JP2011058921A - Device and method for measuring electrical property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure an electrical property of an AC signal while adopting a total average system. <P>SOLUTION: A device 1 for measuring an electrical property of an AC signal S1 including a processing section 5 for calculating an electrical property of the AC signal S1 updated and displayed at every display updating period T1, based on sampling values D1 for at least one wavelength of the AC signal S1 acquired at every display updating period T1, includes a zero cross detection section 3 for detecting a rising zero cross point on the AC signal S1 and outputting a detection signal S3 to the processing section 5. When the number of the sampling values D1 acquired during an acquisition period starting from a zero cross point corresponding to an initially input detection signal S3 in one display updating period T1 does not reach one wavelength of the AC signal S1 by the end of the one display updating period T1, the processing section 5 prolongs the acquisition period until predetermined conditions are satisfied, with a limit of a predetermined maximum prolongation time. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electrical property measuring apparatus and an electrical property measuring method for measuring electrical properties such as an average value and an effective value of an AC signal.

  As this type of electrical characteristic measuring apparatus, a sampling type measuring apparatus disclosed in Patent Document 1 below is known. This sampling type measuring apparatus includes a digital filter calculation means for performing a digital low-pass filter calculation, a summation average calculation means for summing average processing of sampling data, and a digital filter calculation based on a preset data update cycle (display update cycle). Switching means for switching between the means and the sum average calculating means, and the switching means is configured to switch to the sum average calculating means when the preset data update cycle is less than the time required for the digital filter calculation. Yes.

  Therefore, according to this sampling type measuring apparatus, it is possible to realize measurement with high-speed response and measurement with high accuracy by selecting digital filter calculation or summation average calculation based on the data update period.

Japanese Patent Laying-Open No. 2005-201645 (page 3-4, FIG. 1)

  However, the following problems exist in the electrical characteristic measuring apparatus. In other words, as described above, this electrical characteristic measuring apparatus is configured such that the switching means switches to the total average calculating means when the preset data update cycle is less than the time required for the digital filter calculation. .

  However, as described in the above publication, in the total average calculation method, an accurate measurement result can be obtained unless a signal waveform of one cycle or more is input during the data update cycle (display update cycle). I can't. For this reason, based on the condition that the preset data update period is less than the time required for the digital filter calculation, the above-mentioned electrical characteristic measuring device configured to switch the switching means uniformly to the summation average calculation means, There is a problem to be solved that an accurate measurement result cannot be obtained when a signal waveform of one cycle or more is not input during a data update cycle (display update cycle).

  The present invention has been made in view of such problems, and it is an object of the present invention to provide an electrical characteristic measuring apparatus and an electrical characteristic measuring method that can accurately measure the electrical characteristics of an AC signal while adopting a summation average method. Objective.

  In order to achieve the above object, the electrical characteristic measuring apparatus according to claim 1 is for at least one wavelength of the alternating current signal to be acquired at each display update period, to obtain the electrical characteristic of the alternating current signal to be updated and displayed at each display update period. An apparatus for measuring an AC signal electrical characteristic, comprising a processing unit that calculates based on a sampling value, wherein a zero-cross point of a predetermined type for the AC signal is detected and a detection signal is output to the processing unit. And the processing unit is configured such that the number of sampling values acquired in an acquisition period starting from the zero cross point corresponding to the detection signal input first in one display update cycle is the one display update. If one wavelength of the AC signal is not reached by the end of the cycle, the predetermined upper limit time is set as the maximum extension time until the predetermined condition is satisfied. Extending the acquisition period.

  The electrical property measuring apparatus according to claim 2 is the electrical property measuring apparatus according to claim 1, wherein the processing unit is configured to extend the acquisition time once for each extension time of a predetermined length. Extend the maximum extension time as the extension time.

  The electrical property measuring device according to claim 3 is an electrical property measuring device according to claim 2, further comprising an A / D conversion unit that samples the alternating current signal and outputs the sampling value. Each time the extension is performed once, the sampling rate is lowered with respect to the A / D converter.

  The electrical property measuring apparatus according to claim 4 is the electrical property measuring apparatus according to any one of claims 1 to 3, wherein the processing unit is predetermined to input a new detection signal. As the condition, when the condition is satisfied, the acquisition of the sampling value is stopped to end the acquisition period, and the display unit displays the electrical characteristics based on the acquired sampling value for one wavelength. To display.

  Moreover, the electrical property measuring device according to claim 5 is the electrical property measuring device according to any one of claims 1 to 4, wherein the processing unit is configured such that the length of the acquisition period reaches the upper limit time. The acquisition of the sampling value is stopped to end the acquisition period, and a predetermined warning process is executed.

  In order to achieve the above object, the electrical characteristic measuring method according to claim 6 is for at least one wavelength of the alternating current signal to acquire the electrical characteristic of the alternating current signal to be updated and displayed at each display update period. An electrical characteristic measurement method for calculating based on a sampling value, wherein the acquisition starts from the zero-cross point first detected in one display update cycle while detecting a predetermined type of zero-cross point for the AC signal When the number of sampling values acquired within a period does not reach one wavelength of the AC signal by the end of the one display update cycle, a predetermined upper limit time is set until a predetermined condition is satisfied. The acquisition period is extended as the maximum extension time.

  The electrical property measurement method according to claim 7 is the electrical property measurement method according to claim 6, wherein when the acquisition time is extended, the maximum time for one extension is increased by a predetermined extension time. The extension time will be extended.

  The electrical property measuring method according to claim 8 is the electrical property measuring method according to claim 7, wherein the sampling rate for the sampling value is lowered each time the one-time extension is performed.

  An electrical property measurement method according to claim 9 is the electrical property measurement method according to any one of claims 6 to 8, wherein the predetermined condition is that the new detection signal is input. When the above condition is satisfied, the acquisition of the sampling value is stopped to end the acquisition period, and the electrical characteristic is calculated based on the acquired sampling value for one wavelength and displayed on the display unit.

  An electrical property measurement method according to claim 10 is the electrical property measurement method according to any one of claims 6 to 9, wherein when the length of the acquisition period reaches the upper limit time, the sampling value The acquisition is stopped to end the acquisition period, and a predetermined warning process is executed.

  7. The electrical characteristic measuring apparatus according to claim 1 and the electrical characteristic measuring method according to claim 6, wherein the sampling value is acquired within an acquisition period starting from a zero cross point corresponding to a detection signal first input in one display update period. If the number does not reach one wavelength of the AC signal (one period synchronized with the zero cross point) by the end of this one display update period, a predetermined upper limit time is satisfied until a predetermined condition is satisfied. The acquisition period of the sampling value is extended with the maximum time of extension.

  Therefore, according to this electrical characteristic measuring apparatus and electrical characteristic measuring method, even if the sampling value for the AC signal cannot be acquired for one wavelength during the display update period, the acquisition period is automatically extended. As a result of being able to increase the possibility of obtaining one wavelength of sampling values for the AC signal, it is possible to increase the probability that the electrical characteristics of the AC signal can be accurately measured while adopting the summation average method.

  Further, in the electrical property measuring apparatus according to claim 2 and the electrical property measuring method according to claim 7, when the acquisition period is extended, the maximum time for one extension is increased by a predetermined extension time. Extended as time. Therefore, according to this electrical property measuring apparatus and electrical property measuring method, for example, the acquisition period can be gradually extended by defining the extended time to be a short time that is equal to or shorter than the display update cycle.

  In this case, as in the electrical characteristic measuring apparatus according to claim 3 and the electrical characteristic measuring method according to claim 8, the sampling rate of the sampling value is reduced when the acquisition period is extended in units of extended time. Therefore, the increase rate of the total number of sampling values that increase due to the extension of the acquisition period can be reduced, and the sampling values can be stored with a smaller storage capacity.

  Further, in the electrical characteristic measuring apparatus according to claim 4 and the electrical characteristic measuring method according to claim 9, when a new detection signal is input as a predetermined condition and the condition is satisfied, the sampling value is The acquisition is stopped to end the acquisition period, and electrical characteristics are calculated based on the acquired sampling value for one wavelength and displayed on the display unit. Therefore, according to this electrical characteristic measuring apparatus and electrical characteristic measuring method, while shortening the acquisition period, that is, avoiding a situation where the display update of the electrical characteristics is delayed, the electrical characteristics are measured based on the acquired sampling value for one wavelength. The characteristics can be accurately calculated and displayed.

  Further, in the electrical characteristic measuring device according to claim 5 and the electrical characteristic measuring method according to claim 10, when the length of the acquisition period reaches a predetermined upper limit time, the acquisition of the sampling value is stopped and acquired. While the period is ended, a predetermined warning process (for example, warning display) is executed. Therefore, according to this electrical property measuring apparatus and electrical property measuring method, it is possible to avoid a situation in which the acquisition of sampling values for one cycle cannot be obtained over a long period of time and old electrical properties are continuously displayed on the display unit. Therefore, the reliability of measurement of electrical characteristics can be improved.

1 is a configuration diagram showing a configuration of an electrical characteristic measuring apparatus 1. FIG. 3 is a flowchart for explaining the operation of the electrical characteristic measuring apparatus 1; 3 is a timing chart for explaining the operation of the electrical characteristic measuring apparatus 1; 3 is a timing chart for explaining the operation of the electrical characteristic measuring apparatus 1; 3 is a timing chart for explaining the operation of the electrical characteristic measuring apparatus 1;

  Hereinafter, embodiments of an electrical property measuring apparatus 1 and an electrical property measuring method will be described with reference to the accompanying drawings.

  Initially, the structure of the electrical property measuring apparatus 1 is demonstrated with reference to drawings.

  As shown in FIG. 1, the electrical characteristic measuring apparatus 1 includes an A / D conversion unit 2, a zero cross detection unit 3, a measurement unit 4, a processing unit 5, a storage unit 6, and a display unit 7, and the electrical characteristics of the AC signal S1. (In this example, as an example, the average value Vmean and the effective value Vrms) can be measured.

  The A / D converter 2 inputs the AC signal S1 and samples the AC signal S1 with a sampling clock having a sampling period set by the processing unit 5 (a period sufficiently shorter than the period of the AC signal S1). Thus, the amplitude of the AC signal S1 is converted into digital data (hereinafter also referred to as “sampling value”) D1 and output to the processing unit 5. In this case, the sampling period of the A / D conversion unit 2 is controlled by the control signal S2 output from the processing unit 5.

  As an example, the zero-cross detection unit 3 includes a comparator whose threshold is defined as zero volts, and is one of the predetermined types of zero-crossing points of the rising zero-crossing point and the falling zero-crossing point of the AC signal S1. A point (in this example, a rising zero cross point as an example) is detected, and a detection signal S3, which is a pulse signal as an example, is output to the processing unit 5 in synchronization with the detection timing of the zero cross point.

  The measuring unit 4 is configured by a timer IC or the like, and performs measurement of the display update cycle T1 that is defined in advance each time the trigger signal S5 is input from the processing unit 5, and when the measurement of the display update cycle T1 is completed. The update signal S4, which is a pulse signal, is output to the processing unit 5.

  The processing unit 5 is composed of a CPU or the like, inputs the detection signal S3 and the update signal S4 as interrupt signals, operates according to an operation program stored in the storage unit 6, and performs a summation average operation based on the sampling value D1. The electric characteristic calculation processing 50 (see FIG. 2) for calculating the electric characteristic of the AC signal S1 is executed by the method. The processing unit 5 controls the operation of the A / D conversion unit 2 by outputting the control signal S2, and causes the measurement unit 4 to start the measurement operation by outputting the trigger signal S5.

  The storage unit 6 includes a semiconductor memory such as a ROM and a RAM. The storage unit 6 stores in advance an operation program that defines the operation of the processing unit 5 as described above. Further, the storage unit 6 functions as a work memory of the processing unit 5, and the sampling value D <b> 1 acquired by the processing unit 5 from the A / D conversion unit 2 during the acquisition period, and the electrical characteristics ( The average value Vmean and the effective value Vrms) are stored. The display unit 7 includes a display device such as an LCD (Liquid Crystal Display), and displays the electrical characteristics (average value Vmean and effective value Vrms) calculated by the processing unit 5 and a warning display.

  Next, a method for measuring the electrical characteristics of the AC signal S1 by the electrical characteristics measuring apparatus 1 and an electrical characteristics measuring method will be described with reference to the drawings.

  First, in the electrical characteristic measuring apparatus 1, in the operating state, the A / D conversion unit 2 performs sampling on the AC signal S1 at a sampling period preset by the processing unit 5, and the zero cross detection unit 3 detects the zero cross of the AC signal S1. Perform point detection. Therefore, the sampling value D1 is output from the A / D conversion unit 2 in the sampling period to the processing unit 5, and the detection signal S3 is intermittently output from the zero cross detection unit 3.

  In this state, the processing unit 5 first outputs a trigger signal S5 to the measurement unit 4 to start measurement of the display update period T1. Next, the processing unit 5 waits for the input of the detection signal S3, and starts the electrical characteristic calculation processing 50 shown in FIG.

  In the electrical characteristic calculation process 50, the processing unit 5 first starts acquisition processing of the sampling value D1 output from the A / D conversion unit 2 (step 51). Thereby, the acquisition period about the sampling value D1 is started. The processing unit 5 also starts storing the acquired sampling value D1 in the storage unit 6 together.

  Thereafter, the processing unit 5 executes the acquisition process and the storage process of the sampling value D1, and whether or not a new detection signal S3 is input (step 52) and whether or not the update signal S4 is input (step 53). ) Detection is repeated. At this time, each time the detection unit 5 detects the detection signal S3, the processing unit 5 counts the number of detections of the detection signal S3 until the input of the update signal S4 (the end of the current display update period T1) is detected (step S4). 54).

  When the update signal S4 is input during the execution of the above steps 52 to 54 (that is, when the display update cycle T1 has elapsed), the processing unit 5 ends the execution of each of the steps 52 to 54, and then The number of detections of the detection signal S3 within the acquisition period (the period included in the display update cycle T1 in the acquisition period) for the sampling value D1 up to this point is determined (step 55). As a result of the determination, when the number of detection times of the detection signal S3 is 1 or more (when each display update period T1 in FIG. 3 is the case), the sampling value D1 between the pair of zero cross points for the AC signal S1, that is, The sampling value D1 for one cycle of the AC signal S1 is stored in the storage unit 6 for at least one cycle. For this reason, the processing unit 5 ends the acquisition process of the sampling value D1 (step 56). Thereby, the acquisition period about the sampling value D1 is complete | finished.

  Subsequently, the processing unit 5 calculates the electrical characteristics (the average value Vmean and the effective value Vrms) of the AC signal S1 based on the sampling value D1 stored in the storage unit 6 by the total average calculation method, and stores it. The calculated electrical characteristics are displayed (updated display) instead of the electrical characteristics that have been displayed on the display unit 7 so far (step 58). For example, when the electric characteristic B is calculated as in the second electric characteristic calculation process 50 in FIG. 3, the display content (electric characteristic A in this example) displayed in the previous display update cycle T1 is used. The electrical characteristic B is displayed on the display unit 7. Thereby, the electrical characteristic calculation process 50 is completed. Further, the processing unit 5 outputs a trigger signal S5 to the measurement unit 4 after completion of the electrical characteristic calculation processing 50, thereby starting a new measurement of the display update period T1.

  In this case, the time required for the processing from step 55 to step 58 described above is extremely short as compared with the display update cycle T1 (generally 200 ms to 500 ms) (for example, several tens of minutes of the display update cycle T1). Usually, as shown in FIG. 3, since a plurality of AC signals S1 are input within the acquisition period of the sampling value D1 within the display update period T1, the processing unit 5 By repeatedly executing the processing, the electrical characteristics of the AC signal S1 calculated by the processing unit 5 are displayed on the display unit 7 while being updated at the display update period T1.

  On the other hand, when the result of determination in step 55 is that the number of detection times of the detection signal S3 is less than one (zero) (when each display update cycle T1 in FIG. 4), the processing unit 5 displays the display update cycle. The number of sampling values D1 for the AC signal S1 acquired in the acquisition period within T1 has not yet reached the sampling value D1 (a sampling value D1 for one cycle synchronized with the zero crossing point) between the pair of zero crossing points. It is in.

  For this reason, the processing unit 5 outputs the control signal S2 to the A / D conversion unit 2 to increase the sampling period, thereby reducing the sampling rate (step 59), and then measuring the extension time T2. Is started (step 60). Thereby, the acquisition period is extended with the maximum time of one extension as the extension time T2. The extension time T2 can be defined as an arbitrary time. In this example, the extension time T2 is defined as ½ of the display update period T1.

  Thereafter, the processing unit 5 continues to acquire and store the sampling value D1, detects whether or not the detection signal S3 is input (step 61), and the acquisition period of the sampling value D1 reaches a predetermined upper limit time. Whether or not (step 62) and whether or not the extended time T2 has ended (step 63) are repeatedly executed. The upper limit time of the acquisition period can be defined as an arbitrary time, but in this example, as an example, it is defined as the total time (T1 + T2) of the display update period T1 and the extension time T2. To do.

  In the electrical characteristic measuring apparatus 1, during the measurement process of the extension time T2, the sampling rate D1 during the acquisition period stored in the storage unit 6 is reduced by reducing the sampling rate of the A / D conversion unit 2 as described above. It is possible to reduce the increase rate of the total number. In this case, the cycle of the AC signal S1 when the zero cross point cannot be detected within the display update cycle T1 is longer than the cycle of the normal AC signal S1 during which the zero cross point can be detected within the display update cycle T1. Therefore, even if the sampling rate of the A / D converter 2 is lowered, sampling with sufficient accuracy is possible.

  In addition, during the execution of the above steps 61 to 63 within the extension time T2, the processing unit 5 does not reach the upper limit time of the sampling value D1 and does not receive the detection signal S3. Since the number of sampling values D1 acquired during the acquisition period has not yet reached the sampling value D1 between the pair of zero cross points, the process proceeds to step 59 and the A / D conversion unit 2 is reduced again (step 59), and the measurement process of the extension time T2 is started again (step 60). Accordingly, when the acquisition period of the sampling value D1 does not reach the upper limit time and the detection signal S3 is not input, the processing unit 5 repeatedly executes each of the above steps 61 to 63. As a result, the acquisition period of the sampling value D1 is increased. The maximum time for one extension is automatically extended as an extension time T2.

  When the detection signal S3 is input in step 61 (when one of the predetermined conditions is satisfied) during execution of the above steps 61 to 63 within the extended time T2, the processing unit 5 The number of sampling values D1 for the AC signal S1 stored in the storage unit 6 by each processing of acquisition and storage of the sampling value D1 that is continuing is the sampling value D1 between the pair of zero cross points (synchronized with the zero cross point) The sampling value D1) for one cycle is reached.

  In this case, the processing unit 5 executes the above-described steps 56, 57, and 58 to end the acquisition process for the sampling value D1 (this ends the acquisition period of the sampling value D1), and the storage unit Based on the sampling value D1 stored in 6, the electrical characteristics of the AC signal S1 are calculated and stored in the storage unit 6 by the summation average calculation method, and the calculated electrical characteristics are displayed on the display unit 7 until then. Display (update display) instead of the electrical characteristics. Thereby, the electrical characteristic calculation process 50 is completed. Further, the processing unit 5 outputs a trigger signal S5 to the measurement unit 4 after the completion of the electrical characteristic calculation processing 50, thereby newly starting measurement of the display update cycle T1. Therefore, when the acquisition period of the sampling value D1 is automatically extended with the maximum time of one extension as the extension time T2, the electrical characteristics are updated and displayed on the display unit 7 at a cycle slower than the display update cycle T1. .

  Specifically, with reference to FIG. 4, for the first acquisition period in FIG. 4, the processing unit 5 inputs a new detection signal S3 during the first extended time T2. For this reason, when the detection signal S3 is input, the processing unit 5 exits from the processing loops of the above steps 61 to 63, whereby the acquisition period ends. Next, the electrical characteristic A is calculated by the processing unit 5 based on the sampling value D1 acquired during the acquisition period, and the electrical characteristic A is updated and displayed on the display unit 7. For the second acquisition period in FIG. 4, the first extended time T2 ends without the detection signal S3 being input, and at this time, the acquisition period of the sampling value D1 has reached the upper limit time. Since there is no state, the processing unit 5 executes the measurement process of the second extension time T2, and the processing unit 5 inputs a new detection signal S3 during the second extension time T2. For this reason, when the detection signal S3 is input, the processing unit 5 exits from the processing loops of the above steps 61 to 63, whereby the acquisition period ends. Next, the electrical characteristic B is calculated by the processing unit 5 based on the sampling value D1 acquired during the acquisition period, and the electrical characteristic B is updated and displayed on the display unit 7 instead of the electrical characteristic A.

  On the other hand, when the detection signal S3 is not input during the execution of the above steps 61 to 63 and the acquisition period of the sampling value D1 reaches the upper limit time, the processing unit 5 detects this in step 62 and performs sampling. The acquisition process for the value D1 is terminated (step 64). Thereby, the acquisition period of the sampling value D1 ends. In this case, the number of sampling values D1 for the AC signal S1 stored in the storage unit 6 by each processing of acquisition and storage of the sampling value D1 that the processing unit 5 has continued has not reached one cycle. It is in. Therefore, the processing unit 5 displays a warning display on the display unit 7 without calculating the electrical characteristics (step 65). Thereby, the electrical characteristic calculation process 50 is completed. Further, the processing unit 5 outputs a trigger signal S5 to the measurement unit 4 after the completion of the electrical characteristic calculation processing 50, thereby newly starting measurement of the display update cycle T1. That is, the acquisition period of the sampling value D1 is extended using a predetermined upper limit time (in this example, (T1 + T2) as described above) as the maximum extension time.

  Specifically, with reference to FIG. 5, as an example, like the second acquisition period in FIG. 5, the input of the detection signal S3 with a new acquisition period time within the second extended time T2 When the upper limit time (T1 + T2) is reached before, the processing unit 5 ends the acquisition process at this point, and thus the acquisition period ends. In this case, a warning display is displayed on the display unit 7 instead of the electrical characteristic A after the acquisition period ends.

  As described above, in the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, the sampling value D1 acquired within the acquisition period starting from the zero cross point corresponding to the detection signal S3 input first in one display update period T1. If the number does not reach one wavelength of AC signal S1 (one period synchronized with the zero cross point) by the end of this one display update period T1, a predetermined upper limit is satisfied until a predetermined condition is satisfied. The acquisition period of the sampling value D1 is extended with time as the maximum time for extension.

  Therefore, according to the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, the sampling value D1 for the AC signal S1 cannot be acquired for one wavelength (one period synchronized with the zero cross point) during the display update period T1. However, since the acquisition period is automatically extended, the possibility that the sampling value D1 for the AC signal S1 can be acquired for one wavelength can be increased. As a result, the electric power of the AC signal S1 can be obtained while adopting the summation average method. The probability that the characteristics can be measured accurately can be increased.

  In the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, when the acquisition period is extended, the maximum time for one extension is extended as the extension time T2 by an extension time T2 having a predetermined length. Therefore, according to the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, for example, the acquisition period can be gradually extended by defining the extension time T2 to be a short time equal to or shorter than the display update period T1. In this case, since the sampling rate of the sampling value D1 can be reduced when the acquisition period is extended in units of the extension time T2, the sampling value D1 that increases due to the extension of the acquisition period can be set. The increase rate of the total number can be reduced, and the sampling value D1 can be stored with a smaller storage capacity.

  Moreover, in this electrical property measuring apparatus 1 and electrical property measuring method, the input of a new detection signal S3 is set as a predetermined condition, and when this condition is satisfied, the acquisition of the sampling value D1 is stopped and acquired. The period is terminated, and the electrical characteristics are calculated based on the acquired sampling value D1 for one wavelength and displayed on the display unit 7. Therefore, according to this electrical property measuring apparatus 1 and electrical property measuring method, even when the acquisition period is extended, the electrical property can be accurately calculated and displayed based on the acquired sampling value D1 for one wavelength. Therefore, it is possible to avoid a situation in which the display update of the electrical characteristics is delayed.

  Further, in the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, when the length of the acquisition period reaches a predetermined upper limit time, the acquisition of the sampling value D1 is stopped and the acquisition period is ended. A predetermined warning process (display of warning display on the display unit 7) is executed. Therefore, according to the electrical characteristic measuring apparatus 1 and the electrical characteristic measuring method, the acquisition of the sampling value D1 for one period (one cycle) cannot be obtained over a long time, and the old electrical characteristics are displayed on the display unit 7. Since the situation of being continued can be avoided, the reliability of measurement of electrical characteristics can be improved.

  Although the example in which the acquisition period of the sampling value D1 is extended by a predetermined extension time T2 and the maximum time of one extension is extended as the extension time T2 is described above, the period of the AC signal S1 is changed. If the fluctuation range is known to some extent and it is not necessary to gradually decrease the sampling rate each time the extended time T2 is measured, a configuration is adopted in which the acquisition period of the sampling value D1 is restricted only by the upper limit time. You can also. In the case of reducing the sampling rate in this configuration, for example, a configuration in which the sampling rate in the acquisition period after the end of the display update cycle T1 is reduced can be employed. According to this configuration, since the measurement process of the extension time T2 can be omitted in the electrical characteristic calculation process 50, the load on the processing unit 5 can be reduced.

  If the storage capacity of the storage unit 6 has a sufficient margin, the sampling rate at the display update period T1 is maintained without reducing the sampling rate of the sampling value D1 when the acquisition period is extended. A configuration can also be adopted.

  Further, in the electrical characteristic measuring apparatus 1 described above, the configuration including the A / D conversion unit 2 is adopted, but the A / D conversion unit is not included in the electrical characteristic measuring apparatus, and the A / D is provided outside the electrical characteristic measuring apparatus. A configuration in which the conversion unit is arranged may be employed. In this configuration, the processing unit 5 directly inputs the sampling value D1 of the AC signal S1 from the outside. In this case, the zero-cross detection unit 3 is configured by, for example, a logic circuit, and the zero-cross detection unit 3 By determining the polarity while inputting the sampling value D1, it is configured to detect the zero cross point for the AC signal S1, or the processing unit 5 determines the polarity while inputting the sampling value D1. Thus, it is possible to adopt a configuration in which the zero-cross point for the AC signal S1 is directly detected, that is, a configuration that also functions as the zero-cross detection unit 3.

DESCRIPTION OF SYMBOLS 1 Electrical property measuring device 2 A / D conversion part 3 Zero cross detection part 4 Measurement part 5 Processing part 7 Display part D1 Sampling value S1 AC signal S3 Detection signal S4 Update signal T1 Display update period T2 Extension time

Claims (10)

The electrical characteristics of the AC signal provided with a processing unit that calculates the electrical characteristics of the AC signal to be updated and displayed at each display update cycle based on the sampling value for at least one wavelength of the AC signal acquired at each display update cycle. A measuring device,
A zero-cross detection unit that detects a predetermined type of zero-cross point for the AC signal and outputs a detection signal to the processing unit,
The processing unit is configured such that the number of sampling values acquired within an acquisition period starting from the zero-cross point corresponding to the detection signal that is input first in one display update cycle is the end of the one display update cycle. In addition, when the AC signal does not reach one wavelength, the electrical characteristic measuring device extends the acquisition period by setting a predetermined upper limit time as a maximum extension time until a predetermined condition is satisfied.   The electrical characteristic measuring device according to claim 1, wherein when the acquisition time is extended, the processing unit extends the maximum time of one extension as the extension time by an extension time of a predetermined length. An A / D converter that samples the AC signal and outputs the sampling value;
The electrical characteristic measuring device according to claim 2, wherein the processing unit reduces a sampling rate with respect to the A / D conversion unit each time the extension is performed once.   The processing unit assumes that the input of a new detection signal is the predetermined condition, and when the condition is satisfied, stops the acquisition of the sampling value and ends the acquisition period, and the acquisition The electrical property measuring device according to claim 1, wherein the electrical property is calculated based on the sampling value for the one wavelength and displayed on a display unit.   The processing unit, when the length of the acquisition period reaches the upper limit time, stops acquiring the sampling value to end the acquisition period, and executes a predetermined warning process. To 4. The electrical property measuring device according to any one of 4 to 4. An electrical characteristic measurement method for calculating an electrical characteristic of an AC signal to be updated and displayed at each display update cycle based on a sampling value for at least one wavelength of the AC signal to be acquired at each display update cycle,
While detecting a zero-cross point of a predetermined type for the AC signal,
The number of the sampling values acquired within the acquisition period starting from the zero cross point first detected in one display update cycle does not reach one wavelength of the AC signal by the end of the one display update cycle. In some cases, the acquisition period is extended with a predetermined upper limit time as a maximum extension time until a predetermined condition is satisfied.   The electrical characteristic measurement method according to claim 6, wherein when the acquisition time is extended, the maximum time of one extension is extended as the extension time by an extension time of a predetermined length.   The electrical property measurement method according to claim 7, wherein a sampling rate for the sampling value is lowered each time the one-time extension is performed.   When the predetermined condition is that a new detection signal is input, when the condition is satisfied, the acquisition of the sampling value is stopped to end the acquisition period, and the acquired one wavelength The electrical property measuring method according to claim 6, wherein the electrical property is calculated based on the sampling value and displayed on a display unit.   10. The system according to claim 6, wherein when the length of the acquisition period reaches the upper limit time, the acquisition of the sampling value is stopped to end the acquisition period, and a predetermined warning process is executed. The electrical property measuring method described in 1.

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