JP7384551B2 - Diagnostic system, diagnostic method, diagnostic program and flow control device. - Google Patents

Description

The present invention relates to a diagnostic system, a diagnostic method, a diagnostic program, and a flow rate control device.

As disclosed in Patent Document 1, a diagnostic mechanism used in a flow rate control device (mass flow controller) includes a resistor that generates a differential pressure in a flow path through which a fluid flows, and a resistor on the upstream and downstream sides of the resistor. A flow rate sensor equipped with a pressure sensor provided in each of the flow rate sensors, and a valve that opens and closes a flow path on the upstream side of the flow rate sensor, reduces the pressure in the flow path with the flow path closed by the valve, and at this time Disclosed is a method for diagnosing the function of a flow rate sensor based on whether an output value obtained from a flow rate sensor or an output-related value (diagnosis parameter) that is a value related thereto differs from a predetermined reference value.

なお、Ｐ１は、上流側圧力センサの圧力値であり、Ｐ２は、下流側圧力センサの圧力値であり、Ｘは、ガス種によって変化する係数である。 Here, to explain the output-related value more specifically, the output-related value is the pressure difference between the pressures P1 and P2 measured by both pressure sensors after reducing the pressure in the flow path with the flow path closed with a valve. The mass flow rate Q is calculated using equation (1).

Note that P1 is the pressure value of the upstream pressure sensor, P2 is the pressure value of the downstream pressure sensor, and X is a coefficient that changes depending on the gas type.

Next, a mass flow rate integral value n is calculated using equation (2) in which the mass flow rate Q is time-integrated over a predetermined period of time during which the pressure measured by the upstream pressure sensor changes over time. In FIG. 5, the sum of the mass flow rates Q in the shaded area between a and b indicates the mass flow integral value n.

また、質量流量積分値ｎは、気体の状態方程式より式（３）のようにも表すことができる。

なお、Ｖは、診断用の体積値であり、Ｐ１_{ＳＴＡＲＴ}は、所定時間の始点において上流側圧力センサで測定された圧力であり、Ｐ１_ＥＮＤは、所定時間の終点において上流側圧力センサで測定された圧力である。

Further, the mass flow rate integral value n can also be expressed as in equation (3) from the gas equation of state.

Note that V is the volume value for diagnosis, P1 _START is the pressure measured by the upstream pressure sensor at the start point of the predetermined time, and P1 _END is the pressure measured by the upstream pressure sensor at the end point of the predetermined time. pressure.

なお、ｎは、モル数（式（１）を用いて算出した単位時間あたりの質量（質量流量Ｑ）を時間で積分したもの、すなわち、質量流量積分値ｎである。）であり、Ｒは、ガス種によって定まる気体定数であり、Ｔは、温度センサで測定される温度であり、ここでは、一定とみなしており、ΔＰ１は、所定時間の始点及び終点において上流側圧力センサで測定される圧力の圧力差である。 Then, the volume value V expressed by equation (4) derived from equation (2) and equation (3) becomes the output-related value.

Note that n is the number of moles (the mass per unit time (mass flow rate Q) calculated using formula (1) is integrated over time, that is, the mass flow rate integral value n), and R is , is a gas constant determined by the gas type, T is the temperature measured by the temperature sensor, which is assumed to be constant here, and ΔP1 is the temperature measured by the upstream pressure sensor at the start and end points of a predetermined time. It is the pressure difference.

Here, equations (3) and (4) include the temperature difference and pressure difference between the start point and end point of the predetermined time, but these values take into account changes in pressure and temperature during the predetermined time. It may also be the amount of change in pressure and the amount of change in temperature.

However, the output-related value expressed by equation (4) includes temperature and pressure, and these values cause an error in the volume value V. In other words, when trying to continuously measure pressure that changes over time using a pressure sensor, secondary pressure generated due to elements such as piping and various equipment connected downstream of the flow sensor will increase over time. This secondary pressure change affects the pressure measurement by the pressure sensor, so that measurement cannot be performed under the same measurement ambient conditions, and an error occurs in the volume value V based on this secondary pressure change. Similarly, the temperature also changes over time, and this temperature change affects the pressure measurement by the pressure sensor, making it impossible to measure under the same measurement ambient conditions, and the volume value V based on this temperature change. An error will occur.

Therefore, when attempting to diagnose the flow rate sensor based on the output-related value expressed by equation (4), there is a problem in that an error occurs in the output-related value, making it impossible to perform accurate diagnosis.

Patent No. 4881391

Therefore, the main object of the present invention is to diagnose the function of a flow rate sensor more accurately and to reduce misdiagnosis regardless of changes in measurement ambient conditions.

That is, the diagnostic system according to the present invention includes: an output-related value measuring section that measures an output-related value that is either the output value of the fluid sensor or a value related thereto; a reference value storage unit that stores a predetermined reference value for determining whether or not the output-related value is measured; and a correction unit that corrects at least one of the output-related value or the reference value in accordance with the measurement surrounding conditions of the output-related value. and a diagnosis section that diagnoses the fluid sensor based on the output-related value based on the correction result of the correction section and the reference value.

If this is the case, the output-related values or reference values are corrected according to the measurement ambient conditions such as fluid pressure and temperature that cause errors in the output-related values, and the output-related values are adjusted based on the correction results. Since the function of the fluid sensor is diagnosed based on the reference value, the function of the fluid sensor can be diagnosed more accurately, the diagnostic accuracy is improved, and misdiagnosis can be reduced accordingly. Note that the output-related value includes an output value of a fluid sensor or a value related thereto. When the fluid sensor is a flow rate sensor, the flow rate value is an output value of the flow rate sensor, a volume value is a value related to this flow rate value, etc. Further, specifically, when the correction unit corrects only the output-related value, the diagnosis unit diagnoses the fluid sensor based on the corrected output-related value and the uncorrected reference value, and When the correction unit corrects only the reference value, the flow rate sensor is diagnosed based on the uncorrected output-related value and the corrected reference body, and the correction unit corrects the output-related value and the reference value. Next, the fluid sensor is diagnosed based on the corrected output-related value and the corrected reference value.

The diagnostic system further includes a reference output-related value storage unit that stores a reference output-related value measured in advance under a reference measurement ambient condition and the measurement ambient condition in association with each other, and the correction unit includes: The output-related value or the reference value may be corrected based on a deviation between a measurement ambient condition associated with the output-related value and a measurement ambient condition associated with the reference output-related value.

With this type of device, the standard output-related values that serve as the basis for the standard values can be measured in the same way as the output-related values, and there is no need to add new sensors etc. to determine the standard values, simplifying the system. This makes it possible to reduce costs.

Further, in any of the diagnostic systems described above, the measurement ambient condition may include either pressure or temperature of the fluid. Note that the pressure of the fluid includes primary pressure and secondary pressure that occur due to the influence of piping and external equipment connected to the fluid sensor. Further, the temperature of the fluid includes a temperature that affects measurement by each sensor such as a pressure sensor.

Further, the output-related value may be a value based on a time-integrated value of the pressure of the fluid that changes over time. Specifically, the output-related value may be a value based on a mass flow rate integral value obtained by integrating a mass flow rate calculated based on a pressure difference between upstream and downstream sides of the fluid flow for a predetermined time. . More specifically, the output-related value is a fluid volume value calculated from the pressure change amount and temperature during the predetermined time upstream or downstream of the fluid flow, and the mass flow integral value. You can.

With such output-related values, even if there is local peak-dip noise in some of the pressure values when pressure that changes over time is measured continuously, the time-integrated value of that noise is small. Therefore, it is possible to reduce the influence of noise on output-related values, thereby improving diagnostic accuracy. In addition, with differential pressure mass flow controllers, each sensor that already has values for calculating output-related values can perform measurements, making it possible to diagnose flow rate sensors with high accuracy without adding additional sensors. can.

Further, in any of the above diagnostic systems, the flow rate adjustment mechanism further includes a flow rate adjustment mechanism that blocks the flow of the fluid, and the flow rate adjustment mechanism controls the pressure of the fluid on the upstream side or the downstream side by blocking the flow of the fluid. may change over time, and furthermore, the fluid sensor may include a resistor that generates a differential pressure between upstream and downstream sides of the fluid.

Note that the term "flow rate adjustment mechanism" refers not only to the flow control mechanism that constitutes a flow rate control device such as a differential pressure mass flow controller or a thermal mass flow controller, but also to the introduction of a mass flow controller separately from a mass flow controller. It also includes things like on-off valves installed on piping extending from ports and outlet ports. That is, any material that can open and close the fluid flow path may be used.

With this type of device, the function of the fluid sensor is diagnosed using the change in pressure over time for a very small flow path volume between the flow rate adjustment mechanism and the resistor, so the depressurization time is shortened, making it easier to diagnose. The required time can be shortened. Furthermore, if the differential pressure type mass flow controller is used, the flow rate sensor can be diagnosed using the originally provided mechanism.

Further, in the fluid sensor diagnosis method according to the present invention, an output-related value that is either an output value of the fluid sensor or a value related thereto is measured, and the output-related value or the output-related value is normal. Correcting at least one of predetermined reference values in order to determine whether The fluid sensor is characterized by diagnosing the fluid sensor.

Further, the program according to the present invention is a program used in a diagnostic system for diagnosing the function of a fluid sensor that measures fluid, and the program has an output value that is either an output value of the fluid sensor or a value related thereto. A related value is measured, and at least one of the output-related value or a predetermined reference value for determining whether or not the output-related value is normal is corrected according to the measurement surrounding conditions of the output-related value. The present invention is characterized in that a computer is caused to perform a function of diagnosing the fluid sensor based on the output-related value based on the correction result and the reference value.

Further, the flow rate control device according to the present invention includes a flow rate sensor that measures the flow rate of fluid;
a flow rate control mechanism that is provided upstream of the flow rate sensor and controls the flow rate of the fluid based on the output value of the flow rate sensor; and a value that is either the output value of the fluid sensor or a value related thereto. an output-related value measurement unit that measures an output-related value; a reference value storage unit that stores a predetermined reference value for determining whether or not the output-related value is normal; and the output-related value or the standard. a correction unit that corrects at least one of the output-related values according to measurement surrounding conditions of the output-related value; and a diagnosis that diagnoses the fluid sensor based on the output-related value and the reference value based on the correction result of the correction unit. The invention is characterized by comprising:

According to the present invention configured in this way, since the output-related value is diagnosed while taking into account the measurement surrounding conditions that cause errors in the output-related value, it is possible to diagnose the function of the fluid sensor more accurately. This can reduce misdiagnosis.

1 is a schematic diagram showing a flow rate control device according to Embodiment 1. FIG. FIG. 2 is a functional configuration diagram showing a control section of the flow rate control device according to the first embodiment. FIG. 3 is a cross-sectional view showing a resistor of the flow control device according to the first embodiment. 5 is a graph showing changes over time in pressure measured by an upstream pressure sensor in the flow rate control device according to the first embodiment. 7 is a graph for explaining a mass flow rate integral value in the flow rate control device according to the first embodiment. 3 is a flowchart showing a flow rate sensor diagnosis process of the flow rate control device according to the first embodiment. 3 is a flowchart showing a pressure sensor diagnosis process of the flow rate control device according to the first embodiment. 3 is a flowchart showing a flow control mechanism diagnosis process of the flow control device according to the first embodiment. FIG. 2 is a schematic diagram showing a flow rate control device according to a second embodiment.

EMBODIMENT OF THE INVENTION Below, the diagnostic system based on this invention is demonstrated with reference to drawings.

The diagnostic system according to the present invention diagnoses the function of a fluid sensor, and is incorporated into, for example, a flow rate measurement device or a flow rate control device (mass flow controller) that includes a flow rate sensor. Specific examples of the flow rate control device include, for example, a differential pressure type mass flow controller and a thermal type mass flow controller.

<Embodiment 1>
As shown in FIG. 1, the diagnostic system DS according to this embodiment includes a flow rate control device MF1 and on-off valves UV and DV provided on the upstream and downstream sides of the flow rate control device MF1. For example, it is used in a gas control system for supplying material gas and cooling gas to a film forming chamber in a semiconductor film forming apparatus.

The flow rate control device MF1 is a differential pressure type mass flow controller. Specifically, a flow path 10 through which a fluid flows, a flow rate sensor 20 that measures the flow rate of the fluid flowing through the flow path 10, a flow rate control mechanism 30 provided upstream of the flow rate sensor 20, and a flow rate control mechanism 30 provided upstream of the flow rate control mechanism 30. A pressure sensor 40 provided on the side for measuring supply pressure is provided.

Although not shown, the flow path 10 is provided with an introduction port at the upstream end and an outlet port at the downstream end. For example, the introduction port is connected to a gas supply mechanism that supplies gas to be introduced into the flow rate controller MF1 via piping, and the outlet port is connected to a gas supply mechanism whose flow rate is controlled by the flow rate controller via piping. It is connected to the film forming chamber to which gas is supplied.

The flow rate sensor 20 includes a resistor 50 that generates a pressure difference in the flow path 10, an upstream pressure sensor 60 that measures the pressure upstream of the resistor 50, and a downstream pressure sensor 60 that measures the pressure downstream of the resistor 50. It includes a pressure sensor 70 and a temperature sensor 80 that measures the temperature between the flow rate control mechanism 30 and the resistor 50. Note that both pressure sensors 60 and 70 are absolute pressure type pressure sensors.

As shown in FIG. 3, the resistor 50 generates a pressure difference between an inlet 50a on the upstream side and an outlet 50b on the downstream side. In addition, as for the specific structure, it mainly consists of two types of ring bodies 51 and 52, and the first ring body 51 has a smaller outer diameter and a larger inner diameter than the second ring body 52. The second ring body 52 has a larger outer diameter and a smaller inner diameter than the first ring body 51. The ring bodies 51 and 52 are stacked alternately starting from the first ring body 51, and finally the disc body 53 is stacked, so that the ring bodies 51 and 52 are stacked at the center of the stacked body. One end of the space formed is closed to form an introduction port 50a. Further, the second ring body 52 stacked between the first ring bodies 51 is provided with a passage space 54 passing through the second ring body 52 with an inner wall and an outer wall remaining in a part thereof. As a result, the gap formed between the inner surface of the first ring body 51 and the inner wall of the second ring body 52 becomes an introduction path 54a leading to the flow path space 54, and the gap formed between the inner surface of the first ring body 51 and the inner wall of the second ring body A gap formed between the outer wall 52 and the outer wall 52 serves as a lead-out path 54b leading to the outside. This lead-out path 54b forms a lead-out port 50b. With this configuration, the amount of differential pressure generated between the inlet 50a side and the outlet 50b side can be freely set by adjusting the number of stacked ring bodies 51, 52 and the range of the flow path space 54. It is now possible to do so.

The flow rate control mechanism 30 is configured such that the valve opening degree can be adjusted using an actuator such as a piezo element.

Further, the flow rate control device MF1 includes a control unit 90 for performing a flow rate control function, a flow rate sensor diagnosis function, a pressure sensor diagnosis function, a flow rate control mechanism diagnosis function, and the like. The control unit 90 has a so-called computer equipped with a CPU, memory, A/D/D/A converter, input/output means, etc., and allows each device to cooperate by executing a program stored in the memory. to demonstrate each function. Note that an input/output means (not shown) is connected to the control section 90.

As shown in FIG. 2, the control unit 90 specifically includes a flow rate measurement unit 90a, a control value calculation unit 90b, a valve control unit 90c, an output-related value measurement unit 90d, a reference output-related value storage unit 90e, and a reference value. Storage unit 90f, correction unit 90g, deviation calculation unit 90h, flow rate sensor diagnosis unit 90i, pressure sensor diagnosis unit 90j, pressure sensor calibration unit 90k, flow rate control mechanism diagnosis unit 90l, initialization execution unit 90m, diagnosis result output unit 90n, It is equipped with

The flow rate measurement unit 90a calculates the flow rate value of the fluid based on the detected values (pressure values) detected by both pressure sensors 60 and 70 provided in the flow rate sensor 20. Note that the flow rate measuring section 90a is configured to receive the detection values detected by both the pressure sensors 60 and 70 at a predetermined timing.

The control value calculation unit 90b calculates a control value for feedback controlling the flow rate control mechanism 30 based on the deviation between the flow rate value calculated by the flow rate measuring unit 90a and a preset reference flow rate value.

The valve control unit 90c controls the opening degrees of the valves of the flow rate control mechanism 30 and the opening/closing valves UV and DV. Specifically, during normal operation, feedback control is performed to change the opening degree of the valve of the flow rate control mechanism 30 based on the control value calculated by the control value calculation unit 90b. Further, the valve control unit 90c completely closes the valve of the flow rate control function 30 and opens the on-off valves UV and DV based on the flow rate sensor diagnosis instruction inputted from the input/output means. Further, the valve control unit 90c completely closes the on-off valve UV and opens the valve of the flow rate control mechanism 30 and the on-off valve DV based on the pressure sensor diagnosis instruction inputted from the input/output means. Further, the valve control unit 90c completely closes the valve of the flow control mechanism 30 and opens the on-off valves UV and DV based on the flow control mechanism diagnosis instruction inputted from the input/output means.

The output-related value measurement unit 90d measures the volume value of the fluid (output-related value) based on the detected values (pressure value, temperature value) detected by both pressure sensors 60, 70 and temperature sensor 80 provided in the flow rate sensor 20. is calculated. Note that the output-related value measuring section 90d starts measuring the output-related value based on the input of the flow rate sensor diagnosis instruction from the input/output means. Specifically, when a flow rate sensor diagnosis instruction is input from the input/output means, the valve control unit 90c completely closes the valve of the flow rate control function 30 and opens the on-off valves UV and DV. Then, the downstream side of the flow rate control mechanism 30 begins to be depressurized by a discharge mechanism (not shown) provided downstream, for example, an exhaust pump connected to the film forming chamber. Then, by integrating the mass flow rate Q of the fluid calculated using the above equation (1) from the pressure values P1 and P2 measured by the pressure sensors 60 and 70 over a predetermined time, the mass flow rate integral value n is obtained. calculate. Subsequently, at the start and end of a predetermined period of time, the measured volume value V is calculated using equation (4) from the pressure difference ΔP of the pressure measured by the upstream pressure sensor 60 and the temperature value T measured by the temperature sensor 80. Calculate. Note that the measured volume value V indicates the flow path volume from the flow rate control mechanism 30 to the inlet 50a of the resistor 50. Note that the output-related value measuring section 90d is configured to receive the detection values detected by both the pressure sensors 60, 70 and the temperature sensor 80 at a predetermined timing.

The reference output related value storage unit 90e stores information that has been measured under predetermined measurement ambient conditions before the flow rate control device MF1 is shipped from the manufacturing factory, or after the flow rate control device MF1 is actually connected to semiconductor manufacturing equipment, etc. It stores reference data that associates the reference volume value _VS with its measurement surrounding conditions.

The reference value storage section 90f stores reference values for determining whether the measured volume value V is normal. Note that the reference value is determined based on the reference volume value _VS. In this embodiment, a threshold value is set for the ratio of deviation of the measured volume value V with respect to the reference volume value _VS , and by determining whether the ratio of deviation exceeds the threshold value, the measured volume value V is determined to be normal. I am determining whether it is. Therefore, the threshold value of the deviation ratio becomes the reference value.

The correction unit 90g generates measurement data by associating the measured volume value V with the measurement ambient conditions at the time of measuring the measured volume value V, and generates measurement data by associating the measured volume value V with the measurement ambient conditions included in the measurement data and the measurement ambient conditions included in the reference data. The measured volume value V or the reference value is corrected based on the deviation from the conditions. In this embodiment, the threshold value that is the upper limit of the ratio of deviation of the measured volume value V with respect to the reference volume value _VS is corrected.

The deviation calculation unit 90h calculates the ratio of deviation of the measured volume value V with respect to the reference volume value _VS.

The flow rate sensor diagnosis unit 90i diagnoses the function of the flow rate sensor 20 by determining whether or not the measured volume value V is normal based on the measured volume value V based on the correction result of the correction unit 90g and the reference value. It is something.

The pressure sensor diagnosis section 90j diagnoses whether the pressure values detected by both pressure sensors 60, 70 provided in the flow rate sensor 20 are within a predetermined pressure range. Specifically, when a pressure sensor diagnosis instruction is input from the input/output means, the valve control unit 90c completely closes the on-off valve UV and opens the valve of the flow rate control mechanism 30 and the on-off valve DV. Then, the pressure on the downstream side of the flow rate control mechanism 30 begins to be reduced by the discharge mechanism provided on the downstream side. In this pressure sensor diagnostic state, it is diagnosed whether both pressure sensors 60, 70 are within a specified pressure range.

The pressure sensor calibration unit 90k performs zero point correction of both pressure sensors 60 and 70 provided in the flow rate sensor 20. Specifically, in the pressure sensor diagnosis state, when a pressure sensor calibration instruction is input from the input/output means, the zero points of both pressure sensors 60 and 70 are corrected.

The flow rate control mechanism diagnosis section 90l diagnoses the flow rate control mechanism 30. Specifically, when a flow control mechanism diagnosis instruction is input from the input/output means, the valve control unit 90c completely closes the valve of the flow control mechanism 30 and opens the on-off valves UV and DV. Then, the pressure on the upstream side of the flow rate control mechanism 30 starts to be increased by the supply mechanism provided on the upstream side, and the pressure on the downstream side of the flow rate control mechanism 30 starts to be reduced by the discharge mechanism provided on the downstream side. Then, it is determined whether the rate of increase in the flow rate value measured by the flow rate measuring section 90a is within a specified rate of increase range.

The initialization execution section 90m resets the reference data stored in the reference output related value storage section 90e. Specifically, when an initialization instruction is input from the input/output means, the reference data stored in the reference output-related value storage section 90e is converted into a reference volume value V _S obtained by re-measuring the reference data under different measurement ambient conditions. ' and the measurement ambient conditions are overwritten with new reference data, and further, the reference value stored in the reference value storage section 90f is reset based on the reference data.

The diagnosis result output section 90n outputs the diagnosis results of each diagnosis section through an input/output means in the form of images, sounds, or the like.

Next, a process for diagnosing the flow rate sensor 20 in the flow rate control device according to this embodiment will be described based on FIG. 6.

First, when a flow rate sensor diagnosis instruction is input from the input/output means, before starting the diagnosis, if the pressure measured by the upstream pressure sensor 60 is lower than the starting pressure (at P1 _START ), the Increase the pressure so that it is also high.

Next, the valve control unit 90c completely closes the valves of the flow rate control mechanism 30 that is exhibiting the flow rate control function based on the flow rate sensor diagnosis instruction, and opens the on-off valves UV and DV (step S101).

When the valve of the flow rate control mechanism 30 is completely closed, the downstream side of the flow rate control device MF1 is sucked and depressurized by the exhaust pump, and the pressure in the flow path changes over time.

Next, the output-related value measuring unit 90d calculates the mass flow rate Q from the pressure values detected by the pressure sensors 60 and 70 using the equation (1) (step S102), and then calculates the mass flow rate Q. A mass flow rate integral value n is calculated by time-integrating over a predetermined period of time (step S103). Further, at the start and end of the predetermined period, a pressure change amount ΔP1 is calculated based on the pressure value detected by the upstream pressure sensor 60, and a temperature value T detected by the temperature sensor 80 is obtained (step S104 ). Then, the measured volume value V is calculated from the mass flow rate integral value n, the pressure change amount ΔP, and the temperature value T using equation (4) (step S105). Note that from this series of calculations, it can be said that the mass flow rate integral value n is a value based on the pressure integral value.

Next, the correction unit 90g generates measurement data in which the measured volume value V is associated with the measurement ambient conditions at the time of measurement of the measured volume value V (step S106). Then, with reference to the reference data and measurement data, the deviation between the measurement ambient conditions of the reference data and the measurement ambient conditions of the measurement data is calculated, the deviation of the measurement ambient conditions is taken into account, and the measurement volume is calculated with respect to the reference volume value _VS. The threshold value that determines the upper limit of the deviation ratio of the value V is corrected (step S107). This corrects the reference value.

Finally, the deviation calculation unit 90h calculates the ratio of deviation of the measured volume value V with respect to the reference volume value _VS (step S108), and the flow rate sensor diagnosis unit 90i determines whether the deviation ratio exceeds the corrected threshold value. It is determined whether there is one (step S109). Then, the diagnostic result output unit 90n notifies that the function of the flow rate sensor 20 is normal and can be continued to be used if the threshold value is not exceeded (step S110), and if the threshold value is exceeded, , notifies that there is an abnormality in the function of the flow rate sensor 20 (step S111).

As a result of diagnosing the flow rate sensor 20, if it is determined that the flow rate sensor 20 is normal, the flow control function is returned to.On the other hand, if it is determined that the flow rate sensor 20 is abnormal, the flow rate control function is returned to. Then, a diagnostic process for the pressure sensors 60 and 70 is performed.

In the flow sensor diagnosis step, each parameter (specifically, pressure change amount ΔP, temperature value T, mass flow rate integral value n, etc.) is substituted into equation (4) derived using the state equation. By doing so, the volume value V (internal volume) is calculated, and the volume value V is used to diagnose whether or not there is an abnormality in the function of the flow sensor. It has been found that parameters that do not appear in the equation also affect the calculation of the volume value V.

Specifically, when the step S101 is executed, if the pressure on the downstream side of the resistor 50, in other words, the secondary pressure of the flow control device MF increases, this causes the pressure on the upstream and downstream sides of the resistor 50 to increase. The differential pressure between the Along with this, the pressure drop time becomes shorter, and as a result, the integration time (predetermined time) of the mass flow rate integral value n becomes shorter, and the number of samplings of the mass flow rate Q for calculating the mass flow rate integral value n decreases. This makes it easy for errors to occur in the volume value V. It was also found that this error in the volume value V affects the accuracy of diagnosis of the flow rate sensor.

Therefore, when the differential pressure generated between the upstream and downstream sides of the fluid becomes less than a predetermined value, the measured output-related value is corrected (increased) or the reference value is decreased (decreased). ) By providing a correction unit (diagnosis standard correction unit) that performs correction, the diagnostic criteria for the flow rate sensor 20 is made stricter, thereby preventing damage to the entire system in which the device is incorporated due to a misdiagnosis of the flow rate control device MF. It can be prevented. Note that this correction may be performed by the correction section 90g, or may be performed by providing a correction section (diagnostic standard correction section) separate from the correction section 90g.

Next, a process for diagnosing the pressure sensor in the flow rate control device according to this embodiment will be explained based on FIG.

When the flow rate sensor 20 is diagnosed as having an abnormality, when a pressure sensor diagnosis instruction is input from the input/output means, the valve control section 90c completely closes the opening/closing valve UV based on the instruction, and The valve of the flow rate control mechanism 30 and the opening/closing valve DV are opened (step S201). Next, the pressure sensor diagnosis unit 90j diagnoses whether the pressure values measured by both pressure sensors 60, 70 are within a specified pressure range (step S202). Then, the diagnosis result output unit 90n notifies that the pressure sensors 60, 70 are normal when the pressure is within the specified pressure range (step S203), and when the pressure sensor 60, 70 is not within the specified pressure range. is abnormal (step S204).

Note that if the pressure sensors 60 and 70 are diagnosed to be normal, a diagnosis process for the flow rate control mechanism 30, which will be described later, is subsequently performed. On the other hand, when the pressure sensors 60 and 70 are diagnosed as having an abnormality, when a pressure sensor calibration instruction is input from the input/output means, the pressure sensor calibration section 90k causes the pressure sensors 60 and 70 to perform measurements. When the pressure value becomes equal to or less than a predetermined pressure value, zero point correction of both pressure sensors 60 and 70 is performed (step S205). Subsequently, the flow rate sensor 20 is diagnosed again (step S206). When the diagnosis result output unit 90n diagnoses that the flow rate sensor 20 is normal, it notifies the flow rate sensor 20 to that effect, and then returns to the flow rate control function (step S207). On the other hand, if it is diagnosed that there is an abnormality in the flow rate sensor 20, it is notified that there is an abnormality in the pressure sensors 60, 70 that requires repair (step S208).

Next, a diagnosis process for the flow rate control mechanism 30 in the flow rate control device MF1 according to the present embodiment will be described based on FIG. 8.

First, when the flow rate sensor 20 is diagnosed to be abnormal and the pressure sensors 60 and 70 are diagnosed to be normal, when a flow rate control mechanism diagnosis instruction is input from the input/output means, the valve Based on the instruction, the control unit 90c completely closes the valve of the flow rate control mechanism 30 and opens the on-off valves UV and DV (step S301). Next, the flow control mechanism diagnosis section 90l diagnoses whether the rate of increase in the flow rate value measured by the flow rate measurement section 90a is within a specified increase rate range (step S302). When the diagnostic result output unit 90n is within the specified increase rate range, it notifies that the flow rate control mechanism 30 is normal (step S303).On the other hand, when it is not within the specified increase rate range, the flow control mechanism 30 is notified that the flow rate control mechanism 30 is normal. It is notified that there is an abnormality in the mechanism 30 that requires repair (step S304). There is a high possibility that this abnormality in the flow rate control mechanism 30 is a valve seat leak.

Note that if the flow rate control mechanism 30 is diagnosed to be normal, initialization is subsequently performed (step S305). In the initialization, when an initialization instruction is input from the input/output means, the initialization execution unit 90m measures the reference data stored in the reference output related value storage unit 90e again under different measurement ambient conditions. The reference volume value V _S ′ and its measurement ambient conditions are overwritten with new reference data that is associated with the reference volume value V S ′, and the threshold value stored in the reference value storage unit 90f is reset based on the new reference data. This makes it possible to continue using the flow control device MF without replacing it when the amount of leakage occurring in the valve of the flow control mechanism 30 is such that it does not interfere with the function of the flow control device MF. can. After that, the flow rate control function is restored.

Incidentally, after initializing the flow rate control device MF1, the flow rate sensor 20 is diagnosed again, and if it is diagnosed that there is an abnormality in the flow rate sensor 20, then the pressure sensors 60, 70 and the flow rate control mechanism 30 are removed. It can be determined that an abnormality has occurred in the function of the flow rate sensor 20 due to the following factors. Possible causes include clogging of the resistor 50, leakage of the flow path 10, and mismatch between the gas specifications of the flow rate control device MF1 and the actual gas.

Note that when the initialization is performed, the reference values are sequentially replaced with the initialized reference values, so the initialized reference values are different from the reference values first stored (set) in the reference value storage section 90f. a reference value change amount calculation unit that calculates the amount of change; a reference value change amount determination unit that determines whether the amount of change exceeds a predetermined amount of change; It is preferable to include a warning unit that notifies you when a problem occurs. Note that the predetermined amount of change is the upper limit of the amount of change in the reference value after initialization with respect to the initially set reference value, and this upper limit value is a pre-guaranteed valve seat leakage value for the flow rate control mechanism 30. It is possible to derive it based on the ratio of deviation of the output-related value with respect to the reference output-related value, which is calculated from the maximum value of the quantity. Furthermore, when initialization is performed multiple times, the total amount of change from the first stored reference value becomes the amount of change after initialization.

With this configuration, it is possible to sequentially diagnose each element of the flow rate control device MF1 that cannot be determined by diagnosing the flow rate sensor 20 alone, and it is possible to narrow down the factors that are the cause of the abnormality in the flow rate sensor 20. can. This reduces the possibility of overlooking abnormalities that can be corrected by calibration, repair, replacement, etc., and can reduce misdiagnosis.

In this embodiment, each instruction is input manually by the user through the input/output means, but a program that stores the timing of each instruction is stored in memory, and each instruction is automatically executed by that program. You can go there.

Further, in this embodiment, the flow rate sensor 20 is diagnosed after the pressure sensors 60 and 70 are calibrated, and the function of the flow rate sensor 20 is diagnosed. It is also possible to similarly diagnose and calibrate other sensors, etc. That is, a fluid sensor that measures fluid, an output value that is an output value of the fluid sensor, or an output-related value that is a value related thereto, is measured, and the measured output-related value is compared with a predetermined reference value to determine the fluid sensor. a diagnostic unit for diagnosing the function of the fluid sensor, and the diagnostic unit is configured to compare an output-related value measured after correcting some or all elements of the fluid sensor with a reference value. Just make it into something. Note that the fluid sensor is a flow sensor, and an element of the flow sensor includes either a pressure sensor or a temperature sensor. Further, in this case, the fluid sensor is a flow rate sensor, and further includes a flow rate control mechanism that controls the flow rate of the fluid by a valve based on a flow rate value measured by the flow rate sensor, and the valve of the flow rate control mechanism is closed. The configuration may be such that the pressure is reduced in the state, and the state of the valve of the flow rate control mechanism is diagnosed based on whether the rate of increase in the flow rate value measured by the flow rate sensor is within a specified rate of increase range.

Further, in the present embodiment, each valve is controlled by the valve control unit 90c included in the flow rate control device MF based on each instruction inputted from the input/output means, but the invention is not limited to this, and each valve is , the flow control device MF may be controlled by a valve control section provided in a control device provided outside the flow control device MF.

<Other embodiments>
As another embodiment, a flow rate control device MF2 shown in FIG. It is provided between the resistor 50 and the on-off valve 31. In such a flow control device MF2, ROR type diagnosis is possible. Specifically, when diagnosing the function of the flow rate sensor 20, if gas continues to be supplied with the on-off valve 31 closed, the pressure on the upstream side of the on-off valve 30 increases. Also in this case, since a pressure difference occurs between the upstream side and the downstream side of the resistor 50, the volume value V between the resistor 50 and the on-off valve 31 is determined based on the measured values of each sensor 60, 70, and 80. can be calculated, and the function of the flow rate sensor 20 can be diagnosed using this volume value V. In the present embodiment, it is necessary to change the reference value by taking into consideration changes in primary pressure and temperature caused by piping and external equipment connected upstream of the flow rate sensor 20 as measurement ambient conditions.

Further, as another embodiment, in particular, in the flow control device MF1 of the first embodiment, a differential pressure sensor that measures the differential pressure on the upstream side and the downstream side of the resistor 50 is provided in place of both pressure sensors 60 and 70. is possible. If such a sensor is used, it becomes possible to reduce the influence of the nozzle of the pressure sensor and reduce costs, and it becomes possible to use it even more preferably for fluids whose pressure fluctuates. In addition, in the case of the flow rate control device MF1 of Embodiment 1, since a chamber (vacuum) such as a film forming chamber is connected to the secondary side, the measurement of the differential pressure sensor is performed using this secondary side as a reference (zero). The primary side flow rate can be determined from the value.

In the embodiment described above, the diagnosis is made based on whether the ratio of deviation of the calculated volume value V with respect to the reference volume value _VS exceeds a threshold value, but the present invention is not limited to this, and the reference volume value Diagnosis may be made based on the deviation of the volume value V with respect to _VS. In this case, an upper limit value and/or a lower limit value may be set based on the reference output related value, and the upper limit value and/or lower limit value may be used as the reference value. Further, in the embodiment, the reference value is corrected based on the deviation between the measurement ambient conditions of the measurement data and the measurement ambient conditions of the reference data, but the output-related value of the measurement data may be corrected. Furthermore, in the embodiment, when calculating the volume value V, the amount of pressure change and the temperature value at the start and end of the predetermined time are used, but the amount of flow rate change may be used.

Further, in the embodiment, the pressure and temperature of the fluid are exemplified as measurement ambient conditions, but these conditions are not limited to these. For example, in the diagnosis as in the embodiment, the error in the volume value V In addition to the secondary pressure and temperature described above, possible measurement ambient conditions that may be factors include shifts in the reference points of each pressure sensor, clogging of resistors, and seat leak in the flow rate control mechanism. Therefore, the reference value may be corrected according to these measurement surrounding conditions.

Further, in the above embodiment, the temperature sensor is included in the flow rate sensor, but the flow rate sensor may be of any type as long as it has the necessary configuration to measure the flow rate. Sensors that are not directly involved do not necessarily need to be included in the flow rate sensor. Note that the temperature sensor may be provided separately from the flow rate sensor as a sensor necessary for measuring the measurement ambient conditions.

Note that the diagnostic system according to the present invention can be applied to a flow rate control device and a pressure control device as in the above embodiment, and can also be applied to a flow rate measuring device. Furthermore, the fluid sensor according to the present invention is not limited to the flow rate sensor used in the embodiments described above, but may also be a pressure sensor, a temperature sensor, or the like.

MF1 Flow rate control device UV, DV opening/closing valve 10 flow path 20 flow rate sensor 30 flow rate control mechanism 40 pressure sensor 50 resistor 60 upstream pressure sensor 70 downstream pressure sensor 80 temperature sensor 90 control unit 90e reference output related value storage unit 90g correction Section 90i Flow rate sensor diagnosis section

Claims (9)

a resistor, an upstream pressure sensor provided upstream of the resistor, a downstream pressure sensor provided downstream of the resistor, and a detection device of the upstream pressure sensor and the downstream pressure sensor. a flow rate measurement unit that calculates a fluid flow rate value based on each pressure value; a flow rate sensor that measures the fluid flow rate;
a first valve provided upstream of the upstream pressure sensor;
a flow path volume from the first valve to the resistor, the pressure of which is measured by the upstream pressure sensor;
a flow rate integral value obtained by time-integrating the flow rate output from the flow rate measuring section over a predetermined period during which a change occurs in the upstream pressure measured by the upstream side pressure sensor in the flow path volume; and the flow rate integral value. The size of the flow path volume is determined based on each pressure in the flow path volume measured by the upstream pressure sensor at the start and end points of time integration, and the state equation of the gas that targets the flow path volume. an output-related value measuring unit that measures a measured volume value indicating the
a reference value storage unit that stores a threshold value determined based on a reference volume value measured under predetermined measurement ambient conditions for the channel volume in order to determine whether or not the measured volume value is normal;
At least one of the measured volume value or the threshold value is corrected according to a downstream pressure measured by the downstream pressure sensor on the downstream side of the flow path volume between the first valve and the resistor. a correction section;
a diagnosis unit that diagnoses the flow rate sensor based on the measured volume value and the threshold value, at least one of which has been corrected by the correction unit,
The correction unit adjusts the measured volume value when the differential pressure between the downstream pressure and the upstream pressure is equal to or less than a predetermined value after the output-related value measurement unit measures the measured volume value. A diagnostic system characterized in that the diagnostic system is configured to perform a correction to increase the reference value or to perform a correction to decrease the reference value . further comprising a reference output-related value storage unit that stores at least the reference volume value measured under reference measurement ambient conditions and the downstream pressure measured by the downstream pressure sensor included in the measurement ambient conditions in association with each other; Equipped with
The correction unit adjusts at least one of the measured volume value or the threshold value to the downstream pressure measured by the downstream pressure sensor that is at least one of the measurement ambient conditions associated with the measured volume value and the reference volume. 2. The diagnostic system of claim 1, wherein the correction is based on a deviation from a downstream pressure associated with the value. The diagnostic system according to claim 1, wherein the flow rate integral value is a mass flow rate integral value obtained by integrating the mass flow rate calculated based on the pressure on the upstream side and the pressure on the downstream side of the resistor over the predetermined period. The measured volume value includes the amount of pressure change measured by the upstream pressure sensor at the start and end of the predetermined period, the temperature of the fluid or the amount of temperature change during the predetermined period, and the mass flow integral value. 4. The diagnostic system according to claim 3, wherein the fluid volume value is calculated from. further comprising a second valve provided downstream of the resistor and capable of blocking the flow of the fluid;
5. The diagnostic system according to claim 4, wherein the pressure of the fluid in the channel volume changes over time by blocking the flow of the fluid. When the differential pressure between the upstream pressure measured by the upstream pressure sensor and the downstream pressure measured by the downstream pressure sensor becomes a predetermined value or less, the correction unit makes a correction to increase the measured volume value. 2. The diagnostic system according to claim 1, wherein the diagnostic system performs correction to reduce the threshold value. a resistor, an upstream pressure sensor provided upstream of the resistor, a downstream pressure sensor provided downstream of the resistor, and a detection device of the upstream pressure sensor and the downstream pressure sensor. a flow rate measurement unit that calculates a fluid flow rate value based on each pressure value; a flow rate sensor that measures the fluid flow rate; and a first valve provided upstream of the upstream pressure sensor; A diagnostic method for diagnosing the function of a flow rate sensor in a flow rate control device including a flow path volume from the first valve to the resistor, the pressure of which is measured by the upstream side pressure sensor,
a flow rate integral value obtained by time-integrating the flow rate output from the flow rate measuring section over a predetermined period during which a change occurs in the upstream pressure measured by the upstream side pressure sensor in the flow path volume; and the flow rate integral value. The size of the flow path volume is determined based on each pressure in the flow path volume measured by the upstream pressure sensor at the start and end points of time integration, and the state equation of the gas that targets the flow path volume. Measure the measured volume value that indicates the
Setting a threshold value determined based on a reference volume value measured under predetermined measurement ambient conditions for the flow path volume as a reference value in order to determine whether the measured volume value is normal;
Correcting at least one of the measured volume value or the threshold value according to the downstream pressure measured by the downstream pressure sensor, which is the pressure of the downstream volume of the flow path volume,
diagnosing the flow rate sensor based on the measured volume value and the threshold value, at least one of which has been corrected;
After measuring the measured volume value , if the differential pressure between the downstream pressure and the upstream pressure is less than or equal to a predetermined value, a correction is performed to increase the measured volume value , or the reference value is A method for diagnosing a flow rate sensor, the method comprising making a correction to reduce the amount of . a resistor, an upstream pressure sensor provided upstream of the resistor, a downstream pressure sensor provided downstream of the resistor, and a detection device of the upstream pressure sensor and the downstream pressure sensor. a flow rate measurement unit that calculates a fluid flow rate value based on each pressure value; a flow rate sensor that measures the fluid flow rate; and a first valve provided upstream of the upstream pressure sensor; A program for use in a diagnostic system comprising: a flow path volume from the first valve to the resistor, the pressure of which is measured by the upstream pressure sensor;
a flow rate integral value obtained by time-integrating the flow rate output from the flow rate measuring section over a predetermined period during which a change occurs in the upstream pressure measured by the upstream side pressure sensor in the flow path volume; and the flow rate integral value. The size of the flow path volume is determined based on each pressure in the flow path volume measured by the upstream pressure sensor at the start and end points of time integration, and the state equation of the gas that targets the flow path volume. an output-related value measuring unit that measures a measured volume value indicating the
a reference value storage unit that stores a threshold value determined based on a reference volume value measured under predetermined measurement ambient conditions for the channel volume in order to determine whether or not the measured volume value is normal;
At least one of the measured volume value or the threshold value is corrected according to a downstream pressure measured by the downstream pressure sensor on the downstream side of the flow path volume between the first valve and the resistor. Allows the computer to function as a correction section,
The correction unit adjusts the measured volume value when the differential pressure between the downstream pressure and the upstream pressure is equal to or less than a predetermined value after the output-related value measurement unit measures the measured volume value. A program characterized in that the program is configured to perform a correction to increase the reference value or to perform a correction to decrease the reference value . A diagnostic system according to claim 1, 2, 3, 4 , 5 or 6 ,
A flow control device comprising: a valve control section that controls the first valve.