JPH0113593B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an optical transmission sensor module that is connected in the middle of an optical fiber bus line and optically transmits a sensor output responsive to a predetermined physical change.

Recently, the application of optical transmission to control systems for general mechanical plants and the like has been proposed. for example,
In mechanical plant control systems that use a large number of sensors such as limit switches, temperature switches, proximity switches, pressure switches, etc., in most conventional systems, each sensor is connected to a control device using a separate electrical signal cable. However, the wiring cost and wiring space became a major problem, and it also had the disadvantage of poor noise resistance. Therefore, the above problem can be solved by transmitting the output of this type of sensor to the control device by optical transmission, especially by multiplexed optical transmission using a bus line configuration.

The present invention was made in view of the above-mentioned background, and its object is to install one or several sensors in a case connected to the middle of an optical fiber bus line according to a predetermined optical transmission control procedure. In an optical transmission sensor module in which a transmitter/receiver unit that transmits output is integrated into a module, when a plurality of such modules are installed and used in relatively close positions, each module is combined and joined together. This allows an optical transmission bus line to be automatically formed without the need to connect each module with an optical fiber, thereby reducing wiring costs and wiring space, and making the entire optical transmission sensor more compact. The goal is to provide modules.

In order to achieve the above object, the present invention provides a pair of optical connector receptacles A and B to which optical fibers constituting the bus line are coupled, which are provided at symmetrical positions on both sides of the module case, and two of the same configuration. It has a joining structure in which two modules are joined with one receptacle A and the other receptacle B facing each other, and in this joined state, the receptacle A of one module and the receptacle B of the other module are directly connected. It is characterized by being configured to perform optical transmission.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

1 and 2 are a sectional view and a perspective view of one optical transmission sensor module 1 according to the present invention. The case of this module 1 has a substantially rectangular parallelepiped shape with a mounting bracket 2 on one side, and optical connector receptacles 3A, 3 are placed symmetrically on both sides of the case.
Optical fibers 4A, 4B constituting an optical transmission bus line are formed in the receptacles 3A, 3B.
Optical connector plugs 5A and 5B at the tips of the connectors are detachably fitted and attached.

The receptacles 3A and 3B consist of a conical recess, and a plug locking protrusion 6 is formed on the inner peripheral surface near the opening, and a photoelectric signal conversion element that converts an optical signal and an electric signal is provided at the innermost part. 7A and 7B (including a light emitting element, a light receiving element, or both) are arranged. On the other hand, plugs 5A and 5B
has a roughly conical shape, and the end faces of the cores of the optical fibers 4A, 4B face the top of the tip thereof. When inserted into the receptacles 3A, 3B, the end faces of the cores of the optical fibers 4A, 4B face the photoelectric signal conversion element 7.
Corresponding to A and 7B, optical signals are exchanged between them. In addition, the plugs 5A and 5B have locking steps 8.
An elastic locking piece 9 having a
When plugs A and 3B are inserted, the locking protrusion 6 and the locking step 8 fit together to prevent the plugs 5A and 5B from coming off. However, if the plugs 5A, 5B are pulled while pressing the elastic locking piece 9 with a fingertip, they will come off from the receptacles 3A, 3B.

The photoelectric signal conversion elements 7A and 7B are attached to a circuit board 10 inside the module 1, and serve as transmitting/receiving elements of a transmitting/receiving circuit configured on this circuit board 10. That is, the optical signals given from the optical fibers 4A and 4B constituting the bus line are converted into electrical signals and input to the above-mentioned transmitting/receiving circuit, and the electrical signals output from this transmitting/receiving circuit are converted into optical signals and transferred to the optical fibers. Send to 4A and 4B. This optical transmission function transmits the sensor output, which will be described later, to the control device according to a predetermined transmission control procedure.

In this embodiment, one module 1 has two
Optical signal type sensor attachments 11 can be attached. That is, the optical connector plug 13 of the sensor attachment 11 is detachably attached to the two optical connector receptacles 12, 12 provided on the front surface of the module 1. The receptacle 12 has a substantially conical recess, and the photoelectric signal conversion element 14 attached to the circuit board 10 is disposed at the innermost part thereof. On the other hand, the plug 13 has a substantially conical shape, and the end face of the optical fiber 15 is exposed at the top of its tip, and by screwing it into the receptacle 12, the two are connected, and the photoelectric signal conversion element 14 and the optical fiber are connected. 15
Optical signals are exchanged between the two. A directional coupler (not shown) is provided on the photoelectric signal conversion element 14 side so as to separate the optical signal to be sent to the optical fiber 15 from the optical signal from the optical fiber 15.

The illustrated sensor attachment 11 irradiates an optical signal given to an optical fiber 15 from a photoelectric signal conversion element 14 to the outside through a head 16 equipped with a lens, etc., and sends the reflected light of the optical signal back to the head 1.
This is an attachment similar to a so-called reflective photoelectric switch, in which the light is guided from 6 to an optical fiber 15 to a photoelectric conversion element 14, and the presence or absence of the reflected light is the sensor output. Note that the present invention is not limited to the sensor attachment with this structure,
Various structures and systems are available.

Here, a structure in which a plurality of modules 1 having the same configuration are combined and joined together will be described. 4 on the side of the module 1 on the receptacle 3A side.
Four joining holes 17 are formed, and four joining pins 18 are integrally formed at positions symmetrical to the joining holes 17 on the opposite side surface of the receptacle 3B. Then, as shown in FIGS. 3 and 4, when a plurality of modules 1 having the same configuration are joined together side by side by fitting the joining pins 18 into the joining holes 17 of each other, the plurality of modules 1 form an integral collective module. As shown in the figure, the joining pin 18 is formed with a small protrusion for locking, and the joining hole 17 is formed with a small recess for locking, and the elastic fitting between the two provides the joint strength between the modules 1. ing.

When the modules 1 are joined together using the joining holes 17 and the joining pins 18 as described above, as shown in FIG.
A and the receptacle 3B of the other module 1 fit perfectly, and the conical recesses of both receptacles 3A and 3B face each other to form a closed space. The optical signal emitted from the photoelectric signal conversion element 7A on the receptacle 3A side passes through the closed space and passes through the photoelectric signal conversion element 7B on the receptacle 3B side.
The light is received by the Similarly, the optical signal emitted from element 7B is received by element 7A. Therefore, the optical fiber 4 is connected between two adjacent modules 1, 1.
Since optical signals can be received and received without wiring A and 4B, by connecting optical fibers 4A and 4B to the receptacles 3A and 3B of module 1 on both sides, these aggregated modules can be connected to the optical transmission bus line. are joined in the middle.

Note that the inner surfaces of the conical recesses of the receptacles 3A and 3B are mirror-finished by aluminum vapor deposition, etc., so that the spatial propagation of optical signals during the above-mentioned module bonding can be carried out with high efficiency. Also,
Since the mirror surface has a tapered shape, when the optical signal is propagated in space, the mode of the optical signal is converted from high-order to low-order, and only light in the low-order mode is propagated and received.

As explained in detail above, according to the optical transmission sensor module according to the present invention, when multiple modules are used in relatively close locations, there is no need to connect each module with an optical fiber; All you have to do is connect the modules together to form a very compact aggregate module as a whole, and connect this aggregate module to the optical fibers that make up the bus line. is formed.
Therefore, the wiring cost and wiring space for optical fibers can be significantly reduced, and it greatly contributes to the realization of uncomplicated, compact, and highly reliable control systems that use optical transmission in mechanical plants, etc. do.

[Brief explanation of drawings]

1 and 2 are a sectional view and a perspective view of one optical transmission sensor module to which the present invention is applied,
3 and 4 are a perspective view and a sectional view of a main part of a state in which a plurality of the above modules are joined together. 1...Module, 3A, 3B...Receptacle, 4A, 4B...Optical fiber, 5A, 5B...
Plug, 7A, 7B...Photoelectric signal conversion element, 10
...Circuit board, 11...Sensor attachment,
17...Joining hole, 18...Joining pin.

Claims (1)

[Claims] 1 An optical transmission sensor module that is connected in the middle of a bus line by an optical fiber and optically transmits a sensor output that responds to a predetermined physical change, and is connected to the optical fiber that constitutes the bus line.
A pair of optical connector receptacles A and B are provided at symmetrical positions on both sides of the module case, and two modules with the same configuration can be connected to one receptacle A.
and the other receptacle B are joined in a state where they face each other, and in this joined state, direct optical transmission can be performed between the receptacle A of one module and the receptacle B of the other module. An optical transmission sensor module characterized by the following configuration.