JP3353923B2 - Aperture control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope provided with an automatic aperture mechanism, and more particularly to an aperture control apparatus capable of controlling the aperture mechanism with good operability by an encoder input.

[0002]

2. Description of the Related Art As an optical system in a microscope, when observing a sample on a stage by an observation system, there is a system in which illumination light is obtained by switching between a transmission illumination system and an epi-illumination system as necessary. The transmission illumination system and the epi-illumination system are provided with a field stop and an aperture stop for the purpose of adjusting the illuminated range and adjusting the numerical aperture of the illumination system.

Conventionally, when the field stop and the aperture stop provided in such an illumination system are controlled by an automatic stop, an automatic switching method in which the opening / closing operation of the stop is switched in conjunction with an objective switching operation and the like, and a case where an opening / closing operation of the stop are required. There are two cases of the manual operation method.

[0004]

In such automatic aperture control, in order to electrically adjust the aperture to a predetermined position by the latter manual operation method, two switches for opening and closing the aperture are alternately operated. There is a problem that operability is poor because the adjustment is performed while pressing. SUMMARY OF THE INVENTION It is an object of the present invention to provide an aperture control device capable of realizing an operational feeling close to a normal manual operation and obtaining extremely excellent operability.

[0005]

The present invention has the following configuration to achieve the above object.

[0006] An invention corresponding to claim 1 is an electrically drivable aperture mechanism provided in an optical system of a microscope,
A stepping motor for driving the aperture mechanism to open and close; a motor drive circuit for supplying a current to the stepping motor; a position detection element for detecting the aperture opening and closing position of the aperture mechanism; and an encoder required for the aperture opening and closing operation of the aperture mechanism An encoder operating unit that outputs data according to, and the output data from this encoder operating unit is taken in at regular intervals of sampling time, and the number of pulses according to the difference between the previous sampling data and the current data is obtained. Based on the position data from the position detection element ,
A predetermined voltage for driving the stepping motor according to the value
Set the current values, and a control means for controlling the throttle mechanism and outputs at equal intervals in the motor drive circuit before them in a speed range which is determined by the characteristics of the stepping motor into the next sampling time It is a thing.

According to a second aspect of the present invention, there is provided an electrically drivable diaphragm mechanism provided in an optical system of a microscope;
A stepping motor for driving the aperture mechanism to open and close; a motor drive circuit for supplying a current to the stepping motor; a position detection element for detecting the aperture opening and closing position of the aperture mechanism; and an encoder required for the aperture opening and closing operation of the aperture mechanism And an encoder operating section for outputting data according to the above. The output data from the encoder operating section is fetched for each pulse, and the difference between the interval at which the previous pulse is input and the interval at which the current pulse is input is determined. On the basis of the position data from the position detecting element , according to the difference between the intervals of the pulse obtained.
To set a predetermined current value for driving the stepping motor.
Constant and is them and control means for controlling the said output to the motor drive circuit diaphragm mechanism in a speed range which is determined by the characteristics of the stepping motor.

[0008]

In the aperture control device according to the first aspect of the present invention, data from the encoder operation section is read at a fixed sampling period, and the difference between the data at the previous sampling and the current data is obtained. based on the position data from the position detecting device seeking the number of pulses corresponding to, determined
Drive the stepping motor according to the value of the pulse number
Set a predetermined current value to operate the motor drive circuit
And outputs at equal intervals before in speed range determined by the characteristics of the motor into the next sampling time by controlling the stepping motor, by operating the diaphragm mechanism, the good operability electric throttle control by encoder input It becomes possible, and its operability is equal to or higher than that of the manual aperture device, and the operability can be improved .

In the aperture control device according to the second aspect of the present invention, data from the encoder operation unit is taken in every pulse, and the interval at which the previous pulse was input and the current pulse were input. Before the obtained pulse, based on the position data from the position detecting element by calculating the difference from the interval.
Drive the stepping motor according to the difference in the intervals
A predetermined current value is set, these are output to a motor drive circuit within a speed range determined by the characteristics of the stepping motor to control the stepping motor, and the aperture mechanism is operated, so that an operable electric aperture is provided by an encoder input. Control becomes possible, and the operability is equal to or more than that of the manual aperture device, and the operability can be improved .

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

First, an example of an optical system of a microscope which is the basis of the present invention will be described with reference to FIG. In FIG. 2, reference numerals 1 and 21 denote light sources such as halogen lamps;
7 and 28 are collector lenses, 3 and 23 are filter units, 4 and 25 are field stops, 5 and 24
Is an aperture stop.

Numeral 6 denotes a condenser lens, numeral 7 denotes a stage, and numeral 8 denotes a unit 8a attached to a revolver 9, respectively.
An objective lens composed of 8b and 8c. Here, the light source 1, the collector lens 2, the filter unit 3, the field stop 4, the collector lens 28, and the aperture stop 5 form a transmission illumination system, and the light source 21, the collector lens 22, the filter unit 23, the aperture stop 24, The field stop 25 and the collector lens 27 form an epi-illumination system.

Further, reference numerals 10 and 11 denote beam splitters which are removably disposed in the optical path to switch the optical path to an observation system or a photographing system as required, 12 denotes an eyepiece optical system, and 13 denotes a photographing optical system. An eyepiece lens 14 is a beam splitter for dividing a light amount at a fixed rate to a photometric light receiving element 15 through a slit for removing harmful light such as an image forming lens and a flare for photographing, and 16 is an image forming lens and a camera. A beam splitter that divides the amount of light into a film surface of a camera 18 via a shutter 17 and an image pickup device 19 for focus detection via another imaging lens, 20 is a light receiving element such as a TV camera or CCD, and 26 is a light receiving element. The beam splitter is removably disposed in the optical path to perform epi-illumination accordingly.

FIG. 1 is a block diagram showing a schematic configuration example for performing encoder control of the field stop 4, 25 and the aperture stop 5, 24 of the above-mentioned transmission illumination system and epi-illumination system by the aperture control device according to the present invention. It is. In FIG. 1, 3
Reference numeral 3 denotes an aperture mechanism; 32, a stepping motor for operating the aperture mechanism 33; 34, a position detecting element for detecting the aperture position of the limit point when the aperture is fully opened and fully closed to output a signal; Is a control circuit 30 to which data input from the encoder operation unit 29 and limit position data of the position detection element 34 are input.
The control circuit 30 determines the number of pulses for driving the motor and the current value to be supplied from these data. Reference numeral 31 denotes a motor drive circuit that outputs a current supplied to the stepping motor 32 and an excitation signal according to a control signal input from the control circuit 30. In the electric diaphragm control device having such a configuration, the control method of the diaphragm mechanism differs depending on the method of processing data from the encoder operation unit 29.

As one control method, data from the encoder operation unit 29 is read at a constant sampling period, the difference between the data at the previous sampling and the current data is obtained, and the number of pulses according to the difference is calculated. This is given to the motor drive circuit 31. In this case, the pulse applied to the motor drive circuit 31 is output at an equal interval before entering the next sampling cycle at a speed within the maximum speed due to the characteristics of the motor, and the amount of current supplied to the motor is the same as that used to drive the previous motor. Is determined from the difference between the number of pulses at this time and the number of pulses output this time, and the stepping motor 32
Is controlled to operate the aperture mechanism 33.

As another control method, there is a real-time control method in which the stepping motor is operated by one pulse each time one pulse is input from the encoder operation section 29 to the control circuit 30. Also in this control method,
The stepper motor is controlled to operate within the maximum motor speed, and the current value is stored only for the previous interval of the encoder pulse input, and the current value is calculated based on the difference between the current pulse interval and the previous pulse interval. The current value is set based on the difference and the current value obtained from the motor characteristics, and the current value that can cope with acceleration / deceleration is controlled. Regarding these control methods, the former control method is referred to as the first embodiment, and the latter control method is referred to as the second control method.
The details of this embodiment will be described later.

FIG. 3 shows an example of the configuration of the above-mentioned aperture mechanism. This aperture mechanism has a configuration in which a cam 35, an aperture section 41, and a fixed base 42 are continuously arranged on the same optical path. The cam 35 has an annular shape as a whole, and an opening 36 having a center on the optical axis is formed at the center, and a plurality of long holes 37 are radially formed around the opening 36. Aperture part 41
Are a plurality of diaphragm plates 38-1 to 38-8 having the illustrated shape.
Each of the aperture plates 38-1 to 38-8 has an engagement piece 39 inserted into an elongated hole 37 corresponding to the cam 35 on a cam-side surface at one end, and a fixing table 42 at the other end. Has a shaft 40 rotatably inserted into a hole 44 described later.

The plurality of aperture plates 38-1 to 38-8
Are combined around the optical axis such that one surface of each aperture plate is overlapped with the other surface of the adjacent aperture plate. The fixed base 42 has an opening 43 centered on the optical axis, and a hole 44 around which the corresponding shaft 40 of the plurality of diaphragm plates 38-1 to 38-8 is rotatably inserted. ing.

Accordingly, in the aperture mechanism constructed as described above, when the cam 35 is rotated about the optical axis, the aperture plates 38-1 to 38-8 of the aperture section 41 are adjacent to each other about the axis 40. It is possible to change the diameter of the opening formed by the inner peripheral edges of the aperture plates 38-1 to 38-8.

FIG. 4 shows an example of the structure of a mechanism for driving the aperture mechanism shown in FIG. In FIG.
Reference numerals 47 and 47 denote spur gears fixed to both ends of a shaft 45 supported by bearings (not shown), and one of the spur gears 46 meshes with the gear formed on the peripheral portion of the cam 35 described above. Further, the other spur gear 47 is connected to the stepping motor 32.
Are connected via a belt 44 to a spur gear 48 fixed to the rotating shaft 43 of the rotator.

Accordingly, in the drive transmission mechanism having such a configuration, when the motor 32 is driven and the rotation shaft 43 rotates, the spur gear 48 rotates integrally therewith. When the rotation of the spur gear 48 is transmitted to the spur gear 47 via the belt 44,
Since the spur gear 46 rotates via the shaft 45, the cam 35 rotates, and the aperture 38 opens and closes by the mechanism described above. Here, it is possible to set the diameters of the spur gears 46, 47, 48 and the cam 35 to desired values, and obtain an arbitrary deceleration from the step angle of the stepping motor 32.

In this case, the spur gears 46, 47, 48, the shaft 4
The transmission mechanism composed of the belt 5 and the belt 44 is a reduction gear set at a reduction gear ratio such that the cam 35 makes one rotation while the motor makes several rotations, and the rotation can be transmitted at the same reduction ratio. Other configurations may be used as long as they are appropriate.

FIG. 5 shows a first example of the aperture control device described with reference to FIG.
2 is a block diagram showing a configuration example of the embodiment, and the same parts as those in FIG. 2 are denoted by the same reference numerals. In FIG. 5, 90 ° from the optical incremental encoder of the external operation unit 29.
The phase-shifted A-phase and B-phase pulses are sent to the encoder counter 49, and the encoder counter 49 counts these pulses. Further, a CPU is used as the control circuit 30, and this CPU 30
a, an output port 30b, a D / A converter 30c, an external interrupt unit 30d, an internal RAM 30e, and an output port 30f.

The output port 30f of such a CPU 30
Sends a read command to the encoder counter 49 from the 8-bit output terminal of the encoder counter 49.
The count data of 16 bits, that is, the lower 8 bits, is output to the input port 30 a of the CPU 30. CPU
Reference numeral 30 denotes a motor which transmits a pulse calculated from the count data taken into the input port 30a to the motor drive circuit 31 from the output port 30b, and simultaneously outputs a reference voltage Vref which is a reference of a current flowing from the A / D converter 30c to the motor. It is sent to the voltage reference terminal Vref of the circuit 31. The motor driving circuit 31 supplies the two-phase unipolar stepping motor 3
2 is supplied with electric current, the motor rotates and the aperture mechanism 33
Opens and closes.

The limit point when the aperture mechanism 33 is fully opened and fully closed is detected by a photo interrupter 34 used as a position detecting element, and an external interrupt section 30d of the CPU 30 is provided.
Sent to When a fully open limit point detection signal or a fully closed limit point detection signal is input to the external interrupt unit 30d, the CPU 30
The motor 32 is controlled so as not to operate in a direction exceeding the limit point. In this case, the CPU 30 searches for the position of the aperture, and detects whether or not a signal output when the aperture mechanism 33 is fully opened from the position detecting photointerrupter 34 at the time of initialization is input. The motor 32 is driven until the aperture is fully opened, and the position at which the signal at the time of full opening from the photo-interrupter 34 is input to the external interrupt unit 30d is defined as the origin 0.
In the internal RAM 30e. By recording this position data, the current position is grasped by the CPU 30 at any time, and the aperture position is made to be able to correspond to the predetermined position when the objective is switched.

Next, the operation of the aperture control device configured as described above will be described with reference to the flowchart shown in FIG. Now, if the A-phase and B-phase pulses output from the encoder of the external operation unit 29 and shifted by 90 ° are counted by the encoder counter 49, and the sampling time becomes a fixed interval (S1), the encoder counter The 16-bit count data is fetched from 49 (S2), and the value is detected (S3).

Next, the detected value of the count data is the internal R
The difference is obtained by comparing it with the count data of the previous sampling stored in the AM 30e (S4), and if there is a difference, the process proceeds to the next processing (S5), the opening / closing direction of the aperture mechanism 33 is determined, and the position is detected. It is determined whether or not the position data detected by the photo interrupter 34 exceeds the limit point of the fully open and fully closed of the aperture mechanism 33, and if the motor can be driven, the current and previous The difference between the count data is the number of pulses for operating the motor.

Since the motor drive circuit 31 determines the current to be supplied to the motor 32 based on the input voltage value of the voltage reference terminal Vref, the current value to be sent to the motor is the voltage to be sent to the voltage reference terminal Vref of the motor drive circuit 31. CPU3 value
The current value supplied to the motor is changed by changing the value using the D / A converter 30c inside 0. In this case, the reference table of current supplied to the motor when the range of frequencies f ₁ is a torque than 8 is constant f ₁ in FIG. 7
Column.

[0029] Therefore, if the motor is driven with a frequency of up to f ₃ range, f ₃ with the highest frequency torque is small as can be seen from the characteristics of the motor shown in FIG. 8, than the current value of the torque constant f ₁ A lot of current needs to flow.
For this reason, another table is provided in a range where there is a change in torque such as f ₂ and f ₃ , and the current supplied to the motor 32 is set in three stages according to the frequency.

The difference between the encoders shown in FIG. 7 is a value obtained from the difference between the number of pulses sent to the motor at the previous sampling and the number of pulses sent to the motor at the current sampling stored in the internal RAM 30e of the CPU 30. . Based on this value, it is determined whether the acceleration / deceleration action is acting on the motor.
Use this as a guide for whether to supply a large amount of current. As described above, the current value supplied to the motor is set from the table of FIG.

The pulse interval (frequency) sent to the motor drive circuit 31 is equal at intervals as shown in FIG. 9 until the next sampling time is entered in order to smoothly perform the acceleration / deceleration action.
It is output from the PU 30.

Here, the interval and the frequency of the number of pulses to be output within the sampling time are set as follows: When the sampling time is t and the number of pulses is P, the timing at which the first pulse is output from FIG. 2P (1) The pulse interval of the second and subsequent pulses is t / P (2)

The above equation holds. Here, it should be noted that since the maximum value of the number of pulses falling within the sampling time set by the MAX frequency of the motor 32 is determined, an upper limit is set when a pulse is input from the encoder more than that. The point is that even if data exceeding the limit is input, data exceeding the upper limit is ignored and a process of moving the motor at the maximum speed is required.

The pulse and the voltage of the frequency calculated and set by the CPU 30 are sent to the motor drive circuit 31 to drive the motor 32 to operate the aperture mechanism 33 (S6). In this case, the pulse intervals (frequency) sent from the CPU 30 to the motor drive circuit 31 are output at equal intervals as shown in FIG. 9 until the next sampling time in order to smoothly perform the acceleration / deceleration action.

In the above processing, when there is no encoder count data (S2) and the number of times is x times (S7), the excitation to the motor is stopped and the supply current is set to 0A.

As described above, in the first embodiment, the A-phase data and the B-phase data which are shifted by 90 ° from the encoder of the external operation unit 29 are counted by the encoder counter 49, and are counted at a constant sampling time. CPU 30
And the difference between the data at the previous sampling and the data at the current sampling is calculated, and the number of pulses corresponding to the difference is supplied to the motor drive circuit 31 at a speed within a speed range determined by the characteristics of the motor. Before entering, the amount of current supplied to the motor and the amount of current supplied to the motor are determined from the difference between the number of pulses when the motor was driven last time and the number of pulses to be output this time, and the stepping motor 32 is controlled according to the result. Since the aperture mechanism 33 is operated, it is possible to control the electric aperture with good operability by an encoder input, which has not been possible conventionally, and the operability is equal to or higher than that of the manual aperture device, and the operability can be improved. it can. Next, a second embodiment of the electric diaphragm control device according to the present invention will be described with reference to FIG. The same parts as those in FIG. 5 are denoted by the same reference numerals, and different configurations will be described here.

In the second embodiment, A is shifted by 90 ° from the optical incremental encoder of the external operation unit 29.
Phase and B phase data directly to external interrupt unit 30g of CPU 30
To detect both the rise and the fall, and to set a flag when one of the interrupts occurs, and to output a one-pulse excitation signal and a reference voltage set in the motor drive circuit 31 when the flag is set. It was made. Therefore, the two-phase unipolar stepping motor 32 is
Is supplied to the motor 32, the motor 32
Moves by one pulse, and the diaphragm mechanism 33 operates in synchronization with this. In this case, the limit point at the time when the aperture mechanism 33 is fully opened and fully closed is detected by the photo interrupter 34 for position detection and given to the CPU 30 to provide the CPU 30 with the CPU 30.
Is controlled so that the motor 32 does not exceed the limit point as in the first embodiment described above. Next, the operation of the aperture control device having such a configuration will be described with reference to the flowchart shown in FIG.

When data whose phase is shifted by 90 ° from the encoder of the external operation unit 29 is input to the external interrupt unit 30g of the CPU 30 (S9a), the flag is detected by detecting either the rising or the falling of the data. (S9
b). If it is determined that this flag is set (S
10) The interruption of the encoder data is prohibited only during the maximum frequency of the motor 32 (S11). This is because the motor 32 does not operate even if the next data is input earlier than the interval of the maximum frequency of the motor, so that the interrupt is prohibited in advance and the flag is not set.

Next, the opening / closing direction (forward / reverse rotation direction of the motor) of the aperture mechanism 33 is determined from the difference between the count data of the encoder when the previous pulse was output and the count data of the encoder output this time (S12). Based on the data of the photo-interrupter 34 for detection, it is determined whether or not the data does not exceed the limit of opening and closing of the aperture mechanism 33. If the motor can be driven, an excitation signal and a current to be supplied to the motor 32 are set (S13). This current value is represented by a to a shown in FIG.
The interval of the encoder pulse such as d is stored in the internal RAM 30e of the CPU 30 only for the immediately preceding data, and the difference between the interval at the time of the previous transmission of the pulse and the current transmission and the immediately preceding data is obtained. The current value is determined from the motor characteristic table shown in FIG. FIG.
Looking at the current value shown in the figure, when the difference between the pulse intervals is large, acceleration and deceleration are working, so a large amount of current is flowing, and when the difference is small, constant current motion is performed. I have.

The current is set in this manner, and a voltage at which the set current is supplied to the motor 32 is applied to the motor drive circuit 3.
1 to the voltage reference terminal Vref. Motor drive circuit 3
1 receives the reference voltage and the motor excitation signal,
Is driven (S14), and the aperture mechanism 3 is synchronized with the motor 32.
3 opens and closes. During this time, if it is time to be able to release the interrupt of the encoder data, loop processing is performed (S
15) Continue until interruption is permitted (S16).

The timing at which the excitation signal sent to the motor 32 is stopped and the current sent to the motor 32 is set to 0 is input from the encoder data, the time when the flag is set is stored in the internal RAM 30e, and a set time is provided. If the next flag is not set for a few seconds after the flag is set,
F (S17).

As described above, in the second embodiment, the A of the encoder operating section 29 is shifted by 90 ° in phase from the encoder.
The phase data and the B-phase data are input to the CPU 30, and control is performed to operate the stepping motor 32 by one pulse at a speed within a speed range determined by the characteristics of the motor each time one of the rising and falling of the data is detected. In addition, the current value stores the interval at which the encoder pulse was input only for the previous time, and based on the difference between the current pulse interval and the previous pulse interval, based on the difference and the current value obtained from the motor characteristics, Since the current value that can cope with acceleration and deceleration is determined, and the stepping motor 32 is controlled according to the result to operate the aperture mechanism 33, it is possible to control the aperture with good operability by the encoder input, which was not possible conventionally. Moreover, the operability is equal to or higher than that of the manual aperture device, and the operability can be improved.

In the first and second embodiments described above, an optical incremental encoder is used as the external operation unit 29. However, the same function can be obtained by an optical absolute type or an excitation type encoder. If it can be used, it can be used for the operation unit. Although a photo interrupter was used as the position detecting element 34,
A magnetic sensor or the like may be used. Further, although a two-phase stepping motor is used as a motor, a five-phase stepping motor can be used as long as it is a stepping motor.

On the other hand, by appropriately changing the program of the CPU 30, the response to the motor change, the excitation signal to be sent to the motor, the timing of turning off the current, and the motor being driven by one pulse when four pulses of data from the encoder are inputted, for example. The processing can be easily performed in consideration of the operability of the encoder such as moving.

[0045]

As described above, according to the present invention, it is possible to provide an iris control device capable of realizing an operational feeling close to ordinary manual operation and obtaining extremely excellent operability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example based on a basic concept of an aperture control device according to the present invention.

FIG. 2 is a schematic diagram illustrating an example of an optical system of a microscope.

FIG. 3 is an exploded perspective view showing a configuration example of a diaphragm mechanism.

FIG. 4 is a sectional view showing a configuration example of a mechanism for driving the diaphragm mechanism shown in FIG. 3;

FIG. 5 is a block diagram showing a first embodiment of the aperture control device according to the present invention.

FIG. 6 is an exemplary flowchart showing the operation of the embodiment.

FIG. 7 is a view showing a reference table of a current value supplied to the motor in the embodiment.

FIG. 8 is a characteristic diagram of a motor used in the embodiment.

FIG. 9 is a diagram showing output pulses sent to a motor drive circuit in the embodiment.

FIG. 10 is a block diagram showing a second embodiment of the aperture control device according to the present invention.

FIG. 11 is an exemplary flowchart showing the operation of the embodiment.

FIG. 12 is a timing chart of output data of an encoder in the embodiment.

FIG. 13 is a view showing a table of current values obtained from motor characteristics in the embodiment.

[Explanation of symbols]

29: external operation unit, 30: control circuit (CPU), 3
1 ... motor drive circuit, 32 ... stepping motor,
33 ... Aperture mechanism, 34 ... Position detecting element, 49 ... Encoder counter.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-76330 (JP, A) JP-A-4-69608 (JP, A) JP-A-62-284316 (JP, A) 90216 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 9/00-9/70 G02B 7/02-7/16

Claims (4)

(57) [Claims] 1. An electrically drivable aperture mechanism provided in an optical system of a microscope, a stepping motor for driving the aperture mechanism to open and close, a motor drive circuit for supplying a current to the stepping motor, and the aperture mechanism A position detecting element for detecting the aperture opening / closing position of the aperture mechanism; an encoder operation section for outputting data by an encoder necessary for the aperture opening / closing operation of the aperture mechanism; and output data from the encoder operation section at regular sampling intervals. crowded at the basis of the position data from the position detecting device seeking the number of pulses corresponding to a difference between the data and the current data at the previous sampling, the path obtained
Drive the stepping motor according to the value of the number of rubs
Control means for setting a predetermined current value, outputting these at equal intervals to the motor drive circuit before entering the next sampling time within a speed range determined by the characteristics of the stepping motor, and controlling the aperture mechanism; An aperture control device comprising: 2. An electrically drivable aperture mechanism provided in an optical system of a microscope, a stepping motor for driving the aperture mechanism to open and close, a motor drive circuit for supplying a current to the stepping motor, and the aperture mechanism. A position detecting element for detecting the aperture opening / closing position of the aperture mechanism; an encoder operation section for outputting data by an encoder necessary for the aperture opening / closing operation of the aperture mechanism; The difference between the pulse input interval and the current pulse input interval is calculated based on the position data from the position detecting element, and the calculated pulse interval is calculated based on the position data .
A predetermined voltage for driving the stepping motor according to the difference
A diaphragm control device for setting a flow value , outputting the flow value to the motor drive circuit within a speed range determined by the characteristics of the stepping motor, and controlling the diaphragm mechanism. 3. The method according to claim 2 , wherein the set current value is the stepping current.
Change according to the frequency of the pulse supplied to the motor
The aperture control device according to claim 1, wherein: 4. The method according to claim 1 , wherein the set current value is the stepping current.
Reference table according to the frequency of the pulse supplied to the motor
2. The method according to claim 1, wherein
The aperture control device according to claim 3.