JPS59102112A - Digital converter device for rotary angle - Google Patents

Abstract

PURPOSE:To improve explosion proof property in a dangerous region, by connecting a symbol plate and photoelectric conversion elements by optical fibers in a liquid level meter and the like. CONSTITUTION:A symbol plate 6 is attached to a central shaft 7, which is coaxially rotated with a rotary output shaft 5 of a liquid level meter 4. A pattern, wherein mirror surface parts 8 and light absorbing parts 9 are radially provided at an equal interval, is provided on the surface of the sign plate 6. Light beams are projected on the surface of the sign plate from a pair of optical fibers 10 and 11. The reflected light beams from the mirror surface parts 8 are transmitted to photoelectric conversion elements 16a and 16b from the other ends of the optical fibers. Prisms 12 and 13 are attached to the other ends of the optical fibers 10 and 11 in this case. Emitted light beams from light sources 14 and 15 are introduced. The positions of the light projecting ends of the fibers are shifted by the half width of the pattern of the mirror surface part 8 or the light absorbing part 9.

Description

[Detailed description of the invention] The present invention relates to a digital conversion device.

The liquid level measuring device detects the displacement of the float floating on the liquid surface with a liquid level gauge connected with tape, indicates it with a pointer, and also extracts the change as a rotation angle and converts it into an electrical signal.

However, if the object to be measured is highly flammable hazardous material such as oil or chemicals, using electricity near the storage tank is extremely dangerous, so explosion-proof measures must be taken into consideration. Ta.

Therefore, the present invention has been made with attention to these points, and it is possible to provide a rotation angle digital conversion device that does not use electricity in a hazardous area and eliminates the need for explosion-proof measures. I made it.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiment diagrams in which the present invention is applied to a liquid level measuring device.

In the figure, 1 is a tank that stores oil, chemicals, etc. A float 2 is floating on the surface of the liquid stored in this tank 1, and a tape 3 connected to this float 2
Fluctuations in the liquid level are transmitted to the liquid level gauge 4. The liquid level gauge 4 indicates the liquid level with a pointer, and can also be read out as a rotation angle using an output shaft 5.

Further, 6 is a disc-shaped code plate, and this code plate 6 is attached to a central shaft 7 that rotates coaxially with the output shaft 5. The surface of the code plate 6 has mirror surface portions 8, 8. ．． ．． and light absorbing portions 9, 9. ．． ．． is repeated radially at the same interval to provide multiple patterns.

That is, if there are N patterns of mirror surface portions 8 and light absorption portions 9 on the surface of the code plate 60, the width of each pattern is 180°.
It becomes 7N.

10.11 each indicates an optical fiber, and this optical fiber 1
At one end of 0 and 11 is a half mirror prism 12.
13, a portion of the light from each light source 14.15 is transmitted through the prism 12.13, and the rest is reflected at the sides of the prism 12.13 and transmitted into the optical fiber 10.11. It has become. The other end of this optical fiber 10.11 is used as an irradiation end to irradiate the surface of the code plate 60, but the position of the irradiation end is shifted by half the pattern width of the mirror surface section 8 or the light absorption section 9. They are arranged at the same time.

The light transmitted into the optical fiber 10.11 irradiates the surface of the code plate 60, and when it irradiates the mirror surface part 8, it is reflected and travels through the optical fiber 10.11 again, and passes through the prism 12.13.
Some of the light is reflected by the sides of the prisms 12 and 13 and escapes to the outside as shown in FIG. is converted to Phototransistor 16a
, 16b, the emitter and collector become conductive. However, when the irradiation end of the optical fiber 10.11 irradiates the light absorbing section 9, there is no reflection transmission of light, and the phototransistors 16a, 16b & Since there is no irradiation, the emitter and collector are in a non-conducting state.

Here, from the positional relationship of the irradiation ends of the optical fibers 10 and 11, the outputs of the phototransistors 16a and 16b are
Assuming that it rotates clockwise, the result will be as shown in Figure 4 cA) @. As is clear from these two-phase outputs, when the collector output of the phototransistor 16b moves from low level to NO/I level while the collector output of the phototransistor 16a is at a high level, it rotates clockwise and changes from NO/I level to low level. If it moves, it is a left rotation. This rotation direction judgment point appears at every pitch of the pattern, so for example, if the output shaft 5 of the liquid level gauge 4 is
00mm 71 rotations, one rotation of the code plate 6 is 100
pitch (the above-mentioned N is ioo), the relationship between the code plate 60 rotations and the rotation direction determination points is 100 points/one rotation. Therefore, if pulses, which will be described later, are generated at the determination point, the number of pulses is 100 pulses/one rotation, and one pulse corresponds to 1 rrIm. If this is integrated by an up-down counter and the count value of the counter at the zero liquid level point is set to zero, the liquid level and the integrated value of the counter will match from then on.

The specific configuration thereof will be explained with reference to FIG. 5. In the figure, 18 is an input terminal connected to the collector of the phototransistor 16b, 19 is a monostaple multipipe rake, and this monostaple multivibrator 19 As shown in FIG. 6, the output points are the pulses of point W during clockwise rotation and point X during counterclockwise rotation, so the output of monostaple multivibrator 19 and the emitter and collector output of phototransistor 16a are The signal at the input terminal 20 connected to is passed through an AND gate 21 to remove the pulse at the point X, leaving only the pulse at the point W as an up-count pulse. Furthermore, when the monostaple multivibrator 23 is operated using the emitter and collector outputs of the phototransistor 17 as signals from the inverter 22, the pulses are at the Y point when rotating clockwise and at the two points when rotating counterclockwise. However, since what is needed is a pulse at two points, only two pulses are made through the AND gate, and this is used as a down-count pulse. This up-down count pulse is the up-down counter 2
The contents of this counter are converted into numbers by a decoder 26 and displayed as a decimal number by a display 27.

7 and 8 show another embodiment of the invention.

In the case of FIG. 7, the code plate 6a has light shielding parts 28, 28. ．． ．． and transparent parts 29, 29. , , the mirror surface portions 8, 8 . ．． ．． and light absorption part 9.9. , , and the code plate 6
The configuration is such that light is sent through an optical fiber 30 having a divided irradiation end, received by light-receiving optical fibers 31a and 31b, and outputted to photoelectric conversion elements 16a and 16b, respectively.

FIG. 8 shows an example in which the code plate 6b is configured as an absolute transmission system, and it is of course possible to adopt an absolute transmission system other than the incremental transmission system.

Since the rotation angle digital conversion device according to the present invention is configured as described above, there is no need to use electricity in a hazardous area, and it is excellent in explosion-proof properties and can be used safely.

[Brief explanation of drawings]

FIG. 1 is an optical system diagram showing an example of a device according to the present invention, and FIG.
The figure is an enlarged view showing one end of the optical fiber, Fig. 3 is an enlarged front view showing the irradiation position of each optical fiber with respect to the code plate, and Fig. 4 (5) (Bl is a waveform indicating the emitter-collector output of each phototransistor. Figure 5 is an integration display circuit diagram,
FIG. 6 is a waveform diagram showing the relationship between the emitter-collector output of the phototransistor and the pulse output of the monostaple multivibrator, and FIGS. 7 and 8 are respective optical system diagrams showing other embodiments. 4 in the figure Liquid level gauge 5 Output shaft 6+6a, 6b Code plate 7 Center shaft 8 Mirror surface part
9 Light absorption part 10.11, 30 Optical fiber 16.17, 16a, 171) Phototransistor applicant Tokyo Keiso Co., Ltd. agent Patent attorney 1) Kiyomi

Claims (1)

[Claims] It has a disc-shaped code plate attached to a central shaft that rotates coaxially with the rotational output shaft, and the code plate has a mirror surface or a light-shielding part and a light-absorbing part or a transparent part arranged radially at the same interval on the surface of the code plate. A plurality of patterns are provided, and a pair of optical fibers is provided for irradiating light onto the surface of the code plate, and the irradiation ends of the pair of optical fibers shift the half-width position of the backlight, and a photoelectric conversion element corresponding to each party fiber is provided. It is equipped with a rotation angle digital conversion device.