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Safety for Packaging
Safety Light Curtains for Packaging Machines — TÜV Type 4 / Cat.4 / PL e / SIL 3
Safety light curtain for packaging lines withstanding its muting in current pallet flow- engineered for palletizers, stretch wrappers, case packers and cartoners. Rated Category 4 ESPE per IEC 61496-1,2: 2020 with 14/25/45 mm resolution, detection ranges to 70 m, and a dedicated SRB safety relay module integrating muting, reset and restart into one Cat.4/ PL e signal chain.
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Why Packaging Lines Need Purpose-Built Safety Light Curtains
Machine guarding (291 CFR 1910.212) related violations caused 1,541 OSHA citations in 2014, placing them in the Top 10 Most Cited Violations – and packaging machinery remains a common culprit as trays, pallets, cartons and totes pass cross through guarded zones in full view of the operators. As material flow increases in automated plants, injury-related injuries in material handling and automated packaging lines are mounting, and the risk is focused towards the access points through which the work flows. Physical barrier guards block the flow, simple photoelectric sensors cannot provide the 4 Category requirements to prevent injury, and when a line trips the incident quickly costs the plant floor. estimated American production in $25,000 in 2014 around Siemens’ True Cost of Downtime 2014 indicates that unplanned downtime averages approximately per hour for mid-sized manufacturers and approximately 27 hours of manufacturing downtime per month for the largest manufacturers.
A safety light curtain is a presence-sensing safety device – an adjacent array of infrared beams forming an invisible barrier across the hazardous area. When a finger, hand, or body crosses the presence of this light curtain, they register a safe shutdown command to the machine controller within milliseconds. It does not slow line changeover like a physical guard door; it does not need the floor to be dry and tack-free like a safety mat; and it tolerates the vibration of a well running conveyor like sticky and adhesive residue. For a line running 18+ hours per day, a light curtain product remains the only presence sensor able to meet both Category 4 /PL e safety and throughput realities in automation today.
What separates a packaging application from a press brake or a robot cell is the controlled material bypass.
Pallets must leave the palletizer; stretch-wrapped loads must leave the wrapper; filled cartons leaving the case packer must index out of the machine. A light curtain has to stay energized at the operators’ station while simultaneously flash-fusing for product, and it must do both without interruption at line speed. This is the muting problem—and it is the exact place where many implementations in the field crash and burn. One r/PLC operator described a name-brand curtain being tested on a palletizer infeed where “it turns off right away after it comes on,” which causes the wrapper to drop out faulted several times per shift. Muting reliability is not a brand issue; it is a system design issue. That is why the ENT product line comes equipped with a dedicated SRB-2A1B safety relay featuring the following inputs: MUT_H /MUT_L; dual-channel PNP/NPN monitoring; two A/B optical communication channels preventing cross-talk between adjacent light curtains on the same line.
Below is a walkthrough of the CCH ENT offer, the application environment in which it performs, the hard facts which support Type 4 certification and the purchasing conditions which enable a Chinese-made light curtain to rival the European brands your plant has experience of. Industrial automation and materials handling decisions are a question of efficiency; investing in the right safety system means reduced risk of injury, higher machine availability and the speed the control system expects.
Product Line
CCH ENT Series — Packaging-Grade Safety Light Curtain Product Range
Three finger / hand / body resolution classes Five detection distance ranges Cascading-ready housing A matching SRB safety relay module for muting, reset and restart logic. Every model delivered TV-certified to Type 4 / Cat.4 / PL e / SIL 3. We have built ENT as a family that sits alongside with our safety laser scanner and solid state lidar sensor technologies they make up a full perimeter, zone and point-of-operation protection stack for packaging machinery.
ENT-14 mm
Finger Protection
Optical axis spacings 10 mm, detection tolerances 14 mm. Designed for close point-of-operation access for case erectors, cartoning and high speed filling machines where a finger needs to push in to trip the machine stoppage.
Réglé à: 6.0 – 30.8 ms
Max plage: 0 – 70 m
Max plage: 0 – 70 m
ENT-25 mm
Hand Protection
Optical axis: 20mm, detection accuracy: 25mm. Dominant sensor for the pouch palletizer infeed, stretch wrapper entry zones and bagger access points. Works well with the 4-sensor parallel muting on the pallet outfeed.
Réponse: 6.0 – 30.8 ms
Gamme: 0 – 70 m
Gamme: 0 – 70 m
ENT-45 mm
Body / Perimeter Protection
Optical axis spacing 40mm, detection accuracy 45mm. Robotic cell perimeter plus end-of-line conveyor guarding large palletizingzones that they are applies body wide intrusion detection what OSHA and ANSI B11.19 seeking for.
Réponse: 6.0–30.8 ms
Plage Max: 0–70 m
Plage Max: 0–70 m
Technical Parameters
| Parameter | ENT-14 mm | ENT-25 mm | ENT-45 mm |
|---|---|---|---|
| Optical axis spacing | 10 mm | 20 mm | 40 mm |
| Detection accuracy | 14 mm (finger) | 25 mm (hand) | 45 mm (body) |
| Detection distance ranges | A: 0 – 10 m · B: 0 – 16 m · C: 0 – 5 m · D: 0 – 40 m · E: 0 – 70 m | ||
| Protection height | up to 1,960 mm (cascadable to perimeter) | ||
| Response time | 6.0 – 30.8 ms (scales with beam count) | ||
| Operating voltage | 24 V DC ±20 % | ||
| Safety output | Dual PNP or dual NPN (field-selectable via IR remote or mobile APP) | ||
| IP rating | IP65 | ||
| Operating temperature | –10 °C to +55 °C (no condensation) | ||
| Ambient light immunity | Incandescent 3,000 lx · Fluorescent 3,000 lx · Sunlight 10,000 lx | ||
| Vibration / shock | 10 – 55 Hz, 0.35 mm amplitude · 10 g shock, 16 ms pulse | ||
| Diagnostic coverage | > 99 % with real-time self-test every < 10 min | ||
| Housing | 34 × 28 mm cross-section, aluminum, cascading adapter optional | ||
| Mounting options | ZC front/side · CX magnetic · GZ pipe · TC T-slot · FZ with protective cover | ||
“The dual A/B optical channel split was a direct response to the field complaint we heard most often on palletizer installations – adjacent curtains on the same cell triggering each other during pallet index. Its infrared source splits across two frequency bands so two curtains can be mounted within half a metre and not talk to each other. It was not on the original ENT spec; the packaging OEMs asked for it.”
ENT Selection Decision Matrix
Use this matrix to shortlist a model range before requesting a full quotation. Every recommendation is a jumping-off point – the final choice depends on the risk assessment, safety distance calculation per ISO 13855 and the architecture of the safety controller on your line.
| Application | Recommended resolution | Distance range | Muting / Cascading |
|---|---|---|---|
| Palletizer infeed / outfeed | ENT-25 mm (hand) | B: 0 – 16 m | 4-sensor parallel muting + SRB relay |
| Robotic palletizing cell perimeter | ENT-45 mm (body) | D: 0 – 40 m | Cascaded segments, no muting on perimeter |
| Stretch wrapper entry | ENT-25 mm or ENT-45 mm | A: 0 – 10 m | T-configuration muting for load pass-through |
| Case packer / cartoner access | ENT-14 mm (finger) | C: 0 – 5 m | Fixed blanking for static carton guides |
| High-speed filling & sealing | ENT-14 mm | A: 0 – 10 m | No muting; cycle-based reset via SRB |
Comparison
Safety Light Curtain vs Physical Guards vs Safety Mats — A Data-Driven Comparison
The three presence-sensing and guarding technologies that dominate machine safety on packaging lines each earn their keep in different conditions. Packaging wins the light curtain case on throughput and changeover speed; the other two still have their place.
| Evaluation dimension | Safety light curtain (ENT series) | Physical guard / fence | Safety mat |
|---|---|---|---|
| Type 4 compliance path | Direct: IEC 61496-1,2 Type 4 + ISO 13849-1 PL e | Via interlock switch (dual-channel) | Cat.3 PL d typical; Cat.4 requires careful layout |
| Changeover impact | Clear access — 0 seconds lost to opening a gate | 30 – 90 seconds per gate cycle (interlocked) | Mat lifts / restores — 10 – 25 seconds |
| Footprint loss per access point | ~80 mm depth (post + curtain) | 400 – 800 mm (panel + door swing) | Mat area equal to body zone (≥ 900 × 900 mm) |
| Material bypass (product flow) | Muting function holds safe state for product, shuts down for personnel | Separate open slot required; often non-compliant | Cannot distinguish product from operator |
| Environmental durability | IP65; 10,000 lx sunlight immunity; –10 to +55 °C | Mechanical — immune to light & EMI | Degrades under adhesive / shrink residue; wet floor risk |
| Response time | 6.0 – 30.8 ms | Interlock < 20 ms + gate travel | 20 – 50 ms typical |
| Maintenance (annual) | Alignment check & lens wipe; no wear parts | Hinge, latch, interlock actuator wear | Membrane wear; replace every 3 – 5 years |
| Best fit on packaging lines | Primary choice for palletizer, wrapper, case packer, cartoner access | Perimeter fencing around robot cells; complementary to curtain | Limited — operator platforms, fixed hazardous area floor coverage |
TCO framing
If an access point sees 12 changeovers per shift, a 60-second gate cycle loses 72 minutes of production per 3-shift day. At the Siemens 2024 downtime benchmark of roughly $25,000 per hour for a mid-sized plant, that is on the order of $30,000 of production time per access point per month. A Type 4 light curtain pays for itself in weeks on any line that changes SKU more than once a shift. This comparison is rarely “curtain versus fence” – it is usually “curtain and fence,” with the light curtain owning the access points where personnel and product both move, and the physical guard owning the perimeter where neither do.
Packaging Applications
Packaging Application Solutions — Palletizer, Stretch Wrapper, Case Packer, Cartoner
Four end-of-line scenarios, four muting strategies, one relay module. Every layout below has been pulled from real ENT deployments and written against the specific failure modes discussed in public automation forums.
Robotic Palletizer — Infeed & Outfeed Muting
The pain
Public PLC forum threads document name-brand safety light curtains on palletizer exits where the muting “turns off right away after it comes on,” leaving a downstream wrapper faulted out several times per shift. Root failure mode is usually muting-sensor sequencing – the cross-beam on the pallet outfeed drops before the main curtain clears, and the safety relay interprets it as an intrusion.
Root cause
Single-frequency light curtains on adjacent cell edges also suffer optical cross-talk when a pallet reflects infrared between the infeed and outfeed sensors – the two curtains are within a metre of each other and they end up seeing each other’s light.
Our ENT solution
ENT-25mm (hand resolution) on both infeed and outfeed mounted at 0 – 16 m range with 2 sets of optical frequency channels (A / B) which completely prevent cross-talk interference between the 2 curtains. Muting itself is controlled via the SRB-2A1B safety relay utilizing the MUT_H /MUT_L inputs via a four sensor parallel muting grid comprised of two photoelectric sensors positioned above and below the pallet passes position ensuring they cannot be caused to be muted during the muting sequence in an unsafe condition. Output contacts are fed Category 4 / PL e directly into the machine safety controller. This dedicated muting reset line is connected to the operator’s pendant so a recovery cycle does not require the restart of the entire palletizer.
Stretch Wrapper — Load Pass-Through with Fixed Blanking
The pain
Rotary and arm-style wrappers have rotating machine parts protruding into the guarding zone during each revolution. A light curtain that acknowledges the movement of the rotating arm as an intrusion causes the wrapper to fail every revolution- encouraging operators to bypass the safety device, which is most often how most stretch wrapper accidents occur.
Our ENT solution
ENT-45 mm (body protection with the first N beams blanked) set up as a fixed masking zone over the envelope of the rotating arm. Only the predetermined obstruction is ignored and any hand, shoulder or torso intrusion crossing the remaining beams triggers the devices safety function. T-configuration muting is active only for the case load pass-through window. Its automatic reset mode ensures continued indexing of the wrapper for production, while any spurious intrusion immediately stops the turntable.
Case Packer & Cartoner — High-Speed Finger Protection
The pain
Case erectors and cartoners operate at 30-80 cpm with moving flaps, glue guns and compression plates. Operators frequently place their hands in areas liable for jams. At these operating speeds; a response greater than 30 ms is inadequate to halt the cycle before a finger is trapped- and a manual reset after a safe stop cannot create a lost line index.
Our ENT solution
ENT-14mm (finger protection) with a 0-5 m range covering the case feed access window, with the relay configured for a manual reset via a dedicated machine-side reset switch. A 6.0 ms minimum response time on the shortest beam arrays accommodates the stop-time calculation for the majority of servo-driven cartoners. Fixed blanking masks hide the stationary carton profile so the curtain remains armed against obstruction hazards but are not nagged by false signals.
End-of-Line Conveyor & Filler / Sealer Zones
Long conveyor guards, filler carousels and cappers are best protected with cascaded ENT segments. That ENT cascading adaptor allows multiple emitter-receiver pairs to be linked onto a single safety output, so a 30 m conveyor protected by 4 cascaded ENT-45 mm segments appears as a single Category 4 signal chain to the machine controller. Maintenance and replacement are a station-by-station task and not a complete rewiring of the entire safety loop- a definite advantage for plants that would prefer not to shut production down during a light curtain fault.
Certifications & Compliance
Certifications & Global Standards Compliance
All ENT safety light curtains and SRB-2A1B safety relays are type approved by the German authorities (TV) to the highest level of performance ever required in electro-sensitive protective equipment. Standard type 4 light curtains (along with the entire safety system derived from them) can ensure dependable hand and body protection in any industrial environment where the output signal switching device is required to monitor a zone of access. Certification stack corresponds directly with the standards your safety engineer will be referencing:
ESPE Type
Type 4
IEC 61496-1,2:2020
Safety Category
Cat. 4
ISO 13849-1:2023
Performance Level
PL e
ISO 13849-1:2023
SIL
SIL 3
IEC 61508
Protection
IP65
Ingress Class
Tested by
TÜV
Third-Party Verified
Global Safety Standards Cross-Reference
| Region | Standard | Scope |
|---|---|---|
| International | IEC 61496-1,2:2020 | Electro-sensitive protective equipment (ESPE) — Type 4 classification |
| International | ISO 13849-1:2023 / -2:2012 | Safety of machinery — functional safety, Category 4, PL e |
| International | IEC 61508-1 to -4:2020 | Functional safety of E/E/PE systems — SIL 3 |
| International | IEC 62061 | Machinery safety — SIL for safety control systems (SRB relay) |
| Europe | EN IEC 61496-1,2:2020 | Harmonised European equivalent for Type 4 ESPE compliance |
| United States | OSHA 29 CFR 1910.212 | Machine guarding general requirement (the most-cited U.S. rule in packaging) |
| United States | ANSI B11.19 | Performance criteria for safeguarding — presence-sensing devices |
| China | GB 4584 | Safety light curtain equivalent national standard |
Guide de Achats Public
Procurement Guide — Pricing Factors, Lead Time, Customization & Free Samples
What is interesting is never the sticker price of a safety light curtain? What matters is the entire landed cost into your plant, the integration time with your present safety controller and then can this brand indeed bring a sample in for Qualification before you invest the capital?
Pricing Factors Framework
All of your ENT quotesshared the same building blocks.Understanding the drivers allowed your procurement team to pre-qualify the scope before issuing a formal RFQ, and enabled you to automate the shortlist against your standard sourcing template:
Protection height (beams)
Controls the optical array length and scales directly with the cost of materials and calibration.
Resolution class
ENT-14/25/45mm have different emitter densities and diagnostic loops: the thinner the resolution class, the more expensive per millimetre of protection height.
Range of detection separation
Five ranges (A to E) correspond to the seven infrared driver power categories 0 70 mE-range being the top category.
Method of mounting & accessories
ZC, CX magnetic, GZ pipe, TC T-s lot and FZ protecting-cover kits all are equipped with their own accessory bill.
Cascading & SRB relay config
Single-segment curtains are shipped separately. Cascaded or muting enabled systems includes the cascading adapter and the SRB-2A1B relay.
Quantity tier & OEM customization
Normal SKUs ship in stock, custom housing, protection height in between standard steps or private label branding shifts into OEM.
Lead Time, MOQ & Customization
Standard ENT stock SKUs are typically shipped on short lead time from Hangzhou factory; accelerated air freight is available for prototype volumes. OEM custom-ization – non-standard protection heights, private-label housings, application-tailored muting logic, integration test report – is performed by the same engineering group that maintains the ENT design baseline. MOQ for stock SKUs is flexible for qualification order; please talk to our quotations desk for your current project window.
Free Test Sample Program
We ship free qualification samples to importers, system integrators and packaging OEMs who need to run their own bench test before committing to a production order. This is the cheapest de-risking step in the entire procurement cycle — you put a physical ENT on your test bench, run it against your own PLC and stop-time measurement, and make the buy decision from real data rather than a data sheet. Very few European safety sensor brands offer this; it is one of the clearest structural advantages of working directly with a manufacturer instead of a distributor.
Chinese Manufacturer vs European Brand — Decision Matrix
| Evaluation axis | CCH ENT (direct manufacturer) | Tier-1 European brand (via distributor) |
|---|---|---|
| Type 4 certification | TÜV type-tested, full EN IEC 61496-1,2:2020 + ISO 13849-1:2023 compliance | Equivalent — same standards apply |
| Landed unit cost | Direct manufacturer pricing, no distributor markup | Distributor-marked, higher unit cost |
| Lead time to prototype | Stock SKUs air-freight quickly; custom OEM aligned to project schedule | Distributor stock varies; custom routed through regional HQ |
| Free qualification sample | Yes — part of the standard workflow | Rarely offered at distributor level |
| Engineering support | Direct line to the R&D team that designed ENT and SRB — including muting layout review | Front-line distributor then application engineer escalation |
| Brand recognition on plant floor | Newer name in the US/EU market; gains acceptance through sample qualification and cert audit | Already familiar to existing maintenance teams |
| OEM / private label | Supported — housing colour, branding, spec tweaks handled in-house | Rare at distributor level; usually refused or slow |
Engineering Resources
Packaging Safety Engineering Tools
Utilize our precision calculators to determine the exact safety distance and optimal light curtain sizing for your packaging machinery setup, ensuring strict compliance with ISO 13855 and OSHA standards.
ENT Safety Light Curtain Sizing Selector
Input your machine’s protection height and resolution requirements to instantly generate the correct ENT series SKU, compatible relay modules, and mounting hardware configuration.
Launch SelectorSafety Light Curtain Distance Calculator
Calculate the minimum safe mounting distance based on stopping time, operator approach speed, and sensor response time. Ensure your installation strictly adheres to ISO 13855 equations.
Launch CalculatorReady to specify a safety light curtain for your packaging line?
“Send us the machine, the protection height, and the muting or cascading requirement. Our engineers will get back to you within 24 hours with a recommended ENT SKU, the compliance documentation package, and a free test sample if desired.”
Frequently Asked Questions
Yes. OSHA 29 CFR 1910.212(a)(1) accepts presence-sensing devices as a valid form of machine guarding when they interrupt the machine cycle before a worker can reach a hazardous area. A Type 4 safety light curtain conforming to IEC 61496-1,2 is one of the specifically named technologies in OSHA’s presence-sensing guidance. What matters is that the stop-time calculation (ANSI B11.19 / ISO 13855) has to confirm the curtain halts motion before any body part can reach the hazard — which is why resolution, response time and safety distance matter as much as the certification itself.
Muting is the controlled, time-limited suspension of the light curtain’s protective function to let product cross the guarded zone without tripping the machine. On a palletizer outfeed it usually involves two or four auxiliary photoelectric muting sensors arranged in parallel, T or L configuration. Muting sensors must be positioned so that a person cannot replicate the muting pattern by walking through, and the mute window must close as soon as the pallet has cleared the curtain. On ENT installations muting is managed by the SRB-2A1B safety relay using the MUT_H / MUT_L inputs; the relay handles sequencing and timeout logic, and every mute event is logged by the relay status indicators for diagnostic follow-up.
In most cases, yes. Since the ENT outputs are field-selectable between dual PNP and dual NPN, and the SRB-2A1B relay monitors either signal format, integration with existing Siemens, Rockwell, Omron and Mitsubishi safety controllers is straightforward. Protection height classes align with the 30 mm / 500 – 1800 mm standard ranges used by the Tier-1 brands, and mounting brackets can be adapted via the CX, GZ or TC mounting kits. Most common retrofit work is cable pinout re-wiring and the stop-time recalculation — both of which our engineering team walks through before shipping a replacement sample.
Our ENT series outputs Type 4 compliant dual-channel PNP or NPN safety signals that can feed either a discrete-wired safety relay (the SRB-2A1B is the factory-matched option) or any third-party safety controller that accepts dual-channel OSSD inputs — Rockwell Guardmaster, Siemens Siguard, Pilz PNOZ, Omron G9SP and similar platforms all work. Output mode is switched via the infrared configuration remote or the mobile APP, so the same curtain can be commissioned on different control architectures without a hardware change. For muting, manual reset and restart logic the SRB-2A1B handles everything in a single DIN-rail module.
Response time determines how far a light curtain must be mounted from the nearest hazard — the safety distance formula in ISO 13855 ties stop performance directly to the intrusion detection time. Shorter response times let you mount the curtain closer to the machine, which saves floor space and operator walking distance. ENT response time runs from 6.0 ms on the shortest beam arrays up to 30.8 ms on the longest, including the diagnostic self-test overhead — competitive with every Tier-1 Type 4 curtain on the market and faster than many when configured for finger protection.
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