JPH0530337B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a digital communication device in which each slave station (user) uses its own commercial power source.
The present invention relates to a power outage detection device for accurately detecting a power outage at a slave station at a master station.

[Prior Art] In network equipment for digital communication equipment in which each slave station is powered by its own commercial power supply, in determining the cause of communication abnormality on the slave station side, it is necessary to
It is important for the master station to accurately detect power outages on the slave station side. In other words, if a power outage on the slave station side can be accurately detected, when a communication error occurs on the slave station side, it will be possible to determine whether it is due to a power outage or an abnormality in the equipment, and this will enable quick and accurate detection. This will enable recovery activities to be carried out.

As a conventional power outage detection device for this purpose, there is, for example, one having a configuration as shown in Japanese Patent Application Laid-open No. 176341/1983.

This defines a predetermined bit indicating a power outage in the frame of the digital line from the slave station to the master station,
In the event of a power outage, by setting this bit, the master station receives the information and attempts to detect the power outage. The bit indicating the power outage is transmitted together with the normal signal from the time the power outage occurs until the secondary power supply is turned off.

[Problems to be solved] The conventional power failure detection device described above only sends a small amount of information in which a bit indicating a power failure is inserted between the normal signals, and the short period from the occurrence of a power failure until the secondary power supply is turned off is Since a power outage must be determined based on the small amount of information sent to the
There was a problem in that there was a risk of incorrect judgments being made and reliability was poor.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a power outage detection device for a digital communication device that allows a master station to accurately determine a power outage in a slave station.

[Means for Solving Problems] In order to achieve the above object, the present invention provides a digital communication device in which each slave station is driven using commercial power, in which each slave station transmits a predetermined power failure display fixed pattern signal. A power outage display fixed pattern generation means, a means for detecting a power outage and switching a transmission route from a normal digital transmission circuit to the power outage display fixed pattern generation means at the time of a power outage, and
The master station detects the power outage of the slave station based on the means for detecting the power failure display fixed pattern signal, the frame synchronization means, the detection information from the power failure display fixed pattern signal detection means, and the frame asynchronous information from the frame synchronization means. The configuration includes means for making a determination.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

The drawing is a block diagram showing a power failure detection device in a digital communication device according to this embodiment.

In the drawings, 1 indicates communication equipment on the slave station side, and 2 indicates communication equipment on the master station side.

The communication equipment 1 on the slave station side is configured as follows. That is, 3 is a power supply unit connected to a commercial power supply, 4 is a digital transmission circuit that multiplexes a main signal, a frame synchronization signal, etc., and 5 is a transmitter. Normal communication occurs from the digital transmission circuit 4 via the transmitter 5.

Further, numeral 6 in the figure is a power failure display fixed pattern generator, which continuously sends out a unique word (power failure display fixed pattern signal) that is clearly distinguishable from the simple fixed pattern that appears at the time of equipment failure. The output signal of the power failure display fixed pattern generator 6 and the output signal of the digital transmission circuit 4 are selected by a switch 7, and only one of them is transmitted to the transmitter 5.
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The switch 7 is controlled by a power outage detection circuit 8. The power failure detection circuit 8 is a circuit that detects a power failure in the commercial power supply, and when the switch 7 receives a power failure detection signal from this circuit 8, it connects the power failure display fixed pattern generator 6 to the transmitter 5.

On the other hand, the communication equipment 2 on the master station side is configured as follows. That is, 9 is a receiver, 10 is a frame synchronization circuit, 11 is a power failure display fixed pattern detector, and 12 is a judgment circuit, which separates the digital signals demodulated by the receiver 9 into a frame synchronization circuit 10 for communication signal transmission. At the same time, it is also sent to the power outage display fixed pattern detector 11 to constantly determine power outages.

The power outage display fixed pattern detector 11 has a built-in counting circuit that detects how many times the power outage display fixed pattern signal has been counted within a certain period of time, and the determination circuit 12 uses the counting result and the frame synchronization circuit 10. A power outage is determined based on the frame asynchronous information, and a power outage alarm is issued and necessary signal fixing is performed.

Next, the operation will be explained.

When a power failure occurs on the slave station side, the power failure detection circuit 8 detects it, drives the switch 7, and sends the signal from the power failure display fixed pattern generator 6 to the master station side. This continues until the secondary power of the power supply section 3 decreases and the device stops functioning. On the master station side, a power failure display fixed pattern detector 11 detects the signal and sends the detection information to the determination circuit 12. At this time, since the digital transmission circuit 4 on the child station side is disconnected from the transmission path, frame synchronization cannot be achieved, and the frame asynchronous information is sent from the frame synchronization circuit 10 to the determination circuit 10. When these two pieces of information are input, the determination circuit 10 issues a power outage alarm and performs necessary signal fixing.

By adding the above-mentioned two pieces of information to the determination elements, it is possible to accurately determine a power outage even if a code error occurs in the transmission path or a confusing pattern appears in the main signal.

[Effects of the Invention] As explained above, in the present invention, when a power outage occurs in a slave station, the slave station sends out a fixed pattern indicating a power outage instead of a normal signal with a frame signal inserted, and the master station transmits a fixed pattern indicating the power outage. The number of times the power outage display fixed pattern is determined to be sufficient for a certain period of time is counted, and
Power outages are determined based on the two conditions that frame synchronization cannot be achieved, so even if a large number of code errors occur due to a transmission line failure, for example, a power outage at a slave station can be accurately determined. This has a significant effect on improving reliability.

[Brief explanation of drawings]

The drawing is a block diagram showing a power failure detection device in a digital communication device according to an embodiment of the present invention. 1: Communication equipment on the slave station side, 2: Communication equipment on the master station side, 3: Power supply unit, 4: Digital transmission circuit, 5: Transmitter, 6: Power outage display fixed pattern generator, 7: Switching device, 8: Power failure detection circuit, 9: Receiver, 10: Frame synchronization circuit, 11: Power failure display circuit pattern detector, 12: Judgment circuit.

Claims (1)

[Claims] 1 In a digital communication device in which each slave station is driven using a commercial power source, each slave station has a power failure display fixed pattern generating means for transmitting a predetermined power failure display fixed pattern signal, and a power failure display fixed pattern generating means that detects a power outage and means for switching a transmission path from the digital transmission circuit to the power outage display fixed pattern generating means, and the master station includes means for detecting the power outage display fixed pattern signal, frame synchronization means, and the power outage display fixed pattern generating means. A power outage detection device for a digital communication device, comprising means for determining a power outage in a slave station based on detection information from the pattern signal detection means and frame asynchronous information from the frame synchronization means.