JPH0776776B2 - How to drive the instrument - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

 The present invention relates to a method for driving an instrument.

2. Description of the Related Art As a conventional example of the present invention, a method for driving the cross coil type instrument shown in FIG. 5 will be described. Reference numeral 1 is a pulse generator that generates a pulse signal whose frequency changes according to the object to be measured. For example, the pulse generator 1 generates a pulse signal every time the vehicle travels a certain distance. 2 is an F / V converter,
The pulse signal generated by the pulse generator 1 is converted into a voltage value corresponding to the frequency (the cycle of the reciprocal of the frequency in some cases), and is mainly composed of an integrating circuit including a capacitor 3 and a resistor 4. Reference numeral 5 is an A / D converter, which makes the voltage value output from the F / V converter 2 correspond to one of several digital numerical values. Reference numeral 6 is a ROM, which designates an address based on the processed digital numerical value signal output from the A / D converter 5, and converts the analog current corresponding to the data stored in the designated address into the D / A converter. 7, amplifier 8
Output to the crossing coils L1 and L2, which are respectively wound at right angles via the crossing coils L1 and L2, surrounded by the crossing coils L1 and L2, and the pointer shaft with the pointer fixed at the tip The pointer is rotated by changing the direction of the magnetic field of the movable magnet 9 provided with, and the instruction of the meter is determined according to the processing signal. In this case, in the F / V converter 2, the voltage of the input pulse signal is charged in the capacitor 3 and the charge charged in the capacitor 3 is proportional to the value of the resistor 4 until the next pulse signal is input. Let it gradually discharge. The signal output from the F / V converter 2 is output as a sawtooth wave, but when the vehicle is traveling at low speed, pulse signals are generated at intervals, so the pointer vibrates finely. A so-called needle shake is likely to occur, and in order to prevent this, an integrating circuit (not shown) is further provided at the subsequent stage of the F / V converter 2.

[Problems to be Solved by the Invention]

By the way, the capacitor 3 and the resistor 4 which compose the F / V converter 2 have an error between components, and in particular, the accuracy of the capacitor 3 varies widely, and the actual output value of the F / V converter 2 and the designed output There is a case where the value is different, and to correct this,
A desired value was obtained by adjusting the value of the resistor 4, but it was very troublesome.

[Means for Solving the Problems]

The present invention aims to solve the above problems, by inputting a pulse signal whose frequency changes depending on the object to be measured, and by outputting a processed signal of a digital numerical value according to the frequency of this pulse signal, In the instrument driving method that determines the instruction of the instrument according to the processing signal, the latest numerical value of the processing signal is used as the operand, and the operand is output for each timing pulse output regardless of the pulse signal. A subtraction value corresponding to a fixed ratio of the calculated value is added, a constant is added to the result of the addition each time the pulse signal is input, and the result of this addition is used as the latest processed signal. It is what

【Example】

Next, FIGS. 1 to 4 in which the present invention is applied to a speedometer
An explanation will be given based on the embodiment shown in the drawing. The same parts as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 shows the overall configuration, in which 10 receives a pulse signal from the pulse generator 1 and outputs a digital numerical value according to the frequency of the pulse signal as a processing signal,
It is a control unit that performs processing according to the present invention. Then, in the subsequent stage of the control unit 10, a ROM6, which is a storage device that stores data for determining the amount of current flowing in the crossing coils L1 and L2 corresponding to the processing signal output from the control unit 10, D / A conversion The drive circuit 8 for driving the container 7 and the crossing coils L1, L2 is connected, and the ROM 6 stores the digital value corresponding to the processing signal from the control unit 10. Outputs digital numerical values and D / A
The converter 7 converts the digital numerical value into an analog numerical value and sends it to the drive circuit 8, and the drive circuit 8 outputs a current for driving the pointer as a drive signal. FIG. 2 illustrates the details of the control unit 10. Reference numeral 11 is a constant setter for inputting the pulse signal of the pulse generator 1 (see FIG. 1) and setting a predetermined constant. 12 is a timing pulse generator that constantly outputs a high frequency (for example, 1 KHz) timing pulse in a fixed cycle,
This timing pulse is output to each circuit (unit) in the control unit 10, and each circuit operates according to this timing pulse. Reference numeral 13 is a latch circuit that latches and outputs the numerical value of the latest processed signal of the control unit 10, which is the calculated value. Reference numeral 14 denotes an arithmetic unit that adds the processed value from the latch circuit 13 and the subtraction value determined by the subtraction value setting unit 15 with the adder 16 and outputs the result. Reference numeral 17 is an adder that adds the numerical values of the outputs of the constant setter 11 and the arithmetic unit 14 and uses them as processing signals for the control unit 10. Is output. Next, the operation will be described with reference to FIG. The constant setter 11 outputs an internally set constant only when the pulse signal is input from the pulse generator 1 (see FIG. 1), and adds the constant and the numerical value from the calculator 14 to the adder.
The pulse signal is a signal that does not have a specific period, so that its input is arbitrary. Therefore, there will be described a case where the pulse signal of the pulse generator 1 is not input, that is, the output of the constant setting device 11 is zero. The timing pulse generator 12 outputs a timing pulse having a constant cycle to each circuit, and each circuit performs a predetermined process of each circuit in synchronization with this timing pulse. When this timing pulse is output, the operand value held in the latch circuit 13 is output to the subtraction value setting unit 15 and the adder 16 of the arithmetic unit 14 (FIG. 3). The subtraction value setter 15 sets a value corresponding to a constant ratio of the operands output from the latch circuit 13 to a negative value and sets it as a subtraction value (FIG. 3). The subtracted value and the calculated value are added and output to the adder 17 (FIG. 3). The adder 17 adds the constant from the constant setter 11 and the numerical value from the calculator 14, but since the output from the constant setter 11 at this time is zero, the output of the adder 17 is the adder. The result output from 16 is output as is. This result is output as a new calculated value to the latch circuit 13 (Fig. 3).
At the same time, it is output to the ROM 6 as a processed signal (Fig. 3). Therefore, each time the timing pulse is output, the above process is repeated, and the output of the adder 17 has a monotonically decreasing value with a gradual slope. Next, the case where there is a numerical output from the constant setter 11, that is, the case where a pulse signal is input from the object to be measured to the control unit 10 will be described. When the pulse signal from the object to be measured is input to the constant setter 11 of the control unit 10, the constant setter 11 outputs the constant to the adder 17, and the constant and the result output from the calculator 14 are added. To be done. That is, the processing for increasing the output of the adder 17 which has been decreasing monotonically is performed (FIG. 3), and this output is also output to the latch circuit 13 as a new operand value in the same manner as described above. At the same time, it is output to the ROM 6 as a processing signal. The operation described above will be specifically described as follows. For example, it is assumed that the latch circuit 13 holds the calculated value “01010110”. When the timing pulse is output, this calculated value is output to the subtraction value setting unit 15 and the adder 16 in the arithmetic unit 14. When the calculated value is stored in, for example, a shift register in the subtraction value setting unit 15 and right-shifted by 2 bits, the calculated value "01010110" becomes "000101".
01 ”, and the two's complement“ 11 ”of this“ 00010101 ”
"101011" is used as the subtraction value, and the subtraction value is calculated by the adder 16. Therefore, the output of the adder 16 is the calculated value “0101011
The subtraction value "11101011" is added to "0" to obtain "01000001". That is, that this operation means, retrieves the negative value of 1 of 2 ² minutes by shifting the operand values to 2-bit right as a subtraction value of operand values, adding the subtracted value to the operand values It is those that the processing of the result output from the adder 16 is a value of 2 ^half of the minuend value (2 ² -1). The result “01000001” of the adder 16 is output to the latch circuit 13 as a new calculated value and to the ROM 6 as a processing signal. Then, if the pulse signal from the pulse generator 1 is input when the result of the adder 16 becomes “00000111” after the above-described processing is repeated 10 times, for example, a constant output from the constant setter 11, for example, “ 01010000 "and the result" 01000001 "of the adder 16 are added by the adder 17, and the result" 01010111 "of this addition is output to the latch circuit 13 as a new calculated value and to the ROM 6 as a processing signal. . When the above processing is repeated, the processing signal from the control unit 10 becomes a graph as shown in FIG. 4, and while the pulse signal from the pulse generator 1 is being input, the processing signal is output for each timing pulse. The signal becomes a monotonically decreasing curve with a gradual slope, and this is an approximately numerical calculation of the charging / discharging characteristics when an integrating circuit including a capacitor and a resistor is used. That is, this embodiment shows that the charging / discharging characteristics when converted by using the integrating circuit can be created by the numerical calculation without using the integrating circuit by the above-mentioned processing. The design value can be easily obtained without the need to adjust the precision variation of each component. In the above embodiment, the subtraction value setting circuit 15 uses a shift register or the like to set a value of 1 to a power of 2 as the subtraction value. formula It is also possible to adopt a configuration in which the processed signal converted corresponding to the above is output. Further, in the above embodiment, the two adders 16 and 17 are provided, but it is also possible to perform each processing at one place by operating one adder in a time division manner. .. Further, in the above-described embodiment, the cross-coil type instrument is taken as an example, but it can be used as a driving method for other instruments.

【The invention's effect】

The present invention inputs a pulse signal whose frequency changes according to the object to be measured, and outputs a processed signal of a digital numerical value corresponding to the frequency of the pulse signal, thereby giving an instruction of the instrument according to the processed signal. In the instrument driving method to be defined, the latest numerical value of the processed signal is used as the calculated value, and the calculated value corresponds to a constant ratio of the calculated value for each timing pulse output irrespective of the pulse signal. When an integration circuit is used, the subtraction value is added, a constant is added to the result of the addition every time the pulse signal is input, and the result of the addition is the latest processed signal. The charge / discharge characteristics of can be approximately calculated by numerical calculation, and a simple instrument driving method that does not require adjustment work can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining the overall configuration of the present invention, FIG. 2 is a block diagram for explaining the configuration of the control unit of FIG. 1, and FIG. 3 is for explaining the processing of the control unit of FIG. FIG. 4 is a flow chart, FIG. 4 is a graph for explaining the processing signal of the control unit of FIG. 2, and FIG. 5 is a block diagram for explaining the overall configuration of the conventional example. 1 …… Pulse generator 10 …… Control unit 11 …… Constant setter 12 …… Timing pulse generator 13 …… Latch circuit 14 …… Calculator 15 …… Subtraction value setter 16,17 …… Adder

Claims (1)

[Claims] 1. An input of a pulse signal whose frequency changes according to an object to be measured, and a processing signal of a digital numerical value corresponding to the frequency of the pulse signal is output, whereby an instruction of an instrument is displayed according to the processing signal. In the driving method of the measuring instrument, the latest numerical value of the processed signal is set as the calculated value, and the calculated value corresponds to a constant ratio of the calculated value for each timing pulse output regardless of the pulse signal. The method for driving an instrument is characterized in that a subtraction value to be added is added, a constant is added to the result of the addition each time the pulse signal is input, and the result of this addition is the latest processed signal.