Is the edge, centre, printed line or object moving sideways from its target?
Engineering Selection Guide
Compare the control path before choosing web handling hardware
Start with material behaviour, the machine zone, operating range and integration constraints. Then narrow the controller, sensor, actuator, brake or clutch direction for the actual roll-to-roll line.
One Machine, Two Control Questions
Separate lateral position from web tension
Web guiding and tension control are complementary, but they solve different problems. Define each control target before selecting components.
Is pulling force changing with roll diameter, speed, acceleration or process load?
Where can sensing and correction occur, and what signals must connect to the machine?
Web Guiding Comparison
Choose the sensing principle around the real target
The table identifies practical starting points, not a final model recommendation. Test difficult materials and confirm the controller interface before release.
| Starting point | Target or material | Why it may fit | Confirm before selection | KRD path |
|---|---|---|---|---|
| Ultrasonic edge or centre sensing | Transparent and opaque non-breathable webs; useful where optical contrast varies | Does not rely on colour contrast or ambient light; the KRD matrix also identifies dusty-environment use | Breathability or porous structure, fork geometry, acoustic interference and measurement range | US-400 / US-500 |
| Photoelectric edge or centre sensing | Transparent or opaque film, paper, foil, metal and compatible textile webs | Contactless optical detection where the transmitted or reflected signal remains stable | Transparency, reflectivity, edge contrast, contamination, ambient conditions and mounting geometry | PS-400 / PS-500 |
| Line or mark sensing | Printed line, colour contrast, registration mark or defined feature | Uses a feature on the web when the material edge is not the control reference; these models can also support edge or centre modes | Print variation, contrast, lighting, target width and speed response | PS-260 / PS-261 |
| Camera multi-mode sensing | Edge, centreline, printed line, pattern or difficult-to-sense target | Supports edge, centre and line or pattern guiding across the broad material set shown in the KRD matrix | Field of view, resolution, lighting, target contrast, speed, controller interface and integration | HCCD |
Tension Control Comparison
Match the control method to how the machine changes
The appropriate path depends on whether the process can rely on operator settings, an estimated torque model or measured tension feedback.
| Control path | Typical starting condition | Main input | Trade-off to review | KRD path |
|---|---|---|---|---|
| Manual control | Simple, stable process with limited operating change | Operator setting | Does not automatically compensate for diameter, speed or process disturbance | Manual controllers |
| Open-loop calculation | Known unwind or rewind behaviour where an estimated output is practical | Diameter or radius estimate, material thickness, line speed, encoder or proximity signal, or programmed torque model | No direct measurement of actual web tension; the model and torque hardware must match the machine | KRD semi-automatic controllers |
| Closed-loop feedback | Changing diameter, speed or material sensitivity requires measured correction | Load-cell tension feedback or dancer-position feedback, where supported | Needs correct measuring geometry, calibration, tuning and controller-to-feedback compatibility | Automatic controllers |
Application Inputs
Prepare the evidence that changes the recommendation
A model number should come after the machine context. Record these five groups before requesting a final equipment direction.
Type, transparency, porosity, thickness, coating, surface and edge or print target.
Unwind, infeed, process, guide point, slitter, rewind or retrofit location.
Web width, line speed, tension range, roll diameter, acceleration and duty cycle.
Installation space, web path, mounting, PLC or fieldbus signals, power and safety constraints.
For web guiding
Add the guiding reference, allowed deviation, sensor position, correction point, required stroke and actuator mounting.
For tension control
Add the target tension, measuring-roller geometry, torque device, current controller and start-stop behaviour.
For retrofit projects
Add machine drawings, existing model numbers, photos of the installation area and the reason for replacement.
Next Technical Step
Use the detailed guides after choosing the path
Sensor comparison
Review material and mounting considerations in the ultrasonic versus photoelectric guide.
Control-loop comparison
Compare feedback logic, hardware and process implications for open and closed loops.
Actuator retrofit
Scope stroke, thrust, speed, feedback and mounting before choosing an actuator.
Application Review
Bring the machine data. KRD will help narrow the equipment direction.
Share the material, web width, speed, control zone, target, existing hardware and installation constraints. The first review should identify the system path before a final model is selected.