JPS62181696A - Control circuit for stepping motor - Google Patents

Abstract

PURPOSE:To maintain a stepping motor at uniform velocity at desired set velocity, and to enable follow-up even to speed variation by arbitrarily controlling the position of the phase changeover of the angle of stepping acquired by an output from an encoder. CONSTITUTION:A speed detecting section 1 detects speed from an output signal from an encoder, and outputs a speed data. A previously set set-speed data and a detecting speed data from the speed detecting section 1 are compared by a speed comparator 2, and a data regarding the changeover of phase at any angle of a stepping motor is outputted. A phase-changeover timing generating section 3 generates phase-changeover timing by the data from the speed comparator 2 and an output from the encoder. A phase data output section 4 generates a phase data by a signal from the phase-changeover timing generating section 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a step motor control circuit, and more particularly to a step motor speed control circuit.

Prior Art Conventionally, the speed control of a step motor has been performed by so-called open-loop control. Maximum l of motor
-The system detects the torque and thereby shortens the start-up and down-way openings, etc.

In such conventional closed-loop control circuits, a certain fixed [−
Since the phase can only be switched at the evening angle, it is not possible to set an arbitrary speed, and the speed cannot be maintained at a constant speed at an arbitrary set speed.

OBJECTS OF THE INVENTION The present invention has been made to eliminate the drawbacks of the conventional ones, and its purpose is to provide a control circuit for a step motor that can be set at any speed and at a constant speed. .

Step motor t, 11 (20 circuits of the invention) according to the invention
speed detection means for detecting the rotational speed of the step motor;
The detected speed information is compared with the preset setting speed information (l switching timing determining means for determining the switching timing, and the determined switching timing) 11 outputs phase data in accordance with the switching timing (D It is characterized in that it includes a data optical generation means.

Example Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which a speed detection section 1 detects speed from an output signal from an encoder (not shown) and outputs speed data.

The speed comparator 2 compares preset speed data with the detected speed data from the speed detector 1, and outputs data indicating at which angle of the step Tanabata phase the phase should be switched. (The 0 switching timing generating section 3 generates the phase switching timing based on the data from the fast claw comparison section 2 and the encode output.

The phase data output section 4 generates phase data (for example, .phi.1 to .phi.4) based on the signal from the phase switching timing generation section 3.

FIG. 2 is a timing chart showing an example of the operation of the circuit shown in FIG. 1, when the encoder output is 200×6 pulses/rotation. The phase switching timing is sequentially controlled so that the encoder output has two consecutive step angles of 6 pulses, followed by a step angle of 7 pulses, and then a step angle of 5 pulses.1. Then, the waveform of the torque t is as shown in the figure. -'J Straw's torque curve shows the 1'31 gland (the part where 1 step angle is 7 pulses), and the 1 to 1 torque decreases, and the 1 step angle is 6.
If the pulse of f[lJ is continued for 1 time, 1 upper middle crosses and deviates, 1 better becomes 1 j or less. Therefore, compared to the case where the phase switching timing is switched at the same step angle, the torque is reduced, and as a result, the motor speed is also reduced.

Therefore, the comparison unit 2 compares the set speed information +lJ and the detected speed information.
By determining the phase switching timing in the phase switching timing generating section 3 so that the speed becomes the set speed by comparing the speed with the set speed, the phase data φ1 to φ4 shown in FIG. This means that they will be exposed.

In addition, φ3. φ4 is people φ1. It is reverse phase data of φ2,
Not shown.

Effects of the Invention According to the present invention, by arbitrarily controlling the phase switching position of the step motor angle, which is determined by the encoder output by 1!7, it is possible to maintain a constant speed at a desired set speed, and the speed fluctuation This has the effect of making it possible to follow the target.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a timing chart 21 to 21 showing the operation of the blocks in FIG. Explanation of symbols of main parts 1...Speed detection section 2...Speed comparison section 3...Phase switching timing generation section 4...
・Phase data output section

Claims (1)

[Claims] a speed detection means for detecting the rotational speed of the step motor; a switching timing determining means for determining a phase switching timing by comparing the detected speed information and preset speed information; and a switching timing determining means for determining a phase switching timing. A step motor control circuit comprising: phase data generating means for outputting phase data in accordance with the phase data.