JPH1092474A - Programable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the programable controller capable of making the optimum exchange of a battery. SOLUTION: Sampling time for a discharge function and correspondent data for functional values are stored in a data table 15, and the optimum but approximate discharge function is retrieved out of a control circuit 12. After the aforesaid function has been determined, it is so constituted that the remaining usable time corresponding to the aforesaid function of a battery is read out of the data table 15 so as to allow its remaining time data 18 to be indicated. By this constitution, the time used of the battery is computed so as to be indicated, and the optimum exchange time is thereby provided, the occurrence of operational interruption of equipment due to errors made, is thereby prevented, and the remaining usable time of the battery is also grasped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable controller (hereinafter, referred to as a PC), and a function of automatically calculating and displaying a remaining available time of a power supply battery used for backing up user programs and data. The present invention relates to a PC provided with a.

[0002]

2. Description of the Related Art A conventional PC power supply will be described. A general PC includes an input unit, an output unit, a memory unit, a control circuit unit, a peripheral device unit, and a power supply unit that supplies power to these units. The input unit has a function of converting an external signal from a limit switch, a push button switch, or an operation switch into a signal level that can be handled inside the PC. The output unit has a function of converting a signal inside the PC into a level at which a control target such as an electromagnetic switch or an electromagnetic valve can be directly driven. The memory unit stores input signals, output data, and programs. The control circuit unit calculates input data, performs a sequence operation and the like according to a program stored in the memory unit, and controls a peripheral device unit described later. Peripheral unit is PC
And a higher-level computer for writing a program connected to the program. Power supply unit, input unit, output unit,
It supplies electricity to the memory unit, control circuit unit, and peripheral device unit.

[0003] The above-mentioned power supply device has L as an actual target load.
SI, IC, and their supply values are DC5V, 12V, 1
It is various such as 5V, -5V, -9V, -15V. PC
Is made using a logic circuit, and the logic circuit is difficult to recover from a once-occurred mistake, so that the stability of the power supply device has been considered. In particular, when the power is turned off, a battery, for example, a lithium battery or the like is often used as an uninterruptible backup power supply for backing up user programs and data stored in the RAM.

[0004]

With reference to FIG. 9, a description will be given of a conventional decrease in terminal voltage due to battery discharge. FIG. 9 is a discharge characteristic diagram of a terminal voltage of a conventional battery. In FIG. 9, the vertical axis is the terminal voltage of the battery, the horizontal axis is the battery usage time, the bold line 1 is an example of the actual battery discharge characteristic curve, and the thin line 5 is another example of the actual battery discharge characteristic curve. For example, the dotted line 6 is a discharge characteristic curve of the battery under the worst use condition.

[0005] As shown in the figure, when a battery such as the lithium battery is discharged, its terminal voltage is reduced and consumed, and the voltage drops to a voltage V2 (4) at which a backup function cannot be maintained, a user program or data is lost. There is a risk of being stricken. Therefore, when the battery voltage drops to the battery error determination threshold value V1 (2), a battery error signal is generated, a warning is issued to the user, and the user who has received the warning has stopped the equipment.

However, the battery has a standard life at a rated ambient temperature, the degree of wear differs depending on conditions such as ventilation, ambient temperature, and the like, and the discharge characteristic curve of the terminal voltage varies, so that a battery error signal is generated. Black dot 3
Are different in time position. For this reason, the user does not know when the battery error occurs, and suddenly the battery error occurs, so that the unscheduled stoppage of the equipment has been inevitable. Further, since the recommended replacement time tc (7) of the battery is determined based on the discharge characteristic line 6 of the battery terminal voltage under the worst use conditions, the actual value t1 of the battery usage time is determined.
In many cases, the distance from (8) is greatly different, and there is a problem that the customer needs to know the actual value of the battery usable period is large. Furthermore, there is a problem that there is a great need to be able to know the replacement time because the management of the battery replacement time is complicated.

As described above, it has not been known when a battery error will occur, and there has been a danger of unplanned equipment stoppage. Further, the recommended replacement time tc (7) of the battery determined based on the discharge characteristic line of the terminal voltage under the worst use condition.
In accordance with the above, the customer himself manages the replacement time, frequently stops the equipment at a cycle lower than the actual value of the battery usable time,
There is a problem that replacing the battery requires a large economic burden.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, and automatically calculates a remaining usable period of a battery used for backing up user programs and data. An object of the present invention is to provide a PC capable of calculating and displaying an optimum battery replacement time by displaying.

[0009]

The configuration of the programmable controller according to the present invention is characterized in that it comprises means for calculating the remaining usable time of the attached power supply battery. In the programmable controller according to the preceding paragraph, the calculating means includes a storage means for storing data for each predetermined sampling time of each discharge characteristic curve based on a difference in the use condition of the power supply battery, and a sampling time closest to the predetermined discharge time. And selecting means for selecting a discharge characteristic curve in which the difference between the stored terminal voltage at the latest sampling time and the terminal voltage at the predetermined discharge time is the smallest. And calculating the remaining usable time of the power supply battery based on the discharged characteristic curve. In the above-mentioned programmable controller, the sampling time selecting means selects a sampling time such that a difference from the predetermined discharge time is minimized. In the programmable controller according to the preceding paragraph, a season adjustment function is added to the calculation means. In the programmable controller according to the preceding paragraph, a learning function is added to the calculating means. In the programmable controller according to the preceding paragraph, the calculation means is provided with a function of switching between year display, month display, day display, and time display in accordance with the available remaining time. is there.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a PC according to the present invention will be described with reference to FIGS. In the embodiment of the present invention, a battery usable remaining time calculation circuit is added to a conventional PC. Note that, of the basic configuration of the PC, a repetitive description of a portion common to the related art will be omitted because it is complicated, and the description will focus on the characteristic portion.

FIG. 1 shows a PC according to an embodiment of the present invention.
FIG. 3 is a block diagram of the configuration of FIG. In FIG. 1, the terminal voltage of a backup battery 10, for example, a lithium battery is A / A
The data is converted into digital data by the D converter 11 and the control circuit 1
Enter 2 Further, time data is input to the control circuit 12 from the calendar clock 13. The control circuit 12 obtains a characteristic diagram of the discharge reduction of the battery voltage from the digital data of the terminal voltage of the backup battery 10 and the time data. FIG. 2 is a discharge characteristic diagram of a backup lithium battery in the PC of FIG.

Here, in order to operate the PC, it is not necessary to use the backup battery 10, for example, a lithium battery for backup of a user program or the like when the commercial power supply is energized, and the battery voltage waveform 19 when the commercial power supply is energized. Since the battery is not consumed, its terminal voltage is constant, and it is used as a backup when the commercial power is not supplied. Therefore, the battery is consumed, so that only the voltage waveform 20 at that time drops.

Referring to FIG. 3, a method of calculating the usable time of the battery will be described. FIG. 3 is a diagram showing the relationship between the usage time of the backup lithium battery and the terminal voltage. As shown in the figure, a backup lithium battery (hereinafter, referred to as a battery) is used for a cumulative power supply time 24 of the commercial power supply after the start of use.
The battery is not consumed, and the starting voltage V
At 0 (9), the terminal voltage of the battery does not change. During the battery discharge time 25 obtained by subtracting the commercial power supply cumulative time 24 from the total use time 22 of the battery, the terminal voltage of the battery becomes the current terminal voltage Vx (2
1).

During the discharge time 25 of the battery, the terminal voltage drop waveform shows a quadratic function curve. Therefore, the function formula is obtained, and the terminal voltage becomes V2 based on the function formula.
The remaining usable time 17 until (4) is obtained can be calculated. In order to obtain the above function expression, the terminal voltage drop waveform of the battery is approximated by a discharge function (exponential function in the figure) and expressed by the following expression (1).

(Equation 1) In the above equation, V0 is a terminal voltage at the start of use of the battery, and can be changed according to the specification of the battery to be used. K is a coefficient that determines the shape of the discharge waveform.

In the memory 14 shown in FIG. 1, the terminal voltage V0 (9) at the start of use of the battery,
4 and the total battery usage time 22 are stored. Thus, the discharge time 25 is obtained from the difference between the total battery use time 22 and the cumulative power supply time 24 of the commercial power supply. The data table 15 of FIG. 1 includes sampling times of various battery discharge characteristic curves (hereinafter simply referred to as discharge functions) according to several types of use conditions and terminal voltage values of the battery (hereinafter simply referred to as functions) at each sampling time. (Corresponding to a value), and further stores the remaining usable time 17 of the battery under its use condition based on the discharge function at each sampling time, together with the function value. .

The control circuit 12 determines the intersection of the terminal voltage V0 (9) at the start of use of the battery and the cumulative supply time 24 of the commercial power supply, that is, P1 in FIG. 3, the current battery terminal voltage Vx (21) and the discharge time. An exponential function closest to this terminal voltage drop waveform is retrieved from the intersection of 25, that is, P2 in FIG. The approximate discharge function and the sampling time closest to the battery discharge time 25 are determined, and the remaining usable time 17 as a backup battery can be read from the data table 15. The control circuit 12 converts the read remaining battery life 17 into usable remaining time display data 18 such as year, month, day, time, etc., as necessary, and outputs the data to a liquid crystal display.
Transfer to special internal output, etc. This allows the user
The optimal replacement time can be known by checking the remaining usable time of the battery on the liquid crystal display or monitoring the special internal output.

Referring to FIG. 4, an example of calculating the remaining usable time from the present battery terminal voltage Vx (21) after discharging and the discharging time 25 of the battery will be described more specifically. FIG. 4 is an explanatory diagram of an approximation method of the discharge function in the terminal characteristic diagram of the battery of FIG. First, in order to explain the method of approximating the discharge function of the battery, a description will be given using the discharge function of the above-described equation (1). In Equation (1), for simplicity of explanation, the use condition such as ventilation and ambient temperature is changed to make the coefficient K a positive rational number, and this rational number is constant under constant use conditions such as ventilation and ambient temperature. A data table 15 (see FIG. 1) is used as data with function values (voltage values) for each predetermined sampling time for each rational value of the coefficient K.
To be stored. In FIG. 4, each function value (voltage value) at each sampling point is indicated by a black dot. Further, in the discharge function of the predetermined coefficient K, the remaining usable time of the battery based on the use condition is also calculated and stored in advance.

Referring to FIG. 5, a data structure of data table 15 will be described. FIG. 5 is an explanatory diagram of the data structure of the data table in FIG. As shown in the figure, the data in the data table 15 is a function search number indicating a function, a function of 0 in the figure, K = k0 (28), and a sampling time t = t0 indicating a value at a time. (2
It is stored as a function value 33 corresponding to 9). further,
A function value 33 corresponding to each function search number 0, K = ki, i = 0, 1, 2,... (28) and each sampling time t = tj, j = 0, 1, 2,. And the remaining battery available time 3 corresponding to each function search number (28) and each sampling time (29)
4 are stored as a pair.

Next, the process of approximating the discharge function to the terminal voltage drop characteristic of the battery shown in FIG. 4 will be described with reference to FIG. FIG. 6 is a flowchart of the approximation process of the discharge function in the PC of FIG. 1, and FIG. 7 is a flowchart of searching for the sampling time of the approximation process of FIG. First, in step 71, a sampling time t2 (30) closest to the battery discharge time 25 is searched for and determined. Ideally, it is desirable that the battery discharge time 25 and the sampling time t2 (30) match. The selection of the sampling time will be described later in detail with reference to FIG.

Then, in step 72, one is selected from a number of discharge functions Ki. First, i = 0, that is, Ki = K0 is selected. In step 73, the difference between the voltage value Vx (21) of the battery at the discharge time 25 and the voltage value f0 (t2) on the discharge function K0 is determined. If this is expressed by a mathematical expression, R0 = | f0 (t2) -Vx (21) | And i = 0, 1, 2,..., That is, K1, K2, K3, K4.
Is determined, and the difference between the voltage value Vx (21) at the discharge time 25 and the voltage values f1 (t2), f2 (t2),... On the discharge function K1 is determined for the entire discharge function Ki. Next, step 7
This is stored in 4. In step 75,
The stored value is searched, and a discharge function Ki (Ki = k1 in the figure) that minimizes Ri = | fi (t2) -Vx (21) | is selected. In step 76, the remaining available battery time in the discharge function Ki is obtained from the data table 15. In step 77, the data is converted into display data, sent to a display or the like, and displayed.

Referring to FIG. 7, battery discharge time 25
The search for the sampling time t2 (30) that is closest to is described. In step 81, the sampling time t
j, for example, j = 0, that is, t0. In step 82, the difference between the sampling time t0 and the discharge time 25 is calculated. S0 = | t0-discharge time 25 | is calculated. tj
= 1, 2, 3,..., Sj = | tj−discharge time 2
5 | In step 83, tj = 1, 2, 3,...
Are stored as Sj = | tj-discharge time 25 |. In step 84, the stored tj =
Sj = | tj-discharge time 25 for all of 1, 2, 3...
│, the sampling time tj (tj in the figure)
= T2).

In the process of calculating the remaining battery life 17, the operating conditions such as ventilation, ambient temperature, etc. are changed to obtain the coefficient K.
, And a function value (voltage value) for each predetermined sampling time for each integer value of the coefficient K is stored as data in the data table 15 (see FIG. 1), but the coefficient K does not change during the use period. It is a premise. The processing when the coefficient K changes during the use period will be described.

(1) Season Adjustment Function Since the degree of discharge of the battery is particularly affected by the ambient temperature, if the usable remaining time 17 is about several months, the remaining time differs depending on the season. for that reason,
As shown in FIG. 3, it is also possible to calculate the seasonal adjustment discharge function 27 by multiplying the voltage drop prediction discharge function 26 by the seasonal adjustment coefficient, and display the remaining usable time 17 after seasonal adjustment. That is, the discharge function is displaced by changing the radius of curvature with P2 as a transition point. As a specific example of the seasonal adjustment, if the coefficient after the seasonal adjustment is K ′, then K ′ = K × T / T1 in the above equation (1). T is the ambient temperature and T1 is the annual average temperature.

(2) Learning Function With reference to FIG. 8, a description will be given of a method of calculating the remaining battery life by the learning function. FIG. 8 is an explanatory diagram of a method of calculating the remaining battery usable time by the learning function.
The remaining usable time of the battery is calculated assuming the worst case that the commercial power supply of the PC will always remain unpowered in the future. Are often mixed, and in this case, the remaining usable time of the battery is extended. As shown in FIG. 8, based on the time ratio between the energized section 35 and the non-energized section 36 of the past commercial power supply, a predicted energization time ton (37) and a predicted non-energized time toff (38) are obtained. Remaining battery time 40 reflecting the current energized / unenergized ratio
Is calculated. That is, the discharge function is shifted downward (rightward in the figure) from Vx (21). Energizing section 3
If the ratio 5 / the non-energization ratio 36 and the estimated energization time ton (37) / the estimated non-energization time toff (38) are the same, the coefficient K
Is the same as the remaining battery available time 39.

(3) Display of remaining battery usable time will be described. (A) Display on display By using a display with low power consumption, such as a liquid crystal display, the remaining battery life can be displayed even when the PC is not powered. In addition, it is possible to set such that other information is normally displayed and displayed only when the remaining battery available time becomes short. (B) Writing to the special internal output The special internal output which stores various information such as error information and the current time has an I / O for storing the remaining battery available time.
An O number is provided and written in units such as year, month, day, and time. Thus, a sequence for outputting a warning or the like can be formed when the remaining battery time reaches an arbitrary time by using the special internal output storing the remaining battery available time on the user program. (C) Automatic display switching When the remaining battery available time is still large, the year is displayed, but as the time decreases, the display is automatically switched to month display, day display, and time display. In addition, a message such as "It is time to replace the battery" is displayed, and a warning is given by sound.

[0025]

As described above in detail, according to the configuration of the present invention, the remaining usable time of the battery used for the backup of the user program or data is automatically calculated and displayed and displayed to the user. Provides a programmable controller that can provide information on the optimal battery replacement time, thereby preventing unscheduled equipment stoppage due to sudden battery error occurrence, grasping the actual value of battery usable time, and reducing the burden of battery replacement time management. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram of a PC according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a reduction in discharge of a backup lithium battery in the PC of FIG. 1;

FIG. 3 is a diagram showing a relationship between a usage time of a backup lithium battery and a terminal voltage.

FIG. 4 is an explanatory diagram of a method of approximating a discharge function in the terminal characteristic diagram of the battery in FIG. 3;

FIG. 5 is an explanatory diagram of a data structure of a data table in FIG. 1;

FIG. 6 is a flowchart of approximation processing of a discharge function in the PC of FIG. 1;

FIG. 7 is a flowchart for searching the sampling time in the approximation processing of FIG. 6;

FIG. 8 is an explanatory diagram of a method for calculating a remaining battery life by a learning function.

FIG. 9 is a discharge characteristic diagram of a terminal voltage of a conventional battery.

[Explanation of symbols]

1, a battery voltage drop waveform; 2, a battery error determination threshold; 3, a battery error occurrence point; 4, a backup impossible voltage; 5, a battery voltage drop waveform, when use conditions are worse than curve 1; Voltage drop waveform under the worst conditions, 7: recommended replacement time, 8: actual value of battery usage period, 9: battery starting voltage, 10: battery,
11: A / D converter, 12: control circuit, 13: calendar clock, 14: memory, 15: data table, 16: display, 17: remaining battery available time, 18: remaining time display data, 19 ... Battery voltage waveform when energized, 20 ...
Battery voltage waveform when power is not supplied, 21: current battery voltage, 22: battery usage time, 23: function value, 24 ...
Cumulative energization time, 25 discharge time, 26 predicted voltage drop waveform, 27 predicted season adjustment waveform, 28 function search number, 2
9: sampling time, 30: sampling time closest to discharge time, 31: approximate discharge function, 32: function value closest to current battery voltage, 33: function search number and function value corresponding to each sampling time, 34: remaining battery usable time corresponding to each function search number and each sampling time, 35: energized section, 36: non-energized section, 37 ...
Estimated energization time, 38: Estimated non-energization time, 39: Remaining battery time obtained by discharge function, 40: Remaining battery time in consideration of the energized / unenergized ratio

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04L 29/00 H04L 13/00 T

Claims (6)

[Claims] 1. A programmable controller, comprising: means for calculating a remaining available time of a mounted power supply battery. 2. The programmable controller according to claim 1, wherein said calculating means stores data for each predetermined sampling time for each discharge characteristic curve based on a difference in use condition of said power supply battery; Selecting means for selecting the latest sampling time of the discharge time; and selecting a discharge characteristic curve in which the difference between the terminal voltage of the stored data for the latest sampling time and the terminal voltage for the predetermined discharge time is minimum. A programmable controller, comprising: selecting means for calculating a remaining usable time of the power supply battery based on the selected discharge characteristic curve. 3. The programmable controller according to claim 2, wherein said sampling time selecting means selects a sampling time such that a difference from said predetermined discharge time is minimized. controller. 4. The programmable controller according to claim 1, wherein a season adjustment function is added to said calculation means. 5. The programmable controller according to claim 1, wherein a learning function is added to said calculating means. 6. The programmable controller according to claim 1, wherein the calculating means is provided with a function of switching one of a year display, a month display, a day display and a time display in accordance with the usable remaining time. A programmable controller, characterized in that: