JPS6011558B2 - How to drive a step motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving method for controlling the rotational direction of a step motor, ie, clockwise or counterclockwise.

Conventionally, a drive circuit for a four-phase step motor has had a circuit configuration as shown in FIG. 1 for clockwise rotation.

That is, a clock pulse as shown in FIG. 2a is input to the input armature 11, and a clock pulse is input to the input terminal 12. A control signal for the number of pulses is input. Then, the output of the AND circuit 13 is applied as a clock signal to the two flip-flop circuits 14 and 15, and the signals shown in FIG. 2b, c. Respective flip-flop circuits I4 and 15 as shown in d and e.
The Q and Q outputs are output as A-phase, B-phase, C-phase and D-phase outputs, respectively. These outputs are rearranged in the order of A, C, B, and D so that the pulses are phase-shifted by 90 degrees, and are sequentially supplied counterclockwise through the solenoid buffers of each phase of the step motor. Then 1 in 1 step
It rotates clockwise in steps of 5 degrees and stops at a predetermined position depending on the number of clock pulses. With this follow-up method, it is impossible to change direction from clockwise to counterclockwise. Therefore, if you want to control counterclockwise as well, a separate external control circuit is required, and this separate The external control circuit had the disadvantage that direction changing operations were troublesome and expensive.

The present invention was made in order to solve the drawbacks of such a dependent system, and uses a register to set different cut-off values depending on the direction of forward or reverse rotation, and also to shift to the left or right. The rotation direction of the step motor is controlled by controlling the rotation direction of the step motor.

That is, in the circuits shown in FIGS. 1 and 2, each phase (
A. B, C, D phase) and step position (1.0, m, W)
The relationship is as shown in Table 1. Table 1 If this is rearranged so that the pulses are phase-shifted by 90 degrees, it can be rewritten as shown in Table 2.

Table 2 It can be seen from Table 2 that when trying to rotate one step clockwise, the initial position is "0011".
That is, it is sufficient to set "3" in the register and perform one left shift.

When this left shift is repeated in sequence, the motor rotates clockwise. Conversely, if you want to rotate one step counterclockwise, set "1001" or "9" as the initial position.
All you have to do is set , and shift to the right once. By repeating this shift to the right one after another, the motor rotates in all directions counterclockwise. From the above, the register and shift control rotation direction can be controlled. Hereinafter, one embodiment of the present invention will be described based on the drawings from FIG. 3 onwards.

Step motor: 2 rivers, 4 poles, 24 steps per revolution.
An example in which one step rotates by 15 degrees will be explained.

21 is a register such as an accumulator, and since the motor has four phases, it has a storage capacity that is a multiple of 4 bits.

22 is a shift control circuit, which controls left shift or right shift;
In other words, it controls clockwise or counterclockwise.

0, 1, 2, 3 are output boats, these output boats 0
, 1, 2, and 3 output pulses as shown in Fig. 6 d, a, c, and b whose phase is shifted by 90 degrees, respectively.

These output ports 0, 1, 2, 3 are connected to drivers 23, 24,
25, 26, and the D phase, A phase, C phase, and B phase of the four-pole step motor 20 are connected in this order via buffers (not shown), respectively. The reason why this order is D, A, C, B instead of A, B, C, D is because each pulse is rearranged so that it is output to the adjacent phase sequentially with a phase shift of 90 degrees. . Next, the operation of the present invention will be explained with reference to the flowchart shown in FIG.

First, an initial value is input into the register 21.

In other words, if the rotation is in the positive direction, step "1" in FIG.
If the rotation is in the opposite direction, set "1001" as in step "1" in FIG. 5b. Then, this set value is output port 0, 1
, 2, and 3, drive the drivers 23, 24, 25, and 26 of each phase of the step motor 20, and excite the solenoids.

When the register 21 is to be rotated clockwise by a signal from the shift control circuit 22 after the elapse of time t in FIG. 6, it is shifted to the left, and when it is to be rotated counterclockwise, it is shifted to the right. Then,
In the same way as above, the solenoids of each phase are energized and the
It will be in a step-ro state. After that, if the register 21 is shifted 3 times and rotated step by step every time t, the total 1
/6 rotations and returns to the initial state. More specifically, in the case of forward rotation, the initial value "0011" of step "1" in FIG. 5a is set in the register 21.

Then, since 1 and 0 of the output port are "1", the D phase and A phase are excited and set. Next, the shift control circuit 22 instructs the register 21 to shift to the left. Then, as in step "D" of Figure 5a, "0110"
and shifts one digit to the left, so the D phase is demagnetized and the A and C phases are excited. Then, it will rotate clockwise by one step until it goes out of low. Similarly, register 21 is set to "1100".
” → “1001” and rotated one step at a time. Further, the initial state becomes “0011” and the rotation is thereafter clockwise.

Next, in the case of reverse rotation, the initial value "1001" of step "1" in FIG. 5b is set in the register 21.

Then, since output ports 3 and 0 are "1", the D phase and B phase are excited and set. Next, the shift control circuit 22 instructs the register 21 to shift to the right. Then, as in step "D" in FIG. 5b, the rotor is shifted one digit to the right to "1100" and the rotor rotates counterclockwise by one step. Thereafter, it shifts from "0110" to "0011", and then returns to the initial state "1001" and thereafter rotates in the counterclockwise direction. In the above embodiment, the register 21 has four
However, in the case of 4n bits (n=1, 2, . . . ), the same initial value may be set for each of the upper and lower four bits. In the above embodiment, the case of a 4-phase step motor was explained, but the same method can be applied to a 4n-phase step motor (n=1, 2, . . . ).

Since the present invention employs the method described above, it is possible to easily change the direction of the step motor between clockwise and counterclockwise directions, and only requires the addition of a simple circuit, making it easy to implement and provide at low cost.

In particular, the present invention has excellent effects when used in devices that use a step motor, such as a printer equipped with a tractor feed device.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional step motor drive circuit.
FIG. 2 is a waveform diagram of each part, FIG. 3 is a block diagram for realizing the driving method according to the present invention, and FIG. 4 is a flow chart.
FIGS. 5a and 5b are explanatory diagrams of the output ports of the register during forward rotation and reverse rotation, and FIGS. 6a, b, c, and d are output waveform diagrams of each phase. 11... Clock pulse input terminal, 12...
・Pulse number control signal input terminal, 13...AND gate, 14, 15...Flip-flop circuit, 20...Step motor, 21...Register, 22...
...Shift control circuit, 0, 1, 2, 3... Output port, 23, 24, 25, 26... Driver. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 4n (n
is a positive integer), set the first initial value in the bit register, shift the register sequentially in the first direction every time a clock pulse is input, read the output of this register to the output port, and read the output of this register to the output port. is sequentially added to each of the 4n phases, the setting of the register is changed to the second initial value, and the direction of rotation is reversed by changing the shift direction of the register to the second direction. Driving method. 2. A method for driving a step motor according to claim 1, wherein the pulses applied to each phase of the step motor are sequentially phase-shifted by 90 degrees.