JPS5889085A - Motor control circuit - Google Patents

Abstract

PURPOSE:To control a plurality of driving mechanisms of different specifications by one controller by switching, controlling the speed of and the positioning of a controlling circuit of a motor with a small-sized computer. CONSTITUTION:An operation command from an operation unit 1 is inputted to a microcomputer 2. The microcomputer 2 controls the operations of a positioning controlling amplifier 4, a speed controller 5, a position detector 6, a limit switch 7, a resetting circuit 8, an emergency stopping circuit 9, an overcurrent protecting circuit 10, and a position detector 11 through an interface 3, and calculates or controls the output of switching, speed or alternating command of a control system, tachometer generator 55 and a current detector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit system for controlling a motor of a drive device for ultrasonic flaw detection.

Circuits for controlling the speed and positioning of the motor are generally known.

The present invention is for controlling motors of drive mechanisms of different specifications used in ultrasonic flaw detection and the like. That is,
A single control device is designed to control multiple drive mechanisms with different specifications. Note that the drive mechanism controls one unit at a time, and the drive mechanism is replaced at the end of the cable. Therefore, it is possible to accommodate differences in specifications such as motor capacity and speed generator, and differences in control methods.

The present invention uses a small electronic computer (microcomputer) to switch the motor control circuit and perform speed control and positioning control. In addition, since the motor capacities differ, the set current value of the overcurrent protection circuit is changed, the speed generator specifications are changed, and the position detector is changed (potentiometer, rotary encoder, etc.).
This is to switch one control circuit to various motors and control methods.

An embodiment of the invention is shown in FIG. Reference numeral 1 indicates an operation unit for operating the device, and 2 indicates an electronic computer, which may be a small device such as a microcomputer. 3 is an interface that controls the microcomputer and servo system. 4 is an amplifier section for positioning control. 5 is a motor speed control circuit. 6 is determined by the position detection section. 7 is the upper limit of the operating range of the drive mechanism section;
This is a limit switch installed at the lower limit. When this is activated, the motor will stop. 8 is a reset circuit. 9
is an emergency stop circuit. 1o is a motor overcurrent protection circuit. Reference numerals 4, 5, and 6 are analog servo systems that perform one positioning control.

Reference numeral 1 denotes an operation section from which operation commands are input to the microcomputer 2. The microcomputer 2 is connected via the interface 3.
Performs calculations and controls for switching control systems (positioning control, speed control), switching speed generator ranges, switching current detectors, and outputting speed or position commands. Further, in the case of digital positioning control, the value of a rotary encoder or the like is taken from the position detection circuit 11 and a position command is output to the D/A converter 35.

3 is an interface section between the microcomputer and the servo system. A decoder 31 decodes the code output from the microcomputer and identifies that the interface circuit has been selected.

The digital output circuit DO 32 is a signal for opening and closing an analog switch. It still outputs reset signals, etc. The interrupt input circuit PI 34 notifies the microcomputer that the servo system limit switch or overcurrent protection circuit has activated. 35 is a digital-to-analog converter D/A, which outputs speed commands and position commands to the servo system.

4.5.6 is an analog servo system and performs one positioning control. Further, by switching the analog switch 361 to the A side, only 50 circuits operate, and a speed control system is configured. In positioning control, when the analog switch 361 is set to B, a control system using an analog position detector such as a potentiometer is configured as a position detector. Also, when the 361 analog switch is set to the A side, D/
The A converter is connected to the speed control circuit. 6 position detectors
The configuration of the positioning control system using digital type such as rotary encoder 2 is as follows: microcomputer 2, D/A 35, speed control system 5, detector 62, detection circuit (counter etc.) 11
A digital positioning control system is constructed. A position command is input from the operation unit, a position signal from the position detection circuit 11 is read by a microcomputer, a deviation from the command is calculated, multiplied by a coefficient, and output as a speed command to a D/A converter.

v a = K (self = lower 7 vR,: speed command, K: proportional constant, PB: position command, P
F: Detected position Positioning control can be performed by applying the above VR as a speed command to the speed control circuit 5.

The speed control system No. 5 includes an amplifier 51, a relay 92, a current detection resistor 53, and a DC servo motor 54. It is composed of a speed generator 55, analog switches 363 to 365, resistors 57 to 59, and an amplifier 56. The relay 92 is for cutting off the motor circuit, and is used for emergency stop and stop due to the operation of limit switches 71 and 72. A resistor 53 is a resistor for detecting overcurrent. The speed generator 55 is for detecting the speed of the motor. In many cases, the output voltage value v/rpm per rotational speed of the speed generator differs depending on the drive mechanism. For this reason, the analog switches 363 to 365,
This is corrected by five resistors 57 to 5 and an amplifier 56. That is, the microcomputer can select one of the analog switches 363 to 365 depending on the output value of the speed generator. The microcomputer outputs preprogrammed contents to the digital output circuit 32 by a connected drive mechanism, and one of 363 to 36 and 5 is selected according to the bit information.

Resistors 57 to 59 are calculated resistors 56, which are selected according to the output value of the speed generator used.

The overcurrent protection circuit 10 protects the armature current of the motor.

It is detected by the resistor 53 and amplifier 101. amplifier 101
This is a first-order lag circuit, and the starting current of the motor,
The instantaneous current exceeding the rated current is smoothed by a stop current, etc., so that the overcurrent protection circuit does not operate.The amplifier 102 is used to detect when the motor is rotating in the opposite direction.105 is a voltage comparator.

Analog switches 366-36.8. Resistance I O7~
At step 110, the reference value of the voltage comparator is set to a value higher than the rated current of the motor. The analog switch selects the motor to be used, and is determined by the drive mechanism that is preprogrammed and connected to the microcomputer.

In a control device that controls multiple drive devices with one control device, when only one drive device is used at the same time,
One control circuit can be switched and used by a program.

Each drive device has differences in motor capacity, rated voltage, and current, differences in the output voltage value per rotation speed of the speed generator, and changes in overcurrent protection circuit setting values.1 Control systems such as positioning control and speed control. In the case of positioning control, there are differences between analog positioning control and digital positioning control systems, which make it possible to program the control system into an electronic computer and change the control system and various setting values to suit the drive device being used. I'll go.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1. A control device for controlling a servo motor, which includes an electronic computer, a digital-to-analog converter, a positioning control amplifier, a speed control amplifier, a speed generator, and an analog position detector. In the control circuit, a position command and a speed command are given from an electronic computer to an eleventh width generator via a digital-to-analog converter, and positioning control and speed control are switched from the electronic computer to an analog switch. A motor control circuit characterized by being able to configure a control system suitable for a drive device by switching a speed detection resistor according to the output voltage/rotation speed using an analog switch from an electronic computer. 2. In the claims, a resistor that detects the armature current of the motor, an amplifier that amplifies the voltage drop value of this resistor, a first-order delay circuit of the amplifier, a value corresponding to the motor rated current (-! There are multiple setting circuits that set the value to a value higher than or equal to , a circuit that switches this from an electronic computer using an analog switch, and a circuit that compares this setting value with the output voltage of the amplifier.
A motor control circuit that stops a motor when an overcurrent occurs in the motor, and is characterized in that an overcurrent setting value can be changed in response to a change in motor capacity. 3. In claims 1, 2, and 3,
Equipped with a digital position detector and a digital position detection circuit, the digital position detection circuit is read by a digital computer, the deviation between the position command and the detected value is calculated, and the result is multiplied by a coefficient (or multiplied by the coefficient in Kanto) to convert digital to analog. A device that outputs a speed command to a converter, operates an analog speed control system, and performs digital positioning control. Multiple drive devices can be controlled by one control device, and the control system can be switched by a computer program. A motor control circuit featuring: