JPH0833398A - Rotation monitoring method of pulse motor - Google Patents

Abstract

PURPOSE:To obtain a rotation monitoring method in which the normality detection of the rotation of a pulse motor is realized by a low-cost means without using a costly rotation detection part. CONSTITUTION:A rotation monitoring method makes use of a situation that the voltage waveform at the end of an exciting coil and the current waveform of the exciting coil are different between the rotation and the nonrotation of a rotor for a pulse motor 3. An amplification part 5a, an amplification part 5b and an analog-to-digital conversion part 6 are provided. The normality of the rotation of the pulse motor is judged by using an operation expression which emphasizes the characteristic of different waveforms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring the correct rotation of a pulse motor widely used in general industrial fields.

[0002]

2. Description of the Related Art There are many devices and apparatuses that use a pulse motor. Here, while various methods are put into practical use, an indicator recorder (hereinafter referred to as a recorder for recording a measurement signal with a pen such as a temperature recorder) is used. , Abbreviated as a recorder), and the conventional example of FIG. 4 to which the present invention can be applied will be described. The measurement signal 21 is the control unit 2
The pulse is converted into a pulse for driving the pulse motor 23 by 2 and the motor is rotated, the recording unit 25 is moved via the belt 24, and recording is performed on the recording paper 26 that moves at a constant speed in the arrow direction. On the other hand, according to the pulse generated by the control unit, the pulse motor
The rotation detection unit 29 detects that the 23 has rotated, and the control unit 22
Then, the normal value was monitored by comparing the drive value with the rotation result.

FIG. 5 shows another conventional example, and points different from FIG. 4 will be described. A magnetic scale 31 whose position can be magnetically determined is provided near the belt 24, and the position sensor 3 integrated with the recording unit 25 is provided.
In step 2, the fact that the rotation of the pulse motor 23 is correctly transmitted to the recording portion is returned to the control portion 22.

[0004]

In this conventional example, a highly reliable magnetic sensor or encoder is used to detect the position of the recording portion and the rotation of the motor, but it is expensive, while the inexpensive potentiometer is used. Can not be used because of poor contact due to sliding. An object of the present invention is to realize a large cost reduction by omitting the expensive detecting section, and to provide at low cost various devices and apparatuses using a step motor.

[0005]

According to the monitoring method of the present invention, the values of the voltage and the current of the exciting coil for rotating the pulse motor stepwise are calculated by the formulas, and the set value corresponding to the calculated value is calculated. It is a method of determining whether the motor is rotated by comparing with. Further, according to the method of claim 2, an individual data memory for storing the characteristics of the pulse motor itself used is provided, and the values of the voltage and current of the exciting coil for rotating the pulse motor in steps are calculated by the formulas defined. This is a method of determining whether or not the motor has been rotated by comparing the calculated value with the set value of the individual data memory.

Further, according to the method of claim 3, if the calculated value obtained by dividing the voltage value of the exciting coil by the current value in the above two methods is a set value or more, rotation is performed, and if it is less than the set value, non-rotation is performed. It can also be judged. Furthermore,
According to the method of the fourth aspect, the voltage value and the current value of the exciting coil can be the arithmetic average values of a plurality of sampling values. Then, according to the method of claim 5, the pulse motor can drive the recording unit to a position corresponding to the measurement signal by the receiver.

[0007]

According to the method of the present invention, when the excitation coil for stepwise rotating the pulse motor does not rotate even if a voltage is applied, the waveforms of the voltage and current show the characteristics of an ordinary coil, and when the motor is rotating, Utilizing the fact that the back electromotive force is generated and the voltage / current waveform is disturbed, the voltage / current value of the exciting coil that rotates the pulse motor in steps is calculated, and the result is compared with the set value It can be determined whether the rotation is normal. According to the method of claim 2, the voltage and current values of the exciting coil for stepwise rotating the pulse motor are calculated, and the results are compared in advance with the measured and calculated individual motor characteristic set values. It is possible to determine whether the motor has normally rotated.

According to the method of claim 3, the arithmetic expressions in the above two methods can be used for the determination by dividing the voltage value of the exciting coil by the current value. Further, according to the method of claim 4, the voltage value / current value of the exciting coil is
Characteristic variations can be averaged as an arithmetic average value of a plurality of sampling values. In addition, according to the method of claim 5, it can be used for a rotation monitoring method of a pulse motor for positioning a recording unit in correspondence with a measurement signal by a receiver.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention is shown in FIG. 1, and the operating principle of a pulse motor will be briefly described with reference to FIG. 2 for better understanding. Although the embodiment shown in FIG. 1 is a two-pole motor, a three-pole motor will be described for simplicity. The poles 11 of the stator with the coil 12 face each other in the same phase. When a pulse is applied in the order of ACB, the rotor 13 rotates to the right due to the magnetic force of the stator, and when it is added in the order of ABC, it rotates to the left.

The voltage and current waveforms of one coil of this pulse motor are shown by the solid line in FIG. When a voltage is applied to the coil at time t ₀ , a current flows, the magnetic pole is magnetized, the rotor rotates by one step and stands still, and at time t ₁ no voltage is applied.
The current value does not simply increase and shows a concave shape, and the voltage value becomes halfway as shown in the figure because the counter electromotive force due to the rotation of the rotor is generated in the coil. If an abnormality occurs and the rotor does not rotate even if a pulse is received, a counter electromotive force does not occur, and therefore a dotted line characteristic of a normal coil is shown.

FIG. 1 is a circuit diagram of a main part of one exciting coil. The sensor output change control arithmetic unit 1 is not shown, the exciting coil 3 of the stepping motor 3
The pulse driver 2 is signaled to send one pulse to a. The output of this driver generates a voltage between it and the circuit potential _Vcc, and a current flows through the resistor 4 and the exciting coil 3a. Here, the voltage of the reference potential Vs provided separately from the output potential of the driver is amplified by the amplifying unit 5a, and the voltage of the resistor 4 is also amplified by the amplifying unit 5b and converted by the analog-digital converting unit 6 to control the arithmetic unit 1. Return to. The output of the amplifier 5a has the voltage value of FIG. 3, and the output voltage of the amplifier 5b is divided by the resistance value to obtain the current value of FIG.

[0012] In this configuration, for example, be determined in computing the characteristic ratio of the voltage value V _t and the current value i _t at time t by the solid line in FIG. 3, the rotation and many normal rotation also in consideration such as ambient temperature changes The range of the characteristic ratio of normal rotation is determined as the set value from the data without. Similarly, the differential value and the voltage value V _t and the current value i _t time t, may be determined integral value of the voltage and current values from time t ₀ to t ₁ to compare respectively. In addition to this, various calculations are conceivable. Among them, the normal rotation data is always normal, and the data when it does not rotate is always determined to be non-rotation. Calculate and judge with 1. Here, if the voltage application time is longer than the operation completion time of the rotor, the rotor may rotate at a low speed due to friction caused by dust and the like, and the voltage and current waveforms may exhibit characteristics close to the dotted line. The voltage application time considers the operation completion time of the rotor,
It is desirable to make it short.

The method of claim 2 can further include an individual data memory 7 in FIG. In consideration of variations in the characteristics of the pulse motors, this memory stores the set values obtained from the actual measurement data of the individually mounted pulse motors and uses them for judgment. Furthermore, claim an example of operations in three ways, the voltage value V _t of the current i _t in dividing the normal rotation if the calculated value is more than the set value of 3, is determined to a non-rotating if less than the set value. Further, in the method of claim 4,
Although only the time t is shown in the calculation of the characteristic in FIG. 3, it is also possible to make a judgment by using a plurality of arithmetic mean values of sampling values in a range that characterizes the difference between the waveforms of the solid line and the dotted line.
In addition, according to the method of claim 5, this method can be used for positioning drive of the recording portion of the recorder.

[0014]

According to the method of the present invention, since the normality of the rotation of the pulse motor is monitored based on the result of calculation and determination from the voltage / current waveform of the exciting coil of the pulse motor, the expensive rotation Since the detector is not required and the alternative is an inexpensive amplifier and analog-digital converter, an inexpensive and highly reliable pulse motor rotation monitoring method can be provided. Further, according to the method of claim 2, since the calculation data of the pulse motors used individually are used for the determination, an inexpensive and highly reliable rotation monitoring method of the pulse motors can be provided.

Further, according to the methods of claims 3 and 4, the voltage waveform of the exciting coil is divided by the current waveform for determination, and the voltage / current waveform is sampled and arithmetically averaged. Therefore, a highly reliable and inexpensive pulse motor rotation monitoring method can be provided. And claim 5
According to the above method, by using this rotation monitoring method of the pulse motor, a receiver using the pulse motor can be provided inexpensively and highly reliably.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment relating to one exciting coil of the present invention.

[Fig.2] Principle of rotation of step motor

FIG. 3 is a characteristic diagram of voltage and current in the circuit of the present invention.

FIG. 4 is a block diagram of a conventional embodiment.

FIG. 5 is a configuration diagram of another conventional example.

[Explanation of symbols]

1 Control Calculation Section 2 Pulse Driver 3 Pulse Motor 3a Excitation Coil 5a Amplification Section 6 Analog-to-Digital Conversion Section 7 Individual Data Memory

Claims (5)

[Claims] 1. A method of monitoring the rotation of a pulse motor, wherein the voltage and current values of an exciting coil for stepwise rotating the pulse motor are calculated by an equation, and the motor is rotated by comparison with a set value corresponding to the calculated value. A method for monitoring the rotation of a pulse motor, which comprises determining whether or not the rotation has been performed. 2. A pulse motor rotation monitoring method, comprising: an individual data memory for storing the characteristics of the pulse motor, wherein the voltage and current values of an exciting coil for rotating the pulse motor stepwise are calculated by an equation. A rotation monitoring method for a pulse motor, characterized in that the rotation of the motor is judged by comparing with the set value of the individual data memory corresponding to the calculated value. 3. The method according to claim 1, wherein if the calculated value obtained by dividing the voltage value of the exciting coil by the current value is greater than or equal to a set value, it is determined to be rotating, and if it is less than the set value, it is determined to be non-rotating. A method for monitoring the rotation of a pulse motor, which comprises: 4. The rotation monitoring method for a pulse motor according to claim 3, wherein the voltage value and the current value of the exciting coil are arithmetic average values of a plurality of sampling values. 5. The rotation of the pulse motor according to claim 1, wherein the pulse motor drives the recording unit to a position corresponding to the measurement signal in the receiver. Monitoring method.