JPH0690224B2 - Control device for crossed coil type instrument - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for controlling a cross-coil instrument dependent on a measurement signal, which converts the measurement signal into an integer proportional to the signal. A controller for a cross-coil instrument having a converter, a driver for forming a current for operating the cross-coil instrument from the integer, and a control logic circuit having the driver.

2. Description of the Related Art The cross-coil type measuring instrument can be used for indicating a non-electrical quantity, for example, the speed of a vehicle, by utilizing the known advantages of the measuring instrument. The known advantages of this are: low manufacturing costs, high and constant adjustment force over the entire indicated area,
And a large pointing area that can span four quadrants.
However, the cross-coil instrument has the disadvantage of having a small intrinsic damping, which adversely affects the indication of the measured quantity which is detected by the strongly varying measuring signal.

In particular, difficulties arise when the rotational speed of the Otto engine is to be measured using the measuring frequency derived from the ignition pulse.
This measured frequency is subject to strong short-term fluctuations, which can be caused by imbalances occurring during one revolution of the Otto engine and / or by deviations in the ignition timing.

An electrical converter is provided for converting the measuring frequency into a proportional measuring value and the current applied to the cross-coil measuring instrument from the measuring value, as in the case of measuring the rotational speed on the basis of the measuring frequency derived from the ignition pulse. When using a control logic circuit with a driver to form the, the disturbing fluctuations of the measurement signal are almost uncontrolled and are indicated as they are.

The converter can be composed of a period measuring circuit of the measuring frequency and a subsequent divider in order to produce a measuring value proportional to the measuring frequency and thus to the rotational speed of the Otto motor. The measured value formed by means of the divider is supplied to a control logic circuit, which for each measured value produces a current which can be supplied to the two normal coils of the cross-coil meter, The magnitude of this current is the magnitude of the deflection of the pointer which is proportional to the measurement signal (measurement frequency in this case) or the measurement value.

From US Pat. No. 4,230,984 (DE 3003151 A1) is known a device which is likewise capable of processing the measuring frequency. With this device,
The current supplied to the cross-coil instrument is formed from the measured signal according to the following function. That is, according to this function, the deflection of the pointing needle, which is proportional to the measurement signal, is formed over a wide angle. A block diagram of this device is shown in FIG. This device has a digital frequency measuring instrument with a speed sensor, a buffer, a tacho-register, a storage register and an inverter as a converter connected downstream to the storage register. A speed sensor that detects the vehicle speed forms a pulse train that is proportional to the speed. This pulse, which represents the frequency, ie the input quantity, is fed to the buffer, from which it is further fed to the serial tachometer. The serial tachometer is preferably a digital frequency measuring instrument.
Special points, the transducer, the lower 7 bits stored in the storage register is that the 2 ^{0-2 6} is supplied. The converter supplies a signal to a function generator for generating an output signal, the output signal varying as a tangent function of the supplied signal in each one of a number of delimited cross-coil instrument indicating areas. To do. The function generator applies a signal to the control logic circuit via the duty-actor generator, which control logic circuit controls the two indicator drives. The control logic is then controlled by the upper three bits of the storage register. The control logic circuit acts on the power supply to both coils of the cross-coil instrument, and thus on the operating region of this instrument.
Similarly, the control logic circuit provides a variable duty factor current to one of both coils and a constant current to the other coil.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above device, in detail, how to generate the current applied to the cross coil type meter from the measurement frequency as the measurement signal by using the control logic circuit having the converter and the driver. Regardless of the setting, the disturbing effect of the measurement frequency fluctuation has a direct effect. This is because the above functions are only used to create a proportional relationship between the measurement signal and the pointer.

Therefore, the known control systems for cross-coil instruments cannot be used at all for indicating highly variable measuring signals, in particular for indicating the rotational speed of an Otto engine.

In order to be able to use a cross-coil instrument, despite its low self-damping, for indicating a measurand detected with a strongly disturbed measuring signal, such as the measuring frequency of an Otto engine, , It has been proposed to smooth the current generated by the driver (which is added to the crossed coil instrument) using a filter. But this method
The disadvantage is that at least one relatively expensive bipolar capacitor must be provided for each filter. This method is also disadvantageous in that the condenser or filter is large in structure. The above drawbacks are all the more significant because the smoothing means are provided for each of the two currents supplied to the cross-coil type instrument, which doubles the cost and space for the smoothing means. Further, deterioration of the accuracy may occur due to deterioration of the capacitor.

The object of the invention is of the type mentioned at the outset such that a measured quantity represented by a strongly disturbed or fluctuating measuring signal can still be read, i.e. the measured quantity is stable and accurately indicated. It is an object of the invention to provide a device for controlling a crossed coil instrument depending on a measurement signal.

This object is according to the invention: a) a quadratic digital delay element is provided between the converter and the control logic circuit, and b) the quadratic digital delay element is It is composed of two first-order digital delay elements and a program controller connected to each other, and c) the first-order digital delay elements respectively calculate an intermediate value (azn) and a remainder value (R1n) of attenuation according to the following equation: azn _{= [(azn -1) (d} -1) + (R1n -1) + am] / d ( calculated remainder results remainder value R1n) instantaneous measured value (am), the preceding attenuation calculated by the run of the intermediate calculated from the value (azn _-1) and the preceding calculated remainder value in the run (R1n _-1), where d is the damping coefficient,
It is configured and solved.

In the present invention, the intermediate value calculated in the preceding run and the instantaneous measured value are weighted with a damping factor (eg 4). As a result, even if a measurement value including noise that causes a sharp shake of the pointer is input, the effect can be mitigated. Also, in order to avoid the occurrence of an error due to the accumulation of surplus values, the surplus value is also taken into consideration in the calculation. The intermediate value calculated in the preceding run is stored in the preceding value register 21, and the remainder value calculated in the preceding run is stored in the remainder value register 20 and supplied to the adder 11, respectively. At that time, the multiplication of the preceding value is performed by multiple addition by passing through the addition stage a plurality of times via a loop. The median of the weighted preceding runs, and
The remainder value and the instantaneous measurement value are added, and the addition result is divided by the shift register 18. The new calculation result is supplied to the digital delay element of the next stage and stored in the preceding value register and the remainder value register.

Embodiment Next, the configuration and operation of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a period length measuring circuit device is shown by 1. The measuring frequency f _M ess is supplied to the input side 2 of this device. The measurement frequency sampled cyclically in the circuit arrangement 1 is converted into the reciprocal of the measurement frequency, for example by counting the cycle length using a fixed clock frequency. From this reciprocal, this number is also fed to the divider 3 to form a measured value which is also proportional to the measured frequency.

Therefore, the cycle length measuring circuit device 1 and the divider 3 constitute a converter, and the converter converts the measured frequency into a measured value proportional to the measured frequency. The measured values are shown as integers using binary numbers. The minimum value of this binary number is 2 ^0.

This measured value is the second-order digital delay element (PT ₂ element).
4 is supplied. In this element, undesired short-term noise of the measuring signal is filtered. In determining the circuit constant of the second-order digital delay element, it is premised that the noise has a frequency higher than the frequency of the change in the measured amount. In this digital PT ₂ element, the measured value, the preceding measured value and the remainder value are delayed and added a plurality of times, and division is performed at the end of each run. In this way, the digital PT ₂ element makes it possible to obtain a filter characteristic having sufficient insensitivity to noise.

The measurement value thus modified is fed to the control logic circuit 5, which normally produces two currents from the measurement value, which currents are supplied via the conductors 6 to 9 of the cross-coil meter 10. It is supplied to a coil (not shown).

The value indicated by means of the cross-coil type instrument 10 is accordingly proportional to the measuring frequency of the input 2 in the adjusted state, and neither disturbing fluctuations of the measuring frequency nor slight fluctuations of the measuring frequency are indicated. In other words, the instructions are accurate, stationary, and legible.

The second-order digital delay element (PT ₂ element) provided for this purpose is mainly two cascaded,
It is composed of a primary delay element (PT ₁ element) equipped with a remainder value processing circuit. Equipped with such a residue value processing circuit
The PT ₁ element is shown in FIG.

That is, the first-order digital delay element shown in FIG.
It constitutes one stage of a quadratic two-stage digital delay element as shown in FIG.

The first-order digital delay element is AND gate 13 and OR gate 1
It has an adder 11 for performing a plurality of additions via a loop 12 which is led to a register 15 via 4. The output of the register is connected to the first input 16 'of the adder. Register 15 also has AND gate 16 and OR gate 1
It is possible to supply the am binary measurement via 4 and.

The output side of the adder output side 11 is connected to the shift register 18 via another AND gate 17. From the output side of the shift register, the remainder value register 20 and the preceding value register 21
Lead wire 19 is led to. The output of each of the two registers is connected to the second input of the adder via an AND gate 22 to 23 and a common OR gate 24.

Another connecting line is connected from the output side of the shift register 18 via the intermediate storage device 26. The intermediate value of attenuation is sent out from this output.

This first-order digital delay element is a program controller 27
Is automatically controlled by consecutive runs. At that time, multiple (multiple) additions are performed during one run, and division at the shift register is performed at the end of each run. For this reason, the program controller acts in particular on the AND gates 13, 16, 17 and all registers.

Thereby the first-order digital delay element was calculated between the measured value am and the preceding run. And according to the following formula consisting of the remainder value R1n ₋₁ and the damping constant damping ratio d, Or calculate the remainder R ₁ n. I.e. Next, the detailed programming process will be described.

First, as can be seen from FIG. 3, the second-order digital delay element shown therein has two stages of the first-order delay element shown in FIG.
It consists of one continuous connection. The first stage is designated 28 in FIG. 3 and the second stage is designated 29. The affiliated program control device 30 is the program control device 27 of FIG.
Is configured for one stage as well.

The output side of the first stage for the at the same time constitutes the input side of the second stage. On the output side of the second stage Appears. This instruction value is the control logic circuit 5 shown in FIG.
Is supplied to.

The second stage 29 shown in FIG. 3 essentially forms the following relationship, like the first stage.

Ie: In this equation, Is the residual value of the second stage calculated during the preceding run n-1, Is the indicated value calculated during the preceding run n-1.

Assuming damping d = 4, binary 2 bit words (actually 10
The values shown in the following table are calculated for the second-order two-stage digital delay element.

In the table, n in the left column shows the order of each run, and the measurement value am is shown in the column to the right of the run, where am is constant in the eight program steps, and the three columns to the right of it are am. The values formed in the first row are shown, and in the last three columns the values formed in the second row are shown.

For the operation of the first stage, it is assumed first that the program controller starts when the process n = 0. At this point, the value 0 has been stored in the preceding value register 21 and the remainder value register 20 has the value .00. (It should be noted here that the remainder values R ₁ and R ₂ are digits to the right of the decimal point.) Register 15 now contains the measured value am
= 01 is stored. At this time, the adder is the sum To the calculated value Multiple times Add until you reach. The surplus value Rn _-1 reached in the preceding program cycle is also always added at the same time. However, this remainder value may be added separately in another embodiment. In any case, after the multiple addition as described above in the shift register 18, the value is Is obtained, and by shifting this value to the right, d =
Divided by 4. That is, this value is shifted to the right twice by the shift register. This ends the 0th run And the residual value R ₁ = 01 is obtained. The second stage 29, to which these values are supplied, is And the residual value R ₂ = 0 in the second stage, Is still 00. For the next run n = 1, And the remainder value of the first stage is equal to 10. Such a process
After the fourth run (n = 3) Is repeated in the same manner until reaches the measured value am. However, in that case, the second stage first calculates the residual value R ₂ = 01. n =
After 6th, that is, after the 7th run, Is the measured value.

What is important is that the indication values likewise change only if disturbing pulses occur during these runs, while their effects are averaged out in the case of relatively short disturbing pulses. The advantage here is that an indication value then only occurs once at the output side of the second stage after that, which indication value continuously changes in the correct direction according to the measured value, that is to say in the cross-coil form. The pointer position of the instrument can be determined with almost no fluctuation.

The present invention will be supplementarily described below. In the conventional normal electric pointing device, due to the mass of the movable member, the electric pointing device itself has inertia, and no special damping is required. However, in the case of electronically controlled cross-coil instruments, this "natural" damping is absent, so that for good visibility of the rapidly fluctuating measurements, special damping must be done. I won't.

In the example shown in FIG. 1, the signal to be attenuated consists of a frequency which varies in proportion to the measured value. However, this frequency is so low that it is not possible directly to obtain a numerical value that can be used in the calculation process. Therefore, the first part of the converter first forms the reciprocal of the frequency, ie the numerical value proportional to the period time. For this purpose the incoming signal is sampled at a constant measuring frequency, one value is generated for each measuring clock, which value is inverted in the second part of the converter. In this way, a continuous value that is directly proportional to the measured value is obtained. However, since the formation and inversion of the numerical value must be processed with a finite number of digits, a remainder (residual value) is always generated. This remainder is not significant for the individual numbers, but it accumulates over time and therefore cannot be ignored.

It can be seen that there can be a large difference in the two consecutive numbers generated by the transducer, which leads to a violent deflection of the pointer. Therefore, the number representing the preceding measurement is multiplied by one less than the damping factor, eg 3, and the new number is added unchanged, and the resulting value is divided by the damping factor, eg 4, To do. In other words, only three-fourths of the "old" value of the preceding run and one-fourth of that of the "new" value contribute to the calculation of the values required to control the cross-coil instrument. The damping factor in this case (here 4) can be chosen freely, so that the influence of the new value on the old value can be set within wide limits.

The circuit shown in FIG. 2 allows the calculation of the claimed formula to be performed once for each measurement clock. The instantaneous measurement value is added to the old measurement value and the sum is divided by a predetermined damping factor. The old measurement is multiplied by a number that is one less than the predetermined damping factor.

Further, the remainder generated by various arithmetic operations is processed.
That is, the remainder (residual value) generated at each measurement clock is accumulated until it becomes larger than the lowest digit of the measured value as a whole, and when the accumulated remainder value becomes larger than the lowest digit, the lowest digit is set to 1.
Only increase.

The portion shown in FIG. 2 collectively forms a first-order digital delay element. FIG. 3 shows a state in which two delay elements are connected to each other to form a secondary digital delay element. At that time, the same calculation processing is performed for the first attenuation and the second attenuation. The damping characteristics can be controlled arbitrarily by appropriate selection of the damping coefficients in the two digital delay elements.

As described above, the measured value is processed by the first-order digital delay element as follows. That is, the value of the measurement clock (n) is added to the value of the preceding measurement clock (n-1) multiplied by a value one less than the damping coefficient, and the sum is divided by the damping coefficient. In this way, a new calculated value is obtained. This newly calculated value is used to control the instrument and is also stored in place of the value of the preceding measurement clock (n-1) so that the measurement clock (n + 1) will be used in the next calculation.
It is processed with the numerical value of. The calculation for each new value (measurement) is repeated cyclically.

The division of the sum by an attenuation coefficient (eg 4) is done in the shift register 18. The newly calculated value and the resulting remainder are then transmitted via line 19 to registers 21 and 20, from which they are called up in the next calculation cycle. The multiplication of old numbers is done by multiple addition via loop 21.

The purpose of the two-stage damping is to prevent control pulses that could cause nervous oscillations of the indicator needle. Such control pulses can be triggered by rapid measurement changes or external disturbance pulses. However, the two attenuating circuits are similarly configured in that they process each input numerical value in the same way.

Effect The essence of the invention consists in eliminating the disturbing fluctuations of the measuring signal by converting this measuring signal into a proportional measuring value by means of a converter and then adding the measuring value to the control logic circuit. This causes the current to be applied to the cross-coil meter by the control logic circuit with the driver to be already smoothed and generated. By the secondary digital delay element (PT ₂ element) provided by the present invention, the disturbing fluctuation of the measured value is almost eliminated in a short time, and the change of the measured quantity and the deflection of the needle of the crossed coil type instrument for displaying it. There is no significant delay between. The accuracy of the entire device for controlling the crossed coil instrument is totally retained. I mean,
During the digital processing of the measured values for the formation of the second-order delay, the residual values which occur during the division of the measured values into integers are detected by means of the residual value storage and are associated with the processing of the measured values. is there. At that time, the measurement numeric and is summer it is a premise is Intejiya (2 ⁰ or higher power of 2) that is integral either case, generate this integer using a converter and treated with control logic It is becoming like this. Due to the digital formation of the quadratic delay, the high cost for smoothing the current to be supplied to the cross-coil instrument or the structural damping measures of the cross-coil instrument itself can be dispensed with, the latter being the latter. The treatments described above may cause undesired inertia and aperiodic indicating characteristics.

With the configuration described in the embodiment section, the circuit technology cost is significantly reduced.

[Brief description of drawings]

FIG. 1 is an overall block circuit diagram of an apparatus for controlling a crossed coil type instrument depending on a measurement frequency, FIG. 2 is a block circuit diagram of a first-order digital delay element (PT ₁ element), and FIG.
FIG. 4 is a block circuit diagram of a secondary digital delay element forming the attenuator in FIG. 1, and FIG. 4 is a block diagram for explaining a known cross coil type meter. 1,3 ... Converter, 4 ... Second-order digital delay element, 5
...... Control logic circuit, 20 …… Remainder value register, 21 …… Preceding value register, 28,29 …… Primary digital delay element.

Claims (2)

[Claims] 1. A device for controlling a cross-coil measuring instrument depending on a measurement signal, the converter converting the measurement signal into an integer proportional to the signal, and the cross-coil measuring instrument based on the integer. In a control device for a cross-coil type instrument having a driver for forming an operating current and a control logic circuit including the driver, a) between a converter (1, 3) and a control logic circuit (5) To 2
A second digital delay element (4) is provided, and b) the second digital delay element (4) includes two first-order digital delay elements (28, 29) connected to each other and a program controller ( 27) and c) The first-order digital delay elements (28, 29) respectively calculate the intermediate value (azn) and the remainder value (R1n) of attenuation according to the following equation: azn = [(azn _-1 ) (d -1) + (R1n _-1 ) + am] / d (the remainder of the calculation result is the residual value R1n) The instantaneous measured value (am), the intermediate value of the attenuation calculated in the preceding run (azn _-1 ) and the preceding It is calculated from the remainder value (R1n _-1 ) calculated in the run, where d is the damping coefficient,
A control device for a crossed coil instrument, characterized in that 2. A) each of said delay elements (28, 29) has an adder (11) with two inputs (16, 25) and one output, and b) A register (15), an OR gate (14) and two AND gates (13, 16) are pre-connected to the input side (16) of 1, and c) to the second input side (25). , OR gate (24), two
The AND gates (22, 23), the remainder value register (20) and the preceding value register (21) are pre-connected, and the AND gate (17) and the shift register (1
8. The control device for the crossed coil type instrument according to claim 1, wherein 8) is connected afterwards.