JPH02219324A - Underwater wire type data collection system - Google Patents

Abstract

PURPOSE:To unnecessitate an insulating transformer of large scale by transmitting a digital signal converted from the output signal of a sensor via a photocoupler for insulation, and supplying a DC power source to the circuits formed on the middle way via an insulation type transformer. CONSTITUTION:An analog signal sent from the sensor 15, after being converted to a DC digital signal, is converted to a code for transmission at a code conversion circuit 5 via the photocoupler for insulation, and is sent to a coupling circuit 7. The circuit 7 adds the output signal of the circuit 5 on the signal from a relay circuit 6, and transmits it via a signal line 14. Meanwhile, a DC voltage between the terminals of a diode 8 on a feed line 10 is converted to an AC voltage, and is converted again to the DC voltage at a conversion circuit 13 via the insulation type transformer 12, and is fed to the circuits between the sensor 15 and the coupler 4. Thereby, it is possible to unnecessitate a large capacitor or insulating transformer even when the output signal of the sensor includes a constant frequency component in the neighborhood of DC.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an underwater wired data collection system, and in particular, measurement data obtained at multiple points under the sea is multiplexed and transmitted in cascade through a transmission line for collection. Concerning an underwater wired data collection system.

[Conventional technology]

In a conventional underwater wired data collection system of this kind, as shown in FIG. The receiving end station device 21 collects measurement data by cascade connection. When there are many measurement points or when the total length of the transmission line is long, the ground potential of the feeder line 1o increases, so normally, as shown in Fig. 3 (a) and (b).
As shown in the figure, a measurement sensor 15 and a transmission relay circuit 17
In order to provide DC insulation between the two, either a capacitor C or an insulating transformer 19 is provided.

[Problem to be solved by the invention]

In the conventional underwater wired data acquisition system described above, the output signal of the sensor 15 includes a fairly low frequency component, and if it is necessary to minimize the insertion loss to this low frequency component, the capacitor C is set to a large value. It is necessary to increase the capacity or the inductance of the transformer 19, and in either case, there is a drawback that the transmission relay device 20 must be increased in size. Furthermore, if one end of the pair of output terminals of the sensor 15 needs to be grounded, a disadvantage arises in that the capacitor C and the transformer 19 are increased in size in order to increase the withstand voltage. Another drawback is that sensors whose output signal includes a DC component cannot be used.

[Means to solve the problem]

In the underwater wired data collection system of the present invention, analog electrical signals emitted by measurement sensors are converted into digital signals to each transmitting relay device that is cascade-connected through a -line transmission path and guided to a receiving terminal device. a transmitting circuit having a signal converting means and a photocoupler for electrically insulating and transmitting the digital signal; and a transmitting circuit that provides a digital signal arriving from the transmitting relay device at the previous stage via the transmission path. A coupling circuit that time-division multiplexes the digital signal and sends it to the subsequent stage, and converts the DC power obtained from the transmission line into AC, passes through an isolated transformer, and then converts it to DC, and connects the sensor to the photocoupler. A power supply circuit is provided to supply power to the circuit.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. This figure shows an example of the configuration of a circuit used in the transmission relay device 2° in FIG. 3 is a parallel-to-serial conversion circuit for converting digital parallel signals into serial signals; 4 is a photocoupler inserted for electrical isolation; 5 is a photocoupler for electrical isolation; A code conversion circuit for converting the digital serial signal transmitted through the photocoupler into a code format for the transmission line (signal line 14); 6 a relay circuit for reproducing the PCM signal sent from the previous stage device; a coupling circuit for inserting the output signal of the code conversion circuit 5 into the time slot assigned to the own device in the PCM signal; 8 and 9 are constant voltage diodes;
10 is a power supply line for supplying direct current for the circuit power supply, 11
Reference numeral 12 indicates a DC/AC conversion circuit for converting DC power into AC, 12 an insulated transformer for AC coupling, and 13 an AC/DC conversion circuit for converting AC into DC.

In this embodiment, the analog signal of the measurement data sent by the sensor 15 is converted into a serial digital signal through the amplifier circuit 1, ADC 2, and parallel-to-serial conversion circuit 3, and then is converted into a serial digital signal by the optical signal inside the insulating photocoupler 4. The signal passes through the coupling section, passes through the code conversion circuit 5, is converted into a code format for the transmission path, and is sent to the coupling circuit 7. The coupling circuit 7 performs synchronization detection of the PCM signal regenerated and relayed by the relay circuit 6, inserts the output signal of the code conversion circuit 5 into the time slot assigned to its own device, and then transmits the signal to the subsequent stage through the signal line 14. Vertical transmission to the device.

The circuit at the stage before the photocoupler 4 in the above-mentioned transmission path (
Power is supplied to the amplifier circuit 1, ADC 2, and parallel/serial conversion circuit 3) from a power supply circuit with an insulating transformer 12 interposed therebetween. That is, the DC voltage between both terminals of a constant voltage diode 8 connected in the middle of the feeder line 10 is converted into AC by a DC/AC conversion circuit 11, and this is inputted to an AC/DC conversion circuit 13 via a transformer 12 to convert it to DC. It is converted into a driving power source for the amplifier circuit 1, ADC 2, and parallel-to-serial conversion circuit 3. Note that power for other circuits is obtained from between both terminals of the constant voltage diode 9.

In this embodiment, unlike the conventional system, an insulating transformer is not provided immediately after the sensor 15, but an insulating photocoupler 14 is provided after converting the output signal of the sump 15 into a digital signal. Therefore, there is no need to use a large isolation transformer, and it can also be used with sensors whose output signal includes a DC component.

〔Effect of the invention〕

As explained above, according to the present invention, even if the output signal of the measurement sensor includes a constant frequency component near DC, it is not necessary to use a large capacitor or isolation transformer.
Furthermore, the present invention can be applied even when the sensor signal includes a DC component.

15... Sensor, C... Capacitor, 20... Transmission relay device, 22... Receiving end station device.

Claims (1)

[Claims] Each transmitting relay device connected in cascade through a single transmission line and guided to a receiving end station device is equipped with a signal converting means that converts the analog electrical signal emitted by the measurement sensor into a digital signal, and the digital signal is electrically isolated. a transmitting circuit having a photocoupler for transmitting the signals; and a transmitting circuit that time-division multiplexes a digital signal provided from the transmitting circuit onto a digital signal arriving from the transmitting relay device at the previous stage via the transmission path, and transmits the digital signal to a subsequent stage. and a power supply circuit that converts the DC power obtained from the transmission line into AC, passes through an insulated transformer, converts it to DC, and supplies power to a circuit between the sensor and the photocoupler. An underwater wired data collection system characterized by: