JPH095117A - Electronic display-type measuring apparatus - Google Patents

Abstract

PURPOSE: To obtain an electronic display-type measuring apparatus in which an amplifier and an A/D converter are not required, which can be assembled and adjusted easily and which can be constituted at low costs. CONSTITUTION: The mechanical displacement quantity, of a detection element 1, which corresponds to a physical quantity to be detected is converted into a digital signal via respective optical systems 3, 9 and a linear image sensor 5. Its output digital signal is data-processed by a microcomputer 10. The physical quantity to be detected is electronically displayed on displays 6, 7.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an electronic display type measuring device,
More specifically, the present invention relates to an electronic display type measuring device that electronically displays a physical quantity to be detected, for example, a mechanical displacement amount according to pressure using photoelectric conversion means.

[0002]

2. Description of the Related Art A detection end portion used in a conventional electronic display type measuring device for performing digital display or bar graph display is
A physical quantity to be detected, for example, a method of bonding a metal strain gauge to a metal diaphragm or a method of integrally forming a diffusion type semiconductor strain gauge on a silicon diaphragm, in order to convert pressure into an electric signal, A strain gauge type pressure transducer based on the principle of utilizing a change in electric resistance due to mechanical strain of a diaphragm or the like which receives pressure is general.

[0003]

However, since the outputs of these detectors are analog signals, in order to display them electronically, after amplifying the detection outputs through an amplifier,
It is necessary to perform A / D conversion by an A / D (analog / digital) converter.

In addition, at the time of manufacturing various detection end devices, for example, pressure transducers, output (offset voltage) at zero point
The disadvantage is that the cost of the entire electronic display system increases, including the time and effort required for adjustment, such as the need to adjust the variation and the temperature characteristics due to the ambient temperature, and the cost is generally high.

The diffusion type semiconductor strain gauge type converter is I
Although it is relatively inexpensive because it is manufactured by the same method as the C manufacturing method, the medium to be measured is in direct contact with the diffusion resistance portion, and thus the medium to be measured is limited to non-corrosive air or gas,
The measuring range is also typically 10 k for pressure measurements, for example.
It has the disadvantage of being limited to gf / cm ² (about 1.0 MPa) or less.

Another factor that promotes the complexity of the assembling / adjusting work of this type of conventional measuring and displaying apparatus is that there are too many types of pressure units and pressure ranges to be used in the field of pressure gauges, for example. It can be mentioned. For example, in addition to the above-mentioned kgf / cm ² and MPa as pressure units, kPa, cmH
There are g, mmHg, mmH ₂ O, mH ₂ O, bar, atm, psi and the like. Regarding the measurement range, the measurement ranges individually selected within the range from the vacuum region to the ultra-high pressure region are various. Therefore, the combination of these pressure units and pressure ranges is enormous, which makes the work of assembling and adjusting the pressure gauge expensive.

The present invention has been made in consideration of the above circumstances and does not require an amplifier or an A / D converter, and can be assembled and assembled.
An object of the present invention is to provide an electronic display type measuring device which can be easily adjusted and can be constructed at low cost.

[0008]

In order to achieve the above object, an electronic display type measuring apparatus of the present invention provides a detection element which produces a mechanical displacement amount according to a physical quantity to be detected and a mechanical displacement amount of this detection element. An optical system that converts the corresponding optical position signal, a linear image sensor that converts the optical signal obtained through this optical system into an electrical digital signal, and a data processing of the output digital signal of this linear image sensor It is provided with a microcomputer that outputs a signal corresponding to the physical quantity to be detected, and display means that electronically displays the physical quantity to be detected based on the output signal of the microcomputer.

[0009]

The mechanical displacement of the detection element according to the physical quantity to be detected is converted into a digital electric signal via the optical system and the linear image sensor, and the digital signal is processed by a microcomputer to electronically detect the physical quantity to be detected. Display it. By doing so, an amplifier or an A / D converter is not required, and a digital signal can be easily obtained and electronic display can be performed.

[0010]

The present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a system diagram of an embodiment in which the present invention is applied to an electronic display pressure gauge. Here, the physical quantity to be detected is pressure, and the Bourdon tube 1 is used as a detection element. When the pressure to be detected is applied to the Bourdon tube 1, the tip of the tube is displaced according to the pressure. A thin and lightweight pipe tip plate 3 is attached to the pipe tip, so that the pipe tip plate 3 is displaced in the direction of the arrow in accordance with the pressure. The tube tip plate 3 is formed with a thin slit 4 running in a direction perpendicular to the displacement direction. A light source 9 is provided on one side of the tube tip plate 3.
Is fixedly arranged, and on the other side, a linear image sensor 5 composed of a CCD array arranged along the displacement direction of the tube front plate 3 is fixedly arranged. Light from the light source 9 is emitted from the tube tip plate 3
The light passing through the slit 4 activates the CCD cell existing at the position corresponding to the displacement amount of the tube tip plate 3, and the displacement amount of the tube tip plate 3, that is, the bourdon, is activated by the output of the activated CCD cell. The pressure to be detected applied to the tube 1 can be known. The output electric signal from the linear image sensor 5 is supplied to the microcomputer 10, especially one chip.
Introduced into a microcomputer. The microcomputer 10 processes the input data from the linear image sensor 5 and outputs a digital pressure signal. With this digital pressure signal, the detected pressure value is digitally displayed on the digital display 6 including, for example, a 4-digit 7-segment LED, and is also displayed on the pseudo analog display 7 including, for example, 51 LEDs in a bar graph.

2A and 2B show an example of the structure of the electronic display pressure gauge of FIG. 1. FIG. 2A is a front view with a part cut away, and FIG. 2B is a side view showing its internal structure. It is a figure. The ring-shaped Bourdon tube 1 is arranged inside a casing 30 having a transparent cover 31 on the front surface. Bourdon tube 1
A pressure to be detected is introduced into the pipe, and the pipe tip 2 is displaced according to the pressure. A thin and lightweight tube tip plate 3 is attached to the tube tip 2 of the Bourdon tube 1. The weight of the tube tip plate 3 is, for example, about 0.2 g. Therefore, the weight burden on the tube tip 2 can be almost ignored, and the tube tip displacement amount of the Bourdon tube 1 is hardly adversely affected. A light source 9 is arranged inside the ring-shaped Bourdon tube 1. Inside the casing 30, a first printed circuit board 11 is further arranged on the rear surface side of the casing, and a second printed circuit board 12 is arranged on the front surface side of the Bourdon tube 1. A one-chip microcomputer 10 is provided on a printed circuit board 11, and a linear image sensor 5 is provided so as to be located immediately after the rear surface of the tube front plate 3. A digital display 6 and a pseudo analog display 7 are arranged on the printed circuit board 12. The pseudo analog display 7 cooperates with the scale plate 8 to display the detected pressure. A connector 13 for connecting an RS-232C (US EIA standard for input / output interface) cable is also provided on the printed circuit board 12 for performing scaling (instruction adjustment work) described later.

With the above structure, when the pressure to be detected is applied to the Bourdon tube 1, the tube tip 2 of the Bourdon tube 1, that is, the tube front plate 3 is displaced according to the pressure, and the linear image sensor 5 is displaced according to the displacement amount. The position of the slit 4 of the tube tip plate 3 with respect to is changed. In the linear image sensor 5, different CCD cells are activated by the light from the light source 9 according to the change in the slit position, and an electric signal is output from the activated CCD cell. The output electric signal of the linear image sensor 5 is data-processed by the microcomputer 10 and converted into a pressure value as described above. The detected pressure obtained as a result is digitally displayed on the digital display 6 and also displayed on the pseudo analog display 7 as a bar graph.

At the time of scaling, one end of the RS-23 connected to the setting box 14 as shown in FIG.
This is done by connecting the other end of the 2C cable 15 to the connector 13. The setting box 14 has a liquid crystal display (LC
D) 16, MODE key 17, NE
An XT (next) key 18, an ENTER key 19 and the like are arranged, and scaling (instruction adjustment work) is performed interactively as described below.

First, the MODE key 17 is pressed to select the "setting mode", and then the measurement unit, the measurement range, and the Bourdon tube characteristic are input to the microcomputer 10 in this order.
When the setting mode is selected, the unit of measurement is displayed as “unit”, and each time the NEXT key 18 is pressed, kgf / cm ² , -cmHg + k
When gf / cm ² , MPa, kPa, -MPa + MPa, -kPa + kPa, ... are repeatedly displayed and the unit of measurement to be set is displayed, press the ENTER key 19 to confirm. After confirming the measurement unit, 0 to 0 each time the NEXT key 18 is pressed in the "range" display field for setting the measurement range.
Since it is repeatedly displayed as 1.00, 0 to 2.00, ..., 0 to 500, when the measurement range to be set is displayed, press the ENTER key 19 to confirm. If the characteristic curves of the Bourdon tube 1 in the already set measurement unit and measurement range are different, number them in advance (for example, "01" for a Bourdon tube for a diameter of 60 mm and "02" for a Bourdon tube for a diameter of 100 mm). ) Select and set the one with the applicable characteristics from the managed ones. In that case, use the MODE key 17 to display "Bourdon tube characteristics:" and press the NEXT key 18 to select 01, 0
Since 2 and so on are repeatedly displayed, a desired Bourdon tube characteristic can be set by pressing the ENTER key 19 when the desired Bourdon tube characteristic is displayed. In this way, the work is simplified by selecting a desired Bourdon tube characteristic from the already input Bourdon tube characteristics.

For the scaling, first, by selecting the "adjustment mode" with the MODE key 17, first, referring to FIG.
Since the minimum pressure scaling screen is displayed as in the display example 20 of (a), the minimum pressure in the measurement range is added to the Bourdon tube 1 and the ENETR key 19 is pressed. This completes the scaling of the lowest pressure. When the scaling of the minimum pressure is completed, the maximum pressure scaling screen of the measurement range is displayed as shown in the display example 21 of FIG. 4B. Therefore, apply the maximum pressure to the Bourdon tube 1 and press the ENETR key 1
Pressing 9 completes maximum pressure scaling.

As described above, even if there is some variation in the displacement amount of the tube tip plate 3, the microcomputer 10 automatically adjusts the measurement unit, the measurement range, and the characteristics of the Bourdon tube within the variation range. Since the data is processed, scaling can be easily performed when the pressure is electronically displayed.

After the scaling is completed, all the setting items are stored in the microcomputer 10. After that, the connector 13 (Fig. 2 (b)) and the setting box 14
The RS-232C cable that is connected to (FIG. 3 (b)) can be removed and used as the electronic display type measurement device 22 shown in FIG.

Since the printed circuit board 12 of the electronic display type measuring device is generally constructed so that a contact function can be added, by adding such a contact function, an electronic device with a contact as shown in FIG. The display-type measuring device 23 can be used. In the electronic display type measuring apparatus 23 of FIG. 6, since the lower limit and the upper limit setting are selected by the mode switch 24 and the setting switch 25 is pressed, the display values of the digital display 6 and the pseudo analog display 7 can be changed. When the display value to be set is reached, the setting value can be easily fixed by releasing the setting switch 25 to stop the display value and pressing the mode switch 24. When the lower limit and upper limit set values are reached, the lower limit set value operation indicator lamp 26 and the upper limit set value indicator lamp 27 light up, respectively, and the contact operation state can be confirmed. In that case, by making the contact output a non-contact type, stable and long-life switching can be performed.

FIG. 7 is a block diagram showing the system diagram of FIG. 1 in more detail. The same or corresponding parts as those of FIG. 1 are designated by the same reference numerals. The microcomputer 10 shown in FIGS. 1 and 2 is mainly composed of a microprocessor 100, and has a nonvolatile memory 1 for storing pressure conversion parameters.
01 and a setting switch 102 for performing various settings. The nonvolatile memory 101 is composed of, for example, an E ² PROM. The linear image sensor 5 is driven by a linear image sensor driving circuit 103 controlled by the microprocessor 100.
The drive circuit 103 comprises a logic circuit, which cooperates with the light source 9 and the tube tip plate 3 to generate a sensor output. The output of the CCD cell constituting the linear image sensor 5 is basically an analog signal, which is binarized by the signal processing circuit 50 and then the microprocessor 100.
To be introduced. The microprocessor 100 performs data processing on the input signal from the signal processing circuit 50 while appropriately referring to the stored contents of the memory 101 to obtain a pressure value. The pressure value thus obtained is displayed as a bar graph on the bar graph display 7 via the bar graph LED drive circuit 70, and as a numerical value on the digital display 7 via the 7 segment LED drive circuit 60. The binary contact output circuit 80 is driven.

FIG. 8 shows the flow of processing executed by the microcomputer 10 centering on the microprocessor 100. Upon the start of measurement, necessary initialization processing is first performed (step S1), and the pressure conversion parameter is read from the nonvolatile memory 101 by the microprocessor 1
00 (step S2). Next, it is checked whether or not there is a linear image sensor scan start timer interrupt (step S3). If there is no interruption, after input processing from the setting switch is performed (step S4), LED display, that is, display processing is performed (step S5), contact output processing is performed (step S6), and the process returns to the check step S3. If there is an interrupt in step S3, the scanning counter is started (step S7),
It is checked whether or not there is a Bourdon tube tip position detection (pressure detection) interruption (step S8). If there is no interrupt here, it waits as it is, and if an interrupt occurs, the scanning counter is stopped (step S9), position data is calculated (step S10), pressure data conversion processing is performed (step S11), and step S3 is performed. Return.

Although the above description is of the embodiment of the Bourdon tube type electronic display pressure gauge, the pressure detecting element may be another detecting element which produces a mechanical displacement in response to pressure, for example, a well-known diaphragm. Type or bellows type may be used.

Furthermore, the physical quantity to be detected in the present invention is not limited to the pressure, and may be another physical quantity or detection element as long as the detection output can be obtained as the mechanical displacement. For example, the present invention can be applied to a Bourdon tube type thermometer, a bimetal type thermometer, a hair type hygrometer, a pressure plate type flow meter, a float type liquid level gauge, a weight scale and the like.

FIG. 9 shows an embodiment in which the present invention is applied to a pressure plate type velocity meter. The pressure receiving portion 35 of the pressure plate 34 is arranged in the fluid so as to take a position substantially perpendicular to the fluid flow indicated by the arrow P. The pressure plate 34 is rotatable around a shaft 37, and the displacement of the pressure receiving portion 35 generated according to the flow velocity is transmitted to the slit plate 38 via the displacement transmitting portion 36 on the opposite side. A thin slit 39 is formed in the slit plate 38 in a direction perpendicular to the displacement direction. The light source 9 is fixedly arranged on one side of the slit plate 38, and the linear image sensor 5 is fixedly arranged on the other side. The output side of the linear image sensor 5 is connected to the microcomputer 10 already described with reference to FIGS. 1 and 2. The displacement transmitting portion 36 is provided with a return spring 42 that acts so as to return it to the direction of the zero flow velocity position. When pressure is applied to the pressure receiving portion 35, pressure is applied against the spring force of the return spring 42. The plate 34 is displaced. Also in this embodiment, the flow velocity as the physical quantity to be detected is obtained as the mechanical displacement amount, and this mechanical displacement amount is converted into an electric digital signal via the optical system (9, 38) and the linear image sensor 5, and further, The data is processed through the microcomputer 10 and displayed on a digital display and a pseudo analog display.

FIG. 10 shows an embodiment in which the slit plate can be omitted, that is, a light source moving type. In this embodiment, a light pipe 46 having a light source and a condenser lens built therein and a light weight, for example, an optical box 45 to which an optical fiber is attached is provided, and the light pipe 46 is provided at a displacement detecting end 47 which responds to a pressure to be detected. It is connected. Displacement detection end 47
Can be the tip of the Bourdon tube 1 in a Bourdon tube pressure gauge, for example. In the case of this embodiment, the displacement detecting end 47 is displaced according to the pressure to be detected, the tip position of the optical conduit 46 is displaced to, for example, the broken line position Q, and the active cell of the linear image sensor 5 changes.

FIG. 11 shows an embodiment in which the light pipe 46 in FIG. 10 can also be omitted. The feature of this embodiment is that the light source 48 with a lens is directly attached to the displacement detecting end 47. According to this embodiment, it is possible to provide a cheaper product by omitting the light pipe 46 while achieving substantially the same function as the embodiment of FIG.

In the above-mentioned embodiment, the pressure and the flow velocity are exemplified as the physical quantity to be detected, but in addition to this, the present invention is not limited to the above as long as a mechanical displacement amount corresponding to the physical quantity to be detected is generated. It can also be applied to. For example,
The physical quantity to be detected may be a temperature detected by a temperature detecting Bourdon tube or a bimetal.

The digitized detection output signal relating to the electronic display type measuring apparatus of the present invention is used for centralized control of the process amount in the plant by using an optical cable or GP-IB (American IEEE standard for signal line for data transfer) bus. Therefore, it can be applied to remote transmission.

[0029]

According to the present invention, since the displacement amount of the detection element according to the physical quantity to be detected is directly taken out as a digital signal and displayed digitally, an amplifier and an A / D converter can be eliminated. Further, it is possible to provide an inexpensive electronic display type measuring device which is easy to assemble and adjust.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment when the present invention is applied to an electronic display pressure gauge.

2A is a front view in which a part of the electronic display pressure gauge of FIG. 1 is cut away, and FIG. 2B is a side view showing an internal configuration thereof.

FIG. 3 is a front view of a setting box used for scaling.

FIG. 4A is a diagram showing an example of a setting box display screen at the time of minimum pressure scaling, and FIG. 4B is a diagram showing an example of a setting box display screen at the time of maximum pressure scaling.

FIG. 5 is a front view showing the structure of an embodiment when the present invention is applied to an electronic display pressure gauge.

FIG. 6 is a front view showing an example of an electronic display pressure gauge with contacts.

FIG. 7 is a block diagram showing the system diagram of FIG. 1 in more detail.

FIG. 8 is a flowchart showing a flow of processing performed by a microcomputer.

FIG. 9 is a perspective view showing a main part of an embodiment in which the present invention is applied to a pressure plate type flow meter.

FIG. 10 is a principle diagram showing a different embodiment of the optical system in the apparatus of the present invention.

FIG. 11 is a principle view showing still another embodiment relating to the optical system in the apparatus of the present invention.

[Explanation of symbols]

 1 Bourdon tube 2 Tube tip 3 Tube tip plate 4 Slit 5 Linear image sensor 6 Digital display 7 Pseudo analog display 8 Scale plate 9 Light source 10 Microcomputer 11, 12 Printed circuit board 34 Pressure plate 35 Pressure receiving part 36 Displacement transmitting part 37 Shaft 38 Slit Plate 39 slit 42 return spring 45 optical box 46 optical conduit 47 displacement detection end 48 light source with lens

Claims (5)

[Claims] 1. A detection element for producing a mechanical displacement amount according to a physical quantity to be detected, an optical system for converting the mechanical displacement amount of the detection element into a position signal of light corresponding thereto, and via this optical system. A linear image sensor that converts the obtained optical signal into an electrical digital signal, a microcomputer that processes the output digital signal of this linear image sensor and outputs a signal corresponding to the physical quantity to be detected, and the output of this microcomputer An electronic display type measuring apparatus comprising: a display unit that electronically displays the detected physical quantity based on a signal. 2. A pressure detecting element which generates a mechanical displacement according to the pressure when receiving a pressure, a thin plate with a slit which responds to the amount of mechanical displacement of the pressure detecting element, and one side of the thin plate with the slit. A linear image sensor fixedly arranged on the other side of the thin plate with a slit and fixedly arranged on the other side of the thin plate with a slit, and outputting a digital signal corresponding to the mechanical displacement amount in response to light emitted from the light source and passing through the slit. And a microcomputer for processing the output digital signal of the linear image sensor to output a pressure signal corresponding to the pressure, and a display means for electronically displaying the pressure based on the output pressure signal of the microcomputer. Electronic display type measuring device. 3. A pressure detecting element which produces a mechanical displacement according to the pressure when receiving the pressure, a light source which responds to the amount of mechanical displacement of the pressure detecting element, and a light source which responds to the light emitted from the light source. A linear image sensor that outputs a digital signal corresponding to the displacement position of the light source, a microcomputer that processes the output digital signal of the linear image sensor and outputs a pressure signal corresponding to the pressure, and an output of this microcomputer An electronic display type measuring device comprising a display means for electronically displaying a pressure based on a pressure signal. 4. The electronic display type measuring apparatus according to claim 1, wherein the display means comprises at least one of a digital display and a pseudo analog display. 5. The electronic display type measurement according to claim 1, wherein the pressure detecting element is made of any one selected from a Bourdon tube, a diaphragm, a bellows and a pressure plate for measuring a flow velocity. apparatus.