# Why must Master and Slave sensor web paths be equal distance to the lamination nip?

> 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 ma...

**Last updated:** 2026-02-01

**Source:** https://live-roll2roll.pantheonsite.io/resources/faq/why-must-master-and-slave-sensor-web-paths-be-equal-distance-lamination-nip

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## Question

Why must Master and Slave sensor web paths be equal distance to the lamination nip?

## Short Answer

Equal path lengths ensure the Slave guide corrects for a Master error at the exact moment that error reaches the lamination point.

## Detailed Answer

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](https://r2r.tech/products/controllers) can apply dynamic compensation—electronically delaying the feed-forward signal to match the transport time difference.

**Category:** Installation, Technical

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## About Roll-2-Roll Technologies

Roll-2-Roll Technologies designs and manufactures patented fiber-optic web position sensors and advanced web guiding controllers — the precision measurement and control core of modern roll-to-roll manufacturing. Spun out of Oklahoma State University's Web Handling Research Center and trusted by Fortune 500 medical, battery, and nonwovens manufacturers, our patented sensors work without recalibration at ±0.1mm accuracy up to 760 mpm — typical customer outcomes are 50%+ less downtime and payback under six months. Headquartered in Stillwater, Oklahoma, our team of PhDs, controls engineers, and industry veterans extends the sensor + controller core into complete web guide systems including stepper-motor-based linear actuators (RLA, BLA, LHS).

- Website: https://r2r.tech
- Phone: +1 (888) 290-3215
- Email: sales@r2r.tech