JPH0765282A - Electronic measuring instrument - Google Patents

Abstract

PURPOSE:To output a pulse train which differs in pulse quantity and pulse interval through slight software processing by providing a serial output means which outputs the serial pulse train. CONSTITUTION:A microcomputer 1 sets the bit rate and output bit quantity of the serial output means 2. Then voltage X current = electric power is calculated from the inputs to a voltage input means 3 and a current input means 4. Further, electric energy in one cycle of a totalization period is totalized and the number of pulses (parallel digital value) corresponding to the electric energy is calculated according to a predetermined constant. An output data converting means 5 reads the pulse train pattern (serial output data) corresponding to the calculated number of pulses out of a table in a read-only memory 6 and an output data setting means 7 sets the serial output data for the serial output means 2. Consequently, the pulse train which differs in pulse quantity and pulse interval can be outputted through the slight software processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses measured data to
The present invention relates to an improvement of an electronic measuring instrument having a function of outputting to a remote management office as a serial pulse train in which the number of pulses and the pulse interval are not constant.

[0002]

2. Description of the Related Art Today, with the remarkable progress of semiconductor technology,
A large number of electronic measuring instruments having a means for remotely measuring various physical quantities such as an electric energy meter and sending them to an office for centralized management have been put into practical use.

A microcomputer is usually incorporated in such an electronic measuring instrument, and a pulse train proportional to the measured input physical quantity is output, a pulse train is output by the arithmetic processing of the microcomputer, or a combination thereof is used. It is configured to output a pulse train.

In outputting these pulse trains in the related art, whether the output port of the microcomputer is controlled by software processing to output the pulse train,
The timer output port of the microcomputer is controlled by the timer to output the pulse train.

[0005]

When outputting a pulse train by controlling the output port of the microcomputer by software processing, pulse output control to the output port,
A large load is applied to software processing for pulse width control and pulse interval control, and it is not easy to manage the pulse width and pulse interval.

Further, when a timer output port of a microcomputer is controlled by a timer to output a pulse train, if the number of pulses and the pulse interval of the output pulse train are constant, the software processing is hardly burdened. However, if the number of pulses in the output pulse train or the pulse interval is not constant, it is necessary to frequently control the timer by software processing.In addition, the software processing must be performed while the timer is performing pulse output control. For example, when you want to control the timer due to, it is necessary to adjust the timer control timing by software processing so that there are no missing pulses or insufficient pulse width.
As in the case where the output port of the microcomputer is controlled to output the pulse train, the software processing is greatly burdened.

An object of the present invention is to solve the above-mentioned problems and to provide an electronic measuring instrument capable of realizing the output of a pulse train having a different number of pulses and a different pulse interval by a small amount of software processing.

[0008]

According to the present invention, output data conversion means for converting a parallel digital value into a corresponding pulse train pattern, serial output means for outputting a serial pulse train, and the pulse train pattern set in the serial output means. And an output data setting means for performing the same.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An output pulse from a serial output means, which is usually built in a microcomputer as a serial output port or externally attached as a parallel-serial conversion means, has a time width determined by a bit rate in the case of a synchronous system. The number determined by the number of output bits is arbitrarily output as high or low by software processing. Further, the output from the serial output means can be continuously output in plural units with the output bit number as a unit.

Therefore, an arbitrary pulse train in which the time width determined by the bit rate is set as the resolution and the number of output bits is set as a unit from the serial output means which is built in the microcomputer or is externally attached by an IC or the like. Can be output by software processing of a microcomputer.

Therefore, the bit rate is set so that the output pulse width is N times the time width determined by the bit rate (N is a positive integer), and the pulse train pattern data obtained by software processing is output from the serial output means. By outputting it, it becomes possible to output an arbitrary pulse train in which the number of pulses and the pulse interval are not constant with a slight load of software processing.

FIG. 1 is a block diagram of an electronic watt-hour meter which is an embodiment of the present invention, and FIG. 2 is a flowchart of software processing of the microcomputer 1 in FIG.

The microcomputer 1 initializes the serial output means 2 in steps, and sets the bit rate and the number of output bits of the serial output means 2.

Next, the voltage input to the voltage input means 3 in the step is read, the current input to the current input means 4 in the step is read, and the voltage of the voltage input means 3 read in the step and the step Then, the current input to the current input means 4 is multiplied to calculate voltage × current = power.

Further, the microcomputer 1 totals the electric energy for one cycle of the totaling period (usually a short time such as 500 μS) in step, and the number of pulses corresponding to the electric energy according to a predetermined constant ( Calculate parallel digital values). By this processing, the number of pulses in the counting period is obtained. This pulse number changes depending on the amount of electric power during the aggregation period, and is an integer such as 0 to 8 (here, the fractional part after the decimal point is retained and the error is added by adding it to the aggregated value in the next aggregation period. Lost).

Output data conversion means 5 functionally built in the microcomputer 1 by step data conversion.
The pulse train pattern (serial output data) corresponding to the number of pulses calculated from the table of the read-only memory 6 is read by the serial output means 2 by the output data setting means 7 functionally incorporated in the microcomputer 1 in step. Set the serial output data to. As described above, a serial output pulse train is transmitted from the serial output means 2.

As an example, when the number of pulses of 0 to 8 is output in accordance with the amount of electric power in one cycle of the counting period, 0 is output.
The pulse train pattern in the case of outputting the number of pulses of 8 to 16 bits serially as positive pulses is as shown in FIG.

Normally, the serial output means 2 of the microcomputer 1 has a double buffer structure, and the data of the output bit number set in the initial setting of the step is set to 1
It is a parallel-serial converter that outputs pulses at regular intervals, bit by bit, also at the bit rate set in the initial setting.

To use this function in software,
Except for the initial setting, "the number of bits of serial output data ÷
It is only necessary to set the necessary data in the serial output means 2 by the number of output bits (it is optimal to determine the number of bits of serial output data to an integer multiple of the number of output bits).

That is, when the pulse train data corresponding to the number of pulses corresponding to the electric energy during the totaling period are arranged in the output order and set in the serial output means 2, the number of output bits is 8 and the number of bits of serial output data is 16. Then, since the serial output means 2 normally outputs from the low-order bit, the serial output data set in the serial output means 2 when the number of pulses is "1" is "100000000."
"0000000" is divided into 8-bit units and arranged in the output order, resulting in "0000001" and "00000000", and the setting is required twice.

The bit rate of the serial output data in this case is the number of bits of the serial output data / the time of one cycle of the totaling period (BITS / S).

On the other hand, in order to realize this function by software processing as in the conventional case, an interrupt at a constant interval (corresponding to the above-mentioned bit rate) such as a timer is used, and 1 or 0 is set at each timing. Must be output to the output port, and this must be repeated the number of times corresponding to the number of bits of the output data (16 times in the above example). Although the processing contents in each case are not the same, the software processing can be remarkably reduced even in a simple comparison of the number of times of processing, and according to the present invention, the output of a pulse train in which the number of pulses or the pulse interval is not constant is output. It can be performed without a heavy software processing load.

Further, since the serial output means 2 normally has a double buffer structure, the restrictions on the timing for setting the serial output data in the serial output means 2 by software processing are alleviated considerably.

[0024]

As described above, according to the present invention,
Output data conversion means for converting a parallel digital value into a corresponding pulse train pattern, serial output means for outputting a serial pulse train, and output data setting means for setting the pulse train pattern in the serial output means are provided. Output of pulse trains having different numbers and pulse intervals can be realized by a small amount of software processing.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic watthour meter that is an embodiment of the present invention.

FIG. 2 is a flowchart of software processing of the microcomputer shown in FIG.

FIG. 3 is a diagram showing an example of pulse train data and pulse train patterns of serial output data.

[Explanation of symbols]

 1 Microcomputer 2 Serial Output Means 3 Voltage Input Means 4 Current Input Means 5 Output Data Converting Means 6 Read Only Memory 7 Output Data Setting Means

Claims (1)

[Claims] 1. An electronic measuring instrument having an arithmetic means for outputting a measured value as a parallel digital value, wherein an output data conversion means for converting the parallel digital value into a corresponding pulse train pattern and a serial pulse train are outputted. And an output data setting unit for setting the pulse train pattern to the serial output unit.