Packaging film · Wire · Tube · Profile · Feed the length, cut on cue — set from the panel · Multi-spec one-key changeover · No PLC, no programming · Changeover in minutes
Constant-length feeding is the classic single-axis process: feed the material to the set length → stop → signal the cutter → cut → feed again, cycle after cycle. The traditional approach uses a PLC to pulse the feeder and program the cutter timing — the machine is simple, yet development is not: programming, wiring and commissioning all still apply.
This solution is built around the SD6 integrated drive & control closed-loop stepper driver: the feeding length, speed and accel/decel for different products are stored as multi-segment parameters. A start signal (button or sensor) triggers the move; at length, the programmable IO automatically outputs the cutter signal; once "cut complete" returns, the next cycle starts. No PLC anywhere, and not a single line of code — at product changeover the operator presses two keys on the panel and edits one number.
Closed-loop encoder feedback keeps the fed length exactly where it was commanded — no drift over long runs — while stall detection senses jammed material instantly: when the material jams, the system knows by itself.
Sensors and buttons connect straight to the driver IO; the feeding logic closes its loop inside the driver — the host PC only appears when parameters are edited
Changeovers are everyday life in film, wire and tube converting. This solution stores common specs as multi-segment parameters — each segment independently sets the feeding length, speed and accel/decel time. To change products, recall the segment on the panel. No program, ever.
| Segment | Length (mm) | Speed (mm/s) | Accel/Decel | Example Spec |
|---|---|---|---|---|
| Seg 1 | 150 | 180 | Medium | Small roll · short spec |
| Seg 2 | 300 | 220 | Medium | Standard spec |
| Seg 3 | 500 | 160 | Slow | Long spec (slow profile prevents lost steps) |
| Seg 4 | 800 | 120 | Slow | Extra-long spec |
Example values; segment count and values depend on the driver spec and process. Changeover = recall a segment, done in under a minute
At feeding length, the programmable IO automatically outputs the cutter signal; after the "cut complete" feedback returns, the next cycle begins. For the process detail of material retraction at the cut, a micro-compensation travel can be reserved in the cutting segment — length deviation is corrected directly on the panel: edit the number, and the next piece is on target. No program involved.
| Signal | Direction | Function |
|---|---|---|
| Cycle start | DI input | Triggers the active feeding segment (button / foot switch / upstream interlock) |
| Cycle stop | DI input | Finishes the current segment then stops (dedicated e-stop terminal separate) |
| Origin switch | DI input | Power-up homing, re-establishes the length datum |
| ± Limit switches | DI inputs | Hard travel protection — stops and alarms on trigger |
| Cut complete | DI input | Cutter feedback, confirms before the next cycle |
| Cutter output | DO output | Drives the cutter (solenoid / relay) at feeding length |
| Run / alarm | DO output | Indicator and buzzer; stall (jammed material) alarms automatically |
Point count and terminal definitions per SD6 specification; input active level NO/NC selectable
| Item | Traditional (PLC + driver) | SD6 Constant-Length Solution |
|---|---|---|
| Control devices | PLC + pulse output + driver | One SD6 only |
| Spec change | Ask the vendor to modify PLC program | Panel segment recall, one-minute changeover |
| Length accuracy | Open-loop pulses, error needs program compensation | Closed-loop feedback — no drift over time |
| Development | Programming + commissioning, measured in days | Fill the parameter table, measured in hours |
| Jam awareness | Extra sensors + program logic required | Stall detection alarms automatically |
| Troubleshooting | PLC or driver? Check both | Driver status LEDs + software, one-step location |
Accuracy comes from closed-loop feedback plus the mechanical transmission: the closed-loop encoder guarantees the commanded steps are truly made; actual length deviation mostly comes from material slip and cutter action. Keep the pinch roller properly loaded and add a timing compensation for the cutter. Typical film/wire duty easily meets ±0.5 mm class requirements — verify on your actual material.
No. With multi-segment parameters stored, operators recall a segment on the panel. Adding a new spec is just editing one length number — no program, no vendor dependency.
Yes. The original PLC pulse output connects directly to the SD6 pulse interface — a drop-in replacement with minimal rework; afterwards you gain multi-segment presets and stall detection, and Modbus RTU can be enabled later for line integration.
Optionally add Modbus RTU with a touchscreen: parameters are pushed to multiple drivers centrally and statuses monitored in one place. Changeover happens on the screen. Standalone production is unaffected if the touchscreen goes offline.
Parameters are filled in the office; on site there is only wiring, trial cutting and training
| Question | Answer |
|---|---|
| 1. Is your process a "constant-length feed ± cut/label" single-axis operation? | Yes / No |
| 2. Do you change specs frequently and want vendor-independent changeover? | Yes / No |
| 3. Do you lack a dedicated electrical engineer and prefer programming-free commissioning? | Yes / No |
| 4. Do you have multi-axis interpolated linkage or complex line interlocks? (If "yes", use a PLC solution) | Yes / No |
Items 1–3 "yes" and item 4 "no": this solution applies directly. Send us your motion sequence for a free analysis if unsure.