Quick Answer:
No. Single wide sensors can see both edges up to their sensing range minus 20 mm (940 mm on a 960). Wider 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, a single wide sensor like the ODC 480, ODC 768, or ODC 960 can see both edges simultaneously: up to 460 mm on a 480, 748 mm on a 768, or 940 mm on a 960 (sensing range minus 20 mm of edge allowance). The single-sensor approach simplifies installation (no alignment between sensors required) and works well for label converting, battery electrode, and narrow web applications.