displays the time difference on a display.

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