JP6160358B2 - NMR measurement system - Google Patents

Description

  The present invention relates to an NMR (Nuclear Magnetic Resonance) measurement system, and more particularly to an NMR measurement system having an auto-tuning function.

  The NMR measurement system is a system for observing an NMR signal, that is, a nuclear magnetic resonance signal from an observation nucleus in a sample. The NMR measurement system includes, for example, a spectrometer including a transmitter and a receiver, an NMR probe including an NMR detection circuit, a relay device provided between the spectrometer and the NMR probe, a system controller, and the like. The NMR detection circuit in the NMR probe includes a variable capacitor for tuning (for tuning), a variable capacitor for matching (for matching), and the like, in addition to a transmission / reception coil for NMR detection.

Prior to sample measurement, adjustment of the NMR signal detection circuit, that is, tuning in a broad sense, is performed. In this case, the level of the reflected wave (return loss level) generated when a transmission signal is sent to the NMR probe is minimized. Thus, the capacitances of the tuning variable capacitor and the matching variable capacitor are optimized. In order to perform such work, for example, a relay device is provided with a circuit for detecting a return loss level and a display for displaying the level (see, for example, Patent Document 1).

  As a tuning method of the NMR detection circuit, there are a manual method and an auto method (auto tuning method). The former is a method of performing tuning manually while observing the return loss level, and the latter is a method of automatically searching for and setting a tuning condition that minimizes the return loss level.

  As disclosed in Patent Document 2, in the latter auto-tuning, for example, an auto-tuning unit configured as an external unit is connected to the NMR probe. Specifically, the NMR probe is provided with a plurality of internal shafts and a plurality of connection ports forming ends thereof for operating the tuning variable capacitor and the matching variable capacitor from the outside. The working ends (tips) of a plurality of external shafts (flexible shafts) are connected. A drive source such as a pulse motor is connected to the rear ends of the plurality of flexible shafts. Using these drive sources, for example, a plurality of different capacitance value sets are sequentially set on a trial basis, and the return loss level is individually detected under the circumstances. Each capacitance value set includes a tuning capacitance value (tuning dial value) and a matching capacitance value (matching dial value). An optimal capacity value set is calculated by executing a predetermined function calculation based on the plurality of return loss levels obtained as described above. The optimum capacitance set is set for the tuning variable capacitor and the matching variable capacitor. Then, the NMR measurement is actually performed. As the variable capacitor, for example, a multi-turn variable capacitor having an operation range of about 10 rotations is used.

Japanese Patent No. 4037626 JP 2003-185725 A

  When auto-tuning is performed, if there is any defect on the path from the driving source to the variable capacitor, particularly on the path between the driving source and the internal shaft, it is naturally impossible to perform tuning correctly. Such deficiencies include, for example, disengagement of the external shaft, idle rotation of the external shaft, rotational deviation (slip) between the external shaft and the internal shaft, and erroneous connection of the external shaft. In order to perform auto-tuning accurately and quickly, it is necessary for the user to recognize such deficiencies at an early stage and take necessary measures. However, the conventional system is not configured to accurately recognize the above-mentioned deficiencies.

Even when an auto-tuning drive source is provided in the NMR probe, the indicated value to the drive source for realizing the rotational position of the internal shaft may deviate from the actual rotational position of the internal shaft. Such deficiencies need to be quickly recognized by the user.

  An object of the present invention is to improve the reliability of auto-tuning in an NMR measurement system capable of auto-tuning. Alternatively, the user can recognize a connection failure of the external operation member. Alternatively, an NMR measurement probe having high functionality is realized.

(1) An NMR measurement system according to the present invention includes an NMR detection circuit having a variable capacitor for adjustment, an internal shaft connected to the variable capacitor, and a drive for driving the internal shaft during auto-tuning. A driving unit that generates force, a rotation detector that detects the rotational position of the internal shaft as an actual measurement value, and a driving force transmission path between the driving unit and the internal shaft based on the actual measurement value. And determining means for determining abnormality.

  According to the above configuration, the capacity of a variable capacitor (for example, a tuning capacitor or a matching capacitor) in the NMR detection circuit is operated via the internal shaft during auto tuning. That is, the capacity of the variable capacitor is varied by driving the internal shaft. A driving force (rotational force) generated by the driving unit is transmitted to the internal shaft. Such a rotation position (rotation speed, rotation angle, etc.) of the internal shaft is actually detected as an actual measurement value by the rotation detector. The determination means determines an abnormality, that is, an error on the driving force transmission system path based on the actually measured value. Thus, according to the above configuration, since the rotational position of the internal shaft is actually detected, it is possible to quickly and reliably determine abnormality in driving force transmission based on the detection result. Preferably, when an abnormality is determined, this is notified to the user. In response to the abnormality determination, a measure for solving the abnormality may be automatically executed.

  In the above configuration, it is desirable that the driving unit is provided in the external unit. In that case, the drive unit and the internal shaft are connected by an external shaft as a drive force transmission member. In the configuration in which the external shaft is attached to and detached from the NMR measurement probe, shaft connection failure is particularly likely to occur. In this case, if the above configuration is adopted, the reliability of auto-tuning can be improved. It is also possible to arrange the drive unit in the NMR measurement probe. Even in such a case, according to the above configuration, an abnormality occurring on the driving force transmission path can be detected, so that it is possible to avoid the occurrence of poor auto-tuning.

  Although it is possible to connect the rotation detector directly to the rotating shaft of the variable capacitor, such a configuration requires the provision of a rotation detector in the head of the NMR measurement probe. There is a risk that the rotation will be difficult, or such a rotation detector may adversely affect the NMR measurement. Therefore, it is desirable to arrange the rotation detector in the base of the NMR measurement probe. As the rotation detector, a potentiometer, an optical detector or the like can be used. When a gear mechanism is provided between the outer shaft and the inner shaft, it is desirable to incorporate a rotation detector in the gear mechanism. According to such a configuration, a desired rotation ratio can be easily realized among the outer shaft, the inner shaft, and the rotation detector. In this configuration, rotation of the internal shaft is indirectly detected.

  Since the actual measurement value represents the actual rotational position of the internal shaft, various abnormality determinations can be made based on the actual measurement value. For example, it is possible to determine slip on driving force transmission, non-establishment or disconnection of driving force transmission path, etc. based on the presence / absence of the deviation of the measured value with respect to the instruction value (calculated value or control value) to the driving unit. Is possible. Further, in a configuration in which a plurality of external shafts are connected to a plurality of connection ports, it is possible to determine an erroneous connection. It is also possible to determine an abnormality from the actual measurement value itself or its change. For example, if the measured value does not change even when a driving force is applied, an error such as forgetting to connect or disconnecting the external shaft can be determined. The quality of the entire transmission path including the drive unit and the internal shaft may be determined based on the actual measurement value.

  The determination means is arranged inside or outside the NMR measurement probe. It is also possible to provide a determination unit in a system control unit that controls the entire system. When an abnormality is determined, it is desirable to provide means for notifying the NMR measurement probe of the abnormality in order to promptly notify the operator (user) in the vicinity of the NMR measurement probe of the fact. Examples of such means include a display, a light emitter, and a speaker. It is desirable to display an abnormal path (abnormal channel) and an abnormal type on the display screen in order to cope with the abnormality by the operator. A coping method (guidance) according to the abnormality type may be displayed.

  Preferably, the driving unit generates the driving force based on an instruction value for auto-tuning, and the determination unit determines the abnormality by comparing the instruction value with the actually measured value. According to this configuration, it is possible to determine the difference in the actually measured value with respect to the calculated value or the indicated value as the theoretical value, and therefore it is possible to determine an abnormality from the presence or absence and the degree of the difference. The amount of deviation during rotation in one direction may be compared with the amount of deviation during rotation in the other direction. It is also possible to use this as a correction value for control. The comparison result between the instruction value and the actual measurement value may be directly used for feedback control. Preferably, when the external shaft is connected to the internal shaft, the rotational position at that time is read as an initial value, and the indicated value is calculated based on the initial value. When a pulse motor is used as the drive unit, the instruction value corresponds to, for example, the number of pulses supplied to the pulse motor. A control value based on the number of pulses may be compared with an actual measurement value, or a value obtained by converting the pulse number into a rotational position may be compared with the actual measurement value.

  Preferably, the determination unit determines the abnormality when a difference between the instruction value and the actual measurement value exceeds an allowable range. The allowable range may be configured to be variably set automatically by the user or according to the situation. The permissible range may be switched between when rotating in one direction and when rotating in the other direction.

  Preferably, the NMR detection circuit, the internal shaft, and an NMR measurement probe having the rotation detector, the driving unit, and an external unit having an external shaft for transmitting the driving force, The NMR measurement probe further includes an external connection port that is a rotational member mechanically coupled to the internal shaft and to which the external shaft is detachably connected. The connection error of the external shaft to the external connection port is determined. In the configuration in which the external shaft is attached to and detached from the external connection port, an abnormality in driving force transmission is likely to occur particularly at the connection location. Can be recognized promptly and necessary measures can be taken, thereby improving the reliability of auto-tuning.

(2) Another NMR measurement system according to the present invention includes an NMR detection circuit having a plurality of variable capacitors for adjustment, a plurality of internal shafts connected to the plurality of variable capacitors, and a plurality of internal shafts during auto-tuning. A drive unit that generates a driving force for individually driving the internal shaft, a plurality of rotation detectors that detect a plurality of rotational positions of the plurality of internal shafts as a plurality of actual measurement values, and a plurality of the actual measurement values And determining means for individually determining abnormality in a plurality of driving force transmission paths between the driving unit and the plurality of internal shafts.

  According to the above configuration, the plurality of internal shafts for operating the plurality of variable capacitors in the NMR detection circuit are coupled, and the rotational positions of the plurality of internal shafts are a plurality of rotation detectors by the plurality of rotation detectors. It is individually detected as an actual measurement value. As a result, it is possible to determine a transmission abnormality with respect to individual paths constituting a plurality of driving force transmission paths. According to this configuration, since a path in which an abnormality has occurred can be identified, information for specifying the abnormal path can be provided to the user.

  Preferably, the driving unit generates a driving force for individually driving the plurality of internal shafts based on a plurality of instruction values for auto-tuning, and the determination means includes the plurality of instruction values. The abnormality is individually determined by comparison with the plurality of actually measured values. Preferably, the determination unit determines an abnormal route in which the abnormality has occurred and a type of the abnormality. Desirably, the said determination means determines an incorrect connection, a slip, and idle rotation as said abnormality classification. If there are multiple connection ports and they have the same specifications, there is a possibility of incorrect connection of the external shaft. That is, there is a possibility that another external shaft may be erroneously connected to a certain connection port instead of the corresponding external shaft. According to the above configuration, since it is possible to confirm the presence or absence of a change in the actual measurement value at the time of driving force transmission for each connection port, it is possible to easily identify an erroneous connection. When an erroneous connection is determined, this may be notified, or the control conditions may be changed so that the correspondence between the drive source and the internal shaft is correct.

(3) An NMR measurement probe according to the present invention is a portion that is inserted into a cavity portion of a magnetic field generator and includes an NMR detection circuit having a plurality of variable capacitors for adjustment, and is connected to the insertion portion A plurality of internal shafts for operating the plurality of variable capacitors across the insertion part and the base part, and a base part disposed outside the cavity part. A driving force is transmitted to the plurality of internal shafts from an internal drive source or an external drive source during auto tuning, and the base portion is configured to control the operations of the internal drive source or the external drive source during auto tuning. A plurality of rotation detectors for detecting a plurality of rotational positions of the internal shaft as a plurality of actual measurement values are provided.

  According to the above configuration, since a plurality of rotation detectors are provided in the NMR measurement probe, the rotational position of each internal shaft is individually detected as an actual measurement value, and abnormality determination and operation control are performed based on the detected value. Yes. Since each rotation detector is provided at the base of the NMR measurement probe, not at the insertion portion, the insertion portion can be reduced in size, and the plurality of rotation detectors can be separated from the transmission / reception coil and applied to the magnetic field by the plurality of rotation detectors. The impact can be reduced. The actually measured value is used when controlling the operation of the internal drive source or the external drive source during auto-tuning. For example, when an abnormality in driving force transmission is determined, control for stopping the operation of the internal driving source or the external driving source is executed. The internal drive source is a drive source provided in the NMR measurement probe, for example, in the base thereof, and the external drive source is a drive source provided outside the NMR measurement probe. Although it is desirable to provide a driving source for each individual internal shaft, it is also possible to share the driving source. Determination of abnormality in driving force transmission is performed in a circuit provided inside or outside the NMR measurement probe.

  Preferably, the base has a display for displaying an abnormality when an abnormality occurs in the transmission of the driving force. Examples of such a display device include a light emitting device in addition to a display device for displaying characters and the like. Since the base is generally exposed, if the display is provided there, the operator can easily visually recognize the display contents. In order to improve visibility, it is desirable to provide a display on the side surface (vertical surface) of the base. However, an abnormality may be displayed on the portable display or the like by wireless communication or the like.

According to the present invention, the reliability of auto-tuning can be improved in an NMR measurement system capable of auto-tuning. Alternatively, the user can recognize the connection failure of the external operation member. Alternatively, an NMR measurement probe having high functionality can be provided.

1 is a block diagram showing a preferred embodiment of an NMR measurement system according to the present invention. It is a block diagram which shows the structure regarding an auto tuning especially in the NMR measuring system shown in FIG. It is a perspective view which shows the base part of a NMR probe. It is a figure which shows the example of a display of the indicator provided in the NMR probe. It is a figure which shows the internal structural example of the base part of a NMR probe. It is a figure which shows the structural example of a gear part. It is a flowchart which shows the operation example in auto tuning. It is a flowchart which shows the operation example in the process of S26 and S34 shown in FIG. It is a flowchart which shows the operation example in the process of S18 shown in FIG.

  FIG. 1 is a block diagram showing a preferred embodiment of the NMR measurement system according to the present invention. This NMR measurement system is a system for measuring an NMR (nuclear magnetic resonance) signal generated by an observation nucleus in a sample.

  In FIG. 1, the NMR measurement system 10 includes a spectrometer 12, a relay device 14, an NMR probe 16, a system control unit 19 and the like in this embodiment. In the present embodiment, the NMR measurement system 10 further includes an auto tuning unit 18.

  The spectrometer 12 constitutes a console. Specifically, the spectrometer 12 has a transmission unit 20 and a reception unit 22. The transmission unit 20 generates a transmission signal in the tuning mode and the NMR measurement mode, and outputs the transmission signal to the NMR detection unit 32 in the NMR probe via the relay device 14. The transmission unit 20 includes a signal generator, a power amplifier, and the like. The reception unit 22 is a circuit that receives a reception signal (NMR detection signal) output from the NMR detection unit 32 via the relay device 14 and performs predetermined processing on the reception signal. The signal processed by the receiving unit 22 is passed to an FFT circuit (not shown). Thereby, a spectrum is generated based on the reception information. In the present embodiment, manual tuning and auto-tuning can be selected when the NMR detector 32 is adjusted, that is, tuned. In the latter auto tuning, an auto tuning unit 18 is used.

  In this embodiment, the relay device 14 is configured as a head amplifier chassis. The relay device 14 receives a reception signal from the NMR probe 16 and a function of relaying a transmission signal from the transmission unit 20 to the NMR probe 16. A function of relaying to the unit 22. The relay device 14 has a directional coupler (transmission / reception separating circuit) (not shown), and a transmission signal from the transmission unit 20 is output to the NMR probe 16 via the directional coupler. A reception signal from the NMR probe 16 is extracted by the directional coupler, and the extracted reception signal is output to the reception unit 22. The directional coupler includes a preamplifier that amplifies the received signal in the present embodiment. The relay device 14 includes a circuit that detects a level (return loss level) of a reflected wave reflected and returned by the NMR probe 16 and a display that displays the circuit. In the present embodiment, the relay device 14 is connected to an auto tuning unit 18 as an external unit for the NMR probe 16. This will be described in detail later.

  The NMR probe 16 is roughly composed of an insertion portion 24 and a base portion 26. The magnetic field generation device 28 is a device that generates a static magnetic field, and an insertion portion 26 is inserted into a bore 28A as a hollow portion that extends in the vertical direction and is formed in the center portion thereof. An NMR detector 32 is provided in the probe head 30 in the insertion portion 24. The NMR detector 32 includes electronic components such as a transmission / reception coil, a tuning capacitor, and a matching capacitor for detecting NMR signals.

  In this embodiment, as shown later using FIG. 2, two transmission / reception coils (a high-frequency transmission / reception coil and a low-frequency transmission / reception coil) are provided. Is provided.

  As shown in FIG. 1, a plurality of internal shafts 38 are provided so as to extend across the insertion portion 24 and the base portion 26, that is, straddle them. In the present embodiment, for example, five internal shafts are arranged. However, only one of them is shown in FIG. The tip of each internal shaft 38 for variable capacity is connected to the rotating shaft of each variable capacitor. By rotating each internal shaft 38, it is possible to vary the capacity of each variable capacitor. In this embodiment, as will be described later, it is possible to variably set the capacities of four variable capacitors using four internal shafts. Five bands are set for the low frequency band, and a tuning capacitor and a matching capacitor are provided for each band. One internal shaft is arranged for band switching.

  The base 26 is a portion exposed below the bore 28A of the magnetic field generator 28, and a plurality of mechanical units 40 and electronic units 46 are provided therein. In the present embodiment, each mechanical unit 40 includes a gear unit and a potentiometer that forms a rotation detector. Reference numeral 42 denotes a connection port to the internal shaft 38, and the tip of an external shaft (flexible shaft) can be detachably connected to the connection port 42. The external shaft 44 is a driving force transmission member, and the internal shaft 38 can be rotated outside through the external shaft 44. The rotation ratio in that case is determined by the gear portion in the mechanical unit 40. In the present embodiment, as described above, five internal shafts are provided, and at the time of auto-tuning, five external shafts are connected to the five connection ports that they have. Each of the five connection ports functions as a knob during manual tuning. That is, in manual tuning, the five connection ports as knobs are rotated by the user.

As will be described in detail later, the electronic unit 46 includes a microcomputer, a display, a memory, an A / D converter, and the like. Output signals output from a plurality of potentiometers are given to the electronic unit 46. Based on these signals, the electronic unit 46 can recognize the rotational positions of the five internal shafts as measured values. Reference numeral 34 denotes a port to which a transmission / reception cable is connected, and a signal line 36 is disposed between the port 34 and the NMR detector 32. In the present embodiment, actually, two transmission / reception coils are provided, and two ports corresponding to them are provided. This will be described later with reference to FIG.

  The auto tuning unit 18 has a microcomputer, a plurality of motors, and the like. The auto tuning unit 18 also controls the electronic unit 46 in the NMR probe 16. The auto tuning unit 18 acquires necessary information from the electronic unit 46 and performs auto tuning control based on the information. As described above, in this embodiment, five external shafts are provided, and a motor is connected to the tail end, that is, the rear end of each external shaft. The operation of each motor is controlled by a microcomputer in the auto tuning unit 18. Specifically, a pulse signal having the number of pulses corresponding to the indicated value is given to each motor, thereby defining the rotational position of the external shaft.

Electric power is supplied from the auto-tuning unit 18 to the electronic unit 46. However, a unique power source may be provided in the NMR probe 16. In the NMR measurement mode (actual measurement mode), a transmission signal having high power is generated, while in the tuning mode, a transmission signal having weak power is generated.

  FIG. 2 shows a configuration related to auto tuning among the system configurations shown in FIG. More specifically, FIG. 2 shows details of the relay device 14 and the NMR probe 16.

In FIG. 2, a first system for performing high-frequency transmission is indicated by reference numeral 48, and a second system for performing low-frequency transmission is indicated by reference numeral 50. Corresponding to these two systems, two detection circuits 106 and 108 are provided in the relay device 14. Each of the detection circuits 106 and 108 is a circuit for extracting a reflected wave component, and detection signals from the detection circuits 106 and 108 are input to the conversion circuit 110. The conversion circuit 110 is a circuit that generates a level signal representing a return loss level from the detection signal, and the conversion circuit 110 includes an A / D converter in the present embodiment. Since the high-frequency transmission and the low-frequency transmission are executed at least in the tuning process at the same time, the conversion circuit 110 is shared between these transmissions. In the present embodiment, the level signal 111 is output to the display processing circuit 112 and the microcomputer 118 in the auto tuning unit 18.

  The display processing circuit 112 performs a predetermined display process on the level signal, thereby generating a display signal for displaying the reflected wave level on the display 114. In this case, the reflected wave display gain can be switched and set by the user as indicated by reference numeral 116. The display 114 is configured by a liquid crystal display, for example, and the reflected wave level is displayed in a form such as a multi-segment display (bar graph). When manual tuning is performed, the capacitances of the tuning capacitor and the matching capacitor are manually optimized so that the reflected wave level is minimized while observing the display content. Incidentally, in the present embodiment, the reflected wave level is also displayed on the display 102 of the NMR probe 16, and in manual tuning, each capacitor is based on the reflected wave level displayed on the display 102. It is possible to set the capacity. Also in the auto tuning, the reflected wave level can be confirmed by the display content of the display 102.

  The auto tuning unit 18 is a unit that is externally added to the relay device 14 in the present embodiment. An auto tuning unit may be incorporated in the relay device 14. Alternatively, various functions of the auto tuning unit 18 may be incorporated in the NMR probe 16.

As already described, the auto-tuning unit 18 is for performing automatic adjustment in the auto-tuning mode. In the present embodiment, a microcomputer 118 composed of a CPU and an operation program is provided. In the present embodiment, five motors 120, 122, 124, 126 are provided in the auto tuning unit 18, and five external shafts 84, 86, 88, 90, 92 are driven by them. Yes. In FIG. 2, four motors 120, 122, 124, 126 and four external shafts 84, 86, 88, 90 for operating the capacitor capacity are shown. The band switching motor and the external shaft are not shown. In the present embodiment, the motors 120, 122, 124, 126 are constituted by pulse motors, and pulse signals from the microcomputer 118 are output to the motors 120, 122, 124, 126 via an interface (not shown). ing. In generating each pulse signal, the microcomputer 118 generates a pulse signal having the number of pulses corresponding to the indicated value indicating the rotational position (dial value) obtained in the calculation. The microcomputer 118 is controlled by the system control unit shown in FIG. 1, and a control signal for this purpose is indicated by reference numeral 127.

  In the present embodiment, the microcomputer 118 has a function of transmitting the input level signal 111 or information indicating the level signal 111 to the NMR probe 16. Further, the microcomputer 118 has a function of comparing the instruction value and the actual value for each internal shaft, thereby determining an abnormality in transmission of the driving force. Further, the microcomputer 118 also executes control for forcibly stopping the motor corresponding to the capacitor when the indicated value or the actually measured value reaches the upper limit value and the lower limit value determined for each capacitor.

Note that the microcomputer 118 may have a function of the display processing circuit 112. The reflected wave level signal 111 may be transmitted to the NMR probe 16 without going through the microcomputer 118. In the present embodiment, the control signal 127 from the system control unit is sent to the microcomputer 94 via the microcomputer 118, but the control signal may be directly given to the microcomputer 94 from the system control unit. In FIG. 2, a communication line between the microcomputer 118 and the microcomputer 94 is indicated by reference numeral 130. The operation contents of the microcomputer 118 and the like will be described in detail later with reference to FIGS.

  As described above, the NMR probe 16 has the insertion portion 24 and the base portion 26. The insertion unit 24 includes an NMR detection unit 32. In the present embodiment, the NMR detector 32 has two detection circuits, a high-frequency detection circuit and a low-frequency detection circuit. The high-frequency detection circuit has a tuning capacitor 52 and a matching capacitor 54 in addition to a transmission / reception coil. Regarding low-frequency transmission, in this embodiment, five bands are defined, and a tuning capacitor 56 and a matching capacitor 58 are provided for each band. A capacitor pair is selected by selecting a band. Each capacitor is a variable capacitor whose capacity can be varied. In this embodiment, a multi-rotation type capacitor is used. In summary, in this embodiment, the NMR detector 32 has a high frequency capacitor pair and five low frequency capacitor pairs. The high frequency capacitor pair is composed of a tuning capacitor 52 and a matching capacitor 54, and the low frequency capacitor pair in each band is composed of a tuning capacitor 56 and a matching capacitor 58.

  In this embodiment, five internal shafts are provided across the insertion portion 24 and the base portion 26. In FIG. 2, four internal shafts 60, 62, 64, 66 are shown therein. An internal shaft not shown is for band switching. Each of the internal shafts 60, 62, 64, and 66 transmits the rotational force to the corresponding capacitor, thereby changing the capacity of the corresponding capacitor.

A plurality of mechanical units 40 are provided in the base portion 26 as described above. In this embodiment, five machine units 40 are provided, and each machine unit 40 has a gear part and a potentiometer. In FIG. 2, four gear portions 68, 70, 72, and 74 among the five gear portions are illustrated. Of the four potentiometers, four potentiometers 92 are shown. In FIG. 2, only one potentiometer 92 is shown as a representative of them.

  Five shaft members are provided so as to penetrate the lower surface plate 83 in the base portion 26, and connection ports are provided in the respective shaft members. In FIG. 2, four shaft members are illustrated among the five shaft members, and four connection ports 76, 78, 80, and 82 are illustrated among the five connection ports. Corresponding external shafts 84, 86, 88, 90 are detachably connected to the connection ports 76, 78, 80, 82. Therefore, when any one of the external shafts is rotated, the rotational force is transmitted to the specific internal shaft through the specific shaft member and the specific gear portion, and the rotary shaft is rotated. The rotational movement causes the condenser shaft to rotate, thereby changing the capacity. In that case, the rotational position of the internal shaft is detected by the potentiometer 92, and the detection signal 98 is sent to the microcomputer 94.

  Each gear part 68, 70, 72, 74 is for realizing a desired rotation ratio. More specifically, in each gear portion 68, 70, 72, 74, the rotational speed j of the internal shaft relative to the rotational speed i of the connection port (external shaft) is defined, and the rotation of the connection port (external shaft) A potentiometer rotation number k for the number i is defined. The ratio of i to j to k can be arbitrarily set depending on the configuration of the gear unit. The gear ratio is determined from the viewpoint of the rotational speed of the capacitor, the rotational speed of the potentiometer, adjustment accuracy, and the like. A configuration example of the gear unit will be described later with reference to FIG.

  Next, the electronic unit 46 provided in the base 26 will be described. In the base portion 26, a microcomputer 94 composed of a CPU and an operation program is provided. An A / D converter 96 is connected to the microcomputer 94, and a memory 100 and a display 102 are connected. The A / D conversion unit 96 is a module that converts detection signals from the five potentiometers 92 from analog signals to digital signals. Those detection signals are recognized by the microcomputer 94. Therefore, the microcomputer 94 can monitor the rotational position of each internal shaft as an actual measurement value in real time. The memory 100 is constituted by, for example, a non-volatile memory, and a plurality of unique parameters necessary for auto tuning are stored on the memory 100. For example, information such as dial values corresponding to the upper limit and lower limit of each variable capacitor, the reduction gear ratio in each gear unit, and the motor rotation speed in auto tuning are stored as such inherent parameters. For each variable capacitor, the rotation limit value stored in the memory 100 and the actual measurement value (including the converted value) are compared as needed, and when the actual measurement value reaches the limit, the rotational drive of the shaft is forcibly stopped. It is desirable to configure so that In that case, a determination value for comparison may be set immediately before the limit value. Such stop control is executed by the microcomputer 94 or the microcomputer 118. According to this configuration, the variable capacitor can be protected.

  The display unit 102 is configured by a liquid crystal display unit in the present embodiment, the reflected wave level is displayed in a graph on the display screen of the display unit 102, and a dial value, that is, a capacitance setting value for each capacitor is a numerical value. Is displayed. The dial value corresponds to the actually measured value in this embodiment. When an abnormality is determined on any of the rotational force transmission paths, it is desirable to display that fact and the abnormal path on the display 102. In addition, it is desirable that the abnormality type, the degree of abnormality, and the like are displayed on the display 102. Such an abnormality may be displayed by lighting of a light emitting element such as an LED. Normal display may be performed instead of the abnormal display.

  Reference numeral 104 denotes a DIP switch, and a probe ID code is registered by the switch 104. The microcomputer 94 reads the value of the switch 104 as necessary and outputs the information to the outside. The probe ID code may be read out without going through the microcomputer 94.

  In the present embodiment, control such as abnormality determination is executed in the microcomputer 118 on the auto tuning unit 18 side, but the function may be realized in the microcomputer 94. For example, when a drive source for driving each internal shaft is arranged in the base portion 26, that is, when auto-tuning is performed without using an external shaft, auto-tuning control and abnormality determination are performed in the microcomputer 94 in the base portion 26. desirable. In this embodiment, when an abnormality is determined, the information is notified to the user, and the driving of the motor on the path where the abnormality has occurred is forcibly stopped. In addition to notifying the abnormality, a message indicating a coping method for eliminating the abnormality may be displayed on the display 102 or the like.

  Next, the configuration of the base in the NMR probe will be described with reference to FIGS. In FIG. 3, the base 26 of the NMR probe 16 is schematically shown as a perspective view. The base 26 has a box-shaped case, and a display 132 is provided on a specific side surface 26A of the case. In this embodiment, five connection ports 76, 78, 80, 82, 84 are provided on the bottom surface 26 </ b> B of the base portion 26, and the external shafts 85, 86 are respectively connected to the connection ports 76, 78, 80, 82, 84. The tip of is connected. In the figure, only two external shafts 85, 86 are shown. Incidentally, it is possible to perform manual tuning by pinching and rotating the connection ports 76, 78, 80, 82, 84 by hand. In a state where the outer shaft is completely connected to the connection port, the rotational force sent through the outer shaft is reliably transmitted to the inner shaft.

  FIG. 4 shows a display example of the display screen 132A of the display device. The display screen 132A includes a level indicator 134 as a level meter. This is composed of a plurality of segments, and represents the level of the reflected wave by the number of segments. The display screen 132A further includes four dial value displays 136, 138, 140, and 142 in this embodiment. Here, these dial values correspond to actual measured values. Dial value displays 136 and 138 indicate the dial values of the tuning and matching capacitors for low frequencies. The dial value displays 140 and 142 indicate the dial values of the tuning and matching capacitors corresponding to the selected low frequency band. In the present embodiment, each dial value varies in the range of 0-7500. Of course, those numbers are merely examples. Incidentally, it is desirable to configure the NMR probe so that the display gain of the reflected wave level can be variably set by the user.

  FIG. 5 shows a state in which the base portion 26 of the NMR probe 16 is viewed from below. FIG. 5 shows an example of the internal structure of the base 26. In the base portion 26, five gear portions 68, 70, 72, 74, and 76 are provided in a ring-like arrangement. A display 132 is provided on the base 26, and a display processing substrate is provided on the back side thereof. Further, a control board 144 is provided in the base portion 26, and the above-described microcomputer or the like is mounted on the control board 144.

  FIG. 6 shows a configuration example of the gear portion 68 as a representative of the five gear portions. The gear portion 68 is composed of a plurality of gears, and includes a planetary gear and the like. The gear portion 68 is provided between the connection port 76 and the internal shaft 60. An external shaft 84 is detachably connected to the connection port 76. A gear connected to the shaft of the potentiometer 92 meshes with a gear provided at the proximal end portion of the internal shaft 60. The potentiometer 92 directly detects the rotational position of the internal shaft 60, and indirectly detects the rotational position or capacitance of the variable capacitor. In the present embodiment, the rotational position of the internal shaft 60 is detected as the voltage of the output signal of the potentiometer 92. Instead of the potentiometer 92, another rotation detector can be provided. For example, a rotary encoder or the like may be provided. As shown in FIG. 6, the center axis of the connection port of the outer shaft 84 and the center axis of the inner shaft 60 are shifted. Specifically, it is shifted in the radial direction in the annular arrangement of the plurality of gear portions in the internal structure shown in FIG. Thereby, the space between the five connection ports can be widened to secure the installation space for each member.

  Next, an example of operation in auto-tuning and abnormality determination will be described with reference to FIGS.

FIG. 7 shows a flowchart of an operation example of the auto tuning unit 18 and the NMR probe 16. Each step shown in FIG. 7 particularly shows the control operation of the microcomputer 118 and the microcomputer 94 shown in FIG.

In S10, a plurality of external shafts of the auto tuning unit 18 are connected to the NMR probe 16 by an operator, that is, a user, and the auto tuning unit 18 and the NMR probe 16 are electrically connected. . In S12, auto-tuning is started by a predetermined operation by the user. In S <b> 14, information is transmitted from the NMR probe 16 to the auto tuning unit 18 based on a request from the auto tuning unit 18. The information includes a current value of each capacitor, that is, an actual measurement value, a dial value indicating an upper limit and a lower limit of each capacitor, a reduction gear ratio in each gear unit, a rotation speed of each motor, and the like. In S16, initial setting is performed in the auto tuning unit 18. Specifically, the acquired current value (actual value) is recognized and set as an initial value. The instruction value is generated based on such an initial value. In S18, a connection test is executed as necessary. This corresponds to self-diagnosis, and the specific contents will be described later with reference to FIG.

In S20, automatic adjustment for the first detection circuit in the NMR signal detection unit is executed. In this case, the adjustment is performed according to the conventional automatic tuning algorithm. In the adjustment process, as shown in S22 and S24, reflected wave level information is sent from the auto tuning unit 18 to the NMR probe 16, and the reflected wave level is displayed on the NMR probe 16. Such transmission is repeated intermittently. In S26, the presence or absence of a transmission error, that is, an abnormality is monitored for each driving force transmission line. This will be described in detail later with reference to FIG. 8. In S26, basically, the instruction value and the actual measurement value are compared for each driving force transmission path, and the difference between them exceeds a predetermined allowable range. An abnormality is determined. If an abnormality is determined, this is notified to the user, and the operation of the motor in the rotational force transmission system is forcibly stopped. In notifying the user, in addition to the presence / absence of an abnormality, information such as an abnormality type, a place where the abnormality has occurred, and the degree of abnormality may be provided together.

  When the process of S20 ends, automatic adjustment of the second detection circuit included in the NMR detector is executed in S28. The automatic adjustment of the second detection circuit is basically the same as the automatic adjustment of the first detection circuit. That is, S28 includes steps S30 and S32, and further includes S34 for monitoring a transmission error. When the automatic adjustment for the two detection circuits is completed, the end of auto-tuning is determined in S36. In S38, the microcomputer shifts to the standby mode, that is, the standby mode in the NMR probe 16. In S40, the NMR measurement is actually executed.

  FIG. 8 shows an operation example of the transmission error monitoring steps S26 and S34 shown in FIG. In S100, 1 is substituted into the parameter K. In S102, the Kth instruction value is compared with the Kth actually measured value. In S104, it is determined whether or not the difference is within an allowable range. If the difference is within the allowable range, S108 is executed, and if the difference is outside the allowable range, S106 is executed. In S106, an error is determined and displayed on the display. In that case, it is desirable to display information for identifying the path where the error has occurred. In the operation example shown in FIG. 8, S108 is executed after the process of S106, but of course, the operation may be temporarily stopped when S106 is executed.

  In S108, it is determined whether or not the parameter K has reached the maximum value. If it has not reached, K is incremented by one in S110, and each step after S102 is repeatedly executed. In S112, it is determined whether or not to continue the present process as it is, and in the case of continuing, each process after S100 is repeatedly executed.

  As described above, in the process of performing auto-tuning, that is, in the situation where the capacitance of each capacitor is variably set, the indicated value calculated for each capacitor and the actually measured value are Are compared, and if the difference between the two becomes larger than a predetermined value, an error is determined. Thereby, for example, it is possible for the user to recognize the disconnection or incomplete connection of the external shaft. Indirectly, it is also possible to recognize a motor abnormality, a gear section malfunction, a potentiometer malfunction, and the like. Therefore, according to the above configuration, it is possible to avoid the problem that auto-tuning is executed without knowing such a problem and the auto-tuning result becomes poor, thereby improving the reliability of auto-tuning. It is possible to increase. In addition, when an abnormality is detected, it is possible to cope with it promptly.

  FIG. 9 shows a specific operation example of the connection test S18 shown in FIG. In S200, 1 is substituted for the parameter K. In S202, all actually measured values are monitored while the Kth instruction value is varied on a trial basis. In S204, it is determined whether or not the Kth actual measurement value has changed. If it is determined in S204 that there is no change in any of the actual measurement values, it is determined in S206 that the idle rotation has occurred. That is, it is determined whether the external shaft is not connected or the external shaft is disconnected. On the other hand, if it is determined in S204 that an actual measurement value other than the Kth actual measurement value has changed, an incorrect connection is determined in S208. That is, it can be recognized that another external shaft is connected to a certain connection port instead of a regular external shaft.

If it is determined in S204 that the Kth actual value has changed, it is subsequently determined in S210 whether or not the difference between the Kth instruction value and the Kth actual value has changed. If it has changed, a slip is determined in S212. That is, it is determined that the output rotation amount is deviated from the input rotation amount due to, for example, a gear portion failure. In S214, it is determined whether or not K has reached the maximum value. If it has not reached, K is incremented by one in S216, and each step after S202 is repeatedly executed. Finally, in S218, the self-diagnosis result including the determination result as described above is displayed on the screen. In this case, it is desirable that the diagnostic result is displayed on the display of the main console together with the display of the NMR probe. Such a diagnosis result includes the type of abnormality in addition to the presence / absence of abnormality, and also includes information for specifying the abnormal part.

Using the above function, the difference between the indicated value when the internal shaft is rotated in one direction and the actually measured value, and the difference between the indicated value and the actually measured value when the internal shaft is rotated in the other direction And the degree of backlash generated in the gear portion may be evaluated.

According to the configuration according to the present embodiment described above, a potentiometer is provided for each internal shaft in the NMR probe so that the rotational position of the internal shaft is detected as an actual measurement value. Therefore, transmission is performed based on the actual measurement value. Various controls such as determination of abnormality can be performed. Therefore, reliability in auto-tuning can be improved, and when any abnormality occurs, it is possible to quickly cope with the abnormality. In the present embodiment, in addition to the presence / absence of an abnormality, the location where the abnormality has occurred can be specified, and the type of abnormality can be identified. In the above embodiment, the auto tuning unit is provided outside the NMR probe. However, an auto tuning function may be provided in the NMR probe. However, when an external auto-tuning unit is provided and a plurality of flexible shafts are detachably connected to the NMR probe, inherent problems such as poor connection and shaft detachment are likely to occur. In this case, it is desirable to provide the above abnormality determination function.

  10 NMR measurement system, 12 spectrometer, 14 relay device, 16 NMR probe, 18 auto tuning unit, 32 NMR detector, 52, 54, 56, 58 variable capacitor, 60, 62, 64, 66 internal shaft, 68, 70 , 72, 74 Gear portion, 76, 78, 80, 82 Connection port, 84, 86, 88, 90 External shaft, 120, 122, 124, 126 Motor.

Claims (12)

In an NMR measurement system comprising an NMR measurement probe comprising an insertion portion inserted into a cavity of a magnetic field generator and a base connected to the insertion portion and disposed outside the cavity,
NMR detection circuit provided in the insertion portion and having a variable capacitor for adjustment;
An internal shaft provided across the insert and the base and connected to the variable capacitor;
A driving unit that is provided outside the NMR measurement probe and generates a driving force for driving the internal shaft during auto-tuning;
An external shaft for transmitting the driving force;
An external connection port provided at the base and mechanically coupled to the internal shaft, to which the external shaft is detachably connected;
A rotation detector provided at the base for detecting the rotational position of the internal shaft as an actual measurement value;
Determination means for determining an abnormality that has occurred on a driving force transmission path between the drive unit and the internal shaft based on the measured value;
Informing means provided in the base and informing the abnormality when the abnormality is determined;
An NMR measurement system comprising: The system of claim 1, wherein
The driving unit generates the driving force based on an instruction value for auto tuning,
The determination means determines the abnormality by comparing the indicated value with the actual measurement value;
An NMR measurement system characterized by that. The system of claim 2, wherein
The determination means determines the abnormality when a difference between the indicated value and the actually measured value exceeds an allowable range.
An NMR measurement system characterized by that. The system according to any one of claims 1 to 3 ,
Before Symbol judging means as the abnormality, it determines connection error of said outer shaft to said external connection port,
An NMR measurement system characterized by that. The system of claim 1 , wherein
The notification means has a display for displaying the abnormality.
An NMR measurement system characterized by that. In an NMR measurement system comprising an NMR measurement probe comprising an insertion portion inserted into a cavity of a magnetic field generator and a base connected to the insertion portion and disposed outside the cavity,
NMR detection circuit provided in the insertion portion and having a plurality of variable capacitors for adjustment;
A plurality of internal shafts provided across the insertion portion and the base and connected to the plurality of variable capacitors;
A drive unit that is provided outside the NMR measurement probe and generates a driving force for individually driving a plurality of internal shafts during auto-tuning;
A plurality of rotation detectors provided at the base for detecting a plurality of rotational positions of the plurality of internal shafts as a plurality of actually measured values;
A determination unit for individually determining an abnormality for a plurality of driving force transmission paths between the driving unit and the plurality of internal shafts based on the plurality of actually measured values;
Informing means provided in the base and informing the abnormality when the abnormality is determined;
An NMR measurement system comprising: The system of claim 6, wherein
The driving unit generates a driving force for individually driving the plurality of internal shafts based on a plurality of instruction values for auto-tuning,
The determination means individually determines the abnormality by comparing the plurality of instruction values with the plurality of actually measured values.
An NMR measurement system characterized by that. The system of claim 6, wherein
The determination means determines an abnormal route in which the abnormality has occurred and a type of the abnormality;
An NMR measurement system characterized by that. The NMR measurement system according to claim 8,
The determination means determines an erroneous connection, slip, and idle rotation as the type of abnormality.
An NMR measurement system characterized by that. The system of claim 1, wherein
Control means for stopping the operation of the drive unit when the measured value reaches a value based on a mechanical limit of the variable capacitor;
An NMR measurement system characterized by that. A part inserted into the cavity of the magnetic field generator and having an NMR detection circuit having a plurality of variable capacitors for adjustment, and a part connected to the insert and disposed outside the cavity And a base
A plurality of internal shafts for operating the plurality of variable capacitors across the insertion portion and the base portion are provided,
The plurality of inner shaft driving force from the external drive source during the auto-tuning is transmitted,
It said base a plurality of rotation detectors for detecting a plurality of rotational positions of said plurality of inner shaft as a plurality of measured values is provided, et al is to control the operation of front Kigai portion drive source during the auto-tuning in,
The base is provided with notifying means for notifying abnormality when a plurality of driving force transmission paths between the external driving source and the plurality of internal shafts are determined based on the plurality of actually measured values. Was,
An NMR measurement probe characterized by that. The probe according to claim 11, wherein
The notification means has a display for pre-displaying the Kikoto normal,
An NMR measurement probe characterized by that.

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