Mass Flow Controller with Advanced Backflow Diagnostics

Abstract

A diagnostic system includes a controller for controlling the operation of a mass flow controller. The controller is communicatively coupled to a valve and at least one sensor and is adjusted to control the valve based on a predetermined set point value and communication from the at least one sensor. The controller determines at least one predetermined value associated with a reverse flow of a fluid and causes the controller to enter a hard fault or safe state. The predetermined value of the flow is a certain percentage of the total flow or a certain percentage of the total flow over a period of time. The controller can record a date, time, and a device identifier in response to determining the at least one predetermined value. In addition, the diagnostic system can include a central controller configured to receive diagnostic data from multiple controllers and control the operation of these controllers.

Description

Background Art

[0001] Many industrial processes require precise control of various process fluids. For example, in the semiconductor industry, mass flow meters (MFMs) are used to accurately measure the amount of process fluid introduced into a process chamber. In addition to measuring mass flow, mass flow controllers (MFCs) are also used to accurately measure and control the amount of process fluid introduced into a process chamber. It will be understood that, as used herein, the term "fluid" applies to any type of gas or vapor for which controlled flow may be of interest.

[0002] These devices need to be maintained to maintain acceptable performance levels. Maintenance of these devices must be timely and requires advanced knowledge of the device's operation, so maintenance costs can be high. Many MFCs have self-diagnostic capabilities based on built-in hardware with limited capabilities. The limited capabilities and complex design of existing MFC diagnostic systems only increase the cost of MFCs. Summary of the invention

[0003] MFCs that are regulated to control specific types of fluids under known conditions (i.e., pressure, volume, and temperature) may often become regulated failures during installation, maintenance, and testing. In addition, MFCs may become regulated failures due to unknown operating conditions or simply due to use (i.e., wear and tear). In summary, the regulation failure of MFCs can be determined by understanding normal and abnormal MFC variation behaviors and taking action on the problem before the identified problem affects the associated operation (e.g., the output in the manufacturing supply chain). In this way, advanced MFC diagnostic systems can improve the operation of the manufacturing supply chain. However, without careful consideration, the design and development of systems for solving these problems may be complex and very expensive.

[0004] An advanced diagnostic system for calibrating and controlling the operation of a previously adjusted MFC is disclosed herein. The diagnostic system monitors selected variables (e.g., adjustments to set point values ​​and reverse flow rate), generates notifications when problems are detected, and can cause the MFC to be calibrated and shut down. The diagnostic system can re-adjust the MFC based on one or more modified adjustment variables (e.g., set point, temperature, pressure, and volume). In addition, if the reverse flow rate reaches an undesirable level, the diagnostic system can shut down the MFC. In addition, the advanced diagnostic system can be designed and developed entirely in software (e.g., firmware) or a combination of hardware and software. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Illustrative embodiments of the subject matter of the present disclosure are described in detail below with reference to the accompanying drawings which are incorporated herein by reference, in which:

[0006] Figure 1 illustrates a mass flow controller with control and advanced diagnostic electronics according to certain example embodiments;

[0007] FIG. 2A to FIG. 2B a diagram illustrating an algorithm for diagnosing and controlling the operation of a mass flow controller according to certain example embodiments; and

[0008] Figure 3 is a block diagram depicting computing machines and system applications, according to some example embodiments. DETAILED DESCRIPTION

[0009] Although the manufacture and use of various embodiments of the present disclosure are discussed in detail below, it should be understood that the present disclosure provides many applicable innovative concepts that can be embodied in many specific contexts. The specific embodiments discussed herein are illustrative only and do not limit the scope of the present disclosure. For the sake of clarity, all features of the actual implementation may not be described in the present disclosure. Of course, it should be understood that in the development of any such actual embodiment, many decisions specifically for the implementation must be made to achieve the specific goals of the developers, such as complying with system-related constraints and business-related constraints, which will vary depending on the implementation. In addition, it should be understood that such development work may be complex and time-consuming, but it will be a routine task for those of ordinary skill in the art who benefit from the present disclosure.

[0010] As used herein, adjustment refers to an MFC that has been adjusted (e.g., adjusted in a laboratory or MFC manufacturing facility) before being put into use. As used herein, calibration refers to an MFC controller that is executed to adjust a control variable to reflect any changes from when the MFC is adjusted to when it is in operation, or during the MFC operation process. A set point is a variable that includes an identifier and a value. A set point is a desired flow rate, and is set based on known factors (e.g., fluid type, pressure, volume, and temperature) during the adjustment phase. During MFC operation, the set point can be adjusted multiple times to, for example, correct for slight drifts caused by the normal operation of the MFC. As will be discussed later, the number of times adjusted can reflect several problems of the MFC, or more specifically, can reflect several problems of the adjustment variables of the MFC. As used herein, reverse flow rate refers to the flow rate of a fluid in the direction of a return fluid source. As an example, a fluid used in a manufacturing process (e.g., the manufacture of semiconductor devices) travels from an upstream source to a downstream processing chamber. In this example, reverse flow rate relates to a fluid traveling in the direction of a return upstream source.

[0011] Figure 1An example of a thermal mass flow controller (MFC) 100 according to the disclosed embodiments but which may include other types of mass flow sensing methods is illustrated. The mass flow controller 100 includes a block 110, which is a platform on which the components of the MFC 100 are mounted. A thermal mass flow meter 140 and a valve assembly 150 including a control valve 170 are mounted on the block 110 between a fluid inlet 120 and a fluid outlet 130. The thermal mass flow meter 140 includes a flow divider 142, through which a majority of the fluid typically flows, and a smaller portion of the fluid flows, and a thermal flow sensor 146. The flow divider 142 is adjusted using known fluids to determine the appropriate relationship between the fluid flowing in the mass flow sensor and the fluid flowing in the flow divider 142 at various known flow rates, so that the total flow through the flow meter can be determined from the thermal flow sensor output signal. The thermal flow sensor 146 and the flow divider 142 can then be mated to the control valve 170 and the control and diagnostic and controller 160, and then adjusted again under known conditions. The responses of the control and diagnostics and controller 160 and control valve 170 are then summarized so that the overall response of the system to a change in set point or input pressure is known and can be used to control the system to provide the desired response. Other functions of the control and diagnostics and controller 160 include advanced diagnostic features related to zero trending, zero recommendations, poor zero determination, excessive zero drift, and regurgitation, as will be described with respect to FIGS. 2 and 3. Figure 3 discussed in more detail.

[0012] The thermal flow sensor 146 is contained within the sensor housing 102 (a portion of the sensor housing is removed in the figure to show the thermal flow sensor 146), which is mounted on the mounting plate 108. The thermal flow sensor 146 is a small diameter tube (commonly referred to as a capillary tube) having a sensor inlet portion 146A, a sensor outlet portion 146B, and a sensor measurement portion 146C around which two resistive coils or windings 147, 148 are arranged. In operation, current is provided to the two resistive windings 147, 148, which are in thermal contact with the sensor measurement portion 146C. The current in the resistive windings 147, 148 heats the fluid flowing in the measurement portion 146C to a higher temperature than the temperature of the fluid flowing through the flow divider 142. The resistance of the windings 147, 148 varies with temperature. As the fluid flows through the sensor conduit, heat is transferred from the upstream resistor 147 toward the downstream resistor 148, where the temperature difference is proportional to the mass flow rate through the sensor.

[0013] An electrical signal related to the flow rate of the fluid through the sensor is derived from the two resistor windings 147, 148. The electrical signal may be derived in a number of different ways, such as from the difference in resistance of the multiple resistor windings or from the difference in energy provided to each resistor winding to maintain each winding at a particular temperature. Examples of various ways in which an electrical signal associated with the flow rate of a fluid in a thermal mass flow meter may be determined are described, for example, in commonly owned U.S. Patent No. 6,845,659, which is incorporated herein by reference. The electrical signal derived from the resistor windings 147, 148 comprises the sensor output signal after signal processing.

[0014] The sensor output signal is correlated with the mass flow rate in the mass flow meter so that the fluid flow rate can be determined when the electrical signal is measured. Typically, the sensor output signal is first correlated with the flow rate in the sensor 146, and then the sensor output signal is correlated with the mass flow rate in the diverter 142 so that the total flow through the flow meter can be determined and the control valve 170 can be controlled accordingly. The correlation between the sensor output signal and the fluid flow rate is complex and depends on multiple operating conditions, including fluid type, flow rate, inlet and / or outlet pressure, temperature, etc.

[0015] The process of associating the raw sensor output with the fluid flow rate requires adjusting and / or calibrating the mass flow controller. For example, the mass flow sensor can be adjusted by passing a known amount of known fluid through the sensor portion and adjusting specific signal processing parameters to provide a response that accurately represents the fluid flow rate. For example, the output can be normalized so that the specified voltage range (e.g., 0V to 5V) of the sensor output corresponds to a flow rate range from zero to the upper limit of the sensor flow rate range. The output can also be linearized so that the change in the sensor output corresponds linearly to the change in flow rate. For example, if the output is linearized, the doubling of the fluid output will cause the doubling of the electrical output. Determine the dynamic response of the sensor, that is, determine the inaccurate effects of the pressure or flow rate changes generated when the flow or pressure changes so that such effects can be compensated. Diagnosis can also be performed on the sensor to determine whether the sensor needs maintenance or other aspects of the MFC need attention or maintenance.

[0016] The operation of a mass flow controller is typically degraded when the type of fluid used by the end user is different from the type of fluid used for adjustment and / or calibration, or when the operating conditions used by the end user (e.g., inlet and outlet pressures, temperature, flow rate range, etc.) are different from the operating conditions used when adjusting and / or calibrating. To this end, the flow meter can be adjusted or calibrated using additional fluids (referred to as "substitute fluids") and / or operating conditions, wherein any changes required to provide a satisfactory response are stored in a lookup table. U.S. Patent No. 7,272,512, "Flow Sensor Signal Conversion," filed by Wang et al., which is owned by the assignee of the present invention and incorporated herein by reference, describes a system in which the characteristics of different gases are used to adjust the response without requiring substitute fluids to calibrate the device for each different process fluid used.

[0017] In addition, the mass flow controller 100 can include a pressure transducer 112 coupled to the flow path at a location (typically but not limited to upstream of the flow divider 142) to measure the pressure in the flow path. The pressure transducer 112 provides a pressure signal indicative of the pressure. According to the disclosed embodiments, the pressure transducer 112 is used to measure the pressure during the flow measurement.

[0018] The diagnostic and controller 160 controls the position of the control valve 170 based on a set point indicating a desired mass flow rate and an electric current signal from a mass flow sensor, which indicates the actual mass flow rate of the fluid flowing in the sensor conduit. Then, conventional feedback control methods (such as proportional control, integral control, proportional-integral (PI) control, differential control, proportional-differential (PD) control, integral-differential (ID) control, and proportional-integral-differential (PID) control) can be used in the mass flow controller to control the fluid flow rate. A control signal (e.g., a control valve drive signal) is generated based on an error signal, which is the difference between a set point signal indicating a desired fluid mass flow rate and a feedback signal related to the actual mass flow rate sensed by the mass flow sensor. The control valve is positioned in the main fluid flow path (usually downstream of the flow divider and the mass flow sensor) and can be controlled (e.g., opened or closed) to change the mass flow rate of the fluid flowing through the main fluid flow path, the control being provided by the mass flow controller 100.

[0019] In the illustrated example, the flow rate is supplied as a voltage signal by electrical conductor 158 to the closed loop system and diagnostic and controller 160. The signal is amplified, processed, and supplied to the control valve assembly 150 using electrical conductor 159 to modify the flow rate. To this end, the controller 160 compares the signal from the mass flow sensor 140 with a predetermined value and adjusts the control valve 170 accordingly to obtain the desired flow rate. The control valve 170 can be a piezoelectric valve or other technology valve and is configured to operate at a flow rate greater than or equal to two standard liters per minute.

[0020] Reference now FIG. 2A to FIG. 2B , a diagram illustrating an algorithm for diagnosing and controlling the operation of the MFC 100 according to an example embodiment. Figure 2AIt is a diagram of an algorithm for locally diagnosing and controlling the operation of MFC 100. At box 200, monitoring selected variables (i.e., MFC process variables and control variables). Process variables may include measured pressure, temperature, volume, and flow rate of fluid. Control variables may include known variables, such as set point, set point adjustment times, temperature, volume, fluid type, flow rate, and predetermined variables. The set point variable is the measured flow rate. The predetermined variable may be a plurality of desired set points, set point adjustment times, reverse flow, and reverse flow rate. The desired set point and the desired flow rate are based on known fluid type, pressure, temperature, direction, and volume. The set point adjustment times are the number of adjustments made by controller 160. At box 202, the set point adjustment times are determined. During the normal operation process of MFC 100, the fluid flow rate may deviate from the desired set point. At box 204, the set point adjustment times are compared with at least one predetermined number. This comparison can be performed between the total number of adjustments according to the total gas hour, for example, according to 128 adjustments of the total gas. This information helps to understand the structure and stability of MFC 100 before performing the actual calibration check. For example, zero adjustment or 128 adjustments can indicate potential problems. Zero adjustment can indicate that the system protocol is not followed, the MFC 100 that is not installed correctly, the MFC 100 that accumulates or drifts, which may potentially mean that the MFC is not working. For example, 128 adjustments can indicate the deviation of MFC 100 component degradation and / or operating conditions. Any of the above situations can cause diagnosis or health checks and possible calibration. At frame 206, a notification message is generated. The notification message may include at least one of the following: temperature, valve drive, set point, sensor flow rate, gas flow hours, time, fluid type, and at least one value of the remaining set point adjustment number based on the total fluid hours. At frame 208, variables or selected variables are calibrated based on specific situations. Calibration may only require resetting the desired set point. However, it may also be necessary to partially or completely re-adjust MFC 100 based on partially or completely different known variable settings. Calibration is performed at least in part based on a predetermined number of set point value adjustments, a comparison result, and one of a user input. Other variables may also be monitored. At box 210, reverse fluid flow may be monitored. If the reverse flow exceeds a predetermined value (e.g., a certain percentage of the total flow or a certain percentage of the total flow over a period of time), the operation of the MFC 100 is controlled (box 212). In this case, the algorithm may force the MFC 100 to enter a hard fault or safe state. At box 214, the event is recorded. The recorded information may include the date, time, and device identifier. Although boxes 208 and 214 are described as being performed locally in this embodiment, it should be understood that the calibration commands may also be executed remotely and the recording system may be designed to store the recorded data remotely. Now refer to Figure 2B , illustrates a diagram of an algorithm for processing diagnostic or logged data and controlling the diagnostic and controller 160 from a central controller (e.g., a programmable logic controller (PLC) or a distributed control system (DCS)). At box 216, the central controller receives notification messages and / or logged data from multiple MFCs 100. Process engineers can take action based on this information. At box 218, the MFCs 100 and the diagnostic and controller 160 can be calibrated or their operation controlled.

[0021] As used herein, the term "hard fault" means that the MFC 100 is inoperable, for example due to liquid in a sensor that may affect the MFC's ability to detect temperature changes. A safe state is a software or hardware setting that forces the MFC 100 into a predetermined valve state. The safe state is used during startup and recovery for process and tool alarms.

[0022] Now refer to Figure 3 , illustrates a computing machine 300 and a system application module 400 according to an example embodiment. The computing machine 300 may correspond to any of the various computers, mobile devices, laptops, servers, embedded systems, or computing systems given herein. The module 400 may include one or more hardware or software elements, such as other OS applications and user and kernel space applications, which are designed to facilitate the computing machine 300 to perform the various methods and processing functions given herein. The computing machine 300 may include various internal or peripheral components, such as a processor 310, a system bus 320, a system memory 330, a storage medium 340, an input / output interface 350, a network interface 360 ​​for communicating with a network 370 (e.g., local loop, cellular / GPS, Bluetooth, WiFi), and a series of sensors 380 (e.g., about Figure 1 any of the identified sensors).

[0023] The computing machine can be implemented as a conventional computer system, an embedded controller, a laptop computer, a server, a mobile device, a smart phone, a wearable computer, a custom machine, any other hardware platform, or any combination or composite thereof. The computing machine can be a distributed system configured to function using multiple computing machines interconnected via a data network or bus system.

[0024] Processor 310 can be designed to execute code instructions to perform operations and functions described herein, manage request streams and address mappings, and is designed to perform calculations and generate commands. Processor 310 can be configured to monitor and control the operation of components in a computing machine. Processor 310 can be a general-purpose processor, a processor core, a multiprocessor, a reconfigurable processor, a microcontroller, a digital signal processor ("DSP"), an application-specific integrated circuit ("ASIC"), a controller, a state machine, a gated logic, a discrete hardware component, any other processing unit, or any combination or compound thereof. Processor 310 can be a single processing unit, multiple processing units, a single processing core, multiple processing cores, a dedicated processing core, a coprocessor, or any combination thereof. According to some embodiments, processor 310 and other components of computing machine 300 can be software-based or hardware-based virtualized computing machines executed in one or more other computing machines.

[0025] System memory 330 may include non-volatile memory, such as read-only memory ("ROM"), programmable read-only memory ("PROM"), erasable programmable read-only memory ("EPROM"), flash memory, or any other device capable of storing program instructions or data with or without the application of power. System memory 330 may also include volatile memory, such as random access memory ("RAM"), static random access memory ("SRAM"), dynamic random access memory ("DRAM"), and synchronous dynamic random access memory ("SDRAM"). Other types of RAM may also be used to implement system memory 330. System memory 330 may be implemented using a single memory module or multiple memory modules. Although system memory 330 is depicted as part of a computing machine, those skilled in the art will recognize that system memory 330 may be separate from computing machine 300 without departing from the scope of the subject technology. It should also be understood that system memory 330 may include or operate in conjunction with non-volatile storage devices such as storage media 340.

[0026] Storage medium 340 may include a hard disk, a floppy disk, a compact disk read only memory ("CD-ROM"), a digital versatile disk ("DVD"), a Blu-ray disk, a magnetic tape, a flash memory, other non-volatile storage devices, a solid state drive ("SSD"), any magnetic storage device, any optical storage device, any electrical storage device, any semiconductor storage device, any physically based storage device, any other data storage device, or any combination or composite thereof. Storage medium 340 may store one or more operating systems, application programs and program modules, data, or any other information. Storage medium 340 may be part of or connected to a computing machine. Storage medium 340 may also be part of one or more other computing machines that communicate with the computing machine (such as a server, a database server, a cloud storage device, a network attached storage device, etc.).

[0027] Application module 400 and other OS application modules may include one or more hardware or software elements, which are configured to facilitate the computing machine to perform various methods and processing functions given herein. Application module 400 and other OS application modules may include one or more algorithms or instruction sequences stored as software or firmware associated with system memory 330, storage medium 340 or both. Therefore, storage medium 340 may represent an example of a machine or computer readable medium, on which instructions or codes for execution by processor 310 may be stored. Machine or computer readable medium may generally refer to any one or more media for providing instructions to processor 310. Such machine or computer readable media associated with application module 400 and other OS application modules may include a computer software product. It should be understood that a computer software product including application module 400 and other OS application modules may also be associated with one or more processes or methods for transmitting application module 400 and other OS application modules to a computing machine via a network, any signal bearing medium, or any other communication or transmission technology. Application module 400 and other OS application modules may also include hardware circuits or information for configuring hardware circuits, such as microcode or configuration information for FPGA or other PLDs. In an exemplary embodiment, the application module 400 and other OS application modules may include algorithms capable of performing the functional operations described by the flowcharts and computer systems presented herein.

[0028] Input / output ("I / O") interface 350 may be configured to couple to one or more external devices to receive data from the one or more external devices and to send data to the one or more external devices. Such external devices and various internal devices may also be referred to as peripheral devices. I / O interface 350 may include both electrical and physical connections for coupling various peripheral devices to computing machine or processor 310. I / O interface 350 may be configured to transmit data, address and control signals between peripheral devices, computing machine or processor 310. I / O interface 350 may be configured to implement any standard interface, such as small computer system interface ("SCSI"), serial attached SCSI ("SAS"), fiber channel, peripheral component interconnect ("PCI"), PCI express (PCIe), serial bus, parallel bus, advanced technology attachment ("ATA"), serial ATA ("SATA"), universal serial bus ("USB"), Thunderbolt, FireWire, various video buses, etc. I / O interface 350 may be configured to implement only one interface or bus technology. Alternatively, I / O interface 350 may be configured to implement a variety of interface or bus technologies. I / O interface 350 may be configured to operate as part of, all of, or in conjunction with system bus 320. I / O interface 350 may include one or more buffers for buffering transmissions between one or more external devices, internal devices, computing machines, or processors 320.

[0029] I / O interface 320 can couple the computing machine to various input devices, including a mouse, a touch screen, a scanner, an electronic digitizer, a sensor, a receiver, a touch pad, a trackball, a camera, a microphone, a keyboard, any other pointing device, or any combination thereof. I / O interface 320 can couple the computing machine to various output devices, including a video display, a speaker, a printer, a projector, a tactile feedback device, an automation control, a robotic component, an actuator, a motor, a fan, a solenoid, a valve, a pump, a transmitter, a signal transmitter, a lamp, etc.

[0030] The computing machine 300 can operate in a networked environment using logical connections to one or more other systems or computing machines on the network through the NIC 360. The network may include a wide area network (WAN), a local area network (LAN), an intranet, the Internet, a wireless access network, a wired network, a mobile network, a telephone network, an optical network, or a combination thereof. The network may be a packet-switched network, a circuit-switched network of any topology, and any communication protocol may be used. The communication links within the network may involve various digital or analog communication media, such as fiber optic cables, free space optics, waveguides, electrical conductors, wireless links, antennas, radio frequency communications, etc.

[0031] The processor 310 may be connected to other elements of the computing machine or various peripheral devices discussed herein via a system bus 320. It should be understood that the system bus 320 may be internal to the processor 310, external to the processor 310, or both. According to some embodiments, any of the processor 310, other elements of the computing machine, or various peripheral devices discussed herein may be integrated into a single device, such as a system on a chip (“SOC”), a system on a package (“SOP”), or an ASIC device.

[0032] Embodiments may include computer programs that embody the functions described and illustrated herein, wherein the computer programs are implemented in a computer system that includes instructions stored in a machine-readable medium and a processor that executes these instructions. However, it should be clear that there may be many different ways to implement embodiments in computer programming, and an exemplary embodiment should not be interpreted as being limited to any set of computer program instructions unless otherwise specified for the embodiment. Further, a skilled programmer will be able to write such a computer program based on the flowcharts, algorithms, and associated descriptions attached to the application text to implement a certain embodiment in the disclosed embodiments. Therefore, it is considered unnecessary to disclose a specific set of program code instructions for a full understanding of how to make and use the embodiments. Further, it will be understood by those skilled in the art that one or more aspects of the embodiments described herein may be performed by hardware, software, or a combination thereof, such as may be embodied in one or more computing systems. In addition, any reference to an action performed by a computer should not be interpreted as being performed by a single computer, because more than one computer may perform the action.

[0033] The example embodiments described herein can be used with computer hardware and software that perform the previously described methods and processing functions. The systems, methods, and processes described herein can be embodied in a programmable computer, computer executable software, or digital circuitry. The software can be stored on a computer readable medium. For example, a computer readable medium can include a floppy disk, RAM, ROM, hard disk, removable media, flash memory, memory stick, optical media, magneto-optical media, CD-ROM, etc. The digital circuitry can include an integrated circuit, a gate array, a building block logic, a field programmable gate array (FPGA), etc.

[0034] The example systems, methods, and actions described in the previously presented embodiments are illustrative, and in alternative embodiments, certain actions may be performed in a different order, performed in parallel with each other, omitted entirely, and / or combined between different example embodiments, and / or certain additional actions may be performed without departing from the scope and spirit of the various embodiments. Such alternative embodiments are therefore included in the description herein.

[0035] As used herein, the singular forms "one", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should be further understood that the terms "include" and / or "comprise" used in this specification specify the presence of stated features, wholes, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, parts, and / or their collections. As used herein, the term "and / or" includes any and all combinations of one or more items in the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted as including X and Y. As used herein, phrases such as "between about X and Y" refer to "between about X and Y". As used herein, phrases such as "from about X to Y" refer to "from about X to about Y".

[0036] As used herein, "hardware" may include a combination of discrete components, integrated circuits, application specific integrated circuits, field programmable gate arrays, or other suitable hardware. As used herein, "software" may include one or more objects, agents, threads, lines of code, subroutines, separate software applications, two or more lines of code or other suitable software structures operated in two or more software applications on one or more processors (wherein the processor includes one or more microcomputers or other suitable data processing units, memory devices, input and output devices, displays, data input devices such as keyboards or mice, peripheral devices such as printers and speakers, associated drivers, control cards, power supplies, network devices, docking station devices, or other suitable devices operating in conjunction with processors or other devices under the control of a software system), or other suitable software structures. In an exemplary embodiment, software may include one or more lines of code or other suitable software structures operated in a general software application such as an operating system, and one or more lines of code or other suitable software structures operated in a special software application. As used herein, the term "coupled" and its cognates (such as "coupled" and "connected") may include physical connections (such as copper conductors), virtual connections (such as through randomly assigned memory locations of a data storage device), logical connections (such as through logic gates of a semiconductor device), other suitable connections, or suitable combinations of such connections. The term "data" may refer to suitable structures for using, transmitting, or storing data, such as data fields, data buffers, data messages having data values ​​and sender / receiver address data, control messages having data values ​​and one or more operators that cause a receiving system or component to perform a function using the data, or other suitable hardware or software components for electronic processing of data.

[0037] Generally, a software system is a system that operates on a processor to respond to a predetermined data field to perform a predetermined function. For example, a system can be defined by the function performed by the system and the data field where the function is performed. As used herein, a NAME system (wherein NAME is usually the name of a general function performed by the system) refers to a software system that is configured to operate on a processor and perform the disclosed function on a disclosed data field. Unless a specific algorithm is disclosed, any suitable algorithm for performing functions using associated data fields that those skilled in the art should know falls within the scope of the present disclosure. For example, a message system that generates a message including a sender address field, a receiver address field, and a message field will include software that operates on a processor, and the software can obtain a sender address field, a receiver address field, and a message field from a suitable system or device such as a buffer device or a buffer system of the processor, and the sender address field, the receiver address field, and the message field can be combined into a suitable electronic message format (such as an email message, a TCP / IP message, or any other suitable message format with a sender address field, a receiver address field, and a message field), and an electronic message transceiving system and device of a processor can be used to send an electronic message through a communication medium such as a network. Those of ordinary skill in the art will be able to provide specific coding for specific applications based on the foregoing disclosure, which is intended to illustrate exemplary embodiments of the present disclosure rather than to provide tutorials for those who are not as specialized as those skilled in the art (such as those who are not familiar with programming in a suitable programming language or processor). Specific algorithms for performing functions may be provided in the form of a flowchart or other suitable format, wherein data fields and related functions may be illustrated in an exemplary order of operations, wherein the order may be rearranged appropriately, and is not intended to be limiting unless explicitly stated to be the case.

[0038] The embodiments of the above disclosure have been given for the purpose of illustration and to enable one of ordinary skill in the art to practice the disclosure, but the disclosure is not intended to be exhaustive or limited to the forms disclosed. Many insubstantial modifications and variations will be apparent to one of ordinary skill in the art without departing from the scope and spirit of the disclosure. The scope of the claims is intended to broadly cover the disclosed embodiments and any such modifications. In addition, the following clauses represent additional embodiments of the disclosure and should be considered within the scope of the disclosure:

[0039] Item 1, a mass flow controller, comprising: an inlet configured to receive a fluid; a flow path through which the fluid flows; a valve configured to regulate a forward flow of the fluid out of an outlet of the mass flow controller; at least one sensor configured to monitor the fluid passing through the flow path and valve operation; and a controller communicatively coupled to the at least one sensor and the valve, the controller being adjusted to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller further comprising a diagnostic system configured to: determine at least one predetermined value associated with a reverse flow of the fluid; and control the operation of the controller based on the at least one predetermined value;

[0040] Clause 2, a mass flow controller as described in clause 1, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate;

[0041] Clause 3, a mass flow controller as described in Clause 1, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate over a period of time;

[0042] Clause 4. The mass flow controller of clause 1, wherein the diagnostic system is further configured to record a date, a time, and a device identifier in response to determining the at least one predetermined value;

[0043] Clause 5. The mass flow controller of clause 1, wherein the diagnostic system is further configured to cause the controller to enter one of a hard fault and a safe state;

[0044] Clause 6. The mass flow controller of clause 1, further comprising a central controller configured to: receive diagnostic data from a plurality of controllers; and control operation of at least one controller of the plurality of controllers;

[0045] Clause 7, a diagnostic system for controlling operation of a mass flow controller, the diagnostic system comprising: a controller communicatively coupled to at least one sensor and a valve, the controller being regulated to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller being configured to: determine at least one predetermined value associated with a reverse flow of a fluid; control operation of the controller based on the at least one predetermined value;

[0046] Clause 8, a diagnostic system as described in clause 7, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate;

[0047] Clause 9, a diagnostic system as described in Clause 7, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate over a period of time;

[0048] Clause 10. The diagnostic system of clause 7, wherein the controller is further configured to record a date, a time, and a device identifier in response to determining the at least one predetermined value;

[0049] Clause 11, the diagnostic system of clause 7, wherein the controller is further configured to cause the controller to enter one of a hard fault and a safe state;

[0050] Clause 12. The diagnostic system of clause 7, further comprising a central controller configured to: receive diagnostic data from a plurality of controllers; and control the operation of at least one controller of the plurality of controllers;

[0051] Clause 13, a method of controlling operation of a mass flow controller, the method comprising: receiving data from at least one sensor; controlling a valve based on a predetermined set point value and communications from the at least one sensor; determining at least one predetermined value associated with reverse flow of a fluid; controlling operation of the controller based on the at least one predetermined value;

[0052] Clause 14, the method as described in Clause 13, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate;

[0053] Clause 15, the method as described in Clause 13, wherein the predetermined value of the flow rate is a certain percentage of the total flow rate within a period of time;

[0054] Clause 16. The method of clause 13, further comprising: recording a date, a time, and a device identifier in response to determining the at least one predetermined value;

[0055] Clause 17, the method of clause 13, further comprising: causing the controller to enter one of a hard fault and a safe state;

[0056] Clause 18. The method of clause 13, further comprising: receiving diagnostic data from a plurality of controllers at the central controller; and controlling operation of at least one controller of the plurality of controllers.

Claims

1. A mass flow controller, comprising: an inlet configured to receive a fluid; a flow path through which the fluid flows; a valve configured to regulate a forward flow of the fluid out of an outlet of the mass flow controller; at least one sensor configured to monitor fluid flow through the flow path and valve operation; as well as a controller communicatively coupled to the at least one sensor and the valve, the controller being adapted to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller further comprising a diagnostic system configured to: monitoring reverse flow of fluid through the flow path; comparing the reverse flow rate with a predetermined value; and controlling operation of the mass flow controller based on the comparison; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

2. The mass flow controller according to claim 1, wherein: The diagnostic system is further configured to record a date, time, and device identifier in response to the reverse flow exceeding the predetermined value.

3. The mass flow controller according to claim 1, wherein: The diagnostic system is further configured to cause the controller to enter one of a hard fault and a safe state in response to the reverse flow exceeding the predetermined value.

4. The mass flow controller of claim 1 , further comprising a central controller, wherein the central controller is configured to: receiving diagnostic data from a plurality of other mass flow controllers; and The operation of at least one mass flow controller of the plurality of other mass flow controllers is controlled.

5. A diagnostic system for controlling the operation of a mass flow controller, the diagnostic system comprising: a controller communicatively coupled to at least one sensor and to the valve, the controller being adapted to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller being configured to: monitoring reverse flow of fluid through a flow path of the mass flow controller; comparing the reverse flow rate with a predetermined value; and controlling operation of the mass flow controller based on the comparison; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

6. The diagnostic system of claim 5, wherein: The controller is further configured to record a date, time, and device identifier in response to the reverse flow exceeding the predetermined value.

7. The diagnostic system of claim 5, wherein: The controller is further configured to cause the controller to enter one of a hard fault and a safe state in response to the reverse flow exceeding the predetermined value.

8. The diagnostic system of claim 5, further comprising a central controller, wherein the central controller is configured to: receiving diagnostic data from a plurality of other mass flow controllers; and The operation of at least one mass flow controller of the plurality of other mass flow controllers is controlled.

9. A method of controlling the operation of a mass flow controller, the method comprising: receiving data from at least one sensor; controlling a valve based on a predetermined set point value and communications from the at least one sensor; monitoring reverse flow of fluid through a flow path of the mass flow controller; comparing the reverse flow rate with a predetermined value; as well as controlling operation of the mass flow controller based on the comparison; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

10. The method of claim 9, further comprising: A date, time, and device identifier are recorded in response to the reverse flow exceeding the predetermined value.

11. The method of claim 9, further comprising: The controller is caused to enter one of a hard fault and a safe state in response to the reverse flow exceeding the predetermined value.

12. The method of claim 9, further comprising: receiving diagnostic data at a central controller from a plurality of other mass flow controllers; and controlling the operation of at least one mass flow controller of the plurality of other mass flow controllers.

13. A mass flow controller comprising: an inlet configured to receive a fluid; a flow path through which the fluid flows; a valve configured to regulate a forward flow of the fluid out of an outlet of the mass flow controller; at least one sensor configured to monitor fluid flow through the flow path and valve operation; as well as a controller communicatively coupled to the at least one sensor and the valve, the controller being adapted to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller further comprising a diagnostic system configured to: determining at least one predetermined value associated with a reverse flow of the fluid; controlling operation of the controller based on the at least one predetermined value; and When the reverse flow exceeds the predetermined value, the controller enters one of a hard fault state and a safe state; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

14. A diagnostic system for controlling the operation of a mass flow controller, the diagnostic system comprising: a controller communicatively coupled to at least one sensor and to the valve, the controller being adapted to control the valve based on a predetermined set point value and communications from the at least one sensor, the controller being configured to: determining at least one predetermined value associated with a reverse flow of the fluid; controlling operation of the controller based on the at least one predetermined value; and When the reverse flow exceeds the predetermined value, the controller enters one of a hard fault state and a safe state; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

15. A method of controlling the operation of a mass flow controller, the method comprising: receiving data from at least one sensor; controlling a valve based on a predetermined set point value and communications from the at least one sensor; determining at least one predetermined value associated with a reverse flow of the fluid; controlling operation of a controller based on the at least one predetermined value; and When the reverse flow exceeds the predetermined value, the controller enters one of a hard fault state and a safe state; The predetermined value is a certain percentage of the total flow or a certain percentage of the total flow within a period of time.

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