JPS6348199A - Driving device for stepping motor - Google Patents

Abstract

PURPOSE:To generate no positional shift of a rotor due to the OFF/ON of a power source and position the rotor exactly, by setting exciting phase excited when the power source is recast, to be exciting phase excited when the power source is OFF and on the stop of the rotor. CONSTITUTION:The CW pulse or CCW pulse of output generated from a pulse generation circuit 2 is directed to an UP/DOWN counter circuit 4 for input, and the number of pulse is counted. The count value of the UP/DOWN counter circuit 4 is battery-backed-up, and the memory is retained, also when a power source is OFF. When the power source is re-cast after it is OFF, then the output of the pulse of a number equal to a step number found from the count value of the counter circuit 4 is directed to a driving circuit 3. As a result, excitation from an excitation step excited when the power source is OFF can be executed.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a driving device for a stepping motor. [Prior Art and Problems] [Prior art and problems] In a stepping motor, the stator windings are excited to the same state at every fixed rotation angle. There is a stable point for each rotation angle, and the path from stable point to stable point is divided into a fixed number of steps depending on the excitation method.

(Normally, there is a stable point every 7.2 degrees! 1) In the case of l-2 phase excitation, it is divided into 8 steps, and in the case of 5 phase excitation, it is divided into 10 steps. ) If the excitation phase that is the stable point is taken as the reference phase, then when the power is turned on to the drive device, excitation is always performed from the reference phase. Therefore, if the power is turned off and then turned on again without adjusting the drive output to the reference phase, the rotor of the stepping motor is forcibly drawn to a stable point where it is excited because it is excited from the reference phase. As a result, the position of the rotor when the power is turned on again is shifted from the position when the power is turned off, which poses a problem. For example, in the case of 1-2 phase excitation shown in the table below, the rotor position is at step 0 (reference phase) when the power is turned on, advances one step for each input pulse, steps 7, and then step O.
Return to When the power is turned off and then turned on again in a state other than step 0, the rotor is always drawn to the excitation position of the reference phase of step 0.

The position of the rotor when the power is turned off (the number of steps is 9).The rotation direction is either returned or advanced.

(○ indicates that it is excited) (Purpose of the invention) The present invention was made to solve the above problem, and the purpose of the present invention is to calculate the number of pulses output to the drive circuit when the power is turned off. To provide a stepping motor drive device that prevents the rotor from shifting when the power is turned OFF and ON by determining the excitation step that was excited and energizing the excitation step that was excited when the power was turned off when the power is turned on again. be.

(Summary of the Invention) The present invention is a stepping motor drive device in which stator windings are excited to the same state at every fixed step, and 8. A function to step the excitation phase according to input pulses and to turn off the excitation current. B. A pulse generation circuit that generates a set number of pulses and outputs them to the drive circuit; C. A counter circuit that counts the number of pulses output from the pulse generation circuit; D. When the power is turned off. A command signal for calculating the number of steps from step 0 (reference phase) for the excitation phase of the stepping motor in , based on the count value of the counter circuit, and turning off the excitation current i to the drive circuit before the drive power is turned on again. , outputs a number of pulses equal to the number of steps determined from the count value of the counter circuit to the drive circuit after the power is turned on, and then turns off the excitation current OFF command output output to the drive circuit. The present invention is characterized by comprising a control circuit having the following, and preventing the rotor from shifting when the power is turned on again.

(Embodiment of the Invention) An embodiment of the invention (in the case of 1-2 phase excitation) will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of a stepping motor drive device according to the present invention. In the figure, when a CW start signal is input from the control circuit 1 through the entire wire j2 or a CCW start signal through the entire wire 13 is input to the pulse generation circuit 2, the pulse generation circuit 2 receives a signal from the pulse number setting circuit 5 through the data bus 11. The CW pulse or CCW halus is generated according to the number entered in
Alternatively, it is input to the drive circuit 3 through the electric wire 8.16'. The CW pulse or CCW pulse output from the pulse generating circuit 2 is also input to the up/down counter circuit 4, and the number of pulses is counted. The count value of the up/down counter circuit 4 is backed up by a battery so that the memory is retained even when the power is turned off.

The processing order, mainly the operation of the control circuit 1 when the power is turned on again, will be explained using the flowchart shown in FIG. In the same figure, processing steps XX are indicated by 5XFF. When the main power is turned on again at 81.01, S
], at 02, an excitation current OFF command signal is output to the drive circuit 3 through the entire wire I7, and at 8103, a count prohibition command signal is output to the abup down counter 4 through the wire 18, and then at 8104, the stepping motor drive device is injected. After the drive power is turned on, at 8105, the count value
is read through. The absolute value of the value X read in step 8106 is divided by 8, which is the number of steps from the stable point to the stable point of the stepping motor, to obtain the integer value IXI of the quotient. Next, find the value x21 by multiplying this value ■X1 by 8,
The value X subtracted from the absolute value of this x21 read value 1 x 1
I'm looking for 3.

This value X3 indicates the excitation step of the stepping motor at the time when the power is cut off. 81.07 determines whether X3 is zero or not, and if x3 = Q, the excitation phase is in a stable state, so the pulse output for correction is not performed, and it is determined whether the read value X of 5113 etc. is positive or negative, and X is positive. If 5109'
& execute the CW correction pulse through the wires 9 and +5',
If is negative, S11.0k is executed and a CCW correction pulse is output to the drive circuit 3 through the electric wire 10116.

The drive circuit 3 advances the excitation phase from step 0 (reference phase) by the number of input pulses, but the rotor of the stepping motor does not rotate because the excitation current is turned off. 5
At 111, the control circuit 1 calculates the value X4 by subtracting 1 from X3 every time one pulse is output to the drive circuit, and at 5112 determines whether the subtracted value X4 has become O, and if it is not 0, it returns 8 again.
108 and subsequent steps are executed, and when the pulse becomes 0, the pulse output for correction to the drive circuit 3 is terminated. 8113 when the correction is completed
The excitation current OFF command output outputted to the drive circuit 3 is turned off at 5114, the count prohibition signal outputted to the up/down counter circuit is turned off at 5114, and the output is input from the pulse generation circuit 2 to the drive circuit 3 at 5115. A normal state is reached in which the rotor of the stepping motor 6 rotates according to the pulses.

(Effects of the Invention) As explained above, according to the stepping motor drive device of the present invention, the excitation phase that is excited when the power is turned on again is the excitation phase that was excited when the power was turned off and the rotor is stopped. Therefore, the rotor does not shift when the power is turned off and on, so accurate positioning can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the stepping motor drive device of the present invention. FIG. 2 is a flowchart for explaining the operation of the stepping motor drive device of the present invention when the power is turned on again.

Claims (1)

[Scope of Claims] A stepping motor drive device in which stator windings are excited to the same state at every fixed step, A. having a function of stepping the excitation phase according to an input pulse and a function of turning off the excitation current. A drive circuit; B a pulse generation circuit that generates a set number of pulses and outputs them to the drive circuit; C a counter circuit that counts the number of pulses output from the pulse generation circuit; D a control circuit for the stepping motor when the power is turned off. Calculating the number of steps from step 0 (reference phase) for the excitation phase based on the count value of the counter circuit, and outputting a command signal to the drive circuit to turn off the excitation current before the drive power is turned on again; It has a function of outputting a number of pulses equal to the number of steps determined from the count value of the counter circuit to the drive circuit after the drive power source is turned on, and then turning off the excitation current OFF command output output to the drive circuit. A stepping motor drive device comprising a control circuit and the following, and is characterized in that it prevents a rotor from shifting when the power is turned on again.