JPH0251197B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention mainly relates to a control circuit for a display curtain device for a vehicle. More specifically, the present invention relates to a control circuit for a display screen device for a vehicle. More specifically, the present invention relates to a control circuit for a display screen device for a vehicle. This is a control circuit for simultaneous remote control using a single installed command unit. As an invention related to the present invention, the applicant of this invention previously issued Japanese Patent No. 1038732 (Japanese Patent Publication No. 55-28074).
(No.), a tap transformer is installed in the command unit and the display unit, and both tap transformers form an AC bridge circuit.The middle line (drawing line) of the bridge circuit is used as a command line to command the display position, and the command line is used as a command line to command the display position. We have proposed a display position circuit in which direction selection is performed based on the voltage value and phase difference applied to a thyristor that is controlled by input from a line. However, in such a circuit, although the indicator switches the secondary voltage of the tap transformer depending on the display position of the display screen, the voltage of each tap must be equal to the voltage of each tap of the tap transformer of the command unit. There is a disadvantage that the voltage of each individual tap must be strictly controlled when manufacturing the tap transformer, and when the display device matches the command and the bridge circuit is balanced, the center line (drawing line) They must be protected because residual voltage remains and they become susceptible to induced noise, which can cause malfunctions. In view of the above points, the present invention provides a control circuit for a display device for a vehicle, which is designed to solve such problems and eliminate such drawbacks.
The command voltage sent from the command unit and the reference command power supply voltage are switched by an analog switch in units of several tens of microseconds, and are sequentially converted into digital quantities at high speed by an analog-to-digital converter for balanced sampling. At the same time, each of the sampling data is added by a microcomputer, and from the averaged sum of noise etc., division is performed using the added data of the command voltage as the divisor and the added data of the command power supply voltage as the dividend, and the ratio is calculated from the quotient. By calculating this, errors caused by calculation are reduced and the display position can be detected stably. Hereinafter, embodiments of the present invention will be described in detail based on the drawings. First, before describing embodiments, in order to facilitate understanding of the present invention, the connection relationship between a command device and a display device used in the present invention will be described using FIG. 1. In the figure, IST is a command device that selects and commands a plurality of display positions, and DP ₁ , DP _{2 .} . . are display devices that move and display a display curtain based on commands from the command device IST. And U is the command unit IST and display unit
Voltage supply line that supplies the required voltage to DP ₁ , DP ₂ , etc., V is the voltage return line, U ₀ is the command power supply line, S is the command line, V ₀ is the voltage return line, This is the return line. FIG. 2 is a circuit diagram showing an embodiment of a control circuit for a display device according to the present invention, and only the parts necessary for explanation are shown. In Fig. 2, the same reference numerals as in Fig. 1 indicate corresponding parts, and a large number of indicators are connected to the command power supply lead-in line U ₀ and the command lead-in line S. In the embodiment, only one display is shown. In addition, in the following explanation, for convenience of explanation, the command power source in the example is
An example will be explained in which the voltage is 200V, the frequency is 50Hz, and the command tap voltage is applied at 5V intervals. Therefore, the display position of the display curtain is also up to 40. R ₁ and R ₂ are resistances for dividing the reference power supply voltage that is input via the command power supply lead-in line U ₀ ;
R ₃ and R ₄ are resistances for dividing the command voltage input via the command feed-through line S, and these resistors R ₁ and R ₂ are between the command power feed-through line U ₀ and the voltage return line V ₀ . The resistors R ₃ and R ₄ are connected in series between the command lead-in line (command line) S and the voltage return line V ₀ . C ₁ and C ₂ are coupling capacitors connected to the voltage dividing points of resistors R ₁ and R ₂ and to the voltage dividing points of resistors R ₃ and R ₄ , respectively. AS is an analog switch that inputs the above command voltage and the reference command power supply voltage and selects inputs I ₁ and I ₂ controlled by a switch switching signal from a microcomputer (described later). ADC is selected by analog switch AS. Output of analog quantity
An analog-to _- digital converter (hereinafter referred _to as A/
(abbreviated as D converter), the CPU uses this A/D converter
An 8-bit single-chip microcomputer (hereinafter referred to as microcomputer) that adds each sampled data from the ADC and divides the sum to find the ratio.This microcomputer CPU handles all control.
Built-in 3 input/output signal lines, memory, and timer. S ₀ , S ₁ ...S ₅ are printed on the display screen (not shown)
In the section representing 40 different destination names, enter the location from 2 ⁰ to
This display position switch S ₀ ^, S ₁ ...
When the switch is closed, _S5 outputs an electric signal of “1” with “signal present,” and when the switch is open, it outputs an electric signal of “0” with “no signal” to #1 to #40.
The screen is configured to output a curtain position (display position) signal up to. _S6 is a display position switch that stops the destination name at the correct position and, during operation, makes one hole in each section of the 40 destination names printed on the display screen to judge direction selection. This display position switch _S6 is configured to output an electrical signal "1" with "signal present" when the switch is closed, and to output an electrical signal "0" with "no signal" when the switch is open. ing. FR is the output port of the microcomputer CPU
A relay receives the output from _P14 and rotates a motor M, which will be described later, in the forward direction, and f is its normally open contact. BR is a relay that receives the output from the output port _P15 of the microcomputer CPU and rotates the electric motor M in the opposite direction, and b is its normally open contact. The electric motor M is a motor for moving the display screen, and its excitation wire ring is connected to an AC 100V voltage supply line and a voltage return line V via normally open contacts f and b of relays FR and BR. _C3 is a phase advance capacitor connected between the normally open contacts f and b and the connection point of the excitation wire of the motor M. Next, the operation of the embodiment shown in FIG.
This will be explained with reference to FIG. FIG. 3 is a waveform diagram showing the waveforms of each part of the control circuit of FIG. 2, and FIG. 4 is an operation explanatory diagram showing the relationship between the display position of the display curtain and the arrangement of the display position signal. First, in the embodiment shown in FIG.
indicates that it is stopped. As for the movement of each part in this state, the command power supply voltage AC 200V sent from the command unit via the command power supply lead-in line _U0 is resisted by the voltage dividing resistor.
The voltage is divided by R ₁ and R ₂ , and the DC component of the potential is cut off via the coupling capacitor C ₁ .
A voltage with a waveform as shown in FIG. 3a showing the potential at point A is output. On the other hand, the command voltage AC 50V at display position #10 sent from the command unit via the command line (command line) S is divided by the voltage dividing resistors R ₃ and R ₄ ,
The DC component of the potential is cut off via the coupling capacitor _C2 , and a voltage having a waveform as shown in FIG. 3b, which shows the potential at point B, is output. Here, the resistance values of the voltage dividing resistors R ₁ , R ₂ , R ₃ , and R ₄ are set so that R ₁ = R ₃ and R ₂ = R ₄ , respectively, and the points A and B in Figure 2 are set. The voltage ratio at is equal to the voltage ratio at the feedthrough. And, in the analog switch AS, the third
The control input terminal S receives a switch switching signal SCS that outputs each potential shown in Figures a and b from port _P12 of the microcomputer CPU, and the input is selected as input _I1 , and Figure 3 shows the potential at point C. It outputs a voltage with a waveform as shown in c. A/D that inputs the voltage from this analog switch AS to input terminal A.
The converter ADC converts the analog quantity given to the input terminal A into a digital quantity of 8-bit binary code by the conversion start signal CSS outputted from the output port _P10 of the microcomputer CPU, and outputs the data _DB0 ,
Output DB ₁ ...DB ₇ . After the conversion, the A/D converter ADC is connected to the microcomputer from the output terminal OB.
A conversion end signal CES is output to input port _P11 of the CPU. Upon receiving this conversion end signal CES, the microcomputer CPU inputs the digital quantity converted by the A/D converter ADC to input ports DB ₀ , DB ₁ ...DB ₇ , and adds it to the command power supply potential data in the internal data area. . Next, the microcomputer CPU selects the analog switch AS as the input _I2 by the switch switching signal SCS from the output port _P12 , performs A/D conversion using the same procedure as above, and stores the converted digital amount in the internal data area. Add to the command potential data. The series of operations up to now is repeatedly processed at high speed, as shown in FIG. 3c, and the command power waveform and the command waveform are each sampled. In addition, FIG. 3 d is a waveform diagram showing an enlarged circled part of FIG. 3 c, and the vertical axis voltage V×
2. The time on the horizontal axis is expanded to t×10. Then, the microcomputer CPU uses the command power supply potential addition data as a reference in order to judge the commanded display position based on the command power supply potential addition data and command potential addition data obtained by performing the above sampling a certain number of times. We are looking at the ratio of the command potential addition data. In other words, here, the value of the quotient is calculated by dividing the added data of the command power supply potential by the added data of the command potential, and the relationship between the display position and the operation of the display position switches S ₀ , S ₁ ...S ₆ with respect to the command voltage is determined by the microcomputer CPU. Indicates comparison data set in internal memory. As shown in the table below, install the microcomputer in advance.
Compare the quotient of the theoretical value obtained by dividing the power supply voltage 200V set in the memory of the CPU by the command voltage, and select a display position that falls within a certain range from the theoretical value as a 6-bit command display position in the internal data area of the microcomputer CPU. Set the code for

[Table] Here, the calculation result is an approximate value of "4000", and code #10 "010100" is set. After completing the setting, the microcomputer CPU clears the addition data in each internal data area and starts sampling again. In this way, the system is configured to constantly monitor the lead-through line and respond to changes in commands. Next, in explaining the operation of direction selection,
The relationship between the vehicle destination name written on the display curtain and the curtain position will be explained with reference to FIG. In this FIG. 4, #1, #2, #10...#40 indicate the display positions shown in the table above, and a, b, c, d,
e, f, g are display position switches S ₀ , S ₁ ,
For S ₂ , S ₃ , S ₄ , S ₅ and S ₆ , holes are drilled in the display screen at the positions marked with diagonal lines.
Indicates that the associated switch operates at that position. Now, the microcomputer shown in Figure 2 above
The code at display position #10 is set in the internal data area of the CPU as the command display position. On the other hand, at this time, the display curtain is stopped at the display position #10, so the output signals of the display position switches S ₀ , S ₁ ...S ₅ are "010100" as shown in the table above.
Microcomputer CPU input port P ₂₀ ~
Output on P ₂₅ . Then, the microcomputer CPU compares both codes, that is, the command display position "010100" and the display position "010100", and as a result, the sizes match, so relay FR and relay BR are not driven and the display is The electric motor M for moving the curtain is stopped. Next, the operation when the command display position is commanded to #1 shown in the above table in this state will be explained. First, the #1 command voltage of 5V is sent from the command device to the command lead-in line (command line) S. Then, by the series of sampling operations described above, the addition data is set in the internal data area of the microcomputer CPU. Here, the added data of the command power supply potential is almost the same as above, but the added data of the command potential is about 1/10 of the above, and the quotient obtained by dividing it is an approximate value of the theoretical value "40000", and #1 The code “100000” is set as the command display position. At this time, since the display position switches _S0 , _S1 ... _S5 stop at output signal #10, the code is "010100", and when compared, the latter is larger and the microcomputer CPU A reversal signal INV.S is output from the output port _P15 of the relay BR, and its normally open contact b is closed, thereby reversing the direction of rotation of the electric motor M for moving the display screen. By reversing the electric motor, the display curtain moves in the direction of the smaller display position, and when the display curtain reaches position #1, the display position switches S ₀ , S ₁ , . . . shown in the table above are activated.
The output signal of _S5 becomes "100000" and both codes match, and together with the operation of the display position switch _S6 , the operation of the relay BR is canceled and the electric motor M for moving the display screen is stopped. If the code of the command display position set in the microcomputer CPU is smaller than the code of the output signal of the display position switches _S0 , _S1 ... _S5 , the output port _P14 of the microcomputer CPU is
A normal rotation signal NRS is output from the relay FR, and its normally open contact f is closed, thereby rotating the electric motor M for moving the display curtain in the forward direction and moving the display curtain in the direction of the larger display position. Move to. When it reaches a predetermined position, the display position switch _S6 is operated and the relay FR is deactivated to stop the electric motor M for moving the display screen. As is clear from the above description, according to the present invention, the lead-through line is sequentially sampled using an A/D converter, the ratio of the reference command power supply voltage and the command voltage is determined, and the display position is determined. Therefore, it is possible to reduce the causes of malfunctions due to power fluctuations, residual voltage in the lead-in line, and noise, and the number of commands can be easily increased by adding an input section to the A/D converter. Therefore, the practical effect is extremely large. Furthermore, it is extremely effective in that a control circuit with a simple circuit configuration can be provided without using complicated means.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the connection relationship between a command unit and a display device, FIG. 2 is a circuit diagram showing an embodiment of a control circuit for a display device according to the present invention, and FIG. 3 is a block diagram showing each part of FIG. 2. FIG. 4 is an explanatory diagram showing the relationship between the display position of the display curtain and the arrangement of the display position signal, which is used to explain the operation of FIG. 2. IST...Command unit, DP ₁ , DP ₂ ...Display unit, AS...
...analog switch, ADC...A/D converter,
CPU...Microcomputer, _S0 , _S1 to _S6 ...
...Display position switch.

Claims (1)

[Claims] 1. In a vehicle destination display device consisting of a command device that selects and commands a plurality of display positions, and a plurality of display devices that move and display a display curtain based on the commands from the command device, an analog switch that selects the input and is controlled by a switch switching signal from a microcomputer, which inputs a command voltage to be used and a reference command power supply voltage;
An analog-to-digital converter that sequentially converts both outputs of the command voltage and command power supply voltage selected by the analog switch into digital amounts at high speed and performs balanced sampling, and this analog-to-digital converter and a microcomputer that calculates a ratio by adding each sampled data from the sum and dividing the sum, and the display position is detected by calculating the ratio by the microcomputer. Device control circuit.