JPH07225264A - Electronic watt-hour meter - Google Patents

Abstract

PURPOSE:To provide an electronic watt-hour meter in which the time when a battery is used in an electricity-saving mode is computed, in which the total consumed capacity of the battery is computed and which can generate a warning so as to prevent the capacity of the battery from running out. CONSTITUTION:The time just before entering an electricity-saving mode is stored as the time just before an electricity-saving operation (Steps 350). After the electricity-saving mode has been released by a release processing operation, a time clocking operation is started by a clocking means. When the present time is set by the clocking means, the time which has been clocked by the clocking means just before a setting processing operation is stored as the time just before the setting processing operation. The set time by the setting processing operation is stored as the time just after the setting processing operation (Steps 230, 280). On the basis of the time just before the electricity-saving operation, the time just before the setting processing operation and the time just after the setting processing operation, the electricity-saving time when the electricity-saving mode is executed is computed (Steps 250, 300). On the basis of the electricity-saving time and the service-interruption time which is measured by the clocking means in a service-interruption mode, the consumed capacity of a battery is computed. On the basis of the computed consumed capacity of the battery, a warning indicating that the capacity of the battery has been reduced is generated (Steps 270, 320).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic watt-hour meter for measuring and displaying the amount of electric power used from a commercial AC power source, and more particularly, to hold the measured amount of electric power used by a battery even during a power failure. The present invention relates to an electronic power meter that can be displayed.

[0002]

2. Description of the Related Art As shown in FIG. 3, an electronic watt hour meter of this type includes a control unit having a microprocessor (hereinafter abbreviated as MPU) 1. The MPU 1 includes a power source unit 5 and a battery 6, a setting unit 8 and a weighing value display LC via a metering pulse input terminal 2, an AC sync signal converter 3, a power failure detector 4, and diodes 71 and 72, respectively.
D10 ₁ , 10 ₂ ... 10 _n , status display LCD 1
1, a clock display LCD 12 and a crystal oscillator 9 are connected. The MPU 1 has a built-in clock for measuring the time.

The metering pulse input terminal 2 MPUs the metering pulse having a frequency proportional to the electric power, which is the result of multiplying the AC voltage input to the electronic watt-hour meter by the AC current.
1 is input, and the MPU 1 measures the amount of electric power used by the input measurement pulse. The AC sync signal conversion unit 3 outputs a signal synchronized with the frequency of the AC voltage input to the electronic watt hour meter, and outputs the MPU.
Supply to 1. The power failure detection unit 4 is a unit that detects the presence or absence of the AC voltage input to the electronic watt-hour meter, that is, whether the power supply state or the power failure state. The power failure state detected by the power failure detection unit 4 is supplied to the MPU 1. It

The power supply unit 5 forms a DC voltage for operating the MPU 1 from the AC voltage input to the electronic watt-hour meter, and supplies this DC voltage to the MPU 1 via the diode 71. The battery 6 is used for the power supply unit 5 when the AC input power supply fails.
The DC voltage is supplied to the MPU 1 instead of the DC voltage from the power supply unit 5 and the battery 6, and the diode 7
1, 72 are switched and separated.

The setting unit 8 is a unit for setting the time of the clock built in the MPU 1. Crystal unit 9 is MPU
It is used to generate one system clock and also to create the reference frequency of the clock during a power failure.

LCDs for displaying measured values 10 ₁ , 10 _2, ...
10 _n is for displaying the count value obtained by counting the measurement pulses input from the measurement pulse input terminal 2 by the MPU 1 as the measurement value of the electric energy of the electronic watt-hour meter. A plurality of power consumptions are provided so that the corresponding power consumptions can be displayed. The status display LCD 11 displays the input status of the electronic watt-hour meter such as the frequency of the load of the electric power metered by the electronic watt-hour meter, no metering, and power failure. Further, the clock display LCD 12 displays the time of day on the clock by the year, month,
It is designed to display in days, hours, and minutes.

FIG. 4 is a flow chart showing the processing of the conventional electronic watt-hour meter shown in FIG. 3 described above. The process of the electronic watt hour meter shown in FIG. 4 is roughly divided into a metering mode process (step 430) and a power failure mode process (step 4).
40) and 3 of the power saving mode process (step 470)
Have one process.

In the metering mode process, the MPU 1 is supplied with an operating voltage from the power supply unit 5 and is output from the power failure detection unit 4 when an AC voltage is input to the electronic watt-hour meter, that is, when the electronic power meter is in an energized state. A signal indicating that it is in the energized state is input, and the weighing mode process is executed thereby.

In the measurement mode process, the following control process is executed. (1) The MPU 1 counts the metering pulses input from the metering pulse input terminal 2, measures the amount of electric power used, and displays the measured amount of electric power used for each time period on the LCD for displaying the measured value.
10 _1, and displays the 10 ₂ · · · 10 _n, and displays the frequency of the metering pulse input to the state display LCD 11. (2) The MPU 1 has the built-in timepiece as described above, but receives the signal output in synchronization with the AC voltage input to the electronic watt-hour meter from the AC synchronization signal conversion unit 3, and uses this synchronization signal as the basis. The clock is operated as a frequency, and the time of this clock is displayed on the clock display LCD 12. (3) The MPU 1 is designed to receive the signal from the setting unit 8. However, by operating the setting unit 8, M
The time of the clock built in the PU 1 can be set and changed, and after the setting and change, the set and changed contents are displayed on the clock display LCD 12.

In the power failure mode process, the MPU 1 is operated by being supplied with the DC voltage from the battery 6 when the AC voltage is not input to the electronic watt-hour meter, that is, when the power failure occurs. A signal indicating that a power failure state is input from is input from, and the power failure mode process is executed thereby.

In this power failure mode process, the following control process is executed. (1) The MPU 1 prohibits acceptance of the measurement pulse from the measurement pulse input terminal 2. (2) The MPU ₁ displays the weighing amount weighed in the weighing mode process on the weighing value display LCDs 10 ₁ , 10 _2, ... 10 _n . However, since the MPU 1 prohibits acceptance of the measurement pulse from the measurement pulse input terminal 2, the measurement value display LCDs 10 ₁ , 10 _2, ... 10 _n do not make a leap. (3) The MPU 1 displays on the status display LCD 11 that there is a power failure. (4) The clock incorporated in the MPU 1 advances the timekeeping by using the signal oscillated by the crystal oscillator 9 as the basic frequency, and displays the measured time on the clock display LCD 12. (5) The MPU 1 receives a signal from the setting unit 8 and operates the setting unit 8 to set and change the clock included in the MPU 1. After the setting and the change, the set and changed contents are displayed on the clock. Is displayed on the LCD 12 for use.

The power saving mode process is executed when the power failure state continues for a specified time, or when the specified time elapses after the setting unit 8 is operated during the power failure. In this power saving mode process, in order to reduce the consumption of the battery 6 that supplies the operating power to the MPU 1, the MPU 1 is stopped (HAL
T), and the processing of MPU1 is only held in the internal memory. Further, the operation of the crystal unit 9 is stopped, and the weighing value display LCDs 10 ₁ , 10 _2, ... 10 _n , the status display LCD 11, and the clock display LCD 12 are turned off. Further, due to the stop of the crystal oscillator 9, the basic frequency of the timepiece built in the MPU 1 is not supplied to the MPU 1, and thus the timepiece is stopped and reset to the initial state.

The power saving mode process is performed when the AC voltage is input, that is, when the power is restored, or the setting unit 8
When is operated, it is canceled and the process shifts to the weighing mode process or the power failure mode process.

In the electronic watt-hour meter in which the power saving mode process is canceled, the clock is reset to the initial state when the power saving mode process is executed. Therefore, the setting unit 8 is operated to set the correct time, This restarts the operation of the electronic watt hour meter.

[0015]

In the above-mentioned conventional electronic watt-hour meter, in the power failure mode, the clock of the MPU 1 is operating, so the total power failure time is calculated and the current consumption at the time of the power failure determines the power failure. Although it is possible to calculate the consumed capacity of the battery 6 in the power saving mode, since the clock of the MPU 1 stops in the power saving mode, the consumed capacity of the battery 6 in the power saving mode cannot be calculated.

Therefore, it is not possible to calculate the total consumed capacity of the battery 6 in the power failure mode and the power saving mode, and as a result, it is impossible to identify how much the battery 6 has been consumed. There is a possibility that the electronic watt-hour meter will be operated when the alarm cannot be issued and the battery capacity is exhausted. When the electronic watt-hour meter loses power in this way when the battery capacity is exhausted, the operating voltage is not supplied from the battery to the MPU1, which causes all the measured values stored in the internal memory of the MPU1 to be lost. There is a problem that the amount of electric power used becomes unknown because it is reset to the initial state.

The present invention has been made in view of the above,
The purpose is to calculate the time the battery is used in the power saving mode and calculate the total consumed capacity of the battery,
An object is to provide an electronic watt-hour meter capable of issuing an alarm so as to prevent the battery from running out of capacity.

[0018]

To achieve the above object, the electronic watt-hour meter of the present invention has clock means for measuring the time, measures the amount of electric power used from an AC commercial power source, and measures this. A metering mode for accumulating and displaying the amount of electric power, a power failure mode having a function of holding and displaying the accumulated amount of electric power by a battery and measuring the power outage time by the clock means during a power failure of an AC commercial power source, and An electronic type having a power saving mode in which the display of the electric energy and the operation of the clock means are stopped at least when the power failure mode continues for a predetermined time or more, the clock means is reset, and only the electric energy is held by the battery. A watt-hour meter, which stores the time immediately before entering the power saving mode from the clock means as the time immediately before the power saving, and a cancellation process including cancellation of the power failure. After the power saving mode is canceled, the clock means starts time counting by the clock means, and after the power saving mode is canceled by a cancellation process including cancellation of power failure, the current time is set in the clock means. In doing so, before and after the setting process, the time measured by the clock means is stored as a time immediately before the setting, and the time before and after the setting that stores the time set by the setting process as a time immediately after the setting, and immediately before the power saving. Power saving time calculating means for calculating a power saving time during which the power saving mode is executed based on time, the time immediately before the setting, and the time immediately after the setting, and the power saving time calculated by the power saving time calculating means and the power saving mode A battery consumption capacity calculation means for calculating the consumption capacity of the battery based on the power failure time measured by the clock means; And summarized in that having an alarm means for generating an alarm indicating the in based on the consumption capacity of the calculated battery the capacity of the battery is reduced.

[0019]

In the electronic watt-hour meter of the present invention, the time immediately before entering the power saving mode is stored as the time immediately before the power saving, and after the power saving mode is canceled by the canceling process, the time counting is started by the clock means, When setting the current time in the clock means, the time measured by the clock means until immediately before the setting processing is stored as the time immediately before setting, and the time set by this setting processing is stored as the time immediately after setting, and immediately before the power saving. Time, calculate the power saving time during which the power saving mode is being executed based on the time immediately before setting and the time immediately after setting, and calculate the battery consumption capacity based on the power saving time and the power failure time measured by the clock means in the power failure mode, An alarm indicating that the battery capacity has decreased is generated based on the calculated battery consumption capacity.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a control unit used in an electronic watt hour meter according to an embodiment of the present invention. The control unit of the electronic watt-hour meter shown in the same figure has a battery capacity dead alarm unit 13 added to the control unit of the conventional electronic watt-hour meter shown in FIG. 3 described above, and the MPU 1 will be described later. The only difference is that the processing shown in FIG. 2 is performed, and the other configurations are the same. Therefore, in the configuration of FIG. 1, the same components as those of FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 2 is a flow chart showing the operation of the embodiment shown in FIG. Before sequentially explaining the processing shown in FIG. 2, an outline of the processing shown in FIG. 2 will be described. The processing shown in FIG. 2 is roughly divided into weighing mode processing 1 (step 230), weighing mode processing 2 (step 270), power failure mode processing 1 (step 280), and power failure mode processing 2.
(Step 320), power saving mode processing (Step 36)
0).

In addition to performing the same processing as the weighing mode processing shown in FIG. 4, the weighing mode processing 1 sets the time of the clock incorporated in the MPU 1 when the time is set or changed. And the current time B of the clock before being changed is stored in the internal memory of the MPU 1, and the time after the time of the clock is changed, that is, the change time C, is stored in the MPU 1.
1 is stored in the internal memory.

In the weighing mode process 2, the consumed capacity of the battery 6 is calculated, the calculated consumed capacity is compared with the capacity of the battery,
When the battery capacity is reduced to near the capacity exhaustion, the battery capacity exhaustion alarm unit 13 outputs an alarm.

In the power failure mode process 1, in addition to performing the same process as the power failure mode process shown in FIG. 4, when the time of the clock incorporated in the MPU 1 is set or changed, the time of the clock is set. And the current time B of the clock before being changed is stored in the internal memory of the MPU 1, and the time after the time of the clock is changed, that is, the change time C, is stored in the MPU 1.
1 is stored in the internal memory.

In the power failure mode process 2, the power failure mode time is calculated, the battery consumption capacity in the calculated power failure mode time is calculated, and the calculated capacity consumption is compared with the battery capacity. When the battery capacity is almost exhausted, the battery capacity exhaustion alarm unit 13 outputs an alarm.

The power saving mode process is the same as the power saving mode process shown in FIG. Further, in the processing of this embodiment shown in FIG. 2, the condition for entering the power saving mode is satisfied, and the condition for entering the power saving mode is satisfied immediately before the processing enters the power saving mode, that is, in the power failure state. Immediately before the processing enters the power saving mode, the current time A is set to MPU1.
The power saving mode flag n indicating the power saving mode is set to "1" at the same time as being stored in the internal memory of the CPU (steps 330 to 350).

The condition for this processing to enter the power saving mode processing is that the setting section 8 is set when the state in which the power failure mode processing 1 and 2 is executed continues for a prescribed time or while the power failure mode processing 1 and 2 is being executed. When operated, after the operation,
This is the case where the prescribed time continues, and in this case, it is determined that the condition for entering the power saving mode process is satisfied, and the power saving mode process is entered.

During execution of the power saving mode processing, MP
U1 is in a stopped state (HALT state), and the clock of MPU1 is reset to the initial state and stopped. The power saving mode process is canceled when an AC voltage is input to the electronic watt-hour meter, that is, when the power failure is canceled and power is restored, and when the setting unit 8 is operated.

Next, the processing shown in FIG. 2 will be sequentially described with reference to the flow chart while taking the above conditions into consideration. Figure 2
In the process (1), the system is first initialized (step 210). In this initialization, each interrupt flag is reset, the memory is initialized, and so on. When the initialization is completed, it is checked whether or not there is a power failure (step 22).
0).

If there is no power failure, the routine proceeds to step 230, where the weighing mode process 1 is executed. In the weighing mode process 1, as described above, the weighing pulses input from the weighing pulse input terminal 2 are counted to calculate the weighing value of the electric energy, and the weighing value display LCDs 10 ₁ , 10 _2, ... 10 _n
Is displayed.

When the measurement mode process 1 is completed,
It is checked whether or not the power saving mode flag n is 1 and the time has been changed in the weighing mode process 1 (step 240).

If the power saving mode flag n is not 1 and the time is not changed, the process proceeds to step 270 and the weighing mode process 2 is performed. In this weighing mode process 2,
Although the consumed capacity of the battery 6 is calculated and a process for outputting an alarm is performed, in the current state, the power saving mode flag n = 0 and the power saving mode process has not yet been performed. The process is not performed, and the process returns to step 220 to check again whether or not there is a power failure.

In the power failure check in step 220, if it is detected by the power failure detection signal from the power failure detection unit 4 that the power failure is detected, the process proceeds to step 280 and the power failure mode process 1 is executed. In this power failure mode process 1, the MPU 1 operates with the DC power of the battery 6, prohibits acceptance of the measurement pulse, displays the measurement value and the power failure, and displays the power from the crystal unit 9 as described above. The clock of the MPU 1 continues to operate with the basic frequency, and the time during which the power failure mode process 1 continues due to the operation of this clock, that is, the power failure time is measured.

When the power failure mode process 1 is completed, it is checked whether the power saving mode flag n is 1 and the time has been changed (step 290). When the power saving mode flag n is not 1 and the time is not changed, the process proceeds to step 320 and the power failure mode process 2 is performed. In this power failure mode processing 2, the power failure mode time measured in the power failure mode processing 1 of step 280 is calculated,
The consumed capacity of the battery 6 is calculated based on the calculated power failure mode time and the consumed current in the power failure mode process, and the consumed capacity and the capacity of the battery 6 are compared. An alarm is output. The current consumption in the power failure mode process is a known value that is measured at the time of manufacturing the electronic watt hour meter.

When the power failure mode process 2 is completed, it is checked again based on the output signal from the power failure detection unit 4 whether or not there is a power failure (step 330). If it is not a power failure, the process returns to step 230 and the weighing mode process 1 is executed again, but if it is still a power failure, it is checked whether the conditions for entering the power saving mode process are satisfied (step 340). ).

As described above, the condition for entering the power saving mode process is that the power outage mode process 1 (step 280) and the power outage mode process 2 (step 320) are executed for a prescribed time, or the power outage mode process is executed. 1 and 2
This is the case where the specified time continues after the setting unit 8 is operated during execution of. If the condition for entering the power saving mode process is not satisfied, the process returns to step 280 to execute the power failure mode process 1 again, but if the condition for entering the power saving mode process is satisfied. Is step 3
In step 50, the current time, that is, the current time A immediately before entering the power saving mode process is stored, and the power saving mode flag n is set to 1.

Then, the power saving mode process is executed (step 360). In this power saving mode process, the MPU 1 is set to a dormant state (HALT state) in order to reduce the consumption of the battery 6, and the process of the MPU 1 is only to hold the internal memory. Further, the operation of the crystal unit 9 is stopped, the timepiece is reset to the initial state and stopped, and the weighing value display LCDs 10 ₁ , 10 _2, ... 10 _n are turned off.

After the power saving mode process, it is checked whether or not the power is restored, that is, whether or not the power failure is released (step 370). If power is restored, step 23
Returning to 0, the weighing mode process 1 is executed again, but if the power is not restored, it is checked whether or not the setting unit 8 has been operated (step 380). If the setting unit 8 is not operated, the process returns to step 360 and the power saving mode process is repeatedly executed. If the setting unit 8 is operated, the process returns to step 280 and the power failure mode process 1 is executed. Will be implemented again.

As described above, the power saving mode flag n
Is set to 1 and the power saving mode process is executed, then the power is restored (step 370), and when the measurement mode process 1 is entered, the process described above is performed in the measurement mode process 1. When the time of the clock is changed by the setting unit 8 during execution of the weighing mode process 1, the current time B before the time change of the clock and the change time C after the time change of the clock are stored in the internal memory of the MPU 1. Memorized and displayed again. In this case, the current time B before the time change of the clock indicates the time from the power recovery to the time change of the clock. This is because, when the power saving mode process was entered, the timepiece was reset and stopped, but the timepiece starts operating at the same time as the power is restored.

Then, following the weighing mode process 1, it is checked in step 240 whether the power saving mode flag n is 1 and the time has been changed. In the current state, the power saving mode flag n is 1, and the time has also been changed as described above. Therefore, the processing proceeds to step 250, and the processing for calculating the power saving mode processing time is performed. In this power saving mode processing time calculation processing, as described above, in step 35.
From the current time A immediately before entering the power saving mode process stored in 0, the current time B before the time change stored in the weighing mode process 1 and the changed time C after the time change, the power saving mode process is executed by the following equation. The time D that has been spent is calculated.

[0041]

## EQU1 ## D = C-B-A When this power saving mode processing time D is calculated, step 2
In step 60, the power saving mode flag n is reset to 0, and then in the weighing mode process 2 (step 270), the battery 6
The cumulative value AH of the consumed capacity of is calculated by the following equation.

[0042]

[Mathematical formula-see original document] AH = AH + (D * i _s ) In this equation, i _s is a current consumption at the time of executing the power saving mode process, which is measured and known at the time of manufacturing the electronic watt hour meter.

Then, the accumulated value AH of the consumed capacity of the battery 6 calculated in this way is compared with the capacity of the battery 6, and as a result of this comparison, when it is found that the battery 6 is almost out of capacity. Will output an alarm from the battery capacity exhaustion alarm unit 13.

On the other hand, as described above, after the power saving mode flag n is set to 1 and the power saving mode process is executed, the power is not restored yet, but the setting unit 8 is operated to execute the power saving mode process. If is canceled (Step 3
80), power failure mode process 1 is executed (step 28)
0). The above-described processing is performed in this power failure mode processing 1, but if the time of the clock is changed by the setting unit 8 during execution of this power failure mode processing 1, the current time B before the time change of the clock and the clock are performed. Change time C after changing the time
Is stored in the internal memory of MPU 1 and is displayed again.
In this case, the current time B before the time change of the clock indicates the time from the cancellation of the power saving mode process to the time change of the clock. This is because, when the power saving mode process was started, the timepiece was reset and stopped, but the timepiece starts to operate at the same time when the power saving mode process is released.

Then, following the power failure mode process 1, it is checked in step 290 whether the power saving mode flag n is 1 and the time has been changed. In the current state, the power saving mode flag n is 1, and the time has also been changed as described above. Therefore, the processing proceeds to step 300, and the processing for calculating the power saving mode processing time is performed. In this power saving mode processing time calculation processing, similar to step 250 described above, the current time A immediately before entering the power saving mode processing, the current time B before the time change stored in the power failure mode processing 1, and the time after the time change From the change time C, the time D during which the power saving mode process is executed is calculated by the following equation.

[0046]

## EQU00003 ## D = C-B-A When this power saving mode processing time D is calculated, step 3
At 10, the power saving mode flag n is reset to 0, and then, in the power failure mode process 2 (step 320), the execution time T _t of the power failure mode process from the power failure mode process 1 to the power failure mode process 2 is calculated, and the battery 6 is consumed. The cumulative value AH of the capacity is calculated by the following equation.

[0047]

In Equation 4] AH = AH + (D × i s) + (T t × i t) This equation, i _s is the current consumption during the execution of the power saving mode processing, i _t is a power failure mode processing 1 It is a current consumption at the time of execution, and both current consumptions are known and measured at the time of manufacturing the electronic watt hour meter.

Then, the accumulated value AH of the consumed capacity of the battery 6 thus calculated is compared with the capacity of the battery 6, and as a result of this comparison, when it is found that the battery 6 is almost out of capacity. Will output an alarm from the battery capacity exhaustion alarm unit 13.

[0049]

As described above, according to the present invention,
Calculates the power-saving time during which the power-saving mode is executed based on the time immediately before the power-saving mode, the time immediately before the time setting process, the time immediately before the time setting process, and the time immediately after the time setting immediately after the time setting,
Since the battery consumption capacity is calculated based on the power saving time and the power failure time measured by the clock means in the power failure mode, an alarm indicating that the battery capacity has decreased is generated based on the calculated battery consumption capacity. , It is possible to prevent the battery from running out of capacity, and it is possible to eliminate the problem that the amount of power used in the battery that was used in the past disappears due to running out of battery capacity. A high electronic watt-hour meter can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control unit used in an electronic watt hour meter according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment shown in FIG.

FIG. 3 is a block diagram showing a configuration of a control unit of a conventional electronic watt-hour meter.

FIG. 4 is a flowchart showing an operation of a control unit of the conventional electronic watt-hour meter shown in FIG.

[Explanation of symbols]

1 MPU 2 Metering pulse input terminal 4 Power failure detection section 5 Power supply section 6 Battery 8 Setting section 9 Crystal oscillator 10 ₁ , 10 ₂・ ・ ・ 10 _n LCD for displaying measured value 12 LCD for clock display 13 Battery capacity alarm section

Claims (1)

[Claims] 1. A metering mode having a clock means for measuring time, measuring the amount of electric power used from an AC commercial power source and accumulating and displaying the measured amount of electric power, and by a battery during a power failure of the AC commercial power source. A power failure mode having a function of holding and displaying the accumulated power amount and measuring a power failure time by the clock means, and displaying the power amount and the clock means when at least the power failure mode continues for a predetermined time or more. Is an electronic watt-hour meter having a power saving mode in which the battery is stopped, the clock means is reset, and only the amount of power is retained by the battery, and the time immediately before entering the power saving mode is the time immediately before the power saving. Time saving means immediately before power saving stored by the clock means, and clocking of time by the clock means after the power saving mode is released by a release process including release of power failure A timer starting means for starting, after said power-saving mode by the release process including cancellation of power outage is canceled, per To set the current time to the clock means,
A time before / after setting means for storing the time measured by the clock means just before the setting processing as a time immediately before the setting, and a time set immediately after the setting as a time immediately after the setting; A power-saving time calculating means for calculating a power-saving time during which the power-saving mode is executed based on the immediately preceding time and the time immediately after the setting; and the clock means for measuring the power-saving time calculated by the power-saving time calculating means and the power failure mode. A battery consumption capacity calculating means for calculating the battery consumption capacity based on the power outage time, and an alarm indicating that the battery capacity has decreased based on the battery consumption capacity calculated by the battery consumption capacity calculating means An electronic watt-hour meter, comprising: