JPH02243094A - Centralized monitor - Google Patents

Abstract

PURPOSE:To attain power supply and signal transmission through a common power line only by providing the common power line extended over a central monitor section and each terminal equipment, using an isolation transformer and supplying power from a commercial power supply to the common power line. CONSTITUTION:A central monitor control section 15 of a central monitor section 10 generates a call pulse of a No.1 terminal equipment 20-1 and modulates an FM modulator 14-3. Thus, an FM modulation wave is sent to a common power line 30 via a pulse transformer 13. The FM modulation wave is inputted to No.1, No.2 terminal equipment (20-1)-(20-n) via a pulse transformer 21, demodulated by an FM demodulator 22-7 to generate a call pulse. A terminal control section 23 judges whether or not the call pulse is it own pulse. In this example, since the pulse is a call pulse for No.1 terminal equipment, the control section 23 of the terminal equipment 20-1 generates an information pulse being the result of digitizing an output of a gas sensor 24, the pulse is modulated by the FM modulator 22-3 and sent to a line 30 via the transformer 21.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention is applicable to large quantities of hazardous materials such as flammable gases and flammable liquids in oil terminals, industrial complexes, power plants, steel plants, automobile factories, semiconductor factories, etc. This invention relates to a central monitoring device for centrally monitoring information such as gas leaks, fires, and abnormalities in 2 equipment at handling locations.

[Conventional technology]

As an example of an abnormality, gas leakage will be explained. In a conventional gas leak monitoring device, a central monitoring section and a plurality of gas detection sections are generally connected to each other by laying separate cables. However, in recent years, devices have been developed that transmit various types of information by providing a plurality of terminal devices on a common communication line.

[Problem to be solved by the invention]

In the conventional method of laying individual cables, the number of cables used to transmit individual alarm signals or fault status signals increases when monitoring gas leaks in a wide area such as at an oil base. There was a problem that the cost was high.

In addition, in the conventional method using a common communication line, devices that can connect up to five devices with gas detection units as terminal devices have been put into practical use, but in this example, the input terminals for the signal line and power line, and the cable inlet In addition, five input terminals for the gas detection section, a cable inlet, and an electric circuit are required, and the flameproof and explosion-proof container becomes large and heavy, making it inconvenient to handle.

Furthermore, in the latter case, since multiple terminal devices are connected to the signal line, if a short circuit occurs due to a failure of a transistor, etc. in the signal circuit of one terminal device, the entire common signal line will be short-circuited, and the overall function will be affected. The problem was that it stopped. In order to detect this short circuit, it is necessary to open the lids of a large number of explosion-proof terminal devices one after another and investigate whether there is a short circuit in each explosion-proof terminal device, which is an extremely complicated process. was there.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a centralized monitoring device that can communicate between each terminal device and a central monitoring unit at low cost.

[Means to solve the problem]

The centralized monitoring device according to the present invention includes a common power supply line extending between the central monitoring unit and each terminal device, a pulse transformer, a transmitting/receiving unit, and a central monitoring control unit on the central monitoring unit side, and a pulse transformer in each terminal device, It is equipped with a transmitting/receiving section, an information sensor, and a terminal control section.

The common power line is supplied with power from a commercial power source via an isolation transformer.

(Function) In the present invention, power is supplied to each part of the central monitoring unit and each part of each terminal device via a common power supply line, and the devices are activated. Under the supervision of the central supervisory control section, the calling pulse is FM modulated by the transmitter/receiver section and sent to the common power supply line via the pulse transformer. On the other hand, each terminal device demodulates the call pulse inputted from the common power line via the pulse transformer in the transmitter/receiver section, and if it is the call itself, the information obtained by the information sensor from the terminal control section is sent to the transmitter/receiver section. The signal is FM modulated and sent to the common power line via a pulse transformer. The central monitoring unit receives this information via a pulse transformer, and the transmitter/receiver unit demodulates it to obtain the required information. Thereafter, the terminal devices are called in sequence.

Since power is supplied from the commercial power supply to the common power line using an isolation transformer, the primary winding side and the secondary winding side are completely insulated and also electrically separated by an electric field shielding plate. Noise intrusion is prevented.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

In this figure, 10 is a central monitoring unit, 20 is a terminal device,
A common power supply line 30 is laid across both.

40 is a commercial power source.

11 is an isolation transformer, and the commercial power supply 40 is connected to the primary winding 11P.
is connected to the secondary winding 11s, and a common power supply line 30 is connected to the secondary winding 11s. 12 is an electric field shielding plate made of a conductor;
It is disposed between the primary winding 11P and the secondary winding 11S, and is grounded to provide electrostatic shielding between the two windings 11P and 11S.

Reference numeral 13 denotes a pulse transformer that serves as a signal interface, and as shown in detail in FIG. Transmission signals are sent and received from the winding 13-3. In addition, 13-4 is a choke coil, 13
-5 indicates a capacitor. 14 is a transmitting/receiving section, which includes a power supply circuit 14-12, an oscillator 14-2. FM modulator 14-3. Power amplifier 14-4. Transmission/reception switch 14-5. High frequency amplifier 14-6. It consists of an FM demodulator 14-7. 1
5 is a central monitoring control unit such as a CPU, 16 is a display such as a CRT, and the above constitutes the central monitoring unit 10.

FIG. 2 is a block diagram showing the configuration of the terminal device 20. As shown in FIG.

In this figure, 21 is a pulse transformer serving as a signal interface, and as shown in detail in FIG.
The secondary winding 21-2 is connected, and transmission signals are sent and received from the secondary winding 21-3. Note that 22-1 is a power supply circuit connected to the common power supply line 30. 22 is a transmitting/receiving section;
Power supply circuit 22-1. Oscillator 22-2. FM modulator 22-
3. Power amplifier 22-4. Transmission/reception switch 22-5. High frequency amplifier 22-6. It is composed of an FM demodulator 22-7. 23 is a terminal control unit such as a CPU, and an address setting device 23
-1, and a gas sensor 24 as a type of information sensor and an analog amplifier 25. It is connected via an A/D converter 26. The terminal device 20 is configured as described above.

In addition, in FIG. 1, 20-1 to 20- are used as the terminal equipment 20.
Although it is shown as n, it is actually No. 1 to No. 256.
A large number of them are installed.

Next, the operation will be explained with reference to the waveform diagram in FIG.

The central monitoring control section 15 of the central monitoring section 10 creates a paging pulse for the terminal device 20-1 of No. 1 as shown in FIG. 5(a), and performs FM modulation on the FM modulator/demodulator 14-3. For example, a frequency of 300 KHz is used as the carrier source. As a result, an FM modulated wave as shown in FIG. 5(b) is sent to the common power supply line 30 via the pulse transformer 13. This F
M modulation is No, 1. Both terminal devices No. 2 20-1~
2O-rl through the pulse transformer 21 and demodulated by the transmission/reception switching unit 22-7, as shown in FIG. 5(a).
Create the original calling pulse. The terminal control unit 23 determines whether this calling pulse is its own. In the current example, it is a call pulse for No. 1, so terminal device 2
The terminal control unit 23 of 0-1 creates an information pulse (gas concentration signal) by digitizing the output value of the gas sensor 24, and
FM modulation is performed by the M modem 22-3, and the pulse transformer 21
It is sent out to the common power supply line 30 via.

This FM-modulated information pulse is received by the pulse transformer 13 of the central monitoring section 1o, demodulated by the FM demodulator 14-7, its content is determined by the central monitoring and control section 15, and then stored in a memory (not shown).

Next, the No. 2 terminal device 20-2 shown in FIG. 5(C)
A calling pulse is created, and this is FM modulated as shown in FIG. 5(d) and sent to the common power supply line 3°. Thereafter, similar operations are sequentially performed on each of the terminal devices 20-1 to 20-n to transmit necessary data. Note that the data may be transmitted sequentially at regular intervals without sending the paging signal.

By configuring as shown in FIGS. 1 and 2, the common power supply line 30 serves both as a power supply line and a signal line for signal transmission. Moreover, since an FM modulated signal is used instead of simply adding pulses, accurate transmission can be performed regardless of the magnitude of the power supply voltage.

6 and 7 are the operation flowcharts mentioned above, and FIG. 6 shows the processing flow of the central monitoring unit 10,
(1) to (18) are the respective steps. Also, the seventh
The figure shows the processing flow of the terminal device 20, and (21) to (2)
6) is each step. As shown in this processing flow diagram, the central monitoring unit 1o sequentially transmits the call pulses of the processing flow diagrams for No. 1, No. 2, and thereby causes the called terminal device 20 to send out an information pulse.

〔Effect of the invention〕

As explained in detail above, this invention provides a common power supply line that extends between the central monitoring section and each terminal device, provides a pulse transformer, a transmitter/receiver section, and a central monitoring control section on the central monitoring section side, and provides a pulse transformer for each terminal device. , a transmitting/receiving section, an information sensor, and a terminal control section are provided, so that power supply and signal transmission can be performed only through a common power line, simplifying the configuration. Furthermore, since the pulses are FM modulated and sent out, stable transmission and reception can be performed without being affected by changes in the instantaneous value of the power supply voltage. Furthermore, since transmission and reception are performed via a pulse transformer, even if a short-circuit accident occurs in one terminal device due to a component failure, the overall effect will not be affected. This method has advantages such as not requiring any trouble.

Furthermore, devices that use an isolation transformer to supply power from a commercial power source are electrically insulated and have the advantage of being safe and preventing noise from entering.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing details of the configuration of a terminal device in the embodiment of FIG. 1, and FIG. 4 is a circuit diagram showing details of the pulse transformer in FIG. 2; FIG. 5 is a waveform diagram of main parts for explaining the operation of the embodiment shown in FIG. 1; 6 and 7 are flowcharts for explaining the operation. In the figure, 10 is a central monitoring unit, 11 is an isolation transformer, 12 is an electric field shielding plate, 13 is a pulse transformer, 14 is a transmitting/receiving unit,
15 is a central monitoring control unit, 16 is a display unit, 20 is a terminal device, 21 is a pulse transformer, 22 is a transmitting/receiving unit, 23 is a terminal control unit, 24 is a gas sensor, 30 is a common power line,
40 is a commercial power source. Figure 4 Figure (d) ] Purchasing wealth [ Figure Figure 4

Claims (2)

[Claims] (1) In a centralized monitoring device consisting of a plurality of terminal devices and a central monitoring section that centrally monitors these terminal devices, a common power supply line is laid between the central monitoring section and each terminal device, and the above-mentioned The central monitoring unit is connected to the common power line and supplies power to each unit, and also includes a pulse transformer that serves as a signal interface, a transmitting/receiving unit that performs FM modulation and demodulation of digital signals, and sequentially calls the terminal equipment and transmits necessary information. a central supervisory control unit that performs control to promote the above, and a transmitter/receiver unit that is connected to the common power supply line to each of the terminal devices and supplies power to each unit, and performs FM modulation and demodulation of the digital signal with a pulse transformer that serves as a signal interface. and a terminal control section that includes an information sensor and transmits required information obtained by the information sensor in response to a call from the central monitoring section. (2) The common power supply line has a primary winding connected to a secondary winding of an isolation transformer connected to a commercial power source, and an electric field shielding grounded between the primary winding and secondary winding of the isolation transformer. The centralized monitoring device according to claim 1, further comprising a board.