JPS62148863A - Electronic watthour meter - Google Patents

Abstract

PURPOSE:To display the frequency division ratio of a frequency dividing circuit and power consumption on the same display circuit selectively by providing a frequency division ratio setting circuit which sets the frequency division ratio and a display switching circuit which reads the set frequency division ratio and displays the frequency division ratio and power consumption on the same display circuit selectively. CONSTITUTION:A display control circuit 21 normally sends out a low-level display command signal H, and the switching circuit 23, therefore, selects a counter value signal K from a counter 6 and a display driving circuit 7 drives the display circuit 8 according to the counter value signal K to display to power consumption. When the frequency division ratio is set by the frequency division ratio setting circuit 9, display selection signals P1 and P2 are outputted to the switching circuit 23, which sends out the counted value K and frequency division ratio S to the display driving circuit 7 selectively on a time-division basis as a signal G. Consequently, the display circuit 8 displays the power consumption and frequency division ratio S on the time-division basis.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in electronic energy meters.

[Conventional technology]

FIG. 3 is a configuration diagram of a conventional electronic watt-hour meter.

This electricity meter consists of a voltage transformer (hereinafter referred to as P and T) 1 which obtains a first voltage signal proportional to the load voltage, and a current transformer (hereinafter referred to as P and T) which obtains a second voltage signal proportional to the consumed current. C
, T) are provided, and the first voltage signal from P and TI and the second voltage signal from C and T2 are respectively applied to a voltage-power multiplier circuit (hereinafter referred to as V/W) 3.
A third N pressure signal proportional to the power consumption is generated and sent to the next power-frequency conversion circuit (hereinafter referred to as W/F) 4. And this W/F
4, the measurement pulse signal is converted into a frequency signal proportional to the power consumption, and the frequency of the measurement pulse signal is divided by a preset frequency division ratio in a frequency dividing circuit 5, and the frequency-divided signal is sent to a counter 6, where it is counted. Ru. Thus, the amount of power consumption is obtained from this count value, and the display drive circuit 7 drives the display circuit 8 according to this count value. As a result, the power consumption port is displayed on the display circuit 8.

By the way, the frequency division ratio in the frequency division circuit 5 is set by a frequency division ratio setting circuit 9 consisting of a digital switch. For example, if the frequency division ratio is 3 digits, the frequency division ratio is 3.
If there are four digits, there are four. Each digital switch 11 is configured to output an 8CD code signal for each digit. Note that this frequency division ratio is a value determined according to the metamorphic ratios of 21-cho 1, C, and T2, and is also referred to as a composite metamorphic ratio constant.

[Problem that the invention seeks to solve]

However, since the frequency division ratio setting circuit 9 has a configuration including a digital switch 11 provided on a substrate 10 as shown in FIG. 4, when setting the frequency division ratio, the variable adjustment shaft 12 of this digital switch 11 is Settings are made by rotating the Therefore, even if you set the division ratio, it is an analog setting, so it is unclear whether it has been set accurately.
Furthermore, if the contact points inside the digital switch 11 are misaligned, it is difficult to set the frequency division ratio with high precision, no matter how accurately it is set.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide an electronic watt-hour meter that is equipped with a frequency division ratio display function and can accurately set the frequency division ratio.

[Means for solving problems]

The present invention provides an electronic watt-hour meter in which a metering pulse signal proportional to power consumption is frequency-divided by a frequency-dividing circuit and then counted to determine the amount of power consumed. A ratio setting circuit and a display switching circuit that reads the frequency division ratio set by this frequency division ratio setting circuit and selectively displays this frequency division ratio and power consumption on the same display circuit. This is an electronic watt-hour meter that aims to achieve this goal.

[Effect]

By providing each of the above means, the present invention allows the display switching circuit to read the frequency division ratio set by the frequency division ratio setting circuit, and selectively assigns the frequency division ratio and power consumption to the same display circuit. Is displayed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an electronic watt-hour meter. Note that the same parts as in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted. Now, this electricity meter is provided with a display switching circuit 20. This display switching circuit 20 has a function of reading the frequency division ratio set by the frequency division ratio setting circuit 9 and selectively displaying this frequency division ratio and power consumption on the same display circuit 8. . The specific configuration includes a display control circuit 21 that sends out a display command signal H that is at a high level for a predetermined period when displaying the frequency division ratio, a display selection signal P1 that receives the display command signal H from the display control circuit 21, A flip-flop 22 outputs a signal P2, and upon receiving display selection signals P1 and P2 from this flip-flop 22, selectively sends a count value signal from a counter 6 and a frequency division ratio signal S to a display drive circuit 7. It is composed of a switching circuit 23. Note that the display control circuit 21 may be configured to include, for example, a push button and send out a high-level display command signal H when the push button is pressed, or may be configured to send out a high-level display command signal H for a predetermined period of time, for example, once a month. Alternatively, a time limit circuit or the like may be provided so as to send out a display command signal H that changes between a high level and a low level at a predetermined cycle at a predetermined time limit in one day.

Next, the operation of the wattmeter configured as described above will be explained. Normally, the display control circuit 21 sends out a low-level display command signal H, so the flip 70 knob 22 outputs a low-level display selection signal P1 from the Q output terminal, and a high-level display selection signal P1 from the d output terminal. A display selection signal P2 is output.

As a result, the switching circuit 23 selects the counter value signal K from the counter 6 and sends it to the display drive circuit 7. In this way, the display drive circuit 7 drives the display circuit 8 according to the count value signal K to display the amount of power consumption.

Now, when the frequency division ratio is set in the frequency division ratio setting circuit 9, or when a predetermined time limit has elapsed, the display control circuit 21 outputs the second
A display command signal H that remains at a high level for a predetermined period as shown in the figure is sent to the flip-flop 22. Then, the flip-flop 22 outputs display selection signals P1 and P2 from the Q output terminal and the Q output terminal to the switching circuit 23, respectively.

Here, as shown in FIG. 2, the high level period of the display command signal H is 6 at times ℃1 to ℃2, t3 to t4, and t5.
..., the display selection signal P1 is from time t1 to ℃2, t
It becomes high level between 3 and t4, t5 and t6,...
On the other hand, the display selection signal P2 is applied at times t2 to t3 and t4.
It is at a high level during ~t5, . . . . Therefore, the switching circuit 23 operates at times t1-t2, t3-t4, t5-t6,
. . . As shown in FIG. 2, the frequency division ratio signal S is selected and sent to the display drive circuit 7.
, . . ., the counter value signal K is selected and sent to the display drive circuit 7.

In this way, the switching circuit 23 sends a signal G in which the count value and the frequency division ratio S are selected in a time-division manner as shown in FIG. 2 to the display drive circuit 7. As a result, the power consumption and the frequency division ratio S are displayed on the display circuit 8 in a time-division manner. Therefore, the frequency division ratio displayed here is monitored and the frequency division ratio is set in the frequency division ratio setting circuit 9 which is composed of a digital switch.

In this way, in the above embodiment, the display switching circuit 20
The frequency division ratio set by the frequency division ratio setting circuit 9 is read by the frequency division ratio setting circuit 9, and the frequency division ratio and the power consumption are selectively displayed on the same display circuit 8, which has not been done in the past. The frequency division ratio can be displayed and the frequency division ratio can be set accurately while monitoring the displayed frequency division ratio. Therefore, even if there is a shift in the contact point inside the digital switch, the division ratio can be set accurately, and the shift in the contact point inside the digital switch can be determined. Electronic watt-hour meters with P, TI, and C, T2 are often used as management instruments in factories, etc., and therefore accurate consumption cannot be achieved unless the frequency division ratio is set accurately. Power loss management becomes impossible. Moreover, since the frequency division ratio in such a power meter is determined by the transformation ratios of P, T1.15 and C, T2, it is necessary to set the frequency division ratio to a reliably determined frequency division ratio. If you use a heavy power meter, the frequency division ratio will be displayed, so you can set the frequency division ratio accurately and manage the power consumption accurately. It can be displayed in time periods such as once a month or once a day, and an accurate frequency division ratio can be set at all times.

Note that the present invention is not limited to the above-mentioned embodiment, and can be modified without departing from the spirit thereof.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide an electronic watt-hour meter that can accurately set the frequency division ratio.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram showing an embodiment of an electronic watt-hour meter according to the present invention, and Fig. 2 is an operation of the watt-hour meter shown in Fig. 1 in the division ratio display operation. A timing diagram, FIG. 3 is a configuration diagram of a conventional electronic watt-hour meter, and FIG. 4 is an external view of a digital switch. 1... P, T, 2... C, T, 3... Voltage-power multiplication circuit, 4... Power-frequency conversion circuit, 5... Frequency dividing circuit, 6... Counter, 7...Display drive circuit, 8
... Display circuit, 9... Frequency division ratio setting circuit, 20...
Display switching circuit, 21... Display control circuit, 22... Flip-flop, 23... Switching circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 t+ t2 t3 t4 ts
tsFigure 2

Claims (1)

[Claims] In an electronic watt-hour meter that creates a metering pulse signal proportional to power consumption, divides the frequency of this metering pulse signal by a frequency divider circuit, and then counts the amount of power consumed, the frequency division ratio in the frequency divider circuit is A division ratio setting circuit that sets the
An electronic system characterized by comprising a display switching circuit that reads the frequency division ratio set by the frequency division ratio setting circuit and selectively displays this frequency division ratio and the power consumption on the same display circuit. Electric energy meter.