JPH0261579A - Driver for ultrasonic sensor - Google Patents

Abstract

PURPOSE:To prevent malfunctioning in the setting of a plurality of sensors by generating a transmission pulse signal with a half-wave rectification signal as synchronous signal. CONSTITUTION:An earth side discriminator section 2 applies a specified alternating current to a half-wave rectification section 3 discriminating the earth side of a commerical AC power source to form a synchronous signal with a half- wave rectification of the AC power source and a transmitter section 4 generates a transmission pulse signal by the synchronous signal. Then, a transmission/ reception switching section 5 applies a transmission pulse to an ultrasonic sensor 7 when the transmission pulse signal is generated and a reception pulse signal from the sensor 7 is applied to the receiving section 6 between transmission pulses. Here, the receiving section 6 measures a time difference between the transmission pulse and a reception pulse and when the time difference is below a specified value, a relay circuit 6c is turned ON to activate an automatic door operator. In this manner, an interval of generating the transmission pulses ranges from 18 to 20 milliseconds to secure a propagation time of the sensor 7 set at an upper part of an automatic door thereby preventing a malfunctioning otherwise caused by reception of a pulse by one sensor from the other.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a drive device for an ultrasonic sensor that detects the presence or absence of an object by transmitting and receiving ultrasonic waves.

<Prior Art> Automatic door opening/closing devices and the like use ultrasonic sensors to detect the presence or absence of objects such as humans. This type of ultrasonic sensor driving device includes means for generating a transmission pulse signal that causes the sensor to send out ultrasonic pulses, and turning on and off a relay according to the time difference between the transmission pulse signal and the reception pulse signal from the sensor. and means for switching between transmission and reception of the sensor. Then, the automatic door is opened and closed by turning the switch on and off.

When performing wide-area detection, multiple ultrasonic sensors each connected to the above-mentioned drive device must be arranged, but conventional drive devices do not have a means to synchronize the transmission pulse signals of each drive device. It wasn't. Therefore, ultrasonic pulses are sent out separately from each sensor.

(Problems to be Solved by the Invention) In conventional drive devices, when a plurality of ultrasonic sensors are arranged as described above, one sensor receives an ultrasonic pulse sent from another sensor, There is a problem in that malfunctions occur because the time difference between the transmitted pulse signal and the received pulse signal is short, such as when an object is detected.

(Means for Solving the Problems) The present invention is an ultrasonic sensor drive device proposed to solve the above problems, and includes means for determining the ground side of a commercial AC power source and switching the phase of the AC power source; means for half-wave rectification of the AC power supply connected to the phase switching means, and generating the transmission pulse signal using a half-wave rectified signal from the half-wave rectification means as a synchronization signal. It is.

According to the above configuration, even when multiple ultrasonic sensors are installed and used, the transmission pulse signals generated by the drive device connected to each ultrasonic sensor are accurately synchronized, so that each ultrasonic sensor is The ultrasonic pulses from the sonic sensors are also precisely synchronized.

<Example> Hereinafter, one embodiment of the present invention will be described based on the drawings.

The figure is a block diagram of a drive device according to the present invention.
, a ground side discriminator 2, a half-wave rectifier 3, a transmitter 4,
It is composed of a transmission/reception switching section 5 and a receiving section 6.

The power supply section 1 steps down the AC voltage of a commercial AC power supply using a transformer la, and supplies driving power for the drive device using a power supply circuit 1b.

The grounding side discrimination section 2 discriminates the grounding side of the commercial AC power supply using the grounding side discrimination circuit 2a, and also switches the phase changeover switch 2b to determine the phase of the alternating current given to the half-wave rectification section 3 from the step-down commercial AC power supply. Let be a predetermined phase.

The half-wave rectifier 3 performs half-wave rectification on the stepped-down commercial AC power source using the half-wave rectifier circuit 3a, and provides the half-wave rectified signal as a synchronization signal to the transmitter 4.

The transmitter 4 is composed of a monostable multi-circuit 4a, an oscillation circuit 4b, and an amplifier circuit 4c connected in series, and a synchronizing signal from the half-wave rectifier 3 is applied to the monostable multi-circuit 4a. and generates a transmission pulse signal.

The transmission/reception switching unit 5 switches the transmission/reception of the ultrasonic sensor 7 using a transmission/reception switching circuit 5a, and when the above-mentioned transmission pulse signal is generated, it gives the transmission pulse signal to the ultrasonic sensor 7, and between each transmission pulse signal there is an ultrasonic wave. The received pulse signal from the sensor 7 is given to the receiving section 6.

The receiving section 6 includes an amplifier circuit 6a, a control circuit 6b, and a relay circuit 6c connected in series.
The time difference between the transmitted pulse signal and the received pulse signal of the transmitter 4 is measured, and when the time difference is less than a predetermined value, the relay circuit 6c is turned on to operate an automatic door opening/closing device or the like.

A commercial AC power supply (50 or 60H) that has been half-wave rectified as described above.
By using z) as a synchronization signal, the generation interval of the transmission pulse signal can be set to 18m5ec or 20ssec. Therefore, for example, 2 to 2.5 meters from the floor above the automatic door.
It is possible to secure the propagation time necessary for the ultrasonic sensor 7 installed at a height of .

Furthermore, even when a plurality of ultrasonic sensors 7 are installed and used, the transmission pulse signal generated by the drive device connected to each ultrasonic sensor 7 is processed by the ground side discriminator 2 and the half-wave rectifier 3. The ultrasonic pulses from each ultrasonic sensor 7 will also be accurately synchronized.

(Effects of the Invention) As described above, according to the drive device of the present invention, even when a plurality of ultrasonic sensors are installed and used, one sensor receives ultrasonic pulses sent from other sensors. This prevents malfunctions caused by such factors.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of the present invention. [...Power supply section, 2...Ground side discrimination section. 3...Half-wave rectifier section, 4...Transmission section. 5... Transmission/reception switching section. 6... Receiving section. 7... Ultrasonic sensor.

Claims (1)

[Claims] Means for generating a transmission pulse signal that causes an ultrasonic sensor that transmits and receives ultrasonic waves to send out an ultrasonic pulse, and a relay that operates according to a time difference between the transmission pulse signal and a reception pulse signal from the sensor A drive device comprising means for turning on and off, and means for switching transmission and reception of the sensor, comprising means for determining the ground side of a commercial AC power source and switching the phase of the AC power source, and a means connected to the phase switching means for switching the AC power source. 1. A driving device for an ultrasonic sensor, comprising means for half-wave rectifying a power source, and generating the transmission pulse signal using a half-wave rectified signal from the half-wave rectifying means as a synchronization signal.