JP2516459B2 - Crossed coil instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cross-coil type instrument generally used for vehicle speedometers, tachometers and other instruments.

[Conventional technology]

The cross-coil type instrument is generally composed of a display unit, a drive processing unit and a conversion unit, and the display unit is a so-called instrument body, in which a bobbin is internally provided with a movable magnet which is provided with a pointer shaft and is rotatable about the pointer shaft. The bobbin is formed by winding intersecting coils orthogonal to each other, and the conversion unit converts an input from the measured object into an electric signal (processing data) that can be easily processed by the drive processing unit. The instrument is driven by the output of the drive processing unit, which receives the processing unit data from the conversion unit and energizes the crossing coil in a predetermined manner. According to the state, it has a characteristic of a sine wave, and the other coil has a characteristic of a cosine wave, and supplies a voltage signal corresponding to the pointer indicating angle.
The supply voltage signal is a pulse signal, and using PWM (pulse, width, modulator), means for achieving the sine and cosine characteristics by changing the conduction time, and the sine by changing the magnitude of the supply voltage to the coil. , A means for achieving the cosine characteristic is known.

Further, in the above-mentioned cross-coil type instrument, processing is performed so that the pointer indication becomes zero when the power is turned off. Specifically, as shown in Japanese Utility Model Publication No. Sho 63-22264, a pack-up circuit with a capacitor is provided, and during analog processing, the converter output approaches zero due to the potential drop due to the capacitor discharge of the converter output side smoothing circuit. Along with that, the pointer is moved to zero by the backup circuit. Further, when the output of the conversion unit is a digital output, the digital data in the state when the power is off is uniformly zero. Therefore, even if a backup circuit is attached, the pointer may not return to zero. Therefore, when the output of the conversion unit is digital data, a data processing unit is provided between the conversion unit and the drive processing unit, and the output of the conversion unit is latched.
When the power is turned off, the latched data is output while being sequentially decreased, and the pointer is reset to zero.

[Problems to be Solved by the Invention]

The zero-reduction processing means performs zero-reduction of the pointer based on the output data (digital amount or analog amount) corresponding to the discharge characteristic of the smoothing circuit when the power supply is off, Also, if the output data when the power is turned off and the specified subtraction is performed, the subtraction is 1/2 → 1/4 → 1/8.
Is sequentially subtracted. By the way, the action of the synthetic magnetic field by the cross coil on the movable magnet having the pointer attached is maximum when the magnetic field directions of both are orthogonal, and the magnetic field force acting becomes weaker as the angle becomes smaller. However, the zero-reduction processing means described above merely energizes the crossing coils for sequentially guiding the pointer to the zero position without considering this point.

Therefore, in the present invention, in the zero-reducing process of the pointer, the cross coil is energized so that the magnetic force is strongly applied to the pointer, so that the prompt zero-zero is achieved.

[Means for solving the problem]

A cross-coil type instrument according to the present invention is a cross-coil that receives a status signal from a measurement target and converts the signal into predetermined processing data, and a cross-coil that operates a pointer at an indicated angle corresponding to the processing data. In the cross-coil type meter consisting of the drive processing unit that controls the energization amount of the, and the display unit that connects the pointer shaft to the center of the movable magnet installed in the cross coil and gives a predetermined pointer instruction, A detector,
It is provided between the power supply holding unit that supplies power for a certain period of time after the power is turned off, and the conversion unit and the drive processing unit. It is provided with a zero-reset processing unit that outputs processing data that is a reference angle that is a multiple of 90 degrees as a reference, and that further outputs processing data that sequentially returns the pointer to a zero instruction at 90 degrees to the drive processing unit. It is a feature.

Also, instead of the zero-reset processing unit described above, when the power is turned off, the processing data for sequentially returning the pointer to the zero pointing direction every 90 degrees from the pointer pointing angle at that time is output, and when the pointer pointing angle becomes 90 degrees or less. In addition, it is characterized by comprising a zero-reset processing section for outputting processing data of zero instruction to the drive processing section.

(Operation) Therefore, when the power-off state is detected by the power-state detection unit,
From the pointer pointing position at that time, the pointer pointing angle in the zero pointing direction is set to 0, 90 °, 180 °, or 270 °, whichever is closest, and then the pointer is turned 90 degrees in sequence. It moves every °, and always returns to zero while exerting a strong force on the pointer.

When the power-off state is detected by the power-state detection unit, the zero-pointing unit is moved to 90 ° or less from the pointer pointing position at that time in the zero-pointing direction. The processed data of is output and the pointer is zeroed.

As a specific process, if the output of the conversion unit (processing data) is an 8-bit digital numerical signal, 360 °
When the processing data is output based on a value obtained by dividing the value by 256, the processing data numerical values corresponding to the pointer indicating angles 0 °, 90 °, 180 °, and 270 ° are as follows.

0 ° ＝ 00 00 00 00 90 ° ＝ 01 00 00 00 180 ° ＝ 10 00 00 00 270 ° ＝ 11 00 00 00 Therefore, when the power off state is detected by the power state detector,
If only the upper 2 bits are valid when the power is off, the pointer moves to a position close to "0 °, 90 °, 180 °, 270 °" on the zero indication position side, and processing data for the next drive processing unit (return The zero-processed output is an output for moving the pointer every 90 ° from the pointer position.

Also, when the power is turned off, if the processing data is subtracted from the upper 2 bits at regular intervals, the pointer will be moved by 90 ° from the pointer position when the power is turned off, and when the upper bits are all "0". , When the lower bit is cleared, the needle needle returns to zero.

〔Example〕

 Next, examples of the present invention will be described.

<First Embodiment> A cross-coil type instrument according to a first embodiment of the present invention includes a conversion unit 1, a zero-reset processing unit 2, a drive processing unit 3, a display unit 4, a power supply state detection unit.
5, composed of a power supply holding unit 6, the conversion unit 1 receives an input signal (frequency signal) from the object to be measured and outputs processing data serving as an instrument instruction reference. It comprises an A / D converter 12. The F-V conversion unit 11 converts a measured amount from a measured object, for example, a pulse signal from a pulse generator attached to an axle, into a voltage signal proportional to the frequency when input at a frequency. The D conversion unit 12 divides the voltage signal into voltage levels and outputs a digital signal (processing data X) represented by, for example, an 8-bit binary number corresponding to each division. The zero-reset processing unit 2 is configured so that the lower 6 bits of the 8-bit digital signal from the conversion unit 1 are provided with an AND circuit, and the signal from the power supply state detection unit 6 is input to the other input of the AND circuit. ,
Normally, the processing data is output to the drive processing unit 3 as it is.

The drive processing unit 3 includes a ROM unit 31, a D-A conversion unit 32, and a drive output unit 33. The ROM unit 31 corresponds to the above-mentioned processing data X (digital signal) and cross coils x, y
Data that indicates the amount of electricity to be stored in the memory
The conversion unit 32 converts each output numerical value of the ROM unit 31 into an analog amount, and the drive output unit 33 energizes the crossing coils x and y corresponding to the analog amount. The display unit 4 is a so-called instrument body, in which a movable magnet is provided inside a bobbin formed by combining frames, winding cross coils x and y on the outer surface of the frame, and a pointer shaft protruding from the movable magnet. In addition, a weak magnetizing magnet for zeroing is internally provided in the leg used when the bobbin is attached to a measuring instrument or the like. The power supply state detection unit 5 detects the ON / OFF state of the ignition switch 7, and when the ON state is changed to the OFF state, cuts off the input from the measurement target of the conversion unit 1 and cuts the lower bit to the zero return processing unit 2. It sends an off signal. The backup power supply unit 6 is provided with a capacitor having an appropriate capacity, and when the ignition switch 7 is turned off, discharges the capacitor to supply operating power to each unit after the switch is turned off.

 Next, the operation of the instrument having the above configuration will be described.

When the input (frequency signal) from the object to be measured is received, the conversion unit 1 converts it into processing data X of a digital numerical signal proportional to the frequency of the input signal, and outputs this to the zero-reduction processing unit 2. When the zero-reset processing unit 2 receives the processing data X, it is output to the drive processing unit 3 as it is, and the drive processing unit 3 is energized in the x and y coils for the energization amount corresponding to the processing data X, and the pointer is the processing data. It is a pointer instruction corresponding to X.

When the power is turned on, the operation as described above is performed. However, when the power is suddenly turned off, a cutoff signal is sent from the power state detector 5 to the converter 1 and the zero-reset processor 2. The processing data X is a digital signal indicating a voltage level that is sequentially attenuated in response to the discharge of the smoothing capacitor of the FV conversion circuit, but the lower 6 bits due to the cutoff signal (“0” signal to the AND circuit). Becomes “0”, and only the upper bits are effectively operated and output to the drive processing unit 3.

Therefore, when the power is turned off, "270 °, 180 °, 90 °" corresponding to the upper bit near the zero position side in the processed data at that time
, 0 ° ”, for example, if 200 ° is instructed, 180 ° is instructed, and the zero return data (processing data after zero return processing) is output, and the pointer indicates 180 °, When the output of the conversion unit 1 is processing data of less than 180 °, the zero-returning data 90 ° is instructed, and 0 ° is sequentially instructed to zero the pointer.

<Second Embodiment> The second embodiment has basically the same configuration as the first embodiment except that the conversion unit 1'and the zero-reset processing unit 2'are different, and the conversion unit 1'is an object to be measured. The pulse signal from is counted by a reference pulse of a short cycle, and the reciprocal of the count value is output as processing data.
21 'and a latch unit 22', the subtraction unit 21 'normally processes the processing data through the latch unit 22' (when the ignition-off signal is "1") as illustrated in FIG. The data is output to the unit 3, but when the power is off, the upper bit is subtracted at every predetermined time determined by the frequency divider.

That is, when the power is turned off, the processing data immediately before the power is turned off, which has been latched by the latch 22 ', is input to the subtractor 21', and after a predetermined time elapses, the upper 2 bits of the processing data are subtracted. It is something to do. Therefore, as shown in the first embodiment, since the subtraction of "1" in the upper 2 bits corresponds to the pointer indication 90 °, it is for processing to indicate to the zero position by 90 ° from the indicated position when the power is turned off. The data is output from the subtraction unit 21 ', and this is output to the latch unit 2
It is latched at 2'and output to the drive processing unit 3, and the pointer is 9
It is moved to the zero position side by 0 °, and after a further predetermined time, it is 90 ° more than the value latched by the latch section 22 '.
By subtracting only the minute, it is output, and this process is repeated until all the upper 2 bits become "0", and after a predetermined time has elapsed, the lower bit is cleared and a zero position instruction is output to zero the pointer.

The present invention is not limited to the above-described embodiment, but the conversion unit 1 in the first embodiment is all digitally processed as in the second embodiment, and the zero-reset processing unit 2 is provided with a latch unit. However, although the processing data uses an 8-bit digital numerical value, it does not necessarily have to be 8-bit.

〔The invention's effect〕

In the cross-coil type instrument, the pointer zeroing process when the ignition switch is turned off is a zeroing operation for every 90 °, and a strong turning force is applied to the pointer to reset the pointer zeroing time. It is possible to reduce the size of the capacitor, which is a backup power supply.

[Brief description of drawings]

FIG. 1 is a simplified block diagram of the first embodiment of the present invention, and FIG.
FIG. 3 is a detailed view of the same, FIG. 3 is a simplified block diagram of the second embodiment, and FIG. 4 is a circuit side of the subtraction unit. 1,1 '... Conversion unit 11 ... FV conversion unit 12 ... A / D conversion unit 2,2' ... Zero-reduction processing unit 21 '... Subtraction unit 22' ... Latch unit 3 ... Driving Processing unit 31 ... ROM unit 32 ... DA conversion unit 33 ... Drive output unit 4 ... Display unit 5 ... Power supply state detection unit 6 ... Power supply holding unit 7 ... Ignition switch

Claims (2)

(57) [Claims] 1. An input of a status signal from an object to be measured,
A conversion unit for converting to predetermined processing data, a drive processing unit for controlling the energization amount of the crossing coil for operating the pointer at the indicated angle corresponding to the processing data, and a center of the movable magnet installed in the crossing coil. In a cross-coil type instrument consisting of a display unit for connecting a pointer shaft and giving a predetermined pointer instruction, a power supply state detection unit, a power supply holding unit that supplies power for a certain period of time after the power is turned off, and a conversion unit. It is installed between the drive processing unit and when the power is off, the pointer pointing angle is in the zero pointing direction from that time, and the pointer pointing angle is 90 degrees based on the zero pointing.
A crossing characterized by comprising a zero-reset processing unit that outputs processing data that is an instruction angle that is a multiple of degrees, and that further outputs processing data that returns the pointer to a zero instruction every 90 degrees to the drive processing unit. Coil type instrument. 2. An input of a status signal from an object to be measured,
A conversion unit for converting to predetermined processing data, a drive processing unit for controlling the energization amount of a crossing coil that operates a pointer at an indicated angle corresponding to the processing data, and a center of a movable magnet installed in the crossing coil. In a cross-coil type instrument consisting of a display unit for connecting a pointer shaft and giving a predetermined pointer instruction, a power supply state detection unit, a power supply holding unit that supplies power for a certain period of time after the power is turned off, and a conversion unit. It is installed between the drive processing unit and when the power is turned off, the processing data for returning the pointer to the zero pointing direction every 90 degrees from the pointer pointing angle at that time is output, and when the pointer pointing angle becomes 90 degrees or less. A cross-coil type instrument comprising a zero-reset processing unit that outputs zero-instruction processing data to a drive processing unit.