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Safety Light Curtains: 2026 Buyer’s & Selection Guide
Safety Light Curtain Buyer’s Guide: How to Choose the Right Model
Choosing a safety light curtain is not mainly a question of comparing catalog numbers. The right model depends on the hazard, what must be detected, the size of the opening, the distance across the machine, stopping performance and the way the protective device will be integrated into the safety function.
A useful buying process therefore starts with the application requirements and works toward the model, rather than starting with a supplier’s product table and trying to make the machine fit it.
This guide focuses on the decisions that normally determine whether a safety light curtain will actually fit the machine: safeguard type, resolution, protection height, sensing distance, response time, safety distance, environmental conditions and project documentation.
This guide helps you decide
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01Whether a safety light curtain is the right safeguard for the access pattern and hazard.
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02Which detection resolution and protection height the application actually requires.
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03How sensing distance, response time and machine stopping performance affect final model selection.
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04What to verify before ordering, including electrical interface, environment, certification scope and replacement compatibility.
Looking for current CCH product specifications rather than buying
methodology? See the
ENT Safety Light Curtain Series
.
02 · Start With the Safeguard
Is a Safety Light Curtain the Right Safeguard?
Before comparing models, first decide whether an electro-sensitive protective device fits the hazard and the way people interact with the machine.
Safety light curtains are especially useful where operators need frequent access through a defined machine opening and a fixed physical guard would interfere with the intended process. They can detect interruption of the protective field without requiring a door or mechanical barrier across the opening.
That does not make them the right safeguard for every hazard. A light curtain does not physically contain parts, tools, chips, sparks or process material that may leave the machine. It also depends on the machine being able to reach the required safe state before a person can reach the hazardous area.
Four Questions to Ask Before Selecting a Model
01
Can the hazardous motion be stopped in time?
If the hazard cannot be brought to the required safe state before a person could reach it, a safety light curtain may not provide sufficient protection on its own.
02
Does the process require frequent open access?
Light curtains are often valuable where operators repeatedly load, unload, position or remove parts and need unobstructed access to a defined opening.
03
Is physical containment also required?
If the machine can eject material, broken tools, hot particles or other hazardous objects, physical guarding may still be required even when presence sensing is also used.
04
Is the protection need a line or an area?
A light curtain creates a defined sensing plane. Where the application requires configurable two-dimensional floor or area protection, a safety laser scanner may be a better fit.
Compare the Safeguarding Concept Before the Product
| Safeguard | Often Considered When | Important Limitation |
|---|---|---|
| Safety Light Curtain | A defined opening requires frequent operator access and hazardous motion can be stopped before the person reaches the hazard. | Provides presence detection, not physical containment. |
| Fixed Guard | Routine access is not required and a physical barrier can prevent entry to the hazardous area. | Access for setup or maintenance requires a separate safe procedure or access arrangement. |
| Interlocked Guard | Physical containment is useful but operators also require controlled access through a door, gate or movable guard. | The interlocking system and machine stopping behavior must be designed for the required safety function. |
| Safety Laser Scanner | The application requires configurable two-dimensional area monitoring or floor-level protective fields. | Field geometry, environmental conditions and safeguard positioning require application-specific evaluation. |
A good buying decision starts by selecting the right safeguarding concept. Product comparison comes after that.
Buyer Note
Do not buy a light curtain only because another machine uses one.
Similar-looking machines can have different hazards, stopping performance and access patterns. Evaluate the actual application first. If your requirement is two-dimensional area protection, see the Safety Area Scanner Engineering Guide .
03 · Build the Specification
Six Things to Define Before You Choose a Safety Light Curtain
A model number should be the result of the selection process, not the starting point. Define these six requirements first and most product choices become much easier to compare.
Suppliers often receive enquiries such as “I need a 1,000 mm safety light curtain” or “Please quote a Type 4 model.” Those details are useful, but they are not enough to select the complete device.
A practical specification should combine the safety requirement, the geometry of the protective field and the electrical and environmental conditions of the machine.
01
Required Safety Performance
Start with the machine risk assessment and required safety function.
Determine what protective-device classification and overall
safety-related control performance the application requires.
Do not select Type 2 or Type 4 simply from machine size, price or
what another machine uses.
02
Detection Resolution
Define what must be detected when a person approaches the hazard.
Resolution represents the minimum object size the device is designed
to detect and can influence safeguard positioning.
Current CCH ENT options include 14, 25 and 45 mm, but resolution
should always be selected from the application requirement.
03
Protection Height
Measure the opening or access path that the protective field must
cover. Consider whether a person could reach above, below or around
the active sensing field.
Physical sensor length and effective protection height should not
be assumed to mean the same thing.
04
Sensing Distance
Measure the actual distance between transmitter and receiver in the
proposed installation. Check that the selected model supports that
operating distance with the planned mounting arrangement.
Do not choose the longest available range automatically; choose a
configuration that fits the real machine geometry.
05
Response Time & Safety Distance
The exact model response time contributes to the total time used in
safeguard-positioning calculations. Machine stopping performance and
approach conditions must also be known before final installation.
A faster light curtain does not remove the need to measure or
validate the machine stopping performance.
06
Environment & Electrical Interface
Confirm enclosure protection, temperature, water exposure, mounting
conditions, supply voltage, safety outputs, connector or cable
requirements and compatibility with the planned safety-related
control architecture.
IP rating, functional-safety Type and electrical interface are
separate specifications and should be checked independently.
Preparing an RFQ
What Information Should You Send the Supplier?
A useful safety light curtain enquiry can usually be prepared from a short set of machine data. Supplying this information early reduces unnecessary model changes later.
- Machine or equipment type
- Hazard location
- Required detection capability
- Required protection height
- Transmitter-to-receiver distance
- Available installation distance from the hazard
- Machine stopping information
- Required safety-related control interface
- Environmental conditions
- Replacement model, if applicable
The best quotation request describes the machine requirement first and the desired model second.
Buyer Note
A specification sheet is more useful than asking only for “the price
of a safety light curtain.”
Protection height and sensing distance may narrow the model family, but resolution, response time, safety performance and installation conditions still determine whether that model is appropriate for the machine.
04 · Size the Detection Field
Resolution and Protection Height: Two Specifications You Should Not Confuse
Resolution tells you what size of object the safety light curtain is designed to detect. Protection height tells you how much of the machine opening the active sensing field covers. Both matter, but they solve different selection problems.
Buyers sometimes start with a request such as “I need a 1,000 mm light curtain.” That describes part of the required protective-field size, but it does not tell the supplier whether the application requires finger-oriented, hand-oriented or wider-pitch detection.
The reverse is also true. Specifying a 14 mm safety light curtain does not define the required protection height. The application still needs enough active sensing coverage to address the opening and foreseeable ways a person could reach the hazard.
Resolution
Detection Capability
The minimum object size the safety light curtain is designed to detect under its specified operating conditions. Finer resolution allows smaller objects to be detected and can influence the required safeguard positioning.
Protection Height
Active Sensing Coverage
The effective height of the protective sensing field. It should cover the required access opening while the overall machine design prevents a person from bypassing the safeguard by reaching over, under or around it.
Using 14, 25 and 45 mm as a Real Product Example
Safety light curtains are available in different resolutions across the market. The current CCH ENT Type 4 platform uses 14, 25 and 45 mm detection-resolution families. These values are useful examples of how resolution changes the intended detection requirement; they are not a statement that all safety light curtains in the industry use only these three resolutions.
| CCH Platform | Resolution | Current Protection Height Range | Typical Selection Direction |
|---|---|---|---|
| ENT14 | 14 mm | 120–1000 mm | Fine detection where smaller-object or finger-oriented safeguarding is required. |
| ENT25 | 25 mm | 120–1720 mm | Medium-resolution machine guarding where hand-oriented detection is appropriate. |
| ENT45 | 45 mm | 120–1960 mm | Wider-pitch detection where the safeguarding design permits a larger minimum detectable object size. |
Before Requesting a Quote
Measure the Required Protective Field — Not Just the Housing
If you are replacing an existing safety light curtain, do not assume that two products with similar physical housing length provide the same active protection height. Use the existing device specification or measure the machine opening and confirm the required active sensing coverage.
The same applies when designing a new machine. Protection height should come from the safeguarding geometry, not simply from the nearest catalogue length.
Resolution answers “what must be detected?” Protection height answers “how much of the opening must be protected?”
Buyer Note
Do not choose resolution and protection height independently.
After defining both parameters, the selected model still needs to meet the required sensing distance and response-time conditions. For current CCH ENT model data, see the ENT Safety Light Curtain Series .
05 · Plan the Installation Distance
Safety Distance: Know It Before You Order
Safety distance affects where the light curtain can be installed and whether the selected model fits the machine layout. It should be considered during model selection, not left until commissioning.
A safety light curtain must be positioned so that hazardous machine motion can reach the required safe state before a person can reach the danger zone. ISO 13855:2024 provides the framework used to evaluate safeguard positioning relative to human approach.
For the buyer, the important point is that the required distance is not determined by one product specification alone. It depends on the selected model response time, the machine stopping performance, detection capability and the way a person can approach the hazard.
Light Curtain Response Time
Response time is model-dependent. Use the exact value for the
selected protection height and configuration rather than the fastest
value shown for the product family.
Machine Stopping Performance
The machine control system and hazardous motion require time to
respond and reach the required safe state after the protective
field is interrupted.
Detection Capability
Resolution affects how an approaching body part is detected and can
influence the safeguard-positioning requirements.
Approach Geometry
Reaching through, over, under or around a protective field can
require different considerations. The installation must address the
actual access path to the hazard.
Why This Matters Before You Choose the Model
Imagine that the available space between the machine opening and the hazard is limited. A model with a longer response time may increase the required separation distance enough that the intended mounting position no longer works.
In that case, simply ordering a light curtain based on resolution and protection height can create a problem later. The machine may need a different device configuration, a different mounting position, or changes to the stopping performance of the safety function.
Do Not Use a Generic Response Time
Many safety light curtain families contain models with different beam counts and protection heights. Response time can therefore vary across the same product family.
This is why the quotation or datasheet for the exact model matters. For the current CCH ENT platform, response time is model-dependent and should be checked before the final safety-distance calculation is made.
New Machine Projects
Use Safety Distance as a Layout Input
For a new machine, safeguard positioning should be considered early enough that the mechanical layout can accommodate the required distance. Leaving this decision until the electrical installation stage can lead to unnecessary redesign.
For replacement projects, do not assume the old mounting location is automatically acceptable for a different light curtain model. Recheck the response time, detection capability and complete stopping performance.
A light curtain that fits the opening but cannot be positioned at the required safety distance is not yet the right model for the machine.
Engineering Tool
Calculate with the actual machine and the actual model.
Use the ISO 13855:2024 Safety Distance Calculator as an engineering aid once you have the selected light-curtain response time and machine stopping information.
06 · Define the Required Device Type
Type 2 or Type 4? Start from the Required Safety Function
Type 2 and Type 4 are safety-device classifications defined within the IEC 61496 framework. They should not be treated as simple product tiers where one is merely the cheaper version and the other is automatically the correct choice for every machine.
The selection should begin with the machine risk assessment and the performance required from the complete safety function. That analysis then helps determine the appropriate electro-sensitive protective device and the rest of the safety-related control architecture.
It is also important not to reduce the decision to statements such as “Type 4 means PL e” or “Type 2 means PL c.” Device Type under IEC 61496 and the performance of the complete safety-related control function are related engineering considerations, but they are not interchangeable labels.
Start With
The actual machine hazard, foreseeable access, required risk
reduction and the safety function that must be achieved.
Then Determine
The protective-device Type, required control-system performance,
architecture and validation appropriate to that safety function.
Do Not Decide From
Machine size, purchase price, supplier preference or the assumption
that a device with a more demanding classification automatically
makes the complete machine safety function adequate.
What If Your Current Specification Simply Says “Type 4”?
That is a useful starting requirement, but it is still not a complete purchasing specification. The buyer must also define the required resolution, protection height, sensing distance, response time, environmental conditions and interface requirements.
Two Type 4 safety light curtains can therefore both meet the requested device classification while being very different choices for the same machine.
Common Buying Mistake
“Higher Type” Does Not Replace Application Engineering
Selecting Type 4 simply because it appears to offer a more demanding device classification does not remove the need to assess detection capability, safety distance, bypass possibilities, machine stopping performance and the complete safety function.
Choose the required safety function first. The device Type follows from that engineering decision — not from a product price ladder.
Related Engineering Guide
Need a deeper Type 2 vs Type 4 comparison?
Read the Type 2 vs Type 4: Risk-Based Selection Guide for the detailed comparison, or see the Type 4 Safety Light Curtain Guide for IEC 61496, resolution and safeguard-positioning context.
07 · Review the Complete Project
Before You Buy: Compare the Complete Project, Not Just the Sensor
Two safety light curtains can appear similar in a quotation while creating very different installation, integration and replacement requirements. Compare the exact project configuration, not only the purchase price or headline specifications.
By the time resolution, protection height and sensing distance are defined, the list of possible models is usually much shorter. The next step is to verify that the exact model can be integrated into the machine and supported by the required technical documentation.
This is especially important for machine builders and replacement projects, where a small difference in response time, mounting, electrical interface or certificate coverage can affect the overall safeguarding design.
01
Exact Model Datasheet
Verify the specification for the exact model being purchased,
including resolution, protection height, sensing distance, response
time, electrical data and environmental limits. Do not rely only on
a family-level marketing page.
02
Certificate Scope
Check which product family, model designation and standard scope are
actually covered by the available certification documentation.
Functional-safety certification and EMC documentation should not be
treated as the same thing.
03
Response Time
Use the response time of the exact selected model when evaluating
safeguard positioning. A product family can contain different
response times depending on protection height and beam count.
04
Cable, Connector & Mounting
Confirm cable arrangement, connector requirements, mounting space,
bracket position and mechanical access before purchase. A correct
sensing specification can still create installation work if these
details are overlooked.
05
Safety Control Integration
Confirm how the safety outputs will be monitored by the machine’s
safety-related control system. The protective device must be
integrated as part of the complete safety function rather than
treated as an isolated stop device.
06
Environmental Conditions
Compare the actual installation environment with the specified IP
rating, operating temperature, ambient-light immunity and other
relevant environmental limits.
07
Replacement Compatibility
For replacement work, compare more than physical length. Check
resolution, active protection height, response time, output behavior,
wiring, mounting position and the assumptions used in the original
safety function.
08
Technical Documentation
Confirm that the project has access to the required datasheet,
operating instructions, wiring information and applicable
certification documentation before installation and validation of
the complete safeguarding function.
Comparing Quotations
Do Not Compare Only the First Line of the Quote
A lower unit price does not automatically mean a lower project cost. The useful comparison is whether each proposed model actually satisfies the same application requirement.
| Compare | Why It Matters |
|---|---|
| Detection Resolution | Affects what the protective field is intended to detect and can influence safeguard positioning. |
| Protection Height | Determines whether the active sensing field covers the required machine opening. |
| Sensing Distance | Must fit the actual transmitter-to-receiver spacing of the installation. |
| Response Time | Contributes to the total stopping time considered when determining safeguard position. |
| Environmental Rating | Determines whether the device specification matches the actual installation conditions. |
| Electrical Interface | Must be compatible with the intended safety-related control architecture and machine wiring. |
| Documentation | Supports engineering review, installation, commissioning and validation of the selected device. |
Replacement Projects
“Same Size” Does Not Mean “Drop-In Replacement”
Replacing an existing safety light curtain requires more than finding a housing with similar dimensions. Differences in resolution, protection height, response time, wiring or mounting can change the assumptions behind the original safeguarding design.
Record the existing model number and available machine documentation first, then compare the proposed replacement against the complete application requirement.
The lowest sensor price is only useful when the selected device still fits the complete safeguarding project.
Buyer Note
Ask for the exact model documentation before final approval.
If you are evaluating the current CCH ENT platform, start with the Safety Light Curtain Series and confirm the exact model specification required by your machine.
08 · Buyer FAQ & Further Reading
Safety Light Curtain Buyer’s Guide FAQ
The final model should come from the machine application, not from one headline specification. These are some of the questions worth resolving before a purchase is approved.
What information do I need before requesting a safety light curtain quote?
At minimum, define the machine application, required detection capability, protection height, transmitter-to-receiver distance, available safeguard position, machine stopping information, environmental conditions and the required safety-control interface. A current or replacement model number is also useful when available.
What safety light curtain resolution should I choose?
Resolution should be selected according to what the protective device must detect and the safeguarding arrangement. Finer resolution can detect smaller objects and may affect safeguard positioning. The current CCH ENT platform includes 14, 25 and 45 mm resolution families.
Is protection height the same as the physical length of the light curtain?
Not necessarily. Protection height refers to the active sensing coverage, while the physical housing also includes mechanical and optical structure outside that active field. Use the protection height specified for the exact model rather than assuming it from the overall housing length.
How far should a safety light curtain be installed from the hazard?
There is no universal fixed distance. Safeguard positioning depends on factors including the exact device response time, machine stopping performance, detection capability and approach geometry. The applicable calculation should be made for the actual machine using the relevant requirements of ISO 13855:2024 .
Does a safety light curtain stop the machine by itself?
No. The light curtain detects interruption of its protective field and changes the state of its safety outputs. Those outputs must be integrated into a complete safety-related control function that brings the hazardous machine motion to the required safe state.
Should I always choose a Type 4 safety light curtain?
Not simply because Type 4 appears to be a more demanding device classification. The machine risk assessment and required safety function should determine the appropriate protective-device Type and safety-related control architecture. See the Type 2 vs Type 4 risk-based selection guide for the detailed comparison.
Does IP65 mean a safety light curtain is suitable for any wet environment?
No. IP65 describes specific ingress-protection test conditions and should not be interpreted as a general claim for immersion, severe washdown, chemical exposure or outdoor suitability. The current CCH ENT safety light curtain platform is specified as IP65. For more detail, see the Waterproof Safety Light Curtain and IP Rating Guide .
Can I replace an old safety light curtain with another model of the same size?
Similar physical dimensions do not establish functional compatibility. Compare resolution, active protection height, response time, sensing distance, electrical interface, mounting and the assumptions used in the existing safety function before treating another device as a replacement.
Standards Referenced
Engineering Standards Behind the Selection Process
Product selection, risk assessment, safety-control performance and safeguard positioning are covered by different standards. They should be used together where applicable rather than treated as interchangeable classifications.
IEC 61496-1:2020
General requirements and tests for electro-sensitive protective
equipment.
IEC official publication →
IEC 61496-2:2020
Particular requirements for active opto-electronic protective
devices such as safety light curtains.
IEC official publication →
ISO 12100:2010
General principles for machinery design, risk assessment and risk
reduction.
ISO official publication →
ISO 13849-1:2023
Design principles for safety-related parts of machine control
systems.
ISO official publication →
ISO 13855:2024
Safeguard positioning with respect to the approach of the human
body.
ISO official publication →
This guide is intended to support product-selection discussions. Final safeguard selection, positioning and integration should be based on the actual machine risk assessment, applicable standards and the exact device documentation used in the project. The completed safety function should then be validated for the machine application.