JPS58100763A - Ultrasonic wave switch - Google Patents

Abstract

PURPOSE:To reduce malfunction and to improve detection precision by stopping the output of a receiving circuit when the time width of a received signal is longer than set time. CONSTITUTION:A transmitting circuit 2 consists of an integration circuit 7, monostable multivibrator 8, oscillating circuit 9, and amplifying circuit 10, and transmits an ultrasonic wave of frequency equal to the oscillation frequency of the oscillating circuit 9 from a transmitting oscillator 1. A receiving circuit 4 consists of an amplifier 11, turning and amplifying circuit 12, detecting circuit 13, gate circuit 14, comparator 15, switching circuit 16, and time comparing circuit 6. The time comparing circuit 6 compares the time width of an output with set time and then inhibits the output of the receiving circuit 4 from being supplied to the switching circuit 16 when the time width of the output is longer than the set time width.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a transmitting transducer that is driven by the output of a transmitting circuit and emits ultrasonic waves, a delivery transducer that receives ultrasonic waves reflected from a detection target, and In an ultrasonic switch having a receiving circuit that processes a signal and drives a relay,
This relates to an ultrasonic switch characterized in that a time comparison circuit is provided in the wave reception circuit, and the output of the wave reception circuit is stopped when the time of the handover signal is longer than the set time of the time comparison circuit. .

The purpose of the present invention is to quickly determine whether the received signal is a regular reflected ultrasonic wave or foreign noise based on the shape of the signal received by the receiving transducer, and to quickly operate the relay. The goal is to make it possible.

Conventional ultrasonic switches do not determine whether the signal received by the receiving transducer is a regular reflected ultrasonic wave or an external ultrasonic wave. The relay was operated as shown in Figure (b) only when the received signal was received several times in a row. Therefore, it is not possible to quickly determine whether or not it is an external noise, and it is not until the relay operates as shown in Figure 1 (b).
This method has the drawback that it takes time T1 to process and cannot be acted upon immediately.

The present invention has been made in view of this point, and will be explained in detail in the following embodiments.

In Fig. 2, (1) the transmitter oscillator, the transmitter circuit (2
)'s output is driven to emit ultrasonic waves. (3) is a delivery transducer, which receives the ultrasonic waves emitted from the transmitting transducer (1) and reflected from the object to be detected.It converts the received ultrasonic waves into electrical signals, and converts them into electrical signals. 4) to operate the relay (fi). A feature of the present invention is that a time comparison circuit (6) is provided in the delivery circuit (4). The transmitter circuit (2) consists of an integrator circuit (7), a monostable multivibrator (8), an oscillator circuit (9), and an amplification circuit (10), and is configured to adjust the oscillation frequency of the oscillation (b) path (9). Equal ultrasonic waves are emitted from the transmitting transducer +11. The wave receiving circuit (4) consists of an amplifying circuit (12+, a detecting circuit), which receives one wave and tunes to the frequency of the next ultrasonic wave.
It is composed of a gate circuit (14), a comparator O@, a switching circuit end, and a time comparison circuit (6), which amplifies and detects the transfer signal, and outputs a If it is in the time of the gate circuit, which is a regate, the comparator (I61) compares the level, the output is compared in time with the time comparison circuit (6), and is input to the switch: / gate circuit. The time comparator circuit (6) is driven by the rising edge of the output of the comparator O@, and outputs an output during a slightly longer period of time than the transmission signal.

Now, when an ultrasonic wave like 1 @ 3 axis) is emitted from the transmitting transducer +11, the gate circuit (14) is shown in Figure 3 (b).
outputs a signal like this, and while this output is present, the detection circuit C
When there is an output of I'4, this output is connected to a comparator (l@
Enter. In period T of FIG. 3(b), the gate circuit O is set up as follows in order to cut the direct loop from the transmitting transducer +1) to the receiving transducer (3). The received ultrasonic signal reflected by the object to be detected and received by the receiving transducer (3) is amplified and detected, and the level is compared by a comparator. Output is output from comparator a as shown below. This output has approximately the same magnitude during the transmitted signal and during time. The time comparator circuit (6) is driven by the rising voltage vK of this output, as shown in Fig. 3(d).
Outputs a constant periodic output such as . Funparator 06
) is shorter than the time width set in the time comparison circuit (6), the normal reflected ultrasound is received and determined to be 9, the switching circuit Oφ is operated and the relay (5 ) is driven and operated as shown in Fig. 3(e).

When external noise is received, the time is more than 10 times that of regular reflected ultrasound, so even if the level is higher than the level of the fushiparator (E), the time comparison circuit (
6), the switching circuit (1
61, the output of the wave receiving circuit (4) is output, and the relay (6) does not operate.

As shown above, in the present invention, a time comparison circuit is provided in the reception circuit, and the output of the reception circuit is stopped when the time of the reception signal is longer than the set time of the time comparison circuit. Because it determines whether the received signal is a regular reflected ultrasound or external noise based on the shape of the signal received by the sensor, the determination can be made quickly, the relay can be operated quickly, and there are fewer malfunctions. This has the effect of improving detection accuracy.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are time charts of a conventional ultrasonic switch, Figure 2 is a block circuit diagram of an embodiment of the present invention, and Figures 3 (a) to (e) are time charts of the same. It is a chart. 111... Wave transmission vibrator, (2)... Wave transmission circuit, (3
)...Receiving oscillator, (4)...Delivery circuit, (6)...
・Relay) (6)...Time comparison circuit. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] ft) A transmitting transducer that is driven by the output of the transmitting circuit and emits ultrasonic waves, a receiving transducer that receives the ultrasonic waves reflected from the object to be detected, and a receiving transducer that processes the received signals and drives a relay. In an ultrasonic switch having a wave receiving circuit,
An ultrasonic switch characterized in that a time comparison circuit is provided in the wave reception circuit, and the output of the wave reception circuit is stopped when the time of the reception signal is longer than the set time of the time comparison circuit.