JPH03272605A - Datum storing device - Google Patents

Abstract

PURPOSE:To simplify structure of a data storing device and reduce a cost by writing measured datum to a nonvolatile memory and changing an address for writing in turn on arriving datum-writing and erasing times to a fixed data address at a fixed time. CONSTITUTION:A measured datum is written to a fixed data address a1 in a nonvolatile memory 24 by a writing means A and a reading-controlling is performed by a reading means B. Thereafter, writing and reading of data are repeatedly performed to said data address a1. Thus, on arriving said writing times at a fixed time, the data address a1 of the data memory in the nonvolatile memory 24 is changed by a data address-changing means C and writing and reading actions are performed in a new data address. Thereafter, said action is repeated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a data holding device used, for example, in a lift control device for a working machine, and more specifically, to a data holding device for frequently writing and erasing data. Regarding equipment.

[Conventional technology]

As the conventional data holding device, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-312907,
Data that is written and erased relatively few times is electrically stored in EEPROM, which is a non-volatile memory, so that it can be written and erased freely, and data that is written and erased many times is stored in low-power static RAM, which can be used as a power backup such as a simple capacitor. It was configured to hold data using means.

[Problem to be solved by the invention]

Although the EEPROM can store written data for a long period of time without using any power backup means, there is a certain limit to the number of times it can be written due to the characteristics of its semiconductor element. Data that has been written many times is stored in static RAM.

However, the above-described conventional structure has the drawback that it requires a power backup means, such as a capacitor and a switching transistor, in addition to the memory element, making the structure complicated.

The present invention reduces the number of parts through rational improvement,
It is an object of the present invention to provide a data holding device that can simplify the structure and reduce costs.

[Means to solve the problem]

The characteristic configuration of the present invention includes a writing means for writing measurement data into a predetermined data address of a non-volatile memory that can be electrically written and erased, a reading means for reading out the data, and a writing means for writing and erasing data at the data address. The present invention further includes data address changing means for sequentially changing the write data address when the number of times reaches a predetermined number.

[For production]

Measurement data is written to a predetermined data address of the non-volatile memory by the writing means, and read and controlled by the reading means, and thereafter data is repeatedly written and read from the data address.

Then, when the number of writes and reads reaches a predetermined number,
The changing means changes the data address for storing data in the nonvolatile memory, and the write/read operation as described above is executed at the changed data address. Thereafter, such operations are repeated.

〔Effect of the invention〕

Therefore, according to the present invention, even data that is frequently written and read can be stored in a nonvolatile memory that can be written and erased electrically, and a static RAM can be equipped with a power backup means. There is no need for this, the number of parts can be reduced, and costs can also be reduced.

〔Example〕

Hereinafter, embodiments of the present invention will be explained based on the drawings.

As shown in Figure 5, an engine (1) is placed at the front of the vehicle body, and a transmission case (3) to which power is transmitted from the main clutch housing (2) connected to the rear of the engine (1) is attached to the vehicle body. This transmission case (3
An agricultural tractor is comprised of a front wheel (4) and rear wheels (5) to which transmission power is transmitted from the front wheel (4) and rear wheels (5).

This agricultural tractor has a rotary tiller (R) at the rear end of the vehicle body.
) is provided with a lift drive and a lift control device so that plowing work can be carried out by connecting the plows so that they can be raised and lowered.

That is, a pair of left and right lift arms (7) that are driven up and down by a hydraulic cylinder (6) are provided on the upper part of the transmission case (3), and a two-point link mechanism (8) is installed on the rear surface of the transmission case (3). The rotary tilling device (R) is connected via the two-point link mechanism (8) and the lift arm (7).
are connected in a suspended state via a lift rod (9).

In addition, a control box (
12) is attached, and when performing tillage work, the rotary tiller (R) is raised and lowered by a control mechanism built into the control box (12).

As shown in FIG. 1, the control box (12
) is equipped with a potentiometer-type plowing depth setting device (14) operated by a dial (13), and the rotary tilling device (R) is equipped with a potentiometer-type plowing depth setting device (14) that detects the swinging posture of the rear cover (15). A sensor (16) is provided, and voltage signals from each are sent to an A/D converter (17), (1
After being converted into a digital signal in step 8), it is transmitted to a control device (19), and the control signal from the control device (19) is transmitted to a driver (22) for controlling the hydraulic cylinder (6). By being configured so that the signal is output to the solenoid valve (23), during tilling work, the rotary rotation is continued until the setting signal from the tilling depth setter (14) and the detection signal from the tilling depth sensor (16) are balanced. The tilling device (R) is set to move up and down.

This control system is equipped with an EEPROM (24) that stores and holds data etc. from the tillage depth sensor (16) when the rotary tiller (R) is raised to a predetermined level as a control standard. ) is the data bus (2
5) and the control device (19) via the address bus (16).
) is linked. The EEPROM (24) is a nonvolatile memory that can be electrically written and erased,
Although the memory content can be retained for a long period of time even after the main switch (27) is turned off, there is a certain limit to the number of times it can be written (approximately -100 times) due to the characteristics of a semiconductor device. Therefore, writing to the same data address cannot be performed more than the limited number of times.

Next, the control operation will be explained. Rotary tillage device (
When R) is raised to a predetermined level or higher, the rear cover (15), which is swingably supported by the support shaft (33), comes into contact with the striker (34), as shown in Fig. 4. do,
Swinging in the hanging direction is restricted. This regulating posture is adjusted in advance to stay within a predetermined error when manufacturing the rotary tillage device (R), and the data from the tilling depth sensor (16) in this regulating posture is the reference value (ideal data). As a result, if there is a difference, the value of the difference is written to the EEPROM (24) as a control standard, and if there is no difference, the value of zero is written to the EEPROM (24). Control with small errors can be performed by converting the reference and data from the tillage sensor (16) into values corrected by calculation, and then comparing the data with the data from the tillage depth setting device (14).

The control device (19) includes an EEF ROM (24
), a writing means (A) writes the data to a predetermined data address (a1) of A data address changing means (,C') is provided for sequentially changing the write data address when reaching the address shown in FIG. The writing means (A
), reading means (B) and data address changing means (
C) is provided as a control program in the control device (19), and a control flowchart is shown in FIG.

In the automatic elevating control as described above, the E E P
Read the number of writes to ROM (24) up to the previous time and the data to be stored (Step S, ), E
The memory area of the E P ROM (24) is stored in the write count dedicated address (a2) as the previous write count plus 1 (STEP S2), and the write count is less than 10,000 times. Determine whether or not (
Step S3). If the number of times is less than 10,000, the data is written to a predetermined data address (a1) (step Sa), and automatic elevation control is continued.

If the number of times is 10,000 or more, the area where data should be written is replaced with another unused data address (a3
) (step S4), and reset the write count data to "0" (step Ss). Next, the data to be stored is written to the new data address (a3) (step Ss), and the number of data writes is held in the new write count dedicated address (a4) (step St).

In this way, EEPROM (24) can be used without complicating the structure such as having data stored in static RAM using a backup means such as a capacitor.
Data can be retained only by

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the data holding device according to the present invention, in which FIG. 1 is a control block diagram, FIG. 2 is a control flowchart,
Figure 3 is a diagram showing the address map of non-volatile memory, Figure 4
The figure is a vertical view of the lower limit regulating part of the tilling device, and FIG. 5 is an overall side view of the agricultural tractor. (24)...Nonvolatile memo IJ, (A)...
...Writing means, (B) ...Reading means,
('C)...Data address changing means, (a1
)...Data address.

Claims (1)

[Claims] Nonvolatile memory that can be electrically written and erased (24
), a writing means (A) writes measurement data to a predetermined data address (a_1), a reading means (B) reads the data, and the number of times data is written and erased to the data address (a_1) reaches a predetermined number of times. Then, the data address changing means (
C) A data holding device comprising: