JPS63210778A - Driving device for cross coil type instrument - Google Patents

Abstract

PURPOSE:To drive a cross coil type instrument with display information obtained in the form of digital data by processing a sensor signal yet by providing a data input terminal, a duty determination data generating means, a variable duty rectangular wave generating means, and a driver means. CONSTITUTION:Information displayed by the deflection angle of the pointer of the cross coil type instrument A is inputted to a data input terminal IN in the form of digital data. The duty determination data generating means B inputs the inputted digital data and divides pointer deflection angles corresponding to respective digital data into plural parts with digital data inputted before and after said input digital data to generate duty determination data for determining the duty of a necessary rectangular wave for generating a point deflection angle. The variable duty rectangular wave generating means C generates the rectangular wave with the duty corresponding to the duty determination data generated by the means B. Then the driver means D supplies a current to one cross coil with one level of the rectangular wave generated by the means C and to the other with the other level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive device for a cross-coil type meter.

[Prior art and problems to be solved by the invention] Conventionally,
The information to be displayed on this type of meter is input in the form of an analog voltage value generated by, for example, a change in resistance value in response to a change in liquid volume, and the pointer changes as the analog voltage value changes. The deflection angle is designed to change.

The deflection angle of the pointer is determined by the direction of the composite vector of the magnetic field generated by each coil by passing current through a pair of coils arranged in an intersecting manner.In order to change the direction of the composite peltle, The ratio of current flowing through each coil is changed directly using analog amounts from sensors, etc.

Incidentally, recently, in various types of vehicles, various signal data generated within the vehicle are collectively collected and processed as digital data in the on-board computer, and in this regard, most of the data Most of the time, the display is digital.

However, even in vehicles where the digital processing of signal data has progressed in this way, many users desire that the display be performed by an analog meter with a pointer. In such cases, it is possible to deal with this by separately incorporating a circuit system that generates and processes analog signal data for display without using digital data for display. In addition to wasting circuitry, this has caused many problems, such as the complexity of the circuitry and increased cost.

SUMMARY OF THE INVENTION In view of the problems of the conventional devices described above, the present invention provides a driving device for a cross-coil type meter that can drive the cross-coil type meter using display information in which sensor signals have already been processed and become digital data. This is what I am trying to do.

[Means for solving problems]

In order to solve the above-mentioned problems, the drive device for a cross-coil type meter according to the present invention, as shown in the basic configuration diagram of FIG. A pointer that captures a data input terminal IN that is input in the form of a shape, and digital data that is input to the data input terminal IN, and divides the pointer deflection angle corresponding to each digital data into a plurality of parts by the digital data that are captured one after another. A duty determining data generating means B that generates duty determining data for determining the duty of a rectangular wave necessary to generate a deflection angle, and a duty rectangle according to the duty determining data generated by the duty determining data generating means B. A variable duty rectangular wave generating means C that generates a wave, and a driver that causes current to flow through one of the cross coils at one level of the rectangular wave generated by the variable duty rectangular wave generating means C, and through the other side of the cross coil at the other level. Equipped with means and means.

[For production]

One of the cross coils to the cross coil type meter is energized at one level of the rectangular wave generated by the variable duty rectangular wave generating means C, and the other is energized at the other level of the rectangular wave, and the rectangular wave The duty is determined by a plurality of duty determination data obtained from successive digital data to be displayed at the pointer deflection angle of instrument A, so when digital data is input, the display corresponding to the data is The variable duty rectangular wave generating means C generates a rectangular wave having a duty that sequentially increases or decreases necessary to perform the above, and a predetermined display is displayed while changing smoothly.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Fig. 2 is a circuit block diagram of a drive device for a cross-coil type meter according to the present invention, where ■ is a microcomputer that receives digital data containing information such as liquid volume, temperature, voltage, etc. from a data input terminal IN. Central processing unit (C
PU), which processes digital data according to a predetermined program and outputs data that determines the duty of the rectangular wave.

Reference numeral 2 denotes a variable duty rectangular wave generation circuit that generates a rectangular wave with a duty according to the digital data based on duty determination data output by the CPU 1 after processing the digital data. 3a and 3b are cross coils disposed orthogonally to each other constituting the cross coil type instrument 3, and each cross coil 3a.

One end of 3b is connected to a power source. Reference numerals 4a and 4b are drivers that receive the rectangular wave generated by the variable duty rectangular wave generation circuit 2 and send current to the cross coils 3a and 3b, respectively.

The output of 4b is connected to the other ends of cross coils 3a and 3b, respectively. The driver 4a is an amplifier 4a that non-inverts and amplifies the rectangular wave from the variable duty rectangular wave generation circuit 2.
, and a switching transistor 4a that is turned on when the output of the amplifier 4a+ is at the H level, and allows current to flow through the cross coil 3a while the output of the variable duty rectangular wave generating circuit 2 is at the H level. On the other hand, the driver 4b includes an amplifier 4b+ that inverts and amplifies the rectangular wave from the variable duty rectangular wave generation circuit 2, and a switching transistor 4b! that is turned on when the output of the amplifier 4b+ is at H level. A current is caused to flow through the cross coil 3b while the output of the variable duty rectangular wave generating circuit 2 is at the L level.

When the CPU 1 has an 8-bit configuration, digital data is handled in units of 8 bits, so the variable duty rectangular wave generating circuit 2 shown in FIG. 3, for example, is used.

In FIG. 3, 2a is an 8-bit shift register into which 8-bit duty determination data is input serially from CUPl, 2b is an 8-bit comparison counter into which a count-up clock is input from a clock generator (not shown), and 2C is an 8-bit comparison counter into which a count-up clock is input from a clock generator (not shown). The contents of the shift register 2a and comparison counter 2b are compared, and when the shift register 2a is larger, the output is set to L level, and when the comparison counter 2b is larger, the output is set to H level, and the output is output. A rectangular wave with a duty according to the duty determination data is output.

Now, if data 03H (hexadecimal) is set in the shift register 2a and the comparison counter 2b is reset, the magnitude comparator 2c compares the contents of both, and since the shift register 2a is larger, the output is at L level. Output.

After that, when the counter up pulse is input to the comparison counter 2b and its contents are amplified by 1, the value of the comparison counter 2b becomes 1, but the shift register 2b still
Since the content of a is larger, the output of the magnitude comparator 2C is at L level. However, if the comparison counter 2b continues to count and amplify sequentially, the content of the comparison counter 2b becomes larger than the content of the shift register 2a, and at that point the output of the magnitude comparator 2C is inverted and becomes H level.

Since the comparison counter 2b continues to count up after that, the output of the magnitude comparator 2C continues to take the H level, but the content of the comparison comparator 2b remains FFH.
When it rolls over from (hexadecimal) to OOH, the content of the comparison counter becomes smaller than that of the shift register 2a, so the output of the magnitude comparator 2C is inverted again and becomes L level. By repeating the above operations, 3/2
This means that a rectangular wave with a duty of 56 is continuously obtained. The contents of the shift register 2a are replaced by duty determination data from the CPUI only when changing the duty, and the value is 1/256 to 256/256.
(or 0/256 to 255/256).

Assume now that the digital data input to the data input terminal IN is data indicating the liquid level of the fuel tank of the vehicle. The data is obtained by converting the analog signal generated by the liquid level sensor into analog-digital (A-D) with a predetermined resolution.
) generated by an A-to-D converter. If the resolution is, for example, 1/16, the data will be ooooo
,oo.

01, 2 of 5 bits and 7 bits like 10000
Although it can be expressed as a base number, if the CPU 1 has an 8-bit configuration, data expressed using the lower 5 bits of 8 bits is sent to the CPUI in 8-bit units at a fixed period T, for example, 504 m.
It will be entered every second.

On the other hand, the deflection angle θ of the pointer of the cross-coil type meter 3 is determined by the following, where the currents flowing through the cross-coils 3a and 3b are (a, lb), and the present invention calculates this Ia, IbO ratio as the H level of the rectangular wave. L level ratio, that is, duty ratio R
DuT"l, and the deflection angle is determined by .

Therefore, if the duty determination data is directly selected using digital data with a resolution of 1/16 and a rectangular wave of the duty ratio is generated as described above, the deflection angle θ of the instrument pointer will be , θ. = o', θ
, =7.5', θ2-15'', θ+b=120', and the duty ratio R for each deflection angle is
The DUTY is as follows.

RDU? Y ”0 Rourv+ = 0.0897 Rourvt = 0.1659 Rnuyy+s = 0.9103 RDtl?□. = 1 When using the variable duty rectangular wave generation circuit 2 configured as shown in Fig. 3, the rectangular waveform with the above duty ratio is used. In order to generate a wave, the CPU 1 needs to output X for which X/256 is closest to the above duty ratio as duty determination data, and for this purpose, the CPU 1 stores the duty ratio corresponding to the digital data in read-only memory (ROM). It has a table for outputting decision data X.

In the above example, digital data duty determination data Xoooo
o.

All you have to do is prepare a table.

The CPU also calculates the difference between the duty determination data D selected by the digital data input at a constant period T and the duty determination data D0 selected by the digital data input last time, divides this difference into N, and calculates the corresponding The integral multiple of the value A divided into N is the duty determination data D, or the like.

Duty determination data D(1) to D(N) added to
is outputted at intervals of T/N and supplied to the variable duty rectangular wave generation circuit 2.

For example, certain digital data is input at time T0, and duty determination data D corresponds to this digital data. is being output at time T, digital data larger than the previous time is input, duty determination data corresponding to this digital data is Dl, and N is 4, then FIGS. 4 and 5 As shown in , the period from time T to time T2, when digital data will be input next, is divided into four equal parts, and each of the divided time points T is divided into four equal parts.
r + (TZ Tl) 14, Tr + 2
(TI-TI) 14, T, +3 (TI-T,
)14, D (,1)=D, + (DI −D
O)14, D(2) ==po +2 (DI -Do
)14, D(3) = Do + 3 (DI Do
) 14 duty determination data are output respectively.

With the above configuration, as shown in the flowchart of FIG. 6, when the CPU 1 takes in digital data from the data input terminal IN in step S1, it checks whether the digital data is different from the data that was taken in immediately before. is determined in step S2.

If there is no change in the data and the determination is No, step S
Return to step 1 and import the next digital data. When the determination is YES, the duty determination data D+ corresponding to the captured digital data is read from the table in the ROM in the next step S3, and the duty determination data D+ that was previously read from the table in the ROM is read out in the following step S4. It is compared with D0 to determine whether D,>Do.

When the determination in step S4 is YES, step S5
Then, (DI-Do) 14=A is obtained. After that, the process advances to step S6, where D(1)=D+
,+A,D (2)=D,+2A,,D (3)=D,
Find +3A for each. On the other hand, when the determination in step S4 is NO, the process advances to step S7, where (Do D
l) Find 14=A. After that, the process advances to step S8, where D (1)=D.

+3A,D (2)=D+ +2ASD (3)=D+
Find +A for each.

After finding D(1) to D(3) in step S6 or S8, the process proceeds to step S9, where it is determined whether or not time T/4 has elapsed. If the determination is NO, T/4 is The determination in step S9 is repeated until the time elapses. If the determination in step S9 is YES, the process proceeds to step SIO, where the duty determination data D (1
) is transferred to the shift register 2a of the variable duty rectangular wave generation circuit 2.

When the duty determination data is set in the shift register 2a, the comparison counter 2b is reset at the same time, and thereafter, the output of the magnitude comparator 2c has a constant duty ratio determined by the duty determination data set in the shift register 2a. This rectangular wave is repeatedly output until the duty determining data is changed, and is applied to the drivers 4a and 4b. Drivers 4a, 4b
are the H and L levels of the square wave, respectively, and the cross coil 3a
, 3b, the direction of the composite vector of the magnetic fields generated by each cross coil 3a, 3b will be in accordance with the duty ratio, and the meter 30 pointer will show a deflection angle in accordance with the digital data.

After that, in step Sll, wait for the elapse of time 2T/4 to transfer the data D(2) in step S12, and then wait for the elapse of time 3T/4 in step S13, and then transfer the data D(2) in step S13.
4, data D(3) is transferred. Furthermore, step S
After waiting for the time T to pass in step S15, the data D is stored in step S16.
, and return to step S1.

〔effect〕

As explained above, according to the present invention, the cross-coil type instrument can perform a predetermined display based on display information input in digital format, so that in an apparatus in which digital data is already prepared for digital display, In addition to easily converting the display to analog, if a microcomputer is installed for digital data processing, it can be easily implemented by adding a small amount of circuitry and changing the microcomputer's program. can get.

Further, since the pointer is smoothly driven at intervals obtained by dividing the pointer deflection angle between digital data inputted one after the other into a plurality of parts, the pointer does not move suddenly due to changes in the digital data.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a device according to the present invention, FIG. 2 is a circuit block diagram showing an embodiment of the present invention, FIG. 3 is a block diagram showing a specific example of a part of FIG. 1, 4 and 5 are explanatory views for explaining the present invention in detail, and FIG. 6 is a flowchart showing the operation of the central processing unit in FIG. 1. A...Cross coil type instrument, B...Duty determination data generation means, C...Variable duty square wave generation means, D...Driver means, IN...Data input means.

Claims (1)

[Claims] In a device for driving a cross-coil type instrument having a pair of cross coils arranged to intersect with each other, information displayed by the deflection angle of the pointer of the cross-coil type meter is input in the form of digital data. A data input terminal, and the digital data inputted to the data input terminal are captured, and the pointer deflection angle corresponding to each digital data is divided into a plurality of parts using the digital data captured one after another. Duty determining data generating means for generating duty determining data for determining the duty of a necessary square wave; and variable duty square wave generating means for generating a rectangular wave having a duty according to the duty determining data generated by the duty determining data generating means. and driver means for passing current through one of the cross coils at one level of the rectangular wave generated by the variable duty square wave generating means, and passing current through the other cross coil at the other level. A drive device for cross-coil type instruments.