JPH1038618A - Measured value displaying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deflection of the pointer of a measured value displaying device caused by the fluctuation of measured values by constituting the device so that the device can control the permission and inhibition of reading of the measured values to an arithmetic means after a prescribed period of time elapses from the start of measured value indicating operations. SOLUTION: After various kinds of initializing operations are carried out, a timer circuit 25 is reset and started. When the time indicated by the circuit 25 falls within the period from time T1 when a fixed period of time has elapsed from the start of the circuit 25 to time T2 when a fixed period of time T1 has elapsed further from the time T1, the output signal of a fuel gauge fetched last time is again given to an arithmetic means 27a. It is preferable to respectively set the time T1 and T2 at about 1.7 seconds and 7 seconds. When the time indicated by the circuit 25 does not fall within the period, the inclined angle of the pointer of a measured value displaying device is calculated by fetching the current output signal of the fuel gauge from an A/D converter 30. When the time indicated by the circuit 25 falls within a period after the time T2 has elapsed, a relevant filter constant is read out from a filter constant setting section 24 and, when the time does not fall within the period, another relevant filter constant is read out. The filter constant is substituted into a calculating formula held by the arithmetic means 27a and averaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in, for example,
The present invention relates to a measurement value display device that can reliably suppress the deflection of a pointer that may occur when giving an instruction in accordance with a measurement value.

[0002]

2. Description of the Related Art FIG. 4 is a circuit diagram showing a configuration of a conventional measured value display device 100 used for a fuel gauge. In the figure, reference numeral 1 denotes a voltage applied to the measured value display device 100.
The applied voltage adjusting resistors for lowering the ignition voltage from 3.5 V to about 9 V, 2, 3 and 4 are resistors for adjusting the value of the current flowing through the cross coil 5. The resistance 2 and the resistance 3 are connected in series, and a series circuit of the resistance 2 and the resistance 3 and the resistance 4
Are connected in parallel to the cross coil. The resistance 3
Are configured as variable resistors. 5 is a first cross coil, 7 is a second cross coil, and 8 is a third cross coil. The second cross coil 7 and the third cross coil 8 are connected in series, and the second cross coil 7 and the third cross coil 8
A liquid level sensor 6 for detecting the remaining amount of fuel is connected in parallel to the series circuit. The resistance value of the liquid level sensor 6 changes according to the liquid level of the fuel.

Next, the operation will be described. An ignition voltage is applied to the measured value display device 100, and the output of the liquid level sensor 6 directly controls the current value flowing through the first cross coil 5, the second cross coil 7, and the third cross coil 8. Then, the remaining amount of fuel is instructed in accordance with the measured value of the liquid level. In this case, if the liquid level in the fuel tank fluctuates greatly due to vibration, the fluctuation in the liquid level will appear as a deflection of the pointer that directly indicates the remaining fuel level, and the response will be made by the damper mechanism using silicon oil etc. By slowing the movement, the deflection of the pointer is suppressed.

[0004]

Since the conventional measured value display device is configured as described above, the speed of response is fixed particularly when applied to a fuel gauge for indicating the remaining amount of fuel. Therefore, it takes a long time to perform the adjustment work when performing the instruction adjustment, or the ignition switch is turned on immediately after refueling at the gas station, and the instruction of the pointer when the vehicle starts suddenly does not show a true value.

[0005] In addition, even when the engine is started while making a sharp turn after starting the engine, the fuel in the fuel tank moves to one side of the tank due to centrifugal force. Therefore, there is a problem that even if the response is delayed by the damper mechanism or the electric response is adjusted, the deflection of the pointer cannot be suppressed, and the pointer indicating the remaining amount does not indicate a true value. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a measurement value display device capable of reliably suppressing the deflection of a pointer due to a change in a measurement value.

[0007]

According to a first aspect of the present invention, there is provided a measurement value display device which reads a measurement value input terminal to which a measurement value of a physical quantity is input and a measurement value input from the measurement value input terminal. A calculating means for calculating and calculating a display control amount corresponding to the measured value, and a measured value indicating unit for performing an instruction operation based on the display control amount calculated by the calculating means and giving an instruction according to the measured value; A measurement value read control unit that controls permission and prohibition of reading of the measurement value to the arithmetic unit according to a predetermined time elapse from a start time of the measurement value instruction operation input from the measurement value input terminal; It is provided with.

According to a second aspect of the present invention, there is provided a measured value display control means for controlling reading of the measured value into the arithmetic means in accordance with a lapse of time after the ignition switch is turned on. It is provided with.

According to a third aspect of the present invention, the measured value display device reads the measured value into the arithmetic means by the second time after the first time has elapsed since the ignition switch was turned on. The apparatus is provided with a measurement value reading control means for prohibiting the period until the elapse.

According to a fourth aspect of the present invention, there is provided the measured value display device, wherein the ignition switch is operated to the ON state, and the first
In the period until the time elapses, the responsiveness at the time of giving an instruction in accordance with the measurement value is increased, and further, the responsiveness control means for reducing the responsiveness after the second time has elapsed is provided. Things.

According to a fifth aspect of the present invention, there is provided a measured value display device, which changes a time constant of a signal processing filter for digitally processing a measured value to thereby improve responsiveness when an instruction corresponding to the measured value is given. This is provided with responsiveness control means for controlling.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a measured value display device according to the first embodiment applied to a fuel gauge.
In the figure, 21 is a measured value display device, 22 is a custom I
Although it is constituted by C, it can also be constituted by a microcomputer. An EEPR 23 stores instruction characteristic data for digitally processing a fuel gauge output signal (measured value) output from a fuel gauge (not shown).
OM and 24 are filter constant setting units for storing filter constants F1 and F2 (F1 <F2) for determining a time constant at the time of averaging processing described later. A timer circuit 26 detects the passage of time, and is a RAM having a data area for storing the A / D converted fuel gauge output signal. 27
Is a data processing circuit (responsiveness control means) which performs processing such as averaging processing and PWM calculation, and calculates and calculates a display control amount corresponding to the fuel gauge output signal;
A measurement value reading control unit 27b for permitting or prohibiting the reading of the fuel gauge output signal to the calculation unit 27a in accordance with the lapse of the time detected by the timer circuit 25 is provided. 28 is a filter constant setting unit 24, a timer circuit 2
5, a logic circuit unit having a RAM 26, a data processing circuit 27, and the like. 29 is an ignition switch detection circuit for detecting the ON state and the OFF state of the ignition switch based on the ignition switch output signal.
Reference numeral a denotes an ignition switch signal input terminal for inputting an ignition switch output signal to the ignition switch detection circuit 29. Reference numeral 30 denotes an A / D converter for A / D converting the fuel gauge output signal, and 30a denotes an A / D converter 3.
A measurement value input terminal for inputting a fuel gauge output signal to 0.

Reference numeral 41 denotes a PWM circuit (measured value display unit) for generating a PWM modulation signal based on a display control amount corresponding to the fuel gauge output signal output from the data processing circuit 27, and reference numeral 42 denotes a signal output from the PWM circuit 41. A movement driver (measurement value display unit) 43 for generating a movement drive current based on the PWM modulation signal, and a cross-coil movement (measurement value display unit) 43 to which the movement drive current generated by the movement driver 42 is supplied. By driving a pointer (not shown), the remaining amount of fuel is instructed according to the fuel gauge output signal. Note that the PWM circuit 41 and the movement driver 42
And a cross coil movement 43 constitute a measurement value indicating unit.

Next, the operation will be described. FIG. 2 is a timing chart showing the operation of the measurement value display device 21. As shown in (c) of FIG. 2, the measured value display device 21 performs the AD operation for a period of time T1 from the time when the ignition switch is turned on to change the output signal of the ignition switch to the “H” level. Allow reading of the converted fuel gauge output signal. This time T1 is preferably, for example, about 1.7 seconds. Further, reading of the A / D converted fuel gauge output signal is prohibited after the time T1 has elapsed and until the time T3 has further elapsed. In this case, the time T2 is the sum of the time T1 and the time T3, and it is preferable that the time T2 is about 7 sec from the time when the ignition switch output signal changes to the “H” level until the time T3 elapses. After the time T3 has elapsed, reading of the fuel gauge output signal is permitted. Further, the time constant when the remaining amount instruction is performed until the time T1 elapses is set to be smaller than the time constant after the time T3 elapses.

FIG. 3 is a flowchart showing the operation of the data processing circuit 27 for realizing the operation shown in the timing chart of FIG. According to this flowchart,
First, various initial settings are performed (step ST1).
The timer circuit 25 is reset and started (step ST2). This timer circuit 25 can be realized by hardware or software. Next, it is determined whether or not the time t indicated by the timer circuit 25 is during a period from when the time T1 has elapsed to when the time T2 has elapsed (step ST3). As a result, when it is determined that the time t is included in the period, the fuel gauge output signal captured last time is again provided to the calculating means 27a (step ST4). As a result, the calculating means 27a calculates the indicated angle (converts the A / D converted signal into the indicated angle data) based on the previous fuel gauge output signal (step ST5). On the other hand, if it is determined in step ST3 that the time t is not included in the period, the A / D converter 30
(Step ST6), and calculates the indicated angle (converts the A / D converted signal into the indicated angle data) based on the fuel meter output signal (Step ST6). Step ST5). Therefore, step S
T4 and step ST6 correspond to the measurement value reading control means 27b.

Next, it is determined whether or not the time t indicated by the timer circuit 25 is included in a period after the time T2 has elapsed (step ST7). As a result, when it is determined that the period is included, the filter constant F2 stored in the filter constant setting unit 24 in the custom IC is read and the filter constant is set to F2 (step ST8). On the other hand, when it is determined in step ST7 that the period is not included in the period, the filter constant F1 stored in the filter constant setting section 24 is read out and the filter constant is set to F1 (step ST8). The filter constant is substituted into the designated angle calculation formula in the calculation means 27a in the data processing circuit 27, and is subjected to an averaging process (step ST9). The designated angle calculation formula is shown in the following formula (1). _{D n = D n-1 +} (d n -D n-1) / N ··· (1) where, N is the filter constant F1 selected from the filter constant setting unit 24 (for example, F1 = 8), F2 (For example, F
2 = 1024), where D _n is the current designated angle and D _n−1
Instructions angle of the previous, d _n is the instruction angle corresponding to the currently input fuel sensor signal. Note that N is a small value (F
In the case of 1), the change amount from the previous designated angle to the present designated angle is large, and when N is a large value (F2), the change amount from the previous designated angle to the present designated angle is small. Become. That is, when N is small (F1), the response is fast, and when N is large (F2), the response is slow. Then, the processing result is output (step ST1).
1). An operation corresponding to the pulse width modulation performed by the PWM circuit 41 is performed on the processing result, and the operation result is output (step ST12). Further, it is determined whether or not the time t indicated by the timer circuit 25 at this time has reached 52.5 msec. If it has not reached 52.5 msec, time waiting is performed until the time t reaches 52.5 msec (step ST13). When the time reaches .5 msec, the process returns to step ST2.

As described above, according to the measured value display device of the first embodiment, the time T3 elapses after the time T1 has elapsed by the steps ST4 and ST6 corresponding to the measured value reading control means 27b. During this period, a new fuel gauge output signal is not captured, and the previously captured fuel gauge output signal is used again to calculate the designated angle according to the fuel gauge output signal by the calculating means, and to calculate the designated angle with the previous one. Since the same designated angle is output, even if the fuel level during the period greatly changes due to sudden turning or sudden start of the vehicle, it is possible to reliably suppress the deflection of the pointer.

In the embodiment described above,
A reading prohibition period for prohibiting reading of the fuel gauge output signal is provided until the signal immediately after the ignition switch is turned on and the ignition switch output signal changes to the “H” level is stabilized (about 500 msec). It is good also as comprising and after that it is the above-mentioned content.

[0019]

As described above, according to the first aspect of the present invention, a measured value input terminal to which a measured value of a physical quantity is input;
A measuring means for reading a measurement value input from the measurement value input terminal and calculating and calculating a display control amount corresponding to the measurement value; and performing an instructing operation based on the display control amount calculated by the calculation means. A measurement value instructing unit for giving an instruction in accordance with the measurement value, and reading of the measurement value into the arithmetic means according to a predetermined time lapse from the start of the operation of instructing the measurement value input from the measurement value input terminal And the measured value reading control means for controlling the permission and prohibition of the hand, the effect of reliably suppressing the deflection of the pointer due to the fluctuation of the measured value generated when a predetermined time has elapsed from the start point. is there.

According to the second aspect of the present invention, there is provided a measurement value reading control means for controlling the reading of the measurement value to the arithmetic means in accordance with the lapse of time after the ignition switch is turned on. Therefore, there is an effect that it is possible to reliably suppress the wobble of the hands due to the fluctuation of the measured value that occurs when a predetermined time has elapsed since the ignition switch was turned on.

According to the third aspect of the present invention, the reading of the measured value into the arithmetic means is performed during a period from when the first time elapses after the ignition switch is turned on to when the second time elapses. And the prohibition of the measurement value reading control means, so that it is ensured that the pointer swings due to the fluctuation of the measurement value occurring during the period from when the first time elapses to when the second time elapses. There is an effect that can be suppressed.

According to the fourth aspect of the present invention, the responsiveness at the time of giving an instruction in accordance with the measured value is increased during the period from when the ignition switch is turned on to when the first time elapses, and After the elapse of the second time, the responsiveness control means for reducing the responsiveness is provided, so during the period until the first time elapses, an instruction according to the measured value is quickly performed, There is an effect that an instruction when the ignition switch is operated to the ON state can indicate a true value according to the measured value.

According to the fifth aspect of the present invention, the time constant of the signal processing filter for digitally processing the measured value is changed to control the responsiveness at the time of giving an instruction according to the measured value. Since it was configured to have control means,
There is an effect that accurate responsiveness can be controlled by digital processing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a measurement value display device according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing an operation of the measured value display device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the data processing circuit of the measurement value display device according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a conventional measurement value display device.

[Explanation of symbols]

 Reference Signs List 21 measurement value display device 25 timer circuit 27 data processing circuit (response control means) 27a calculation means 27b measurement value reading control means 30a measurement value input terminal 41 PWM circuit (measurement value display section) 42 movement driver (measurement value display section) 43 Cross Coil Movement (Measurement Value Display)

Claims (5)

[Claims] 1. A measurement value input terminal to which a measurement value of a physical quantity is input, and a calculation means for reading a measurement value input from the measurement value input terminal and calculating and calculating a display control amount corresponding to the measurement value; A measurement value instructing unit that performs an instruction operation based on the display control amount calculated by the arithmetic unit and performs an instruction according to the measurement value; and a start of the measurement value instruction operation input from the measurement value input terminal. A measurement value display device comprising: a measurement value reading control unit that controls permission and prohibition of reading of the measurement value into the calculation unit in accordance with a lapse of a predetermined time from a time point. 2. The measurement device according to claim 1, wherein the measurement value reading control means controls reading of the measurement value into the calculation means in accordance with a lapse of time after an ignition switch is turned on. Value display device. 3. The measured value reading control means reads the measured value into the arithmetic means during a period from when a first time elapses after an ignition switch is turned on to when a second time elapses. 3. The method according to claim 2, which is prohibited.
The measured value display device as described. 4. The responsiveness of giving an instruction according to a measured value during a period until the first time elapses after the ignition switch is turned on and the second time elapses after the second time elapses 4. The measurement value display device according to claim 3, further comprising a responsiveness control unit that reduces the responsiveness. 5. The responsiveness control means controls the responsiveness when giving an instruction in accordance with the measured value by changing a time constant of a signal processing filter for digitally processing the measured value. The measured value display device according to claim 4, wherein