JP2023086079A - Vacuum pump - Google Patents

Abstract

To certainly execute automatic recognition of an accessory during the operation of a vacuum pump, even if different kinds of signals, especially analog signals or digital signals can be supplied to an interface of a vacuum pump.SOLUTION: A vacuum pump has an interface for connecting the vacuum pump to an accessory device, a controller connected to the interface, and a noise removal device connected to the interface and the controller. The controller is configured to recognize at least two different kinds of signals to be input in the interface, and to selectively actuate the noise removal device depending on the recognized kind of the signal to be input in the interface.SELECTED DRAWING: Figure 1

Description

The present invention relates to vacuum pumps, in particular turbomolecular pumps, with interfaces for connecting the vacuum pump to accessories.

For example, many vacuum pumps have multiple auxiliary It can be electrically connected to the device. Examples of such accessories are pressure measuring devices, air valves or cooling fans.

In addition, many vacuum pumps are capable of performing automatic recognition of attachments upon attachment of the attachments. In the case of automatic recognition, the controller of the vacuum pump automatically checks which kind of attachment is currently connected to the interface of the vacuum pump. After automatic recognition of the accessory in question, for example the correct characteristic curve can be selected for controlling the accessory in question.

Automatic recognition of the attachment can be performed by means of analog signals and characteristic impedance. The characteristic impedance resides in an accessory and is read through the interface of the vacuum pump. Alternatively, recognition of the accessory may be performed by a digital signal. The digital signal is requested by the vacuum pump through the interface and sent from the attachment as a digital data packet to the vacuum pump controller.

When connecting the vacuum pump to accessories, it is desirable to use a standard connector, such as a micro-USB connector, as an interface to reduce manufacturing costs and to increase flexibility as to which attachments can be connected. However, even when the same interface is used for all types of the attachment, i.e. whether the attachment has a characteristic impedance or is capable of transmitting digital data packets as an "intelligent" attachment. It is desirable to be able to perform automatic recognition of attachments regardless of the

However, since the number of terminal electrodes or data lines in a standard interface or connector is limited, there is a need for attachment to attachments, both analogue attachments with characteristic impedance and digital attachments with digital data packets. It is often necessary to use one common transmission line for the devices. However, noise can occur during the operation of the vacuum pump, ie when the drive motor is started, for example by the pulse width modulation of the final stage of a turbomolecular pump for controlling said drive motor. As a result, automatic recognition of the attachment is no longer possible due to the noise when recognizing the attachment by means of analog signals. Indeed, the noise can be reduced by suitable capacitors permanently connected in the area of the interface of the vacuum pump. However, with such fixedly mounted capacitors, the digital signal is short-circuited at the interface of the vacuum pump, preventing automatic recognition of the attachment by the digital data packet.

The object of the present invention is to provide a vacuum pump in which an automatic recognition of the attachments can be reliably carried out during operation of the vacuum pump, even if different types of signals, in particular analogue or digital signals, can be supplied to the interface of the vacuum pump. It is to provide a pump.

This task is solved by a vacuum pump with the features of claim 1 .

A vacuum pump, particularly a turbomolecular pump, has an interface for connecting the vacuum pump to an accessory, a controller connected to the interface of the vacuum pump, and a noise filter connected to the interface and the controller. device. The controller is configured to recognize at least two different types of signals input to the interface and selectively activate the noise canceller depending on the recognized types of signals input to the interface. It is

Each connection between the interface, the controller and the noise eliminator may be an electrical connection or an electronic connection. Furthermore, the interface may be a standard interface, such as a micro USB connector for example. For example, by using such a standard interface with common data lines for analog and digital signals, manufacturing costs for vacuum pumps are reduced compared to vacuum pumps with specially configured interfaces.

Since the controller is capable of recognizing at least two different signal types at the interface, the noise eliminator is activated or deactivated by the controller depending on the signal type so that the interface recognizes this It can automatically adapt to the type of signal. For example, attenuation of digital data packets when using "intelligent" attachments is avoided, while noise that can occur in unchanging analog signals can be suppressed by the noise eliminator. Moreover, due to such noise suppression, it is possible to distinguish more types of attachments, for example when analog signals and characteristic impedances are used in attachments.

Further advantageous configurations of the invention are described in the dependent claims, the description and the drawings.

According to one embodiment, the vacuum pump further comprises a switching device connected to the noise elimination device and the controller. In this case, the controller is configured to selectively activate the noise elimination device via the switch device. Therefore, the noise elimination device can be reliably activated or deactivated by the switch device.

The switch device may further comprise a transistor. It has been found that conventional transistors can be particularly suitable as switching devices, since they take up little installation space in a vacuum pump. Alternatively, however, the switch device may be configured as a switch or optocoupler.

The controller may be configured to recognize whether the attached device has a characteristic impedance based on the signal input to the interface. Once the presence of the characteristic impedance is recognized, a signal of the analog signal type can enter the interface. Conversely, when it is recognized that the accessory device has no characteristic impedance, a digital signal type signal may enter the interface. Thus, for this embodiment, the controller can recognize what kind of signal is entering the interface based on the presence of the characteristic impedance, and the noise canceller can be properly activated or deactivated. can be made Specifically, the controller activates the noise eliminator when the attachment has a characteristic impedance, and deactivates the attachment when the attachment does not have a characteristic impedance. Therefore, the presence of the characteristic impedance represents a unique and reliable condition for operating the noise eliminator.

Further, the controller can identify the characteristic impedance of the attached device based on the voltage applied across the two input lines of the interface. For example, a voltage within a preset range can be assigned to a particular type of accessory. Thus, for this embodiment, the controller is not only capable of distinguishing between at least two different signal types, but also distinguishes between attachment devices of different types that provide the same type of signal to the interface. can also However, when voltage cannot be measured at the two input lines of the interface, since the two input lines are, for example, open, the controller detects that no characteristic impedance is present in the attachment, i.e. digital Able to recognize signals of the type of signal input to the interface.

According to another embodiment, the noise canceller may comprise a capacitor. Since no special requirements are required for the capacitor, the noise eliminator can therefore be realized at low cost. Furthermore, the noise removal device can be configured as a low-pass filter. Therefore, the noise eliminator may include a resistor in addition to the capacitor. Likewise, no special conditions are required for the resistance. However, the value of the resistor and the value of the capacitor determine the cutoff frequency of the low pass filter. To suppress the noise caused by the drive motor of the turbomolecular pump, the value of the resistor and the value of the capacitor of the low-pass filter as a noise eliminator are useful, such that the low-pass filter has a cut-off frequency of about 1 kHz. can be designed to

According to another embodiment, the at least two different types of signals input to the interface comprise analog signals and digital signals. When the controller recognizes the analog signal, the noise eliminator is activated, and when the controller recognizes the digital signal, the noise eliminator is deactivated. Thus, regardless of whether analog signals enter the interface or digital signals enter the interface, a common data line can be used or maintained at the interface for these signals. This allows standard interfaces to be used or retained. The interface may for example be configured as a micro USB interface. The interface has, for example, a 5-pin connector. With this 5-pin connector, one pin can be shared for analog and digital input signals.

Furthermore, the invention relates to a system comprising a vacuum pump as described above and ancillaries. The vacuum pump and the accessory are connected to each other via an interface. In this case, the connection may be an electrical connection or an electronic connection. As described above, using a controller, the vacuum pump recognizes at least two different types of signals, e.g., analog signals or digital signals, entering the interface, and the recognized Depending on the type, it is configured to activate the noise eliminator.

In addition to identifying at least two types of signals at the interface, the vacuum pump is also configured to recognize the type of attachment based on the signals input to the interface. For example, the vacuum pump controller can recognize whether an attachment has a characteristic impedance and can identify the type of attachment based on the characteristic impedance, or the controller can request a digital signal and can subsequently be read to identify the attached device. The accessory device may for example comprise a pressure measuring device that provides a digital signal to the interface. Alternatively, the accessory may include, for example, an air valve or cooling fan that provides an analog signal to the interface and has a characteristic impedance.

Furthermore, the invention relates to a method for operating a vacuum pump, in particular a turbomolecular pump. in this case,
- the interface of the vacuum pump is connected to an auxiliary device,
- the controller is connected to the interface and
- A noise eliminator is connected to the interface and to the controller. in this case,
- the controller recognizes at least two different types of signals input to the interface and selectively activates the noise eliminator depending on the recognized types of signals input to the interface;

What has been described for the vacuum pump according to the invention and the system according to the invention also holds true for the method according to the invention. This is especially true for the advantages and embodiments as well.

Further, it is understood that all embodiments described herein can be combined with each other unless otherwise stated.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the accompanying drawings.

Figure 3 shows the vacuum pump of the invention connected to an accessory via an interface; Figure 2 shows the analog signal measured at the interface when the noise eliminator is deactivated. Figure 2 shows the analog signal measured at the interface when the noise eliminator is activated; Figure 2 shows the digital signal measured at the interface when the noise eliminator is not activated. Fig. 3 shows the digital signal measured at the interface when the noise eliminator is activated;

FIG. 1 schematically shows a vacuum pump 11 connected via an interface 13 to an accessory 15 . For this purpose, the accessory device 15 has a connector 16 . Furthermore, the vacuum pump 11 has a microcontroller 17 connected to the interface 13 . The vacuum pump 11 is therefore provided to be able to be connected via the interface 13 to various types of attachments 15 , the respective type of attachment 15 being automatically recognized by the microcontroller 17 .

To recognize the attachment 15 , a particular type of attachment 15 has a characteristic impedance 19 . Such an accessory 15 is for example an air valve or a cooling fan that provides the interface 17 with analog signals for the microcontroller 17 . The analog signal indicates the magnitude of characteristic impedance 19 . The microcontroller 17 recognizes the magnitude of the characteristic impedance 19, ie the type of the accessory device 15, based on this analog signal.

Another type of attachment 15, which can be considered an "intelligent" attachment and which has a serial interface, sends digital data packets via the interface 13 to the microcontroller 17 of the vacuum pump 11 in response to corresponding requests. Send to Microcontroller 17 identifies the type of attachment 15 based on the digital data packet. Such an accessory 15 is, for example, a pressure measuring device or a Bourdon tube pressure gauge.

The interface 13 is configured as a micro USB connector and has five pin or terminal connections designated X4:1-X4:5. The connector 16 of the accessory 15 has corresponding terminal connections X3:1-X3:5. However, these terminal connections are provided or used differently depending on the type of accessory device 15 . The terminal connections X4:1 and X4:4 are provided for the power lines 21,22. The power line 21 is used to power an "intelligent" or "digital" accessory 15, for example a Bourdon tube pressure gauge, with a voltage of +5V. In contrast, a power line 22 is provided for powering "analog type" attachments with +24 V, such as required by air valves or cooling fans, for example.

Furthermore, the terminal connection X4:2 for the transmission line 23 and the terminal connection X4:3 for the reception line 24 are provided in the interface 13, while the terminal connection X4:5 connects the ground line 25. It is connected to the ground (GND) via. In the case of a "digital" attachment 15, the request that the attachment 15 must output a digital data packet to the microcontroller 17 via the receive line 24 to identify the attachment 15 is sent to the attachment 15. A transmission line 23 is used to transmit to.

Since various types of attachments 15 provide digital or analog signals to identify the attachment 15, the interface 13 captures both digital data packets and analog signals corresponding to the characteristic impedance 19. For this reason, in practice it is necessary to have two different terminals X4:3 for different receiving lines 24 . Therefore, by using terminals X4.1 and X4.4 for the two power supply lines 21, 22, terminal X4.2 for the transmission line 23, and terminals X4:5 for the ground line 25, the interface 13 is , must have six terminals. However, since the standard Micro USB connector has only 5 pins, it uses a common terminal X4:3 and a common receive line 24 for both the digital signal and the analog signal. It is necessary.

Thus, for the case where attachment 15 has a characteristic impedance 19, as illustrated in FIG. 1, receive line 24 is used to capture a static analog signal. The analog voltage applied across the characteristic impedance 19 measured between the receiving line 23 and ground (GND) is analyzed by the microcontroller 17 of the vacuum pump 11, for example via a voltage divider. To identify the characteristic impedance 19, ie the type of attachment, eg air valve or cooling fan, the analog signal captured by the receive line 24 is divided into six different values, typically between 0.38V and 2.74V. be.

After starting the vacuum pump 11, the drive motor (not shown) of this vacuum pump 11 is controlled by the final pulse width modulated signal. Attachment 15 has a characteristic impedance 19 so that when an analog signal is input to receive line 24 of interface 13, the pulse width modulated signal will cause a , noise rides on the analog signal on the receive line 24 . FIG. 2A shows the signal on receive line 24 versus time relative to ground (GND) after start-up of the drive motor of vacuum pump 11 .

It can be seen that this signal is riddled with noise having an amplitude such that an accurate analysis of the voltage signal on the receive line 24 is no longer possible. Specifically, the noise makes it impossible to partition the voltage captured on the receive line 24 into six different voltage ranges within the range of 0.38V to 2.74V. Therefore, in the case shown in FIG. 2A, the type of attachment 15 cannot be recognized based on the signal entering the receive line 24 and cannot be recognized based on the corresponding characteristic impedance 19 .

In order to remove noise from the analog signal on the receiving line 24, the vacuum pump 11 has a noise removing device that constitutes a low-pass filter 31 (see FIG. 1). The low-pass filter 31 has a resistor 33 connected in series with the receiving line 24 and a capacitor 35 connected in parallel. Furthermore, the vacuum pump 11 has a switching device 37 including a transistor 39 and a control line 41 . Similarly, this switch device 37 is connected to the microcontroller 17 .

When the transistor 39 is conductively connected by the control line 41, the capacitor is connected to the ground (GND). As a result, the low-pass filter 31 acts as a nozzle remover. On the other hand, if the transistor 39 is cut off or not connected by the control line 41, the capacitor 35, ie the low-pass filter 31, does not work as a noise elimination device.

In FIG. 2B, the signal on receive line 24 is shown as voltage signal 27 after low-pass filter 31 (see FIG. 1) after activation of this low-pass filter 31 . The fluctuation or noise of the analog voltage signal 27 is significantly less after activation of the low-pass filter 31 than without activation of the low-pass filter 31 (see FIG. 2A).

As already explained, the microcontroller 17 and interface 13 of the vacuum pump 11 are also provided to identify attachments 15 that transmit digital data packets captured by the microcontroller 17 via the receive line 24 as well. ing. Microcontroller 17 sends a signal to accessory 15 via transmission line 23 to initiate transmission of the digital data packet via receive line 24 . Such capture of the digital data packets on the receive line 24 allows accurate identification of the corresponding attached device 15 using the microcontroller 17 .

However, when the switch device 37 is activated so that the low-pass filter 31 operates as a noise filter, ie when the transistor 39 is conductively connected by the control line 41, as shown in FIG. The digital signal on line 24 is shorted. 3A and 3B depict the digital signal versus time, respectively. That is, the voltage signal 27 after the low-pass filter 31 is plotted against time in the case of a "digital" attachment 15, for example a Bourdon tube pressure gauge connected to the vacuum pump 11 via the interface 13. there is

When the low-pass filter 31 is activated by the conducting transistor 39, the digital signal is short-circuited by the capacitor 35 of the low-pass filter 31, so that the attached device based on the digital data packet captured via the receive line 24 15 recognition is impossible. To avoid such unawareness, the low pass filter 31 is deactivated when a digital data packet is to be captured via the receive line 24 .

The deactivation is performed by the transistor 39 being cut off or switched "non-conducting" by the control line 41 . This deactivates the capacitor 35 and thus the low pass filter 31 . As a result, the digital data packet can be captured by the microcontroller 17 as desired. Such capture is illustrated in FIG. 3A. In this FIG. 3A the digital signal is plotted against time while low pass filter 31 is disabled by transistor 39 via control line 41 . It can also be seen in FIG. 3A that the digital signal is unaffected by the pulse width modulated signal controlling the drive motor of the vacuum pump 11 .

To ascertain whether an "analog" attachment 15 is connected to the interface 13 or a "digital" attachment 15 is connected to the interface 13, and accordingly, a constant analog signal. Microcontroller 17 checks whether a characteristic impedance 19 is present in the attachment 15 in question to see if it can capture via receive line 24 or if a digital data packet can be captured via receive line 24 . Check whether or not To check this, microcontroller 17 checks whether a measurable voltage is applied between receive line 24 and ground (GND), or if receive line 24 is open to ground. Check whether or not The attachment 15 has a characteristic impedance 19 if the voltage between the receive line 24 and ground is measurable. As a result, an unchanged analog signal can be captured on the receive line 24 . In this case, the microcontroller 17 activates the low-pass filter 31 via the control line 41 by switching on the transistor 39 . As a result, the noise of the unchanged analog signal is removed by low-pass filter 31, as shown in FIG. 2B.

However, if the attachment 15 does not have a characteristic impedance 19, then the receive line 24 will be open to ground, at which time the microcontroller 17 will not detect a voltage corresponding to the particular characteristic impedance 19. . Therefore, in this case, digital data packets can be captured on the receive line 24 . As a result, the microcontroller 17 deactivates the low-pass filter 31 via the control line 41 by switching the transistor 39 "non-conducting". Thereby, the low-pass filter 31 does not affect the digital data packet. Therefore, the digital data packet can be successfully captured, as shown in FIG. 3A.

Thus, in order to be able to capture a noise-free analog signal (see FIG. 2B) or a noise-free digital data packet (see FIG. 3A), the microcontroller 17 therefore, based on the signal on the receive line 24: Determine if the attachment 15 has a characteristic impedance 19 and activate or deactivate the low pass filter 31 accordingly. Therefore, even if the drive motor of the vacuum pump 11 is controlled by a pulse width modulated signal, by selectively activating or deactivating the low-pass filter 31, accurate automatic identification of the attachment can be achieved by analog signals (Fig. 2B) to capture the characteristic impedance 19, or by using a digital data packet (see FIG. 3A).

By appropriately designing the values of resistor 33 and capacitor 35, the cut-off frequency of low-pass filter 31 can be determined such that noise in the analog signal (see FIG. 2A) can be appropriately suppressed. In this example, an 820Ω resistor and a 220nF capacitor were chosen. As a result, a cutoff frequency of 882 Hz is obtained for the low pass filter 31 . It has been found that a cut-off frequency of 1 kHz for the low-pass filter 31 is sufficient to suppress noise that may be caused by the pulse width modulated signal for the drive motor of the turbomolecular pump.

11 Vacuum pump 13 Vacuum pump interface 15 Attachment 16 Attachment connector 17 Microcontroller 19 Characteristic impedance 21 +5V power line 22 +24V power line 23 Transmitting line 24 Receive line, input line 25 Ground line, input line 27 After low-pass filtering Voltage signal 31 Low-pass filter 33 Resistor 35 Capacitor 37 Switch device 39 Transistor 41 Control line X4:1-X4:5 Vacuum pump interface terminals X3:1-X3:5 Accessory connector terminals

Claims (15)

an interface (13) for connecting the vacuum pump (11) to an accessory (15);
a controller (17) connected to said interface (13);
said vacuum pump (11), in particular a turbomolecular pump, comprising a noise eliminator (31) connected to said interface (13) and said controller (17),
The controller (17) recognizes at least two different types of signals input to the interface (13), and depending on the recognized types of signals input to the interface (13), the noise eliminator The vacuum pump (11) configured to selectively activate (31). The vacuum pump (11) further comprises a switch device (37) connected to the noise eliminator (31) and the controller (17),
A vacuum pump (11) according to claim 1, wherein the controller (17) is arranged to selectively activate the accessory device (31) by means of the switch device (37). A vacuum pump (11) as claimed in claim 2, wherein the switching device (37) comprises a transistor (39). 2. The controller (17) is configured to recognize whether the accessory device (15) has a characteristic impedance (19) based on the signal input to the interface (13). 4. A vacuum pump (11) according to any one of claims 1 to 3. When the attachment (15) has the characteristic impedance (19), the controller (17) activates the noise elimination device (31), and the attachment (15) has the characteristic impedance (19) 5. Vacuum pump (11) according to claim 4, wherein said noise elimination device (31) is deactivated when it does not have a The controller (17) identifies a characteristic impedance (19) of the accessory (15) based on a voltage (27) applied across two input lines (24, 25) of the interface (13). A vacuum pump (11) according to claim 4 or 5. A vacuum pump (11) according to any one of the preceding claims, wherein the noise elimination device (31) comprises a capacitor (35). The vacuum pump (11) according to any one of claims 1 to 7, wherein the noise eliminator (31) is configured as a low-pass filter. A vacuum pump (11) according to any one of the preceding claims, wherein said at least two different types of signals input to said interface (13) comprise analog signals and digital signals. when the controller (17) recognizes the analog signal, the noise elimination device (31) is activated;
10. Vacuum pump (11) according to claim 9, wherein the noise eliminator (31) is deactivated when the controller (17) recognizes the digital signal. Vacuum pump (11) according to any one of the preceding claims, wherein said interface (13) is configured as a Micro USB interface. A system comprising a vacuum pump (11) according to any one of claims 1 to 11 and an accessory (15),
The system, wherein said vacuum pump (11) and said accessory (15) are connected to each other via an interface (13). 13. System according to claim 12, wherein the vacuum pump (11) is arranged to recognize the type of the attachment (15) based on a signal input to the interface (13). 14. System according to claim 12 or 13, wherein the accessory device (15) comprises a pressure measuring device, an air valve or a cooling fan. A method for operating a vacuum pump (11), in particular a turbomolecular pump, comprising:
an interface (13) of said vacuum pump (11) is connected to an accessory (15);
A controller (17) is connected to said interface (13),
a noise eliminator (31) is connected to the interface (13) and the controller (17),
The controller (17) recognizes at least two different types of signals input to the interface (13), and depending on the recognized types of signals input to the interface (13), the noise eliminator The method of selectively activating (31).

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