A multi-range vacuum gauge data acquisition method

Abstract

A kind of multi-range vacuum gauge data acquisition method for the vacuum degree measurement of vacuum cavity, it includes setting the measurement range of first vacuum gauge and second vacuum gauge, and the overlapping measurement range of the first vacuum gauge and second vacuum gauge;Respectively obtain the voltage measurement value V1 of the first vacuum gauge and the voltage measurement value V2 of second vacuum gauge;Output the result value of multi-range vacuum gauge data acquisition;And the steps of two range vacuum gauge broken line shielding.Therefore, the present application can realize the collection of vacuum value in large-span application scene, ensure higher collection accuracy, and the method can realize the automatic detection of broken line, better handle the scene that the voltage output of vacuum gauge is small and vacuum gauge broken line.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, and in particular to a multi-range vacuum gauge data acquisition method. BACKGROUND

[0002] The application of vacuum environment plays an indispensable key role in the development of semiconductor technology. Due to the complexity of semiconductor manufacturing and packaging technology, the production process from wafer die to chip product needs to go through tens of special process steps such as oxidation, sputtering, lithography, etching, ion implantation and packaging, and many of these steps cannot be separated from the application of vacuum environment. In semiconductor application equipment, such as electron accelerators, optoelectronic devices, electronic materials, ray tubes, crystal oscillators, laser equipment, ion implanters, ion etchers, chemical vapor deposition machines, plasma enhanced chemical vapor deposition machines, physical vapor deposition machines, molecular beam epitaxy equipment, integrated circuit packaging, etc., medium and high vacuum technology is widely used.

[0003] In order to ensure the accuracy and stability of the vacuum value in the chamber, it is necessary to accurately and quickly measure the vacuum value in the chamber. Since different types of vacuum gauges have different measurement ranges, some are suitable for high vacuum environment, and some are suitable for low vacuum environment. When the process chamber uses a wide range of vacuum values, a single vacuum gauge cannot achieve accurate and rapid acquisition of vacuum values in the entire use range.

[0004] In addition, since most of the current vacuum gauges use analog output mode, the voltage output of the vacuum gauge is very small, and the measured voltage value is very similar when the vacuum gauge is disconnected. The current conventional acquisition method cannot be well handled. SUMMARY

[0005] The present application aims to at least solve one of the problems in the related art. To this end, the purpose of the present application is to provide a multi-range vacuum gauge data acquisition method, which can realize the acquisition of vacuum values in a large-span application scenario, ensure high acquisition accuracy, and the method can realize automatic detection of disconnection and better handle the scenarios of small voltage output of the vacuum gauge and vacuum gauge disconnection.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] A multi-range vacuum gauge data acquisition method for measuring the vacuum degree of a vacuum chamber includes the following steps:

[0008] Step S1: setting the measurement range of the first vacuum gauge and the second vacuum gauge, and the overlapping measurement range of the first vacuum gauge and the second vacuum gauge; wherein the measurement range of the first vacuum gauge is greater than the measurement range of the second vacuum gauge, the precision guarantee interval of the first vacuum gauge is (X%*the measurement range of the first vacuum gauge)~the measurement range of the first vacuum gauge, the precision guarantee interval of the second vacuum gauge is (X%*the measurement range of the second vacuum gauge)~the measurement range of the second vacuum gauge, and the precision interval of the first vacuum gauge and the second vacuum gauge is (X%*the measurement range of the second vacuum gauge)~the measurement range of the first vacuum gauge; X is less than 100;

[0009] Step S2: acquiring the voltage measurement value V1 of the first vacuum gauge and the voltage measurement value V2 of the second vacuum gauge respectively;

[0010] Step S3: outputting the result value of the multi-range vacuum gauge data acquisition; which includes the following steps:

[0011] Step S31: judging whether the voltage measurement value V1 exceeds the upper limit value V1max of the first vacuum gauge, if yes, outputting the vacuum value Output as the measurement value of the first vacuum gauge and performing the over upper limit alarm Ex_Max; wherein the upper limit value V1max of the first vacuum gauge is the range value of the first vacuum gauge;

[0012] Step S32: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge and the voltage measurement value V2 exceeds the upper limit value V2max of the second vacuum gauge, judging whether the voltage measurement value V1 exceeds the overlapping upper limit Volu of the two vacuum gauges, if yes, outputting the measurement value of the first vacuum gauge and clearing the alarm signal, if not, converging the output vacuum value Output to the position of the upper limit value of the second vacuum gauge through the overlapping algorithm 1; wherein the upper limit value V2max of the second vacuum gauge is the range value of the second vacuum gauge; the overlapping algorithm 1 is:

[0013] Output=V2max+V1*(Volu-V2max) / Volu

[0014] Step S33: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the upper limit value V2max of the second vacuum gauge, and is greater than the overlapping lower limit Voll of the two vacuum gauges, converging the output vacuum value Output to the measurement value of the second vacuum gauge through the overlapping algorithm 2; wherein the overlapping algorithm 2 is:

[0015] Oupput=(V2max-V2)*V2 / (V2max-Voll)+(V2-Voll) / (V2max-Voll)*V1’

[0016] wherein V1' = MAX(MIN(V2max, V1), Vol1)

[0017] Step S34: output the measurement value of the second vacuum gauge when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, and the voltage measurement value V2 is not greater than the lower limit value Vol1 of the two vacuum gauges and is greater than the lower limit value V2min of the second vacuum gauge;

[0018] Step S35: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, and the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, determine the open-circuit shielding signal of the first vacuum gauge and the second vacuum gauge; if the open-circuit shielding signal of the second vacuum gauge is 1, output the measurement value of the second vacuum gauge and perform an over-lower-limit alarm Ex_Min.

[0019] Step S36: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, and the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, determine the open-circuit shielding signal of the first vacuum gauge and the second vacuum gauge; if the open-circuit shielding signal of the second vacuum gauge is 0, and the open-circuit shielding signal of the first vacuum gauge is 1, output the measurement value of the first vacuum gauge and perform an over-lower-limit alarm; if the open-circuit shielding signal of the second vacuum gauge is 0, and the open-circuit shielding signal of the first vacuum gauge is 0, output a value of -1 and perform an open-circuit alarm.

[0020] Further, the measurement range of the first vacuum gauge is a value between 2 times and 10 times the measurement range of the second vacuum gauge.

[0021] Further, the X is less than 50.

[0022] Further, the X is 10.

[0023] Further, the multi-range vacuum gauge data acquisition method further comprises a step S4 of shielding the open-circuit of the two-range vacuum gauges; the step S4 comprises:

[0024] adding a vacuum pressure switch on the vacuum cavity, setting a pressure determination limit value BRK_CHK1 of the vacuum degree of the first vacuum gauge, and setting a pressure determination limit value BRK_CHK2 of the vacuum degree of the first vacuum gauge; when the vacuum pressure switch has a signal, it indicates that the vacuum cavity is in a vacuum state, at which time the open-circuit signals of the first vacuum gauge and the second vacuum gauge are shielded; and

[0025] When the vacuum pressure switch is not used, or the vacuum pressure switch is higher than the pressure determination limit value of the vacuum degree, the values collected by the first vacuum gauge and the second vacuum gauge are compared with the broken line shielding voltage, and when the values of the first vacuum gauge and the second vacuum gauge are greater than the broken line shielding voltage, the broken line shielding signal of the corresponding vacuum gauge is set to 1.

[0026] The technical solution provided by the embodiment of the application can realize the collection of the vacuum value in a large-span application scenario, ensure high collection accuracy, and realize automatic detection of a broken line, and better handle the scenario in which the voltage output of the vacuum gauge is small and the vacuum gauge is broken. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without creative labor.

[0029] Figure 1 Flowchart of the data collection method of the two-range vacuum gauge of the application

[0030] Figure 2 Output data distribution diagram of the two-range vacuum gauge in the embodiment of the application

[0031] Figure 3 Broken line shielding flowchart of the two-range vacuum gauge in the embodiment of the application

[0032] Figure 4 And Figure 5 The effect diagram of using the overlapping algorithm 1 and the overlapping algorithm 2 (two integrated algorithms) in the embodiment of the application is shown

[0033] Explanation of abbreviations in the drawings:

[0034] V1--first vacuum gauge measurement value

[0035] V2--second vacuum gauge measurement value

[0036] Output--output vacuum value

[0037] Volu--upper limit of overlapping of two vacuum gauges

[0038] Voll--lower limit of overlapping of two vacuum gauges

[0039] V2max - upper limit of the second vacuum gauge

[0040] V2min - lower limit of the second vacuum gauge

[0041] V1max - upper limit of the first vacuum gauge

[0042] V1min - lower limit of the first vacuum gauge

[0043] ALM_Out - output alarm information

[0044] Ex_Max - output value exceeding the upper limit

[0045] Ex_Min - output value exceeding the lower limit

[0046] BRK_CHK1 - first vacuum gauge breakage shielding voltage

[0047] BRK_CHK2 - second vacuum gauge breakage shielding voltage

[0048] Overlap algorithm 1: Output = V2max + V1*(Volu-V2max) / Volu

[0049] Overlap algorithm 2:

[0050] Output = (V2max-V2)*V2 / (V2max-Volu) + (V2-Volu)*V1 / (V2max-Volu) DETAILED DESCRIPTION

[0051] In order to have a more clear understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the accompanying drawings. In the following description, it should be understood that the features defined as "first", "second", "third" and the like can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0052] In the following description, specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, mechanisms, circuits and processes are omitted so as not to obscure the description of the present application with unnecessary detail.

[0053] Please refer to Figure 1 and Figure 2 , Figure 1 is a flowchart of the data acquisition method of the two-range vacuum gauge of the present application;Figure 2 This is a schematic diagram showing the data distribution of two range vacuum gauges in an embodiment of the present invention. This multi-range vacuum gauge data acquisition method is used for measuring the vacuum level of a vacuum chamber.

[0054] Those skilled in the art will understand that the lower the voltage value of the analog voltage signal output by the vacuum gauge, the smaller the vacuum value collected, indicating a higher degree of vacuum.

[0055] like Figure 1 As shown, the multi-range vacuum gauge data acquisition method may include the following steps:

[0056] Step S1: Set the measurement range of the first vacuum gauge and the second vacuum gauge, and the overlapping measurement range of the first vacuum gauge and the second vacuum gauge; wherein, the measurement range of the first vacuum gauge is larger than the measurement range of the second vacuum gauge, the accuracy guarantee range of the first vacuum gauge is (X% * first vacuum gauge range) to the first vacuum gauge range, the accuracy guarantee range of the second vacuum gauge is (X% * second vacuum gauge range) to the second vacuum gauge range; the accuracy range of the first vacuum gauge and the second vacuum gauge is (X% * second vacuum gauge range) to the first vacuum gauge range; X is less than 100; preferably, X is less than 50, for example, X is 10.

[0057] In an embodiment of the present invention, the measurement range of the first vacuum gauge is greater than the measurement range of the second vacuum gauge (e.g., Figure 2 As shown in the figure, Volu is the upper limit of the overlap between the two vacuum gauges, Voll is the lower limit of the overlap between the two vacuum gauges, V2max is the upper limit of the second vacuum gauge, V2min is the lower limit of the second vacuum gauge, V1max is the upper limit of the first vacuum gauge, and V1min is the lower limit of the first vacuum gauge.

[0058] Generally, for example, the measurement range of the first vacuum gauge can be 10 times that of the second vacuum gauge. The accuracy guarantee range of the first vacuum gauge is (10% * first vacuum gauge range) to the first vacuum gauge range, and the accuracy guarantee range of the second vacuum gauge is (10% * true second vacuum gauge) to the second vacuum gauge range. Therefore, the accuracy range guaranteed by the two vacuum gauges in the diagram is (10% * second vacuum gauge) to the first vacuum gauge range. If a wider measurement range is required, a vacuum gauge with a smaller range needs to be added on top of this.

[0059] Step S2: Obtain the voltage measurement value V1 of the first vacuum gauge and the voltage measurement value V2 of the second vacuum gauge, respectively.

[0060] Step S3: Output the data acquisition results of the multi-range vacuum gauge; this includes the following steps:

[0061] Step S31: judging whether the voltage measurement value V1 exceeds the upper limit value V1max of the first vacuum gauge, if yes, outputting the vacuum value Output as the measurement value of the first vacuum gauge and performing the over upper limit alarm Ex_Max; wherein the upper limit value V1max of the first vacuum gauge is the range value of the first vacuum gauge;

[0062] Step S32: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge and the voltage measurement value V2 exceeds the upper limit value V2max of the second vacuum gauge, judging whether the voltage measurement value V1 exceeds the overlapping upper limit Volu of the two vacuum gauges, if yes, outputting the measurement value of the first vacuum gauge and clearing the alarm signal; if no, converging the output vacuum value Output to the position of the upper limit value of the second vacuum gauge through the overlapping algorithm 1; wherein the upper limit value V2max of the second vacuum gauge is the range value of the second vacuum gauge; the overlapping algorithm 1:

[0063] Output = V2max + V1*(Volu-V2max) / Volu

[0064] Step S33: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the upper limit value V2max of the second vacuum gauge and is greater than the overlapping lower limit Voll of the two vacuum gauges, converging the output vacuum value Output to the measurement value of the second vacuum gauge through the overlapping algorithm 2; wherein the overlapping algorithm 2:

[0065] Oupput = (V2max-V2)*V2 / (V2max-Voll) + (V2-Voll) / (V2max-Voll)*V1’

[0066] wherein V1’ = MAX(MIN(V2max, V1), Voll)

[0067] Step S34: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 is not greater than the overlapping lower limit Voll of the two vacuum gauges and is greater than the lower limit value V2min of the second vacuum gauge, outputting the measurement value of the second vacuum gauge;

[0068] Step S35: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, judging the broken line shielding signal of the first vacuum gauge and the second vacuum gauge; if the broken line shielding signal of the second vacuum gauge is 1, outputting the measurement value of the second vacuum gauge and performing the over lower limit alarm Ex_Min;

[0069] Step S36: the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, and the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, the broken line shielding signal of the first vacuum gauge and the second vacuum gauge is judged; if the broken line shielding signal of the second vacuum gauge is 0 and the broken line shielding signal of the first vacuum gauge is 1, the measurement value of the first vacuum gauge is outputted and an over-limit alarm Ex_Max is performed; if the broken line shielding signal of the second vacuum gauge is 0 and the broken line shielding signal of the first vacuum gauge is 0, the output value is -1 and a broken line alarm is performed.

[0070] Please refer to Figure 3 , Figure 3 The figure is a broken line shielding flowchart of two range vacuum gauges in the embodiment of the present application. As shown in the figure, the multi-range vacuum gauge data acquisition method further comprises a step S4 of broken line shielding of two range vacuum gauges; the step S4 comprises: Figure 3

[0071] A vacuum pressure switch is added on the vacuum cavity, a pressure determination limit value BRK_CHK1 of the vacuum degree of the first vacuum gauge is set, and a pressure determination limit value BRK_CHK2 of the vacuum degree of the first vacuum gauge is set; when the vacuum pressure switch has a signal, it indicates that the vacuum cavity is in a vacuum state, at this time, the broken line signals of the first vacuum gauge and the second vacuum gauge are shielded; and

[0072] Without using the vacuum gauge pressure switch or the vacuum pressure switch being higher than the pressure determination limit value of the vacuum degree, the values collected by the first vacuum gauge and the second vacuum gauge are compared with the broken line shielding voltage, when the values of the first vacuum gauge and the second vacuum gauge are greater than the broken line shielding voltage, the broken line shielding signal of the corresponding vacuum gauge is set to 1.

[0073] Please refer to Figs. 4 and Figure 5 , Figure 4 and Figure 5 The figure is an effect schematic diagram of the embodiment of the present application by using overlapping algorithm 1 and by using overlapping algorithm 2 (two integrated algorithms). As shown in the figure, the value of the first vacuum gauge is higher than the value of the second vacuum gauge in the overlapping area. As shown in the figure, the value of the first vacuum gauge is lower than the value of the second vacuum gauge in the overlapping area. Figure 4 Figure 5 That is to say, in the above two scenarios, the output value of the vacuum gauge will quickly converge to the vacuum value of the second vacuum gauge when the value of the second vacuum gauge is valid.

[0074] That is to say, in the above two scenarios, the output value of the vacuum gauge will quickly converge to the vacuum value of the second vacuum gauge when the value of the second vacuum gauge is valid.

[0075] ​​In summary, by the data acquisition method of the multi-range vacuum gauge, the continuous change of the two vacuum gauge values can be realized, the phenomenon that the two vacuum gauge values cannot be distinguished due to the large difference in the overlapping measurement region or the value jump can be avoided, in addition, the output value converges quickly to the value of the small range vacuum gauge in the range switching region, and the precision of the output data can be ensured. In addition, the use of the broken line shielding signal in the output data calculation can effectively distinguish the high vacuum signal and the interference signal when the line is broken, and the validity of the data in the high vacuum state can be effectively ensured.

[0076] It can be understood that the above embodiments only express the preferred embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application; it should be pointed out that for ordinary skilled in the art, the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which belong to the protection scope of the present application; therefore, any equivalent transformation and modification within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A multi-range vacuum gauge data acquisition method for measuring the vacuum level of a vacuum cavity, characterized in that, The method comprises the following steps: Step S1: setting the measurement range of the first vacuum gauge and the second vacuum gauge, and the overlapping measurement range of the first vacuum gauge and the second vacuum gauge; wherein the measurement range of the first vacuum gauge is greater than the measurement range of the second vacuum gauge, the precision guarantee interval of the first vacuum gauge is (X%*the measurement range of the first vacuum gauge)~the measurement range of the first vacuum gauge, the precision guarantee interval of the second vacuum gauge is (X%*the measurement range of the second vacuum gauge)~the measurement range of the second vacuum gauge, and the precision interval of the first vacuum gauge and the second vacuum gauge is (X%*the measurement range of the second vacuum gauge)~the measurement range of the first vacuum gauge; X is less than 100; Step S2: acquiring the voltage measurement value V1 of the first vacuum gauge and the voltage measurement value V2 of the second vacuum gauge respectively; Step S3: outputting the result value of the multi-range vacuum gauge data acquisition; which comprises the following steps: Step S31: judging whether the voltage measurement value V1 exceeds the upper limit value V1max of the first vacuum gauge, if yes, outputting the vacuum value Output as the measurement value of the first vacuum gauge and performing the over-upper-limit alarm Ex_Max; wherein the upper limit value V1max of the first vacuum gauge is the range value of the first vacuum gauge; Step S32: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge and the voltage measurement value V2 exceeds the upper limit value V2max of the second vacuum gauge, judging whether the voltage measurement value V1 exceeds the overlapping upper limit Volu of the two vacuum gauges, if yes, outputting the measurement value of the first vacuum gauge and clearing the alarm signal, if no, converging the output vacuum value Output to the position of the upper limit value of the second vacuum gauge through the overlapping algorithm 1; wherein the upper limit value V2max of the second vacuum gauge is the range value of the second vacuum gauge; the overlapping algorithm 1 is: Output=V2max+V1*(Volu-V2max) / Volu Step S33: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the upper limit value V2max of the second vacuum gauge and is greater than the overlapping lower limit Voll of the two vacuum gauges, converging the output vacuum value Output to the measurement value of the second vacuum gauge through the overlapping algorithm 2; wherein the overlapping algorithm 2 is: Oupput=(V2max-V2)*V2 / (V2max-Voll)+(V2-Voll) / (V2max-Voll)*V1’ Wherein, V1’=MAX(MIN(V2max, V1), Voll) Step S34: when the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge and the voltage measurement value V2 is not greater than the overlapping lower limit Voll of the two vacuum gauges and is greater than the lower limit value V2min of the second vacuum gauge, outputting the measurement value of the second vacuum gauge. Step S35: the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, the broken line shielding signal of the first vacuum gauge and the second vacuum gauge is judged; if the broken line shielding signal of the second vacuum gauge is 1, the measurement value of the second vacuum gauge is outputted and an over lower limit alarm Ex_Min is given; Step S36: the voltage measurement value V1 does not exceed the upper limit value V1max of the first vacuum gauge, the voltage measurement value V2 does not exceed the lower limit value V2min of the second vacuum gauge, the broken line shielding signal of the first vacuum gauge and the second vacuum gauge is judged; if the broken line shielding signal of the second vacuum gauge is 0 and the broken line shielding signal of the first vacuum gauge is 1, the measurement value of the first vacuum gauge is outputted and an over lower limit alarm is given; if the broken line shielding signal of the second vacuum gauge is 0 and the broken line shielding signal of the first vacuum gauge is 0, the output value is -1 and a broken line alarm is given.

2. The multirange gauge data acquisition method of claim 1, wherein, The measurement range of the first vacuum gauge is a value between 2 times and 10 times of the measurement range of the second vacuum gauge.

3. The multirange gauge data acquisition method of claim 1, wherein, The X is less than 50.

4. The multirange gauge data acquisition method of claim 3, wherein, The X is 10.

5. The method of data acquisition for a multirange gauge as claimed in any one of claims 1 to 4, wherein, The step S4 of the broken line shielding of the two range vacuum gauges further comprises: A vacuum pressure switch is added on the vacuum cavity, the pressure determination limit value BRK_CHK1 of the vacuum degree of the first vacuum gauge is set, the pressure determination limit value BRK_CHK2 of the vacuum degree of the first vacuum gauge is set; when the vacuum pressure switch has a signal, it indicates that the vacuum cavity is in a vacuum state, at this time, the broken line signals of the first vacuum gauge and the second vacuum gauge are shielded; and Without using the vacuum gauge pressure switch or the vacuum pressure switch is higher than the pressure determination limit value of the vacuum degree, the values collected by the first vacuum gauge and the second vacuum gauge are compared with the broken line shielding voltage, when the values of the first vacuum gauge and the second vacuum gauge are greater than the broken line shielding voltage, the broken line shielding signal of the corresponding vacuum gauge is set to 1.

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