Today, Wuxi Rihuan Sensing Technology Co., Ltd. will introduce to us how to handle multiple sets of photoelectric "conflicts"? Learn about "time stagger" and "separation".

On automated production lines, the scenario of multiple groups of photoelectric sensors being densely installed is becoming increasingly common. However, many on-site observations reveal that the more sensors are installed, the more malfunctions occur - when there is no object passing through, the equipment frequently stops; or when an object has already passed, the sensor does not respond. This is not due to a malfunction of the sensors, but rather they are "fighting" with each other.

I. Why do they "fight"?

The reflective photoelectric sensor consists of a light emitter (the transmitting end) and a light receiver (the receiving end). When multiple groups of reflective photoelectric sensors are installed in close proximity in several groups, the light emitted by the light emitter of group A may be received by the light receiver of group B. The receiver cannot distinguish whether this beam of light is from "its own home" or "that of its neighbor", thus causing a false action.

The same problem exists for reflective photoelectric sensors - when multiple units are installed in close proximity, a beam of light reflected may enter the receiver of an adjacent sensor. The more sensors and the denser the installation, the greater the probability of "fighting".

II. Solution 1: Cross-configuration ("Time-shift" layout)

The most effective way to prevent interference between multiple groups of reflective photoelectric sensors is to install the light emitter and receiver crosswise.

The specific approach is: install the light emitter and receiver of adjacent two groups of sensors in opposite directions - the light emitter of the first group is on the left and the receiver is on the right, and the light emitter of the second group is on the right and the receiver is on the left. In this way, the light emitted by the light emitter of group A is received by the receiver of group A, and the light emitted by the light emitter of group B is received by the receiver of group B, and there will be no "crossing" between them.

For three or more groups of sensors, in addition to cross-configuration, the group spacing should also be increased. The more groups, the larger the spacing should be.

III. Solution 2: Increase spacing (Physical isolation)

If cross-configuration is restricted by the site conditions, increasing the spacing is the most direct alternative solution. Different installation methods have different requirements for spacing:

When using reflective photoelectric switches in parallel, they must maintain a distance of more than 1.4 times the detection distance from each other.

When using reflective photoelectric switches in parallel, they must maintain a distance of more than 40% of the detection distance from each other.

The greater the detection distance, the larger the spacing should be. The specific spacing should be determined based on on-site debugging. The basic principle is: test each sensor one by one when powering on, confirm that the adjacent sensors do not interfere with each other, and then fix the installation position.

IV. Solution 3: Use different frequencies ("Time-shift" operation)

In addition to the "time-shift" in space, signal-level "time-shift" can also be achieved to prevent interference. Using different operating frequencies of devices is also an effective anti-interference method.

The principle is simple: different frequency light pulses are like different "languages" - the sensor of group A says "Chinese", and the sensor of group B says "English", they do not understand each other, and naturally will not respond falsely. Some high-end photoelectric sensors support multi-channel switching function, and adjacent sensors can be set to different channels to achieve parallel installation without interference.

In addition, by controlling the detection time slots of different photoelectric sensors, allowing adjacent sensors to stagger their detection periods, signal frequency mutual interference can also be avoided.

V. Other considerations

Strong light source interference: Avoid placing the light axis of the sensor directly facing strong light sources such as sunlight or incandescent lamps. When the angle cannot be changed, a shading plate or shading tube can be added above the sensor.

Cable isolation: High-voltage lines, power lines, and the cables of photoelectric sensors should not be placed in the same cable tray or conduit. Otherwise, it will cause false actions or damage due to induction. Signal lines and power lines must be routed in separate cable trays.

Installation stability: The transmitting end and the receiving end should not be installed at an angle, loose, and should be kept parallel. In vibration environments, anti-vibration brackets should be added.

Note: The above translations are based on the provided Chinese text and may not be 100% accurate. Summary

Solution Applicable Scenarios Core Points

Cross arrangement Parallel installation of multiple sets in opposite directions Projectors and receivers are arranged in reverse interlaced layout

Increase spacing Compact installation of reflective or interlocking type Reflective type ≥ 1.4 times detection distance; Interlocking type ≥ 40% detection distance

Different frequencies Space limitation, unable to increase spacing Select multi-channel models, set different frequencies for adjacent devices

Time slice staggered arrangement Compact installation of sensors of the same frequency Control detection period and work in staggered shifts

The conflict between photoelectric sensors is not a quality issue, but an installation method issue. Learn to "stagger" and "isolate" - cross arrangement, increase spacing, use different frequencies. Three steps will complete it, and multiple sets of sensors can coexist harmoniously without interfering with each other.

The photoelectric sensor series of Rihuan Sensing provides multi-channel anti-interference models, supports setting different working frequencies for adjacent devices, effectively avoiding mutual interference in dense installation. The product is suitable for various installation scenarios such as interlocking type, mirror reflection type, and diffuse reflection type. Welcome to follow Rihuan Sensing and obtain professional photoelectric detection solutions.