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Web Width Measurement — Industrial Ethernet — SCU6x

Quick Start Guides › Web Width Measurement
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Start here Select Your Sensor

Pick your ODC Family model to unlock datasheets, 3D models, support files, and your exact ordering list:

Not sure which size? Pick the sensor wide enough for your max expected wander + 10% margin. View all ODC Family models

Select your sensor model above to unlock datasheets, 3D models, support files, and your exact ordering list for this guide.

✓ What You'll Achieve

After completing this guide, wired to your SCU6x controller with width data available over Industrial Ethernet for your PLC.

Estimated time: ~2–3 hours

☐ What You Need

SCU6x Ethernet

Prerequisites

Sensor size selection: Single sensor: sensing range must exceed max web width + wander. Dual sensor: each sensor covers its respective edge + wander. If no single sensor is wide enough, use dual sensor.

SCU6x Output Options

SCU6x models differ by output: DIO provides digital GO/NO-GO pass/fail, C(x)D provides Industrial Ethernet, and C(x)DIO provides both. (SCU6x has no analog output.)

ModelOutputs
SCU6x C(x)DIndustrial Ethernet width data (overall width, left/right edge, centerline — loggable)
SCU6x C(x)DIOIndustrial Ethernet width data, plus digital GO/NO-GO pass/fail outputs

1 Install the Sensor

Edge-based web width measurement always uses free span mounting (web unsupported between rollers). Install the sensor so that the length of the sensor is parallel to the cross-machine direction (the width direction of the web).

Dual Sensor Installation: For dual-sensor width measurement, mount both sensors with the same camera orientation (facing the same direction). Then set their electronic orientation so that, relative to the web, one sensor tracks the left edge and the other tracks the right edge — see Sensor Installation Recommendations for orientation details.

Dual Sensor Setup

  • Position the left sensor to see the left edge, right sensor to see the right edge
  • Critical: mount both with the same camera (physical) orientation, but set their electronic orientation oppositely — the left sensor tracks the left edge, the right sensor the right edge
  • Each sensor needs margin for the full range of web widths (min to max) plus wander
  • Sensors do not need to be the same size — select each based on wander range at its edge
Light source: Infrared (IR) — default for most materials.

Reference Documents

2 Wire the System

Sensor connects via Quick Disconnect cable. Ethernet via M12 D-coded connector.

  1. Sensor: Connect Quick Disconnect Sensor Cable (U2-01975) from ODC sensor to SCU6x port S1 (and S2 for dual)
  2. Power: Connect 24 V DC Input Power Cable for SCU6x or 1DC (21218x-5m) to SCU6x port Z2
  3. Ethernet: Connect M12 to RJ45S, Shielded Cable (21222-3m) from SCU6x port P1 to PLC or network switch
Dual Sensor Wiring: Connect second sensor cable to controller port S2.

3 Configure & Verify

Web width measurement computes the distance between the detected left and right edges. The controller computes the width internally and provides the value directly.

Dual Sensor Width

Two sensors — one per edge — with the controller computing total width including the distance between sensors. Use when the web is wider than any single sensor. Not available for 1DC.

  1. Set each sensor's electronic orientation first — left sensor → left edge, right sensor → right edge — then perform single-sensor configuration for each
  2. Teach offset: place a known-width sample so both sensors see their edges
  3. Enter the known width value and press the Teach Offset button
  4. The controller computes the distance between sensors and stores it
  5. Optionally perform teach correction after teach offset for additional accuracy
Teach offset = one-time during installation (re-teach only when sensors are physically moved). Teach correction = optional per product change. Final width = raw measurement + offset + correction.
What success looks like: Both sensors show green indicators, width reflects the full web width, changing products produces the expected width change.

Common Configuration Mistakes

  • Not re-teaching correction after product change — accuracy degrades with different material
  • Forgetting teach offset — width will be wildly incorrect (missing distance between sensors)

View full configuration documentation

4 PLC Integration

The controller provides computed web width (with offset and correction applied) in dedicated registers. No PLC-side computation needed unless you prefer raw measurements.

  • Width is provided as a 16-bit register value with offset and correction applied
  • Raw edge positions (left and right) also available for PLC-side computation
  • For PLC-based tolerance monitoring: read width register, compare against nominal ± tolerance
  • Rockwell AOI handles pixel-to-mm conversion and bit unpacking automatically

📄 The register map, EDS file (EtherNet/IP), and Add-on Instruction (AOI) for Studio 5000 are in the Your Products section above — grouped on the product card with everything else you need to download.

+ Go Further

Related Quick Start Guides

  • Contrast-Based Width Measurement — Measuring coating width, feature width, and contrasting boundaries (coming soon)
  • Multiple Web Width Measurement — Measure multiple strips or webs simultaneously (SCU6x only)
  • Position Measurement — Measure edge, centerline, or contrast/line position
  • Splice Detection — Add splice detection alongside width measurement

Learn More

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Phone: +1-888-290-3215