Installation

Roll-2-Roll® Sensors are essentially one-dimensional line scan cameras—but without the complexity of traditional machine vision systems:

This is a major unlock: sophisticated 1D imaging capability that production staff can set up and maintain without specialized training or ongoing support costs.

Chasing systems move heavy machinery (slitter bases, coating heads) rather than lightweight web rollers. This imposes strict mechanical requirements:

1. Structural rigidity: The carriage must be stiff enough that its natural frequency exceeds the control frequency (typically >25-50Hz). If the sensor bracket wobbles, it creates "false error" and causes oscillation.
2. Breakaway force: The actuator must overcome static friction in the linear bearings. Roll-2-Roll® Actuators provide up to 2,000 lbf (8,900 N) thrust.
3. Acceleration over speed: The actuator must change direction fast enough to match web error rates. Speed alone won't help if the carriage can't accelerate quickly.

Rule of thumb: If the system oscillates or hunts, check carriage rigidity first—it's the most common cause of chasing failures.

Yes. Roll-2-Roll Technologies systems support multi-lane cascading alignment where each lane's edge position automatically sets the guide point for the next lane.

Example configuration (14 lanes):

• Each lane has two sensors: one monitors the "master" edge, one guides the web via a slave guide
• Lane 1's right edge position sets the guide point for Lane 2's slave guide
• Lane 2's right edge sets Lane 3's guide point, and so on
• Result: All lanes maintain edge-to-edge alignment automatically

For faster response: The SCU6x controller's industrial Ethernet connectivity enables a central PLC architecture where any lane change can instantly adjust guide points for all subsequent lanes simultaneously, rather than propagating lane-by-lane.

In Master/Slave guiding, timing is critical. The Slave guide must correct for a Master web movement at the exact moment that movement reaches the lamination nip.

The rule: Web path distance from Master Sensor → Lamination Nip should equal the distance from Slave Sensor → Lamination Nip.

Why it matters: If paths are unequal, the Slave might correct too early or too late (phase mismatch), causing misalignment at the actual lamination point.

The fix: If physical constraints prevent matching path lengths, Roll-2-Roll® Controllers can apply dynamic compensation—electronically delaying the feed-forward signal to match the transport time difference.

No. Roll-2-Roll® Sensors are available in apertures from 48mm to 960mm, allowing a single sensor to accommodate a wide range of web widths without repositioning.

For example, an ODC 288 sensor can detect edges anywhere within its 288mm (11.3 in) sensing range. Whether you're running a 100mm web or a 250mm web, the sensor detects the edge without adjustment.

This eliminates:

• Changeover time: No 2–5 minute delays for sensor repositioning between SKUs
• Operator error: No risk of incorrect sensor positioning
• Motorized positioners: No additional hardware cost or maintenance

Combined with material-agnostic detection (no recalibration between clear films, opaque substrates, or metallic foils), Roll-2-Roll® Sensors enable true "set and forget" operation.

Yes. The SCU5 and SCU6x controllers can process two sensors simultaneously with independent enable/disable control. This is ideal for bidirectional coating machines that run forward and backward between passes.

Typical dual-sensor configuration:

• Sensor 1: Mounted on the rewind moving frame—enabled during forward winding
• Sensor 2: Mounted on the fixed machine frame—enabled during reverse (unwind) direction

Instead of repositioning a single sensor when direction changes, operators simply switch which sensor is active via the controller touchscreen or a PLC command over EtherNet/IP, PROFINET, or EtherCAT.

This eliminates sensor repositioning time, enables instant direction changes, and simplifies machine design by removing the need for motorized sensor positioners.

In rewind chasing applications, the sensor must be mechanically attached to the shifting stand because the control system is designed to keep the sensor output at "zero." When the sensor moves with the roll, the system naturally drives the stand until the sensor aligns with the web edge.

If the sensor were fixed to the floor (like in intermediate guiding), the system would lose the relative position between the web and the roll face. The result would be telescoped or uneven rolls because the guide has no reference point for where the roll edge should be.

The sensor should observe the web at a fixed idler immediately upstream of the shifting stand. This provides a stable reference point while the stand—and sensor—move together.

The "fixed sensor rule" is fundamental to unwind guiding physics and is the opposite of rewind chasing:

The Logic: In unwind guiding, you are positioning the web to enter the machine at a specific target location. The sensor acts as that target. The controller moves the shifting stand until the web edge aligns with the fixed sensor position.

The Common Mistake: If you mount the sensor on the moving stand (as you would in a rewind chasing application), the sensor moves with the error. When the stand shifts left, the sensor shifts left too—so from the sensor's perspective, nothing has changed. The system cannot detect or correct the misalignment relative to the machine frame.

Proper Configuration:

• Sensor: Fixed to the machine frame (floor or fixed structure)
• At least one idler roller: Mounted on the shifting stand (moves with it)
• Sensor position: Immediately downstream of the shifting idler

This configuration ensures the sensor sees true web position relative to the machine, while the shifting idler maintains a consistent web plane as roll diameter changes.

Light source selection depends on your application:

• Infrared (880 nm): Best for most high-contrast applications including black lines on white, coating edges, and foil substrates. Works for both edge guiding and line guiding with the same sensor.
• White Light: Required for low-contrast patterns, subtle color differences, and applications where infrared cannot distinguish the feature.
• UV (385 nm): Required when the line is printed with UV-fluorescent ink that is invisible under normal lighting.

Contact Roll-2-Roll Technologies to discuss your specific material and line characteristics.

No. Traditional line sensors have narrow fields of view, requiring motorized positioning to physically move the sensor until it finds the line. Roll-2-Roll® Sensors have wide sensing ranges from 48 mm to 960 mm, allowing the sensor to see the entire potential line position area simultaneously. The sensor and controller automatically identify and track the line within this range—no mechanical movement required.