WO1998004888A1 - Measured value indicator system - Google Patents

Measured value indicator system

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Publication number
WO1998004888A1
WO1998004888A1 PCT/JP1997/002604 JP9702604W WO1998004888A1 WO 1998004888 A1 WO1998004888 A1 WO 1998004888A1 JP 9702604 W JP9702604 W JP 9702604W WO 1998004888 A1 WO1998004888 A1 WO 1998004888A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
measured value
indication
response
means
indicator system
Prior art date
Application number
PCT/JP1997/002604
Other languages
French (fr)
Inventor
Masakazu Kobayashi
Kazumasa Watanabe
Kazuo Takahashi
Original Assignee
Kansei Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/42Devices characterised by the use of electric or magnetic means
    • G01P3/44Devices characterised by the use of electric or magnetic means for measuring angular speed
    • G01P3/48Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
    • G01P3/481Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
    • G01P3/489Digital circuits therefor
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D18/00Testing or calibrating of apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D3/00Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/02Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation
    • G01D3/022Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation having an ideal characteristic, map or correction data stored in a digital memory
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm
    • G01F23/0061Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm characterised by the level signal processing means
    • G01F23/0069Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm characterised by the level signal processing means particular electronic circuits for digital processing equipment
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R7/00Instruments capable of converting two or more currents or voltages into a single mechanical displacement
    • G01R7/04Instruments capable of converting two or more currents or voltages into a single mechanical displacement for forming a quotient
    • G01R7/06Instruments capable of converting two or more currents or voltages into a single mechanical displacement for forming a quotient moving-iron type

Abstract

A measured value indicator system comprises an arithmetic means for reading the measured value inputted from a measured value inputting terminal to acquire an indication control quantity corresponding to the measured value, a measured value indication unit for making an indication corresponding to said measured value on the basis of the indication control quantity acquired by said arithmetic means and a measured value reading control means for controlling the permission and inhibition of said measured value inputted from said measured value inputting terminal in accordance with passage of a predetermined time from a starting timing of indication of said measured value.

Description

DESCRIPTION

MEASURED VALUE INDICATOR SYSTEM

TECHNICAL FIELD

The present invention relates to a measured value indicator system capable of easily and accurately adjusting the response for a measured value when it is indicated, and also of surely suppressing the swing of an indicating needle. BACKGROUND ART

Fig. 1 is a circuit diagram showing a configuration of a conventional measured value indicator system used for a fuel meter. In Fig. 1, reference numeral 1 denotes an applied voltage adjusting resistor for lowering the voltage applied to a measured value indicator system 100 from the ignition voltage of 13.5 V to about 9 V. Reference numerals 2, 3 and 4 denote resistors for adjusting the value of the current flowing through a crossing coil 5. The resistors 2 and 3 are connected in series with each other. The resistor and the series circuit of the resistors 2 and 3 are connected in parallel to the crossing coil 5. The resistor 3 is a valuable resistor. Reference numerals 5, 7 and 8 denote a first, a second and a third crossing coil, respectively. The second crossing coil 7 and the third crossing coil 8 are connected in series . A liquid face sensor 6 for detecting a fuel level or remaining fuel amount is connected to the series circuit composed of the second crossing coil 7 and the third crossing coil 8. This liquid face sensor 6 provides a resistance varying in accordance with the liquid face level of the fuel.

An explanation will be given of the operation of the measured value indicator system 100.

When an ignition voltage is applied to the measured value indicator system 100, the output from the liquid face sensor 6 directly controls the currents flowing through the first, second and third crossing coils 5, 6 and 7 to indicate the fuel level according to the measured value of the liquid face level. In this case, when the liquid face in a fuel tank varies greatly and abruptly owing to vibration, the valuation of the liquid face directly leads to the swing of an indicator needle for indicating the fuel level. Therefore, it is intended to suppress the swing of the indicator needle by retarding the response of the needle by a damper mechanism using silicon oil, etc.

In the conventional measured value indicator system constructed as described above, when it is applied to the fuel meter for indicating fuel level, a time of work for adjusting the indication is required because of fixed speed of response. Also when fast driving-away is made by turning on an ignition switch immediately after refueling at a gasoline stand, the indicator needle may not indicate a real value .

Further, when driving-away is made by snap turn after engine start, the fuel in the fuel tank will move toward one end thereof by centrifugal force. Therefore, retardation of the response of the damper mechanism and electric adjustment thereof cannot suppress the swing the of the indicator needle so that the indicator needle does not indicate a real value of the fuel level .

Fig. 2 is a block diagram showing the configuration for performing checking and indication adjustment of the indication result of the conventional measured value indicator system used as a fuel meter. In Fig. 2, reference numeral 201 denotes a crossing coil movement which is a needle driving mechanism for indicating the fuel level and includes a pair of X and Y coils arranged to cross at an angle of 90° each other and an indicating movable magnet arranged rotatably under the magnetic field by these coils. In order to prevent the variation of the liquid face in the fuel tank due to vibration from being directly given to the indicating needle, this measured value indicator system intends to retard the response using the damper mechanism of silicon oil. Reference numeral 202 denotes an indication checking/adjusting device for connecting a stabilized Vcc power source to one coil of the crossing coil movement 201 and supplying a fuel sensor signal indicative of the fuel level measured by the fuel sensor (not shown) to the other coil.

An explanation will be given of the operation of the measured value indicator system of Fig. 2. Fig. 3 is a flowchart showing the processing steps of indication adjustment for the measured value indicator. The indication adjustment for the measured value indicator system is carried out during the test process before its shipping. In the flowchart of Fig. 3, first, a power source is turned on (step ST21). A fuel sensor signal set for a first indication test value is supplied to the crossing coil movement 201 (step ST22). Five or longer minutes is caused to elapse until the indication of the needle is shifted to be stable on the first indication test value (step ST23). This is because owing to retardation of the response of the crossing coil movement 201 by the damper mechanism of e.g. silicone oil, it takes a time until the needle indication becomes stable. When five or longer minutes has elapsed, it is determined whether the indication state is normal (step ST24). When it is determined "not good", the indication is adjusted (step ST25) to return to step ST22. On the other hand, in step ST24, when it is determined "good", the indication test value is continuously altered (step ST27). Step ST23, step ST24 and step ST26 are repeated until the final indication test value. In step ST26, when it is decided that test is completed for the final indication value, the power source to which the crossing coil movement 202 is connected is cut off (step ST28).

In the conventional measured value indicator system of Fig. 2 constructed as described above, when indication test or indication adjustment is performed, elapse of several minutes is required until the indication of the needle becomes stable. For this reason, it takes a relatively long time to perform the indication test or indication adjustment of the measured value indicator.

Fig. 4 is a block diagram showing the configuration of a conventional measured value indicator system for indicating the rpm of a vehicle engine. In Fig. 4, reference numeral 301 denotes a crossing coil movement composed of a first fixed coil 301a and a second fixed coil 301b which serves as a needle driving mechanism. Reference numeral 302 denotes a driver circuit for supplying to the first fixed coil 301a a driving current corresponding to a voltage signal generated in a sinusoidal (sin) function generating circuit 304. Reference numeral 303 denotes a driver circuit for supplying to the second fixed coil 301b a driving current corresponding to a voltage signal generated in a cosine function generating circuit 305. Reference numeral 304 denotes the sinusoidal function generating circuit for generating a voltage signal having a sin waveform. Reference numeral 305 denotes the cosine function generating circuit for generating a voltage signal having a cosine waveform. Reference numeral 306 denotes an integrating circuit composed of a resistor R and a capacitor C. Reference numeral 307 denotes a monostable multivibrator circuit. Reference numeral 308 denotes a waveform shaping circuit for shaping the waveform of a pulse signal inputted at a period according to the rpm of the vehicle engine. An explanation will be given of the measured value indicator system shown in Fig. 4.

An input pulse signal at the period corresponding to the rpm of the engine taken out from an ignition coil or engine controller is waveform-shaped by the waveform shaping circuit 308. The pulse signal thus waveform-shaped is supplied to the monostable multivibrator 307. In the monostable multivibrator circuit 307, the edge of the input pulse signal waveform-shaped is detected so that a pulse signal having a certain pulse width is supplied to the integrating circuit 306. In the integrating circuit 306, the above pulse signal having a certain pulse width is integrated into a DC current which is in turn supplied to the sinusoidal function generating circuit 304 and the cosine generating circuit 305. In the sinusoidal function generating circuit 304, the above DC current is converted into a voltage signal varying in the form of a sine wave. In the cosine function generating circuit 305, the above DC current is converted into a voltage signal varying in the form of a cosine wave. The driver circuit 302 converts the voltage signal outputted from the sinusoidal function generating circuit 304 into a current signal to be supplied to the first fixed coil 301a. The driver circuit 303 converts the voltage signal outputted from the cosine function generating circuit 305 into a current signal to be supplied to the second fixed coil 301b. Thus, the rpm of the engine is indicated by the coil movement 301. In the conventional measured value indicator system of Fig. 4 constructed as described above, when the response is adjusted in indicating the rpm of the engine by the crossing coil movement, a time constant of the integration circuit 306, when integration is made by varying the values of the resistor and capacitor C of the integration circuit 306, must be varied. Thus, the work of exchanging the circuit components such as the resistor R and capacitor must be carried out. This is very troublesome.

Since the time constant is varied in an analog manner, it was difficult to adjust the time constant with great accuracy.

Further, in many cases, the constants of the circuit components such as the resistor R and capacitor C are standardized. Therefore, it is not easy the circuit components such as the resistor R and capacitor C having the constants outside the standards, thereby making it difficult to adjust the time constant accurately.

The present invention has been accomplished in order to solve the above problem and intends to provide a measurement value indicator system capable of surely suppressing the swing of the needle due to fluctuation of a measured value.

Further, the present invention intends to provide a measured value indicator system capable of shortening the time required for indication test and indication adjustment by making the response easily variable when the measured value is indicated.

Furthermore, the present invention intends to provide a measured value indicator system capable of adjusting the response for the measured value accurately and widely when the measured value is indicated and also easily adjusting the response.

DISCLOSURE OF INVENTION

A measured value indicator system according to the present invention comprises : a measured value inputting terminal to which a measured value of physical quantity is inputted; an arithmetic means for reading the measured value inputted from said measured value inputting terminal to acquire an indication control quantity corresponding to the measured value; a measured value indication unit for making an indication corresponding to said measured value on the basis of the indication control quantity acquired by said arithmetic means; and a measured value reading control means for controlling the permission and inhibition of said measured value inputted from said measured value inputting terminal in accordance with passage of a predetermined time from a starting timing of indication of said measured value.

The measured value indicator system according to the present invention is provided with the measured value reading control means for controlling read of the measured value into the arithmetic means in accordance with time passage from turn- on of an ignition switch.

The measured value indicator system according to the present invention is provided with the measured value reading control means for inhibition read of the measured value into the arithmetic means during the period until a second time elapse after a first time elapses from turn-on of an ignition switch.

The measured value indicator system according to the present invention is provided with a response speed control means for increasing the response in making an indication corresponding to the measured value during a period until a first time elapses from turn-on of the ignition switch and decreasing the response after a second time elapses.

The measured value indicator system according to the present invention is provided with the response speed control means for controlling the response in making an indication corresponding to said measured value by changing a time constant of a signal processing filter for digital processing of the measured value.

A measured value indicator system according to the present invention comprises: a measured value inputting terminal to which a measured value of physical quantity is inputted; a response setting value setting means for setting the indication response in indication test/adjustment and normal indication; a response switching signal inputting terminal for inputting a response switching signal for selecting the response setting value in indication test/adjustment or normal indication from a plurality of response setting values set by said setting means; a response setting value selecting means for selecting the response setting value in said indication test/adjustment or said indication on the basis of the said response switching signal; an arithmetic means for digitally processing a measured value inputted from a measured value inputting terminal on the basis of the response corresponding to the response setting value selected by said response setting value selecting means to acquire an indication control quantity according to said measured value; and a measured value indicating unit for making an indication corresponding to the indication control quantity computed by said arithmetic means.

The measured value indicator system according to the present invention is provided with the arithmetic means for acquiring an indication control quantity corresponding to the measured value newly inputted from said measured value inputting terminal on the basis of a value resulting when a difference between an indication value being indicated by the measured value indicating unit and that of the measured value inputted newly is divided by the response setting value selected by the response setting selecting means.

The measured value indicator system according to the present invention is provided with the response setting value selecting means selects a small response setting value in the indication test/adjustment and a large response setting value in the normal indication.

A measured value indicator system according to the present invention comprises : a memory for storing response setting data for setting the response in making an indication corresponding to a measured value; a response setting data reading means for reading response setting data stored in said memory on the basis of an indication starting signal indicative of the start of an operation indicating a measured value; an indication control quantity arithmetic/outputting means for digitally processing said measured value using a filter having the response corresponding to said response setting data read by said response setting data reading means to compute/output the indication quantity according to the said measured value; and an indication control unit for indicating said measured value according to the indication control quantity computed by said indication control quantity arithmetic/outputting means.

The measured value indicator system according to the present invention uses, as the indication starting signal, a power-on-reset signal generated when an ignition switch is turned on.

The measured value indicator system according to the present invention stores, in the memory, the response setting data corresponding to either of a plurality of stages of "low speed", "intermediate speed" and "high speed" into which the response is classified.

The measured value indicator system according to the present invention applies the measured value to that of an engine rpm of a motor vehicle.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a circuit diagram showing the configuration of a conventional measured value indicator;

Fig. 2 is a block diagram showing the configuration of another conventional measured value indicator;

Fig. 3 is a flowchart showing the operation when test/adjustment of indication is carried out in the conventional measured value indicator system shown in Fig. 2;

Fig. 4 is a block diagram showing the configuration of still another conventional measured value indicator;

Fig. 5 is a block diagram showing the configuration of a measured value indicator system according to the first embodiment of the present invention;

Figs . 6A to 6D are timing charts showing the operation of the measured value indicator system according to the first embodiment of the present invention;

Fig. 7 is a flowchart showing the operation of a data processing circuit of the measured value indicator system according to the first embodiment of the present invention; Fig. 8 is a block diagram showing the configuration of a measured value indicator system according to the second embodiment of the present invention;

Fig. 9 is a flowchart showing the operation when test/adjustment of indication is carried out in the measured value indicator system according to the second embodiment of the present invention;

Fig. 10 is a flowchart showing the operation of the measured value indicator system according to the second embodiment of the present invention.

Fig. 11 is a block diagram showing the configuration of a measured value indicator system according to a third embodiment of the present invention;

Figs. 12A to 12C are diagrams for explaining the operation of an arithmetic means in a digital processing unit of a measured value indicator system according to a third embodiment of the present invention; and

Fig. 13 is a flowchart showing the filtering processing and processing of a function generating circuit by an arithmetic means of a digital processing unit of the measured value indicator system according to the third embodiment according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Now referring to the drawings , a more detailed explanation will be given of the present invention. Fig. 5 is a block diagram showing the configuration of the measured value indicator system according to the first embodiment applied to a fuel meter. In Fig. 5, reference numeral 21 denotes a measured value indicator. Reference numeral 22 denotes an custom IC which may be replaced by a microcomputer. Reference numeral 23 denotes an EEPROM for storing indication characteristic data and others used to process a output signal (measured value) outputted from a fuel meter (not shown) in a digital manner. Reference numeral 24 denotes a filter constant setting unit for storing filter constants Fl an F2 (Fl < F2 ) used to determine a time constant in averaging processing described later. Reference numeral 25 denotes a timer circuit for detecting time passage from when an ignition switch (not shown) is turned on. Reference numeral 26 denotes a RAM having a data area for storing the A-D converted output signal from the fuel meter. Reference numeral 27 denotes a data processing circuit (response control means) which includes an arithmetic means 27a performing averaging processing and PWM computation to compute an indication control amount corresponding to the above fuel meter output signal and a measured value read control means 27b for permitting or inhibiting the fuel meter output signal to be read into the arithmetic means 27. Reference numeral 28 denotes a logical circuit having a filter constant setting unit 24, timer circuit 25, RAM 26, data processing circuit 27, etc. Reference numeral 29 denotes an ignition switch detection circuit for detecting the "on" state and "off" state of the ignition switch on the basis of the output therefrom. Reference numeral 29a denotes an input terminal for inputting the 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 meter output signal. Reference numeral 30a denotes a measured value input terminal for inputting the fuel meter output signal to the A/D converter 30.

Reference numeral 41 denotes a PWM circuit (measured value indicating area) for creating a PWM modulation signal on the basis of the indication control amount corresponding to the fuel meter output signal outputted from the data processing circuit 27. Reference numeral 42 denotes a movement driver (measured value indicating area) for generating a movement driving current on the basis of the PWM modulation signal outputted from the PWM circuit 41. Reference numeral 43 denotes a crossing coil movement (measured value indicating area) supplied with the movement driving current generated from the movement driver 42, which serves to drive a needle (not shown) to indicate the fuel level (remaining fuel amount) corresponding to the fuel meter output signal) . The PWM circuit 41, movement driver 42 and crossing coil movement 43 constitute a measured value indicating unit.

An explanation will be given of the operation of the measured value indicator system 21. Figs. 6A to 6D are timing charts showing the operation of the measured value indicator system 21. As seen from Fig. 6C, while time Tl elapses from when the ignition switch output signal has shifted to "H" level by turn-on of the ignition switch, the measured value indicator system 21 permits the A-D converted fuel meter output signal to be read. This time Tl is preferably e.g. about 1. 7 sec. Until time T3 further elapses after the elapse of time Tl, read of the A-D converted fuel meter output signal is inhibited. In this case, time T2 is a sum of time Tl and time T3. The time T3 to elapse from when the ignition switch output signal has shifted to "H" level is preferably about 7 sec. After the elapse of time T3, read of the fuel meter output signal is permitted. The time constant when the fuel level is indicated until time Tl elapses is set for a smaller value than that after time T3 has elapsed.

Fig. 7 is a flowchart showing the operation of the data processing circuit 27 for realizing the operation shown by the timing chart of Figs. 6A to 6D. In this flowchart, several initial settings are made (step ST1). The timer circuit 25 is reset to start the operation (step ST2 ) . The timer circuit 25 can be realized by hardware or software. It is determined whether or not timing t. indicated by the timer circuit 25 is within a period from when time Tl has elapsed until time T2 elapses (step ST3). When it is determined that the timing t is within the above period, the fuel meter output signal read previously is supplied to the arithmetic means 27a again (step ST4). Thus, the arithmetic means 27a computes the indication angle on the basis of the fuel meter output signal read previously (converts the A-D converted signal into the indication angle data) (step ST5). On the other hand, when it is determined in step ST3 that the timing is not within the above period, a present fuel meter output signal outputted from the A/D converter 30 is read (step ST6). On the basis of this fuel meter output signal, the arithmetic means 27a computes the indication angle on the basis of the fuel meter output signal read previously (converts the A-D converted signal into the indication angle data) (step ST5). Thus, it can be seen that step ST4 and step ST6 corresponds to the measured value read control means 27b.

Next, it is determined whether ont the timing indicated by the timer circuit 25 is in a period after time T2 has elapsed. When it is determined that the timing t. is within this period, the filter constant F2 stored in the filter constant setting unit 24 within the custom IC is read to set the filter constant at F2 (step ST8). On the other hand, when it is determined in step ST7 that the timing t. is not within the period, the filter constant Fl stored in the filter constant setting unit 24 i read to set the filter constant at Fl (step ST10). The filter constant is substituted into an indication angle computing equation in the computing means 27a within the data processing circuit 27 to perform the averaging processing (step ST9 ) . The indication angle computing equation is expressed by

Dn =. Dn-1 + (dn - Dn-1)/N ... (1) where N represents the filter constant Fl (e.g. Fl = 8) selected from the filter constant setting unit 24 or F2 (e.g. F2 = 1024); Dn represents the present indication angle; Dn-l represents the previous indication angle; and dn represents the indication angle corresponding to the fuel sensor signal inputted at the present time. When N is a small value (Fl), the shift amount from the previous indication angle to the present indication angle is large, whereas when N is a large value (F2), the above shift amount is small. In other words, when N is small (Fl), the response is quick, whereas when N is large (F2), the response is slow. Such a processing result is outputted (step ST11) . The processing result is subjected to the computation corresponding to the PWM circuit 41 (step S12) . Further, it is determined whether or not the timing t. indicated by the timer circuit 25 has reached 52. 5 msec. When the timing t. has not reached 52. 5 msec, time is caused to elapse until 52. 5 msec (step ST13). When 52. 5 msec elapses, the processing is returned to step ST2.

As understood from the description hitherto made, the measured value indicator system according to the first embodiment, in step ST4 and step ST6 corresponding to the measured value read control means 27b, does not take any new fuel meter output signal during the period from when time Tl has elapsed until time T3 elapses, but uses the fuel meter output signal taken previously to compute the indication angle corresponding to the fuel meter output signal, thereby outputting the same indication angle as at the previous time. Thus, even when the liquid face level during the above period varies greatly due to fast driving-away or snap-turn of a motor vehicle, the swing of the needle can be surely suppressed.

In the first embodiment described above, until the signal becomes stable (about 500 msec) immediately after the ignition switch output signal has shifted to "H" level by turn- on of the ignition switch, a read inhibiting period while read of the fuel meter output signal is inhibited may be provided, which is succeeded by the processing process described above.

Fig. 8 is a block diagram showing the configuration of the measured value indicator system according to a second embodiment when it is applied to a fuel meter to perform the indication test/adjustment. In Fig. 8, reference numeral 100 denotes a measured value indicator system and numeral 102 denotes an indication adjustment device connected to the measured value indicator system 100. Reference numeral 102 denotes a Vcc power source line connecting terminal for connecting a Vcc power source on the indication adjustment device 101 to a Vcc power source line on the side of the measured value indicator system 100. Reference numeral 103 denotes a ground line connecting terminal for connecting a ground line on the indication adjustment device 101 to a ground line on the measured value indicator system 100. Reference numeral 104 denotes a response switching signal input terminal for inputting a response switching signal for selecting a response setting value in the operation of indication adjustment or normal indication. Reference numeral 105 denotes a measured value input terminal for inputting a fuel sensor signal indicative of the fuel level in the fuel tank. Reference numeral 106 denotes an EEPROM storing indication characteristic data in the operation of normal indication.

Reference numeral 107 denotes a microcomputer which can be replaced by a custom IC . Reference numeral 108 denotes a fuel meter response selecting means (response setting value selecting means) for selecting a response setting value in the operation of indication test/adjustment or normal indication which is set by a response setting value setting means 109 on the basis of the above response switching signal. Reference numeral 109 denotes the response setting value setting means for setting the response setting value defining the indication response of the operation of indication test/adjustment and normal indication. Reference numeral 110 denotes an indication angle computing means (arithmetic means) for processing in a digital manner the fuel sensor signal inputted from the measured value input terminal 105 to compute the indication angle (indication control amount) according to the fuel sensor signal (the fuel sensor signal having the response according to the response setting value selected by the fuel meter response selecting means 108). Reference numeral 111 denotes an output unit for outputting the indication angle computed by the indication angle computing means 110.

Reference numeral 112 denotes a movement driver for supplying the driving current according to the above indicated angle quantity to a crossing coil movement 113. Reference numeral 113 denotes the crossing coil movement composed of X and Y coils arranged to cross each other at an angle of 90° and a movable indication magnet arranged rotatably under the magnetic field of the coils. The movement driver 112 and the crossing coil movement 113 constitute a measured value indicating area for driving/controlling the needle according to the indicated angle quantity computed by the indication angle computing means 110 to indicate the fuel level in the fuel tank.

An explanation will be given of the operation of the indication adjustment device 101 and measured value indicator system 100.

Fig. 9 is a flowchart showing the operation of the indication adjustment device when it tests whether or not the indication is good or not. Fig. 10 is a flowchart showing the operation of the measured value indicator. In carrying out indication test, power is turned on by turn-on of a power switch (step ST1). Next, the response switching signal is shifted to "L" level (step ST2 ) . The fuel sensor signal set at an initial indication test value is outputted to the measured value inputting terminal 105 (step ST3). On the other hand, on the side of the measured value 100, as seen from the flowchart of Fig. 10, it is determined whether or not the response switching signal is at "L" level (step ST11). When it is determined that the response switching signal is at "L" level, the response setting value N = 8 defining the response of indication in the indication test/adjustment, which has been set by the response setting value setting means 109, is selected by the fuel meter response selecting means 108 (step S12). When the response switching signal is at "H" level, the response setting value N = 1024 is selected (step ST13). Using the selected response setting value, an indication angle is computed by the indication angle computing means 110 (step ST14). The indication angle is computed by

Dn = Dn-1 + (dn - Dn-1)/N ... (2) where N represents the response setting value selected by the fuel meter response selecting means 108 (N of a large value means slow response whereas N of a small value means quick response); Dn represents the present indication angle; Dn-1 represents the previous indication angle; and dn represents the indication angle corresponding to the fuel sensor signal inputted at the present time. The indication angle thus computed is outputted to the movement driver 112 through the output unit 111 from the indication angle computing means 110 (step ST15) . Therefore, since the response of indication in the normal indication operation is in a slow state whereas that in the indication test/adjustment is in a quick state, in quick response to the fuel sensor signal supplied from the indication adjustment device when the indication test/adjustment is performed, the needle of the crossing coil 113 makes the indication. Thus, in the subsequent step ST4 , after five or more sec has elapsed, the indication adjustment device determines whether the indication value is good or not (step ST5). If the indication value is not good, the indication adjustment is carried out (step ST6 ) . If the indication value is good, the fuel sensor signal set at a next indication test value is outputted to the measured value inputting terminal 105 (step ST8). Until the indication test/adjustment for the fuel sensor signal set at a final indication test value is completed, the processing from step ST4 to step ST7 is repeated. When the indication test is completed, the power is turned off (step ST9).

In accordance with the measured value indicator system according to this embodiment, in the indication test/adjustment, the response of indication for a change in the fuel sensor signal becomes quick so that the time required for the indication test/adjustment can be shortened. In the normal indicating operation, the response for a change in the fuel sensor signal becomes slow so that the swing of the needle for the variation in the liquid face can be suppressed. Incidentally, in this embodiment, although the setting values of the response in both indication test and indication adjustment have been set at small values, either one can be selected as required. Different setting values of response may be also adopted as required.

Fig. 11 is a block diagram of the configuration of the measured value indicator system applied to a tachometer for indicating the rpm of an engine. In Fig. 11, reference numeral 301 denotes a crossing coil movement (indication control area) composed of a first fixed coil 301a and a second fixed coil 301b which serves as a needle driving mechanism. Reference numeral 302 denotes a driver circuit (indication control unit) for supplying to the first fixed coil 301a a driving current corresponding to a voltage signal having a sinusoidal waveform generated in a function generating circuit 311. Reference numeral 303 denotes a driver circuit (indication control unit) for supplying to the second fixed coil 301b a driving current corresponding to a voltage signal having a cosine waveform generated in the function generating circuit 311. Reference numeral 311 denotes a function generating circuit for generating voltage signals having a sinusoidal and a cosine waveform on the basis of the output from an arithmetic means 303b of a digital processing unit (indication control quantity outputting means). Reference numeral 312 denotes an ROM storing function generating data for creating the voltage signals having the sinusoidal and cosine waveforms to be generated by the function generating circuit 311. Reference numeral 313 denotes a digital processing unit. The digital processing unit 313 includes a response setting data reading means 303a for reading the response setting data stored in an EEPROM (memory) 314 on the basis of a power-on reset signal (indication starting signal) outputted when an ignition switch (not shown) is turned on and an arithmetic means 303b for filtering, by digital computation, the measured value inputted as a pulse signal whose period varies according to the rpm of the engine using a filter corresponding to the response setting data read by the response setting data reading means 303a. Reference numeral 314 denotes an EEPROM storing response setting data corresponding to either one of three speeds "low speed", "intermediate speed" and "high speed" into which the response speed is classified. Reference numeral 315 denotes a waveform shaping circuit for waveform-shaping the pulse signal supplied to the pulse signal inputting terminal 316.

EEPROM 314 previously stores digital filter constants M, N and L for constituting a filter as the response setting data. The filtering includes primary filtering and secondary filtering. The filter constant M is used in the computation of the primary filtering whereas the filter constants N and L are used in the computation of the secondary filtering.

Figs. 12A to 12C are explanation views showing the operation of the arithmetic means 303b of the digital processing unit 313. Fig. 12A shows a digital computation process in which the pulse signal outputted from the waveform shaping circuit 315 is subjected to filtering using the filter having the response corresponding to the response setting data read from the EEPROM 314 by the response setting data reading means 303a. In this figure, numeral 321 denotes the primary filtering step and numeral 323 denotes the secondary filtering step.

An explanation will be given of the operation of the measured value indicator system according to this embodiment .

When power is turned on by turn-on of an ignition switch, the filter constants M, N and L are read from the EEPROM 314 on the basis of the power-on reset signal. Thus, the pulse signal supplied to the pulse signal inputting terminal 316 is waveform-shaped by the waveform shaping circuit 315. The pulse signal thus waveform-shaped is subjected to digital processing, for each period thereof, using the filter constants M, N and L by the arithmetic means 303b of the digital processing unit 313. In this digital processing, the pulse signal is digitally integrated by the primary filtering process 321 shown in Fig. 12A at the repetition rate of 6. 25 μsec during one period T of the pulse signal according to the following equation (3), thus providing a primary integrated value Dn for the pulse signal. Dn = Dn-l + 1/M (dn - Dn-l) ... (3) where Dn-l represents output data in the previous primary filtering step 321, and as seen from Fig. 12B, dn is set at "1" during the period τ while the pulse signal is at "H" level and is set at "0" during the remaining period.

In the secondary filtering step 322 shown in Fig. 12A, an average value of N number of primary integrated values Dn computed by the primary filtering process 321 is computed according to the following equation (4). The number N of the primary integrated values Dn is set at '512' for "low speed", '256' for "intermediate speed" and '126' for "high speed" in three stages of the response as shown in Fig. 12C.

N

DN = 1/N Σ Dn ... (4) n-l

In the secondary filtering step 323, the pulse signal is digitally integrated at the repetition rate of 6. 25 μsec x N during one period T of the pulse signal according to the following equation (5), thus providing a secondary integrated value Dn' for the pulse signal.

D'n = D'n-l + 1/L (Dn - D'n-l) ... (5) where D'n-l represents output data in the previous secondary filtering step 323 and L represents the filter constant that is set at "32". In this way, the pulse signal inputted from the pulse signal inputting terminal 316 is subjected to the digital filtering. The result of filtering is supplied from the digital processing unit 313 to the function generating circuit 311.

Fig. 13 is a flowchart showing the filtering by the arithmetic means 303b of the digital processing unit 313 and the processing in the function generating circuit 311 for creating a driving current of the crossing coil movement 301. The process from step STl to step ST7 and from step ST9 to step ST10 corresponds to the digital processing operation by the arithmetic means 3b in the digital processing unit 313, and the process of step ST8 corresponds to the processing by the function generating circuit 311.

Accordingly, the driving currents corresponding to the voltage signals having sinusoidal and cosine waveforms generated by the function generating circuit 311 in accordance with the processing result by the arithmetic means 303b of the digital processing unit 313 are supplied from the driver circuits 302 and 303 to the first fixed coil 301a and second fixed coil 301b of the crossing coil movement 301, thereby indicating the rpm of an engine. In this case, the response in the filtering having a wide range filtering characteristic using the filter constants M, N and L can be changed into three stages of "high speed", "intermediate speed" and "low speed" by changing the filter constant N, thus enabling the response in indication of the engine rpm to be changed into the above three stages . The response can be made variable by changing the filter constant M or L. Further, by changing two of more of the filer constants M, N and L, the response can be made variable, and in this case, it can be finely adjusted. In this embodiment, although

N was set at three stages of "high speed", "intermediate speed" and "low speed", it may be set at three or more stages. INDUSTRIAL APPLICABILITY

As understood from the description hitherto made, since a measured value indicator system according to the present invention is constructed to comprise a measured value inputting terminal to which a measured value of physical quantity is inputted, an arithmetic means for reading the measured value inputted from said measured value inputting terminal to acquire an indication control quantity corresponding to the measured value, a measured value indication unit for making an indication corresponding to said measured value on the basis of the indication control quantity acquired by said arithmetic means and a measured value reading control means for controlling the permission and inhibition of said measured value inputted from said measured value inputting terminal in accordance with passage of a predetermined time from a starting timing of indication of said measured value, the swing of an indication needle due to a change in the measured value generated when the predetermined time elapses from the starting timing can be surely suppressed. For this reason, the measured value indicator system according to the present invention is suitable to a fuel meter for indicating a fuel level which is mounted on a motor vehicle.

Since the measured value indicator system according to the present invention comprises a measured value reading control means for controlling read of the measured value into the arithmetic means in accordance with time passage from turn- on of an ignition switch, the swing of an indication needle due to a change in the measured value generated when a predetermined time elapses from turn-on of the ignition switch can be surely suppressed.

Since the measured value indicator system according to the present invention comprises a measured value reading control means for inhibiting read of the measured value into the arithmetic means during the period until a second time elapse after a first time elapses from turn-on of an ignition switch, the swing of an indication needle due to a change in the measured value generated during said period can be surely suppressed.

Since the measured value indicator system according to the present invention comprises a response speed control means for increasing the response in making an indication corresponding to the measured value during a period until a first time elapses from turn-on of the ignition switch and decreasing the response after a second time elapses, the indication corresponding to the measured value is made quickly during the period until the first time elapses so that the indication when the ignition switch is turned on exhibits a real value corresponding to the measured value .

Since the measured value indicator system according to the present invention comprises a response speed control means for controlling the response in making an indication corresponding to said measured value by changing a time constant of a signal processing filter for digital processing of the measured value, the response can be controlled by the digital processing.

Further, since the measured value indicator system according to the present invention is constructed to comprise a response switching signal inputting terminal for inputting a response switching signal for selecting a response setting value in indication test/adjustment or normal indication from a plurality of response setting values set by a setting means, a response setting value selecting means for selecting the response setting value in said indication test/adjustment or said indication on the basis of the said response switching signal, an arithmetic means for digitally processing a measured value inputted from a measured value inputting terminal on the basis of the response corresponding to the response setting value selected by said response setting value selecting means to acquire an indication control quantity according to said measured value, and a measured value indicating unit for making an indication corresponding to the indication control quantity computed by said arithmetic means, said response setting value selecting means can select the response in said indication test/adjustment on the basis of the response switching signal so that it is higher than that in the normal indication, thereby shortening the time required for indication test and adjustment. For this reason, the measured value indicator system according to the present invention is suitable to a fuel meter for a motor vehicle.

The measured value indicator system according to the present invention, on the basis of a value resulting when a difference between an indication value being indicated by the measured value indicating unit and that of the measured value inputted newly is divided by the response setting value selected by the response setting selecting means, acquires the indication control amount corresponding to the measured value inputted from said measured value inputting terminal. Thus, the changing rate of the indication control quantity corresponding to the measured value can be made variable so that the response in indicating the measured value can be adjusted on the basis of said response setting value.

Since the measured value indicator system is provided with a response setting value selecting means for selecting a small response setting value in the indication test/adjustment and a large response setting value in the normal indication, the response in the indication test/adjustment can be made "high speed" whereas that in the normal indication can be made "low speed", with the effects that a period of time necessary for checking the results of the indication and for adjusting the indication can be reduced.

The measured value indicator system is constructed to comprise a response setting data reading means for reading response setting data stored in a memory on the basis of an indication starting signal indicative of the start of an operation indicating a measured value, an indication control quantity arithmetic/outputting means for digitally processing said measured value using a wide range filtering characteristic having the response corresponding to said response setting data read by said response setting data reading means to compute/output the indication quantity according to the said measured value, and an indication control unit for indicating said measured value according to the indication control quantity computed by said indication control quantity arithmetic/outputting means. Thus, by changing the response setting data stored in said memory, the response in indicating the measured value can be adjusted easily, widely and accurately. For this reason, the measured value indicator system according to the present invention is suitable to a tachometer for indicating the engine rpm of a motor vehicle.

The measured value indicator system according to the present invention is constructed to comprise a response setting data reading means for reading response setting data stored in a memory on the basis of a power-on-resetting signal generated when an ignition switch is turned on, an arithmetic/outputting means for digitally processing said measured value using a wide range filtering characteristic having the response corresponding to said response setting data read by said response setting data reading means to compute/output the indication control quantity according to the said measured value, and an indication control unit for indicating said measured value according to the indication control quantity computed by said indication control quantity arithmetic/outputting means. Thus, by changing the response setting data stored in said memory, the response in indicating the measured value simultaneously with power-on-resetting can be adjusted easily, widely and accurately.

The measured value indicator system is constructed to comprise a response setting data reading means for reading either of response setting data stored in a memory and classified into a plurality of stages of "low speed", "intermediate speed" and "high speed" on the basis of an indication starting signal indicative of the start of an operation indicating a measured value, an indication control quantity arithmetic/outputting means for digitally processing said measured value using a filter having the response corresponding to said response setting data read by said response setting data reading means to compute/output the indication quantity according to the said measured value, and an indication control unit for indicating said measured value according to the indication control quantity computed by said indication control quantity arithmetic/outputting means. Thus, by changing the response setting data stored in said memory, the response in indicating the measured value can be easily, widely and accurately adjusted into either of a plurality of stages inclusive of the "low speed", "intermediate speed" and "high speed" .

Since the measured value indicator system according to the present invention is applied to the measured value for the engine rpm of a motor vehicle, the response in indicating the measured value of the engine rpm of the motor vehicle can be easily, widely and accurately.

Claims

1. A measured value indicator system comprising: a measured value inputting terminal to which a measured value of physical quantity is inputted; an arithmetic means for reading the measured value inputted from said measured value inputting terminal to acquire an indication control quantity corresponding to the measured value; a measured value indication unit for making an indication corresponding to said measured value on the basis of the indication control quantity acquired by said arithmetic means ; and a measured value reading control means for controlling the permission and inhibition of said measured value inputted from said measured value inputting terminal in accordance with passage of a predetermined time from a starting timing of indication of said measured value.
2. A measured value indicator system as claimed in claim
1, wherein said measured value reading control means controls read of the measured value into the arithmetic means in accordance with time passage from turn-on of an ignition switch.
3. A measured value indicator system as claimed in claim
2, wherein said measured value reading control means inhibits read of the measured value into the arithmetic means during the period until a second time elapse after a first time elapses from turn-on of an ignition switch.
4. A measured value indicator system as claimed in claim
3, further comprising: a response speed control means for increasing the response in making an indication corresponding to the measured value during a period until a first time elapses from turn-on of the ignition switch and decreasing the response after a second time elapses .
5. A measured value indicator system as claimed in claim
4, wherein said response speed control means controls the response in making an indication corresponding to said measured value by changing a time constant of a signal processing filter for digital processing of the measured value.
6. A measured value indicator system comprising: a measured value inputting terminal to which a measured value of physical quantity is inputted; a response setting value setting means for setting the indication response in indication test/adjustment and normal indication; a response switching signal inputting terminal for inputting a response switching signal for selecting the response setting value in indication test/adjustment or normal indication from a plurality of response setting values set by said setting means; a response setting value selecting means for selecting the response setting value in said indication test/adjustment or said indication on the basis of the said response switching signal; an arithmetic means for digitally processing a measured value inputted from a measured value inputting terminal on the basis of the response corresponding to the response setting value selected by said response setting value selecting means to acquire an indication control quantity according to said measured value; and a measured value indicating unit for making an indication corresponding to the indication control quantity computed by said arithmetic means.
7. A measured value indicator system as claimed in claim 6, wherein said arithmetic means acquires an indication control quantity corresponding to the measured value newly inputted from said measured value inputting terminal on the basis of a value resulting when a difference between an indication value being indicated by the measured value indicating unit and that of the measured value inputted newly is divided by the response setting value selected by the response setting selecting means.
8. A measured value indicator system as claimed in claim 7, wherein said response setting value selecting means selects a small response setting value in the indication test/adjustment and a large response setting value in the normal indication.
9. A measured value indicator system comprising: a memory for storing response setting data for setting the response in making an indication corresponding to a measured value; a response setting data reading means for reading response setting data stored in said memory on the basis of an indication starting signal indicative of the start of an operation indicating a measured value; an indication control quantity arithmetic/outputting means for digitally processing said measured value using a filter having the response corresponding to said response setting data read by said response setting data reading means to compute/output the indication control quantity according to the said measured value; and an indication control unit for indicating said measured value according to the indication control quantity computed by said indication control quantity arithmetic/outputting means.
10. A measured value indicator system as claimed in claim
9, wherein said indication starting signal is a power-on-reset signal generated when an ignition switch is turned on.
11. A measured value indicator system as claimed in claim
10, wherein said response setting data corresponds to either of a plurality of stages of "low speed", "intermediate speed" and "high speed" into which the response is classified.
12. A measured value indicator system as claimed in claim
11, wherein said measured value is that of an engine rpm of a motor vehicle.
PCT/JP1997/002604 1996-07-29 1997-07-28 Measured value indicator system WO1998004888A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP8/199387 1996-07-29
JP19938796A JP3492474B2 (en) 1996-07-29 1996-07-29 Measurement value display
JP20226996A JP3583231B2 (en) 1996-07-31 1996-07-31 Measurement value display
JP8/202269 1996-07-31
JP8/203608 1996-08-01
JP20360896A JPH1047991A (en) 1996-08-01 1996-08-01 Measured value displaying device

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USRE40279E1 (en) 1997-06-26 2008-04-29 Sherwood Services Ag Method and system for neural tissue modification
USRE41045E1 (en) 1996-06-27 2009-12-15 Covidien Ag Method and apparatus for altering neural tissue function

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EP0446417A1 (en) * 1990-03-14 1991-09-18 VDO Adolf Schindling AG Liquid quantity measuring system
WO1993013392A1 (en) * 1991-12-23 1993-07-08 Ford Motor Company Limited Digital smoothing circuit for electronic level indicators
US5357196A (en) * 1991-08-06 1994-10-18 Jeco Company Limited Circuit for converting a frequency of an input signal so a signal having a digital value corresponding to the frequency
US5379637A (en) * 1993-10-12 1995-01-10 General Motors Corporation Natural gas vehicle fuel gauge system
WO1995021368A1 (en) * 1994-02-03 1995-08-10 Marwal Systems Filtering device particularly for a fuel gauge of a motor vehicle
FR2737298A1 (en) * 1995-07-27 1997-01-31 Marwal Systems Sa Tank and fuel gauge for vehicle - using transductor to detect fuel level, and memory to relate fuel levels to fuel volume

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Publication number Priority date Publication date Assignee Title
GB2122750A (en) * 1981-12-28 1984-01-18 Nissan Motor Fuel gauge for automobile
EP0446417A1 (en) * 1990-03-14 1991-09-18 VDO Adolf Schindling AG Liquid quantity measuring system
US5357196A (en) * 1991-08-06 1994-10-18 Jeco Company Limited Circuit for converting a frequency of an input signal so a signal having a digital value corresponding to the frequency
WO1993013392A1 (en) * 1991-12-23 1993-07-08 Ford Motor Company Limited Digital smoothing circuit for electronic level indicators
US5379637A (en) * 1993-10-12 1995-01-10 General Motors Corporation Natural gas vehicle fuel gauge system
WO1995021368A1 (en) * 1994-02-03 1995-08-10 Marwal Systems Filtering device particularly for a fuel gauge of a motor vehicle
FR2737298A1 (en) * 1995-07-27 1997-01-31 Marwal Systems Sa Tank and fuel gauge for vehicle - using transductor to detect fuel level, and memory to relate fuel levels to fuel volume

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE41045E1 (en) 1996-06-27 2009-12-15 Covidien Ag Method and apparatus for altering neural tissue function
USRE40279E1 (en) 1997-06-26 2008-04-29 Sherwood Services Ag Method and system for neural tissue modification

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