KR101288944B1 - Flow rate measuring algorithm of digital meter using ＭＦ sensor - Google Patents

Abstract

The present invention relates to a flow rate measurement algorithm of a digital meter using the MF sensor, in particular, the sensing step of outputting an analog signal by sensing a magnet moving in accordance with the flow of the fluid through the MF sensor, and the output analog signal to the digital signal And a converting step of converting the signal into an analog signal, wherein the analog signal includes a first output voltage and a second output voltage, and in the converting step, the digital signal includes a first pulse signal and a second pulse signal. The first output voltage and the second output voltage has a phase difference of 45 degrees, and the first pulse signal and the second pulse signal have a phase difference of 45 degrees, thereby reducing mechanical rotation, thereby reducing mechanical noise, and one sensor. MF detects forward and reverse rotation, chattering and magnetic field changes due to external influences to increase measurement accuracy. It relates to a flow rate measurement algorithm of the digital meter with the document.

Description

Flow rate measuring algorithm of digital meter using MF sensor

The present invention relates to a flow rate measurement algorithm of a digital meter using the MF sensor, in particular, the sensing step of outputting an analog signal by sensing a magnet moving in accordance with the flow of the fluid through the MF sensor, and the output analog signal to the digital signal And a converting step of converting the signal into an analog signal, wherein the analog signal includes a first output voltage and a second output voltage, and in the converting step, the digital signal includes a first pulse signal and a second pulse signal. The first output voltage and the second output voltage have a phase difference of 45 degrees, and the first pulse signal and the second pulse signal also relates to a flow rate measuring algorithm of a digital meter using an MF sensor having a phase difference of 45 degrees.

1 is a schematic block diagram of a conventional flow sensing system.

The flow rate sensing system includes a flow rate sensing unit 110, a display unit 120, a central processing unit 130, a memory 140, a battery 150, a battery monitoring unit 160, and a communication unit 170.

Here, the flow rate sensing device 110 is composed of a first sensor 112, a second sensor 114, a magnetic portion 116 and an impeller 118. When the fluid starts to flow through the supply pipe, the impeller 118 rotates. When the impeller 118 starts to rotate, the magnetic part 116 connected to the same rotating shaft as the impeller 118 also rotates. As the magnetic unit 116 rotates, the first sensor 112 and the second sensor 114 detect a change in the polarity of the magnetic unit 116, and transmit the detected result to the central processing unit 130. The second sensor 114 works with the first sensor 112 to be used to determine the flow direction and flow rate of the fluid.

When the fluid flows from left to right as in the example of FIG. 1, the second sensor 114 first detects the change in the magnetism, and then the first sensor 112 detects the change in the magnetism. In the case where the fluid flows in the opposite direction, the first sensor 112 first detects the change in the magnetic property, and then the second sensor 114 detects the change. As such, the direction in which the fluid flows may be determined according to which part of the first sensor 112 and the second sensor 114 first detects a change in magnetic property.

When the number of changes in the direction and the direction of the fluid is measured by the first sensor 112 and the second sensor 114 and transmitted to the central processing unit 130, the central processing unit 130 is These signals are calculated and converted into values of the flow rate and then displayed through the display unit 120. The display unit 120 displays not only the flow rate but also information of the flow rate detection system such as the flow rate and the device state so that the operator can view it.

The first and second sensors 112 and 114 mainly use a magnetoresistive (MR) sensor or a hall (Hall) sensor, and the MR sensor is a sensor using a magnetoresistive effect. It is a sensor that can be detected by the change of, and the Hall sensor is a sensor used to detect the speed or position by using the Hall electromotive force generated by the magnetic field according to the Hall Effect.

The memory 140 stores the information required by the flow rate sensing system such as the flow rate value, flow rate, and direction.

The battery 150 has a life span of at least 5 years when it is once installed because of the characteristics of the flow sensing system, which supplies power required for the flow sensing system but is difficult for the operator to maintain frequently. The battery monitoring unit 160 monitors the state of the battery 150, for example, abnormality, residual voltage, and the like, and informs the central processing unit 130 of this.

The communication unit 170 is connected to a wired / wireless network or a telephone network (PSTN), and performs a function of transmitting a weighing value and various flow rate information to a meter reading center (not shown).

2 is a view showing the magnetic portion 116 of the conventional flow sensor.

The magnetic part 116 is a part which rotates together with the impeller 118 to measure the flow rate and the direction of the fluid, and the N pole 210 and the S pole 220 which rotate about the rotation axis 230 and the rotation axis 230. It is made of a magnet with. When the impeller 118 rotates as the fluid flows, the magnet also rotates due to the rotation of the rotating shaft 230. The conventional flow rate sensing device may detect the rotation of the impeller 118 in units of one rotation when detecting only one of the N pole and the S pole, and the impeller 118 when detecting both the S pole and the N pole. The rotation of can be detected in 1/2 rotation units.

Therefore, there is a problem in that a sensor must be additionally provided to detect a state change of more than 1/2 per revolution.

In addition, the conventional flow rate sensing device has a problem in that two sensors must be provided to detect the rotation direction of the impeller 118.

In the conventional digital gas meter having a periodic volume of 1.6 m ³ and a resolution of 200 CC, when one MR sensor is applied, the magnetic part 116 should be rotated 8 times per periodic volume, thereby generating noise due to rotation of the apparatus. .

In case of MR SENSOR or HALL IC applied to the conventional digital gas meter, the output signal is only 2 STATE of HIGH / LOW, so even if the STATE is changed by the external magnetic field, it cannot be detected. There is a problem that the oil flow rate value increases.

In addition, in case of MR SENSOR or HALL IC which is applied to the conventional flow sensing device, the output signal is only 2 STATE of HIGH / LOW, so when the sensor is located at the polar boundary of the circular magnet, there is a chattering on the output signal of the sensor. If there is a chattering caused by mechanical vibration or mechanical vibration, there is a problem that the accumulated flow value is increased because it is recognized as a normal state change.

Republic of Korea Patent Publication No. 10-2005-0010449

The present invention has been made to solve the above-described problem, and by reducing the mechanical rotation to reduce the mechanical noise, to detect the forward and reverse rotation through one sensor, detect chattering, the magnetic field by external influence The purpose of the present invention is to provide a flow measurement algorithm of a digital meter using an MF sensor that detects a change and improves measurement accuracy.

Flow measuring algorithm of the digital meter using the MF sensor of the present invention for achieving the above object, the sensing step of outputting an analog signal by sensing a magnet moving in accordance with the flow of the MF sensor, and the output analog signal And converting the digital signal into a digital signal, wherein the analog signal includes a first output voltage and a second output voltage, and the digital signal includes a first pulse signal and a second pulse signal. The first output voltage and the second output voltage have a phase difference of 45 degrees, and the first pulse signal and the second pulse signal have a phase difference of 45 degrees.

After the conversion step,

A first judging step of determining that the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are different from each other;

Does not correspond to the first judging stage,

And a second judging step of determining that the magnet is not rotated when both the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same.

It does not correspond to the first judgment step and the second judgment step

And a third judging step of determining that chattering has occurred when both the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same.

It does not correspond to the first judging step, the second judging step, or the third judging step,

When the current first pulse signal and the previous first pulse signal are the same and the current second pulse signal and the previous second pulse signal are different,

And determining a forward rotation when the previous first pulse signal and the second pulse signal are the same, and determining the reverse rotation when the previous first pulse signal and the second pulse signal are different from each other.

It does not correspond to the first judging step, the second judging step, the third judging step, the fourth judging step,

When the current first pulse signal and the previous first pulse signal are different and the current second pulse signal and the previous second pulse signal are the same,

And determining a reverse rotation when the previous first pulse signal and the second pulse signal are the same, and determining the forward rotation when the previous first pulse signal and the second pulse signal are different from each other.

According to the flow measurement algorithm of the digital meter using the MF sensor of the present invention as described above, has the following effects.

A sensing step of sensing a magnet moving in accordance with the flow of the fluid through the MF sensor and outputting an analog signal, and converting the output analog signal into a digital signal, wherein the analog signal is a first output voltage. And a second output voltage, wherein, in the converting step, the digital signal includes a first pulse signal and a second pulse signal, and the first output voltage and the second output voltage have a phase difference of 45 degrees. The pulse signal and the second pulse signal also have a phase difference of 45 degrees, and in the converting step, the digital signal has eight state changes per one revolution of the magnet, thereby reducing mechanical rotation to one eighth and reducing noise caused by the rotation of the object. Can be reduced.

After the conversion step,

If both the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are different from each other, it is determined that the external influence is effected (first determination step). Measurement accuracy can be increased.

Does not correspond to the first judging stage,

If both the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same, it may be determined that the magnet is not rotated (second determination step).

It does not correspond to the first judgment step and the second judgment step

If both the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same, it is determined that chattering has occurred (third decision step), and the occurrence of chattering is detected to improve measurement accuracy. Can be.

It does not correspond to the first judging step, the second judging step, or the third judging step,

When the current first pulse signal and the previous first pulse signal are the same and the current second pulse signal and the previous second pulse signal are different,

If the previous first pulse signal and the second pulse signal are the same, it is determined to be a forward rotation, and if the previous first pulse signal and the second pulse signal are different, it is determined to be reverse rotation (fourth judging step). Rotation can be detected.

It does not correspond to the first judging step, the second judging step, the third judging step, the fourth judging step,

When the current first pulse signal and the previous first pulse signal are different and the current second pulse signal and the previous second pulse signal are the same,

If the previous first pulse signal and the second pulse signal are the same, it is determined as reverse rotation. If the previous first pulse signal and the second pulse signal are different, it is determined as forward rotation (fifth judging step). Rotation can be detected.

1 is a schematic block diagram of a conventional flow detection system
2 is a view illustrating a magnetic part of a conventional flow sensing device.
3 is an analog signal and a converted digital signal of the digital meter using the MF sensor according to an embodiment of the present invention.
Figure 4 is a flow rate measurement algorithm of the digital meter using the MF sensor in accordance with a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

For reference, the same components as those of the conventional art will be described with reference to the above-described prior art, and a detailed description thereof will be omitted.

The present invention is an algorithm for detecting forward / reverse rotation and increasing measurement accuracy in a meter for measuring flow rate by sensing mechanical rotational motion such as a digital water meter, a digital hot water meter, and a digital gas meter.

The following embodiment takes a digital gas meter as an example and applies equally to other digital meters.

3 and 4, the flow rate measurement algorithm of the digital meter using the MF sensor of the present embodiment, the sensing step of outputting an analog signal by detecting a magnet moving in accordance with the flow of the fluid through the MF sensor, and the output Converting the converted analog signal into a digital signal, wherein the analog signal includes a first output voltage and a second output voltage, and in the converting step, the digital signal includes a first pulse signal and a second pulse. And a pulse signal, wherein the first output voltage and the second output voltage have a phase difference of 45 degrees such that the first pulse signal and the second pulse signal have a phase difference of 45 degrees.

In the sensing step, an analog signal is output by detecting a magnet moving in accordance with the flow of the fluid through a magnetic field sensor. The magnet may be a permanent magnet.

As shown in FIG. 3, in the sensing step, the analog signal includes a first output voltage and a second output voltage, and the first output voltage and the second output voltage have a phase difference of 45 degrees. As described above, the MF sensor generating the cos (2a) and sin (2a) analog signals having a phase difference of 45 degrees when the angle between the sensor and the field direction is a is not well known in the art, but is known in the art. Since the sensor technology, a description thereof will be omitted. For example, these MFP sensors appear in a catalog published by Philips in 2009 (product number KMZ43T) (see www.nxp.com).

The converting step converts the first and second analog signals output using the comparator into digital signals. That is, as shown in FIG. 3, the sinusoidal analog signal may be replaced with the first and second digital signals as 1 when the value is greater than or equal to a certain value and 0 when the value is less than or equal to the predetermined value.

In the converting step, the digital signal has a first pulse signal converted from the first output voltage and a second pulse signal converted from the second output voltage.

The first output voltage and the second output voltage have a phase difference of 45 degrees, so that the first pulse signal and the second pulse signal have a phase difference of 45 degrees.

The first pulse signal and the second pulse signal are as shown in Table 1 below. In the following table, the first pulse signal is VOUT1 and the second pulse signal is VOUT2.

<Table 1>

For this reason, the present invention can check the regular state change according to the rotation of the magnet, as shown in Table 1, it can be confirmed 8 state changes per rotation of the magnet. In addition, as shown in Table 2, the first pulse signal and the second pulse signal are alternately changed in value.

<Table 2>

As such, the present invention can use 8 state changes per revolution, so that the rotational speed of the magnet can be reduced to 1/8 compared to the conventional digital gas meter, thereby reducing the noise caused by the rotation of the apparatus.

After the conversion step, the first pulse signal and the second pulse signal detected by the current sensor (hereinafter referred to as 'now') (hereinafter referred to as 'previous') and previously detected by the sensor (hereinafter referred to as 'previous') (PO1) A first determination step S3 of determining whether the first pulse signal and the second pulse signal are different.

If the first pulse signal and the second pulse signal of the current (PO0) and the first pulse signal and the second pulse signal of the previous (PO1) are all different, it is determined that the external influence.

<Table 3>

As shown in Table 3, when the magnet rotates quickly and the MFF sensor does not detect the rotation of the magnet, a slip occurs or when an external magnetic field affects the MFF sensor. The pulse signal and the second pulse signal are different from both the first and second pulse signals of the previous PO1.

On the other hand, the sampling rate (SAMPLING RATE) setting for detecting the MF sensor in the digital gas meter (digital meter) is set in consideration of the rotational speed of the magnet so that no slip occurs.

Therefore, when the first pulse signal and the second pulse signal of the current (PO0) and the previous (PO1) are different in the first determination step (S3), it is determined that the external magnetic field is affected and does not add up the flow rate value. Do not.

Further, thereafter, a second determination step S7 of determining whether the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same.

If the first pulse signal and the second pulse signal of the current PO0 and the first pulse signal and the second pulse signal of the previous PO1 are the same, it is determined that the magnet does not rotate.

If neither the first pulse signal nor the second pulse signal of the current PO0 and the first pulse signal and the second pulse signal of the previous PO1 are the same or different from each other, then the first pulse signal of the current PO0 is next. And a third determination step S11 of determining whether the second pulse signal, the first pulse signal before the previous PO2 and the second pulse signal are the same, and as shown in Table 4, If both the first pulse signal and the second pulse signal and the first pulse signal and the second pulse signal before the previous PO2 are the same, it is determined that chattering has occurred.

In this way, chattering can be detected to further increase measurement accuracy.

<Table 4>

The chattering may be caused by mechanical vibration of the magnet or may occur at an extreme boundary portion of the magnet.

For this reason, when the chattering occurs, the magnet rotates forward and backward.

Therefore, when the chattering occurs, both the first and second pulse signals of the current PO0 and the previous PO2 become the same.

For this reason, by comparing the values of the current (PO0) and the previous (PO2) of the first pulse signal and the second pulse signal, it can be determined that chattering if all values are the same. When it is determined as chattering as described above, the flow rate value is not integrated, so that the flow rate can be accurately measured.

Furthermore, when the external influence is detected or the chattering is detected as described above, the user may be notified so that the user may immediately know that an error has occurred.

If there is no influence of the above chattering or external magnetic field, the first pulse signal of current (PO0) and the first pulse signal of previous (PO1) are different, or the second pulse signal of current (PO0) and the previous (PO1) The second pulse signal of) must be different.

If the first pulse signal of the current PO0 is the same as the first pulse signal of the previous PO1 and the second pulse signal of the current PO0 is different from the second pulse signal of the previous PO1, the previous (PO1) If the first pulse signal and the second pulse signal are the same, it is determined as forward rotation, and if the first and second pulse signals of previous (PO2) are not equal, it is determined as reverse rotation.

If the first pulse signal of the current PO0 is different from the first pulse signal of the previous PO1 and the second pulse signal of the current PO0 is the same as the second pulse signal of the previous PO1, the previous (PO1) If the first pulse signal and the second pulse signal are the same, it is determined as reverse rotation, and if the first pulse signal and the second pulse signal are not equal to the previous (PO2), it is determined as forward rotation.

<Table 5>

<Table 6>

Table 5 shows the flow of the first pulse signal and the second pulse signal when rotating in the forward direction, and Table 6 shows the flow of the first pulse signal and the second pulse signal when rotating in the reverse direction.

As shown in Table 5, in the forward rotation, the first pulse signal of the current PO0 and the first pulse signal of the previous PO1 are different, and the second pulse signal of the current PO0 and the second of the previous PO1 are different. When the pulse signal is the same, the first pulse signal of the previous (PO1) and the second pulse signal are different, and the first pulse signal of the current (PO0) and the first pulse signal of the previous (PO1) are the same and the current of the current (PO0) When the two pulse signal is different from the second pulse signal of the previous PO1, the first pulse signal and the second pulse signal of the previous PO1 are the same.

As shown in Table 6, in the reverse rotation, the first pulse signal of the current PO0 is different from the first pulse signal of the previous PO1, and the second pulse signal of the current PO0 and the first of the previous PO1 are different. When the two pulse signals are the same, the first pulse signal of the previous (PO1) and the second pulse signal are the same, the first pulse signal of the current (PO0) and the first pulse signal of the previous (PO1) are the same and the current (PO0) When the second pulse signal is different from the second pulse signal of the previous PO1, the first pulse signal and the second pulse signal of the previous PO1 are different.

Accordingly, it is determined whether the first pulse signal of the current PO0 is the same as the first pulse signal of the previous PO1 and the second pulse signal of the current PO0 is different from the second pulse signal of the previous PO1 (S15). ), If the first pulse signal of the current PO0 and the previous first pulse signal are the same and the second pulse signal of the current PO0 and the second pulse signal of the previous PO1 are different, the first pulse of the previous PO1 is different. It is determined whether the signal and the second pulse signal are the same (S17). If it is equal, it is determined as forward rotation (S19), and if not, it can be determined as reverse rotation. (S21)

Further, if the first pulse signal of the current PO0 and the first pulse signal of the previous PO1 are different and the second pulse signal of the current PO0 and the second pulse signal of the previous PO1 are the same, the previous (PO1) It is determined whether the first pulse signal and the second pulse signal are the same (S23). If it is the same, it can be determined as the reverse rotation, and if not, it can be determined as the forward rotation.

In this way, if it is detected that the flow of fluid flows in the forward direction, the integrated unit flow rate is integrated according to the resolution.

In addition, if it is detected that the fluid flows in the opposite direction, the integrated unit flow rate may be subtracted according to the resolution.

This allows the present invention to accurately measure the unit flow rate with a simple configuration.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims .

DESCRIPTION OF REFERENCE NUMERALS

Claims (6)

Detecting a magnet moving in accordance with the flow of the fluid through the MF sensor to output an analog signal;
Converting the output analog signal into a digital signal;
In the sensing step, the analog signal includes a first output voltage and a second output voltage,
In the converting step, the digital signal includes a first pulse signal and a second pulse signal, and the first output voltage and the second output voltage have a phase difference of 45 degrees so that the first pulse signal and the second pulse signal are also 45 degrees. Has a phase difference of degrees,
The MF sensor generates a flow rate of the digital meter using the MF sensor, characterized in that for generating an analog signal in the form of c (2a) and cini (2a) having a phase difference of 45 degrees when the angle between the MF sensor and the field direction is a Measurement algorithm. The method of claim 1,
After the conversion step,
And a first judging step of determining whether the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are different from each other, and the current first pulse signal and the second pulse signal The flow rate measurement algorithm of the digital meter using the MF sensor, characterized in that if the previous first pulse signal and the second pulse signal is different, it is determined that the external influence. 3. The method according to claim 1 or 2,
After the conversion step,
And a second judging step of judging whether the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same, and including the current first pulse signal and the second pulse signal. And if the previous first pulse signal and the second pulse signal are the same, it is determined that there is no rotation of the magnet. 3. The method according to claim 1 or 2,
After the conversion step,
And a third judging step of determining whether the current first pulse signal and the second pulse signal and the previous first pulse signal and the second pulse signal are the same, and the current first pulse signal and the second pulse signal The flow rate measurement algorithm of the digital meter using the MF sensor, characterized in that it is determined that the chattering occurs if the first pulse signal and the second pulse signal before the same. 3. The method according to claim 1 or 2,
After the conversion step,
A fourth that determines whether the current first pulse signal is the same as the previous first pulse signal, the current second pulse signal is different from the previous second pulse signal, and whether the previous first pulse signal and the second pulse signal are the same. And including the determining step, wherein the current first pulse signal and the previous first pulse signal are the same, the current second pulse signal and the previous second pulse signal are different, and the previous first pulse signal and the second pulse signal are the same. The flow rate measurement algorithm of the digital meter using the MF sensor, characterized in that the forward rotation and the first pulse signal and the second pulse signal is different from the previous rotation. 3. The method according to claim 1 or 2,
After the conversion step,
A fifth that determines whether the current first pulse signal is different from the previous first pulse signal, the current second pulse signal is the same as the previous second pulse signal, and whether the previous first pulse signal and the second pulse signal are the same; And a determination step, wherein the current first pulse signal and the previous first pulse signal are different, the current second pulse signal and the previous second pulse signal are the same, and the previous first pulse signal and the second pulse signal are the same. The flow rate measurement algorithm of the digital meter using the MF sensor, characterized in that it is determined by the reverse rotation and the forward pulse if the previous first pulse signal and the second pulse signal is different.

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