JPH04252Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to an improvement of an inclinometer as described below, and relates to an inclinometer equipped with a temperature correction circuit. First, an overview of a conventional inclinometer will be explained with reference to FIG. FIG. 1 is a diagram showing the state of both magnetic poles N-N that appears when the inclinometer is tilted to the left.
When tilted to the right, the voltage of the position detector 5 is reversed, and both magnetic poles of the coil 3 become S-S. A suspension wire 4 to which a coil 3 wound around a core 2 is attached is suspended from a casing 1, and position detectors 5 are provided near the lower tip of the suspension wire 4 on both sides of the wire. An example of the hanging wire 4 is shown in FIG. The suspension wire 4 shown in this drawing is not thread-like, but is a so-called plate-shaped suspension wire to which a core, for example, a hollow core 2 and a coil 3 are attached. This suspension wire is indicated by an arrow in FIG. However, this is sufficient for measuring the inclination angle.In order to simplify the description, in FIG. The mounting part is omitted. When the housing 1 is tilted and the position of the hanging wire 4 inside the housing changes, the position detector 5 detects this position change and outputs it electrically, and this output is used as a differential amplifier. The width is increased by a width filter 6 and sent to the coil 3.N pole 7 and south pole 8 of a permanent magnet are connected to both ends of the coil 3 with a slight gap between them.
Place them facing each other and fix them to the housing. Now, when the housing 1 is tilted at an angle θ, the position of the hanging wire 4 inside the housing changes, and the position detector detects and outputs the change in position near the lower end of the hanging wire 4, and this output current flows to the coil 3 and coils the coil. A magnetic field is formed in 3, so that this coil 3 repels on the north pole 7 side of the permanent magnet and attracts on the south pole 8 side [or attracts on the north pole 7 side and repulses on the south pole 8 side]. ],
The suspension line 4 moves to its original position within the casing 1 against the force of gravity perpendicular to the suspension line direction. Since the output amount is proportional to the tilt angle of the housing, that is, the tilt angle θ, it is displayed on the indicator 12 in the output voltage detection circuit. Since the inclinometer indicates the inclination angle as an output voltage value V _OUT , it is of course possible to provide an arithmetic circuit according to conventional electronic technology to convert this value into an angle value, and to display the latter value digitally or analogously. It is possible. However, the inclinometer constructed as described above is susceptible to changes in ambient temperature, i.e., the output voltage value changes due to changes in temperature, and therefore the measured data must be temperature-corrected afterwards. This is extremely inconvenient in practice. Figure 3 is a graph showing the relationship between voltage value and temperature in a certain inclinometer, where the X-axis represents the temperature (T°) and the Y-axis represents the output voltage error (△V _OUT ) expressed by the following formula: represents. △V _OUT = V′ _OUT −V _OUT (Here, V′ _OUT is the actual output voltage value of the inclinometer, and V _OUT is the true output voltage value that corresponds correctly to the inclination angle.) Like this However, all conventional inclinometers have a major drawback in that they are easily affected by temperature. Therefore, in the present invention, a thermistor 11 and a resistor _R2 are connected in series as a circuit for detecting the output voltage value corresponding to the inclination angle of the inclinometer, and a resistor R1 is connected in parallel to the thermistor 11 and a resistor R2 is connected in parallel to the thermistor ₁₁ . _R3
The purpose of this invention is to provide a circuit formed by connecting the following, so that the angle of inclination can be measured without substantial error at various temperatures. The present invention will be explained as follows with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the conventional inclinometer is equipped with a resistor R at the output end to detect the output from the inclinometer main body 9, and an indicator 10 detects the output voltage value (i.e. inclination angle). It was intended to display. In contrast, the present invention connects the thermistor TH11 and the resistor _R2 in series, connects the resistor _R1 in parallel with them, and further connects the resistor _R3 in series with them, as shown in Figure 5. The present invention is characterized in that a temperature correction (compensation) circuit configured as a circuit is provided as an output circuit. In other words, as a circuit for detecting the output voltage value of the inclinometer, a thermistor 11 and a resistor _R2 are connected in series, a resistor _R1 is connected in parallel with the circuit, and a resistor _R3 is connected in series with them. A circuit is constructed, and its output with respect to temperature is as shown in FIG. Therefore, the output voltage obtained from both ends of this circuit is as shown in Fig. 6, and it can be displayed on the indicator 12, or it can be converted into an analog or digital angle value according to the usual method, and then converted as appropriate. It is displayed using a suitable display means (not shown). The circuit shown in FIG. 5 will be explained in more detail. The resistance value of thermistor 11 is R _TH , and the resistance
When the combined resistance value of R ₁ , R ₂ and R ₃ is R _O , the change in resistance value due to temperature given to the combined resistance value R _O is expressed by the following equation. R _O =R ₁ (R ₂ +R _TH )/R ₁ +R ₂ +R _TH +R ₃ Therefore, R _TH has the value shown by the following equation. R _TH = R' _TH exp ^B(1/T-1/T ₀ ⁾ , where R' _TH is the resistance value at ambient temperature T _O (K), R _TH is the resistance value at ambient temperature T (K) , B is a thermistor constant expressed by the following equation. B=2.3026(logR _TH -logR' _TH )/1/T-1/T ₀ Thus, R _TH is a value that changes depending on the temperature. On the other hand, since the output voltage value of the inclinometer also changes depending on the temperature as mentioned above, the same amount of change as this change amount, but with the opposite sign, is given by R _TH , and the above output voltage value is This is intended to be a constant value that is independent of temperature changes. The error (△
The relationship between V _OUT ) and temperature (T°) is shown in the graph of FIG. As is clear from Fig. 6, by providing the temperature compensation circuit according to the present invention, the output voltage can be sufficiently compensated for the temperature, and therefore, this inclinometer can be put to practical use outdoors at various temperatures. It can be used for An example of experimental data regarding this is shown below. This experiment measured the error (indicated by angle value) when measuring an inclination angle of 40° at various temperatures, both with and without temperature correction according to the present invention. It was something to do.

[Table] As is clear from the above explanation, when installing a temperature compensation circuit according to the present invention, it is necessary to check the temperature characteristics of the output of the inclinometer and select and use a thermistor with characteristics that match these. Bye. Various types of thermistors with different temperature characteristics are currently available on the market, and an appropriate one can be selected from among them. The inclinometer according to the present invention can rotate 360° and can be used anywhere, and can be used as a kind of encoder. For example, as an example of the use of the present invention, when the inclinometer according to the present invention is incorporated into a light wave distance meter of a surveying instrument, horizontal distance and vertical distance can be calculated from the angle measurement value and the distance measurement value, ensuring that the permissible survey error is within the range. There are some that can be used as altitude angle encoders for surveying instruments because they can be stored inside the camera. In addition, the inclinometer of the present invention has an effective temperature correction circuit as described above, so it can display accurate angle measurement values (inclination) under various temperatures outdoors, so it can be used to measure angles (inclination) even outside a constant temperature room. This has the advantage that there is no need for a correction operation, and angle measurement (inclination angle) can be measured with high precision.

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of a conventional inclinometer, and Figure 2 is a diagram of the principle of a conventional inclinometer.
A schematic wiring diagram of the output detection circuit of the inclinometer shown in the figure, FIG. 3 is a graph showing the relationship between temperature and output voltage error in a conventional inclinometer, and FIG. 4 is a diagram of the temperature correction circuit of the inclinometer of the present invention. A graph showing the relationship between temperature and output voltage, FIG. 5 is a circuit diagram of an example of the output detection circuit of the inclinometer of the present invention, and FIG. 6 is a graph showing the output voltage of the inclinometer having the temperature correction circuit of the present invention. FIG. 7, a graph showing the relationship between error and temperature, is a schematic perspective view of an example of a suspension wire (a plate-shaped suspension wire) used in an inclinometer. 1...Inclinometer casing, 2... ... Core, 3 ... Coil, 4 ... Suspension wire (= plate-shaped suspension wire) 6 ... Width increaser,
7... N pole of magnet, 8... S pole of magnet, 9... Inclinometer body, 10... Indicator, 11... Thermistor, 12... Indicator or digital display.

Claims (1)

[Scope of utility model registration request] A coil is wound around the core, and this is suspended from the casing with a hanging wire to form a pendulum. Magnets with different polarities are placed opposite to each other at both ends of the coil and fixed to the casing, and a position detector is installed near the bottom end of the hanging wire. The position detector detects and outputs a change in position near the lower end of the suspension wire within the housing when the housing is tilted, and sends the output current to the coil, and this current flows. The thermistor 1 is configured such that the hanging wire moves to its original position within the housing due to the electromagnetic action between the coil and the magnet when the coil and the magnet move.
1 and a resistor _R2 are connected in series, a resistor _R1 is connected in parallel with the resistor R1, and a resistor _R3 is further connected in series with the circuit.