Photoelectric Switch Has A Good Hysteresis

Photoelectric switch definition: This product to light source for the media, the application of photoelectric effect, when the light source by the object shield or reflection, radiation and shading lead to changes in the amount of light to detect the object's presence, size and brightness, and to produce contact and no Contact output signal of the switching element. The photoelectric switch includes several types, which do not have the light source itself, and is detected by the change amount of the light emitted by the measured object. The illumination of the photoelectric switch by the natural light shields the amount of the change of the natural light from the object; the photoelectric switch itself has the light source, Of the light source to be detected by the object reflection, absorption, and transmission of light to detect the amount of change. Commonly used light source for the ultraviolet light, visible light, infrared light band, light source type bulb, LED, laser tube; output signal switch or analog and communication data information.

Photoelectric switch (photoelectric sensor) is the abbreviation of the photoelectric proximity switch, it is the use of objects to detect the beam or reflection, by the synchronous loop gating circuit, so as to detect the presence of objects. Objects are not limited to metal, and all objects that reflect light can be detected. The photoelectric switch converts the input current into the optical signal on the transmitter, and the receiver detects the intensity of the received light or the presence or absence of the target object. Most of the photoelectric switch is selected near the wavelength of visible light infrared light wave.

Photoelectric switch is composed of transmitter, receiver and detection circuit composed of three parts. The emitter is aimed at the target beam, and the emitted beam is typically derived from a semiconductor light source, a light emitting diode (LED), a laser diode, and an infrared emitting diode. The beam is continuously transmitted, or the pulse width is changed. The radiation intensity of the pulsed modulated beam is selected several times during the launch and runs unobstructed towards the target. Receiver has a photodiode or photoelectric transistor, composed of photovoltaic cells. In front of the receiver, there are optical elements such as lenses and iris. Behind it is the detection circuit, which filters out the effective signal and applies the signal. In addition, the structural components of the photoelectric switch also have a transmitting plate and an optical fiber. Triangular reflector is a solid structure of the launch device. It consists of very small triangular pyramidal reflective material, which makes it possible to accurately return the beam from the reflector. It can change the firing angle in the range of the optical axes 0 to 25 so that the beam is almost returned from an emission line, after reflection, or from the reflection line.

Photoelectric switches generally have good hysteresis characteristics, so that even if the object is shaking in a small range will not affect the output of the drive state, which can be maintained in a stable working area. At the same time, the self-diagnosis system can also display the light-receiving state and stabilize the work area to monitor the work of the photoelectric switch at any time.

Photoelectric switch working principle

Infrared is an electromagnetic ray, its characteristic is equivalent to radio or X-ray. The visible light is 380nm-780nm, the emission wavelength of 780nm-1mm long rays called infrared, infrared photoelectric switch is preferred to use near the wavelength of visible light near infrared.