Classification and characteristics of photoelectric switches

The photoelectric switch (photoelectric sensor) is the abbreviation of the photoelectric proximity switch. It utilizes the shielding or reflection of the light beam by the detected object, and the gate circuit of the synchronous loop is used to detect the presence or absence of the object. Objects are not limited to metals, all objects that can reflect light can be detected. The photoelectric switch converts the input current into a light signal on the transmitter, and then the receiver detects the target object according to the intensity or presence of the received light. The common photoelectric switch smoke alarm in the security system is often used in the industry to count the number of movements of the mechanical arm.

1 According to the detection method

Commonly used photoelectric switch classification method: According to the detection method, it can be divided into three types: reflection type, through-beam type and specular reflection type. The through-beam detection is far away from the slot-type photoelectric switch and can detect the density (transmittance) of translucent objects. The reflective working distance is limited near the intersection of the beams to avoid background effects. The mirror reflection type has a longer reflection distance, which is suitable for long-distance detection, and can also detect transparent or semi-transparent objects.

2 Classified by structure

According to the structure, the photoelectric switch can be divided into three types: the amplifier separated type, the amplifier built-in type and the power supply built-in type. The amplifier separation type is to separate the amplifier and the sensor, and is made with a dedicated integrated circuit and a mixed installation process. Because the sensor has the characteristics of ultra-small and multi-variety, the amplifier has more functions. Therefore, this type adopts the terminal block connection method, and can be used for both AC and DC power supplies. It has the function of on and off delay, can set the light and sound switch, can control 6 kinds of output states, and the photoelectric switch has two output modes: contact and level. The built-in amplifier is an integrated amplifier and sensor, made with ASIC and surface mounting technology, and works with a DC power supply. Its response speed situation (there are two kinds of 0.1ms and 1ms), can detect small and high-speed moving objects. Changing the polarity of the power supply can switch between bright and dark movement, and can set a self-diagnostic stable work area indicator. Both voltage and current output modes can prevent mutual interference, which is very convenient in system installation.

The built-in power supply unit integrates the amplifier, sensor and power supply device, and is made with a dedicated integrated circuit and surface mount technology. It generally uses AC power and is suitable for replacing contact type limit switches at the production site, and can be directly used for strong current control circuits. You can also set self-diagnostic stable work area indicator lights by yourself. The output is equipped with SSR solid state relay or relay normally open and normally closed contacts, which can prevent mutual interference and can be installed in the system closely.

Features of photoelectric switch

The MGK series photoelectric switch is the product of the development of modern microelectronics technology, and is an upgraded product of the HGK series infrared photoelectric switch. Compared with the previous photoelectric switches, it has its own remarkable characteristics:

●With self-diagnosis and stable working area indication function, it can promptly tell the radio-type photoelectric switch whether the working status is reliable or not;

●The through-beam, reflective, and mirror-reflective photoelectric switches all have the function of preventing mutual interference and are easy to install;

●The setting of ES external synchronization (external diagnosis) control terminal can pre-check whether the photoelectric switch is working normally before running. It can accept interruption or detection instructions from computer or programmable controller at any time. The proper combination of external diagnosis and self-diagnosis can make the photoelectric switch intelligent;

●Fast response speed, the response speed of the high-speed photoelectric switch can reach 0.1ms, 300,000 detection operations can be performed per minute, and small objects moving at high speed can be detected;

●Using ASIC and advanced SMT surface mounting technology, it has high reliability;

●Small size (minimum only 20×31×12mm), light weight, simple installation and debugging, and has a short-circuit protection function.