JPS6168615A - Speed controller - Google Patents

Abstract

PURPOSE:To easily change a speed command to a motor by measuring a pulse width which is a speed command value input to the motor and converting the result into a digital value to obtain a speed command value. CONSTITUTION:The signal of a liquid agent control solenoid valve 3 which is outputted from a main controller 2 with the signal of a flow rate sensor 1 is sent to a motor controller 4. This motor controller 4 is composed of a 1-chip microcomputer and a peripheral circuit for power control, etc., and drives a motor pump 5. Then, the width of a liquid agent control solenoid is measured and the measured value is converted from digital to analog to judge the amount of liquid agent and calculates an optimum motor speed, thereby controlling the speed of the motor 5. Consequently, the main controller 2 performs only control over liquid agent to optimize the speed of the motor automatically, and software for it is reduced, thereby decreasing output ports.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to speed control of a motor, and particularly to a method of taking in a speed command value. More specifically, in an apparatus comprising an adjusting device for performing a predetermined work and adjusting the amount of work, and a motor for performing another work in connection with the aforementioned work, the Il! The present invention relates to a speed control device suitable for controlling an I adjustment device and a motor in association with each other.

[Background of the invention]

Conventional speed control methods for DC motors include feeding back the output of a speed generator attached to the motor shaft and comparing it with a command voltage value to control the speed, and using pulses from an encoder attached to the motor shaft and speed command pulses. Analog methods, such as a method of controlling speed by detecting the phase difference between the motor and the motor, have been mainly used, but with recent advances in digital semiconductor technology, digital methods have come into use. We have proposed a method for digitally controlling a plurality of motors in Japanese Patent Application No. 59-26057. In the case of the digital control method, the speed command value is a digital quantity, and this value and the signal from the encoder attached to the motor shaft are converted into digital quantities and are compared for control. There is no problem if the speed is determined in advance and no consideration has been given to the method of giving the speed, but if the speed is commanded externally, the disadvantage is that a digital control device is required as the command device. There was.

An example of conventional use is shown in FIG. This device is an example of a device that mixes a chemical solution and water. In order to keep the concentration of the chemical liquid constant, the amount of mixed liquid used is detected by a flow rate center, and the amount of chemical liquid and water that is commensurate with the amount used is determined. The amount of chemical liquid can be controlled by changing the pulse width output to the solenoid valve for controlling chemical liquid. In other words, when the amount of chemical liquid is large, the pulse width is widened. On the other hand, when the amount of chemical liquid is large, it is necessary to increase the motor speed and water supply amount in order to keep the concentration constant.The main controller calculates the motor speed command and sends 8 to 12 bit data to the motor controller for control. ing.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed control device that can easily command the speed of motors used for different jobs.

[Summary of the invention]

The present invention accepts a pulse as a speed command value input to a motor, and by measuring this pulse width, converts it into a digital quantity and uses it as a speed command value, thereby making it possible to easily change the speed command. It is.

[Embodiments of the invention]

An example is shown in FIG. 1.The motor controller 4 receives the signal of the chemical liquid control solenoid valve 3 which is output from the main controller 2 in response to the signal of the flow rate sensor 1.The motor controller 4 mainly consists of a 1-chip microcomputer. It is composed of peripheral circuits such as power control, etc., and is configured to drive the motor pump 5. The chemical solenoid valve signal is connected to the input terminal of the aforementioned microcomputer. FIG. 3 shows a flowchart of the software of the microcomputer. In FIG. 3, SCF is a flag for confirming that the chemical liquid control solenoid SC has changed from L level to H level. Also, CNT is RA for measuring the width of SC.
M and DA are RAMs that store speed commands.In order to measure the width of 6SC, it is necessary to measure from the rising edge of the SC signal, so when the SC signal is at L level, 5CF = 1 and measurement does not start. Skip the routine.

If the SC signal is at H level and the last time this routine was run, the SC signal is at L level, measurement starts, and SC
Measurement is stopped when the signal becomes L level, and the measured value is moved to DA. At this time, CNT is set to 0 in preparation for the next measurement, and at the same time, 5CF=O is set. Since the measured value DA is proportional to the width of the SC pulse, the amount of chemical liquid at that time can be determined, and the microcomputer calculates the optimum motor speed for that amount of chemical liquid, making it possible to control the speed of the motor.

bawl. In addition, various D
It is also possible to store a group of speed command values corresponding to the values in A and select a speed command value from the group of speed command values.

Note that the width of the SC can be measured by an external measurement start command. Further, the SC signal is not the solenoid valve signal itself for controlling the chemical liquid, but it is also possible to create it by a method such as multiplying it by n based on that signal.

According to the present invention, if the main controller only controls the chemical solution, the speed of the motor will automatically become the optimum value, so the software of the main controller can be reduced, and the number of output ports can also be significantly reduced.

〔Effect of the invention〕

Generally, when changing the speed of the motor, changes in the amount of chemical liquid due to changes in the state and operating conditions of other equipment, such as changes in the flow rate as shown in the example above, and changes in flow rate due to changes in temperature and humidity are generally required. In many cases, there are other factors that require the speed to be changed. Nowadays, when equipment is controlled digitally, these other factors are often controlled by pulse width, and this method, which can measure this pulse width and automatically optimize the motor speed, uses the software and hardware of the main controller. The above effect is very large.

In the above embodiment, the speed command is given to the motor by the Ia device or the main controller of the device, but the motor is controlled by the main controller, and the device is controlled by this main controller. The same is true even if

Further, the technical idea of the present invention can be similarly implemented between multiple devices.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram showing one embodiment of the present invention, and FIG.
The figures are the same (conventional block diagram), and FIG. 3 is a diagram showing the main part of a flowchart of an embodiment of the present invention. 1...Flow rate sensor, 2...Main controller,
3... Solenoid valve for chemical liquid control, 4... Motor controller, 5... Motor pump.

Claims (1)

[Claims] 1. A control device that controls the rotational speed of a motor shaft using a pulse signal from an encoder attached to the motor shaft, in which the speed command value is given as a digital quantity, A speed control device characterized in that a width is measured inside the control device and converted into a digital speed command value. 2. A speed control device according to claim 1, characterized in that a control pulse for a controlled device is used as a speed command value pulse for a motor.