JP2005055396A - Power source frequency determination device, temperature regulator including the same, and analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine a commercial power source frequency in a district area by simple constitution, and to precisely regulate a temperature, in an analyzer provided with a heater for controlling supplied electric power by phase control of commercial alternating current power to regulate the temperature. <P>SOLUTION: A pulse signal is generated in response to the zero cross of a commercial alternating current voltage waveform by a zero-cross detecting circuit 10, a prescribed width of reset pulse is generated after 8.7ms counted from an edge of a zero-cross detecting signal, using a pulse signal generation function incorporated in a PWM control signal generation part 11 used for the phase control. In a flip-flop circuit 12, "H" is read in synchronized with the edge of the zero-cross detecting signal, and an output is "L" all the time because the "L" of a reset input terminal RST has priority when the power source frequency is 50 Hz. The output of the flip-flop circuit 12 is "H" all the time, because a signal level of an output terminal PWM2 is not brought into the "L" in 60 Hz. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power source frequency discriminating device for a commercial AC power source, a temperature control device including the device, and an analyzer having such a temperature control device.

  In many analyzers such as mass spectrometers, one or more temperature control units are installed in order to maintain a constant temperature, which is one of analysis conditions, or to perform an analysis according to a predetermined temperature profile. I have. For example, as disclosed in Patent Document 1, in the time-of-flight mass spectrometer, if the length of the ion flight space varies with temperature, this is reflected in the mass number error. Therefore, in order to ensure high analysis accuracy, the entire vacuum chamber containing the flight space is accommodated in a thermostatic chamber for temperature control. In such a mass spectrometer, fluctuations in the acceleration voltage applied to the ion accelerator that affects the velocity of ions introduced into the flight space are also reflected in the mass number error. Therefore, in order to reduce the influence of the ambient temperature on the voltage generation circuit that generates the acceleration voltage, the voltage generation circuit itself is also temperature-controlled.

  In general, in such a temperature control unit in an analyzer, in order to increase temperature accuracy or achieve rapid temperature increase, the heater is AC driven by a commercial AC power source and its power control is performed by phase control. There are many. For example, in phase delay control, which is one of the phase control methods, when a phase is delayed by a predetermined control angle from the time when a commercial AC voltage waveform zero-crosses, a semiconductor power switch for flowing an AC current to the heater is opened, Next, when the zero cross occurs, the semiconductor power switch is closed. And the electric power supplied to a heater is controlled by setting a control angle suitably.

  By the way, in Japan, two types of commercial AC power supply frequencies, 50 Hz and 60 Hz, are used depending on the region, and in the case of the above phase control method, if control is performed using the same control parameter, the commercial AC power supply frequency Depends on the power supply. If the accuracy of temperature control may be low, the difference in commercial AC power supply frequency can be ignored. However, for example, when high accuracy is required for temperature control as described above, the control parameter depends on the commercial AC power supply frequency. Need to be changed. For this reason, conventionally, a setting switch for the commercial AC power supply frequency is provided, and the setting is manually changed according to the frequency of the area where the analyzer is installed, for example, during installation of the device.

  Usually, in such an analyzer, after being delivered to the user from the device manufacturer, the installation location is not always frequently moved across regions having different commercial AC power supply frequencies. However, when such movement is performed, the setting change as described above tends to be forgotten, and for this reason, analysis performed after the movement of the apparatus may be wasted.

  On the other hand, devices for automatically discriminating the power supply frequency in household electric appliances that cause problems when the power supply frequency differs are conventionally known (see, for example, Patent Document 2). However, when such a conventional power frequency discriminating device is to be mounted, there is a problem that the number of parts increases and the cost increases.

JP2003-151488 (paragraph 0005 etc.) Japanese Patent No. 2516909

  The present invention has been made in view of such a problem, and the main object thereof is an area used in an analyzer having a temperature control device that controls temperature by controlling AC power by a phase control method. It is an object of the present invention to provide an analyzer that can perform high-precision temperature adjustment suitable for the frequency of a commercial AC power supply to be used without worrying about the above or performing any switching operation. Another object of the present invention is to provide a power supply frequency discriminating apparatus capable of discriminating a power supply frequency with a simple configuration, that is, at a low cost.

A power frequency discriminating apparatus according to the present invention, which has been made to solve the above problems,
a) zero-cross detection means for detecting a zero-cross point of a commercial AC voltage waveform and generating a first pulse signal;
b) The output level is inverted after the time corresponding to the zero cross generation time interval when the commercial AC power supply frequency is 60 Hz with reference to the appearance position of the edge of the first pulse signal, and the commercial AC power supply frequency Pulse signal generating means for generating a second pulse signal whose output level is inverted again after the edge generation timing of the next first pulse signal when the frequency is 50 Hz;
c) A flip-flop that reads the “H” level or the “L” level as data using the edge of the first pulse signal as a clock signal, and resets or sets the internal state by the second pulse signal in preference to the clock signal. Means,
It is characterized by having.

Moreover, the analyzer according to the present invention made to solve the above problems is an analyzer having a temperature control device that performs temperature control by controlling AC power by phase control with respect to commercial AC power.
a) a power frequency discriminating means for judging whether the frequency of the commercial AC power is 50 Hz or 60 Hz;
b) parameter setting means for changing the control parameter of the phase control according to the determination result of the power supply frequency;
It is characterized by having.

Embodiments and effects of the invention

  In the power source frequency discriminating apparatus according to the present invention, when the commercial AC power source frequency is 60 Hz, the pulse signal generating unit counts the basic clock signal with reference to the appearance position of the edge of the first pulse signal, for example, but the output is inverted. Since the edge of the next first pulse signal is input before, the output is not inverted. That is, the second pulse signal is not substantially generated. Therefore, the flip-flop means reads either “H” level or “L” level every time using the edge of the first pulse signal as a clock signal, and as a result, the output of the flip-flop means is “H” level or “ Fixed to one of the “L” levels.

  On the other hand, when the commercial AC power supply frequency is 50 Hz, the second pulse signal is also generated every time the first pulse signal is generated by zero crossing. In the flip-flop means, both the first pulse signal and the second pulse signal are input, but since the second pulse signal has priority, it is substantially the same as the first pulse signal is not input. The internal state of the means continues to be reset or set. As a result, the output of the flip-flop means is fixed at either the “L” level or the “H” level opposite to the case where the commercial AC power supply frequency is 60 Hz, and the power supply frequency discrimination result is obtained as the output of the flip-flop means. Will be.

  As a specific embodiment of the power source frequency discriminating apparatus according to the present invention, in the temperature control apparatus that includes the apparatus and performs temperature control by controlling AC power by phase control with respect to commercial AC power, the zero cross detection means Detects a zero cross point of a commercial AC voltage waveform for the phase control, and the pulse signal generation means generates a pulse signal corresponding to a control angle with reference to the appearance position of the edge of the first pulse signal. For example, the function of the PWM control circuit can be used, and parameter setting means for changing the control parameter for the phase control according to the output level of the flip-flop means can be provided.

  According to this configuration, since the circuit originally provided for performing the phase control as the zero-cross detection unit and the pulse signal generation unit can be used, only the flip-flop unit is substantially added as hardware. Good. Therefore, the configuration is very simple, and it is possible to mount an automatic power frequency switching function without adding a large cost.

  Further, in the analyzer according to the present invention, the power source frequency discriminating means automatically discriminates whether the frequency of the commercial power source used is 50 Hz or 60 Hz, and appropriate control parameters are set accordingly. Phase control of the temperature control device is executed. Therefore, the user does not have to worry about the power supply frequency at all, and even when the analyzer is moved across an area where the power supply frequency is different, highly accurate temperature control is achieved. Thereby, the temperature-dependent analysis is performed with high accuracy.

  Specifically, as the power frequency discriminating means in the analyzer according to the present invention, one having the same configuration as the power frequency discriminating device can be used. Thereby, appropriate temperature control according to the power supply frequency is achieved as described above without requiring a large additional cost.

  Hereinafter, a liquid chromatograph mass spectrometer (LC / MS), which is an analyzer equipped with a power frequency discriminating apparatus according to an embodiment of the present invention, will be described with reference to FIGS.

  FIG. 1 is an overall configuration diagram of the LC / MS. The analysis unit 1 is a part that actually performs analysis on a sample and acquires a detection signal. The detection signal is sent to the data processing unit 3 and data processing is executed based on a predetermined algorithm. The analysis unit 1 includes a heater 2. As described above, the heater 2 is a heater attached to a thermostatic chamber that houses a vacuum chamber containing a flight space in a time-of-flight mass spectrometer, for example. The heater 2 is heated by the power supplied by the heating power control unit 4.

  The heating power control unit 4 includes a switch unit 42 including a semiconductor power switch that passes or blocks an AC current supplied from the commercial AC power source 7 and a phase control unit 41 for controlling on / off of the switch. Including. Specifically, the phase control unit 41 uses PWM control to generate a signal that determines the timing for turning on / off the switch. The control unit 6 is a microcomputer or the like and sets various parameters necessary for the control to the phase control unit 41. The power source frequency discriminating unit 5 has a function of discriminating the frequency of the commercial AC power source, and gives the discrimination result to the control unit 6.

  FIG. 2 is a circuit configuration diagram of the main part of the power frequency determining unit 5 in FIG. The zero-cross detection circuit 10 and the PWM control signal generation unit 11 are included in a part of the phase control unit 41, but here, the power frequency discrimination function is realized by using these functions in part. That is, the zero cross detection circuit 10 detects a zero cross point of the commercial AC voltage waveform and generates a pulse signal having a predetermined width (hereinafter referred to as a zero cross detection signal). When the power supply frequency is 50 Hz, the zero cross detection signal is periodically generated every 10 ms, and when the power supply frequency is 60 Hz, the signal is periodically generated every 8.33 ms.

  The PWM control signal generation unit 11 uses a zero cross detection signal as a trigger, and according to a parameter given from the control unit 6 (or according to a parameter set in advance in a built-in ROM or the like), a predetermined position corresponding to the count of the basic clock A pulse signal having a predetermined width is generated. Specifically, the PWM control signal generation unit 11 outputs a pulse signal corresponding to the control angle to an output terminal PWM1 (not shown). On the other hand, a pulse signal for controlling the flip-flop circuit 12 is output using the output terminal PWM2 that is not used for phase control. The flip-flop circuit 12 uses the zero cross detection signal as a clock signal (clock input terminal CK), and uses the pulse signal from the PWM control signal generator 11 as a reset signal (reset input terminal RST).

  The signal output to the output terminal PWM2 will be described in detail. The PWM control signal generator 11 starts counting a 2 MHz basic clock using the input signal of the trigger input terminal TRG2 as a trigger, and outputs an “L” or “H” level to the output terminal PWM2 according to the count value. The correspondence between the count value and the level is set in advance as a parameter. By appropriately setting this parameter, a pulse signal having a predetermined time width can be generated after a predetermined time has elapsed after the trigger is input. . This is the same as the digital implementation of the retriggerable one-shot multivibrator function. Specifically, here, a setting is made so that a pulse signal having a time width of about 2 ms is generated after 8.7 ms has elapsed from the rising edge of the zero-cross detection signal. Since it is retriggerable, if a zero cross detection signal is input during this 8.7 ms, the count of the basic clock until then is reset, and the count starts again from that point.

  Next, the operation of determining the power supply frequency in the power supply frequency determining unit 5 will be described with reference to FIG.

(1) When the power supply frequency is 60 Hz As described above, the zero cross detection signal is generated about every 8.33 ms (see FIGS. 3A and 3B). The PWM control signal generator 11 starts counting the basic clock from the rising edge of the zero cross detection signal, but the next zero cross detection signal is input before counting the number of clocks corresponding to 8.7 ms. Therefore, as a result, the signal level of the output terminal PWM2 is always “H”. That is, the reset input terminal RST of the flip-flop circuit 12 does not receive an “L” level signal for resetting its internal state, and the flip-flop circuit 12 receives the rising edge of the zero-cross detection signal. Every time, the “H” level input to the data input terminal DATA is latched. As a result, the “H” level is always output to the positive output terminal Q of the flip-flop circuit 12.

(2) When the power supply frequency is 50 Hz As described above, the zero cross detection signal is generated every 10 ms (see FIG. 3C). The PWM control signal generator 11 starts counting the basic clock from the rising edge of the zero cross detection signal, but when the number of clocks corresponding to 8.7 ms is counted, the signal level of the output terminal PWM2 is “H” → “L”. To change. Along with this, the internal state of the flip-flop circuit 12 is reset.

  When the next rising edge of the zero-cross detection signal is input to the PWM control signal generator 11, the signal level of the output terminal PWM2 is still “L”, but when the zero-cross detection signal is input, “L” → “H” ”And starts counting the basic clock again from the beginning. Here, there is a time delay by td in the PWM control signal generator 11 from when the zero-cross detection signal rises until the signal level of the output terminal PWM2 changes (see FIG. 3D). For this reason, in the flip-flop circuit 12, the reset input terminal RST is still “L” at the rising edge of the zero cross detection signal input to the clock input terminal CK. Therefore, the internal state of the flip-flop circuit 12 is in a reset state, and an “H” level signal is not read from the data input terminal DATA. As a result, the “L” level is always output to the positive output terminal Q of the flip-flop circuit 12.

  As described above, in the power supply frequency discriminating unit 5, the output level of the positive output terminal Q of the flip-flop circuit 12 is “H” level when the power supply frequency is 60 Hz, and “L” level when the power supply frequency is 50 Hz. become. The control unit 6 determines the level of this signal and gives a control parameter corresponding to the power supply frequency to the phase control unit 41. Thereby, phase control according to the power supply frequency is realized.

As the PWM control signal generator 11, a PWM control IC can be used. An example of this type of IC is M66240 (Mitsubishi Electric). When this M66240 is used, the operation as described above can be achieved by setting parameters as follows.
SUBCONT PWM2 data address: 30038H
Code address: 30039H
Mode selection: Mode1
Prescaler value: L = 4
PWM value: M = 3480
H width polarity: 1 ("H" level)
External trigger selection: 1 (ON)
PWM number selection: 01 (PWM2)
Command 1: AF
Command 2: 22
Prescaler value High byte: 00
Prescaler value Lower byte: 04
Command 2: 2E
PWM value High byte: 0D
PWM value lower byte: 98

  The above-described embodiment is an example of the present invention, and it is apparent that the present invention is encompassed by the present invention even if appropriate changes, modifications, or additions are made within the scope of the present invention. For example, although the above embodiment is an example in which the analyzer according to the present invention is applied to LC / MS, the present invention may be applied to other analyzers that similarly require high-precision temperature control.

1 is an overall configuration diagram of an LC / MS having a power frequency discrimination function according to an embodiment of the present invention. The circuit block diagram of the principal part of the power supply frequency discrimination | determination part in FIG. FIG. 3 is a timing waveform diagram for explaining the operation of the power supply frequency determination unit in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Analysis part 2 ... Heater 3 ... Data processing part 4 ... Heating electric power control part 41 ... Phase control part 42 ... Switch part 5 ... Power supply frequency discrimination | determination part 6 ... Control part 7 ... Commercial alternating current power supply 10 ... Zero cross detection circuit 11 ... PWM Control signal generator 12 ... flip-flop circuit

Claims (4)

a) zero-cross detection means for detecting a zero-cross point of a commercial AC voltage waveform and generating a first pulse signal;
b) The output level is inverted after the time corresponding to the zero cross generation time interval when the commercial AC power supply frequency is 60 Hz with reference to the appearance position of the edge of the first pulse signal, and the commercial AC power supply frequency Pulse signal generating means for generating a second pulse signal whose output level is inverted again after the edge generation timing of the next first pulse signal when the frequency is 50 Hz;
c) A flip-flop that reads the “H” level or the “L” level as data using the edge of the first pulse signal as a clock signal, and resets or sets the internal state by the second pulse signal in preference to the clock signal. Means,
A power frequency discriminating apparatus comprising: In a temperature control device that includes the power frequency discriminating device according to claim 1 and performs temperature control by controlling AC power by phase control with respect to commercial AC power,
The zero cross detecting means detects a zero cross point of a commercial AC voltage waveform for the phase control, and the pulse signal generating means is a pulse corresponding to a control angle based on the appearance position of the edge of the first pulse signal. A temperature control circuit that uses a function of a PWM control circuit for generating a signal, and includes a parameter setting unit that changes a control parameter for the phase control in accordance with an output level of the flip-flop unit. Preparation device. In an analyzer having a temperature control device that performs temperature control by controlling AC power by phase control with respect to commercial AC power,
a) a power frequency discriminating means for judging whether the frequency of the commercial AC power is 50 Hz or 60 Hz;
b) parameter setting means for changing the control parameter of the phase control according to the determination result of the power supply frequency;
An analysis apparatus comprising: 4. The analyzer according to claim 3, wherein the power source frequency discriminating means is
a) zero-cross detection means for detecting a zero-cross point of a commercial AC voltage waveform and generating a first pulse signal;
b) The output level is inverted after the time corresponding to the zero cross generation time interval when the commercial AC power supply frequency is 60 Hz with reference to the appearance position of the edge of the first pulse signal, and the commercial AC power supply frequency Pulse signal generating means for generating a second pulse signal whose output level is inverted again after the edge generation timing of the next first pulse signal when the frequency is 50 Hz;
c) A flip-flop that reads the “H” level or the “L” level as data using the edge of the first pulse signal as a clock signal, and resets or sets the internal state by the second pulse signal in preference to the clock signal. Means,
The zero-cross detection means detects a zero-cross point of a commercial AC voltage waveform for the phase control, and the pulse signal generation means sets the control angle based on the appearance position of the edge of the first pulse signal. An analyzer using a function of a PWM control circuit for generating a corresponding pulse signal.

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