The SR21 series slot sensors, with a 2mm slot width, provide a 12-bit (4096 step) resolution, a 20μs response time and a switching frequency of 25kHz.

The setting of the switching threshold is carried-out by simply pressing a button, or dynamically during label (or other reference) movement. The SR21-RG model with double red or green light is ideal for print registration mark detection on transparent films for automatic packaging.