JPS6114517A - Integrating indicator - Google Patents

Abstract

PURPOSE:To cause no overflowing even with changing the display in km and the display in mile by making the number of digits of an integrating counter at least more than one piece than the number of display digits. CONSTITUTION:The pulse signal 1 corresponding to the running distance outputted from a sensor 1 is counted by a frequency dividing counter 3, then, the puls signal corresponding to the running distance of 1km unit is counted by an integrating counter 4. The count value thereof is displayed by a display device 7, after its arithmetic processing based on the conversion constant for displaying in km or mile by an arithmetic circuit 5. In this case the number of digits of the integrating counter 4 is made at least one piece more than the number of display digits of the display device 7, and even if the count value is multiplied or divided by a conversion constant for changing the km display and mile display, no overflowing is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic totalizer, and more particularly to a totalizer that can switch between displaying shrines and miles.

[Technical background of the invention and its problems]

In recent years, electronic display devices with improved information processing functions using microcomputers have been installed as automobile instruments, and in particular, conventional mechanical counter-type totalizers ( For example, Jikosho 5
9-2490, etc.), electronic totalizers that utilize non-volatile memory and digital display devices that can retain information even after power is cut off (for example, Japanese Patent Laid-Open No. 59-3411)
No. 2 etc.) have been used.

By the way, electronic instrumentation for automobiles improves various information processing functions.
It may be more convenient to display the information, and devices have been developed that can selectively display the lines or miles by switching a switch.

Conventionally, devices capable of switching the display have only a counter that counts the mileage in logical units, and an arithmetic circuit converts the mileage data into a conversion constant of 1 or 1.6.
is divided to display km or miles.

However, since the number of output digits of the counter and the number of digits displayed by the display device have been configured to have the same number of digits, the following problem may occur. That is, M A in the display device
If the X display is 99999.9km, the mileage is 11
When it reaches 00000k, the display device will display OOO000km. If you change the switch to display Miles, it will be Okm÷1.5 (conversion constant between km and Miles, same below) - 〇Mile, which is actually 100,000km÷1.6
= 62500 Miles, but OOOOO, OMi I
e is displayed. Similarly, if the MAX display on the display device is 99999.9Mi Ie, if you switch it to the mausoleum display, 99999.9M1leX 1.6 = 159
It will be 999.8km. However, since the number of displayed digits is 6, the highest digit "1" is deleted due to overflow, and the actual distance is 59999.8 km. If you switch this value to Mile display again, it will increase to 59999.8.
n÷1.6=37499.9M1le, which is different from the initial display value of 9.9999.9M1le. This is because the number of output digits of the counter that counts the distance traveled or the number of digits of the memory that stores this count value is the same as the number of digits of the display device, so if the count value is multiplied or divided by the conversion constant, an overflow will occur. Therefore, changing the display unit may result in inaccurate display values.

These drawbacks can be solved by having both a counter for b and a counter for mileage, but this increases the cost, and it is also possible to write two values, the value and the mileage value, in non-volatile memory each time. However, current non-volatile memory has durability issues, making it unsuitable for practical use.

[Purpose of the invention]

The present invention has been made based on the information in the above article, and provides an electronic totalizer that can perform b display and mile display by switching, and does not cause overflow even if the counted value is multiplied or divided by a conversion constant for switching. First, the object is to provide an electronic totalizer that can display accurate values.

[Structure of the invention]

The configuration of the present invention to achieve the above object is to convert the mileage of the vehicle into a pulse signal using a sensor, count the pulse signal with a counter, and display h or Mile by switching.
In an electronic totalizer that performs arithmetic processing and cumulatively displays the distance traveled, a frequency division counter that counts pulse signals from the sensor and outputs a pulse signal for each incoming cabal signal corresponding to a predetermined distance traveled. and an integration counter that counts the output pulse signal of this frequency division counter; and a display device that displays the distance traveled, and the number of digits of the integration counter is at least one more than the number of digits displayed by the display device.

[Embodiments of the invention]

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

FIG. 1 is a block diagram of an electronic totalizer showing one embodiment of the present invention. In the figure, 1 is a sensor for detecting the traveling distance. For example, when the vehicle travels 1 km, the speedometer cable connected to the vehicle's transmission rotates 637 times, and for each revolution of this cable,
It outputs pulse signals according to the distance traveled, such as generating 16 pulse signals. The pulse signal outputted by the sensor 1 corresponding to the traveling distance is waveform-shaped by a waveform shaping circuit 2 as required, and then counted by a frequency division counter 3. The frequency division counter 3 outputs one pulse signal to the integration counter 4 after counting a predetermined number of pulse signals corresponding to the distance traveled. Sensor 1 sends a pulse signal of 10292 (i.e. 637x16) when the vehicle travels 1k111.
Therefore, if the frequency division counter 3 outputs one pulse signal every time it counts 10,292 pulse signals, the count value counted by the integration counter 4 will correspond to the traveling distance in h units. . In this embodiment, the integration counter 4 is a 7-digit decimal counter. The arithmetic circuit 5 is connected to a changeover switch for b display and mile display (not shown), and calculates the count value of the integration counter 4 corresponding to b units using a conversion constant determined by the switching operation. In other words, in the case of b display, the count value is divided by 1, and in the case of mile display, the count value is divided by 1.
, divided by 6. In this way, the calculated count value is displayed on the display device 7 via the decoder/driver 6. The number of display digits of the display device 7 is at least one less than the number of output digits of the integration counter 4, and in this embodiment, it is a digital display device that displays six digits.

The control circuit 8 transmits the count value of the integration counter 4 to the nonvolatile memory 9 every time the frequency division counter 3 outputs a pulse signal. Non-volatile memory 9 is ignition switch SW
The 0 control circuit 8, which is a memory element that can retain memory contents even when the ignition switch SW, e is turned off,
'Even if the PFF is turned off, the voltage supply from the power supply circuit 10 is stopped for a predetermined period of time when the ignition switch SW is turned off so that the latest count value of the integration counter 4 inputted immediately before the PFF is transmitted to the nonvolatile memory 9. When the ignition switch SW is turned on, it transmits the vehicle mileage data stored in the nonvolatile memory 9 to the integration counter 4. The frequency division counter 3 is directly connected to the backup power supply 11 so that when the ignition switch SW is turned OFF, the number of pulses counted up to that point is reset and a truncation error does not occur. The other circuits are supplied with voltage from the power supply circuit 10, and the power supply circuit 10 is operated when the ignition switch SW is turned off.
When turned FF, the supply of voltage is stopped. Note that E is the vehicle battery, and L is the vehicle load such as lamps and audio.

In the above configuration, the pulse signal corresponding to the traveling distance outputted from the sensor 1 is counted by the frequency division counter 3, and then the pulse signal corresponding to the traveling distance in lkm is counted by the integrating counter 4. This counted value is then displayed on the display device 7 after being subjected to arithmetic processing in the arithmetic circuit 5 based on conversion constants for logical display or mileage display. At this time, the number of output digits of the integration counter 4 is smaller than the number of digits displayed on the display device 7 (one more), so the number of output digits of the integration counter 4 is 10 (100) as the mileage.
When counting 00km, the display device 7 shows 0OOOOOOk.
Display IIl.

However, when switching to the mile display, the count value of the integration counter 4 is processed as is in the arithmetic circuit 5, and the display device 7 displays 625,000M1le and 0M1le.
It is not le. Also, when the display device 7 is displaying 999999M1le as the MAX display, the totalizing counter 4 has one more digit than the display device 7, so it is 15999.
98 (that is, 999999X1.6)kll+, and does not hold an inaccurate integrated value such as counting 599998 km due to overflow due to display switching as in conventional devices.

Also, even if the ignition switch SW is turned off while the branch counter 3 is outputting one pulse signal and the control circuit 8 is writing the count value corresponding to the new mileage of the integration counter 4 into the nonvolatile memory 9. Since the power supply circuit 10 supplies voltage until the write operation is completed, the nonvolatile memory 9 always accurately retains the travel distance data up to that point.

Although one embodiment of the present invention has been described in detail above, it can be modified as appropriate within the scope of the gist of the present invention.

For example, in the present invention, the order of the conversion constant for switching the display of b and mile is 1, so in order to prevent overflow due to switching, the number of output digits of the counter is at least one more than the number of digits displayed by the display device. Must need, but.

If the order of the conversion constant increases in other conversions, the number of digits in the counter must be made larger than the number of digits in the display device.

Furthermore, in this embodiment, the lowest digit of the display device 7 is configured to display 1 kIn or I M i "I e, but by setting the generation ratio of the output pulse signal to the input pulse signal of the frequency division counter 3, .1 km, OIMile, Q, Qlkm, or 0.01M1le may be displayed.Also, the voltage output from the power supply circuit 10 is stopped when the ignition switch SW is turned off. It is also possible to adopt a configuration in which voltage is continuously supplied and display is always performed on the display device 7.

〔Effect of the invention〕

As described in detail above, according to the present invention, in an electronic totalizer that can perform b display and mile display by switching, even if the counted value is processed for switching, an accurate value can be obtained without causing overflow. We can provide an electronic totalizer that can display .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

Claims (1)

[Claims] In an electronic totalizer that converts the distance traveled by a vehicle into a pulse signal by a sensor, counts the pulse signal by a counter, performs arithmetic processing to display km or miles by switching, and displays the total distance traveled. A frequency division counter that counts pulse signals from a sensor and outputs a pulse signal for each input pulse signal corresponding to a predetermined travel distance, an integration counter that counts the output pulse signals of this frequency division counter, and a calculation of this integration counter. The value is in km or Mile
and a display device that displays the mileage according to the selection after arithmetic processing is performed using a value corresponding to the selection of one of the display devices, and the number of digits of the integration counter is at least one more than the number of digits displayed by the display device. A totalizer that is characterized by having more than one unit.