JP2005057363A - Power failure messaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power failure messaging system for a remote supervisory control system by carrying out power failure messaging independently of the hardware so as to avoid a cost increase without the need for an excessive space. <P>SOLUTION: An apparatus of a station to be controlled carries out power failure messaging by using a primary power supply under voltage detection signal detected by a power supply of the apparatus by means of software in compliance with the HDLC procedure on the occurrence of the power failure. The apparatus can interrupt HDLC frames on the way of communication to be capable of carrying out the power failure messaging on the occurrence of the power failure. The apparatus uses a global address in the HDLC procedure as a power failure messaging signal to be able to carry out the power failure messaging by using a U frame being the shortest frame. Since the apparatus can transmit the frame in a short time, no backup power supply is required but a capacitor or the like ordinarily installed in the apparatus power supply is enough to transmit the frame. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a remote monitoring control device (hereinafter referred to as TM / TC) system in which communication is performed between a control station device and a controlled station device according to an HDLC procedure, and a power failure occurs in the controlled station device. This is related to the power failure notification method.
[0002]
[Prior art]
In TM / TC, when data transmission is interrupted, it is necessary to quickly investigate and restore the cause of the data transmission interruption. Factors that cause the data to be interrupted include a transmission line disconnection and a power outage. It is important to classify the cause by transmitting a power failure signal.
FIG. 5 is an example of the prior art. The controlled station device 51 and the control station device 52 are usually several kilometers to several tens of kilometers away and transmit data via the line 59. When the primary power input 510 of the controlled station device 51 disappears due to a power failure, the line is switched from the modem unit 55 to the power failure signal transmission circuit 517 by the primary power supply undervoltage detection signal 514. A signal indicating a power failure is transmitted from the power failure signal transmission circuit 517 through the line 59.
[0003]
A backup power source 516 is provided in the power failure signal transmission circuit 517 and the line switching circuit 518. In many cases, the apparatus power supply 53 uses a general controller power supply. When a power failure occurs at the primary power input 510, the secondary power supply 512 disappears in a short time. Therefore, the power failure signal transmission circuit 517 and the line switching circuit are used. In order to back up 518, a backup power source 516 is required.
The control station apparatus 52 branches the signal at the line branch circuit 520 and always intercepts the power failure signal. The power failure signal is received, and then the power failure signal of the controlled station device 51 is determined by disconnecting the line (due to the absence of the secondary power supply 512 of the controlled station device 51), and the power failure signal 515 is output. Japanese Patent Application Laid-Open No. 2004-133826 discloses such a power failure notification as hardware.
[0004]
As described above, the power failure notification is conventionally performed in hardware, the power failure signal transmission circuit 517 and the power failure signal reception circuit 519 are provided, and the power backup signal transmission circuit 517 can operate until a power failure signal is transmitted even during a power failure. There was a need to do.
[0005]
[Patent Document 1]
JP-A-6-266292 [0006]
[Problems to be solved by the invention]
Since the power failure notification of the controlled station device is performed in hardware in TM / TC, a transmission circuit of the controlled station device, a backup power source, a receiving circuit of the control station device, and the like are necessary, which increases the cost. In addition, these hard spaces have hindered the downsizing of TM / TC.
In view of the above, an object of the present invention is to provide a power failure notification method for a remote monitoring and control system that does not cause an increase in cost and does not require extra space by not performing a power failure notification in hardware. To do.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a remote monitoring control system in which communication is performed between a control station apparatus and a controlled station apparatus according to an HDLC procedure. If an undervoltage of the primary voltage input to the power supply apparatus of the local station is detected during communication, communication with the control station apparatus by the HDLC procedure is interrupted, and the shortest frame is used using the global address of the HDLC procedure. Is transmitted to the control station device as a power failure notification signal, and the control station device receives the power failure notification signal at least once, and then determines that the controlled station device is out of power when a line disconnection is detected.
The shortest frame used as a power failure notification signal is the U frame of the HDLC procedure.
[0008]
Furthermore, the controlled station device transmits a power failure notification signal as long as there is a secondary voltage of the power supply device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a remote monitoring control system to which a power failure notification method according to the present invention is applied. In FIG. 1, a controlled station apparatus 1 is installed at a distance of several to several tens of kilometers from the control station apparatus 2 and data transmission is performed through a line. The primary power input 10 is supplied to the controlled station device 1. The device power supply 3 of the controlled station device 1 constantly monitors the voltage of the primary power supply input 10 and outputs a primary power supply undervoltage detection signal 14 to the transmission control unit 4 when an undervoltage is detected.
The transmission control unit 4 immediately suspends the transmission frame by the primary power supply undervoltage detection signal 14 and global address (global address is address '11111111' (all are 1 and address 255) and is used for power failure notification) U-frames (frames for sending a mode request / response or error report, no transmission / reception number, line disconnection, transmission mode switching, etc. in the present invention, a frame for reporting a power failure) As long as the secondary power supply 12 is present, it is output to the modem unit 5.
[0010]
The modem unit 5 modulates the signal input from the transmission control unit 4 and transmits a U frame to the line 9 as long as the secondary power supply 12 is present. The modem unit 8 of the control station apparatus 2 demodulates the received signal (U frame) and outputs it to the transmission control unit 7. The transmission control unit 7 receives the U frame of the global address even once, and when a line break is detected after a certain time, the transmission control unit 7 determines that the controlled station apparatus 1 is out of power and outputs a power outage signal 15.
FIG. 2 shows a timing chart 1 of the present invention (a timing chart when the primary power input 10 of the controlled station apparatus 1 of FIG. 1 is in a power failure). In FIG. 2, the controlled station apparatus 1 side detects that the voltage of the primary power input 10 is lowered due to a power failure, and outputs a primary power shortage detection signal 14. In response to the primary power shortage detection signal 14, the modem unit 5 interrupts the I frame (information frame, which is a frame for transmitting information) by the HDLC procedure, and transmits the U frame.
[0011]
Since the secondary side power supply voltage generally has a backup time of about 100 μs as a power supply for the controller, a U frame can be transmitted. In FIG. 2, the U frame is transmitted twice. In the third time, since the secondary side power supply voltage starts to drop, it is not transmitted.
On the control station apparatus 2 side, the I frame and the U frame transmitted from the controlled station apparatus 1 are received. Further, the line disconnection state is detected from the line carrier level (the level of the transmission signal in the modem transmission between the control station and the controlled station). Based on the U frame and line disconnection, the transmission control unit 7 of the control station apparatus 2 determines that a power failure has occurred and outputs a power failure signal 15.
FIG. 3 shows a timing chart 2 of the present invention (when the primary power input 10 of FIG. 1 fluctuates). FIG. 3 is a timing chart when the primary power input 10 of the controlled station apparatus 1 fluctuates and the primary power shortage detection signal 14 is temporarily output, but is not actually determined as a power failure. In FIG. 3, on the controlled station apparatus 1 side, the primary power input 10 fluctuates, the primary power supply undervoltage detection signal 14 is output, the transmission frame is immediately interrupted, and the global address U frame is transmitted to the control station apparatus 2. .
[0012]
On the control station device 2 side, the U frame of the global address is received, but since a line disconnection (determined by the line carrier level) does not occur after a certain period of time, a power failure signal is not output and the controlled station device 1 Must not. In this way, by combining the U-frame reception of the global address and the line disconnection, it is possible to prevent erroneous determination of a power failure.
FIG. 4 shows a process flowchart of the transmission control unit 4 in the controlled apparatus 1 of the present invention for realizing the time charts of FIGS. 2 and 3.
When the transmission control unit 4 detects an undervoltage detection signal by interrupting the primary power supply undervoltage detection signal or monitoring the primary power supply undervoltage detection signal at regular intervals, the transmission control unit 4 checks the frame transmission state at that time (step S1). At that time, if it is determined that the frame is being transmitted (step S2), the transmission of the I frame is stopped as shown in FIGS. 2 and 3 (step S3), and a global address U frame is created (step S4). The U frame is transmitted to the control station apparatus (step S5).
[0013]
After transmitting the U frame, it is determined whether an undervoltage is being detected (step S6). If an undervoltage is being detected, steps S5 and S6 are repeated as long as there is a secondary voltage, Are repeatedly transmitted to the control station apparatus. If the undervoltage cannot be detected due to the disappearance of the undervoltage detection signal or the disappearance of the secondary side voltage, the process jumps to the initial state of the HDLC procedure (step S7).
If it is determined in step S2 that transmission is not in progress, the process proceeds to step S4 to create a U frame, and U frame transmission is executed in the same manner.
[0014]
【The invention's effect】
As described above, according to the present invention, the U-frame is transmitted by using the primary power supply undervoltage detection signal from the apparatus power supply of the controlled station apparatus so that the I frame in the HDLC procedure can be interrupted halfway. However, it is now possible to report a power outage by determining a power outage in combination with the line disconnection status.
Further, since the software of the transmission control unit 4 and the transmission control unit 7 is modified, the backup power source of the controlled station device, the power failure signal transmission circuit, the line switching circuit, the line branch circuit of the control station device, the power failure signal reception circuit This eliminates the need for a low-cost and compact configuration.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a timing chart when the primary power input 10 of the controlled station apparatus 1 of FIG.
FIG. 3 is a timing chart when the primary power input 10 of FIG. 1 fluctuates.
4 is a processing flowchart of a transmission control unit 4. FIG.
FIG. 5 is a configuration diagram of a conventional remote monitoring control system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Controlled station apparatus 2 Control station apparatus 3 Device power supply of controlled station apparatus 4 Transmission control part of controlled station apparatus 5 Modem part of controlled station apparatus 6 Device power supply of control station apparatus 7 Transmission control part 8 of control station apparatus Modem section 9 of control station apparatus Line 10 connecting controlled apparatus and control station apparatus Primary power input 11 of controlled station apparatus Primary power input 12 of control station apparatus Secondary power supply 13 of controlled station apparatus 13 Secondary power supply 14 Primary power supply undervoltage detection signal 15 Power failure signal 51 Controlled station device 52 Control station device 53 Device power supply 54 of controlled station device Transmission control unit 55 of controlled station device Modem unit 56 of controlled station device Device power source 57 of control station device Transmission control unit 58 of control station device Modem unit 59 of control station device Line 510 connecting controlled station device and control station device Primary power source input 511 of controlled station device Primary power source input of control station device 5 2 Secondary power supply 513 of controlled station apparatus Secondary power supply 514 of control station apparatus Primary power supply shortage voltage detection signal 515 Power failure signal 516 Backup power supply 517 Power failure signal transmission circuit 518 Line switching circuit 519 Power failure signal reception circuit 520 Line Branch circuit

Claims (4)

In a remote monitoring and control system configured to perform communication between the control station apparatus and the controlled station apparatus by the HDLC procedure,
When the controlled station apparatus detects an undervoltage of the primary side voltage input to the power supply apparatus of the local station during communication with the control station apparatus, the controlled station apparatus interrupts communication with the control station apparatus according to the HDLC procedure, Send the shortest frame as a power failure notification signal to the control station using the global address of
The control station apparatus receives the power outage notification signal at least once, and then determines that the controlled station apparatus is out of power when it detects a line disconnection. 2. The power failure notification method for a remote monitoring control system according to claim 1, wherein the shortest frame used as a power failure notification signal is a U frame of an HDLC procedure. 3. The power failure notification method for a remote monitoring control system according to claim 1, wherein the controlled station device transmits a power failure notification signal as long as the secondary voltage of the power supply device is present. 3. The power failure of the remote monitoring control system according to claim 1, wherein the control station device prevents an erroneous determination by determining a power failure when a line disconnection is detected for a certain time after receiving the power failure notification signal. Reporting method

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