---
title: "Quick Start: Unwind/Rewind Web Guide — Master/Slave Guiding — SCU6x"
application: web-guiding-unwind-rewind
variant: master-slave
controller: scu6x
valid_sensors: ["ODC 48", "ODC 96", "ODC 192", "ODC 288", "ODC 384", "ODC 480", "ODC 768", "ODC 960"]
output_type: master-slave
estimated_time: "varies"
last_updated: "2026-09-16"
guide_url: "https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x"
pdf_url: "https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.pdf"
---

# Quick Start: Unwind/Rewind Web Guide — Master/Slave Guiding — SCU6x

> Install, wire, and configure a Roll-2-Roll® ODC sensor with a SCU6x controller for unwind/rewind web guide.

## What You'll Achieve

After completing this guide, your slave web follows the master web's side-to-side position — the stand shifts the roll to keep the two layers aligned.

## What You Need

### Products

- [SCU6x](https://r2r.tech/products/sensor-controller/scu6x) web-guide controller with the MxD (7 A) driver, as ordered for the RLA. Unwind/rewind requires the SCU6x MxD option (with or without C(x)D or DIO); port Z1 supplies the driver power.
- RLA sized to your roll (floating -TG mount) — see the sizing article under Learn More
- RC-050A regeneration clamp — absorbs the energy the shifting roll drives back into the actuator
- Two ODC Family infrared sensors — one master, one slave, on the two web paths
- Quick Disconnect Sensor Cable - 3m (10 ft) (U2-01975)
- Second Quick Disconnect Sensor Cable (U2-01975) for the slave sensor
- Sensor mounting rail and bracket (SKU 7-020001 for 1 in sensors, SKU 7-020006 for 1.5 in)
- 24 V DC Input Power Cable for SCU6x or 1DC - 5m (21218x-5m)
- Driver-power cable (SKU 21229x) for the MxD driver
- Actuator cordset for the RLA (SKU 21225, T-coded high-current)
- Servo-center proximity sensor (SKU 7-140004)
- High-current driver-power supply (SKU PS-10001, 24/48 VDC) for the RLA driver
- 24 VDC control supply, 5 A minimum (SKU 0-100006)

### Prerequisites

- The machine is shut down and locked out per your facility's procedures.
- A 24 VDC supply (5 A minimum) is available at the install location.
- A roll is loaded on the stand, with web ready to thread.
- Keep the SCU6x Sensor and Web Guide Controller User Manual within reach (/documentation/manuals/scu6x-sensor-and-web-guide-controller-user-manual) — you'll use it while commissioning.

## Install the Web Guide

Install the [Roll-2-Roll® Web Guide](https://r2r.tech/products/web-guides) in two stages: first set up the shifting roll stand — carriage, linear bearings, and the high-thrust actuator — then mount the sensor for your guiding mode.

### Install and Align the Roll Stand

- Bolt the roll-stand base to the machine through its base-plate holes.
- Level the stand: set the roll axis parallel to the machine idlers and square to web travel, with no tilt to either side. Check it with a machine square or a tram rod — whichever you have.
- Slide the moving carriage by hand through its full travel on its linear bearings. It should move smoothly end to end with no binding, notching, or stiff spots. If it binds, clean and re-lubricate or replace the linear bearings before you fit the actuator.

### Retrofitting an existing stand?

- Reuse your existing roll-stand carriage and linear bearings — the moving structure stays.
- Replace the controls and the actuator: the old actuator and its drive come off, and the Roll-2-Roll controller, sensor, and actuator go on. Before you remove the old actuator, sketch or photograph how it attaches at both ends and note its fully-retracted and fully-extended positions — the new actuator matches that geometry and stroke.
- The rest of the install is identical to a new stand.

### Mount the Actuator

- Match the actuator to the stand's mount before you install it: a fixed (-RF) structure takes an LHS-RF actuator — LHS is the only family offered with a fixed mount. A floating (-TG) structure takes a floating-mount actuator sized to the load — RLA for heavy rolls (the unwind/rewind default), BLA for intermediate loads and wide webs needing 6 in of stroke or more, or LHS-TG for small loads.
- Bench-test the actuator before you mount it. Connect its cables to the controller, apply power, and jog it end to end from the operator interface. It should travel smoothly the full stroke. If it doesn't move or it stalls, re-check the cabling and the supply before you commit it to the machine.
- Floating (-TG) mount — connect the front rod eye to the moving carriage and the rear spherical bearing or clevis to the stationary base. Add an anti-rotation feature at the spherical-bearing end so the actuator body can't spin, and let the pins carry the rotation so the actuator self-aligns as the stand moves.
- Fixed (-RF) mount — fasten the mounting plate so the actuator's linear motion is exactly in line with the carriage travel, and apply thread-locker to any fastener screwed directly into the actuator.
- Check the alignment — jog the stand slowly across its full travel and watch it move without struggling or binding. If it fights at any point, loosen the mounts, re-square the actuator to the carriage, and re-check.
- Match the stroke to the stand travel — confirm the actuator's fully-retracted and fully-extended positions coincide with the carriage's travel extremes, and center the stroke. If the actuator over-travels the stand, reduce the digital stroke length in the controller; if it under-travels, add mechanical stops.
- Install the servo-center proximity sensor (SKU 7-140004) so it switches exactly at mid-stroke — with the stand centered, position it to see metal within 2 mm for one half of the travel and clear space for the other half. Jog through mid-stroke and confirm its LED toggles on and off right at center; the controller uses this transition to find the actuator's home position during commissioning.
- Connect the RC-050A regeneration clamp into the actuator drive circuit as shown in the wiring diagram — a heavy roll decelerating or reversing drives regenerated energy back into the drive, and the clamp dissipates it.

### Mount the Driver Power Supply and Regen Clamp

- Mount the 24/48 VDC driver power supply (SKU PS-10001) in the machine's electrical cabinet — it is a DIN-rail / chassis-style supply. The SCU6x's MxD driver is built into the controller, so there is no separate driver box to mount.
- Route the Z1 driver-power cable (SKU 21229x) from the cabinet to the SCU6x's Z1 driver-power port. The cable splits to the supply and the RC-050A regeneration clamp.
- The RC-050A clamp is DIN-rail mounted — clip it to the rail next to the 24/48 VDC supply in the cabinet and connect it to the clamp leg of the Z1 split.

### Choose the Sensor Location and Mount the Sensor

- **Unwind stand:** mount the sensor in the first free span downstream of the idler that follows the roll — it has to read the web after the shifting stand has moved it, not before.
- **Rewind stand:** mount the sensor just upstream of the fixed idler ahead of the rewind stand, so it reads the edge before the web winds on. Mount it on the rewind frame itself, not the machine frame — rewind guiding chases the web, and the sensor must move with the stand to hold the relative position between the web and the rewind roll.
- Clamp the sensor bracket to its rail, but don't fully tighten it yet.
- Set the working distance from the sensor face to the web to 5–15 mm (0.2–0.6 in).
- Keep everything at least 150 mm (6 in) behind the web clear in the sensor's view — the camera-style sensor can otherwise pick up background objects.
- Guiding a shiny, metallic, or clear web? Tilt the sensor a few degrees toward the web so its angled light returns to the lens, then re-check the working distance.
- Tighten the bracket.

### Pre-Power Mechanical Checks

- Do these with the power off, before you commission. With the actuator mounted, don't force the stand by hand — you can back-drive the actuator.
- Confirm the actuator is mounted in line with the carriage travel and its retracted and extended limits line up with the stand's travel extremes.
- Confirm the servo-center proximity sensor is installed and its LED changes state as the carriage passes mid-stroke.
- Confirm the RC-050A regeneration clamp is connected in the actuator drive circuit per the wiring diagram.
- Confirm every cable is routed and strain-relieved, and that nothing is powered yet.

**Reference documents:**

- [Web Guide Installation Checklist](https://r2r.tech/documentation/manuals/web-guide-installation-checklist.md)
- [Retrofit Installation Checklist](https://r2r.tech/documentation/manuals/retrofit-installation-checklist.md)
- [Servo Center and Servo Installation](https://r2r.tech/documentation/manuals/servo-center-servo-installation.md)

## Install the Sensor

### Install the Sensors — Master/Slave Guiding

- Master/slave guiding uses two ODC infrared sensors on two separate web paths: a master sensor on the master (reference) web and a slave sensor on the web this stand shifts.
- Line up the master and slave sensors at the same point across the machine, relative to the machine centerline.
- Make the web-path length from the master sensor to the lamination point equal to the path length from the slave sensor to the lamination point — this timing has to match.
- Mount both sensors the same way round (matching camera pixel direction) so the controller reads both webs consistently.

## Configure & Verify

Power up the controller and commission the guide, one checked step at a time.

### Master/Slave Guiding — Power Up and Commission

Commission master/slave guiding — set up the slave guide first, then bring in the master so the slave web follows it.

1. Power on the controller. If it wakes in Automatic, switch to Manual — every step below runs from Manual.
2. Set both sensors to edge sensing. The master sensor reads the master (reference) web; the slave sensor reads the web this stand shifts.
3. Disable the master sensor for now — you'll commission the slave guide on its own first.
4. Set the slave sensor's orientation to Left or Right to match its edge, by pressing the sensor button (Sensor 1 or Sensor 2) on the home screen to cycle Left → Center → Right, and check it on the Web Position Indicator — a dark region on the matching side. If it reads all dark or all light, fix the working distance or orientation before continuing.
5. Check the jog direction. Tap Jog Left, then Jog Right, and watch the roll stand. It should shift the way each button says. If it moves the opposite way, reverse Motor Polarity under Power User → Actuator → Motor Polarity, then jog again to confirm.
6. Servo-center the actuator. Tap Servo Center and let the stand travel to its home position (half the actuator stroke each way). If it heads away from home, reverse Servo Center Polarity under Power User → Actuator → Servo Center Polarity, then servo-center again.
7. Set the guide point for the slave web, then switch to Automatic and confirm the slave web corrects the right way. If it steers away from the guide point, reverse Error Polarity under Power User → Controller. Get steady slave guiding before adding the master.
8. Enable the master sensor and set its orientation to match its edge the same way (by pressing the sensor button (Sensor 1 or Sensor 2) on the home screen to cycle Left → Center → Right), then check it on the Web Position Indicator. Turn on the master/slave function.
9. Confirm which sensor is master and which is slave — the master supplies the guide-point offset, the slave is the edge the actuator follows.
10. Check the master/slave polarity. Shift the master web off its sensor center and watch the slave web move the same way. If the slave moves the opposite way, flip the master/slave polarity, then re-check.
11. Prove the safety hold. Lock on Lost Edge watches the slave web — pull the slave web out of its sensor's view and confirm the stand holds its last position. When the slave web tracks the master and the hold works, your unwind/rewind master/slave guide is commissioned.

## PLC Integration

Web guiding controllers support remote command via two routes: Industrial Ethernet PLC remote control, and the DIO option (discrete dry-contact inputs). Both allow a PLC or supervisory system to command guide mode and position without manual touchscreen interaction.

- Route 1 — PLC remote control (C(x) models): send auto mode on/off, jog, servo center, and guide-point commands over Industrial Ethernet (EtherNet/IP, PROFINET, EtherCAT)
- Route 2 — DIO option: discrete dry-contact 24 V NPN inputs for hard-wired remote on/off and mode switching — no Industrial Ethernet required; wired directly from PLC digital outputs or relay contacts
- Both routes can coexist — Ethernet for data and fine control, DIO for hard-wired safety/interlock inputs
- Lock on Lost Edge: when the web edge exits the sensor field of view during edge guiding, actuator motion is inhibited — prevents runaway
- Loss of Contrast Inhibit: for line/contrast guiding, actuator motion is inhibited if contrast is lost until the target feature is re-acquired

**Register map:**

- [SCU6x Industrial Ethernet Register Map](https://r2r.tech/documentation/manuals/scu6x-industrial-ethernet-register-map-v41.md)

**Support files:**

- [EDS File (EtherNet/IP)](https://r2r.tech/documentation/support-files/ethernetip-eds-file-scu6x-firmware-version-41-using-hilscher-module.md)
- [Add-on Instruction (AOI) for Studio 5000](https://r2r.tech/documentation/support-files/rockwellab-add-instructions-scu6x-cedmced-controller-v41.md)

## Go Further

### Related Quick Start Guides

- [Intermediate Web Guide](https://r2r.tech/resources/quick-start/web-guiding-intermediate/edge/scu6x.md) — Guide the web mid-machine with an intermediate web guide and LHS actuators
- [Retrofit an Existing Web Guide](https://r2r.tech/resources/quick-start/retrofit/edge/scu6x.md) — Upgrade a legacy or competitor web guide with Roll-2-Roll sensors and controllers

### Learn More

- [Unwind and Rewind Guides — Design and Installation Considerations](https://r2r.tech/articles/unwind-and-rewind-guides-design-and-installation-considerations.md)
- [How to Size an Actuator for Unwind/Rewind Web Guides](https://r2r.tech/articles/how-to-size-an-actuator-for-unwind-and-rewind-web-guides.md)

### Reference Documents

- [Web Guide Installation Checklist](https://r2r.tech/documentation/manuals/web-guide-installation-checklist.md)
- [Servo Center and Servo Installation](https://r2r.tech/documentation/manuals/servo-center-servo-installation.md)
- [RLA Product Page](https://r2r.tech/products/actuators/rla.md)

## Available Sensor Models

Select a sensor model at the guide page to see datasheets, 2D drawings, 3D models, and STEP file downloads.

- [ODC 48](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-48) (48 mm)
- [ODC 96](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-96) (96 mm)
- [ODC 192](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-192) (192 mm)
- [ODC 288](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-288) (288 mm)
- [ODC 384](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-384) (384 mm)
- [ODC 480](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-480) (480 mm)
- [ODC 768](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-768) (768 mm)
- [ODC 960](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu6x.md?sensor=odc-960) (960 mm)

## Related Quick Start Guides

- [Splice Detection — Industrial Ethernet — 1DC Series](https://r2r.tech/resources/quick-start/splice-detection/ethernet/1dc.md)
- [Splice Detection — Industrial Ethernet — SCU6x](https://r2r.tech/resources/quick-start/splice-detection/ethernet/scu6x.md)
- [Splice Detection — Digital Output — SCU6x](https://r2r.tech/resources/quick-start/splice-detection/digital/scu6x.md)
- [Position Measurement — Analog Output — SCU5](https://r2r.tech/resources/quick-start/position-measurement/analog/scu5.md)
- [Position Measurement — Industrial Ethernet — SCU5](https://r2r.tech/resources/quick-start/position-measurement/ethernet/scu5.md)
- [Position Measurement — Industrial Ethernet — SCU6x](https://r2r.tech/resources/quick-start/position-measurement/ethernet/scu6x.md)
- [Position Measurement — Industrial Ethernet — 1DC Series](https://r2r.tech/resources/quick-start/position-measurement/ethernet/1dc.md)
- [Web Width Measurement — Analog Output — SCU5](https://r2r.tech/resources/quick-start/web-width/analog/scu5.md)
- [Web Width Measurement — Digital Monitoring — SCU5](https://r2r.tech/resources/quick-start/web-width/digital/scu5.md)
- [Web Width Measurement — Industrial Ethernet — SCU5](https://r2r.tech/resources/quick-start/web-width/ethernet/scu5.md)
- [Web Width Measurement — Digital Monitoring — SCU6x](https://r2r.tech/resources/quick-start/web-width/digital/scu6x.md)
- [Web Width Measurement — Industrial Ethernet — SCU6x](https://r2r.tech/resources/quick-start/web-width/ethernet/scu6x.md)
- [Web Width Measurement — Industrial Ethernet — 1DC Series](https://r2r.tech/resources/quick-start/web-width/ethernet/1dc.md)
- [Multiple Web Width Measurement — Industrial Ethernet — SCU6x](https://r2r.tech/resources/quick-start/multi-web-width/ethernet/scu6x.md)
- [Multiple Web Width Measurement — Digital Monitoring — SCU6x](https://r2r.tech/resources/quick-start/multi-web-width/digital/scu6x.md)
- [Multiple Web Width Measurement — Industrial Ethernet — 1DC Series](https://r2r.tech/resources/quick-start/multi-web-width/ethernet/1dc.md)
- [Intermediate Web Guide — Edge Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/edge/scu5.md)
- [Intermediate Web Guide — Edge Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/edge/scu6x.md)
- [Intermediate Web Guide — Center Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/center/scu5.md)
- [Intermediate Web Guide — Center Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/center/scu6x.md)
- [Intermediate Web Guide — Line Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/line/scu5.md)
- [Intermediate Web Guide — Line Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/line/scu6x.md)
- [Intermediate Web Guide — Contrast Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/contrast/scu5.md)
- [Intermediate Web Guide — Contrast Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/contrast/scu6x.md)
- [Intermediate Web Guide — Master-Slave Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/master-slave/scu5.md)
- [Intermediate Web Guide — Master-Slave Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/master-slave/scu6x.md)
- [Intermediate Web Guide — Open-Loop Oscillation — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/oscillation-open/scu5.md)
- [Intermediate Web Guide — Open-Loop Oscillation — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/oscillation-open/scu6x.md)
- [Intermediate Web Guide — Closed-Loop Oscillation — SCU5](https://r2r.tech/resources/quick-start/web-guiding-intermediate/oscillation-closed/scu5.md)
- [Intermediate Web Guide — Closed-Loop Oscillation — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-intermediate/oscillation-closed/scu6x.md)
- [Unwind/Rewind Web Guide — Edge Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/edge/scu5.md)
- [Unwind/Rewind Web Guide — Edge Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/edge/scu6x.md)
- [Unwind/Rewind Web Guide — Center Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/center/scu5.md)
- [Unwind/Rewind Web Guide — Center Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/center/scu6x.md)
- [Unwind/Rewind Web Guide — Line Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/line/scu5.md)
- [Unwind/Rewind Web Guide — Line Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/line/scu6x.md)
- [Unwind/Rewind Web Guide — Contrast Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/contrast/scu5.md)
- [Unwind/Rewind Web Guide — Contrast Guiding — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/contrast/scu6x.md)
- [Unwind/Rewind Web Guide — Oscillation (Open Loop) — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/oscillation-open/scu5.md)
- [Unwind/Rewind Web Guide — Oscillation (Open Loop) — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/oscillation-open/scu6x.md)
- [Unwind/Rewind Web Guide — Oscillation (Closed Loop) — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/oscillation-closed/scu5.md)
- [Unwind/Rewind Web Guide — Oscillation (Closed Loop) — SCU6x](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/oscillation-closed/scu6x.md)
- [Unwind/Rewind Web Guide — Master/Slave Guiding — SCU5](https://r2r.tech/resources/quick-start/web-guiding-unwind-rewind/master-slave/scu5.md)
- [Retrofit an Existing Web Guide — Edge Guiding — SCU5](https://r2r.tech/resources/quick-start/retrofit/edge/scu5.md)
- [Retrofit an Existing Web Guide — Edge Guiding — SCU6x](https://r2r.tech/resources/quick-start/retrofit/edge/scu6x.md)
- [Retrofit an Existing Web Guide — Center Guiding — SCU5](https://r2r.tech/resources/quick-start/retrofit/center/scu5.md)
- [Retrofit an Existing Web Guide — Center Guiding — SCU6x](https://r2r.tech/resources/quick-start/retrofit/center/scu6x.md)
- [Retrofit an Existing Web Guide — Contrast Guiding — SCU5](https://r2r.tech/resources/quick-start/retrofit/contrast/scu5.md)
- [Retrofit an Existing Web Guide — Contrast Guiding — SCU6x](https://r2r.tech/resources/quick-start/retrofit/contrast/scu6x.md)
- [Retrofit an Existing Web Guide — Line Guiding — SCU5](https://r2r.tech/resources/quick-start/retrofit/line/scu5.md)
- [Retrofit an Existing Web Guide — Line Guiding — SCU6x](https://r2r.tech/resources/quick-start/retrofit/line/scu6x.md)
- [Retrofit an Existing Web Guide — Master-Slave Guiding — SCU5](https://r2r.tech/resources/quick-start/retrofit/master-slave/scu5.md)
- [Retrofit an Existing Web Guide — Master-Slave Guiding — SCU6x](https://r2r.tech/resources/quick-start/retrofit/master-slave/scu6x.md)

## Support

- Email: experts@r2r.tech
- Phone: +1-888-290-3215