Quick Answer:
Short Answer
No. Single wide sensors (up to 960mm) can see both edges. Wide webs may need two sensors.
Not necessarily. Roll-2-Roll offers two approaches: For wide webs with significant width variation, use two sensors mounted on opposite sides. For narrow to medium webs (up to 960 mm), a single wide sensor like the ODC 480, ODC 768, or ODC 960 can see both edges simultaneously. The single-sensor approach simplifies installation (no alignment between sensors required) and works well for label converting, battery electrode, and narrow web applications.