JPH0145320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stepping motor step-out detection method, and is particularly applicable to intermittent step-out detection, such as when a step motor during continuous step driving instantaneously stops responding to a control pulse. This invention relates to a method for detecting an abnormal state in a mode.

By applying a control pulse to the drive circuit, a step motor can control the amount of rotation proportional to the control pulse, and can easily control minute displacements, so it is useful, for example, for controlling the movement of printing paper in the line direction. It is used in printer devices as a driving source. In printer equipment, power supply voltage, ambient temperature,
Alternatively, mechanical friction, etc. may vary during operation or for each device, and setting the drive system of the step motor in response to these variable factors will reduce the size of the step motor and drive circuit, and the associated heat generation and power consumption. This leads to an increase in the capacity of the supply source, leading to an increase in the size of the printer device. To solve this problem, the step motor and its drive system were simplified.
The device shown in FIG. 1 has been adopted as one that takes measures to prevent synchronization. That is, printing paper 1
is sandwiched between a platen 2 and a pressure roller 3, a gear 5 fixed to a shaft 4 of the platen 2, a gear 6 meshed with the gear 5, and a stepping motor 7 whose shaft is directly connected to the gear 6. A driving system is used in which the stepping motor 7 receives control pulses from a pulse control circuit 8 for rotational displacement, and also for displacement from a slit disk 9 disposed at the other end of the driving shaft of the stepping motor 7. The signal is received by the slit sensor 10, and the displacement signal is fed back to the pulse control circuit 8 to form a closed loop control system, thereby making it possible to improve the response characteristics of the stepping motor and prevent synchronization. However, although the device shown in Figure 1 is certainly intended to prevent synchronization, the drive system absorbs fluctuations in the load on the stepping motor, such as drive control in the row direction of printing paper. As mentioned above, completely preventing step-out and miniaturizing the device are contradictory. Therefore, when considering application to printer devices that aim for miniaturization, it is necessary to completely prevent step-out due to instantaneous load fluctuations. It is best to detect the accompanying step-out condition and deal with it. In view of the various points mentioned above, the present invention is capable of sufficient step driving for normal loads, detects a step-out state when the load increases instantaneously, and displays or warns that abnormal driving has occurred. The purpose is to, and for that purpose,
Supplies power to the drive winding of the stepping motor, and
A pulse control means that sends control pulses that change the power supply state in a stepwise manner and also generates a sampling signal every time a predetermined number of control pulses are sent, and a pulse control means that is directly connected to the drive shaft of the stepping motor and that generates a A speed-to-voltage converting means for generating voltage, and time-integrating the output voltage from the speed-to-voltage converting means over a period corresponding to a predetermined number of pulses from the pulse control means, and making the output voltage correspond to the predetermined number of pulses. a charging/discharging means for periodically discharging; a level detecting means for detecting that the predetermined number of pulses has been applied to the charging/discharging means by comparing it with its own reference voltage; a delay means which receives a sampling signal generated at a period corresponding to the number of pulses and generates a delayed output; and a step-out detection circuit which receives signals from the level detection means and the delay means and outputs an AND signal thereof. The present invention provides a stepping motor step-out detection method comprising means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In Fig. 2, 7a is a stepping motor;
11 is a motor drive circuit, 12 is a pulse control circuit,
13 is a speed-voltage converter, 14 is a charging/discharging circuit, 1
5 is a level detection circuit, 16 is a differentiation circuit, 17 is an inversion circuit, 18 is a delay circuit, 19 is a step-out detector, 2
0 is a step-out memory indicator, and 21 is an alarm. Assume that a start signal is now input to the pulse control circuit 12 in the above configuration. As a result, the pulse control circuit 12 applies control pulses for forward or reverse rotation to the stepping motor 7a through the motor drive circuit 11. And stepping motor 7
a is a speed-to-voltage converter 1 directly connected to the drive shaft;
3 to transmit the step-like rotational speed. The speed-to-voltage converter is generally called a tachogenerator, and a power generation type that generates a voltage proportional to the rotational angular velocity is used in this example. 13 output signals are respectively represented by a and b in FIG. The output signal of the speed-to-voltage converter 13 is input to the charging/discharging circuit 14 at the next stage. In the charging/discharging circuit 14, the time constant during discharging is selected to be relatively much larger than the time constant during charging, and each time a predetermined number of pulses generated from the pulse control circuit 12 is generated, sampling pulses generated periodically by
Or, it has a built-in functional circuit that rapidly discharges the charge accumulated in the charging circuit in response to either the reset pulse generated during the initial state when power is supplied to the pulse control circuit, and its output The signal is represented in Figure 3c. Further, the output signal of the charge/discharge circuit 14 is input to a level detection circuit 15 connected to the next stage. The level detection circuit 15 is
An output voltage from the speed-to-voltage converter 13 corresponding to the number of control pulses that is one pulse less than the predetermined number of control pulses given from the pulse control circuit 12, and an output from the speed-to-voltage converter 13 corresponding to the predetermined number of control pulses. The reference voltage TL is set to be around the intermediate value of the voltage, and when the input signal applied from the charging/discharging circuit 14 in the previous stage is compared with the reference voltage TL and a predetermined number of control pulses are applied, the The output signal shown in Figure 3d is generated. The output signal of the level detection circuit 15 is input to a differentiating circuit 16 and an inverting circuit 17, respectively. The output signal of the inverting circuit 17 provides one input signal of the step-out detector 19, and is represented by e in FIG. Further, the other input signal of the step-out detector 19 is supplied to the pulse control circuit 12.
A sampling pulse generated synchronously every time a predetermined number of control pulses for driving the rotation of the stepping motor 7a is generated from the delay circuit 1.
9 and is later inputted, and is represented by f in FIG. In this way, a logical product is obtained as an output signal by each input to the step-out detector 19, and the output signal is represented by g in FIG. The waveforms a to g in FIG. 3 represent the stepping motor 7a.
is operating normally and there is no step-out, so every predetermined number of control pulses (in Figure 3, the number of control pulses shows an example in which a sampling pulse is given every 4 pulses). The output signal from the step-out detector 19 has a logical value of "0". Further, the output signal from the level detection circuit 15 mentioned above is given to the differentiating circuit 16, and the output signal of the differentiating circuit 16 is applied to the charging/discharging circuit 14 to accumulate the signal at a period corresponding to the predetermined number of pulses mentioned above. The charge is rapidly discharged in synchronization with the falling edge of the output signal indicated by d in FIG.

FIG. 4 shows waveforms at various parts when the stepping motor according to the present invention shown in FIG. 2 momentarily steps out. As can be seen from the figure, the step response stops at the third control pulse, and the output signal of the charge/discharge circuit 14 cannot reach the reference voltage TL of the level detection circuit 15 when the fourth control pulse arrives, causing the level detection As shown by the output signal d of the circuit 15, an output signal having a logic value of "0" appears. Therefore, the input signal to the step-out detector 19 is e,
The logical product output signal has a logical value of "1" as shown by f, indicating that the out-of-step state has been detected by the out-of-step detector 19. Then, the step-out memory display 20 connected to the next stage memorizes and displays the fact that the step-out has occurred, or sends an alarm signal indicated by h in the figure to the next-stage alarm 21 to sound an alarm. to occur.

As explained above, according to the present invention, an instantaneous load equivalent to within just a few pulses can be applied to a stepping motor in devices such as printers that require miniaturization, low cost, and power saving. By accurately identifying the phenomenon of intermittent step-out only when It is possible to minimize the size of the power supply and the like with respect to the load, and various beneficial effects such as low cost can be achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a conventional device showing a stepping motor for driving printing paper in the row direction in a printer device and its peripheral circuit. FIG. 2 is a circuit diagram employing the stepping motor step-out detection method according to the present invention. FIGS. 3 and 4 show signal waveforms at various locations on the stepping motor stepout detection circuit of the present invention shown in FIG. 2 during normal operation and as shown in FIG. 2 during abnormal step-out. FIG. 3 is a diagram showing signal waveforms at various locations on the circuit.

Claims (1)

[Claims] 1. A pulse control means 12 that supplies power to the drive winding of the stepping motor 7a and sends out control pulses that change the power supply state in a stepwise manner, and also generates a sampling pulse every time a predetermined number of control pulses are sent out; a delay means 18 that receives a sampling signal generated at a period corresponding to a predetermined number of pulses from the pulse control means 12 and generates a delayed output; a detection means that detects and outputs the rotational state of the stepping motor; In a stepping motor step-out detection method in which signals from the detection means and the delay means 18 are compared to determine step-out, a voltage proportional to the rotational speed is directly connected to the drive shaft of the stepping motor 7a. The generated speed-voltage conversion means 13 and the output voltage from the speed-voltage conversion means 13 are time-integrated in a period corresponding to a predetermined number of pulses from the pulse control means 12, and the output voltage is made to correspond to the predetermined number of pulses. a charging/discharging means 14 for discharging the battery at a certain period; a level detecting means 15 for detecting that the predetermined number of pulses has been applied to the charging/discharging means 14 by comparing it with its own reference voltage; 15 and a step-out detection means 19 which receives signals from the delay means 18 and outputs an AND signal thereof.