JP2017116480A - Watthour meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a watthour meter capable of improving convenience.SOLUTION: A microcomputer 11 of a watthour causes a memory 16 to store time acquired from a clock IC 15 as cut-off time when a power supply cut-off state is detected, and acquires the cut-off time from the memory 16 when a power supply recovery state is detected. The microcomputer 11 acquires time acquired from the clock IC 15 as recovery time when the power supply recovery state is detected. The microcomputer 11 calculates and adds a difference between the recovery time and the cut-off time as stop time of measurement target equipment.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a watt-hour meter that monitors power consumption of a device to be measured.

  2. Description of the Related Art Conventionally, for example, in buildings and factories, watt hour meters are provided in each facility (measurement target device) in order to monitor power consumption in electrical facilities (see, for example, Patent Document 1).

JP 2011-59072 A

  By the way, in the watt-hour meter as described above, for example, it is conceivable to measure the operation time and stop time of the measurement target device in order to notify the user of the operation rate of the measurement target device. However, if the watt-hour meter and the measurement target device are operating on the same power system, the power meter cannot measure the stop time of the measurement target device if a power failure occurs in the power system. Can be considered. That is, there is room for improvement in terms of convenience.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a watt-hour meter capable of improving convenience.

  A watt-hour meter that solves the above problems includes a power measurement unit that measures the power consumption of a measurement target device, and a stop time measurement that measures a time during which the power consumption of the measurement target device is not measured in the power measurement unit as a stop time And a shutdown detection unit that is connected to the same system as the power supply unit that supplies power to the measurement target device and detects a power shutdown state in which power supply from the power supply unit is stopped, and returns from the power shutdown state A return detection unit for detecting the power recovery state, and a time acquired from the clock IC when the power shutdown state is detected by the shutdown detection unit, and stored in the nonvolatile memory as a cutoff time, and the return detection unit When the power recovery state is detected, the shutdown time acquisition unit that acquires the cutoff time from the nonvolatile memory when the power recovery state is detected, and when the power recovery state is detected by the recovery detection unit A return time acquisition unit that acquires a time acquired from the clock IC as a return time; and a calculation unit that calculates a difference between the return time and the shut-off time. The difference between the calculated cutoff time and the return time is added as the stop time of the measurement target device.

  According to this configuration, the difference between the recovery time when the power recovery status is detected from the power shutdown status due to a power failure and the shutdown time when the power shutdown status due to a power failure is detected, that is, the power failure time is measured. This is the equipment stop time. For this reason, even when the watt hour meter is not operating due to a power failure, the power failure time can be used as the stop time of the measurement target device. The improvement can be aimed at.

In the watt-hour meter, it is preferable that after the return time is acquired by the return time acquisition unit, the cutoff time is acquired from the nonvolatile memory by the cutoff time acquisition unit.
According to this configuration, the return time acquisition unit acquires the return time before the cutoff time acquisition unit acquires the cutoff time stored in the memory, and the return time acquisition unit acquires it from the clock IC. The time difference from the actual return timing can be suppressed.

  The watt-hour meter includes an auxiliary power source for driving the shut-off time acquisition unit for a first predetermined time when the power shut-off state is detected by the power status detection unit, and the shut-off time acquiring unit Preferably, the time is acquired from the timepiece IC every second predetermined time shorter than the first predetermined time.

  According to this configuration, the time is acquired every second predetermined time shorter than the first predetermined time by driving the cutoff time acquisition unit for the first predetermined time in the auxiliary power supply after the power-off state. It becomes possible to acquire the time of the power-off state by the cutoff time acquisition unit within the first predetermined time.

  According to the watt-hour meter of the present invention, it is possible to improve convenience.

The block diagram of the watt-hour meter in one Embodiment. The sequence diagram for demonstrating the operation example of the watt-hour meter same as the above.

Hereinafter, an embodiment of the watt-hour meter will be described.
As shown in FIG. 1, the watt-hour meter 10 of the present embodiment measures the power consumption (hereinafter simply referred to as power amount) of the measurement target device 1 that is fed from the power source PS via the power line Lp. is there. In addition, the watt-hour meter 10 measures the operation time and the stop time in addition to the power amount of the measurement target device 1.

The watt-hour meter 10 includes a microcomputer 11, a measurement unit 12, a power supply circuit 13, a power supply cutoff detection circuit 14, a clock IC 15, and a nonvolatile memory 16.
The measurement unit 12 as a power measurement unit includes a voltage input unit 12a and a current input unit 12b.

  The voltage input unit 12a steps down an AC voltage (input voltage) applied from the power source PS to the measurement target device 1 via the power line Lp to a predetermined level and outputs the voltage to the microcomputer 11. The current input unit 12b detects an alternating current (input current) flowing through the power supply line Lp with a current sensor (not shown), converts the secondary current of the current transformer into a voltage signal, and outputs the voltage signal to the microcomputer 11. Since such voltage input unit 12a and current input unit 12b are well known in the art, illustration and description of the detailed configuration are omitted.

  The power supply circuit 13 is connected to the same power supply system as the power supply PS of the measurement target device 1 and converts an AC voltage supplied from the power supply PS into a DC voltage to create an operating power supply for each unit such as the microcomputer 11.

  The power shutoff detection circuit 14 is connected to the power supply circuit 13, and a signal indicating that the power supply has been shut down when the operating power generated by the power supply circuit 13 is shut off is displayed when the power is restored. A signal is output to the microcomputer 11.

The clock IC 15 is a so-called real-time clock, and is configured so as to continue to record the current date and time information and to output the information to the microcomputer 11.
The microcomputer 11 includes a CPU, a memory, an A / D converter, and the like, and by executing a program stored in the memory by the CPU, an input voltage received from the voltage input unit 12a and an input current received from the current input unit 12b. Based on the above, an electric energy calculation process for calculating the electric energy of the measurement target device 1, a measurement (counting) process of the operation time and the stop time of the measurement target device 1, and the like are performed.

  Moreover, the microcomputer 11 adds the time (power failure time) of the power-off state in which power supply is interrupted due to a power failure or the like to the watt-hour meter 10 as the stop time of the measurement target device 1 connected to the same power source PS. It is like that.

When the microcomputer 11 returns from the power shut-off state, the microcomputer 11 can detect the return state by starting power supply to the microcomputer 11 via the power supply circuit 13.
Further, the microcomputer 11 includes a sub battery SB as an auxiliary power supply unit.

The sub-battery SB is, for example, a capacitor, and is for driving the microcomputer 11 for the first predetermined time T1 in a power-off state due to a power failure or the like.
The operation (one operation example) of the watt-hour meter 10 configured as described above will be described.

  The microcomputer 11 of the watt-hour meter 10 of this embodiment calculates the electric energy of the measuring object apparatus 1 from the input current and input voltage which are obtained via the voltage input part 12a and the current input part 12b. Further, the microcomputer 11 uses the timepiece IC 15 to measure the time when the input current is obtained from the current input unit 12b as the driving time and the time when the input current is not obtained from the current input unit 12b as the stop time.

  As shown in FIG. 2, the microcomputer 11 acquires the current time from the timepiece IC 15 every second predetermined time T2. In the present embodiment, the second predetermined time T2 is set shorter than the first predetermined time T1 for driving the microcomputer 11 after the power is shut off by the sub battery SB.

  As shown in FIG. 2, when a power interruption (power failure) occurs at a certain timing, the power interruption detection circuit 14 notifies the microcomputer 11 of a signal indicating that the power is cut off. The microcomputer 11 obtains the current time from the clock IC 15 at least once during driving by the sub-battery SB because the first predetermined time> the second predetermined time T2, so that the time is stored in the memory 16 as the cutoff time. To do.

  Thereafter, when the power is restored at a certain timing, the microcomputer 11 obtains the current time from the clock IC 15. Thereafter, the microcomputer 11 acquires the time (shut-off time) stored in the memory 16. In addition, since the microcomputer 11 performs various initialization processes after the power is restored, time is taken in acquiring the time (shut-off time) stored in the memory 16 and acquiring the current time from the clock IC 15 after the power is restored. It will be necessary. For this reason, it is significant to acquire the current time (return time) from the clock IC 15 before acquiring the cutoff time from the memory 16.

Thereafter, the microcomputer 11 calculates the difference between the return time and the cutoff time, and counts (adds) the stop time.
Next, the effect of this embodiment will be described.

  (1) The difference between the return time when a power return state is detected from a power cut-off state due to a power failure or the like, that is, the power-off time when a power cut-off state is detected due to a power failure or the like, Stop time. For this reason, even when the watt-hour meter 10 is not operating due to a power failure, the power failure time can be set as the stop time of the measurement target device 1, so that the measurement of the stop time of the measurement target device 1 becomes possible. Improvements can be made in terms of convenience.

  (2) Since the operation of the microcomputer 11 is stopped after the power is cut off due to a power failure or the like, various initialization processes occur in the microcomputer 11 even when the power is restored. For this reason, it takes time to acquire the time stored in the memory 16 and to acquire the current time from the clock IC 15 after the power is restored. For this reason, the acquisition of the current time from the clock IC 15 is performed before the time stored in the memory 16 is acquired, so that an error in acquiring the current time when the power is restored can be suppressed.

  (3) The time is acquired every second predetermined time T2 shorter than the first predetermined time T1 by driving the microcomputer 11 for the first predetermined time T1 by the sub battery SB as the auxiliary power supply unit after the power is cut off. Therefore, it becomes possible for the microcomputer 11 to acquire the time of power-off state (shut-off time) within the first predetermined time T1.

In addition, you may change the said embodiment as follows.
In the above embodiment, the microcomputer 11 acquires the time from the timepiece IC 15 every second predetermined time T2 shorter than the first predetermined time T1, but the present invention is not limited to this. The first predetermined time T1 and the second predetermined time T2 may be set to the same setting, or the second predetermined time T2 may be set to be longer than the first predetermined time T1.

  -About the acquisition timing of the interruption | blocking time by the microcomputer 11, you may implement based on the detection of a power supply interruption | blocking state. That is, the microcomputer 11 may adopt a configuration in which the time of the clock IC 15 is acquired in response to the detection of the power cutoff state and stored in the memory 16 as the cutoff time.

  -You may combine the said embodiment and each modification suitably.

  DESCRIPTION OF SYMBOLS 10 ... Electricity meter, 11 ... Microcomputer (calculation part, stop time measurement part, return detection part, cutoff time acquisition part, and return time acquisition part), 12 ... Measurement part (power measurement part), 14 ... Power supply interruption detection circuit ( (Blocking detection unit), 15 ... clock IC, 16 ... memory (non-volatile memory), PS ... power supply, SB ... sub-battery (auxiliary power supply unit), T1 ... first predetermined time, T2 ... second predetermined time, 1 ... measurement Target equipment.

Claims (3)

For a power measurement unit that measures power consumption of a measurement target device, a stop time measurement unit that measures a time during which the power consumption of the measurement target device is not measured in the power measurement unit as a stop time, and the measurement target device An interruption detection unit that is connected to the same system as an electric power supply unit that supplies electric power and detects an electric power interruption state in which electric power supply from the electric power supply unit is stopped, and a return detection unit that detects an electric power supply restoration state that has returned from the electric power interruption state And when the power-off state is detected by the shut-off detection unit, the time acquired from the clock IC is stored in the non-volatile memory as the shut-off time, and when the power-return state is detected by the return detection unit A cutoff time acquisition unit that acquires the cutoff time from the nonvolatile memory, and a time acquired from the timepiece IC when the power recovery state is detected by the return detection unit Has a return time acquisition unit that acquires a return time, and a calculator for calculating the difference between the cut-off time and the return time,
The said stop time measurement part adds the difference of the said interruption | blocking time calculated by the said calculating part, and the said return time as a stop time of the said measuring object apparatus, The watt hour meter characterized by the above-mentioned. The watt-hour meter according to claim 1,
The watt-hour meter, wherein after the return time is acquired by the return time acquisition unit, the cutoff time is acquired from the nonvolatile memory by the cutoff time acquisition unit. The watt-hour meter according to claim 1 or 2,
An auxiliary power source for driving the shut-off time acquisition unit for a first predetermined time when a power shut-off state is detected by the shut-off detector;
The watt-hour meter characterized in that the shut-off time acquisition unit acquires time from the timepiece IC every second predetermined time shorter than the first predetermined time.

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