Precision Lightband Sensors Type BS

The BS-type sensors from STM generate lightbands of extraordinary uniformity. Instead of being concentrated in single light beams as with all “normal” optosensors, the intensity of light here is homogeneously distributed over the complete width of the measuring field.

With a single light beam, only at the location where a beam is positioned is detection possible. In contrast, lightbands allow measurement in a complete plane, and can thus provide additional information about an object, e.g., its size, shape or exact edge position. The BS sensor, therefore, measures the percent coverage of the lightband which is caused by the enclosed object. Due to the extraordinary homogeneity of the lightband, the sensitivity, or better yet, the exactness of this measurement, is equitably high in all positions within the band.

Depending on the kind of use, there are a multitude of application possibilities which are impossible with usual optosensors, including light curtains, with the presence of gaps between the individual beams.

Here are only a few examples for typical applications:

• Utilization as a classical web edge sensor with an amplifier, V10-C or V10-D,that provides an analog output signal according to the edge position. Due to the homogeneity of the lightband it features high linearity and accuracy. Application Example: High-precision web steering.
• With an analog amplifier,V10-C or V10-D, achievable edge position accuracy of up to 0.1mm over the entire measuring range is possible. Application Example: Analog acquisition of the profile of parts on a conveyor belt. 
• Detection with uniform sensitivity within the whole band.By combination with a dynamic amplifier, V10-H,the sensor functionality is comparable to an optical frame sensor. Application Example: Counting of falling parts or drops.
• Through operation with a switching amplifier, e.g., V10-B,the system works as a non-contact switch. Application Example: Detecting leading edge on mechanical feeders in folding machines—where high precision for the leading edge detection is required, although the lateral position of the object may vary.

The BS-type sensors from STM are available in two basic body styles: As forks—this simplifies alignment and installation—or as separate emitter-and-receiver modules, which can be mounted freely—this results in maximum flexibility for the application.

In both designs the standard lightband widths are 30mm or 80mm. The usual fork leg widths are 40mm and 80mm apart. And for the separate emitter-and -receiver modules, the maximum distances between each module can reach up to 500mm apart.

If the customer needs different lightband widths than the standard, this can be provided upon request.

No other optosensor manufacturer can offer a modular design with comparable flexibility!