Process valve device, process automation system and method

Abstract

The invention relates to a process valve device (2) for process automation, comprising a valve element (6) for influencing a process fluid, in particular a liquid to be dispensed, preferably metered, wherein the process valve device (2) has a pneumatic drive section (7) for driving the valve element (6), wherein the drive section (7) comprises a piston (8) coupled to the valve element (6) and at least one pressure chamber (9) acting on the piston (8), wherein the process valve device (2) further comprises a control device (19) which is configured to perform position control for positioning the piston (8) and / or valve element (6) along a positioning path by pneumatically actuating the at least one pressure chamber (9), in order to thereby influence the process fluid with the valve element (6).

Description

[0001] The invention relates to a process valve device for process automation, comprising a valve element for influencing a process fluid, in particular a liquid to be dispensed, preferably metered.

[0002] The process valve device is, for example, a backflow preventer, which can also be called a suck-back valve, and serves in particular to dispense a liquid onto a wafer and, after the dispensing of the liquid, to create a vacuum by positioning the valve element in order to prevent the liquid from dripping back on.

[0003] Conventionally, the positioning of the valve element is determined by means of an adjusting screw, which limits a positioning path of the valve element, in particular a stroke, or the valve element is positioned via an electric motor, in particular a stepper motor.

[0004] One object of the invention is to provide an improved process valve device.

[0005] The problem is solved by a process valve device according to claim 1. The process valve device has a pneumatic drive section for driving the valve element, wherein the drive section comprises a piston coupled to the valve element and at least one pressure chamber acting on the piston, wherein the process valve device further comprises a control device configured to perform position control for positioning the piston and / or valve element along a positioning path by pneumatically actuating the at least one pressure chamber, in order to thereby influence the process fluid with the valve element.

[0006] Compared to the aforementioned conventional method of determining the positioning, particularly the stroke, by means of an adjusting screw, the approach according to the invention offers the particular advantage that the positioning is easier and more flexibly configurable and / or adjustable. In particular, the positioning path, especially the stroke, of the valve element can be digitally configured. Furthermore, the position control can reduce or eliminate the thermal dependence that can occur with the conventional approach using the adjusting screw due to coefficients of thermal expansion.

[0007] Compared to the aforementioned conventional approach using an electric motor, the main advantage is that there is no motor that heats up – and therefore does not need to be taken into account. Furthermore, reduced energy consumption and / or a more space-efficient implementation can be achieved.

[0008] Advantageous further training is the subject of the sub-claims.

[0009] The invention further relates to a process automation system comprising the process valve device and a wafer, wherein the process valve device is configured to dispense the process fluid onto the wafer.

[0010] The invention further relates to a method for operating the process valve device or the process automation system, comprising the step of: performing pneumatic actuation of the at least one pressure chamber, executing the position control to position the piston and / or valve element along the positioning path in order to influence the process fluid with the valve element.

[0011] Further exemplary details and embodiments are explained below with reference to the figures. Fig. 1 a schematic representation of a process automation system, Fig. 2 a block diagram of a position control system.

[0012] The Fig. Figure 1 shows a process automation system 1 comprising a process valve device 2, a compressed air source 3, and a fluid source 4. For illustrative purposes, the process automation system 1 also includes a wafer 5. The process valve device 2 serves, purely by way of example, to discharge a process fluid from the fluid source 4 onto the wafer 5.

[0013] The process automation system 1 is an exemplary application environment for the process valve device 2, which can also be provided on its own, i.e. without the other components of the process automation system 1.

[0014] The process valve device 2 is used in process automation and comprises a valve element 6 for influencing the process fluid. The process fluid is, in particular, a liquid to be dispensed, preferably metered, by means of the process valve device 2.

[0015] The process valve device 2 has a pneumatic actuator section 7 for actuating the valve member 6. The actuator section 7 comprises a piston 8 coupled to the valve member 6 and at least one pressure chamber 9 acting on the piston 8. By way of example, the pressure chamber 9 is a first pressure chamber, and the actuator section 7 also has a second pressure chamber 10 that acts on the piston 8. The second pressure chamber 10 opposes the first pressure chamber 9. The compressed air present in the first pressure chamber 9 causes a first pneumatic force that acts on the piston 8. The compressed air present in the second pressure chamber 10 causes a second pneumatic force that acts on the piston 8, specifically in the opposite direction to the first pneumatic force. By way of example, the actuator section 7 is designed as a double-acting actuator. Alternatively, the actuator section 7 can be designed as a single-acting actuator.In this case, a spring is present (especially instead of the second pressure chamber 10) which counteracts the first pressure chamber 9, i.e., acts in the opposite direction to the first pneumatic force.

[0016] Preferably, the pneumatic drive section 7 provides a linear drive. In particular, the piston 8 is set into a linear motion by the first and / or second pneumatic force.

[0017] For example, the pneumatic drive section 7 has a piston rod 11, via which the valve element 6 is coupled to the piston 8. The pneumatic drive section 7 has a drive section housing 12 in which the piston 8 and the first pressure chamber 9, and, for example, the second pressure chamber 10, are arranged. For example, the drive section 7 is designed as a pneumatic drive cylinder. The drive section housing 12 is, for instance, a cylinder housing of the drive cylinder.

[0018] The process valve device 2 expediently includes a position sensing device 13 for detecting the position of the piston 8 and / or the valve element 6. The position sensing device 13 can comprise one or more position sensing units. For example, a position sensing unit can be arranged externally on the actuator section 7, in particular externally on the actuator section housing 12. The position sensing unit can, in particular, be designed as a displacement measuring unit that can detect the position of the piston 8 along a (particularly linear) positioning path. For example, the position sensing unit comprises one or more magnetic field sensors, and a magnet is arranged on the piston and / or the piston rod, the magnetic field of which is detected by the position sensing unit.Optionally, a position sensing unit can be arranged in the drive section 7, in particular in the first pressure chamber 9 (and / or the second pressure chamber 10). The position sensing unit can, for example, include an optical sensor to detect the position of the piston 8.

[0019] Preferably, the process valve device 2 comprises a valve section 14. The valve section 14 includes the valve element 6. Advantageously, the valve section 14 includes a fluid channel 15, which serves to guide the process fluid. For example, the valve element 6 can be moved into or out of the fluid channel 15 to influence the flow of the process fluid. The valve section 14 includes a valve section housing 16 in which the valve element 6 and / or the fluid channel 15 is arranged. For example, the valve section 14 has a fluid inlet 17 and a fluid outlet 18. The fluid channel 15 extends from the fluid inlet 17 to the fluid outlet 18.

[0020] By way of example, the actuator section 7 and the valve section 14 are designed as separate components and together form a single assembly. By way of example, the actuator section 7 is attached to the valve section 14, in a manner that is particularly detachable. For example, the actuator section housing 12 is attached to the valve section housing 16, in a manner that is particularly detachable. By way of example, the piston rod 11 projects from the actuator section 7 into the valve section 14.

[0021] According to an alternative embodiment, the actuator section 7 and the valve section 14 can be integrally formed. In this case, a single, for example, one-piece, housing can be provided, which serves both as a housing for the actuator section 7 and as a housing for the valve section 14. The first pressure chamber, second pressure chamber, piston, piston rod, valve element and / or fluid channel can be arranged in this single housing.

[0022] The process valve device 2 further comprises a control device 19 for the pneumatic actuation of the drive section 7, in particular the first pressure chamber 9 and / or the second pressure chamber 10. The control device 19 comprises a control valve assembly 20 for the pneumatic actuation of the first pressure chamber 9 and / or the second pressure chamber 10. The control device 19 is configured to selectively supply or discharge compressed air to the first pressure chamber 9 and / or the second pressure chamber 10 by means of the control valve assembly 20, in order to position the piston 8 and / or the valve element 6. The control valve assembly 20 comprises, for example, a bridge circuit of four valves, in particular piezoelectric valves.

[0023] The control device 19 comprises a control unit 21, in particular a microcontroller, for controlling the control valve device 20. By way of example, the control unit 21 also serves to control a valve unit 56 and / or to read the position detection device 13, the pressure sensor device 22, the temperature sensor 57 and / or the flow sensor 58.

[0024] The process valve device 2 has a first pneumatic line 62 that runs from the control valve device 20 to the first pressure chamber 9. The process valve device 2 has a second pneumatic line 63 that runs from the control valve device 20 to the second pressure chamber 10. The process automation system 1 includes a pneumatic supply line 64 that runs from the compressed air source 3 to the control valve device 20. The pneumatic lines 62, 63, and 64 can, for example, be hoses.

[0025] The process valve device 2 comprises the pressure sensor device 22 for detecting a first pressure assigned to the first pressure chamber 9 and / or a second pressure assigned to the second pressure chamber 10. By way of example, the pressure sensor device 22 is part of the control device 19. For instance, the pressure sensor device 22 has a first pressure sensor, which is assigned, for example, to the first pneumatic line 62, and / or a second pressure sensor, which is assigned, for example, to the second pneumatic line 63.

[0026] For example, the process valve device 2 has an output element 55, which is designed, for instance, as a pipette or a nozzle. The process valve device 2 can output the process fluid via the output element 55, in particular onto the wafer 5. For example, the output element 55 is fluidically connected to the fluid outlet 18, in particular, directly connected to it.

[0027] By way of example, the process automation system 1, in particular the process valve device 2, comprises a temperature sensor 57, in particular for detecting the temperature of the process fluid and / or the environment, and / or a flow sensor 58 for detecting the flow of the process fluid, in particular through the process valve device 2. By way of example only, the temperature sensor 57 and / or the flow sensor 58 is arranged in or on the valve section 14.

[0028] By way of example, the process automation system 1, in particular the process valve device 2, comprises a valve unit 56, which is connected (fluidically) in series with the valve section 14. Advantageously, the process fluid (in particular originating from the fluid source 4) flows first through the valve unit 56 and then through the valve section 14. By way of example, the valve unit 56 is fluidically connected to the fluid inlet 17 of the valve section 14, in particular, directly connected to it. The valve unit 56 serves in particular to selectively block or allow the flow of the process fluid. The valve unit 56 is, for example, designed as a 2 / 2-way valve.

[0029] According to an alternative embodiment, the valve unit 56 is not present. In this case, the valve section 14 can, for example, be connected directly to the fluid source 4.

[0030] The operation of the process valve device 2 will be discussed in more detail below. As explained below, the operation of the process valve device 2 is controlled in particular by the control device 19. The signal processing, data processing and / or calculation operations carried out in this context are expediently performed by the control unit 21.

[0031] The control device 19 is configured to perform position control for positioning the piston 8 and / or valve element 6 along the positioning path by pneumatically actuating at least one pressure chamber, in particular the first pressure chamber 9 and / or the second pressure chamber 10, in order to influence the process fluid with the valve element 6. In particular, this influence is achieved by the valve element 6 changing the flow cross-section of the fluid channel 15 and / or contacting the process fluid and / or generating a negative pressure acting on the process fluid. The phrase "influences the process fluid" specifically means that the flow of the process fluid is influenced.

[0032] Position control (and in particular position detection) is exemplified with respect to piston 8. Through the coupling between piston 8 and valve element 6 (and expediently through a positional relationship between piston 8 and valve element 6 defined by the coupling), position control of piston 8 also results in corresponding position control of valve element 6, and / or position detection of piston 8 results in corresponding position detection of valve element 6. According to an alternative embodiment, position control and / or position detection can relate directly to valve element 6.

[0033] According to one possible embodiment, the control device 19 is configured to perform pressure control of the first pressure chamber 9 and / or the second pressure chamber 10 as part of the position control. For example, the control device 19 calculates a position error signal based on an actual position signal provided by the position sensing device 13 and a target position signal. The target position signal and the actual position signal each refer to the piston 8 or the valve element 6, respectively.

[0034] The target position signal is provided, for example, by the control device 19, and in particular calculated by it. Furthermore, the control device 19 can be configured to receive the target position signal from an external source.

[0035] The target position signal can preferably define a trajectory – in particular a temporal position profile – of the piston 8 and / or the valve element 6. For example, the trajectory defines a soft start – in particular a movement commencement in which the speed is continuously increased to a target speed – and / or a soft end – in particular a movement commencement in which the speed is continuously reduced to zero.

[0036] The control device 19 calculates a first target pressure signal for the first pressure chamber 9 and / or a second target pressure signal for the second pressure chamber 10 based on the position error signal. The control device 19 calculates a first pressure error signal based on the first target pressure signal and a first actual pressure signal related to the first pressure chamber 9, acquired by the pressure sensor device 22, and / or calculates a second pressure error signal based on the second target pressure signal and a second actual pressure signal related to the second pressure chamber 10, acquired by the pressure sensor device 22.

[0037] Using the control valve device 20, the control device 19 vents or vents the first pressure chamber 9 according to the first pressure fault signal, so that the first pressure fault signal becomes smaller, and / or vents or vents the second pressure chamber 10 according to the second pressure fault signal, so that the second pressure fault signal becomes smaller.

[0038] Preferably, the control device is designed to position the piston and / or the valve element along the positioning path with a positioning accuracy of at least 100 µm. A positioning accuracy of at least 100 µm means, in particular, that the positioning error, i.e., the deviation between the target position signal and the actual position signal, is a maximum of 100 µm, especially in a steady state, i.e., a state in which the target position signal does not change.

[0039] Preferably, the process valve device 2 is a backflow preventer. A backflow preventer can also be called a suck-back valve. The control device 19 is designed to generate a vacuum by positioning the piston 8 and / or valve element 6 along its positioning path (by means of position control) in order to prevent the process fluid from dripping out of the output element 55. The vacuum is generated, for example, by moving the valve element 6 out of the fluid channel 15, i.e., in the position shown. Fig. 1, for example, is moved upwards. Advantageously, the process valve device 2 is configured to perform a back-suction movement with the valve element 6, in particular according to a predetermined back-suction trajectory (as a target position signal) in order to generate the negative pressure and prevent dripping. The back-suction trajectory can be stored in the control unit 21.

[0040] Optionally, a backflow volume is defined in the control unit 21. Based on this backflow volume, the control unit 21 can determine the backflow trajectory and / or a backflow position along the positioning path. The process valve device 2 can move to the backflow position with the piston 8 and / or the valve element 6 to generate the vacuum. Preferably, the backflow volume, the backflow trajectory, and / or the backflow position are configurable by a user, for example, using a mobile device that communicates with the control unit 21.

[0041] For example, the process valve device 2 initially dispenses process fluid via the output element 55, in particular onto the wafer 5. The process valve device 2 then terminates the dispensing of the process fluid, for example, by the control device 19 placing the valve unit 56 in a closed state and / or pneumatically actuating the drive section 7 such that the valve element 6 is moved and thereby creates a vacuum that draws in the process fluid located in the fluid channel 15 and / or in the output element 55 and thus prevents the process fluid from dripping from the output element 55. The positioning carried out to generate the vacuum is performed, in particular, with a positioning accuracy of at least 100 µm.

[0042] Preferably, the control device 19 is configured to adjust the positioning of the valve element 6 based on viscosity information and / or temperature information, the positioning serving in particular to prevent dripping of the process fluid. The viscosity information describes the viscosity of the process fluid. The temperature information describes the temperature of the process fluid and / or the environment. The temperature information is acquired, for example, by means of the temperature sensor 57. Preferably, the control device is configured to provide the viscosity information based on the temperature information, in particular to calculate it. For example, the control device 19 is configured to calculate the viscosity information using a machine learning model.The machine learning model expediently maps the temperature information to the viscosity information and is preferably stored in the control device 19, in particular the control unit 21.

[0043] The viscosity of the process fluid can change depending on the temperature. Depending on the viscosity, a different positioning of the valve element 6 may be required to prevent dripping of the process fluid and / or to achieve a desired effect on the process fluid. Optionally, the control unit 21 adjusts the backflow volume, backflow trajectory, and / or backflow position based on the viscosity and / or temperature information.

[0044] Optionally, the control device 19 is configured to perform flow control of the process fluid while implementing position control. For example, the control device 19 calculates a flow error signal based on an actual flow signal provided by the flow sensor 58 and a target flow signal. The actual flow signal describes the flow of the process fluid through the valve section 14. The control device 19 is preferably configured to calculate the target position signal according to the flow error signal, in particular such that positioning the valve element 6 according to the target position signal reduces the flow error signal. Preferably, the control device 19 takes temperature information and / or viscosity information into account during flow control, especially when calculating the target position signal.

[0045] As mentioned above, the process fluid serves in particular to deliver the process fluid onto wafer 5. The process fluid is, for example, a cleaning fluid, a rinsing fluid, or a photoresist.

[0046] According to one possible embodiment, the process valve device 2 has a flow control mode, in which the process valve device 2 (as explained above) controls the flow of the process fluid, and a backflow mode, in which the process valve device 2 (as explained above) prevents dripping. For example, the process valve device 2 initially assumes the flow control mode, particularly to discharge the process fluid onto the wafer 5. In the flow control mode, the valve element 6 serves to control the flow of the process fluid. The process valve device 2 then switches from the flow control mode to the backflow mode. In the backflow mode, the valve element 6 serves to generate a vacuum to prevent dripping of the process fluid.

[0047] With reference to the Fig. Section 2 below describes a position control system implemented by the control device 19, which, in particular, achieves the aforementioned positioning accuracy of at least 100 µm. The position control system is explained below with regard to an actuator element. In this context, the actuator element is defined as the arrangement consisting of the piston 8 and the valve element 6. The units involved in the position control system described below (except for the actuator assembly 40 described below) are expediently implemented as software, which is executed on the control device 19, in particular the control unit 21. It should be noted that the units implemented as software are preferably to be understood as purely functional, i.e., in particular as calculation functions, which, for example, can be provided as a single function block and / or combined in function blocks.

[0048] The control device 19 comprises a target position generation unit 23, which is configured to generate the target position signal 24. The target position signal 24 specifies a target position for the actuator.

[0049] Optionally, the target position generation unit 23 also generates a target speed signal 49 and / or a target acceleration signal 50 and / or a target jerk signal.

[0050] The control device 19 comprises a position controller 25, which receives the target position signal 24 (and optionally the target velocity signal 49 and / or the target acceleration signal 50 and / or the target jerk signal). The position controller 25 is configured to generate a mass flow setpoint signal 36, which is the basis for a first compressed air mass flow (into / out of the first pressure chamber 9) and a second compressed air mass flow (into / out of the second pressure chamber 10). The compressed air mass flows are set via the control valve device 20.

[0051] The position controller device 25 is preferably designed to generate the mass flow setpoint signal 36 taking into account an actual acceleration signal 45 (related to the actuator element).

[0052] The position control device 25 comprises a position control unit 26 and preferably a linearization unit 27.

[0053] For example, the position controller unit 26 comprises a subtraction element 28, a position controller element 29 and optionally a feedforward element 30 and / or an addition element 51.

[0054] The position controller unit 26 is configured to generate a position controller signal 31 that defines a compressed air mass flow rate. For example, the position controller signal 31 specifies the first compressed air mass flow rate and / or the second compressed air mass flow rate. In particular, the position controller signal 31 can specify the magnitude of the first compressed air mass flow rate and / or the second compressed air mass flow rate. For example, the position controller signal 31 specifies the same magnitude for both compressed air mass flows (and the two compressed air mass flows then have, for example, different signs or directions). Preferably, the position controller signal 31 is a scalar signal.

[0055] The linearization unit 27 is configured to generate, and in particular to calculate, the mass flow setpoint signal 36 based on the position controller signal 31, taking into account a non-linear model of the pneumatic actuator. Preferably, the complete non-linear model of the pneumatic actuator is transformed into a linear model in the neutral position by means of a modified exact input / output linearization using the linearization unit 27. The pneumatic actuator is defined as the combination of the drive section 7 and the valve section 14. The position controller unit 26 is expediently designed for the transformed, linear neutral position model. Preferably, the mass flow setpoint signal 36 is a scalar signal.

[0056] Advantageously, the linearization unit 27 takes into account the actual position signal 32 (related to the actuator element), an actual velocity signal 44 (related to the actuator element), the first actual pressure signal 41 (related to the first pressure chamber 9), and / or the second actual pressure signal 42 (related to the second pressure chamber 10) when generating the mass flow setpoint signal 36. The actual position signal 32 is acquired in particular by the position detection device 13. The actual velocity signal 44 is the derivative of the actual position signal. The actual pressure signals 41 and 42 are acquired in particular by the pressure sensor device 22.

[0057] In particular, the linearization unit 27 models a current state of the pneumatic actuator, especially related nonlinearities of the pneumatic actuator, on the basis of the actual position signal 32, actual speed signal 44 and the actual pressure signals 41, 42, in order to expediently generate the mass flow setpoint signal 36 in such a way that it has the same effect on the pneumatic actuation of the pneumatic actuator (for example, on the compressed air mass flows) as the position controller signal 31 underlying the mass flow setpoint signal 36 would have in a state in which the actuator element is in a neutral position.

[0058] For example, the position controller unit 26 calculates the position controller signal 31 based on the target position signal 24 (and optionally the target speed signal and / or the target acceleration signal and / or the target jerk signal) as well as on the basis of the actual position signal 32 (and optionally the actual speed signal 44 and / or an actual acceleration signal 45).

[0059] Preferably, the position controller device 25 is designed to provide the position controller signal 31 underlying the mass flow setpoint signal 36 without an I component.

[0060] Preferably, the position controller device 25 is configured to generate the position controller signal 31 without considering an actual pressure signal 41, 42 related to the pneumatic actuator. In particular, no actual pressure signal 41, 42 is fed back to the position controller unit 26. Because no actual pressure signal relating to the pneumatic actuator is fed back to the position controller unit 26, an integral behavior of the system can be achieved.

[0061] The subtraction element 28 calculates a difference between the target position signal 24 and the actual position signal 32 (and optionally between the target speed signal 49 and the actual speed signal 44 and / or between the target acceleration signal 50 and the actual acceleration signal 45). The subtraction element 28 provides the one or more calculated differences as one or more deviation signals 33.

[0062] The position controller element 29 calculates a position controller signal 34 based on one or more deviation signals 33, in particular to achieve a (magnitude) reduction of the one or more deviation signals 33. For example, the position controller element 29 has a proportional (P) element for calculating the position controller signal 34.

[0063] The pilot element 30 calculates a pilot signal 35 based on the target position signal 24 (and optionally the target speed signal 49 and / or the target acceleration signal 50 and / or the target jerk signal). The pilot element 30 expediently has feed-in gains with which the pilot element 30 calculates the pilot signal 35.

[0064] The adding element 51 calculates the position controller signal 31 on the basis of, in particular as a sum of, the position controller signal 34 and the feedforward signal 35.

[0065] According to an alternative embodiment (in which, in particular, the feedforward element 30 and the add-in element 51 are not present), the position controller element signal 34 is used as the position controller signal 31.

[0066] The control device 19 has a mean pressure regulator unit 37 which is designed to perform pressure control of a mean pressure of the first pressure chamber 9 and second pressure chamber 10 as part of the position control.

[0067] As an example, the intermediate pressure regulator unit 37 calculates target mass flow signals 38 based on the mass flow setpoint signal 36 and taking into account one or more actual pressure signals 41, 42 relating to the pressure chambers 9, 10. The target mass flow signals 38 form the basis for the pneumatic actuation of the pressure chambers 9, 10. In particular, the intermediate pressure regulator unit 37 generates a first target mass flow signal, which specifies a target value for the first mass flow relating to the first pressure chamber 9, and a second target mass flow signal, which specifies a target value for the second mass flow relating to the second pressure chamber 10.

[0068] Advantageously, the mean pressure regulator unit 37 generates the target mass flow signals 38 such that the actual mean pressure of the two pressure chambers 9, 10 is changed towards a target mean pressure. Preferably, the mean pressure regulator unit 37 calculates the actual mean pressure based on the actual pressure signals 41, 42, in particular as the average of the two actual pressure signals 41, 42.

[0069] Preferably, the mean pressure regulator unit 37 generates the target mass flow signals 38 such that the first compressed air mass flow is equal to the negative of the second compressed air mass flow, provided that no adjustment of the actual mean pressure is required (for example, if the actual mean pressure corresponds to the target mean pressure). The magnitude of the first target mass flow signal and / or the second target mass flow signal is expediently predetermined by or corresponds to the mass flow setpoint signal 36 (in particular, weighted according to the respective piston area of ​​the piston 8 and / or especially in the case where no adjustment of the actual mean pressure is required).

[0070] The term associated piston area shall be defined as the piston area of ​​the actuator element that limits the respective associated pressure chamber 9, 10.

[0071] Optionally, the center pressure regulator unit 37 takes into account the actual position signal 32 and / or the actual speed signal 44 when calculating the target mass flow signals 38. For example, the center pressure regulator unit 37 calculates the volumes of the pressure chambers 9, 10 based on the actual position signal 32 and calculates the target mass flow signals 38 taking the calculated volumes into account.

[0072] For example, the first compressed air mass flow enters the first pressure chamber 9 (and is considered a positive compressed air mass flow), and the second compressed air mass flow flows out of the second pressure chamber 10 (and is considered a negative compressed air mass flow 47). If the actual mean pressure (i.e., an average value formed from the first actual pressure signal 41 and the second actual pressure signal 42) corresponds to the target mean pressure, the mean pressure regulator unit 37 generates the two target mass flow signals 38 with the same magnitude (or weighted according to the respective piston area of ​​the actuator element), where, for example, the first target mass flow signal is positive and the second target mass flow signal is negative. If the actual mean pressure is less than the target mean pressure, then the mean pressure regulator unit 37 increases the amount of the first target mass flow signal and / or decreases the amount of the second target mass flow signal.If the actual mean pressure is greater than the target mean pressure, then the mean pressure regulator unit 37 reduces the magnitude of the first target mass flow signal and / or increases the magnitude of the second target mass flow signal.

[0073] For example, the mean pressure regulator unit 37 first generates the two target mass flow signals with the amount specified by the mass flow setpoint signal 36 (preferably weighted according to the respective assigned piston area of ​​the actuator element and in particular with different signs) and then, as described above, adjusts each target mass flow signal for the purpose of pressure control of the mean pressure, in particular by increasing the amount of one of the two target mass flow signals and / or decreasing the amount of the other target mass flow signal.

[0074] The control device 19 is specifically designed to adjust the compressed air mass flows within the framework of position control such that an integral behavior of a compressed air mass flow to a pressure assigned to the pneumatic actuator is given. For example, an integral behavior of the first compressed air mass flow to the first actual pressure signal 41 and / or an integral behavior of the second compressed air mass flow to the second actual pressure signal 42 is given. The integral behavior is achieved in particular by separate adjustment of the compressed air mass flows and the intermediate pressure regulator unit 37.

[0075] The control device 19 comprises a mass flow control unit 39, which generates control signals 48 based on the target mass flow signals 38. The control signals 48 are, for example, electrical voltages. The control signals 48 can also be referred to as valve position signals.

[0076] The conversion of the target mass flow signals 38 into the control signals 48 is expediently carried out taking into account the actual pressure signals 41, 42. The mass flow control unit 39 expediently does not perform mass flow control. In particular, the process automation system 1 does not have a mass flow sensor for detecting the first compressed air mass flow 46 and / or the second compressed air mass flow 47.

[0077] For example, the mass flow control unit 39 calculates the control signals 48 taking into account a valve characteristic curve and flow function of the respective valve and / or an opening point of the respective valve and / or the atmospheric pressure applied to the respective valve. As an example, the actual pressure signals 41, 42, an actual supply pressure signal 52 and / or an actual exhaust air pressure signal 53 are supplied to the mass flow control unit, and the mass flow control unit 39 calculates the control signal 48 taking these signals into account. For example, the mass flow control unit 39 calculates the atmospheric pressure applied to the respective valve as the pressure ratios of one of the actual pressure signals and the actual supply pressure signal 52 or the actual exhaust air pressure signal 53.The actual exhaust air pressure signal 53 conveniently refers to the air pressure of a compressed air sink, for example, the environment into which the control valve assembly 20 discharges the compressed air from the pressure chambers 9, 10. A suitable pressure sensor is conveniently provided to detect the actual exhaust air pressure signal 53. The actual supply pressure signal 52 refers to the air pressure of the compressed air supplied by the compressed air source 3. A suitable pressure sensor is conveniently provided to detect the actual supply pressure signal 52.

[0078] The block designated with the number 40 shall be referred to as actuator unit 40. Actuator unit 40 is part of the process automation system 1 and comprises the control valve unit 20 and the pneumatic actuator. Actuator unit 40, in particular the control valve unit 20, and specifically its valves, are controlled by control signals 48. The control signals 48 primarily adjust the valve opening size. Compressed air mass flows pass through the valve openings. By controlling the valve unit, the compressed air mass flows adjust themselves according to the target mass flow signals. The mass flows cause a change in the pressures in the pressure chambers 9, 10 and / or a change in the position of the actuator element.

[0079] The pressure sensor device 22 detects the first actual pressure signal 41, which is assigned to the first pressure chamber 9, and the second actual pressure signal 42, which is assigned to the second pressure chamber 10. Preferably, the first actual pressure signal 41 describes the air pressure in the first pressure chamber 9 and the second actual pressure signal 42 describes the air pressure in the second pressure chamber 10. The position detection device 13 detects the actual position signal 32, which in particular describes the position of the actuator element.

[0080] The control device 19 comprises a differentiator unit 43, which is configured to generate the actual acceleration signal 45 based on a detected position of the actuator element. For example, the differentiator unit 43 calculates the actual velocity signal 44 and / or the actual acceleration signal 45 based on the actual position signal 32.

[0081] The differentiator unit 43 expediently includes a filter for providing the actual acceleration signal 45. The bandwidth of the filter is expediently set as a function of the noise characteristics of the position sensing device 13 such that a predefinable noise amplitude in the control signal – for example, the control signals 48 – is not exceeded. Preferably, the bandwidth and feedback gains are determined such that a predetermined control variable noise level is not exceeded.

[0082] The linearization unit 27 is preferably configured to convert the position controller signal 31 into the mass flow setpoint signal 36 within the framework of a linearization, in particular a feedback linearization, so that for the position controller unit 26 a position control loop section of the position control comprising the linearization unit 27 and the pneumatic actuator functions as a linear control system, in particular as a linear control system in which the actuator element is in the neutral position.

[0083] The position control unit 26 receives the remaining part of the signal in the Fig.The position control loop shown in Figure 2 – specifically, the section of the position control loop from the linearization unit 27 to the differentiator unit 43 – is considered a linear position control system. Consequently, the position controller unit 26 can be designed with a correspondingly simple design. In particular, the position control loop section formed by the linearization unit 27, the mean pressure controller unit 37, the mass flow control unit 39, the actuator 40, and the differentiator unit 43 constitutes a position control system, specifically a linear position control system, for the position controller unit 26. This position control system can be controlled by the position controller unit 26 without the position controller unit 26 having to consider, or taking into account, any pressure or non-linearity of the actuator 40 (resulting in particular from pneumatic effects).

[0084] Examples of feedback linearizations are described, for example, in J.-J. Slotine and W. Li, "Applied Nonlinear Control", Prentice Hall, 1991. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] J.-J. Slotine and W. Li “Applied Nonlinear Control”, Prentice Hall, 1991

[0084]

Claims

[1] Process valve device (2) for process automation, comprising a valve element (6) for influencing a process fluid, in particular a liquid to be dispensed, preferably metered, wherein the process valve device (2) has a pneumatic drive section (7) for driving the valve element (6), wherein the drive section (7) comprises a piston (8) coupled to the valve element (6) and at least one pressure chamber (9) acting on the piston (8), wherein the process valve device (2) further comprises a control device (19) which is configured to perform position control for positioning the piston (8) and / or valve element (6) along a positioning path by pneumatically actuating the at least one pressure chamber (9), in order to thereby influence the process fluid with the valve element (6). [2] Process valve device (2) according to claim 1, wherein the control device (19) is configured to position the piston (8) and / or the valve element (6) within the framework of position control with a positioning accuracy of at least 100 µm along the positioning path. [3] Process valve device (2) according to a preceding claim, wherein the process valve device (2) is a backflow preventer and has an output element (55) for outputting the process fluid, and the control device (19) is configured to generate a vacuum by positioning the piston (8) and / or valve element (6) along the positioning path in order to prevent the process fluid from dripping out of the output element (55). [4] Process valve device (2) according to a preceding claim, wherein the drive section (7) is designed as a pneumatic drive cylinder. [5] Process valve device (2) according to a preceding claim, further comprising a valve section (14) comprising the valve element (6) and a fluid channel (15) carrying the process fluid, wherein the drive section (7) is in particular detachably attached to the valve section (14) or the drive section (7) and the valve section (14) are integrally formed together. [6] Process valve device (2) according to a preceding claim, wherein the control device (19) is configured to adjust the positioning of the valve element based on viscosity information and / or temperature information, wherein the positioning serves in particular to prevent dripping of the process fluid. [7] Process valve device (2) according to claim 6, wherein the control device (19) is configured to provide, in particular calculate, the viscosity information based on the temperature information. [8] Process valve device (2) according to claim 6 or 7, wherein the control device (19) is configured to calculate the viscosity information using a machine learning model. [9] Process valve device (2) according to a preceding claim, wherein the control device (19) is configured to perform a flow control of the process fluid by carrying out position control. [10] Process automation system (1) comprising a process valve device (2) according to one of the preceding claims and a wafer (5), wherein the process valve device (2) is configured to discharge the process fluid onto the wafer (5). [11] Process automation system (1) according to claim 10, wherein the process fluid is a cleaning fluid or a rinsing fluid or a photoresist. [12] Method for operating a process valve device (2) according to one of claims 1 to 9 or a process automation system (1) according to claim 10 or 11, comprising the step: performing the pneumatic actuation of the at least one pressure chamber (9) and executing the position control to position the piston (8) and / or valve element (6) along the positioning path in order to influence the process fluid with the valve element (6).

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