JP3203953B2 - Speed measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed measuring device, and more particularly to a speed measuring device used for controlling various physical quantities such as temperature, pressure or flow rate. The improvement of the speed measuring device.

[0002]

2. Description of the Related Art As a control device used for controlling these various physical quantities, a deviation between a target value SV and a measured value PV is used as a control device.
There is well known a configuration in which an operation amount MV is output by performing an ID calculation or the like, and feedback control is performed so that a measured value PV from a control target matches a target value SV. Recently, a control device for performing fuzzy control has also been proposed. In this configuration, the amount of change in the control output is calculated by a fuzzy set operation with respect to the deviation between the target value SV and the measured value PV and the change speed of the deviation. If the target value SV is constant, the deviation of the deviation is calculated. The rate of change can be translated into the rate of change of the measured value PV. Various methods for measuring the change speed of the measured value PV for performing, for example, fuzzy control have been proposed.

FIG. 4 is a diagram for explaining a conventional operation relating to speed measurement in a case where the measured value PV increases. In FIG. 4, reference symbol PVL denotes a lower limit value of the measurement range, reference symbol PVH denotes an upper limit value of the measurement range, and the measurement range ΔPV is ΔPV.
= (PVH-PVL). Further, the vertical dashed line indicates the sampling timing of the measured value PV,
The sampling period is represented by t (the same applies hereinafter). In FIG. 4, the solid line rising to the right indicates the true measured value PV.
, And shows a case where the measurement value is in a state shown by a cross due to noise at each sampling timing of the measurement value PV.

In the case of the example shown in FIG. 4, the first method of measuring the average speed is as follows: from the last data of the measured value PV <the lower limit value PVL to the first data of the measured value PV> the upper limit value PVH, Period (T1) during which the measured value PV changes within the measurement range
It is a method. In this case, the measurement range P of the measurement value PV
The average speed V1 of VL to PVH is as follows: V1 = ΔPV / T1 (1)

[0005] In a second method, the measured value PV falls within the measured value range (PVL≤PV≤PVH) from the first data when the measured value PV falls within the measured range (PVL≤PV≤PVH).
Is the period (T2) during which the measured value PV changes in the measurement range up to the last data. In this case, the average speed V2 in the measurement range PVL to PVH of the measurement value PV is as follows: V1 = ΔPV / T2 (2)

In a third method, a change rate of the measured value PV is calculated for each sampling period until the measured value PV enters the measurement range and goes out of the measurement range, and the average value is calculated as the average speed. It is a method.

[0007]

However, each of such measurement techniques has the following problems. That is, the measurement value is affected by the control target and the installation environment of the control device that controls the control object, and a large noise rides on the measurement value PV and fluctuates more than the true measurement value PV as indicated by the cross mark in FIG. In this case, the calculated average speed tends to be inaccurate. That is, the transition of the true measurement value PV indicated by the solid line rising to the right in FIG. 4 is that the number of sampling cycle intervals of the measurement value PV indicated by the vertical broken line is eight, and the measurement range PV of the measurement value PV
The average speed V of L to PVH is as follows: V = ΔPV / 8t (3)

However, in the case where the measured value is affected by noise as shown in FIG. 4 and becomes a state as indicated by a cross, the first method described above uses the period T1 during which the measured value PV changes in the measurement range. = 2t, and the measurement range PVL to PV of the measured value PV
The average speed V1 of H is as follows: V1 = ΔPV / 2t (4)

In the second method, the period T1 = 16t
The average speed V2 in the measurement range PVL to PVH of the measured value PV is as follows: V2 = ΔPV / 16t (5) Therefore, it is difficult to accurately measure both of the first and second methods.

Furthermore, as in the third method, the measured value PV
In the method of calculating the rate of change of the measured value PV for each sampling cycle from the time when the measured value PV enters the measuring range to the time when the measured value PV comes out of the measuring range, and using the average value as the average speed, It is good if the noise rises and falls evenly, but if the average value of the noise is not zero with respect to the plus side and minus side of the measured value within the measurement range, the error will increase and it will be difficult to make accurate measurements as well. Met. for that reason,
It has been desired to provide a speed measuring device capable of measuring an average speed close to the average speed of the true measured value PV even in an environment with much noise.

The present invention has been made to solve such a conventional disadvantage, and an object of the present invention is to provide a simple speed measuring device having a structure capable of measuring an average speed close to the average speed of true measured values.

[0012]

According to a first aspect of the present invention, there is provided a speed measuring apparatus for measuring a deviation between a target value and a measured value or an average speed when the measured value rises. It has a measurement range storage unit for storing upper and lower limit values relating to a measurement range to be measured, first to third counters, and a comparison operation unit for calculating and outputting the average speed based on the input deviation or measured value. are doing.

In particular, the comparison operation section refers to the measurement range in the measurement range storage section, and advances the count of the first counter when the deviation or the measured value is larger than the upper limit value, and advances the second counter when the deviation or the measured value is within the measurement range. When the count value of the third counter is less than the lower limit value, the count value of the third counter is increased. When the count value of the second counter value changes from 0 to 1, the measurement of the first and third counters is started. When the count value of the third counter exceeds the count value of the second counter, the measurement is invalidated, all counters are cleared, and the count value of the first counter is When the count value is exceeded, the measurement is terminated, the average speed is calculated and output from the count value of the second counter, and all counters are cleared. .

A second configuration according to the speed measuring apparatus of the present invention stores an upper limit and a lower limit related to a measurement range for measuring a deviation between a target value and a measured value or an average speed when the measured value falls. It has a measurement range storage unit, first to third counters, and a comparison operation unit, and the comparison operation unit sets the start of measurement when the count value of the second counter changes from 0 to 1. The count values of the first and third counters are cleared, and when the count value of the first counter exceeds the count value of the second counter, all counters are cleared as measurement invalidation and the third counter is cleared. When the count value of the counter exceeds the count value of the second counter, the measurement is terminated, the average speed is calculated and output from the count value of the second counter, and all counters are cleared. That.

Further, the present invention relates to the above-described first and second embodiments.
In the above configuration, it is preferable that each of the comparison operation units is formed so as to calculate and output the average speed when the count value of the second counter exceeds a predetermined count value of 2 or more at the end of the measurement.

[0016]

According to the first configuration of the present invention, when the above-mentioned deviation or measured value is input to the comparison calculation unit, the comparison calculation unit reads the measurement range stored in the measurement range storage unit. Reference, a deviation or measured value larger than the upper limit value is counted by the first counter, and a deviation or measured value within the measuring range is counted by the second counter. Let the counter count. The comparison operation unit compares the count values of the first to third counters, and when the deviation or the measured value increases and determines that the measurement is to be started and that the measurement is to be completed, the count value of the second counter is determined. Calculates and outputs the average speed.

Further, according to the second configuration of the present invention, when the above-mentioned deviation or measured value is input to the comparison operation unit, the comparison operation unit refers to the measurement range stored in the measurement range storage unit. Then, a deviation or measurement value larger than the upper limit value is counted by the first counter, and a deviation or measurement value within the measurement range is counted by the second counter. When the deviation or measurement value is smaller than the lower limit value, the third counter is used. The comparison operation unit compares the count values of the first to third counters,
When the deviation or the measured value decreases and it is determined that the measurement has started and the measurement has been completed, the average speed is calculated and output from the count value of the second counter.

In the above-described configuration, the comparison operation section is formed so as to calculate and output the average speed when the count value of the second counter exceeds a predetermined count value of 2 or more at the end of the measurement. Is very large, the error of the calculated average speed can be suppressed to a finite range, and the average speed can be calculated with a predetermined accuracy.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing one embodiment of a speed measuring device according to the present invention. In FIG. 1, a comparison operation unit 1
Inputs a measured value PV as a control amount from the control target 3 and a deviation e obtained by subtracting the measured value PV from the target value SV by the subtraction unit 5, calculates an average speed thereof, and outputs the average speed to the control device 7, for example. It also controls the measurement range recording unit 9 and the first to third counters 11, 13, and 15.
Detailed functions of the comparison operation unit 1 will be described later.

In the following description, an example in which the average speed of the measured value PV is output will be described, but the same applies to the average speed of the deviation e. As shown in FIG. 2, the measurement range storage unit 9 stores at least one set of the upper limit value PVH and the lower limit value PVL of the measurement range for measuring the average speed. The value PVL is, for example, input and set from the control device 7 via the comparison operation unit 1. For example, it is selected from the control device 7 via the comparison operation unit 1 and used.

The first counter 11 counts the number of samplings of the measured value PV (deviation e) larger than the upper limit value PVH of the measuring range, and the second counter 13
Is a counter for counting the number of samplings of the measured value PV (deviation e) within the measurement range (upper limit value PVH to lower limit value PVL), and the third counter 15 measures the measured value PV less than the lower limit value PVL of the measurement range. It counts the number of samplings of (deviation e), and is managed by the comparison operation unit 1. The sampling of the measured value PV is performed, for example, in the comparison operation unit 1 or at an appropriate place in a preceding stage (not shown).

The comparison operation unit 1 includes first to third counters 1
It has a function of comparing the magnitude relationship of the count values in 1 to 15 to determine the start of measurement of the average speed, the invalidity of the measurement, or the end of the measurement. ing. That is, the comparison operation unit 1
The input measured value PV is referred to as the upper limit value PVH and the lower limit value PVL, which are the measurement ranges from the measurement range storage unit 7, and the measured value P
When V is larger than the upper limit value PVH, the count value of the first counter 11 is counted up one by one for each sampling, and the measurement range is from the upper limit value PVH to the lower limit value P
When it is within VL, the second counter 13
Is counted up one by one, and the lower limit PV
When it is smaller than L and smaller than L, it has a function of counting up the count value of the third counter 15 one by one every sampling.

When the measured value PV exceeds the lower limit value PVL and enters the measurement range, the comparison operation unit 1 starts the measurement and clears the count values of the first and third counters 11 and 15. have. Further, when the count value of the third counter 15 exceeds the count value of the second counter 2, the comparison operation unit 1 determines that the measurement is invalid,
It has a function of clearing the count values of the first to third counters 11 to 15, and further determines that the measurement has ended when the count value of the first counter 11 exceeds the count value of the second counter 13, It has a function of storing the count value (y) of the second counter 13 and clearing the count values of the first to third counters 11 to 15.

Next, the operation of the speed measuring apparatus of the present invention will be described with reference to FIG. FIG. 2 is a diagram illustrating a case where the measurement value becomes a cross mark due to the influence of noise or the like at each sampling timing indicated by a vertical broken line, with the solid line rising to the right as the transition of the true measurement value PV. 4 shows a similar situation. In FIG. 2, the measured value is the first (PV of x mark)
Is less than the lower limit value PVL, the third counter 15 is counted up one by one by the output from the comparison operation unit 1, and the measured value (PV marked with X) has entered the measurement range beyond the lower limit value PVL. At this time, the comparison operation unit 1 changes the count value of the second counter 13 from 0 to 1 to start measurement,
The count values of the first and third counters 11 and 15 are cleared.

After that, the measured value (PV indicated by x) becomes the lower limit P
Since the count value is lower than VL, the count-up of the third counter 15 continues, and when the count value of the third counter 15 exceeds the count value of the second counter 13, the comparison operation unit 1 determines that the measurement is invalid. The determination is made, and the count values of the first to third counters 11 to 15 are cleared. In this example, the count values of the second and third counters 13 and 15 are cleared as indicated by (0) in FIG.

Next, when the measured value (PV marked X) exceeds the lower limit value PVL and enters the measurement range again, the comparison operation unit 1 changes the count value of the second counter 13 from 0 to 1 and performs measurement. As a start, the count values of the first and third counters 11 and 15 are cleared. After the start of the measurement, the comparison operation unit 1 sets the first to third values corresponding to the measured values (PVs marked with x).
Of the second counter 13 and the second counter 13 and the counter values of the second counter 13 and the first counter 11 are compared with each other. When the count value exceeds the count value of the second counter 13, it is determined that the measurement is invalid, and the process of invalidating the measurement is performed in the same manner as at the time.

When the count value of the first counter 11 ("9" in FIG. 2) exceeds the count value of the second counter 13 ("8" in FIG. 2), the comparison operation unit 1 terminates the measurement. Is determined, and the count value (y
= 8) and the first to third all counters 11
Clear the count value of ~ 15. Then, based on the count value “y = 8” of the second counter 13 at the end of the measurement, the comparison operation unit 1 calculates the average speed as the number of times of sampling the true measurement value (PV).

The operation in the comparison operation unit 1 is, for example, as follows. Average speed of measurement range PVL to PVH = (PVH-PVL) / [sample link period x value of counter 2 at the end of measurement y] = ΔPV / 8t (when y = 8) (6) And this (6) The average speed obtained by the equation is equal to the average speed of the true measured value PV of the above-described equation (3), and highly accurate measurement can be performed.

As described above, in the speed measuring device described above,
The deviation between the target value and the measured value or the measured value is input to the comparison operation unit 1, and the comparison operation unit 1 compares the measurement range of the measurement range storage unit 7 with the deviation or the measured value. First counter 11 when greater than upper limit value PVH
Is counted by the second counter 1 when within the measurement range.
When the count of the third counter 15 is smaller than the lower limit value PVL, the count of the third counter 15 is advanced.
However, when the count value of the second counter 13 changes from 0 to 1, the first and third counters 11,
When the count value of the third counter 15 exceeds the count value of the second counter 13, the measurement is invalidated, the count values of all the counters 11 to 15 are cleared, and the first counter 11 is cleared. When the count value exceeds the count value of the second counter 13, all the counters 11 to 15 are cleared as the measurement end, and when it is determined that the measurement is finished, the average speed is calculated and output from the count value of the second counter 13. The configuration was adopted.

For this reason, the deviation or measured value is measured in the measuring range PV.
The number of samplings in H to PVL can be accurately counted, and when the count value exceeds a predetermined number, the average speed is calculated using the count number, so that a value close to the accurate average speed can be obtained. Even in an environment where there is a lot of data, an average speed close to the true measured value PV can be measured.

Further, in the speed measuring apparatus of the present invention, the error decreases as the count value (y) of the second counter 13 after the measurement ends, but the error of the average speed calculated with the count value 2 or more is finite. Since the value falls within the range, if the lower limit of the count value of the second counter 13 is set to 2 or more, the error in the calculated average speed can be set to a finite range even when the deviation or the change in the measured value is fast, The comparison operation unit 1 may be formed accordingly. That is, FIG.
As shown in (b), when the count value (y) of the second counter 13 at the end of the measurement is less than 2, the input measurement value (PV indicated by x) greatly changes and jumps over the measurement range PVH to PVL or performs measurement. If the number of samplings in the range PVH to PVL is small, the measured value outside the measurement range cannot be specified, and the calculated average error is infinite.

Therefore, in order to perform more accurate speed calculation, only when the count value (y) of the second counter 13 at the end of the measurement is 2 or more as shown in FIGS. 3 (c) and 3 (d). You should enable the measurement. FIG. 3C shows an example in which two measurement points are substantially within the measurement range. The average speed Vc is as follows: Vc = ΔPV / t (7), and FIG. This is the case where there are two measurement points just outside the one measurement point and the measurement range line, and the average speed Vd is as follows: Vd = ΔPV / 3t (8) Therefore, when the count value (y) is 2, The error range becomes the range between Vc and Vd, and the error becomes finite.

Therefore, the second counter 1 at the end of the measurement
The measurement may be effective only when the count value (y) of 3 is 2 or more, and the error decreases as the count value increases. However, setting a large predetermined count value limits the maximum value of the measurable speed,
It is preferable to form the comparison operation unit 1 and the second counter 13 so as to set a predetermined count value according to the type of the measurement target, the sampling period, and the like.

Further, the first to third counters 11 to 15 according to the present invention are formed separately from each other.
The storage means may be divided appropriately and used, or the above-described comparison operation unit 1, subtraction unit 5, measurement range storage unit 9 and the like may be configured together with the control device 7 or separately by a microcomputer or the like. Or a RAM connected to it. Furthermore, the above-mentioned first to first
It goes without saying that the counting method in the third counters 11 to 15 includes counting up and counting down. The above-described embodiment has been described by taking as an example a case where the measured value PV rises from a state below the lower limit value PVL to exceed the upper limit value PVH. However, in the present invention, the measured value falls from the upper limit value PVH to the lower limit value PVH.
It is feasible in situations where it falls below L.

As described above, in the second configuration corresponding to the descending measured value PV, when the count number of the second counter 13 changes from 0 to 1, the first and third counters 11 and 15 are used as measurement start. Is cleared, and when the count of the first counter 11 exceeds the count of the second counter 13, the measurement is invalidated and all the counters 1 are disabled.
Clear the count numbers 1 to 15 and set the third counter 15
When the count number of the second counter 13 exceeds the count number of the second counter 13, the counts of all the counters 11 to 15 are cleared as the measurement end, and the second count when the measurement end is determined.
The above-described comparison operation unit 1 may be configured to calculate and output the average speed from the count number of the counter 13.

That is, the control of the third counter 15 and the first counter 11 in the above-described embodiment of FIG. 1 may be changed in the opposite manner, and the first and third counters 11 and 11 in FIG. , 15 may be alternately replaced.

[0037]

As described above, the first configuration according to the speed measuring apparatus of the present invention compares the deviation between the target value and the measured value or the measured value with the measuring range, and compares the deviation and the measured value with the measuring range. The first count number larger than the upper limit value, the second count number within the measurement range, and the third count number less than the lower limit value of the measurement range are counted, and the second count number changes from 0 to 1. The first and third
Is cleared, and when the third count exceeds the second count, measurement is invalidated and all counts are cleared. When the first count exceeds the second count, measurement is terminated. Since all counts are cleared and the average speed is calculated and output from the second count when it is determined that measurement has been completed, the number of samplings whose rising deviation or measured value is within the measurement range can be accurately counted and the predetermined When the number is exceeded, the average speed is calculated using the count number. Therefore, even in a noisy environment, an average speed close to the average speed of the rising true measurement value can be measured. Further, the second configuration according to the present invention compares the deviation between the target value and the measured value or the measured value with the measurement range, and determines whether the deviation or the measured value is larger than the upper limit of the measurement range. The second count number within the range and the third count number less than the lower limit value of the measurement range are respectively counted, and when the second count number changes from 0 to 1, the first and third counts are taken as measurement start. When the first count exceeds the second count, measurement is invalidated and all counts are cleared. When the third count exceeds the second count, measurement is terminated. The average speed is calculated and output from the second count number when the measurement is determined to be completed.
When the descending deviation or measured value can accurately count the number of samplings in the measurement range, and when the number exceeds a predetermined number, the average speed is calculated using the counted number. An average speed close to the average speed of the measured values can be measured. Further, if the average speed is calculated and output when the second counter number exceeds a predetermined count value of 2 or more, even if the deviation or the change of the measured value is very large, the error of the calculated average speed is limited. The average speed can be calculated with a predetermined accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing one embodiment of a speed measuring device according to the present invention.

FIG. 2 is a diagram for explaining the operation of the speed measuring device of FIG.

FIG. 3 is a diagram for explaining another embodiment of the speed measuring device of the present invention.

FIG. 4 is a diagram illustrating the operation of a conventional speed measuring device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 comparison operation unit 3 control object 5 subtraction unit 7 control device 9 measurement range storage unit 11 first counter 13 second counter 15 third counter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Masashi Shimada 5-16-6 Kugahara, Ota-ku, Tokyo Rika Kogyo Co., Ltd. (56) References JP-A-3-163362 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01P 3/42-3/68 G05B 11/36 503 G05B 19/05 G05D 13/62

Claims (3)

(57) [Claims] 1. A measurement range storage unit for storing an upper limit value and a lower limit value of a measurement range for measuring a deviation between a target value and a measurement value or an average speed of the measurement value, a first counter, and a second counter. A third counter, referring to the measurement range of the measurement range storage unit for the input deviation or measured value, and when the deviation or measured value is greater than the upper limit value, advance the count of the first counter; When the count is within the measurement range, the count of the second counter is advanced, and when the count is less than the lower limit, the count of the third counter is advanced, and the first to third counts are performed based on the following (a) to (c). A speed measurement device, comprising: a comparison operation unit that controls the counter to start the measurement and, when it is determined that the measurement ends, to calculate and output the average speed from the count value of the second counter. (A) The measurement is started when the count value of the second counter changes from 0 to 1, and the count values of the first and third counters are cleared. (B) When the count value of the third counter exceeds the count value of the second counter, measurement is invalidated, and all the counters are cleared. (C) When the count value of the first counter exceeds the count value of the second counter, the measurement is terminated, and all the counters are cleared. 2. A measurement range storage unit for storing an upper limit value and a lower limit value of a measurement range for measuring a deviation between a target value and a measurement value or an average speed of the measurement value, a first counter, and a second counter. A third counter, referring to the measurement range of the measurement range storage unit for the input deviation or measured value, and when the deviation or measured value is greater than the upper limit value, advance the count of the first counter; When the count is within the measurement range, the count of the second counter is advanced, and when the count is less than the lower limit, the count of the third counter is advanced, and the first to third counts are performed based on the following (a) to (c). A speed measurement device, comprising: a comparison operation unit that controls the counter to start the measurement and, when it is determined that the measurement ends, to calculate and output the average speed from the count value of the second counter. (A) The measurement is started when the count value of the second counter changes from 0 to 1, and the count values of the first and third counters are cleared. (B) When the count value of the first counter exceeds the count value of the second counter, measurement is invalidated and all the counters are cleared. (C) When the count value of the third counter exceeds the count value of the second counter, the measurement is terminated, and all the counters are cleared. 3. The comparison calculation unit calculates and outputs the average speed when the count value of the second counter exceeds a predetermined count value of 2 or more at the end of the measurement. Speed measuring device.