JPS622896A - Stepping motor control system - Google Patents

Abstract

PURPOSE:To enable to control a motor without considerably increasing a load of a CPU at high speed rotation time by circularly shifting a shift register by a clock which outputs a timer at high speed rotation time. CONSTITUTION:Since a CPU 1 has a timing margin at low speed rotation time, the CPU 1 can directl handle phase-excitation data. Accordingly, a stepping motor 2 is finely controlled by a half-step drive (1-2-phase excitation) of rull-step drive (1-phase or 2-phase excitation). Full step data are loaded to a shift register 6 at high speed rotation time, the register 6 is circularly shifted by a control signal, and the motor 2 is rotated by a clock input from a timer 5. In this case, the CPU 2 does not necessarily set new phase excitation data in the register 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a stepping motor control system in which a stepping motor is controlled by a microprocessor (hereinafter referred to as CPU).

(Prior Art) Conventionally, there have been systems of this type as shown in FIGS. 4 to 6.

The method shown in FIG. 4 is a method in which the stepping motor 43 is rotated by sequentially setting the phase excitation data stored in the memory of the CPU 41, which determines the rotation angle of the stepping motor, in the register C.

The method shown in FIG. 5 is similar to the method shown in FIG. 4, in which the CPU 51 sequentially sets phase excitation data in the second register 54 and rotates the stepping motor 53t, but a second register 54 and a timer 55 are added. By CPU
This reduces the load on the stepping motor 51 and prevents uneven rotation of the stepping motor 53. FIG. 7 shows a time chart when this control is performed.

The control according to the method shown in FIG. 5 will be explained in detail based on the time chart shown in FIG. 7. First, the CPU 51 sets a timer value n to the timer 55, which determines the phase switching time.

Next, phase excitation data φ1 that determines the first rotation angle is set in the first registor 52. Here, the CPU 51 can execute other tasks.

Meanwhile, the timer 55 continues counting down, and outputs a count end signal when the set content reaches 0. The count end signal acts as a second register set signal to the second register 54, loads the phase excitation data φl previously set in the CPU 51 into the second register 54, and at the same time loads the stepping signal connected to the output of the second register 54. By outputting to the motor 55, it is rotated by a certain angle. On the other hand, the count end signal is input to the CPU 51 as an interrupt signal 57, notifying the CPU 51 that the stepping motor has rotated by a certain angle. The CPU 51 uses the interrupt signal to set the phase switching time nf timer 55 and the phase excitation data φ2 in the first V register 52 for the next rotation as in the -th rotation. This repetition makes it possible to control the rotation of the stepping motor 53.

The method shown in Fig. 6 is a dedicated stepping motor control section 62t.
- This is a system in which the stepping motor 63 is controlled by providing the stepping motor 63.

In this method, control is performed using the following parameters.

■ Phase excitation method (1-phase excitation, ■-2-phase excitation, or 2-phase excitation) ■ Motor rotation direction (forward or reverse rotation) ■ Phase excitation switching timing (problem to be solved by the invention) However, the above three methods Each had the following problems.

First, the method shown in Figure 4 requires the least hardware, but C
The timing when the PU 41 sets the phase excitation data in the register 42 is the timing to change the rotation angle of the stepping motor 430, so when the CPU 41 is performing other tasks (interfacing with the host CPU, etc.), it is necessary to set the exact timing. It becomes difficult to make. Therefore, in this method, the stepping motor 430 rotations are slow and the CPU
41 and is limited to use for light-duty purposes.

In the method shown in FIG. 5, the timing for applying phase data to the stepping motor 53 is determined by the timer 55, so the load on the CPU 51 for rotating the stepping motor 53 is lighter than in the method shown in FIG.

Suitable for relatively high-speed rotation control. However, Thailand-r5
5, each time the phase excitation data of the first register 52 is transferred to the second register 54, the CPU 51 needs to set the next phase excitation data. therefore.

When the stepping motor 53ft is desired to rotate at high speed, the load increases, so if there is a large amount of data to be processed by the CPU 51, a situation may arise where the stepping motor cannot be rotated at high speed.

The method shown in FIG. 6 uses a dedicated LSIt.

The load on the CPU61 is the lightest, but it is the LS that suits the purpose.
It has the disadvantage that it is difficult to obtain I, and it tends to be expensive, and furthermore, in order to create an interface with the CPU 61, the amount of hardware may increase.

The present invention solves the problems of the conventional technology, such as the increase in CPU load during high-speed rotation and the use of a dedicated LSI, as described above, and uses a general-purpose IC without significantly increasing the CPU load during high-speed rotation. An object of the present invention is to provide a stepping motor control method that can perform control.

(Means for Solving the Problems) The present invention relates to a stepping motor control method in which the rotation of a stepping motor is controlled by a microprocessor, and in order to solve the problems of the prior art described above, the rotation angle of the stepping motor is determined. A timer that creates the switching timing of phase excitation data, a register in which the phase excitation data is set by the microprocessor, and a shift register connected to each output of the timer and register are provided. The phase excitation data is loaded into the shift register at the switching timing output by the timer, and during high-speed rotation, the shift register performs a circular shift using the clock output by the timer, and the stepping motor is driven based on the output of the shift register. .

(effect) When rotating a stepping motor at low speed.

The timer is set, and the microprocessor sets phase excitation data in the register.This phase excitation data is loaded into the shift register at the phase excitation timing created by the timer, and the stepping motor is operated based on the output of the shift register. let Therefore, fine-grained control is possible.On the other hand, when performing high-speed rotation, the foot register is circularly shifted by the clock output from the timer, and the stepper motor can be driven at high speed without phase excitation data being set in the register from the microprocessor. It will be done.

Therefore, the load on the microprocessor is reduced during high-speed rotation, and since each means can be realized by a general-purpose LSI or IC, control can be performed at low cost, and the problems of the prior art described above are solved.

(Example) FIG. 1 is a circuit diagram showing an embodiment of the present invention.

In the figure, 1 is a CP that controls the stepping motor 2.
U is configured with LSI such as Intel 8085. As the stepping motor 2, a two-phase motor is used in this case. A data bus 3 of the CPUI is provided with a register 4 for storing phase excitation data of the stepping motor 2 and a timer 5 for setting the timing for switching the phase excitation data. The register 4 and the timer 5 can be configured in one chip using LSItl such as 8253 manufactured by Intel Corporation. A shift register 6 is provided between the register 4 and the stepping motor 2. This shift register 6 stores phase excitation data for directly controlling the stepping motor 2, and is capable of parallel input/parallel output and bidirectional shifting. The shift register 6 can be constructed from an LSI such as 5N74194 manufactured by Texas Instruments. A total of 6 bits, 4 bits of input data and 2 bits of a control signal, of the shift register 6 are supplied from the output terminal of the register 4, and 4 pins of the output of the shift register 6 are supplied to the stepping motor 2. The output of the timer 5 is connected to the clock input (CK) of the shift register 6 and the interrupt input (IN'f')K of the CPUL.

In FIG. 1, 7 is a data line, 8 is a register control line, and 9 is a timer end signal line. Further, FIG. 2 is a diagram showing details of the connection of the shift register 6, and FIG. 3 is a diagram for explaining the operation of the shift register.

Next, the control operation of the stepping motor according to this embodiment will be explained.

First, when performing low-speed rotation, since the CPU has time, the shift register 60 control signal 5o-8tt-8o
By setting =i, 5t=t, the circuit configuration becomes the same as that shown in FIG. 5, and therefore the control becomes the same as that shown in FIG. 7. In this case, since the CPU can directly handle the phase excitation data, the stepping motor 2 is driven by no-step drive (l-
2-phase excitation) or full step drive (l-phase or 2-phase excitation)
It can be operated with fine-grained control.

Next, the case of high-speed rotation will be explained. In this case, full-step driving (one-phase or two-phase excitation) is more advantageous because the one-step angle is double that of half-step driving.

Therefore, full step data is loaded into the shift register 6 and the control signal S is sent. .

Stt”5o=1, S,=O (S in case of reverse rotation
. =0°S, =1), shift register 6
is a circular shift, and the stepping motor 2 can be rotated by the clock input from the timer 5.

In this case, the CPU 1 does not need to set new phase excitation data in the shift register 6. In addition, an LSIt such as Intel 8253 is used as the timer 5, and the LSIt-
If the continuous count mode of the SI timer function is used, timer control such as setting a timer value becomes unnecessary. In this way, the CPU only counts the number of rotation angles due to the interrupt from timer 5! ri, CPU1
The load for controlling the stepping motor 2 is reduced,
Therefore, high-speed rotation control becomes possible.

According to the embodiments described above, by using a general-purpose LSI or IC 11, it is possible to control the rotation of a stepping motor in a wide range from half-step drive at low-speed rotation to high-speed rotation at full-step drive. Further, in the above explanation, a two-phase stepping/stepping motor has been described as an example, but by increasing the number of bits of the register 4, the number of shift registers 6, and the number of pits, it can be applied to other motors other than the two-phase stepping motor.

A wide range of speed control is possible for 4-phase or 5-phase stepping motors.

(Effects of the Invention) As explained above, according to the present invention, C
It becomes possible to control the stepping motor without significantly increasing the load on the PU. In addition, a dedicated LS
Since control can be performed using a general-purpose LSI or IC without using I''t, there is an economical effect.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an embodiment of the present invention, Figure 2 is a diagram showing the connection of the shift register, Figure 3 is an explanatory diagram of the operation corresponding to the control bits of the shift register, and Figures 4 to 6 are conventional diagrams. FIG. 7 is a timing chart of the circuit shown in FIG. 5. ■...Microprocessor (CPU) 2...Stepping motor 4...Register 5...Timer 6...Shift register

Claims (1)

[Claims] In a stepping motor control method in which the rotation of a stepping motor is controlled by a microprocessor, there is provided a timer for creating switching timing of phase excitation data that determines the rotation angle of the stepping motor, and a timer for setting the phase excitation data by the microprocessor. A register is provided, and a shift register is connected to each output of the timer and register. During low speed rotation, the phase excitation data set in the register is loaded into the shift register at the switching timing of the timer output, and during high speed rotation, the phase excitation data set in the register is loaded into the shift register. A stepping motor control method characterized by causing a shift register to perform a circular shift using a clock output from the stepper, and driving a stepping motor based on the output of the shift register.