High-speed laser line sensor for difficult-to-measure surfaces

Posted to News on 14th May 2013, 13:33

High-speed laser line sensor for difficult-to-measure surfaces

Micro-Epsilon is launching the optoNCDT 2300LL non-contact laser line displacement sensor, which provides high-speed measurement of shiny metallic, rapidly changing, rough or other difficult-to-measure surfaces. Rather than using a spherical or point-shaped laser spot, the new optoNCDT 2300LL sensor uses a laser line and special software algorithms to filter out any interference caused by very small (sub-micrometre) surface defects on shiny objects such as polished metals, mild steel and rubber.

Intelligent software

The sensor uses a special cylindrical lens that widens the laser spot; although this shape appears as oval to the human eye, the actual shape is a very small line. Measurements using this laser line are then averaged using Micro-Epsilon's patented software algorithms to reduce any interference caused by surface roughness, defects, indentations or sub-micrometre holes. A suitable application for the optoNCDT 2300LL is therefore on structured surfaces, where the distance to the surface and not the structure itself need to be measured. The distance measurement should not be influenced by the structure of the surface but, instead, should provide a constant, reliable value of the distance from the target.

Fast, integrated measurement control

Micro-Epsilon's optoNCDT 2300LL is a self-contained laser displacement sensor that requires no separate controller. The sensor provides a high measuring speed of up to 49.02kHz. Although competing sensors in the market claim to offer similar measuring rates and resolution, the optoNCDT 2300LL is said by Micro-Epsilon to be the only sensor that offers such a high measuring speed and an integral controller. While some competing sensor manufacturers offer laser sensors with similar measuring speeds and resolutions, their high resolution is only achieved by applying a high averaging factor, which then reduces the dynamic speed of the laser. The optoNCDT 2300LL achieves high resolution and high measuring speeds without any averaging.

Connectivity and output management

This sensor also offers a range of interfaces including Ethernet, EtherCAT, RS422 and analogue output via the CSP2008 controller. The sensor can now be configured remotely by using a web browser interface. This direct connection means a user can store parameters for a particular application, which can then be uploaded to one or multiple sensors to reduce set-up times considerably. The sensor also provides various options for signal processing and data output, including peak selection (peak-to-peak), masking of the video signal, data reduction, averaging, exposure time, error status, time stamp, filtering and statistics (min and max).

Automatic compensation

The optoNCDT 2300LL uses Micro-Epsilon's new A-RTSC (Advanced Real Time Surface Compensation) technology, which enables the sensor to automatically compensate in real time for difficult-to-measure surfaces. A-RTSC is a further development of Micro-Epsilon's patented RTSC feature, which, when combined with high-speed software algorithms, reduces signal noise at high measurement speeds. When users need to measure against a shiny surface, for example, they require a sensor that is able to automatically 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 higher measurement accuracy due to lower noise level on the output signal.