Laser sensor measures distances to reflective targets

The optoNCDT 1700DR is the latest addition to the company's existing optoNCDT1700 range of optical displacement sensors. The new sensor has a resolution of 0.1um at a measuring rate of 2.5kHz (without using an averaging filter). The optoNCDT 1700DR comes in three measuring ranges: 2mm, 10mm and 20mm, the latter claimed to provide a much higher range than current competing laser sensors on the market, which tend to offer a range of just a few millimetres.

This means industrial automation and OEM production companies can more accurately measure and monitor a variety of object parameters including thickness, roundness, position, deflection, tilt, displacement and vibration. The sensor can also be used for on- and off-line quality inspection tasks, dynamic part profiling and part recognition.

How it works

The optoNCDT 1700DR operates using the laser triangulation principle. A laser diode projects a visible point of light onto the surface of the target object. The light reflected from this point is then projected onto a CCD array. If the target changes position with respect to the sensor, the movement of the reflected light is projected on the CCD array and analysed to output the exact position of the target. The measurements are processed digitally in the integral controller. The data is output via analogue (I/U) and digital interface RS422 or USB.

The DR sensor has an integral controller at this performance level, which automatically compensates in real time for difficult-to-measure surfaces. The sensor's real-time surface compensation (RTSC) feature and patented high-speed software algorithms are claimed to reduce signal noise dramatically. When customers need to measure against a shiny surface, they ideally want to be able to adjust the laser pulse duration (or laser on time) of the sensor to give them the optimum exposure time on the CCD for that particular surface. This, in turn, provides a higher accuracy measurement due to lower noise level on the output signal.

Most suppliers can only offer sensors with a fixed measurement rate. This means that for most surfaces, other than matt white, the user has to rely on averaging the output data to reduce the noise level or error on the output, which gives lower accuracy. However, using Micro-Epsilon's software algorithms, the measurement rate on the sensor can be slowed down for difficult surfaces. This means that it can compensate in real time and that the exposure time of the laser light on the CCD can be optimised for the surface of the object to be measured, resulting in higher accuracy measurements.

Unique feature

Chris Jones, Managing Director at Micro-Epsilon UK, comments: "The optoNCDT 1700DR is optimised for the application, in terms of light intensity and the real-time surface compensation feature. In addition, at this kind of performance level, offering a sensor with an integrated controller is unique in the market. No other supplier can offer an integrated controller at these speeds and resolutions."

Micro-Epsilon's ILD 1700 configuration software tool comes as standard with each sensor. As well as an integrated controller, the optoNCDT 1700DR also incorporates a touch button keypad directly on the sensor, which enables users to adjust parameters without connecting a PC. The integrated limit switches make it possible to adjust the top and bottom warning or alarm limits for the sensor. Jones states: "Some competing laser sensors do offer this type of functionality, but not at this level of performance."

For more information about Micro-Epsilon's laser sensors and systems, go to www.micro-epsilon.co.uk/uk-en/Sensors/Optical---Laser/.