JPH05180872A - Indicating instrument - Google Patents

Abstract

PURPOSE:To facilitate the quick following of a needle to a change in an object to be measured and to dissolve a needle shake resulted from quick responsibility by executing a smooth processing having a long (or short) response time in the case of a small (or large) change in the output of a converting section when the response characteristic of a smoothing section is changed over. CONSTITUTION:A subtracting circuit 312 computes a difference between the output of a memory circuit 311 which stores the output quantity of a converting section to send out it and the then output of the converting section. A comparison circuit 313 compares the result of subtraction with a predetermined value. When a change in the output Y of the converting section is small, a L level is sent out from the comparison circuit 313, and a small N value is determined and processed through a sampling signal F having a long cycle. When the change in the output Y of the converting section is large, an H level is sent out from the comparison circuit 313, and the large N value is determined and processed through the sampling signal F having a short cycle. The above processed output is fed to a drive-processing section as the output of a smoothing section, and then turns into a needle driving output through a display section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrument for indicating a pointer, such as a cross-coil instrument, and more particularly to an instrument having a digital smoothing portion.

[0002]

2. Description of the Related Art A general indicating instrument appropriately processes signals from various sensors installed on an object to be measured and converts them into an appropriate pointer drive signal to indicate the state of the object to be measured by a pointer. In such an indicating instrument, the sensor signal is once digitized for signal (information) processing from various sensors, predetermined processing is performed by digital signal processing, and then analogized again to drive a pointer. There is.

More specifically, when the number of revolutions of a vehicle engine is displayed using a cross-coil type indicator, the sensor outputs a pulse signal having a frequency proportional to the number of revolutions of the engine. The V value is converted and the voltage signal is converted into a digital signal (digital numerical value), or the state of the non-measurement target is output as a digital signal by counting the pulse signals or measuring the period (converter output). The calculated pointer drive amount corresponding to the above is calculated by the CPU, or a predetermined pointer drive amount is output as a digital signal by using a ROM in which corresponding numerical values are stored in advance. Is used to drive the pointer by analogizing.

Further, in the above-mentioned indicating instrument, in order to prevent the pointer reversal preventing means of the cross coil type instrument and the stepwise display of the indicating instruction due to the coarsening of the sensor function due to the cost reduction of the sensor, the indicating instrument is indicated. Is a smoothing unit (digital filter) that smoothes the output (digital signal) of the converter.
There is known an instrument provided with the Japanese Patent Laid-Open No. 2-5106.
No. 5).

The smoothing portion of this indicator has a long response time so that, for example, instability of the engine speed when the engine is running at low speed does not give an instruction to the engine, and the instruction follows quickly at high engine speed. The response characteristics are switched based on only the size of the output of the conversion unit, such as shortening the response time.

[0006]

SUMMARY OF THE INVENTION In order to distinguish the switching of the response characteristic of the smoothing portion of the above-mentioned conventional indicating instrument into, for example, low rotation in the engine idling range and high rotation when the vehicle is running, the output of the conversion portion is changed. If only high or low with respect to the reference value (input boundary) is used as a reference, for example, when the accelerator is strongly depressed, if the response is changed from a slow response state, quick tracking of the instrument pointer corresponding to the engine speed is hindered. Further, when the engine has a high responsiveness and at high engine speed, the measurement error in the conversion unit appears as a needle shake.
Therefore, the present invention proposes an improvement in the method of switching the response characteristic of the smoothing portion.

[0007]

SUMMARY OF THE INVENTION An indicating instrument according to the present invention comprises a converter for digitizing an input signal from an object to be measured and a drive for outputting a predetermined pointer indicating signal corresponding to the digital signal from the converter. A smoothing unit that includes a processing unit and a display unit that operates a pointer by receiving a drive output, and that includes a smoothing unit that performs a digital smoothing process of the conversion unit output signal is provided between the conversion unit and the drive processing unit. Is provided with a plurality of processing functions having different smooth response characteristics, and is provided with a means for determining the change amount of the conversion unit output signal and switching the smooth response characteristics according to the change amount. is there.

[0008]

The principle of switching the response characteristic of the smoothing section is based on the change amount of the output of the converting section. That is, when the change in the conversion unit output is small, smoothing processing with a long response time is performed, and when the change amount in the conversion unit output is large, smoothing processing with a short response time is performed.

[0009]

EXAMPLES Next, examples of the present invention will be described. The indicating instrument of the present invention is, for example, a cross-coil type instrument,
The overall configuration of the instrument is composed of a conversion unit 1, an AND circuit 2, a smoothing unit 3, a drive processing unit 4 and a display unit 5. The conversion unit 1 is composed of a waveform shaping circuit 11 and a frequency counting circuit 12, and when a pulse X generated according to the operation of an object to be measured is inputted, the pulse signal is shaped and the number of input pulses is given every predetermined gate time. The digital signal corresponding to the count number (for example, 8-bit digital number)
Is output (converter output Y).

The AND circuit 2 inputs a conversion unit input and a zero-reversal inverse signal, and normally outputs the conversion unit output X to the smoothing unit 3 as it is, but when a zero-reduction signal is input, it goes to the smoothing unit 3. The output of is forcibly set to "zero numerical value" and the pointer is zeroed. The smoothing unit 3 uses the digital filter 31.
2, the digital filter 31 is composed of an adder 311, a delay device 312, and a multiplier 313 as shown in FIG. 2. The input AND circuit output (converter output Y) is converted into a sampling signal. Generation circuit 3
The sampling signal F from 2 is smoothed by the response characteristic determined by the frequency, and the smoothed signal Z is output.

The sampling signal generation circuit 32 is a memory circuit 321 for the previous input amount for calculating the change amount of the output Y of the conversion unit, a subtraction circuit 322 for calculating the difference between the previous input amount and the current input amount, and the subtraction result. Comparing circuit 323 that compares a predetermined value with a predetermined value, and an N value setting circuit 32 that determines the cycle of the sampling signal F based on the comparison result.
4, an oscillator circuit 325 that outputs a reference pulse f, and an f / N count circuit 326 that outputs a sampling signal F based on the reference pulse f and the N value.

The drive processing section 4 comprises a ROM section 41, a D-A conversion section 42 and a drive output section 43. The ROM section 41 stores the digital output corresponding to the output signal Z of the smoothing section 3 and stores it in the smoothing section. When it receives an input signal from 3, it makes a digital output that has been memorized, and the next D-A conversion unit 42 performs D-A conversion of the digital signal and sends it to the drive output unit 43, and the drive output unit 43 drives the pointer. The output of the driving current is. The display unit 4 is composed of a pointer, a display plate, a drive coil, etc., and gives a pointer instruction corresponding to the drive unit input signal.

Next, the operation of the above embodiment will be described.
When the measured object is, for example, the engine speed, when the frequency signal X proportional to the engine speed is input to the converter, the converter 1
Then, the number of input signals of the signal X for each predetermined gate time is counted and converted into an 8-bit digital signal. The converted output numerical value (digital signal) Y that has been converted is input to the smoothing unit 3 via the AND circuit 2, subjected to predetermined smoothing processing, and output to the drive processing unit 4 as a 10-bit smoothing unit output Z.
When input to the drive processing unit 4, the ROM unit 41 calculates the drive output amount (analog amount) of the display unit 4 corresponding to the input, and makes a predetermined pointer drive output.

The present invention is particularly characterized by the above-mentioned smoothing characteristic switching means, which is a conversion unit output Y.
When the change in is small, the smoothing process with a long response time is performed, and when the change amount of the conversion unit output Y is large, the smoothing process with a short response time is performed.

That is, the subtraction circuit 322 calculates the difference between the output of the memory circuit 321 that stores and outputs the immediately preceding conversion unit output amount and the conversion unit output at that time, and the comparison circuit 323 determines in advance the subtraction result. The comparison value is compared with a predetermined value, and if it is larger, the comparison circuit 323 outputs "H level", and if the change amount is smaller, "L level" is output, and the N value setting circuit 324.
Then, the N value is uniquely determined based on the above “H, L level”, and the sampling signal F having a cycle obtained by dividing the reference pulse f into 1 / N is output from the f / N count circuit 326, and the sampling signal The processing timing of the digital filter 31 is determined by F.

Therefore, when the change amount of the conversion unit output Y is small, the comparison circuit 323 outputs "L level", a small N value is determined, and the sampling signal F having a long cycle is processed. When the amount of change in the output Y of the conversion unit is large, "H level" is output from the comparison circuit 323, a large N value is determined, and the sampling signal F having a short cycle is processed.

The present invention is not limited to the above-mentioned embodiment, and in particular, in the above-mentioned embodiment, for simplification of the description, the subtraction and the comparison judgment for calculating the output change of the conversion unit are compared with the input of the conversion unit immediately before. However, it is not always necessary to make a single comparison, and for example, an average value of several inputs may be obtained and used as a comparison reference bet. Further, a plurality of N value setting circuits may be provided to finely switch the response characteristics. Further, the present invention, if the means for switching the response characteristic of the digital unit smoothing unit in the instrument is determined based on the amount of change in the output of the converting unit, the specific smoothing processing unit of the smoothing unit, the response characteristic switching circuit, etc. Can be arbitrarily set, and of course, the specific configurations of the conversion unit, the drive output unit, the display unit, and the like can also be arbitrarily set.

[0018]

As described above, the present invention is an indicator instrument having a smoothing unit for digitally smoothing a conversion unit output signal which digitizes and outputs an input signal from an object to be measured. It has a function to switch the smooth response characteristic by discriminating the amount of change in the signal, which enables quick tracking of the pointer movement to the change of the measured object, and there is also the problem of finger shake that occurs due to quick response. It has been resolved.

[Brief description of drawings]

FIG. 1 is a simple circuit block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a digital filter of a smoothing unit of the embodiment.

FIG. 3 is a block diagram showing a configuration of a sampling signal generating circuit of the smoothing unit.

[Explanation of symbols]

 1 conversion unit 2 AND circuit 3 smoothing unit 31 digital filter 32 sampling signal generation circuit 4 drive processing unit 5 display unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Otani 190-1 Fukuda-cho, Nagaoka-shi, Niigata Nihon Seiki Co., Ltd. R & D Center

Claims (1)

[Claims] 1. A conversion unit that counts and digitizes an input pulse signal from an object to be measured, a drive processing unit that outputs a predetermined pointer indicating signal corresponding to the digital signal from the conversion unit, and a drive output. A smoothing section for digitally smoothing the output signal of the converting section is provided between the converting section and the drive processing section, and the smoothing section has a plurality of different smoothing response characteristics. An indicating instrument characterized in that it has a processing function of (1) and determines a change amount of the output signal of the conversion unit and switches the smoothing response characteristic according to the change amount.