JPH035640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a system for identifying a power outage of a monitoring and measuring device for a transmitting device and a receiving device that are located remotely.

[Description of prior art]

In general, in remote monitoring and measurement equipment, a transmitting device located in a remote location and a receiving device located at a monitoring station are connected through a dedicated communication line, and monitoring measurement data is constantly transmitted from the transmitting device to the receiving device. .

Transmitting stations located in remote locations are generally operated unmanned, and in the event of equipment failure, maintenance personnel stationed at the monitoring station will be dispatched to the remote location to restore the equipment. Consideration must be given to avoiding deployment as much as possible.

Conventionally, in monitoring stations, fault recovery measures are taken based on the type of fault detected by the remote monitoring and measurement equipment itself, but these are limited to two types: (1) errors in received data, and (2) loss of received signal level. Ta. Among these, the latter causes of the received signal level interruption include failure of the signal receiving circuit section of the receiving device, disconnection of the communication line, failure of the signal transmitting section of the transmitting device, and power interruption of the transmitting device. Of these, and are failures related to the communication system and are compatible with countermeasures, but are power supply problems that are unrelated to communication system failures and are a waste of time on the part of maintenance personnel in charge of communication lines. In order to avoid dispatch, it was necessary to distinguish this from failures in the communication system.

A more detailed explanation will be given below with reference to the drawings.
FIG. 1 shows the configuration of a conventional remote monitoring and measuring device.
That is, the parallel digital input converters 2a, 2b, 2c, . is supplied to the receiving device 2 via. Remote location input data 1a,
1b, 1c... are digital input converters 2a, 2
b, 2c, etc., and is converted into a serial code that can detect errors by a parallel/serial code converter 3,
The signal is FS modulated by the FS modulator 4 and sent to the communication line 9. In the receiving device 2, a bandpass Fullum 10, an FS demodulator 11, and a serial/parallel code converter 12 are connected in series in sequence via an input transformer or the like.
Parallel digital output converters 13a, 13b, 1
Connected to 3c... Also, the band pass filter 10
The connection point of the FS demodulator 11 and a reference power source grounded at one point are connected to the comparator 14 and output to the novel alarm 14a. In the receiving device, after unnecessary signals outside the band are suppressed by a bandpass filter 10, the carrier wave is removed by an FS demodulator 11 and the serial code is reproduced. The received signal level is compared with a reference level V by a level comparator 14, and when it is below the reference level, it is determined that the received signal level is off as described in (2) above.

[Purpose of the invention]

The present invention is intended to solve the above-mentioned problems, and aims to clearly distinguish between a failure in the communication system and a power outage on the transmitting device side.

[Key points of the invention]

According to the present invention, a device installed at a remote location is equipped with a transmitting device that transmits measurement data and monitoring data, and a device installed at a monitoring station receives an FS modulated signal transmitted from the transmitting device. In a remote monitoring/measurement method in which both devices are connected via a communication line, the transmitting device is equipped with a relay that monitors the power failure of its internal power supply, and a backflow prevention diode. The capacitor receives power from the internal power source, and the charge accumulated in the capacitor is used as the power source to calculate the deviation frequency of the FS modulated wave f ₁ = f ₀ − when the power inside the device is cut off.
It is equipped with an oscillator that continues to emit a modulated signal of Δf or f ₀ + Δf for a sufficiently longer time than the normal signal duration (T), and the contact of the relay is restored when the internal power supply to the device is cut off. When this happens, the contacts of the relay are configured so that the signal with the frequency f ₁ is sent to the communication line, while the receiver receives a signal with a time width less than or equal to the duration (T) of the modulated signal among the demodulated output signals. The demodulated output of the demodulator is configured to be branched by a delay circuit that removes the
When the receiving device receives the signal of this frequency f ₁ , it detects the power-off of the transmitting device by extracting a demodulated signal corresponding to the signal of this frequency f ₁ from the output of the delay circuit. .

[Explanation based on examples]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a configuration diagram of an embodiment of a remote monitoring and measuring device having power-off remote monitoring capability according to the present invention. In the transmitting device 1' of FIG. 2, parts having the same reference numerals as those in FIG. 1 have the same names and functions. To explain the new parts added to the conventional technology shown in FIG. and connected to capacitor C. The other end of capacitor C is grounded. Also, the connection point between relay 6 and diode D
An oscillator 7 is connected between the output of the FS modulator 4 and the output thereof via a contact 8 of a power supply monitoring relay 6 . Further, a delay circuit 16 is connected to the receiving device 2' as a part added to the receiving device 2 via the connection point between the FS demodulator and the serial/parallel code converter 12, and its output becomes a power-off alarm 16a. ing. As this delay circuit 16, an integral type delay circuit as shown in FIG. 4 is used which can ensure a relatively large delay time width.

The oscillator 7 in the transmitter 1' is an FS modulator 4
This is an oscillator that oscillates the FS deviation frequency f ₁ =f ₀ −Δf or f ₀ +Δf output by the transmitter, and continues to oscillate with the energy charged in the capacitor C even when the transmitting device is powered off. Diode D is provided to prevent the charge charged in capacitor C from flowing back to the transmitter power supply circuit 5 side when the power is turned off, and charge is normally accumulated in capacitor C through this diode.

When the power is turned off, the capacitor C has enough capacity to drive the oscillator 7 by itself for a period of time (T). The driving time (T) of the oscillator 7 is set to a value sufficiently larger than the maximum duration time of the normal modulated wave sent out from the FS modulator 4. The power failure monitoring relay 6 is in an energized state while the device is operating.
When the power to the transmitter is cut off, it is restored and the oscillator 7
The connection of the contact 8 is wired so as to connect the output of the terminal 8 to the communication line.

On the other hand, as shown in FIG.
It has a configuration that branches into .

In the device configured as described above, if a power failure occurs in the transmitter 1', the digital input converter, parallel/serial code converter, and FS modulator will be cut off from electricity supply and stop operating, but the capacitor The oscillator 7, which uses C as a power supply source, continues to operate for a while and sends out a signal of frequency f ₁ to the communication line via the contact 8 of the relay 6. In the receiving device 2', the signal of frequency f ₁ matches the normal FS modulated wave, so it is not blocked by the bandpass filter 10 and is demodulated by the FS demodulator 11, and then sent to the serial/parallel code converter 12 and the above-mentioned is supplied to the delay circuit 16 of. However, since the signal input to the serial/parallel code converter 12 has a long duration, it is determined to be a code error and is discarded. The signal branched and inputted to the delay circuit 16 is delayed for a time τ, as shown in FIG. 3c, and then taken out to the outside and acts as a power-off detection signal. The delay time width τ of this delay circuit 16 is determined by the rise time width of this circuit until reaching the specified threshold value. Therefore, when a pulse signal with a time width smaller than the rise time width is input to the delay circuit 16, it is subjected to an integral action and does not reach a prescribed threshold value, so that it disappears.
Therefore, even if a normal demodulated signal is input to the delay circuit 16, since the duration is short, it will not disappear in the delay circuit 16 having the delay time τ and will not erroneously become a power-off detection signal.

〔Effect of the invention〕

As explained above, the present invention is configured to transmit a single-frequency signal within the same band as a normal carrier signal when a power failure occurs in the transmitting device, and the receiving device identifies and separates the signal. By doing so, it is possible to detect a power outage of a transmitting device separately from a disconnection of a communication line or other related failures, and avoid unnecessary dispatch to a remote location.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional remote monitoring and measuring device. FIG. 2 is a configuration diagram of an apparatus according to an embodiment of the present invention. FIG. 3 is a time chart of signals of various parts of the apparatus according to the embodiment of the present invention. FIG. 4 shows an example of the configuration of a delay circuit according to an embodiment of the present invention. 1, 1'... transmitting device, 2, 2'... receiving device,
2a, 2b, 2c...digital input converter, 3
...Parallel/serial code converter, 4...FS modulator,
5... Transmitter power supply circuit, 6... Power failure monitoring relay, 7... Oscillator, 8... Contact of relay RL, 1
0...Band pass filter, 11...FS demodulator,
12...Serial/parallel code converter, 13a, 13
b, 13c...Digital output converter, 14...
Comparator, 15...Delay circuit, V...Reference voltage source, a...Modulation signal, b...FS modulation wave, c...
...Demodulated signal, d...Delay circuit output.

Claims (1)

[Claims] 1. A transmitting device for transmitting measurement data and monitoring data to a remote location, a receiving device for receiving an FS modulated signal transmitted from the transmitting device at a monitoring station and restoring the data, In a remote monitoring and measurement device in which the transmitting device and the receiving device are connected via a communication line, the transmitting device includes a relay that is energized by the power source of the transmitting device, and a relay that is energized by the power source of the transmitting device, and a relay that is energized by the power source of the transmitting device, and a relay that is energized by the power source of the transmitting device. an oscillator that uses the charge accumulated in the capacitor as a power source to generate a signal having a frequency substantially equal to the FS modulation signal and having a longer connection time than the pulse of the FS modulation signal; and the relay. a circuit that sends the output of the oscillator to the communication circuit via a circuit that closes when the FS modulation signal is in the released state; A power failure detection method for a remote monitoring and measuring device, characterized in that the method includes means for sending an alarm output when a signal having a duration longer than the pulse of the FS modulated signal arrives.