JPH09145401A - Electronic integrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable electronic integrator which is resistant to an error in a bit unit. SOLUTION: An electronic integrator is constituted in such a way that signals from a distance sensor (a distance detecting means) 1 are counted, and superordinate four digits of an integrated travel distance are written in and held by respective addresses of an EEPROM (a storage means) 5 as travel data with every unit travel distance, and subordinate two digits of the integrated travel distance are transferred to the next address with every unit travel distance by using the addresses themselves, and the travel data is written in and held, and the newest value is displayed by a display unit (a display means) 5. In the travel data, the respective digits are written in and held by a binary number of four bits. In its binary number (a numeric value to be converted), three bits in four bits in adjacent numeric values are converted by different converting methods. The travel data is displayed by performing inverse conversion of the converting methods.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic totalizer capable of measuring and displaying a traveling distance, and more particularly to an electronic totalizer having improved reliability.

[0002]

2. Description of the Related Art Conventionally, when this type of electronic integrator is used as, for example, an odometer of a vehicle, it is necessary to retain past traveling data even if a battery abnormality (voltage drop, battery removal, etc.) occurs. Therefore, a non-volatile memory is used (see Japanese Patent Laid-Open No. 59-196414).

In such a structure, when the traveling data is held in the non-volatile memory which is the storage means, it is determined whether or not it is possible to reliably determine whether or not the erroneous data (error) is written in the non-volatile memory. There was a problem with the reliability of the driving data. That is, in the case of performing the above determination, it is easier to find incorrect data as the number of written travel data is larger (since the incorrect data is a value that is far from the other correct data). Since the traveling data is written for each unit traveling distance, there is a large difference between the minimum value and the maximum value (latest value) of the positive data,
Finding false data is difficult.

Therefore, the applicant of the present invention writes only the upper digit of the traveling distance to each address of the nonvolatile memory as traveling data, and the lower digit uses the address itself,
In addition to reducing the number of writes to the non-volatile memory, in principle there are only two types of running data at each address, and we have proposed a method that improves the reliability of facilitating the detection of erroneous data with a distant value ( Japanese Patent Fair 5-65010
Reference).

FIG. 7 is an allocation diagram showing the configuration of the non-volatile memory M in the applicant's earlier application, which is 00 to 99.
For a total of 100 addresses, each address has 4 digits for storing the upper 4 digits of the mileage in binary number, and each address has 16 bits of b1 to b16,
Addresses 00 to 99 and bits b1 to b16 are written and read by the decoders D1 and D2 (or an encoder or a combination of a decoder and an encoder). In the same figure, it can be seen that the latest value of the travel data is "1/2/3/3" at address 56, and the latest value of the travel distance is "123356km".

[0006]

By the way, as shown in FIG. 8, when a noise occurs at the 57th position of the signal line of the decoder D1 and an error occurs at the address 56 during writing, the running data at the address 56 is Address before and after 55,5
This burst error is relatively easy to find because the value is far from the running data of 7.

However, as shown in FIG.
When the first bit of the signal line of the decoder D2 causes an error in the bit b1 during the writing of the data, the run data of the least significant digit is changed, and only the determination method of finding from the difference between the erroneous data and the correct data is used. This burst error cannot be found, so the latest value of mileage is incorrect "12335.
It becomes "5km" and an error of 1km occurs.

It is an object of the present invention to provide an electronic integrator which is resistant to an error in a bit unit and has improved reliability by adding a new writing method to the prior art of the present applicant.

[0009]

According to the present invention for solving the above-mentioned problems, the signal from the distance detecting means is counted and the upper digit of the accumulated traveling distance is stored in each address of the storing means as the upper digit of the accumulated traveling distance for each unit traveling distance. As the lower digit of the total traveling distance, the address itself is used to shift to the next address for each unit traveling distance, the traveling data is written and retained, and the latest value is displayed on the digital display means. In the electronic integrator for displaying, the traveling data is written and held as a 4-bit binary number, and the binary number is converted by a conversion method in which 3 bits out of the 4 bits are different in the adjacent numerical value of the converted numerical value. The traveling data is reversely converted by the conversion method and displayed on the display means.

Further, according to the present invention for solving the above-mentioned problems, the converted numerical value is obtained by converting the integrated traveling distance to 1
It is characterized by being a high-order digit of a hexadecimal number.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The signals from the distance sensor 1 are counted, and the upper 4 digits of the total traveling distance are EE for each unit traveling distance.
The data is stored in each address of the PROM 5 as travel data, the lower two digits of the accumulated travel distance are used by the address itself, and the travel data is written and held by moving to the next address for each unit travel distance. In an electronic totalizer that displays the latest value, each digit of the running data is written and held as a 4-bit binary number, and the binary number is converted by the difference of 3 bits out of 4 bits in the adjacent value of the converted value. It is converted by the method, and the traveling data is inversely converted by the above conversion method and displayed on the display unit 5. Even if an error occurs in the bit, the numerical value obtained by the inverse conversion based on it is those of the addresses before and after. Since it is a value far away from and, it is instantly known that there is an error.

The converted value is the upper 4 digits of the hexadecimal number obtained by converting the total traveled distance. By using the lower 1 digit of the address itself, the number of addresses can be reduced, and the storage means can have a small capacity. Get better.

[0013]

EXAMPLES The present invention will now be described based on the examples shown in FIGS. 1 to 4 relate to the first embodiment, and FIGS. 5 and 6 relate to the second embodiment.

FIG. 1 is a block diagram when the electronic integrator according to the present invention is used as an odometer of a vehicle. The distance sensor 1 which is a distance detecting means and includes an auxiliary circuit such as a waveform shaping circuit is It is installed on the wheel or axle of the vehicle, and outputs a pulse signal in response to the running, which is used as a distance input of the microcomputer 2 as a control means. The microcomputer 2 receives a distance input, counts the number of pulses, and writes / reads the traveling data of the EEPROM 5 which is a storage means for each predetermined unit traveling distance (for example, 1 km) via the decoders 3 and 4 which are input / output means. In the latter case, the display output to the display unit 7 which is a digital display unit and includes a display element such as a fluorescent display tube is performed by a predetermined method via the driver 6 which is a driving unit. 8 is a vehicle-mounted battery.

A method of writing data into the EEPROM 5 and outputting the display data to the display 7 will be described with reference to the layout diagram shown in FIG.

In the EEPROM 5, the upper digits of the traveling distance (for example, the upper 4 digits when displaying 6 digits, that is, 100 km unit) in the addresses 00 to 99 by the decoders 3 and 4 are one type or 2 types of the traveling data of each address 00 to 99. Type (In this embodiment, 2 of "1 ・ 2 ・ 3 ・ 3" and "1 ・ 2 ・ 3 ・ 3")
It is written every 100 km so that it is the case of the type), the microcomputer 2 sends a display output to the driver 6 based on this traveling data, and the display 7 displays the latest value. It is based on the same idea as the above-mentioned prior technology of the applicant.

In the present invention, the decoders 3 and 4 make the EEP
There is a difference in that the traveling data is converted from a decimal number into a binary number and written in the ROM 5 and in that it is inversely converted and read out. That is, as shown in FIG. 3, the conversion method is not a general conversion method ((a) in the figure), but a conversion method in which adjacent binary numbers that are the converted values have different binary numbers in 3 bits out of 4 bits. ((B) in the figure) is used for conversion, and this conversion is performed by the microcomputer 2. When the traveling distance is obtained, the traveling data stored in the addresses 00 to 99 of the EEPROM 5 is converted from the binary number to the decimal number by the inverse conversion of the conversion method, and a predetermined process (for example, Japanese Patent Publication No.
No. 65010, column 4, lines 27-42).

In FIG. 2, when the microcomputer 2 determines by the predetermined processing that the latest value is the traveling data of the address 56, the microcomputer 2 determines that the bit b16 to the address 56 of the address 56.
Driving data of b1 "0111/1100 / 1011.1.1
3 ”is obtained by the inverse conversion of the conversion method of FIG. 3B from“ 011 ”and the traveling distance is set to“ 123356 km ”and displayed on the display unit 7 by this and the address 56.

Here, as shown in FIG.
When the first bit line of the signal line of the input / output means 4 causes an error in the bit b1 at the time of writing, the running data “0111 · 1100.
101.21010 "is obtained by inverse conversion of the conversion method of FIG. 3 (b), and" 1.2.3.6 "is obtained. This value is the address 55 value" 1.2.3.3.3 "or address 57. It can be seen that the values are far apart (errors) having a large difference compared to the value "1 .2 .3 .2.", And it is possible to relatively easily find a bit error, which was conventionally difficult. Then, for the bits b4 to b1 having the large difference, the address 56 and the addresses 5 located before and after the address 56 are generated.
Comparing with 5, 57, the address 56 "1010"
3 bits match “1011” of the address 55 with 3 bits, but only match 2 bits with “1100” of the address 57.
It is presumed that the correct answer is that it should be written in “1011”, and this is rewritten into the correct answer, and the correct mileage is displayed on the display unit “12”.
"3356 km" is displayed.

FIG. 5 shows another embodiment of the present invention, in which the mileage is converted into a hexadecimal number and EEPRO is used.
M5 converts the upper 4 digits converted into the hexadecimal number of the mileage into addresses 0 to F by the decoders 3 and 4 for each address 0 to F.
There are one or two types of driving data (in this embodiment, "1.
E.2.3 "and" 1.E.2.2 "). Based on this running data, the microcomputer 2 sends a display output to the driver 6 and the display 7 Shows the latest value. That is, the mileage is "12
In case of "3447km", when converted to hexadecimal, "1 ・ E ・
It becomes “2,3,7”, and the upper 4 digits “1 · E · 2 · 3” are written in the address 7. Therefore, the traveling data of addresses 0 to 7 is "1.E.2.3", and the addresses 8 to F are "1.E.2.2".

Writing and reading to and from the EEPROM 5 are specifically performed by the conversion method shown in FIG. 6, so that the bits b4 to b1 are "1" at the addresses 0 to 7.
011 ”and the addresses 8 to F are“ 1100 ”. In this way, by converting the binary number in the adjacent hexadecimal number which is the number to be converted using the conversion method (FIG. 6) in which 3 bits out of 4 bits are different, the data showing the number “3” is obtained. Even if there is a 1-bit error, it will not be the adjacent number "2" (neither will be the adjacent number "4"),
On the contrary, even if there is a 1-bit error in the data indicating the numerical value “2”, the adjacent numerical value “3” does not occur (neither does the adjacent numerical value “1”), and the correct traveling distance is “123”.
447 km ”can be calculated.

According to this embodiment, the number of addresses is smaller than that in the above embodiments, and the EEPROM 5 has a small capacity, which contributes to cost reduction.

In each of the above-described embodiments, the error in units of address will not be described in detail, but the error situation is the same as in the conventional example (see FIG. 8), and the discovery thereof is relatively similar to the conventional example. Easily done.

The method of converting the converted numerical value (decimal number or hexadecimal number) and the binary number is the same as in FIG.
It is needless to say that the numbers are not limited to those shown in FIG. 6 and can be set arbitrarily, but it is possible to set the binary numbers adjacent to the numbers to be converted so that 3 bits out of 4 bits are different. is necessary.

In addition to the decoders 3 and 4 used in each of the above embodiments, the input / output circuit may be composed of an encoder or a combination of a decoder and an encoder, or control means (microcomputer 2). In the configuration in which the converted value and the binary number are converted (including inverse conversion), the input / output circuit can be simplified.

Furthermore, although the odometer has been described in each of the above embodiments, it goes without saying that it can also be used as a trip meter.

[0027]

According to the present invention, the signal from the distance detecting means is counted, and the upper digit of the accumulated traveling distance is written and held as traveling data in each address of the storing means for each unit traveling distance. In the electronic integrating meter that uses the address itself to shift the digit to the next address for each unit traveling distance, writes and holds the traveling data, and displays the latest value on the digital display means,
The traveling data is written and held as a 4-bit binary number, and the binary number is converted by a conversion method in which 3 bits out of the 4 bits are different between adjacent numerical values of the converted values, and the traveling data is converted by the conversion method. However, even if an error occurs in the bit, the numerical value obtained by the inverse conversion will be a value that is far from those of the addresses before and after, and thus an error will occur. It is possible to instantly know that there is, and thus it is possible to improve reliability by being resistant to bit error.

Further, the converted value is a high-order digit of a hexadecimal number obtained by converting the total traveled distance, the number of addresses can be small, and the storage means can have a small capacity, which can contribute to cost reduction.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a first embodiment of the present invention.

FIG. 2 is an allocation diagram illustrating a configuration of an EEPROM according to the embodiment.

FIG. 3 is a chart for explaining conversion between a decimal number and a binary number in the above embodiment.

FIG. 4 is an allocation diagram for explaining a bit error in the above embodiment.

FIG. 5 is an allocation diagram illustrating a bit error in the second embodiment of the present invention.

FIG. 6 is a chart for explaining conversion between hexadecimal numbers and binary numbers in the above embodiment.

FIG. 7 is an allocation diagram illustrating a configuration of an EEPROM of a conventional example.

FIG. 8 is an allocation diagram for explaining bit errors in the above.

FIG. 9 is an allocation diagram illustrating another bit error in the above.

[Explanation of symbols]

 1 distance sensor (distance detection means) 2 microcomputer (control means) 3,4 decoder (input / output means) 5 EEPROM (storage means) 6 driver (driving means) 7 indicator (display means)

Claims (2)

[Claims] 1. A signal from the distance detecting means is counted, and the upper digit of the accumulated traveling distance is written and held as traveling data in each address of the storage means for each unit traveling distance, and the lower digit of the accumulated traveling distance is stored in the address. In the electronic integrating meter which uses itself, shifts to the next address for each unit traveling distance, writes and retains the traveling data, and displays the latest value on the digital display means, the traveling data is 4 bits. Is written and held as a binary number, and the binary number is converted by a conversion method in which three bits of the four bits are different from each other in the adjacent numerical value of the converted value, and the running data is inversely converted by the conversion method. An electronic totalizer characterized by being displayed on a display means. 2. The electronic integrating meter according to claim 1, wherein the converted numerical value is a high-order digit of a hexadecimal number obtained by converting the integrated traveling distance.