JP2544774B2 - Motor control circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a motor control circuit for controlling the rotation speed and rotation position of a motor of a machine tool.

[Prior Art] Recently, digital control, which does not change the characteristics with respect to temperature, has become the mainstream for controlling the rotational speed and rotational position of motors of machine tools and manufacturing equipment. For example, a method using 8 bits) is often adopted. FIG. 2 shows a conventional example, in which drive data is calculated by a general-purpose 8-bit microprocessor 1 based on given control data, and the microprocessor 1
The drive data output from the D / A conversion circuit 2 is converted into an analog voltage, and the V / F conversion circuit 3 forms a drive signal having a frequency corresponding to the analog voltage. The speed and rotation of the motor 5 are controlled via the motor. In the figure, 1a is a 16-bit register provided in the microprocessor 1 so that 12-bit data can be output as drive data in order to increase the resolution of speed setting. The drive data is sent to the D / A conversion circuit 2 via the I / O port 1b. In addition, the microprocessor 6
The control program of is stored.

FIG. 3 shows another conventional example, in which 8-bit data is output from the microprocessor 1 in two steps, and the latch timing is controlled by the control circuit 8.
The 12-bit drive data can be input to the D / A conversion circuit 2 via the.

Further, FIG. 4 (a) shows still another embodiment, in which the microprocessor 1 directly forms drive pulses as shown in FIG. 4 (b), and the motor 5 is driven via the driver circuit 4. The drive signal is I / O.
The data is output to the driver circuit 4 via the O port 1b. In this case, the set times T ₁ , T ₂ , T _3, ... Of the timer T provided in the microprocessor 1 are stored in the RAM 7, and based on the program stored in the ROM 6.
Speed data stored in RAM7 (setting time T ₁ , T ₂ , T ₃ …
...) every time the timer T is operated and the time is up
The output of the I / O port 1b is inverted and a drive pulse is output. If acceleration / deceleration is required, RA
The rotation speed of the motor 5 can be changed by providing a table for acceleration / deceleration in M7, sequentially taking out and setting it in the timer T.

FIG. 5 (a) shows still another embodiment, in which the oscillation frequency of the clock oscillator 10 is set by setting data from the microprocessor 1 instead of the programmable timer T of the fourth embodiment. By using programmable dividers 11a and 11b which generate 1 / n drive pulses, a relatively high-speed drive pulse as shown in FIG. 5 (b) can be output. Note that the frequency division data T _A , T _B , T _C, ... Set in the dividers 11a, 11b are
It is stored in RAM7.

[Problems to be Solved by the Invention] However, in the embodiment shown in FIG. 2 described above, the number of bits of drive data is increased in order to set the rotational speed with high accuracy and increase the resolution. In this case, a large number of I / O ports 1b are occupied to output the drive data, and the driver error signal,
There is a problem that input / output of other signal data such as limit signal and emergency stop signal cannot be performed. On the other hand, in the conventional example shown in FIG. 3, since the 8-bit data is input to the D / A conversion circuit 2 in two steps, it takes a long time to transfer the data, the execution speed becomes slow, and the rotation speed increases. There was a problem that I could not increase the speed.

Further, in the conventional example shown in FIG. 2 and FIG. 3, although the resolution in the case where the rotation speed is high can be increased by increasing the bit number of the drive data, the resolution in the case where the rotation speed is low is improved. There was a problem that it became relatively low. For example, if the drive data is 12 bits and all bits are "1", V / F
If the frequency of the signal output from the conversion circuit 3 is set to 200 KHz, the set frequency pitch is 24.4 Hz (= 200
× 1000 / (2 ¹³ -1)), which is 24.4, 48.8, 73.2 ………
199975.5, 200000.0Hz can be set. However, there is a problem in that the set value at a low frequency changes significantly (2 times, 3 times ...), and fine control of the rotation speed cannot be performed.

Furthermore, in the conventional example shown in FIG. 4, since the period of the drive pulse is set by the programmable timer T provided in the microprocessor 1 and the rotation speed of the motor 5 is changed, The speed is limited to the processing speed of the microprocessor 1 and is limited to several tens KHz to 100 KHz, and when controlling a plurality of motors 5, there is a problem that the controllable rotation speed becomes slower.
On the other hand, in the conventional example shown in FIG. 5, although a relatively high rotation speed can be set, expensive dividers 11a and 11b that can perform high-speed calculation are required, and therefore the cost is high. was there.

The present invention has been made in view of the above points, and it is an object of the present invention to perform high-resolution control of high rotation speed with a general-purpose inexpensive microprocessor, and further fine control of low rotation speed. It is to provide a motor control circuit capable of performing

[Means for Solving the Problem] The motor control circuit of the present invention calculates the drive data of the motor based on the given control data, and when the motor is driven at a rotation speed equal to or higher than a predetermined speed, the first The drive data that specifies the rotation speed is output through the I / O port of, and when the motor is driven at a rotation speed lower than the predetermined speed, the serial pulse train for driving the frequency corresponding to the rotation speed is output as the second I / O port. When outputting from the / O port and generating the motor drive output from one I / O port, output from the first I / O port with the microprocessor that fixes the output of the other I / O port D / A conversion circuit that converts the drive data to an analog voltage, a V / F conversion circuit that generates a drive signal that consists of a pulse train with a frequency that corresponds to the analog voltage, the output state of the V / F conversion circuit, and the 2 I / O port output status It is composed of a gate circuit that allows the same output to pass an unfixed output, and a driver circuit that drives the motor by using a serial pulse train output from the gate circuit as a drive signal.

[Operation] In the present invention, the drive data of the motor is calculated based on the given control data, and when the motor is driven at the rotation speed higher than the predetermined speed, the rotation speed is designated through the first I / O port. When driving the motor at a rotation speed lower than the above-mentioned predetermined speed, a serial pulse train for driving having a frequency corresponding to the rotation speed is output from the second I / O port and one of the I When the motor drive output is generated from the / O port, the microprocessor that fixes the output of the other I / O port and the drive data output from the first I / O port are converted to analog voltage. D / A converter circuit, a V / F converter circuit that generates a drive signal consisting of a pulse train with a frequency corresponding to the analog voltage, the output state of the V / F converter circuit, and the output of the second I / O port. The output is not fixed depending on the status. Since it consists of a gate circuit that drives the motor and a driver circuit that drives the motor using the serial pulse train output from this gate circuit as a drive signal, it is possible to control a high rotation speed with high resolution using a general-purpose inexpensive microprocessor. Moreover, it is possible to provide a motor control circuit capable of finely controlling a low rotation speed.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which drive data of the motor 5 (12 in the embodiment) is obtained based on given control data.
Bit), a D / A conversion circuit 2 for converting drive data from the microprocessor 1 into an analog voltage, and a V / V generating a drive signal composed of a pulse train having a frequency corresponding to the analog voltage. A pulse train output from the V / F conversion circuit 3 in a motor control circuit similar to the conventional example that is configured by an F conversion circuit 3 and controls the motor 5 via the driver circuit 4 by a drive signal, A gate circuit 13 that takes a logical product (a logical product in the embodiment, but may be a logical sum) with a pulse train output from a specific I / O port 1b ′ of the microprocessor 1 is provided, and when the output frequency is high, The output from the V / F conversion circuit 3 is output as a drive signal, and the output from the microprocessor 1 is output as a drive signal when the output frequency is low. Here, when the gate circuit 13 outputs drive data “0” from the microprocessor 1, V / F
When the output of the conversion circuit 3 becomes "H", the logical product is taken and
When the output of the V / F conversion circuit 3 becomes "L", the logical sum is formed.

The operation of the embodiment will be described below. Now, assuming that the output of the V / F conversion circuit 3 becomes "H" when "0" is output from the microprocessor 1, the AND operation is performed in the gate circuit 13 to control the motor 5 at a high rotation speed. In that case, “H” is output to the I / O port 1b ′ of the microprocessor 1 so that the output of the V / F conversion circuit 3 is directly output as a drive signal and input to the D / A conversion circuit 2. The drive data is output from the I / O port 1b, and the motor 5 is driven via the driver circuit 4 by the signal output from the V / F conversion circuit 3.

On the other hand, when controlling the motor 5 at a low rotation speed of tens of kHz or less, set "0" to the D / A conversion circuit 2 and set V
The output of the / F conversion circuit 3 is set to "H", a timer T formed by a program in the microprocessor 1 is operated, and the timer time is set to a predetermined value. At this time, the timer T
If the output of the I / O port 1b 'is inverted when the time elapses, a drive signal composed of a pulse train directly controlled by the microprocessor 1 is output, and the motor 5 is driven via the driver circuit 4. It has become so.

Therefore, even when the motor 5 is controlled at a low rotation speed, fine control can be performed by appropriately setting the timer time of the timer T formed in the microprocessor 1, so that from the constant speed to the high speed. High resolution control is possible.

[Effect of the Invention] According to the present invention, the drive data of the motor is calculated based on the given control data, and when the motor is driven at the rotation speed higher than the predetermined speed, the rotation speed is obtained through the first I / O port. When driving the motor at a rotation speed lower than the above-mentioned predetermined speed, a series pulse train for driving the frequency corresponding to the rotation speed is output from the second I / O port. When the motor drive output is generated from the other I / O port, the microprocessor that fixes the output of the other I / O port and the drive data output from the first I / O port are converted into analog voltage. D / A conversion circuit that converts to a V / F conversion circuit that generates a drive signal that consists of a pulse train with a frequency that corresponds to the analog voltage, the output state of the V / F conversion circuit, and the second I / O port Output that is not fixed according to the output status Since it is composed of a gate circuit for passing through and a driver circuit for driving the motor by using the serial pulse train output from this gate circuit as a drive signal, a general-purpose inexpensive microprocessor can be used to control high rotation speed with high resolution. There is an effect that it is possible to provide a motor control circuit that can perform fine control at a low rotation speed.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a block circuit diagram showing a schematic configuration of a conventional example,
FIG. 3 is a block circuit diagram showing a schematic configuration of another conventional example,
FIG. 4 (a) is a block circuit diagram showing a schematic configuration of still another conventional example, FIG. 4 (b) is an operation explanatory diagram of the same, and FIG. 5 (a) is a schematic configuration of yet another conventional example. FIG. 5 (b) is a block circuit diagram showing the schematic configuration of the above operation explanatory diagram. 1 is a microprocessor, 2 is a D / A conversion circuit, 3 is a V / F conversion circuit, 4 is a driver circuit, 5 is a motor, and 13 is a gate circuit.

Claims (1)

(57) [Claims] 1. A drive for designating a rotation speed through a first I / O port when the motor drive data is calculated based on given control data and the motor is driven at a rotation speed higher than a predetermined speed. When data is output and the motor is driven at a rotation speed lower than the above specified speed, a serial pulse train for driving with a frequency according to the rotation speed is output from the second I / O port and one of the I / Os is output. When the motor drive output is generated from the port, the microprocessor that fixes the output of the other I / O port and D that converts the drive data output from the first I / O port into an analog voltage / A conversion circuit, V / F conversion circuit that generates a drive signal consisting of a pulse train with a frequency corresponding to the analog voltage, output state of the V / F conversion circuit, and output state of the second I / O port Output is not fixed according to Motor control circuit comprising a chromatography preparative circuit, a driver circuit for driving the motor to a serial pulse train as a driving signal outputted from the gate circuit.