The superiority of photoelectric sensor detection

The use of photoelectric sensors to detect advanced systems in automation equipment and devices is also the basis for advanced process control, operation optimization, and energy-saving strategies.

In this paper, through the statistical analysis of the photoelectric sensor circuit principle and test results, it has obtained more applicable, operational feasibility, and parameter optimal performance indicators, which created favorable conditions for on-site use.

1. Working principle The photoelectric sensor is a switch that emits a light source through infrared or invisible light. The chip receives the signal and makes a corresponding action to detect the presence or absence of an object within a certain distance, as shown in Figure 1.

1.1 The transmissive type is shown in Figure 2. Install the emitter and receiver face to face, adjust the position and sensitivity of the optical axis and connect the power supply; then adjust the emitter and receiver to the left and right, and fix the switch on the action indicator. Center position; adjust the position in the up and down direction according to the same method; after the adjustment is completed, place the detection object on the optical axis and fix it in a stable action position.

※ If the detection object is translucent or small (∮16mm or less), it may not be detected because the light can pass through;

※ For the sensitivity adjustment method, please refer to the setting and adjustment method of the diffuse reflection photoelectric switch.

1.2 Mirror emission type As shown in Figures 3 and 4, the mirror reflection type photoelectric sensor and reflector (MS-2) are placed face to face and then the power is turned on. Then, fine-tune the position of the reflector and photoelectric switch left and right, confirm the operating range of the action indicator, and fix it at the center position; adjust the up and down position in the same way; after the adjustment is completed, place the detection object on the optical axis, and It is fixed at the stable action position;

※ If two or more photoelectric switches are used at the same time in parallel, the distance between them should be greater than 30cm, leave enough space between the switch and the measured object, or place the measured object and the optical axis at an angle of 30-45 degrees, (close distance detection For objects with high emissivity, a photoelectric switch with a built-in polarizing mirror can be selected for use) ※ For the sensitivity adjustment method, please refer to the setting and adjustment method of the direct reflection photoelectric switch.

1.3 The reflection type of the polarizer is shown in Figure 5. When the light emitted by the illuminator passes through the polarizer, it will be changed into horizontal and transverse light and reach the mirror MS-2 (MS-3), and then it is caused by the mirror. It changes into a vertical light and reaches the polarizing mirror of the light receiver. This detection object can also be detected by a general mirror.

1.4 The diffuse reflection type is shown in Figures 6 and 7. Generally, it can be used at the maximum sensitivity position, but considering the influence of the background object and the installation surface, the sensitivity must be adjusted; the detection object is placed in the detection position, and the sensitivity adjustment knob Slowly adjust from the minimum sensitivity position (Min.) to the action indicator (yellow LED) ON and the self-diagnosis indicator (green LED) OFF position, record this position as; remove the detection object, continue to slowly increase the sensitivity knob to When the action indicator (yellow LED) is OFF and the self-diagnostic indicator (green LED) is ON, mark this position as. [When the self-diagnosis indicator (green LED) and action indicator (yellow LED) are both OFF, the maximum sensitivity (Max.) position is the position]; the middle position of the and is the best sensitivity position;

※ The above sensitivity adjustment method is based on the light incident action, the action indicator light (yellow LED) during the shading action is the opposite;

※ The detection distance recorded in the product specification is based on the size of white matte paper. The detection distance varies with the size of the detection object, the surface condition, and the presence or absence of gloss.

2. The application confirms the passage of objects in the narrow aisle, detects whether there is a transparent bottle, determines the shape of the accessory, detects the pin of the accessory, determines the presence or absence of the thread, determines the direction of the IC, detects the elevator position, detects whether the bottle falls, and the product is automatically transported Line and so on.

3. Parameter comparison Product model: BX series Features: timing mode selection, built-in timer, built-in voltage reverse connection protection, over-current protection (see Table 1)

※ (*1) Equipped with MS-4, the detection distance is the same, and it can detect within less than 0.1m;

※ (*2) With MS-2, the detection distance is 0.1-2m, and it can be detected within 0.1m;

※ (*3) Matte white paper (200mmX200mm).

4. Analysis and comparison

4.1 The detection distance of the photoelectric sensor has certain specifications;

4.2 The standard detection objects of through-beam type, specular reflection type, polarized reflection type and diffuse reflection type are different;

4.3 The hysteresis distance specification requirements of the through-beam type, specular reflection type, polarized reflection type, and diffuse reflection type are different;

4.4 The light sources of through-beam type, specular reflection type, polarized reflection type and diffuse reflection type are different;

4.5 The accessories and weights of the through-beam type, specular reflection type, polarized reflection type, and diffuse reflection type are different. 5. Conclusion The superior and advanced detection performance of photoelectric sensors, such as excellent protection, sensitivity and accuracy, is widely used in automatic equipment detection devices. However, it is still restricted by the conditions of use. It is strictly forbidden to use strong light, sunlight, spotlights, and direct incident photoelectric switches. Within the direction angle, it is necessary to use a shading plate, a support plate and other requirements for use.