Technical Guide

Sensors

Photoelectric Sensors

Displacement Sensors

Proximity Sensors

Photomicro Sensors

Rotary Encoders

Ultrasonic Sensors

Pressure Sensors

Displacement and Measurement Sensors

These Sensors can be used to measure distances and heights. A wide variety of models is available, including Laser Sensors, LED Sensors, Ultrasonic Sensors, Contact Sensors, Eddy Current Sensors, and more.

Principle of Measurement of the Optical Displacement Sensor

Light from the light source is condensed by the lens and directed onto the object.
Light reflected from the object is condensed onto a one-dimensional position sensing device (PSD)* by the receiving lens. If the position of the object (the distance to the measuring device) changes, the image formation positions on the PSD will differ, and if the balance of the two PSD outputs changes, the image formation positions on the PSD will differ and the balance of the two PSD outputs changes.
If the two outputs are A and B, calculate A/(A + B) and use appropriate values for the span coefficient "k" and the offset "C".

   can be obtained.

The value measured is not the illuminance (brightness), but the two output displacements A and B, and thus even if the received light intensity changes because the distance to the object changes, the result is not affected and linear output proportional to the distance difference and position shift is obtained.
 

Optical System of the Displacement Sensor

Regular reflection model

Light from the object is directly received by regular reflection, and stable measurement is possible of metal and other objects with a glossy surface.
 

Diffuse reflection model

A light beam is projected perpendicularly onto the surface of the object, and the diffuse light that is reflected back is received for a wide measurement area.

Displacement & Measurement Sensor Glossary
 

Resolution
 

This is the width, expressed in terms of the distance, of the fluctuation in the linear output when the measured object is still.

Linearity
 

Error with respect to ideal straight line of linear output Normally the percentage of the measurement range (full scale: FS), expressed in the format "1%".

Temperature drift
 

The amount of variation of linear output with respect to changes in the ambient temperature.
Normally the percentage of the measurement range (full scale: FS), expressed in the format []%FS/°C.

Example: 0.03%FS/°C (FS = 20 mm)
 

Response time
 

Linear output when the displacement and width of the object are changed to steps.
In analog output, the time required for 10% to 90% change is expressed in terms of the "response time".

Response time and resolution
 

In general the displacement, response time, and resolution are correlated as shown in the following diagram.

• When you wish to precisely measure displacement, select a slower response time setting. (This reduces responsiveness.)

• When you need a fast response, select a faster response time setting. (This reduces the resolution.)
  
   

Recommended Products

	Smart Sensors (2D CMOS Laser Type)     ZS Precise spot detection, wide-range detection and long-distance detection.
	Smart Sensor (Laser Displacement Type)     ZX-L-N Plenty of smart functions inside a compact body with a full range of laser types.
	2D Profile Measuring Sensor     ZG Ultra wide laser beam and super high-speed measurement.