JPH04134200U - Pulse motor step-out detection circuit - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide a pulse motor step-out detection circuit that can detect step-out in a short time with a relatively simple and small circuit configuration. [Configuration] A current detector that converts and detects the drive current flowing through the pulse motor into voltage, and a reference current generator that outputs a voltage corresponding to the reference drive current when the pulse motor is rotating normally. , a comparator that compares the output voltage of these current detectors with the output voltage of the reference current generator, and a controller that controls the pulse motor on and off according to the output signal of this comparator.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a pulse motor step-out detection circuit. This is related to period detection.

0002

[Conventional technology]

Generally, the torque obtained with a pulse motor varies depending on the frequency of the drive pulse. It is possible to increase the frequency of the drive pulse to make the pulse motor rotate faster. Therefore, the torque obtained becomes smaller. By the way, the torque required for a pulse motor is determined by the load applied to the pulse motor. Therefore, if the load changes, the required torque will also change. At this time, the pulse mode - If the load on the pulse motor becomes greater than the torque obtained from the motor, the pulse The motor no longer rotates normally in synchronization with the drive pulse, resulting in a loss of synchronization.

0003 This kind of step-out can occur, for example, when pulses are used as a drive source for the chart feed mechanism of a recording device. When using a motor, do not change the feed speed suddenly to a high speed, or prevent dust from entering the feed mechanism. This is likely to occur when the load increases due to adhesion of debris. When the motor loses synchronization, the back electromotive force inside the motor decreases and the drive current increases. There is a problem in that the peripheral circuits become overheated. According to a specific example, the drive current is about 600 mA in normal rotation state, but in a step-out state, The current was about 700mA.

0004 Therefore, in order to detect step-out, a photointerrupter as shown in Figure 3 is used. A new device is being considered. In Fig. 3, 1 is a pulse motor, and its output shaft A plate 3 is attached to 2. 4 is a photo interrupter, - light beam 3 is arranged in a positional relationship that allows the light beam to pass through the optical path. In such a configuration, the plate 3 guides the optical path of the photointerrupter 4 in a predetermined direction. Whether the pulse motor 1 is rotating normally or is out of step depending on whether it crosses the cycle or not. can be detected.

[0005]

[Problem that the idea aims to solve]

However, with this conventional configuration, there are many mechanical components and the device itself becomes difficult to use. The shape of the body becomes larger, and the time between when a step-out occurs and when it is actually detected increases. The problem is that it takes time.

[0006] This invention focuses on these problems, and its purpose is to solve relatively simple problems. We offer a pulse motor step-out detection circuit that can detect step-out in a short time with a compact circuit configuration. It is about providing.

[0007]

[Means to solve the problem]

The present invention that achieves these objectives is A current detector that converts and detects the drive current flowing through the pulse motor into voltage; Outputs a voltage corresponding to the reference drive current when the pulse motor is rotating normally. a reference current generator for A comparator that compares the output voltage of these current detectors and the output voltage of the reference current generator and, A controller that controls the pulse motor on and off according to the output signal of this comparator. La, It is characterized by being composed of.

[0008]

[Effect]

The comparator constantly monitors the drive current flowing to the pulse motor. and pulse Indicates that the motor has stepped out and has become larger than the standard drive current that flows under normal rotation. When detected, the output signal turns off the pulse motor drive.

[0009]

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention, and shows a chart feeding mechanism of a recording device. An example is shown. In the figure, 5 is a current detector, which flows to the pulse motor 1. The drive current i is converted into a voltage Iv, detected, and output to the integrator 6. The integrator 6 detects the overshoe included in the voltage signal applied from the current detector 5. The comparator uses smooth motor current data Idat to remove distortion and ringing. Output to one input terminal of 7. 8 is a reference current generator, which is used as a reference when pulse motor 1 is rotating normally. The other input terminal of the comparator 7 uses the voltage corresponding to the drive current as the reference current data Iint. Output to child. Comparator 7 outputs its output signal Icmp to controller 9. The controller 9 turns on the pulse motor 1 according to the output signal Icmp of the comparator 7. , outputs a control signal D for off-control to the motor driver 10. The motor driver 10 operates according to the control signal D applied from the controller 9. A pulse M for driving the pulse motor 1 is output. Here, the current detector 5, integrator 6, comparator 7 and reference current generator 8 are used to detect step-out. It constitutes the exit part.

0010 The operation of FIG. 1 will be explained. Comparator 7 receives motor current data output from current detector 5 via integrator 6. Compare Idat and the reference current data Iint output from the reference current generator 8, and then The signal Icmp is output to the controller 9 under the following conditions. When Iint ≧ Idat, Icmp = 1 (pulse motor: on) When Iint < Idat, Icmp = 0 (pulse motor: off) The controller 9 controls the motor according to the output signal Icmp applied from the comparator 7. A control signal D for driving the pulse motor 1 on and off is output to the driver 10. Ru. The motor driver 10 operates according to the control signal D applied from the controller 9. A drive pulse M is applied to the pulse motor 1 to feed the chart in the recording device.

[0011] Next, the step-out detection operation will be explained. FIG. 2 is a waveform diagram of the drive current flowing through the pulse motor 1. As shown in FIG. In addition, in Figure 2, Bar shoot and ringing are omitted. The solid line in Figure 2 indicates the pulse mode in normal conditions. The maximum value of this drive current is the rated value of pulse motor 1. or imax determined by the settings of the motor driver 10. On the other hand, the broken line in Figure 2 is the drive current when the pulse motor 1 loses synchronization, and its maximum The large value is id, which is larger than the maximum value imax in the normal state. Therefore, when the reference current data is set to imax, the drive current that actually flows through the pulse motor 1 is By comparing with current data, step-out of pulse motor 1 can be electrically confirmed in a short time. It is actually detectable.

0012 With this configuration, the drive current i of the pulse motor 1 can be constantly monitored. Step-out of pulse motor 1 can be quickly detected using the The rotation of the loose motor 1 can be turned off. Therefore, the time when overcurrent flows through the pulse motor 1 becomes extremely short, so the pulse The burden on the motor 1 is reduced, and overheating of peripheral circuits can be suppressed to a minimum. Furthermore, since such devices can be constructed using only electronic circuits, conventional mechanical equipment is not required. The mounting space is small compared to the It is also effective for downsizing.

[0013]

[Effect of the idea]

As explained above, according to the present invention, step-out can be achieved with a relatively simple and small circuit configuration. This makes it possible to realize a pulse motor step-out detection circuit that can detect motor out-of-step in a short period of time.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

2 is a waveform diagram of a drive current flowing through the pulse motor 1 of FIG. 1. FIG.

FIG. 3 is a configuration explanatory diagram showing an example of a conventional pulse motor step-out detection device.

[Explanation of symbols]

1 Pulse motor 5 Current detector 6 Integrator 7 Comparator 8 Reference current generator 9 Controller 10 Motor driver

Claims (1)

[Scope of utility model registration request] Claim 1: A current detector that converts and detects the drive current flowing through the pulse motor into voltage, and a reference current generator that outputs a voltage corresponding to the reference drive current when the pulse motor is rotating normally. A comparator that compares the output voltage of these current detectors with the output voltage of a reference current generator, and a controller that controls the pulse motor on and off according to the output signal of this comparator. A pulse motor step-out detection circuit characterized by: