JPS5863097A - Controlling method for stepping motor - Google Patents

Abstract

PURPOSE:To lower the response frequency of a stepping motor and a control system, by conducting 1-2 phase excitation when the number of steps to be transferred is small, while conducting 2-phase excitation when said number is large. CONSTITUTION:Step data, which show the number of steps whereby a carriage driving stepping motor is transferred in a printer, are inputted in an input buffer 11 and set in a difference counter 12. According to whether or not the step data show the number of steps more than the prescribed, it is decided that the stepping motor is subjected to 2-phase excitation or 1-2 phase excitation. In the case when the step data inputted in the input bufer 11 show 20 steps or more, for instance, a clock pulse for 2-phase excitation from a 2-phase pulse generator 15 is inputted in a sequence counter 16, and when the step data show not more than 20 steps, a clock pulse for 1-2 phase excitation is inputted in the sequence counter 16 via an OR circuit 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stepping motor control system used for driving a carriage of a printer, etc.

When a stepping motor is used to move the carriage in a printer and is excited in two phases, the maximum printable length in the horizontal direction is 13.611. In order to satisfy the condition of minimum lateral resolution of 1/120'' and move the entire carriage in time t, the response frequency f of the stepping motor and its control system can be determined from Fig. 1(a) when the stepping motor is driven in all triangles. to, l/120 to, and when the stepping motor is driven entirely trapezoidally, the first
As can be seen from Figure 1), it becomes 16 2 (1-a). Therefore, the stepping motor and control system are to,
A device that can respond to a high frequency of to2(1-a) is required.

Furthermore, when the stepping motor is excited in 1-2 phases to satisfy the above conditions, the response frequency of the stepping motor is reduced to 1/2 because the stepping motor is excited in 1-2 phases, but the response frequency of the control system is not improved. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a stepping motor control method that can lower the response frequency of both the stepping motor and the control system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below by way of embodiments with full reference to the drawings.

In the embodiment of the present invention, when the number of steps to be moved by the stepping motor is small, the stepping motor is excited in 1-2 phases, and when the number of steps to be moved by the stepping motor is large, it is excited in 2 phases.

Therefore, while maintaining the above-mentioned conditions, the response frequency of the stepping motor and control system can be reduced to 1/2 compared to the case where a conventional stepping motor is excited in two phases by stepping.

FIG. 2 shows an example of a circuit for implementing the present invention, and FIG. 5 is a flowchart thereof.

Step data indicating how many steps to move the stepping motor for driving the carriage in the printer is input to the manual buffer 11 and counted by the difference counter 12, and this step data is used to set the predetermined number of steps (20 steps in this example). Depending on whether or not the above conditions are met, it is determined whether the stepping motor is to be excited in two phases or in one to two phases. In other words, when the step data input to the manual buffer 11 is 20 steps or more, the start phase determination circuit 13 determines the entire current excitation status of the stepping motor, and if the stepping motor is stopped with one phase excitation, the one-shot pulse generator is activated. 14 is fully driven and the clock pulse for 1-2 phase excitation is set to 1.
After the two-phase pulse generator 15 has been generated, the two-phase pulse generator 15 is started and two
A clock pulse for phase excitation is sent to the sequence counter 16. The 1-2 phase excitation clock pulse from the one-shot pulse generator 14 is sent to the sequence counter 16 via the OR circuit 17. Sequence counter 16 is 1
- An excitation pulse door for each phase as shown in FIG. 3 by inputting a clock pulse for two-phase excitation.

~14* is generated, and this excitation pulse ~φ4 is generated alternately for one phase and for two phases at the input of a clock pulse. The drive circuit 18 uses this excitation pulse to excite each phase winding 191 to 194 of the stepping motor to move the stepping motor. In other words, the stepping motor moves one step at a time by repeating l-phase excitation and two-phase excitation. I'll go. Therefore, when the tearing motor is stopped with 1-phase excitation and one clock pulse for 1-2 phase excitation is output from the one-shot pulse generator 14, it moves one step and enters the 2-phase excitation state. . In addition, the sequence counter 16 generates excitation pulses for each phase, ~ψ2, as shown in FIG.
This excitation pulse causes each phase winding 19. ~194't2
The stepping motor is moved one step at a time by sequentially energizing each step.

When the stepping motor is stopped due to two-phase excitation, the start phase determination circuit 13 activates the start phase pulse generator 1.
The two-phase pulse generator 15 is started without driving the pulse generator 4. The differential counter 12 counts down the step data by l steps using the 1-2 phase excitation clock pulse from the OR circuit 17, and counts down by 2 steps using the 2-phase excitation clock pulse from the 2-phase pulse generator 15. When the content of the differential counter 12 becomes 1 or less,
The two-phase pulse generator 15 stops operating and the step motor stops. In this case, when the content of the differential counter 12 becomes 1, the remaining step number judgment circuit 20 detects this and drives the one-shot pulse generator 14 to generate a clock pulse for 1-2 phase excitation, thereby driving the stepping motor t. -Move 1 step to 7 steps.

On the other hand, the step data that was not input into the human buffer 11 is 2.
If the step is not 0 or more, the 1-2 phase pulse generator 21 sends the 1-2 phase excitation clock pulse to the t-7 circuit 1'7'.
The sequence counter 16 and the difference counter 12
to move the stepping motor, and when the content of the difference counter 12 becomes 0, the 1-2 phase pulse generator 21
stops working.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, the present invention is a method of switching between 2-phase excitation and 1-2 phase excitation of a stepping motor depending on whether the number of steps to be moved is large or small, and the number of steps is large. In this case, a method may be adopted in which the stepping motor is excited in the t-2 phase, and when the remaining number of steps to be moved reaches a predetermined number of steps, all the stepping motors are excited in the 1-2 phase.

As described above, according to the present invention, when the number of steps to be moved to the stepping motor is small, full 1-2 phase excitation is performed, and when the number of steps to be moved is large, 2-phase excitation is performed, so that the stepping motor and control The response frequency of the system can also be lowered. In addition, when driving a printer's carriage, it has been proposed to use gears in the drive system to use a low-cost motor, but if a stepping motor is used in this method, the faster the response frequency, the lower the motor torque. However, there is a limit to the cost reduction of the stepping motor drive system including the motor due to the problem of response frequency. However, in the present invention, since the response frequency can be lowered, the driving conditions can be satisfied with an inexpensive motor.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the conventional system, Fig. 2 is a block diagram showing an embodiment of the present invention, and Figs. 3 to 5 are timing charts and diagrams for explaining the operation of the same embodiment. 70
-It is a chart. 11...Manual buffer, 12.°° difference counter, 15...2-phase pulse generator, 16...
- Sequence counter, 21...1-2 phase pulse' generator.

Claims (1)

[Claims] A stepping motor control system characterized in that when the number of steps to be moved by the stepping motor is small, 1-2 phase excitation is performed, and when the number of steps to be moved is large, 2-phase excitation is performed.