JPH0660822B2 - Displacement amount display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a sensor resistor whose resistance value changes according to the displacement level of a detected portion whose displacement amount is detected. The present invention relates to a displacement amount display device using an ammeter-type gauge that drives an indicator of an ammeter-type gauge by a value change and displays the above-mentioned displacement level by this indicator. Is what is used.

[Conventional technology]

Conventionally, in order to detect mechanical displacement, the variable resistor is operated based on this displacement amount, and based on the change in resistance value of this variable resistor, the pointer that moves the gauge is displayed to display the displacement amount. The device is generally used, but when the displacement amount fluctuates rapidly, the pointer vibrates greatly, which causes discomfort to the observer who sees the movement and makes it difficult to correctly recognize the displacement amount. was there.

For example, in a display device that displays the liquid level in a fuel tank of a vehicle, the liquid level may violently vibrate due to vehicle vibration while the vehicle is running. In such a case, the liquid level is displayed. If the pointer largely fluctuates, it may cause the driver of the vehicle to feel uncomfortable, and it may be difficult to accurately grasp the remaining fuel amount. For this reason, various devices have been developed. For example, a delay circuit is provided between a sensor and a display portion for displaying a signal from the sensor, and the delay operation of the delay circuit is selectively switched. Thus, a device has been developed in which a large delay operation is applied when there is a relatively large liquid level fluctuation such as when the vehicle is running so that the pointer does not vibrate due to a sudden liquid level fluctuation. For example, Japanese Utility Model Publication No. 59-37699 discloses the circuit shown in FIG. 2, in which a signal from the liquid level sensor 71 is transmitted to a thickener 73 via a delay circuit 74. The signal is amplified by this amplifier and ammeter-type meter 72
Is to be driven. Then, by the signal from the key switch 2, the liquid level sensor 7
When a signal is output from 1, the preset circuit 75 reduces the delay operation of the delay circuit 74 for a predetermined time from that time, thereby quickly transmitting the liquid level captured by the liquid level sensor to the meter 72 for display. On the other hand, in the case where the liquid level is relatively variable after a predetermined time has elapsed since the key switch 2 was turned on, the preset circuit 75 increases the delay operation of the delay circuit 74 to increase the liquid level. It is considered that the meter 72 follows this and the pointer is not abruptly moved even if the level suddenly changes.

[Problems to be solved by the invention]

However, this circuit basically provides a delay circuit between the liquid level sensor and the meter to switch the delay operation of this delay circuit. Therefore, even if you want to quickly display the liquid level on the basis of the signal from the liquid level sensor, it is unavoidable that a certain amount of delay acts, for example immediately after turning on the key switch and immediately after that. Could not display the liquid level in the gasoline tank. That is, even in such a case, only a circuit configuration capable of performing a delay operation to some extent could be configured. That is, in the configuration in which the delay time of the delay circuit is switched, the configuration is such that the charging of the capacitor in the delay circuit is switched from quick charging to slow charging. It is impossible to make the value extremely large because the circuit becomes large in size. Therefore, even when the rapid charging is performed and the delay operation of the delay circuit is small, the delay operation is delayed to some extent, which makes it difficult to quickly display the signal of the liquid level sensor on the meter. .

Therefore, according to the present invention, the pointer is immediately moved according to the displacement level of the detected part, and when the displacement level is desired to be displayed, it is promptly displayed without activating unnecessary delay operation, and as a result, the display device is visually inspected. It is possible to promptly recognize the displacement amount of the detected part to the person who is operating, and if the displacement amount of the detected part fluctuates significantly due to disturbance in a short time, immediately inform the change to the pointer. No
Provided is a displacement amount display device capable of eliminating the adverse effects that an observer viewing the display device feels uncomfortable and it becomes difficult to accurately grasp the displacement amount of a detected portion by reducing the touch of a pointer. The purpose is to do.

[Structure of Invention]

The present invention has been made to achieve the above object, and a sensor resistor whose resistance value changes according to a displacement amount of a detected portion, and a first amplifier circuit for amplifying a voltage at one end of the sensor resistor. And the output stage transistor driven by the output signal from the first amplifier circuit, and the position at which the pointer is displaced is changed according to the amount of current connected to the output stage transistor and flowing through the output stage transistor. Display means, switch means for connecting a power source to the display means, and a capacitor charged to a voltage substantially equal to the voltage at one end of the sensor resistor, and in cooperation with this capacitor A potential follow-up circuit having a resistance in which a time constant is set, and a voltage at one end of a capacitor in the potential follow-up circuit is amplified, and the amplified signal is output to the output stage transistor. The amplifier circuit includes a two-amplifier circuit and a timer circuit that measures a time after the switching means is turned on and outputs a timer signal indicating that after a predetermined time has elapsed. The potential tracking circuit outputs a timer signal from the timer circuit. Until the time of outputting, the time constant is kept small, and the output signal of the first amplifier circuit is allowed to be applied to the output stage transistor. When the timer signal is output from the timer circuit, the time constant is reduced. It is provided with a technical means of changing and increasing the signal and switching the signal applied to the output stage transistor from the first amplifier circuit to the output signal of the second amplifier circuit.

The present invention will be described in relation to the present embodiment. The voltage appearing at one end of the sensor resistor is controlled by the first amplifier circuit (OP
1) The signal is amplified via 1) and this signal is given to the output stage transistors (Tr _10, Tr ₁₁ ), and the display means connected to the collector side of the output stage transistors quickly changes the resistance value of the sensor resistor. Based on this, the deflection of the pointer is caused to promptly display the displacement amount of the detected portion.

Further, during this period, the capacitor C ₁ in the potential follow-up circuit (4) is rapidly charged based on the signal from the timer circuit (6) until the voltage of the capacitor becomes substantially equal to the voltage at one end of the sensor resistor. Charge it. After a lapse of a predetermined time such that the rapid charging is completed, the capacitor is gradually charged and discharged, and the follow-up operation is performed so that the voltage becomes equal to the voltage appearing at one end of the sensor resistor. Also, after quick charging is performed by the timer circuit 6,
A second amplifier circuit (OP) that nullifies the output signal of the first amplifier circuit (OP1) and amplifies the voltage at one end of the capacitor.
Since the signal of 2) is validated, this time the second amplifier circuit (O
The signal of P2) is output stage transistor (Tr ₁₀ , Tr
₁₁ ). Therefore, the display means (8) is controlled based on the voltage at one end of the capacitor that follows the voltage at one end of the sensor resistor (RS) with a gentle time constant.

[Action]

With the above configuration, after a lapse of a predetermined time after the switch means for turning on the display means (8) is turned on, the display means (8) is controlled by the voltage at one end of the capacitor that charges and discharges with a slow time constant. Therefore, even if the detected portion is largely displaced and the sensor resistance value changes abruptly, the voltage at one end of the capacitor does not change so much, so that the deflection of the pointer of the display means does not change greatly. Therefore, the pointer does not shake suddenly and is easy to see.

Immediately after the switch means is turned on, the voltage at one end of the sensor resistor is directly transmitted to the display means (8) through the first amplifier circuit (OP1), so that there is no display delay, and therefore, immediately after the switch is turned on. The displacement amount at that time can be grasped.

〔The invention's effect〕

As described above, in the present invention, since the displacement amount can be displayed by the display means immediately after the switch means is turned on without any time delay, an observer who visually observes the display means can immediately grasp the information. No discomfort. Further, even if the displacement of the detected portion is drastically changed due to the disturbance, the indicator is driven by the voltage at one end of the capacitor after a while after the switch is turned on, so that the pointer does not suddenly change. The effect is that the displacement level of the detected portion can be accurately grasped.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a battery, 2 is a key switch, 3 is a sensor portion, and a sensor resistor R _s and a fixed resistor R _o are provided. 4 is a potential follow-up circuit, a comparator CP ₁ that one end of the voltage of the sensor resistor R _s is in this, by controlling the transistor Tr ₁ by comparing the voltage of the capacitor C _1, to control the charging and discharging of the capacitor Is provided.
R ₁ and R ₂ are resistors, and R ₃ and R ₄ are resistors for charging the capacitor C ₁ . Reference numeral 6 is a timer circuit, and a signal from the timer circuit 6 controls the transistor Tr ₃ via the resistor R ₁₂ and similarly the transistor Tr ₆ via the resistor R ₁₈ . Then, when the transistor Tr ₃ is turned on, the transistor Tr ₄ is turned on.
However, the capacitor C ₁ is designed to be rapidly charged by the current flowing through the battery 1, the key switch 2, the transistor Tr ₄ , and the resistor R ₁₅ .

The timer circuit 6 is a circuit that measures the time after the key switch 2 is turned on and outputs a timer signal indicating that the time has elapsed after a predetermined time has passed. In this embodiment, the resistors R _{7 to} R are used.
₁₁ has a capacitor C with the charging current from the battery 1.
_When the voltage of ₂ rises, the comparator CP ₂ outputs a low-level signal to turn off the transistors Tr ₃ and Tr ₆ . As a result, the rapid charging of the capacitor C ₁ is stopped, and the capacitor C ₁ has the resistors R ₃ and R ₄
The charging through the transistor Tr ₁ and the discharging through the transistor Tr ₁ are repeated, and a voltage substantially the same as the voltage V _RS at one end of the resistor R _s is controlled to appear as V _C1 .

When the transistor Tr ₆ turns off, the transistor Tr ₅
There turned ON, the first amplifier circuit OP1 via the diode _{D 2}
Output is invalid. On the contrary, when the transistor Tr ₃ is ON, the signal of the second amplifier circuit OP2 is invalidated via the diode D ₁ . Reference numeral 8 is an ammeter-type meter which serves as a display means. Tr ₁₀ and Tr ₁₁ are output stage transistors.

The operation will be described below. When the key switch 2 is turned on, the voltage of the capacitor C ₂ is charged with the time constant C ₂ × R ₉ . The voltage at one end of the capacitor C ₂ is the reference voltage V
CC × R ₈ / (R ₇ + R ₈ ) ... However, the output of the comparator CP2 is at a high level until VCC reaches the voltage of the constant voltage given to the terminal T _c .
The transistors Tr _3, Tr ₄ , and Tr ₆ are on. Therefore, the transistor Tr ₅ is turned OFF, and the output of the second amplifier circuit OP2 is Low level.

Therefore, the output of the sensor resistance R _s whose resistance value changes according to the fuel liquid level (V _RS ) = R _s / (R _o + R _s ) ×
VCC is amplified by the first amplifier circuit OP1 with an amplification factor (1 + R
₁₆ / R ₁₇ ). Therefore, the displacement amount detected by the sensor resistor R _s is transmitted to the display means 8 without any time delay, and the pointer is immediately driven.

At the same time, the capacitor C ₁ is connected to the O of the transistor Tr ₄ .
It is charged by N with a fast time constant C ₁ × R ₁₅ . When the voltage of the capacitor C ₁ becomes equal to the voltage V _RS at one end of the sensor resistor R _S , the output of the comparator CP1 becomes Low.
The level is switched to the High level, and the transistors Tr ₁ and Tr ₂ are both turned on. This turns off the transistors Tr ₃ and Tr ₄ , and then the capacitor C ₁
Is slowly charged by a current flowing through the resistors R ₄ and R ₃ , and when the transistor Tr ₁ is turned on, the resistor R
It is slowly discharged via ₄ .

After that, that is, after a predetermined time has passed since the key switch was turned on, the voltage of the capacitor C ₂ is changed to the reference voltage (R ₈
/ (R ₇ + R ₈ ) × VCC), the output of the comparator CP2 thereafter becomes the Low level. Therefore, the transistors Tr ₃ and Tr ₄ are turned off, and even if the comparator CP1
Outputs a Low-level signal from the transistor Tr ₂
Even if FF is performed, the capacitor C ₁ will not be rapidly charged. Therefore, the capacitor C ₁ has a slow time constant C
Discharge or charge is repeated at ₁ × R ₄ .

Further, the output of the comparator CP2 becomes Low level, so that the transistor Tr ₆ is turned off, and as a result, the transistor Tr ₅ is turned on. Therefore, the output of the first amplifier circuit OP1 is invalidated, and the display means 8 is controlled by the output of the second amplifier circuit OP2. That is, when the transistor Tr ₃ is turned off by inverting the output of the comparator CP2 to the Low level, there is no current for setting the output of the second amplifier circuit via the diode D ₁ to the Low level, and thus the voltage V _C1 of the capacitor C ₁ is The signal is amplified by the second amplifier circuit OP2 with an amplification factor (1 + R ₅ / R ₆ ), and the amplified signal is added to the output-stage transistors Tr _{10 and} Tr ₁₁ , and current is supplied to the display means 8 so that the capacitor C ₁ is supplied. The deflection of the pointer occurs depending on the voltage. Therefore, for example, the fuel liquid level vibrates violently due to the vibration of the vehicle, and therefore the float for detecting the fuel liquid level violently moves up and down, and the resistance value of the variable resistor interlocked with the float, that is, the sensor resistance R _S fluctuates greatly. Even if it does, the voltage V _C1 of the capacitor C ₁ gradually rises or falls. That is, the time constant C ₁
Since the voltage of the capacitor C ₁ changes gently with the delay operation of × R _4, the display means 8 controlled by this voltage 8
Also, the pointer does not abruptly move, the pointer of the meter is smoothly displaced, and does not abruptly change.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, and FIG. 2 is an electric circuit diagram of a conventional circuit. 1 ... Battery, 2 ... Key switch, 4 ... Potential tracking circuit, 6 ... Timer circuit, 8 ... Display means, OP1 ...
First amplifier circuit, OP2 ... Second amplifier circuit, Tr _10, T
r ₁₁ ... Output stage transistor.

Claims (1)

[Claims] 1. A sensor resistor whose resistance value changes according to the amount of displacement of a detected portion, a first amplifier circuit for amplifying a voltage at one end of the sensor resistor, and an output signal from the first amplifier circuit. Connected to the output stage transistor, and a display unit connected to the output stage transistor for changing the position where the pointer is displaced according to the amount of current flowing through the output stage transistor, and a power source connected to the display unit. Potential follower having a switch means and a capacitor charged to a voltage substantially equal to the voltage at one end of the sensor resistor, and a resistor having a time constant set in cooperation with the capacitor. A circuit, a second amplifier circuit that amplifies a voltage at one end of a capacitor in the potential tracking circuit, and outputs the amplified signal to the output stage transistor; And a timer circuit that outputs a timer signal indicating that after a predetermined time has elapsed, the potential follow-up circuit is configured to operate at the time until the timer signal is output from the timer circuit. The constant is kept small and the output signal of the first amplifier circuit is allowed to be given to the output stage transistor, and when the timer signal is output from the timer circuit, the time constant is changed to be increased and the output stage is increased. The signal applied to the transistor is the first
A displacement amount display device characterized by switching from an amplifier circuit to an output signal of the second amplifier circuit.