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What You'll Achieve
After completing this guide, your web runs centered between its two edges — the stand shifts the roll to hold the centerline as the edges wander.
Estimated time: ~30–60 minutes
What You Need
SCU6x · Center Guiding — What You Need
Prerequisites
Install the Web Guide
Install the Roll-2-Roll® Web Guide 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.
DANGER
Match the actuator mount to your existing structure
Identify whether your existing carriage uses a fixed (-RF) or floating (-TG) mount before ordering or installing the actuator. Fixed structures take an LHS-RF actuator; floating structures take an LHS-TG, BLA, or RLA sized to the load. Installing a fixed-mount actuator on a floating structure — or a floating-mount actuator on a fixed structure — will damage the actuator.
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
Install the Sensor
Install the Sensors — Center Guiding
- Center guiding uses two ODC infrared sensors — one over the left edge, one over the right edge. Set their spacing from your web width, and give each edge room in its sensor window for the roll to shift both ways.
- Mount both sensors the same way round (matching camera pixel direction) so the controller reads both edges consistently.
Wire the System
Configure & Verify
Power up the controller and commission the guide, one checked step at a time.
Center Guiding — Power Up and Commission
Commission two-sensor center guiding — set both sensors, prove the high-thrust motion, then hold the web centered in automatic.
- Power on the controller. If it wakes in Automatic, switch to Manual — every step below runs from Manual.
- Set each sensor's electronic orientation by pressing the sensor button (Sensor 1 or Sensor 2) on the home screen to cycle Left → Center → Right: the sensor over the left edge to Left, the one over the right edge to Right.
- Check both on the Web Position Indicator (the home screen shows what the sensors see). With the web threaded, you should see a dark region on the left AND a dark region on the right — one per sensor. If either side reads all dark or all light, that sensor isn't seeing its edge or its orientation is wrong — re-check its working distance and position. Don't continue until both edges show.
- 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.
- 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.
- Set the guide point. Tap Reset Guide Point to lock onto the web's current center as the target. (To shift the target, drag the guide-point bar and press Accept.)
- Switch to Automatic. The actuator now shifts the roll stand to keep the web centered as both edges wander, and the Web Position Indicator holds steady. If the controller won't enter Automatic, a sensor isn't detecting its edge — go back to step 3.
- Check the correction direction. Nudge the web off center. The stand should shift to bring it back. If it drives the web further off, reverse Error Polarity under Power User → Controller, then watch it correct again.
- Fine-tune the position. Still in Automatic, tap Jog Right (+) or Jog Left (−) to nudge the centered web to the exact spot — about 0.25 mm (0.01 in) per tap.
- Prove the safety hold. Pull the web clear of both sensors. The actuator should freeze and hold the stand until the web returns. When it does, your unwind/rewind center 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
📄 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
- Intermediate Web Guide — Guide the web mid-machine with an intermediate web guide and LHS actuators
- Retrofit an Existing Web Guide — Upgrade a legacy or competitor web guide with Roll-2-Roll sensors and controllers
Learn More
- Unwind and Rewind Guides — Design and Installation Considerations
- How to Size an Actuator for Unwind/Rewind Web Guides
Need Help?
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