JP2009009786A - Mass spectroscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the release of a vacuum atmosphere caused by the temporary stop of a vacuum pump at program updating, CPU runaway or the like. <P>SOLUTION: When a CPU 31 updates a program by the direction of a personal computer 40 at program updating, a reset request signal is outputted which a reset logic circuit 34 receives and generates a self-resetting signal to return it to the CPU 31. By this, the CPU 31 is reset and restarted. Even during this time, the vacuum pump 22 continues its operation by the setting of a vacuum pump logic circuit 36, the CPU 31 initialized by restarting reads status information showing the operation state of the vacuum pump 22, and starts to control the vacuum pump 22 from that state again as needed. Even in the case that a reset switch 35 is operated at the CPU runaway or the like, the CPU 31 is reset and restarted in a similar route. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mass spectrometer, and more particularly to control of a mass spectrometer.

  In the liquid chromatograph mass spectrometer, the configuration of a multistage differential exhaust system is adopted so that ionization is performed under a substantially atmospheric pressure atmosphere and mass separation and ion detection are performed under a high vacuum atmosphere. In order to perform such multistage differential pumping, a plurality of vacuum pumps such as a rotary pump and a turbo molecular pump are used, and the operation of these vacuum pumps is controlled by a control unit centering on the CPU.

  In general, a mass spectrometer takes a long time from when power is turned on until a vacuum housing in which a mass analyzer and the like are disposed is sufficiently evacuated and ready for analysis. Therefore, for example, even if a certain analysis is completed and there is time before the next analysis, the power supply of the apparatus is almost always turned on without being turned off. That is, in general, the power supply is almost always turned on except when the operation is stopped for a long period of time, and the inside of the vacuum housing is often kept evacuated (see, for example, Patent Document 1).

  By the way, the CPU operates in accordance with a program stored in advance in a ROM or the like, but the update of such a program is performed at a relatively high frequency. When updating such a program, it is necessary to perform reset and restart in order to perform an operation according to the updated program. In addition, as is well known, the CPU may run out of control, and in such a case, for example, the reset switch may be manually reset and initialized by restarting to return to the normal state. Is called.

  In the conventional mass spectrometer, when the program is updated as described above or when the CPU is out of control, the CPU is reset / restarted by turning the power off → off or turning on the reset switch. In that case, since the control for all the control target elements is once initialized, the operation of the vacuum pump is also temporarily stopped. Therefore, the vacuum atmosphere in the vacuum housing is released, and it takes a certain amount of time until the degree of vacuum returns to the original state after the CPU is started and the operation of the vacuum pump is resumed. Therefore, there is a problem that analysis cannot be performed immediately and analysis efficiency is deteriorated. Moreover, if the frequency of starting and stopping the vacuum pump is high, the life of the vacuum pump may be shortened.

JP 2000-36283 A

  The present invention has been made to solve the above-described problems, and the object of the present invention is to enable a program update or a CPU runaway without releasing the vacuum atmosphere in the vacuum housing. An object of the present invention is to provide a mass spectrometer.

The present invention, which has been made to solve the above problems, includes one or more vacuum pumps that maintain a vacuum inside a vacuum housing in which a mass analyzer and an ion detector are disposed, and various types including the vacuum pump. A control unit that controls the operation of the control target element, the control unit,
a) a CPU with a storage unit storing a program;
b) The vacuum pump is started and stopped in response to an instruction from the CPU, and the vacuum pump is maintained so as to maintain an operation state corresponding to the most recent instruction when there is no instruction from the CPU. A pump drive control circuit for driving;
c) In response to an instruction from the CPU or a manual operation by the user, a reset signal for resetting and restarting the CPU is generated and given to the CPU. A reset signal generation circuit for providing a reset signal to the pump drive control circuit;
It is characterized by having.

  Here, a memory element that can rewrite information electrically, such as a flash ROM, can be used as the storage unit.

  The reset signal generation circuit, for example, receives a pulse signal as an instruction from the CPU, and generates a predetermined reset signal in response to the pulse signal, and conducts or disconnects a signal line by operating a mechanical switch. In response, a logic circuit that generates a predetermined reset signal and a logic circuit that monitors a power supply voltage and generates a predetermined reset signal when the voltage exceeds a predetermined threshold are independently or partly provided. It can be set as the structure provided also as combined.

  In the mass spectrometer according to the present invention, for example, when a program update instruction and program data are transmitted from an external control computer to the control unit, the CPU updates the program stored in the storage unit. After the update, a reset request instruction is issued to the reset signal generation circuit. In response to this, the reset signal generation circuit sends a reset signal to the CPU, and the CPU is reset and restarted. During this time, the pump drive control circuit continues to operate in accordance with instructions given from the CPU before that, and therefore continues to operate as long as the vacuum pump is operating. Similarly, when the user operates the reset switch due to the runaway of the CPU, the CPU is reset and restarted while the operation of the vacuum pump is continued, and the CPU returns to the normal state. On the other hand, since the reset signal is given not only to the CPU but also to the pump drive control circuit when the power of the apparatus is turned on, the vacuum pump operates from the initial setting state. Thereby, normal evacuation can be performed.

  In general, a CPU has a built-in or attached watchdog timer. The watchdog timer detects a CPU runaway and automatically resets it without waiting for the user's reset switch operation. Processing for restart can be performed. Also at this time, the operation of the vacuum pump can be continued.

  Therefore, according to the mass spectrometer of the present invention, since the vacuum pumping operation of the vacuum pump is continued even when the program is updated or the CPU runaway is dealt with, the vacuum atmosphere in the vacuum housing is not released. The next analysis can be performed immediately after the CPU is restarted. In addition, since the vacuum pump is not turned off and on when the program is updated or the CPU runs out of control, the number of times the vacuum pump is turned on and off can be reduced, thereby extending the life of the vacuum pump and improving the reliability of the device. be able to.

  Note that when the CPU is reset / restarted, the information in the internal memory is basically cleared, so the state of the vacuum pump (either in operation or stopped) is unknown immediately after restarting. Therefore, in the mass spectrometer according to the present invention, the pump drive control circuit has an information holding circuit for holding status information indicating the state of the vacuum pump at that time, and the CPU is configured to execute the reset / restart after the reset. It is preferable that the status information held in the information holding circuit is read, the state of the vacuum pump is grasped, and the subsequent control is performed. As a result, the operation control of the vacuum pump can be normally performed without resetting the pump drive control circuit when the CPU is reset and restarted.

  Hereinafter, an embodiment of an LC / MS to which a mass spectrometer according to the present invention is applied will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of the LC / MS of this embodiment.

  In the LC unit 1, the liquid feeding unit 3 sucks the mobile phase from the mobile phase container 2 and feeds it to the column 5 while maintaining a constant liquid feeding amount. When a sample is injected into the mobile phase at a predetermined timing by an injector 4 provided in front of the column 5, the sample is introduced into the column 5 on the mobile phase. Various components (compounds) in the sample are separated while passing through the column 5 and are eluted from the outlet of the column 5 with different holding times and introduced into the mass spectrometer 10.

In the mass spectrometer 10, the sample solution is sprayed from the ESI nozzle 12 into the ionization chamber 11, which is a substantially atmospheric pressure atmosphere, and component molecules in the sample solution are ionized. The generated ions are sent to the first intermediate vacuum chamber 14 through the heating pipe 13. The first intermediate vacuum chamber 14 is maintained in a low vacuum atmosphere (for example, about 10 ² [Pa]) by being evacuated by the rotary pump 221. The ions introduced into the first intermediate vacuum chamber 14 are fed into the second intermediate vacuum chamber 17 through the orifice at the top of the skimmer 16 while being converged by the first ion lens 15. The second intermediate vacuum chamber 17 is maintained in a medium vacuum atmosphere (for example, about 10 ⁻¹ to 10 ⁻² [Pa]) by being evacuated by the turbo molecular pump 222 and introduced into the second intermediate vacuum chamber 17. The ions are fed into the analysis chamber 19 while being converged by the octopole-type second ion lens 18.

The analysis chamber 19 is maintained in a high vacuum atmosphere (for example, about 10 ⁻³ to 10 ⁻⁴ [Pa]) by being evacuated by another turbo molecular pump 223, and has a specific mass (strictly, mass to charge ratio m / Only ions having z) pass through the space in the long axis direction of the quadrupole mass filter 20, and ions having other masses diverge midway. Then, the ions that have passed through the quadrupole mass filter 20 reach an ion detector 21 based on, for example, a combination of a conversion dynode and a photomultiplier tube, and the ion detector 21 outputs an ion intensity signal corresponding to the amount of ions reached. To do. This output signal is input to a data processing unit (not shown), where a mass spectrum, a mass chromatogram, or a total ion chromatogram is created, and further qualitative / quantitative analysis is performed.

  As described above, the mass spectrometer 10 has a configuration of a multistage differential exhaust system in which the degree of vacuum is increased stepwise between the ionization chamber 11 which is a substantially atmospheric pressure atmosphere and the analysis chamber 19 which is a high vacuum atmosphere. Yes. Here, it can be considered that the intermediate vacuum chambers 14 and 17 and the analysis chamber 19 excluding the ionization chamber 11 having a substantially atmospheric pressure atmosphere are constituted by the vacuum housing in the present invention.

  FIG. 2 is a block diagram of the main part of the LC / MS control system of this embodiment. The personal computer (PC) 40 is equipped with control software (for example, LCMSsolution manufactured by Shimadzu Corporation) that can set analysis conditions using a GUI, and performs analysis by communicating with the main body control unit 30. Various instructions related to. A main body control unit 30 incorporated in the apparatus includes a CPU 31, a program ROM 32, a reset logic circuit (corresponding to a reset signal generation circuit in the present invention) 34, a vacuum pump control logic circuit (corresponding to a pump drive control circuit in the present invention) 36, A control logic circuit 37 and the like are included.

  The vacuum pump control logic circuit 36 has a function of holding a signal instructing on / off of the vacuum pump (the rotary pump 221 and the turbo molecular pumps 222 and 223) 22 supplied from the CPU 31 and outputting a drive signal based on the signal. And a function (for example, a register) for holding the on / off state of the vacuum pump 22 at that time as status information. The reset logic circuit 34 is a first logic circuit that generates a self-reset signal when it receives a reset request signal given from the CPU 31 and when the reset switch 35 is turned on, and monitors the power supply voltage so that the voltage is predetermined. And a second logic circuit that generates a reset signal when the threshold value exceeds a threshold value, a self-reset signal from the first logic circuit is provided to the CPU 31, while a reset signal from the second logic circuit is a reset signal at power-on. Are given in common to the CPU 31, the vacuum pump control logic circuit 36 and the control logic circuit 37.

  The CPU 31 is provided with (or built in) a watch dog timer 33. When the watch dog timer 33 detects that the CPU 31 is out of control, the watch dog timer 33 issues a reset request signal and the reset logic circuit 34 outputs a self-reset signal. It returns to CPU31. Further, the CPU 31 sends a CPU clear signal so that the vacuum pump control logic circuit 36 and the control logic circuit 37 can be independently initialized independently of the power-on reset signal. The control logic circuit 37 is connected to a control object other than the vacuum pump 22 in the present apparatus, specifically, a heater provided for temperature control of each part, the ion lenses 16 and 18, the quadrupole mass filter 20, and the like. It is a circuit for controlling the operation of a power supply unit for applying a predetermined voltage.

  Here, the vacuum pump 22 and the other control objects are separated from each other because the latter can be restored to the original state in a relatively short time after the operation is resumed even if the operation is temporarily stopped. That is, it takes time for the vacuum pump 22 to return to the original state when the vacuum atmosphere is released, and the vacuum pump 22 does not want to be turned on / off frequently.

Next, a characteristic operation centering on the main body control unit 30 will be described.
(1) When updating the program When the vacuum pump 22 is on (but analysis is not executed), if there is a need to update the program stored in the program ROM 32, an update instruction and program are sent from the personal computer 40. Data is sent. In response to this instruction, the CPU 31 writes the received program in the program ROM 32. When the writing is completed, the CPU 31 sends a reset request signal to the reset logic circuit 34, and in response to this, the reset logic circuit 34 outputs a self-reset signal to the CPU 31. The CPU 31 receives this self-reset signal and executes reset / restart. That is, the CPU 31 once shuts off the power and restarts according to the updated program. At this time, data in the internal memory and registers are cleared.

  Even when the CPU 31 is reset / restarted, the vacuum pump 22 continues to operate according to the settings of the vacuum pump control logic circuit 36, so the vacuum state in the analysis chamber 19 and the like remains unchanged. When the CPU 31 is restarted, the internal memory of the CPU 31 is initialized as described above, so the operating state of the vacuum pump 22 is unknown. Therefore, the CPU 31 accesses the vacuum pump control logic circuit 36, reads status information indicating the on / off state of the vacuum pump 22, and sets it in the internal memory. Thereafter, necessary vacuum system control operations such as on / off of the vacuum pump 22 are started from that state.

  When the CPU 31 is restarted, the CPU clear signal B is output so that the control logic circuit 37 is initialized. Thereby, control objects other than the vacuum pump 22 are controlled from the initial state. Of course, after the CPU 31 reads the status information of the vacuum pump 22 and starts its control, if it is desired to initialize the vacuum pump control logic circuit 36 as necessary, the CPU clear signal A may be output.

(2) At the time of manual reset of the CPU When the user turns on the reset switch 35, the reset logic circuit 34 outputs a self-reset signal to the CPU 31 in the same manner as when the reset request signal is received from the CPU 31. Accordingly, although the CPU 31 is restarted as in the program update described above, the operation of the vacuum pump 22 is continued, and after the CPU 31 is restarted, the control operation of the vacuum pump 22 is performed again.

(3) At the time of automatic reset due to CPU runaway or the like The operation of the CPU 31 is monitored by the watchdog timer 33, and if a problem occurs in the execution of the program, a reset request signal is issued as described above. As a result, the CPU 31 is reset and restarted as in the case of the manual reset, and the operation of the vacuum pump 22 is continued.

(4) When the power of the apparatus is turned on When the power of the mass spectrometer is turned on, the power supply voltage detection function in the reset logic circuit 34 is activated to output a reset signal when the power is turned on. The CPU 31, the vacuum pump control logic circuit 36, and the control logic circuit 37 all start to operate from the initial state.

  In the above description, the reset logic circuit 34 is a hardware circuit, but may be a circuit using an inexpensive CPU different from the CPU 31.

  Moreover, since the said Example is an example of this invention, even if it changes suitably, amends, and is added in the range of the meaning of this invention, it is clear that it is included by the claim of this application. For example, although the said Example demonstrated the example which applied the mass spectrometer which concerns on this invention to LC / MS, it is applicable also to GC / MS and another mass spectrometer. The present invention can be applied not only to a quadrupole mass spectrometer but also to any type of mass spectrometer that performs mass analysis in a vacuum atmosphere, such as a time-of-flight type or an ion trap type.

The whole block diagram of one Example of LC / MS to which the mass spectrometer which concerns on this invention is applied. The block block diagram of the principal part of the control system of LC / MS of a present Example.

Explanation of symbols

22 ... Vacuum pump 221 ... Rotary pump 222, 223 ... Turbo molecular pump 30 ... Main body control unit 31 ... CPU
32 ... Program ROM
33 ... Watchdog timer 34 ... Reset logic circuit 35 ... Reset switch 36 ... Vacuum pump control logic circuit 36
37 ... Control logic circuit 40 ... Personal computer

Claims (2)

Including one or more vacuum pumps that maintain a vacuum inside the vacuum housing in which the mass analyzer and the ion detector are disposed, and a control unit that controls the operation of various control target elements including the vacuum pump. In the mass spectrometer, the controller is
a) a CPU with a storage unit storing a program;
b) The vacuum pump is started and stopped in response to an instruction from the CPU, and the vacuum pump is maintained so as to maintain an operation state corresponding to the most recent instruction when there is no instruction from the CPU. A pump drive control circuit for driving;
c) In response to an instruction from the CPU or a manual operation by the user, a reset signal for resetting and restarting the CPU is generated and given to the CPU. A reset signal generation circuit for providing a reset signal to the pump drive control circuit;
A mass spectrometer comprising:   The pump drive control circuit has an information holding circuit for holding status information indicating the state of the vacuum pump at that time, and the CPU displays the status information held in the information holding circuit after reset / restart. The mass spectrometer according to claim 1, wherein the control is performed after reading and grasping the state of the vacuum pump.

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