SICK / Safety light curtains

A forklift usually only hits one end. The sender and receiver are separate parts, so replacing a damaged curtain is often a single item rather than a pair.

SICK light curtains guard presses, palletisers, conveyor exits and robot cells across New Zealand. deTec4 is current; C4000, M4000, FGS and MSL are still everywhere.

Reading the model designation

Take deTec4 Core Set 30/1650.

So a deTec4 Set 30/900 is a 30 mm resolution curtain covering 900 mm.

The word Set is doing work. Without it you may be looking at a single half.

Both numbers are safety-critical

Neither can be substituted freely, and for different reasons.

Resolution decides what the curtain detects

The coarser the resolution, the further back the curtain has to be mounted. The minimum safety distance calculation in ISO 13855 takes the resolution, the machine stopping time and an approach speed.

So fitting a 30 mm curtain where a 14 mm one was, in the same brackets, gives you a working curtain and inadequate guarding. The hardware will not complain.

Protective field height decides what it covers

Straightforward but worth stating: a shorter curtain leaves a gap. Someone can reach over or under.

If the exact height is unavailable, that is a design question rather than a substitution. Do not fit a shorter one and move on.

Sender and receiver

The practical heart of this page.

Tell us which half. The sender is the transmitter and the receiver carries the OSSD outputs and the diagnostics, so they are different parts at different prices.

If the label is unreadable, the receiver is the end with the cable carrying the safety outputs and usually the status display.

Matched pairs

Sender and receiver must be the same family, resolution and height. A deTec4 sender does not work with a C4000 receiver, and a 30 mm sender does not pair with a 14 mm receiver.

When buying used, buy the pair from one source if you need both.

What a Set does not include

SICK states for the deTec4 Core kits: the cabling and safety relay are sold separately.

So a curtain arriving on site is not a working installation. Tell us what you already have and we will quote the gaps rather than duplicating what is on the shelf.

The families

FGS to deTec4

SICK positions deTec4 as the replacement for FGS.

It is not a drop-in. Different housing, different mounting, different connections. An FGS replacement is either a like-for-like used unit or a planned changeover.

On a machine with a documented safety assessment, a used FGS of the same resolution and height keeps the assessment intact, where a deTec4 means revisiting it. That is often the deciding factor rather than the part price.

M4000 is not a curtain

A multi-beam device cannot be used for hazardous point protection, and a curtain cannot practically span 90 m. They solve different problems and are not alternatives.

M4000 carries a 7-segment diagnostic display and the EFI interface for device communication. SICK also lists an adapter for connecting an M4000 to MSL terminal compartments, which is useful on a legacy changeover.

Ratings

Type 2 and Type 4 are not interchangeable. A Type 2 device has lower fault detection and cannot be used where a Type 4 was specified.

SICK's LiDAR multibeam scanner for automated guided carts, for example, is Type 2, PL c, SIL 1, which suits a moving vehicle and does not suit a press.

Blanking and muting

These decide the model, not just the settings.

Muting needs more than the curtain

Muting is on every palletiser and conveyor exit in the country, and it is a system rather than a feature.

A curtain without muting support cannot be made to mute. If a machine passes product through the field, the model has to have it, and a cheaper model of the same resolution and height will not do.

If a muting installation is nuisance-tripping, the muting sensors are the usual cause rather than the curtain. Alignment drifts, and the sequence timing is what the system checks.

OSSD outputs, and why they upset PLC inputs

Light curtains switch through OSSD outputs, typically two for redundancy.

OSSDs are pulsed. They test themselves continuously by dropping the output for microseconds at a time.

That is why an OSSD goes to a safety relay or safety input, not a standard PLC input. A standard input may see the test pulses as real transitions and read intermittently.

If someone has wired a curtain straight into a standard input and it flickers, the curtain is fine.

Environment versions

Note the stainless version is limited to 4.5 m. If the opening is wider, stainless is not an option and the answer is a different guarding approach.

In a New Zealand meat or dairy washdown area, a standard housing will corrode and the failure will look like a curtain fault.

Mirror columns

Used to fold a single curtain around two or three sides of a cell rather than buying multiple pairs.

SICK publishes mirror columns with protective field height mirrors and 125 mm mirror width.

Each mirror costs you range. A curtain rated for a given scanning distance loses a proportion at every reflection, so a two-mirror installation needs a curtain rated well beyond the straight-line distance.

Same principle as the Pilz PSENopt mirror columns on our Pilz page, where the mirror must also be longer than the protective field.

What to send us

The full type designation. Family, variant, resolution and height.

The SICK part number, printed on the label alongside the type.

Sender, receiver, or both.

Whether the installation uses muting or blanking.

Whether you need cables, brackets or a safety relay, since none come with a Set.

A photo of the end cap if the label has faded.

Important: safety replacements

Light curtains are certified as part of a machine's safety function, and the mounting distance was calculated from the resolution.

A like-for-like replacement of the same type preserves the assessment. A different resolution or height does not.

We will supply exactly what you specify. If you ask for an alternative we will say what we believe is equivalent and what differs, but the decision belongs with whoever is responsible for the machine's safety. We are a parts supplier, not your safety engineer.

What we can supply

Current production. deTec4 and deTec4 Core, miniTwin, plus cables, brackets, mirror columns, muting sensors and lamps. Quoted with a delivered lead time.

Discontinued. C4000 across all variants, M4000, FGS and MSL. Surplus and tested used, which keeps an existing installation exactly as assessed.

Single halves. Senders and receivers separately.

Accessories. The cables, brackets and muting hardware that a Set does not include.

We buy SICK light curtains

C4000, M4000 and FGS hold real value to plants still running them, because a like-for-like replacement avoids a safety reassessment.

Keep senders and receivers together. A matched pair is worth considerably more than two orphaned halves. See Sell To Us.

Related

SICK overview.

For light curtains from other brands see Pilz PSENopt, Omron F3S, ABB Jokab Focus and Allen-Bradley Guardmaster.

Send us your type designations

Include the resolution and height, and tell us which half you need. A forklift rarely hits both. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with SICK AG. SICK, deTec and miniTwin are trademarks of SICK AG. All trademarks, brand names and part numbers are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute a safety assessment.