Double End Detector — Detects double ends, shells and lids

IS231

Self-calibrating detection of double ends at up to 800 ends per minute.

The Innosen IS231 Double End Detector is a self-calibrating sensor that protects seamers, end presses and end feeds from double ends. It detects double ends at up to 800 ends per minute, with a 3 millisecond response. It learns the correct end thickness from the first end that passes, so no operator ever adjusts it — not at a size change, not at a material change, not at a restart. And it signals the PLC on every single end it inspects, so the line always knows the sensor is watching.

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Innosen IS231 Double End Detector sensor for seamers and can end production lines.

The problem

Double ends wreck seamers and reach the customer

A double end entering a seamer is one of the most expensive faults on a canmaking line. The chuck and the seaming rolls are set for one end. Two ends together overload the tooling, and the damage is rarely confined to the end that caused it. Canmakers classify a double end as a serious container defect, because a can closed with two ends stacked together does not seam reliably — torn flanges, droops and vees follow.

In fact, doubles form in ordinary, unavoidable ways. Ends are stacked, bagged and fed in columns, and two lightly oiled shells cling together far more readily than two flat sheets do. Compound, lacquer and ordinary handling all make it more likely, and nothing about a double end looks wrong from the outside.

Changeover

It calibrates itself on the first end

The sensor takes its reference from the first end that passes. It then compares every end after that against the reference and, if the end falls within acceptable limits, uses it to fine-tune the setting — so the calibration tracks production rather than drifting away from it.

As a result, there are no buttons. No dials. No control box. No thickness programme to teach. Nothing an operator can set wrongly, because there is nothing an operator can set.

Diagnostics

A heartbeat on every end, so the line knows it is alive

Yet this is what most double end detectors cannot tell you. A sensor that has quietly failed is worse than no sensor at all, because the line still trusts it.

The IS231 produces a heartbeat output on every end it inspects — good or bad, every single one. The PLC can watch that signal as a watchdog: ends are passing, and the sensor is seeing them. If the heartbeat stops while the line is running, something is wrong and you know immediately. In addition, built-in self-diagnostics warn you the moment the detector develops a fault, and they can stop the line for you. A missing heartbeat is how the line learns that the sensor has reached the end of its life, that a cable has been cut or unplugged, or that a head has been knocked out of alignment — on the very next end, not hours later at the next manual check.

That is what makes ‘fit and forget’ a design principle rather than a gamble.

Fail-safe

Retrospective reject catches a double first end

A self-calibrating sensor has one theoretical weakness: if the first end it ever sees is itself a double, it could calibrate on the wrong thickness and pass the whole batch. However, the IS231 handles exactly this case.

When the second end arrives, it reads as half the thickness of the first. The sensor recognizes the error, and both outputs go high together — a signal the control system can use to stop the line so the offending ends are removed and the batch restarted. Innosen calls this retrospective reject: the sensor reaches back and rejects an end it has already passed.

Installation

Fits at the seamer, the press and the end feed

Seamer infeed — the primary position. Stop a double end before it reaches the chuck and the seaming rolls.
End press feed — protect press tooling from two shells entering the die together.
End destacker or magazine feed — catch doubles lifted out of the stack before they enter the machine.
Anywhere on the seaming line — the sensor only needs the ends to pass between its two heads.

Integration

No controller, no counter, no extra boxes

None of them. The sensor body holds all the electronics — the IS231 is a self-contained pair of sensing heads with industry-standard PNP outputs that wire straight into the line control system. The only thing ever set by hand is the gap between the two heads, once, at installation — and the sensor’s own status LED tells the fitter when the distance is right.

And because the heartbeat fires on every end inspected, the IS231 doubles as an accurate end counter. That is a second job it does for free, and one external counter you do not have to buy.

Double sheets

The same sensor also detects double sheets

The IS231 is one sensor with two applications. Fitted to a sheet line instead of an end line, it detects double sheets and blanks at up to 200 sheets per minute — at the unloader, the coater, the wicket oven or the slitter infeed. No separate product, no different part number. Each sensor does one job at a time — ends or sheets — so a plant that needs both fits one at each point.

See the IS231 Double Sheet Detector →

Response

3 ms — four per cent of the gap at 800 ends per minute

For example, at 800 ends per minute, one end passes every 75 milliseconds. The IS231 reaches its decision in the first 3 — about four per cent of the gap. At the slower speeds of a press or destacker feed, the decision takes a smaller fraction still.

That is why the sensor keeps up with a canmaking line rather than becoming the thing that limits it.

Rugged stainless steel forms the sensing heads, the electronics sit fully encapsulated, and the unit is sealed against vibration, humidity, EMI, fungus, hydraulic fluid and dust. There are no moving parts and nothing for an operator to mis-set. Most users commission an IS231 and never think about it again.

Features

Features
Self-Calibrating on the First End – the sensor takes its reference from the first end that passes, then compares every end after it against that reference and uses it to fine-tune the setting, so calibration tracks production instead of drifting away from it.
No Operator Adjustment at Changeover – no buttons, no dials, no control box and no thickness programme to teach.
Heartbeat Output on Every End – the sensor signals the control system on every end it inspects, good or bad, so the line can confirm the sensor is still working rather than trusting a silent one.
Retrospective Double Detection – if the very first end is itself a double, the second end reads as half its thickness. Both outputs go high together, so the control system can stop the line, the ends are removed and the batch restarted.
Accurate End Counting Included – because the heartbeat fires on every end inspected, the IS231 doubles as an end counter – one external counter you do not have to buy.
Self-Contained, No Control Box – the sensor body holds all the electronics, and industry-standard PNP outputs wire straight into the line control system.
Rugged Stainless Steel Heads – stainless steel forms the sensing heads, the electronics sit fully encapsulated, and the unit shrugs off vibration, humidity, EMI, fungus and hydraulic fluid.

Technical Specifications

Specifications	Value
End / sheet thickness	0.08 – 0.49 mm (0.0031″ – 0.019″), thin configuration 0.5 – 1.6 mm (0.020″ – 0.063″), thick configuration
Response time	3 ms (thin configuration) 6 ms (thick configuration)
Maximum speed — ends	800 per minute (contact Innosen for higher speeds)
Maximum speed — sheets	200 per minute
Output	Opto-isolated PNP, source, 20 mA current limit
Output pulse duration	Configurable: 10, 45 (default), 90 or 180 ms
Supply voltage	24 V DC ±10%
Supply current	130 mA typical (plus load)
Protection	Short circuit, reverse polarity, EMI
Operating temperature	0 °C to 45 °C (32 °F to 113 °F)
Storage temperature	−40 °C to 85 °C (−40 °F to 185 °F)
Sensor head	100 mm (4″) × ⌀30 mm (1.2″), M30 × 1.5 thread
Working distance	~45 mm nominal
Cables	2 m standard, screened, vibration-proof connectors. Other lengths available.
Environment	Sealed against vibration, humidity, EMI, fungus, hydraulic fluid and dust
Part number	395-45700-98

Media

Customer Testimonial

“We use Innosen double sheet/end sensors on multiple machines. They have made a big difference to our productivity and product quality. Delays and costs from coatings issues and machine damage from double sheets have been significantly reduced. We would not run the line without them.”

Rebice

Quality Manager, Orgaz, Spain

Frequently Asked Questions

What end thicknesses can the IS231 handle?

The IS231 is supplied in two configurations. The thin configuration covers 0.08 to 0.49 mm (0.0031″ to 0.019″) and the thick configuration covers 0.5 to 1.6 mm (0.020″ to 0.063″). Both self-calibrate on the first end that passes, so nobody has to enter or teach a thickness value.

Which types of end does the IS231 detect?

It works on easy-open ends, beverage ends, penny lever ends, sanitary ends and irregular ends, in aluminum, tinplate and tin-free steel. The sensor measures thickness rather than shape, so the end profile never has to be programmed in.

What line speeds does the IS231 support?

Up to 800 ends per minute as standard, with a 3 millisecond response in the thin configuration. At 800 ends per minute one end passes every 75 milliseconds, so the decision takes about four per cent of the available gap. Contact Innosen for higher speeds.

Where on an end line is the IS231 fitted?

The seamer infeed is the primary position, because a double end reaching the chuck and the seaming rolls is the most expensive failure. It is also fitted at the end press feed and at the end destacker or magazine feed, and it works anywhere on the seaming line where the ends pass between its two sensing heads.

What happens if the very first end is a double?

The sensor calibrates on the first end it sees, so a double first end would set the wrong reference. The IS231 handles this. The second end reads as half the thickness of the first, both outputs go high together, and the control system can stop the line so the offending ends are removed and the batch restarted. Innosen calls this retrospective reject.

Can the IS231 replace a separate end counter?

Yes. The heartbeat output fires on every end inspected, so the same signal that tells the control system the sensor is alive also gives an accurate end count. That removes one external counter from the line.

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