JPH02193580A - Control device of motor rotation - Google Patents

Abstract

PURPOSE:To detect abnormality in a short time by changing a monitor value for detection of abnormality according to an objective rotation speed of a motor. CONSTITUTION:A motor rotation control device is composed of a key board 1, a micro-computer (micon) 2, a pulse distributer 3, a deflection counter 4, a D/A converter 5, etc., and controls rotation of a motor 6. The micon 2 is composed of a CPU 11, etc., and can read the number of stored pulses of the deflection counter 4. According to a set rotation speed, a monitor range of a count value of the deflection counter 4 is determined by a digital switch 8. Abnormality can be thereby detected in a short time while the rotation does not run away.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a motor rotation control device, and more particularly to a motor rotation control device capable of detecting an abnormality in a motor.

(Prior Art) Generally, when controlling a motor, so-called feedback control is performed based on the deviation between a target rotational speed and an actually detected rotational speed.

In a device that performs such control, one of the configurations for detecting abnormal rotation of the motor due to an abnormality in the motor or the device driven by the motor is to monitor the above deviation, and when the deviation exceeds a predetermined value, the motor rotation is stopped. There is a configuration that detects abnormalities.

In this configuration, the difference between the frequency of the command pulse corresponding to the target rotation speed and the frequency of the feedback pulse corresponding to the actual rotation speed is counted as a deviation, that is, the number of droop pulses.

If the counted number of droop pulses exceeds a predetermined number of monitoring pulses, it is determined that the rotation is abnormal.

By the way, for example, if the rotation of the motor stops due to some abnormality and the feedback pulse frequency becomes O,
When the number of monitoring pulses mentioned above is N, the time t until an abnormality is detected, that is, the time t until the deviation counter counts the frequency fcp of the command pulse and exceeds the number N of monitoring pulses, can be expressed as t=N/fcp. This relationship is shown in FIG.

[Problem to be solved by the invention]

However, in conventional devices, the number of monitoring pulses N was set to a fixed value, so as is clear from the above equation and Figure 4, the lower the frequency of the command pulse, the longer it takes to detect an abnormality. During this time, there was a risk that the motor would be irreparably damaged due to some kind of abnormality occurring in the motor or the like.

Also, since the motor rotates at a rotational speed proportional to the number of droop pulses on the deviation counter, if the number of monitoring pulses is set to a large value, for example the maximum rotational speed of the motor, the number of feedback pulses may become O due to an abnormality. When this occurs, the motor rotation becomes high speed, causing problems such as runaway motor rotation and other problems, such as aggravating motor abnormalities.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to change a monitoring value for abnormality detection according to the rotation speed set as the target rotation speed of the motor. It is an object of the present invention to provide a motor rotation control device capable of detecting an abnormality in a short period of time and before the rotation of the motor goes out of control.

[Means to solve the problem]

To this end, the present invention includes a setting means for setting the rotational speed of the motor, a command pulse generation means for generating pulses with a frequency corresponding to the rotational speed set by the setting means, and a feedback pulse with a frequency corresponding to the rotational speed of the motor. a deviation counter that counts the difference between the frequency of the command pulse and the frequency of the feedback pulse, a motor drive means that drives the motor based on the count value of the deviation counter, and the count value of the deviation counter. A count value monitoring means for determining whether or not the rotation speed is within a range determined according to the rotation speed set by the setting means, and an abnormality in which the count value monitoring means performs a predetermined process when it is determined that the count value is not within the range. It is characterized by comprising a processing means.

[Effect]

According to the above configuration, the monitoring range of the count value in the deviation counter is determined according to the set rotation speed.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a motor rotation control device showing one embodiment of the present invention. In the figure, 1 is a keyboard, which is used to input various settings related to motor drive, such as the target rotational speed of the motor and the amount of movement of a moving object driven by the motor. 8 is a digital switch, which will be described later. Enter the value to set the monitoring value range for the number of droop pulses. 2 is a microcomputer, which includes a CPU II that executes the processing procedure described later, a ROM 12 that stores the processing procedure etc. described later in FIG. 2, and a CPU I
It has a RAM 13 that is used as a work area for processing executed by I, and executes motor rotation control and processing detailed below. Reference numeral 3 denotes a pulse distributor in which data on the target rotational speed of the motor and the number of dispensing pulses related to the amount of rotation, that is, the amount of movement are set based on the control of the microcomputer 2; Based on these data, command pulses corresponding to the target rotational speed are generated, and a completion signal iR is output to the microcomputer 2 when the set number of pulses has been delivered.

4 is a deviation counter consisting of an up/down counter, and the frequency of the command pulse CP and the feedback pulse B described later are
The difference from the frequency of P is counted as the number of droop pulses (deviation), and this number of droop pulses is output. That is, the number of droop pulses increases when the command pulse frequency is larger than the feedback pulse frequency, and decreases when it is smaller.

5 is a D/A converter that converts the accumulated pulse number output from the deviation counter 4 into a p/A converter, 6 is a motor whose rotational speed etc. are controlled based on the analog output value from the D/A converter 5, and 7 is a motor. 6 is detected, and the rotation speed is determined by the feedback pulse B.
This is an incremental encoder that outputs the converted frequency of P.

In the above configuration, the microcomputer 2 can read the number of accumulated pulses from the deviation counter 4, and performs the motor abnormality detection process shown in FIG. 2 below.

FIG. 2 is a flowchart showing the processing procedure for motor abnormality detection control. First, in step 520, the accumulated buff Lz number is read from the deviation counter 4, and then in step 5
At step 21, it is determined whether or not this number of droop pulses is abnormal based on the command frequency fcp corresponding to the target rotational speed and the monitoring value range set by the digital switch 8. Unless an abnormality is detected here, the process returns to step 520 and the acquisition of the number of accumulated pulses is repeated.

If an abnormality is detected in step 521, a droop pulse clear signal CLR is output to the deviation counter 4 in step 522, and the present process ends. As a result, the number of accumulated pulses in the deviation counter 4 becomes "0", and as a result, the output of the D/A converter 5 also becomes "0", and the motor 6 stops.

The processing of steps 520 and 521 described above will be explained in detail below.

First, in step S2Q, the microcomputer 2
is the number of accumulated pulses N from the deviation counter 4 at a predetermined timing.
In step 521, it is checked whether the following formula is satisfied.

That is, for example, if the number of droop pulses No. when the motor 6 rotates at the rated rotation speed and the command pulse frequency fcpo at this time are the number N of droop pulses at the target rotation speed, the number N of droop pulses at the target rotation speed is generally the number of command pulses at the target speed. Using frequency, N = (fcp /fcpo) ·N.

This relationship is shown in FIG.

As a result, the monitoring range of the number of droop pulses can be determined by the target rotation speed set with the keyboard], that is, the command pulse frequency fcp at this time, and the monitoring value range set with the digital switch 8. Since the monitoring range can be determined according to the speed, it is possible to set the monitoring range narrowly.

Note that the monitoring of the number of droop pulses does not necessarily have to be performed using a range having an upper limit and a lower limit, and for example, only the upper limit may be used depending on the motor or the device driven by the motor.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the monitoring range of the count value in the deviation counter is determined according to the set rotational speed.

As a result, the monitoring range can be set in detail, abnormality can be detected in a short time when an abnormality occurs, and motor runaway can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a motor rotation control device according to an embodiment of the present invention, Fig. 2 is a flowchart of abnormality detection processing according to an embodiment of the present invention, and Fig. 3 shows the number of accumulated pulses and the number of command pulses. FIG. 4 is a diagram showing the relationship between the abnormality detection time and the command pulse frequency. 1...Keyboard, microcomputer, pulse distributor, deviation counter, D/A converter, motor, incremental encoder, digital switch, CPU. ROM. RAM.

Claims (1)

[Scope of Claims] 1) Setting means for setting the rotational speed of the motor; command pulse generation means for generating pulses with a frequency corresponding to the rotational speed set by the setting means; a feedback pulse generating means for generating a feedback pulse with a frequency of a given frequency; a deviation counter that counts a difference between the frequency of the command pulse and the frequency of the feedback pulse; and a motor that drives the motor based on the count value of the deviation counter. a driving means; a count monitoring means for determining whether the count value of the deviation counter is within a range determined according to the rotational speed set by the setting means; the count monitoring means; A rotation control device for a motor, comprising: abnormality processing means that performs predetermined processing when it is determined that the rotation is not within the range.