JPS6041494B2 - Motion detection method for optical fiber terminal equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a terminal device operation detection method in which a main device detects the connected state and disconnected state of switches of a plurality of terminal devices.

For example, in a steel rolling plant, many terminal devices for monitoring and control are lined up along the process line, and the operation or non-operation of these terminal devices must be detected by a main device located at a remote location. Conventionally, this type of detection was performed by connecting the main device and the terminal devices with electrical cables, and receiving the electrical signals transmitted from each terminal at the main device according to the connection status of the terminal's switch. Ta.
However, large amounts of electrical noise are generated in areas adjacent to process lines in rolling plants and the like. Therefore, the conventional detection method using electric signals has the drawback that a large-scale electric shielding network is required to prevent electric noise from being carried on the electric cable and generating unintended signals. In order to eliminate this drawback and realize a simpler configuration, this invention uses optical fibers for the signal transmission path, and sends light with a continuous emission spectrum from the main device to each terminal device. The system uses a method in which light with a wavelength assigned to the switch is sent back to the main device depending on whether the switch is connected or disconnected.The drawings will be described in detail below.

The figure shows an example of an embodiment of the present invention in which there are three terminal devices.

1 is the main device, 2, 3, and 4 are each terminal device, and an optical fiber 5 is used as a transmission path between the devices.

31 is the wavelength ^. Interference filter plate that transmits only the light of 3
2 is a Senwata filter plate that transmits only light of wavelength ^2, 33
is an interference filter plate that transmits only light of wavelength ^3,
Each pair is combined with a reflector plate 20, and this pair moves in the direction of the arrow in the figure, and when the blind switch is connected, an interference filter plate is placed in the optical path and when the switch is blocking it. A reflector is placed in the optical path.

This movement is performed using, for example, an electromagnet. The main device 1 includes a light source 9 that has a continuous emission spectrum including components of wavelengths ^, , 2, and 3, and a light source 9 that has a function of independently separating light incident from one optical path according to wavelength. A wave device is installed. For example, a tungsten lamp, a halogen lamp, etc. can be used as the light source 9 having a continuous emission spectrum. Further, as the optical wavelength demultiplexing device 10, a demultiplexing device using a prism, a demultiplexing device using a crating, or a demultiplexing device using an interference filter can be used. The continuous spectrum light emitted from the light source 9 is focused by the lens 7, enters the optical fiber, and propagates through the optical fiber 5. The continuous spectrum light propagated through the optical fiber 5 is divided by a distributor 6 and guided to each terminal device 2, 3, 4. Here, since the operations in the three terminal devices 2, 3, and 4 are the same, the operation in the terminal device 2 will be explained. The continuous spectrum light guided to the terminal device 2 is converted into parallel light by the lens 8. If there are no obstacles in the optical path, the parallel light will enter the optical fiber 5 on the output side as it is through the lens 7, pass through the distributor 6, and be guided to the optical wavelength demultiplexer 1 of the main device 1. When the switch of the terminal device is in the disconnected state, the light from the terminal device is blocked because the reflection plate 20 is inserted into the optical path. On the other hand, when the switch is in the connected state, the interference filter plate 31 that transmits only the light of the wavelength input is inserted into the optical path, so that only the light of the wavelength input of the light is included in the continuous spectrum. The light passes through and is guided to an optical wavelength demultiplexer. The terminal devices 2 and 3 operate in a similar manner, but the interference filter plate 3
Since the transmission wavelength ranges of inputs 2 and 33 are different for inputs 2 and 3, the wavelengths guided by the optical wavelength demultiplexer 101 when the switch is connected are different. Optical wavelength demultiplexer 1 of main device 1 This wavelength input is guided by optical fiber. , input 2, and input 3 are taken out independently. Therefore, for example, a light-receiving element array 40 for converting light into an electrical signal is installed here, and settings are made so that light of the input wavelength is received by the element 41, light of the wavelength ^2 is received by the element 42, and light of the wavelength ^3 is received by the element 43. For example, the connected or disconnected states of the switches of the terminal devices 2, 3, and 4 can be easily detected by detecting the signals of the light receiving elements. As described above, the terminal device operation detection method according to the present invention has the advantage that it is not affected by electrical noise because the signal is transmitted through the optical fiber. Furthermore, since each terminal device does not include an electric circuit or any active elements such as light emitting and light receiving elements, it has the advantage of a simple configuration and high reliability. The above has described a method for checking whether a terminal device is operating or not, but for example, if there are several terminal devices with rotating shafts and you want to know the rotation speed of each of them from the main device, this method is as follows. If interference filter plates and reflection plates are arranged alternately on the circumference of a disk having a rotation axis connected to the rotation axis at each terminal and installed in the optical path, a pulse train of light can be detected at the main rhombus. Since the present invention can be easily realized, the present invention can also be used as a rotation speed detection method for a terminal having a rotating shaft. As described above, in the operation detection method of the optical fiber terminal device according to the present invention, electrical noise can be prevented by using optical fibers in the transmission path, and it is possible to prevent malicious information from flowing into the transmission path. It has the effect of being able to.

Furthermore, since the terminal equipment does not include any active elements, it has the advantage of high reliability.

[Brief explanation of the drawing]

The figure shows an embodiment of the system according to the invention.

Claims (1)

[Claims] 1. In a method in which the main device detects the connected and disconnected states of switches of multiple terminal devices, an optical fiber used as a signal transmission path between the main device and the terminal device and a continuous light emitting device installed in this main device are used. A light source with a spectrum, an optical wavelength component device that has the function of independently extracting light of a plurality of different wavelength components, and a filter that reflects or transmits only light of a specific wavelength in each terminal device. The main device transmits light with the continuous emission spectrum to all terminals via optical fibers, and each terminal device transmits only light with a specific wavelength assigned to each terminal device in advance. An optical fiber terminal device operation detection method characterized in that the signal is sent back to the main device depending on whether the switch is connected or disconnected.