JP2727329B2 - Control method for electric blinds - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method for an electric blind or an electric shutter for raising and lowering a slat curtain by a motor. And a control method for driving or stopping the motor.

<Prior art> Conventionally, a stop mechanism in a device for raising and lowering a slat curtain typified by an electric blind or an electric shutter (hereinafter referred to as a slat elevating device) is provided by upper and lower limit switches or a photo interrupter or the like. The sensor detects the end of the upward movement and the end of the downward movement of the slat curtain, respectively. However, these detection methods inevitably increase the number of parts and increase the cost for wiring and adjustment work.

Therefore, efforts have been made to appropriately drive and stop the motor without using limit switches and sensors. FIG. 3 shows an emergency stop when the slat curtain is raised and lowered only by detecting the current of the motor of the slat lifting device.
Alternatively, a stop is performed at the upper and lower ends, which is disclosed in Japanese Patent Application No. 63-147855 filed earlier by the present applicant. Referring to FIG.
Current signal which is the absolute value of the motor current detected by
As for V1, only the AC component whose amplitude is centered on the amplitude reference level VN is extracted by the coupling capacitor 2 and the amplitude biasing resistor 3 which are current change detecting means. The extracted signal of the AC component is smoothed by a resistor 4 and a capacitor 5 as a smoothing means, and becomes a signal V5 indicating a change amount of the average current.
11 and the comparing means 12 respectively. The comparison means 11
When the input signal representing the variation of the average current exceeds a preset level a, a stop signal V6 for stopping the motor is transmitted, and the comparing means 12 outputs a signal representing the variation of the input average current. The motor is configured to send a stop signal V7 for stopping the motor when the level falls below a predetermined level b. If the variation of the average value of the motor current is within a predetermined level, the operation is continued. Conversely, when the motor departs from the predetermined level range, control is performed to stop the motor immediately.

According to the above control, when the slat curtain hits some obstacles when ascending or descending, or when the slat curtain is raised or lowered with respect to the upper end or lower end, even if the load of the motor changes suddenly A state in which the motor current changes abruptly is detected. As a result, it is possible to control the driving and stopping of the slat elevating device only by detecting the motor current.

<Problem to be Solved by the Invention> Although the above-described control method almost satisfied the initial purpose in the control relating to the stop of the motor of the slat elevating device, on the other hand, the steady operation due to the generation of the rush current at the time of starting the motor. In the process up to, a sharp current change occurs,
Although this is a normal operation process, this is regarded as a load change of the motor, and a stop signal is sent to stop the motor. This will be described with reference to FIG. FIG. 4 shows signal waveforms at various points in FIG. 3. Assuming that the motor is started at t0 and the slat curtain starts to rise or fall, the current signal V1 sent by the current detecting means is a rush current. And then settles to a steady state. Therefore, when this change is extracted and smoothed, a signal as shown in FIG. V5 is obtained. In other words, at the moment of activation, the amplitude is greatly shifted to the positive side with respect to the amplitude reference level VN
When the motor shifts to the steady state, it swings to the negative side because the motor current decreases. When the motor current reaches a steady state and a stable current is maintained, the current converges on the amplitude reference level VN with a time constant determined by the coupling capacitor 2, the bias resistor 3, and the resistor 4 and the capacitor 5. However, the comparison means 11 and 12 only perform a comparison with a predetermined level, and determine whether the change in the motor current is due to the start or the external force acting on the slat curtain. Can not. In order to solve this, in synchronization with the motor drive command, the time required for the motor current to settle and for the signal V5 representing the variation of the average current to converge on the amplitude reference level VN is determined by the comparison means 11 and 12. Is configured not to send a stop signal or to ignore the stop signal even if it is sent. Therefore, the time from the transition of the starting current to the steady state immediately after the start of the motor until the signal V5 representing the amount of change in the average current converges on the amplitude reference level VN, that is, the time T2 shown in FIG. In the width section, even if an external force acts on the slat curtain or the like and the motor should be stopped, the motor cannot be stopped by detecting this.

In addition, the time t1 in FIG. 4 indicates the case where the slat curtain hits an obstacle during the descent or the descent ends, and the current signal V1 sharply decreases and the signal V5 indicating the amount of change in the average current. Indicates a state of swinging to the negative side. Along with this, the stop signal V7 is transmitted in the section T4.
In FIG. 4, for convenience of explanation, the stop signal V6 or V7
Irrespective of the current signal
5 shows changes in V1 and a signal V5 representing the amount of change in the average current.

Usually, uneven rotation of the slat curtain winding drum,
In order to reduce the influence of the fluctuation of the mechanical loss of the winding and rewinding power transmission mechanism on the load fluctuation of the motor, for example, it is necessary to increase the time constant of the resistor 4 and the capacitor 5 in FIG. In addition, if it is intended to detect a change in the motor load due to a combination of a change in the actual winding diameter due to the diameter of the winding drum and the thickness of the wound material, and a change in the weight of the slat curtain due to winding and rewinding, the coupling may be used. It is necessary to increase the time constant of the capacitor 2 and the bias resistor 3, all of which result in prolonging the convergence time of the variation of the average current.

As described above, when starting the motor, the external force acting on the slat curtain or the like cannot be detected, so that the basic function of detecting an obstacle is temporarily impaired. Therefore, it is an object to minimize the time width during which the external force cannot be detected.

<Means for Solving the Problems> According to the present invention, the slat curtain is driven up or down based on a drive or stop signal, and the stop of the motor is determined based on the amount of change in the average current of the motor during the up / down drive. In a control method of a slat elevating device such as an electric blind, a current change amount detecting means for detecting a change amount of a current of the motor; a smoothing means for smoothing a change amount of a current obtained by the current change amount detecting means; First comparing means for sending a stop signal A when a signal representing the change amount of the average current obtained by the smoothing means exceeds a preset level a, and stopping when a signal falls below a preset level b; Second comparing means for transmitting the signal B; means for suppressing the level of the smoothing means when the stop signal A is transmitted; Means for supplementing the level of the smoothing means.

<Operation> Charge or discharge is performed in such a manner as to obstruct a change in the voltage level of the smoothing means for smoothing the amount of change in the current, in response to a stop signal sent from the comparing means connected to the subsequent stage. In this way, overcharging and overdischarging of the smoothing means are prevented, and an attempt is made to quickly respond to the next current change.

<Example> The operation of the present invention will be described based on an example.

In FIG. 1, a current signal V1 which is an absolute value of a motor current detected by a current detecting means 1 is composed of only an AC component by a coupling capacitor 2 which is a means for detecting a current change and a resistance 3 for amplitude bias, that is, Only the amount of change is taken out as a signal having the amplitude reference level VN as the center of the amplitude, and is smoothed by the resistor 4 and the capacitor 5 as the smoothing means to become a signal V2 representing the amount of change in the average current. The comparison means as the amplified signal
Sent to 11 and 12, respectively. The comparing means 11 sends a stop signal V3 for stopping the motor when the magnitude of the input signal V2 exceeds a preset level a.
Conversely, 12 sends a stop signal V4 for stopping the motor when the magnitude of the input signal V2 falls below a preset level b.

The stop signal V3 sent from the comparison means 11 is the signal V3
If the signal is sent at a logic high, the signal is inverted by the inverter 10 and the resistor 9 and the diode 6 suppress at least the level of the signal representing the variation of the average current, thereby absorbing at least a part of the signal. It works so as not to greatly exceed a. The diode 6 is connected to the resistor 9 from the inverter 10.
To prevent the capacitor 5 from being charged. If the inverter 10 has an open collector output stage, the diode 6 is unnecessary. The stop signal V4 sent from the comparing means 12 is, if the signal V4 is sent at a logic HIGH, directly lowering the level of the signal representing the variation of the average current via the resistor 8 and the diode 7. In order to suppress this, replenishment is performed so that at least the level b does not fall significantly below. Incidentally, the diode 7 prevents the suction operation from being performed when the stop signal V4 is not sent from the comparing means 12.

When the above operation is performed, each signal waveform in FIG. 1 becomes as shown in FIG. In FIG. 2, if there is the same change in the motor current as in FIG. 4, the current signal V1 sent by the current detecting means 1 has the same waveform as that in FIG. First, when the motor starts and a large inrush current flows through the motor, a large current change occurs in the rising direction.Therefore, the signal V2 representing the change amount of the average current tries to greatly increase with respect to the amplitude reference level VN. A stop signal V3 is sent from the comparing means 11 which should stop the motor after reaching the preset level a. In order to suppress this rise via the inverter 10, the resistor 9, and the diode 6,
As a result, the amplitude of the signal V2 is limited without greatly deviating from the level a.

Next, when the motor is settled to the steady operation current after the inrush current flows, since the motor current greatly decreases and the current changes in the descending direction, the signal V2 representing the average current change amount is based on the amplitude reference. The comparison means 12 sends a stop signal V4 in order to stop the motor at a predetermined level "b", in order to greatly lower the level VN.
Since this drop is suppressed via the resistor 8 and the diode 7, as a result, the amplitude of the signal V2 is limited without largely deviating from the level b. As described above, the signal V2 representing the amount of change in the average current is suppressed to a signal that does not greatly exceed the amplitude width determined by the levels a and b with respect to the amplitude reference level VN.

In the above embodiment, in order to suppress the signal V2 representing the amount of change in the average current, the form of sucking into the circuit ground potential and supplementing from the power supply voltage potential is adopted. The function of the present invention is impaired even if it is configured in the form of sucking and supplementing from another potential controlled by stop signals V3 and V4 sent from 11, 12 or sucking and supplementing with a constant current. It is easy to guess. Also, the stop signals V3, V4 transmitted by the comparing means 11, 12
Is different from the above embodiment,
If the signal V2 indicating the amount of change in the average current is suppressed on the + side with respect to the amplitude reference level VN, the signal V2 may be sucked in;

<Effects of the Invention> According to the present invention, when the signal V2 representing the amount of change in the average current deviates from a preset level, the amplitude of the signal is suppressed. The current change at the time of the change is quickly settled, and the preparation time for the next change is set to the second time from the time width of T2 shown in FIG.
The time is reduced to T1 shown in the figure. Therefore, when the stop signals V3 and V4 are ignored in the section from the occurrence of the rush current at the time of starting the motor to the steady operation, the time width to be ignored can be reduced to a minute time.

In the present invention, the amplitude of the signal representing the amount of change in the average current is suppressed by the stop signal sent once.
Detection of a change in the load of the motor during normal operation is not impaired. This is because the signal indicating the amount of change in the average current has no effect unless a state in which the motor should be stopped due to a load change is not detected. If necessary, a stop signal holding function may be added after the portion relating to the present invention to stop the motor even if the continuation of the stop signal sent from both comparing means is impaired by the amplitude suppression action. The function to be done is not impaired.

Further, the suppression of the amplitude of the signal indicating the amount of change in the average current can be realized, for example, simply by a zener diode. However, in the zener diode, since the threshold level of the comparison means can be only one-to-one, the threshold level is slat. If the zener diode is changed according to the type of the lifting device, the zener diode also needs to be changed. If the threshold level itself is delicate, it is difficult and requires a great deal of labor to select the zener voltage of the zener diode. In the present invention, since the amplitude suppression is determined in conjunction with the threshold level of the comparing means, the above problem cannot occur.

Therefore, according to the present invention, when the stop control of the slat lifting / lowering device represented by the electric blind or the shutter is performed by detecting the current of the motor, it is necessary to reduce the influence of the motor starting current to a very short time that is practically acceptable. Therefore, the reliability of the stop control is greatly improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a timing chart showing signal waveforms in FIG. 1, FIG. 3 is a circuit diagram showing a conventional example, and FIG. 3 is a timing chart showing signal waveforms of FIG. 13 …… OR circuit.

Claims (1)

(57) [Claims] 1. A control method for an electric blind or the like which raises or lowers a slat curtain based on a drive or stop signal and determines whether to stop the motor based on a change amount of an average current of the motor during the raising and lowering drive. A current change detecting means for detecting a change in the current of the motor, a smoothing means for smoothing a change in the current obtained by the current change detecting means, and a change in an average current obtained by the smoothing means. A first comparing means for sending a stop signal A when the signal representing the quantity exceeds a preset level a, and a second comparing means for sending a stop signal B when the signal falls below a preset level b. Means for suppressing the level of the smoothing means when the stop signal A is transmitted;
Means for replenishing the level of the smoothing means when the stop signal B is transmitted.