反射传感器的功能原理和技术
反射传感器属于光电传感器，适用于借助 LED 红光对物体进行非接触式识别，不受颜色、形状和表面特性的影响。反射传感器的功能原理基于一种检测方法，这种方法将能量原理和三角测量原理结合在一个传感器中。
三角测量原理:
三角测量原理是一种几何方法，用于确定物体的距离。在反射传感器中，传感器与参考背景之间的距离用作参考信号。
三角测量原理是一种几何方法，用于确定物体的距离。在反射传感器中，传感器与参考背景之间的距离用作参考信号。
能量原则：
在能量原理中，对接收到的信号强度进行分析。反射传感器使用在参考背景漫反射的 LED 红光的强度作为参考信号。
在能量原理中，对接收到的信号强度进行分析。反射传感器使用在参考背景漫反射的 LED 红光的强度作为参考信号。
反射传感器的功能原理
反射传感器利用与参考信号的偏差，即距离或光强度的变化来检测物体。传感器向静态或动态背景发送或发射光线，例如传送带。如果光束被一个物体截断，会触发传感器的切换过程。前提条件是，任何背景都处于传感器的探测范围内，因此无需使用反射器。
除了距离之外，反射传感器还能检测漫反射的光强度。这样可以实现检测，不受颜色或表面等物体特性的影响。
盲区与最小距离有什么区别？
盲区与要检测的物体有关。如果有物体处于盲区，无法进行可靠检测。相反，最小距离定义了作用范围的下限或参考背景的允许距离。最小距离表示背景与传感器之间的距离。如果参考背景与传感器距离太近，光线不再照射到接收元件上。因此无法将传感器正确示教到参考背景上。
反射传感器有盲区吗？
反射传感器没有盲区，因为除了距离之外，反射传感器还会考虑光强度相对于已示教参考背景的变化。因此，由于传感器接收到的光强度减弱，即使是位于光学系统正前方的物体也能检测到。但是，必须考虑到，如果一个与参考背景距离相同的物体，且具有相同的漫反射，则反射传感器不能识别。
P1PM 反射传感器示例：
参考背景的最小距离：在不锈钢上 100 mm…1,000 mm（100 mm 是背景与传感器之间的最小距离，但不是物体与传感器之间的最小距离）
盲区：由于采用两级探测原理，无盲区
参考背景的最小距离：在不锈钢上 100 mm…1,000 mm（100 mm 是背景与传感器之间的最小距离，但不是物体与传感器之间的最小距离）
盲区：由于采用两级探测原理，无盲区
反射传感器具有哪些示教模式？
Both operating modes can be set via IO-Link so that the sensors reliably detect objects against a static or moving background. This allows both modes to be tested in order to optimally adapt the sensor to the application. Setting two separate teach-in modes offers the advantage that extremely flexible and simple teach-in of reflex light barriers is possible. There is also the option of selecting a pre-set variant.
Teach-in to a Moving Reference Background
Possible Uses of Reflex Light Barriers for Object Detection
Presence check
Contrast recognition
Fill-level monitoring
Ejection control
The Following Must Be Observed when Installing Reflex Light Barriers
Background Colors
For reliable detection, there must be a clear contrast between the object and the taught-in reference background.
Tip: If there is a small difference in contrast, select a large distance between the object and the background!
Highly Glossy, Reflective and Uneven Backgrounds
In the case of highly reflective, glossy or uneven surfaces, it should be ensured that no direct reflections fall on the receiving optics, as they can impair object detection.
Tip: Place the sensor at a slightly tilted angle!
Steps, Edges and Recesses
To ensure reliable detection, the light spot must be aligned directly with the reference background.
Tip: Align the sensor to a specified background!
Moving Background
For moving reference backgrounds such as conveyor belts, the movement should be perpendicular to the transmitter/receiver axis of the sensor to avoid direct reflections on the receiver.
Tip: Install the sensor orthogonally!
How Do Reflex Light Barriers Fit in the Portfolio?
Energetic Reflex Sensors
Energetic reflex sensors are used for object detection without a background. They check objects for presence, check stack heights or carry out counting tasks.
Energetic reflex sensors are used for object detection without a background. They check objects for presence, check stack heights or carry out counting tasks.
Reflex Sensors with Background Suppression
Reflex sensors with background suppression detect and measure objects in front of a specified background irrespective of object properties such as shape, color or gloss.
Reflex sensors with background suppression detect and measure objects in front of a specified background irrespective of object properties such as shape, color or gloss.
Universal Retro-Reflex Sensors
Universal retro-reflex sensors are also suitable for detecting shiny, chrome-plated or mirrored surfaces thanks to the integrated polarization filter.
Universal retro-reflex sensors are also suitable for detecting shiny, chrome-plated or mirrored surfaces thanks to the integrated polarization filter.
Retro-Reflex Sensors for Transparent Objects
In addition to glossy, chrome-plated or mirrored surfaces, retro-reflex sensors for transparent objects also detect and count glass, PET or films using red light.
In addition to glossy, chrome-plated or mirrored surfaces, retro-reflex sensors for transparent objects also detect and count glass, PET or films using red light.
Through-Beam Sensors
Thanks to their long range, through-beam sensors ensure reliable detection even in heavily soiled environments. Variants with laser light can detect even the smallest objects.
Thanks to their long range, through-beam sensors ensure reliable detection even in heavily soiled environments. Variants with laser light can detect even the smallest objects.
Reflex Light Barriers
Reflex light barriers are ideal for contactless object detection without reflectors via red LED light, regardless of object color, shape and surface.
Typical Applications of Sensors with Barrier and Reflex Mode
Reflex light barriers can be used in a variety of ways. Thanks to their reliable barrier and reflex mode, they are ideal for detecting objects regardless of color, shape and surface:
| Range | Response time | Object detection before background | Detection of semi-transparent objects | Detection of glossy and dark objects | |
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| Reflex sensors with background suppression |
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| Universal retro-reflex sensors |
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| Retro-reflex sensors for transparent objects |
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| Through-Beam Sensors |
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Reflex light barriers can be used in a variety of ways. Thanks to their reliable barrier and reflex mode, they are ideal for detecting objects regardless of color, shape and surface:
| Reflex Light Barriers | |||||
|---|---|---|---|---|---|
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Range
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Response time
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Object detection before background
|
Detection of semi-transparent objects
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Detection of glossy and dark objects
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| Energetic reflex sensors | |||||
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Range
|
Response time
|
Object detection before background
|
Detection of semi-transparent objects
|
Detection of glossy and dark objects
|
|
| Reflex sensors with background suppression | |||||
|
Range
|
Response time
|
Object detection before background
|
Detection of semi-transparent objects
|
Detection of glossy and dark objects
|
|
| Universal retro-reflex sensors | |||||
|
Range
|
Response time
|
Object detection before background
|
Detection of semi-transparent objects
|
Detection of glossy and dark objects
|
|
| Retro-reflex sensors for transparent objects | |||||
|
Range
|
Response time
|
Object detection before background
|
Detection of semi-transparent objects
|
Detection of glossy and dark objects
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| Through-Beam Sensors | |||||
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Range
|
Response time
|
Object detection before background
|
Detection of semi-transparent objects
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Detection of glossy and dark objects
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