JPS581300A - Optical measuring system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measurement system, and particularly to an optical measurement system using an optical fiber.

Generally, in this type of measurement system, a large number of sensors are installed in the field (LK field), and the measurement signals from these sensors are transmitted to a central control room and processed as appropriate to determine the field status. In this case, if wiring is required to monitor and control the f! A field-installed remote multiplexer is installed, the multiplexer is connected to the prefectural pipe [111] by a number of lines smaller than the number of Senna, and the Senna is sequentially called from the control room, so that the signal from the Senna is A system for receiving information has already been proposed.

However, since these systems use electric 41F4#, they have the drawback of being vulnerable to electromagnetic and electrostatic induction noise and requiring appropriate countermeasures in explosive atmospheres. In addition, since it is an electrical signal, it generally requires one pair (two) of metal conductor wires, which has the disadvantage that the distance between installed devices becomes longer, or the cost increases as the number of wires increases. .

The present invention has been made in view of the above, and an object of the present invention is to provide an inexpensive and highly accurate measurement system that is not affected by noise.

The above purpose, according to this fiK, is to connect a plurality of remote multiplexers, which are commonly provided corresponding to a plurality of sensors that detect physical quantities, to a control means in cascade via one optical fiber. sends out an optical signal in which a multiplexer selection signal and a senna selection signal are superimposed on energy light, each multiplexer branches the wrinkled optical signal, and selects a predetermined processor only when a predetermined multiplexer selection signal is received from one of the multiplexers. At the same time, this is achieved by configuring the other branched optical signal to be optically modulated based on the sensor output and sent back to the control means via the next multiplexer or optical transmission line.

Hereinafter, embodiments of this invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a remote multiplexer.

In these figures, l is the central tube 31ii! Signal station 1
It is composed of an M circuit 2, a modulation circuit 3, an optical II 4, and an optical-electrical conversion circuit 5, and R1-Ra is a remote multiplexer and is composed of optical branching elements A1 to b1, party modulation elements Bl to Bm, and processor selection circuits 01 to CAL. These multiplexers R1 to Ra are optical 7 fibers Ft, Fz...
. . . is cascade-connected to the management room 1 via Fn-4-1.

In addition, 81t ~ 81p, 8ss ~ 8gq--
----8m1-5zLr is senna.

Light II4 uses high energy such as lasers,
The light 1[4 supplies energy to the remote multiplexer ~&. At the same time, a modulation circuit 3 for modulating the light source 4 according to a command from the signal processing circuit 2 is connected in order to superimpose a 5 selection command signal to select which multiplexer stripe and which number t7. There is. In each multiplexer, the optical signal sent from the control room I is branched by the optical branching element A1xAn, and the rest is sent to the sensor selection circuits C1 to Cn, which are part of the branching element A1xAn, and the rest to the optical modulation elements B1 to Bn or the optical fiber Fn- 1-1 to the next multiplexer or control room 1. In this case, only the remote multiplexer that receives the command selects a predetermined sensor and modulates the branched optical signal based on the detection output of the sensor.

In the other remote multiplexers, no optical modulation is performed, and the optical signal from the management room 1 is branched and transmitted directly to the next remote multiplexer.

The sensor selection circuit is shown in FIG. 2 (the figure shows the sensor selection circuit C1 as a representative).

It is composed of an optical branching element 10, optical-to-electrical conversion circuits 11 and 12, a selection circuit 13, and a modulation circuit 14.

The optical signal from the optical branching element A1 is further branched by the optical branching element 10K, one of which is converted into electrical energy by the optical-to-electrical conversion circuit 111'C, and is used for the electrical circuit in the multiplexer and for driving the sensor. The other signal is used as a power source, and the other signal is converted into an electric signal by an optical-electric conversion circuit and guided to the selection circuit 13. The selection circuit 13 determines whether or not it is designated, and if it is determined that it is designated, the selection circuit 13 selects a predetermined sensor, and uses the sense output from the sensor to transmit the light modulation element via the variable circuit 14. B
The IK adjusts the optical signal received from the branching element A1. In addition, 1 of the jlZ diagram! In the example, @2 optical branching cord 10
is inserted between the optical branching cable 10 and the optical-to-electrical conversion four-way 11, but it may also be inserted between the optical branching element Al and the light modulation element B1. In this case, the optical signal transmitted to the next stage is the second I! ! It is basically the same except that it is decreased compared to case 1.

As described above, according to the present invention, a plurality of remote multiplexers provided in common for a plurality of processors that detect physical quantities are connected in cascade to the central management 171 via optical fibers, and sends out an optical signal in which a multiplexer selection signal and a sensor selection signal are superimposed on energy light, and the multiplexer branches the optical signal and selects a predetermined sensor only when receiving a predetermined multiplexer selection signal from one of the multiplexer selection signals. Since the other branched optical signal is optically modulated based on the sensor output and sent to the next multiplexer or sent back to the control room via the optical transmission line, it is not affected by noise etc. This has the advantage that a highly accurate measurement system can be provided, and that the system can be constructed at a low cost since the number of optical fibers is significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a four-legged diagram showing an embodiment of the present invention, 2nd WJ
2 is a block diagram showing a part of FIG. 1 in detail; FIG. Explanation: Central control room, 2: Signal 63I enclosure, 3
, 14... Modulation circuit, 4... Light source, 5, 11.12
...Photo-electronic first figure conversion circuit, 109 people 1~AI! ...light branching element, 1
3...Selection circuit, R1-h...Remote multiplex, C1-Cm...Selection circuit, F1-Fn
+1...Optical fiber, 81t~8mr...Sensor,
Bl~Bm...Light modulation element agent Patent attorney Akio Namiki Agent Patent attorney Kiyoshi Matsuzaki @ 2 Figure

Claims (1)

[Claims] A plurality of remote multiplexers commonly provided corresponding to a plurality of sensors that detect physical quantities are connected in cascade via one optical transmission path to a control means for remotely controlling the Mukuro multiplexer, and the multiplexer is selected from the control means. Sending an optical signal in which the signal and the senna selection signal are superimposed on the energy light.
In the previous measurement system, each multiplexer includes a means for branching the optical signal, a means for extracting a multiplexer and sensor selection signal from one of the branched optical signals and selecting a predetermined sensor, and a predetermined multiplexer. and means for optically modulating the other branched optical signal in response to a detection signal from the sensor only when receiving a selection signal, and transmitting the optical signal back to the control means via a next multiplexer or an optical transmission line. The previous generation measurement system is characterized by: