JP4946711B2 - Data storage method and data display method - Google Patents

Description

The present invention relates to a method for storing long data, and a method of displaying it.

  Recent AC servo systems require enhanced maintenance functions. For example, when a servo amplifier protection function is activated, an error occurs by displaying motor operation data such as the previous motor speed or torque command. It is necessary to have the function of analyzing the cause of the problem and shortening the lead time of countermeasures.

  However, since there are generally a plurality of protection functions, the required data is different, and the time constant of each data is, for example, data in which a change of several ms is important, for example, and there is data that changes only in the order of a few s.

  When trying to measure these data at a fixed sampling period, if the sampling period is increased to the order of several s, the operation data of the order of several ms is missed, and conversely the sampling period is on the order of several ms. In order to avoid overlooking operation data on the order of several s, a large amount of storage area is required for the servo amplifier.

  Also, when trying to download and display data inside the servo amplifier from an application on the PC such as software that supports the setup of the servo amplifier, it takes a very long time to transfer a large amount of operation data. When the communication speed is slow, it is often not practical.

As a solution to this technical problem, there is a trend data display device. As shown in FIG. 4, a level 0 short cycle data memory that stores the original signal on the data storage device side, and a level 1 to level 5 long cycle data memory from which feature values are extracted step by step, Further, by storing the association between levels represented by dotted lines, the data display device first presents long-period data that can be viewed over the whole, and stores the short-period data at a specific time point for which details are desired to be stored. Are sequentially displayed (see, for example, Patent Document 1).
JP 2004-30599 A

  However, this is one of the conventional technical problems, which is effective for shortening the transfer time between the data storage device and the display device, but there is an extra storage area for storing long-period data and association information. Therefore, there is a problem that the storage area required on the data storage device side increases.

The present invention is made to solve the conventional problems, not the method of storing the measurement data sampled every period as in the prior art without any loss, by reducing the serial憶容amount
A data storage method which can store data of long time, and to provide a display method for displaying it.

In order to solve the above-mentioned problem, a data storage method according to claim 1 of the present invention provides measurement data having a cycle T0 of cycles 2 ^k · T0, 2 ^(k−1) · T0,. . . , 21 · T0, 20 · T0 (k is an integer equal to or greater than 1), and distributed and stored in a plurality of different storage areas.

In the data storage method according to claim 2, the storage area is 2 ⁿ for the longest period 2 ^k · T0 and 2 ⁽ⁿ⁻¹⁾ for the other periods (n is an integer of 1 or more ^). ), Which uses a ring buffer.

In the data storage method according to claim 3, when the size of the entire storage area is 2 (n + m), k = 2 · (2 ^m −1) (n and m are integers of 1 or more). To do.

Furthermore, the data display method according to claim 4 displays the 2n pieces of data having the longest period of 2 ^k · T0 stored by the data storage method according to any one of claims 1 to 3 as they are. For shorter periods, 2 ^(n-1) stored data and 2 ^(n-1) latter half of the data with twice the period are alternately superimposed to display ²ⁿ data, Is repeated until the display of the period T0, so that ²ⁿ pieces of data are displayed for each period.

According to the data storage method of the first aspect of the present invention, data such as motor operation over a long period of time is stored by storing data immediately before the occurrence in a short cycle and storing data at a longer time in a long cycle. It is possible to effectively increase the storage capacity and to suppress an increase in storage capacity by using a ring buffer and avoiding data duplication of these multiple periods.

Further, according to the data storage method according to claim 2, dating back to the past time point Ru Ah starting, can be measured at a plurality of sampling periods as the period for each power of two is increased, the same as more same number of data Ki out to save the number of motor operation data, as the sampling period is shortened number data close to the time that is currently measuring the same for resolution is high, the number of data long sampling period as the measurement time is extensive same for It becomes coarse and the resolution is low and can be measured.

According to the data storage method of the third aspect, a combination that makes the most effective use of the storage area can be obtained.

Further, according to the display method of the fourth aspect, ²ⁿ data that is twice the data of the storage area can be restored for each period. In addition, since the number of data is the same for each period, the accuracy of the data does not change even if waveforms with different periods are switched and displayed.

Measured data of period T0 is represented by periods 2 ^k · T0, 2 ^(k−1) · T0,. . . , 21 · T0, 20 · T0 (k is an integer of 1 or more), 2n for the longest period of 2k · T0, 2 ^(n-1) for other periods (n is an integer of 1 or more ⁾ The data storage device distributes and stores the data in a ring buffer having a size of 2). The longest 2k data of 2 ^k · T0 stored in the data storage device is displayed as it is. The stored 2 ^(n-1) data and the second half data ^{(2-1) of the} double cycle are alternately overlapped to display ²ⁿ data, and this is repeated until the display of the cycle T0. Thus, the data display method is characterized in that ²ⁿ data is displayed for each period. Embodiments will be described below.
(Embodiment 1)
FIG. 1 is an explanatory diagram of an operation concept of the data storage device and the data display device according to the first embodiment, FIG. 2 is a flowchart of a data storage destination ring buffer selection process, and FIG. 3 is a display data creation process flowchart.

  In FIG. 1, the original signal for each T0 with the shortest period is shown at the top, and these 32 pieces of data are respectively used in periods 8T0, 4T0, 2T0, and T0 (when k in claim 1 is 3). Store in the corresponding level 3 to level 0 ring buffer.

The ring buffer has four data records at level 3 (when n is 2 in claim 2), and two data records from level 2 to level 0.

  Which ring buffer to store data for every cycle T0 is determined by the flowchart shown in FIG. 2 for each cycle T0 so that the data does not overlap.

  In FIG. 2, in step 1, the measurement start time is set to 0, and a count value that increases every period T0 is associated with the original signal data. In step 2 to step 4, the least significant bit when the count value is expressed in binary is set to bit 0, and the smallest n in which bit n is 1 is found. In step 5, the original signal data is stored in the level n ring buffer. If bit 0 to bit k (k is the maximum level value, here 3) are all 0, in step 6, data is stored in level k.

  When data is stored using the algorithm shown in FIG. 2, since the ring buffer is used in the storage area, old data with a short period disappears. As a result of giving up the past detailed data, 32 original data are given. The storage area necessary for storing the signal data can be reduced to ten.

  Next, the data display device will be described. The data display device sequentially reads the storage data of the data storage device and restores the display data. This restoration process can be realized by the algorithm shown in the flowchart of FIG.

  First, in step 1 to step 2, the longest stored data of level k is read and stored as display data of level k as it is (the number of data is 2n).

Next, in step 3 to step 5, the storage data of level k-1 (the number of data is 2 ^(n-1) ) is read, and the latter half of the display data of level k created previously (the number of data is 2 ^{(n -1)} pieces) are alternately arranged to create display data of level k-1. By continuing the steps 3 to 5 until the display data of level 0 is created, the display data of all the levels of 2 ⁿ data can be restored.

  In order to show the effect of the data storage device and the display device, the necessary storage capacity (Table 1), the measurement time with the longest period (Table 2), and the ratio thereof (Table 3) are changed while changing n and k. The calculated results are shown in the table. In all the tables, the column of k = 0 indicates a case where the period T0 is fixed.

The storage capacity in Table 1 increases as the number of stages k increases, but the amount of data that overlaps between levels also increases, so the overall storage capacity increase rate is 3/2, 4/3, 5/4,. . . Decreases as k increases. Here, n corresponds to the number of data 2n displayed in each cycle.

  In Table 1, the upper part divided by the underline shows the combination of k and n that has a storage capacity equal to or less than the case where k = 0 (fixed period T0) and n = 8 (256 storage areas). Show.

  When the period T0 is fixed, only 256 data and one data with the period T0 can be measured. However, by setting the number of data in each period to 128, which is half, k = 2 can be obtained, and three data of periods 4T0, 2T0, and T0 can be measured simultaneously.

  Further, when the number of data is reduced to 64, which is half, k = 6 can be obtained, and seven data of 64T0, 32T0, 16T0, 8T0, 4T0, 2T0, and T0 can be measured simultaneously.

In general, considering the case where the storage capacity is 2 ^{(n + m)} , it can be derived that k = 2 · (2 ^m −1) can be obtained when the number of data in each period is 2 ⁿ .

  Also, paying attention to the measurement time with the longest period in Table 2, the measurement time increases on the order of 2k with respect to the increase in k. Therefore, the longer the measurement is possible, the larger k is compared to the increase rate of the storage capacity. It becomes.

  In order to make this clearer, the ratio of the storage capacity and the measurement time is calculated and displayed in Table 3. When the period T0 is fixed, only one period of data can always be measured per storage capacity. Increasing this ratio increases geometrically.

  Specifically, when numerical values are applied, when the storage capacity is 256 with a period of 1 ms, since the ratio is 1 when the period is fixed, only one data for a period of 256 ms can be obtained. However, when k = 2, the ratio is doubled and the number of data is 128, but three types of data of 128 ms (cycle T0), 256 ms (cycle 2T0), and 512 ms (cycle 4T0) are obtained.

  Further, if k = 6, the ratio is greatly increased to 16 times, and the number of data is 64, and 64 ms (period T0) and 128 ms (period 2T0), 256 ms (period 4T0), 512 ms (period 8T0) and 1 Seven types of data, .024s (cycle 16T0), 2.048s (cycle 32T0), and 4.096s (cycle 64T0) are obtained, and the measurement time with the longest period is certainly 16 times the measurement time with the fixed period. It has become.

  Although it is not in the table, if the data amount is further reduced to 32, which is half, k = 14, the ratio will be 2048 times, so about 9 minutes, 16 will be k = 30, the ratio will be 67108864 times, about 200 days A wide range of data can be recorded.

  As described above, the data storage device and the data display device according to the present invention can dramatically increase the ratio of the measurement time to the storage area with respect to the fixed-cycle data measurement by measuring the data near the trigger with a shorter cycle. Can do.

  For this reason, it is not possible to know when it occurs, such as when the servo system protection function is activated, but it is possible to record events that require data display over a wide period from a short period to a long period. It is suitable when you want to realize with.

In the first embodiment, since the storage area size is emphasized, the number of data is specified by a power of 2. However, the same effect can be obtained even if an integer of 3 or more is used as a radix.

  Further, if it is desired to obtain data having the shortest period longer than the measurement having the longest period, the effect of this patent is not greatly reduced even if the remaining storage area is allocated to each period.

The data storage method and the data display method of the present invention can be used for measuring an event in which a time scale measured by a control parameter changes, such as measurement of positioning settling time in a position control servo, measurement of rise / fall time with respect to a speed command, This is very useful because it is not necessary to repeat the measurement while changing the sampling period.

Claims (4)

Period T ₀ The measurement data sampled every time is converted into the period T ₀ Step 1 for associating with the count value incremented every time and clearing the variable i to 0,
Step 2 for determining whether the variable i is the maximum level k (k is an integer of 1 or more);
Step 3 for determining that the i-th bit of the counter value is 1 when the determination result of Step 2 is false;
Step 4 in which the variable i is incremented and the process proceeds to Step 2 when the determination result in Step 3 is false;
When the determination result in step 3 is true, step 5 stores the current measurement data in the i-th ring buffer;
When the determination result of step 2 is true, the step consists of step 6 of storing the current measurement data in the k-th ring buffer.
Data storage method. The kth ring buffer is 2 ⁿ , Other k-1 to 0th ring buffers are 2 ^(N-1) 2. The data storage method according to claim 1, wherein a ring buffer having a size of n (n is an integer of 1 or more) is used. 3. The data according to claim 2, wherein when the total size of the storage area is 2 ^{(n + m)} , k = 2 · (2 ^m −1) (n and m are integers of 1 or more). Memory method . A step 1 of setting (k + 1) ring buffer data stored in the data storage method according to any one of claims 1 to 3 to a variable i with a maximum level k;
Step 2 for copying ⁿ pieces of i-th stored data 2 to i-th display data;
Step 3 for decrementing variable i;
Step 4 for determining whether the variable i is greater than or equal to 0 and terminating the process if false,
If the determination in step 4 is true, the i-th stored data 2 ^(n-1) and the i + 1-th display data half 2 ^(n-1) are alternately arranged in order from the largest count value. Step 5 to generate 2 ⁿ pieces of i-th display data ,
A data display method consisting of: