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CCH ENT Series · Machine Safeguarding
ENT Type 4 Safety Light Curtain for Machine Guarding
CCH ENT Series safety light curtains provide Type 4 electro-sensitive protection for hazardous machine openings, points of operation and access areas. Choose from 14, 25 and 45 mm detection-resolution platforms, with model-dependent protection heights and sensing distances for different machine-guarding requirements.
Type 4 · IEC 61496
Cat. 4 · ISO 13849
PL e
SIL 3 · IEC 61508
IP65
ENT Series at a Glance
Detection Resolution
14 / 25 / 45 mm
Protection Height
Up to 1960 mm
Current Range Codes
A / B / C
Safety Output
2 × OSSD
Output Configuration
PNP / NPN
Enclosure Protection
IP65
Selection note:
Type 4, Cat. 4, PL e and SIL 3 describe different aspects of
functional-safety performance and should not be treated as interchangeable
labels. Final machine safety performance depends on the complete safety
function, machine risk assessment and correct integration.
02
Understanding Type 4
What Is a Type 4 Safety Light Curtain?
A Type 4 safety light curtain is an active opto-electronic protective device designed for machine safeguarding under the IEC 61496 framework. Type 4 devices use extensive internal diagnostics and fault-monitoring measures so that faults relevant to the safety function are detected with a high level of reliability.
01
High Diagnostic Coverage
Type 4 architecture includes continuous monitoring and diagnostic measures intended to detect faults that could otherwise impair the protective function.
02
Designed for Demanding Safety Functions
Type 4 safety light curtains are commonly used where the machine risk assessment requires a high level of safeguarding performance and an opto-electronic protective device is appropriate.
03
Part of a Complete Safety System
The light curtain is only one element of the safety function. Safety outputs, control logic, stopping performance, installation distance and machine architecture must also be correctly designed.
CCH ENT Series
Type 4
Cat. 4 · PL e · SIL 3 capability
ENT Is Built for Type 4 Machine Safeguarding
The CCH ENT platform is designed and certified as a Type 4 safety light curtain platform. Depending on the complete safety architecture, it can be integrated into safety functions requiring high levels of risk reduction, including applications designed up to Cat. 4 / PL e and SIL 3 capability.
Type 4 does not automatically mean every machine requires Type 4.
The required safety performance should come from the machine risk assessment and applicable standards. Resolution, safety distance, stopping time, control architecture and the complete safety function still need to be evaluated for the specific application.
03
ENT Resolution Platforms
Choose ENT14, ENT25 or ENT45 by Detection Requirement
Safety light curtain resolution defines the minimum object size the sensing field is designed to detect. The CCH ENT series provides 14, 25 and 45 mm platforms for different machine-guarding requirements. Resolution should be selected together with protection height, installation geometry and safety distance.
Fine Resolution
ENT14
14 mm
Finger-Oriented Detection
Designed for applications requiring detection of smaller objects within the protective field, including safeguarding near machine points of operation where fine detection capability is required.
Detection Resolution
14 mm
Protection Height
120–1000 mm
Response Time
8.3–30.8 ms
Medium Resolution
ENT25
25 mm
Hand-Oriented Detection
A medium-resolution platform for machine guarding where the application requires a balance between detectable object size, protection height and installation conditions.
Detection Resolution
25 mm
Protection Height
120–1720 mm
Response Time
6.8–27.2 ms
Wider Resolution
ENT45
45 mm
Access-Oriented Detection
The widest-resolution ENT platform, supporting taller protective fields for applications where the safeguarding design permits a larger minimum detectable object size.
Detection Resolution
45 mm
Protection Height
120–1960 mm
Response Time
6.0–17.8 ms
Resolution Is Not the Same as Risk Level
A 14 mm model is not automatically a “higher safety” choice than a 25 or 45 mm model. The required safety performance comes from the machine risk assessment, while resolution defines the required detection capability.
Resolution and Safety Distance Work Together
Detection capability affects safeguard positioning, but final safety distance also depends on machine stopping performance, protective-device response time and the applicable approach conditions.
First select what must be detected — then select the complete ENT model.
After choosing 14, 25 or 45 mm, confirm the required protection height, sensing distance and model-specific response time before completing the safety-distance evaluation.
04
Core ENT Features
Safety Outputs, Synchronization & Configuration
The ENT platform combines Type 4 safeguarding with practical configuration and diagnostic functions for industrial machine integration. The exact configuration should always be confirmed for the selected ENT model and application.
01
Dual OSSD Safety Outputs
ENT provides two OSSD safety outputs for connection to an appropriate safety-related machine control system. The outputs must be integrated and validated as part of the complete machine safety function.
02
PNP / NPN Configurable Output
The ENT platform supports configurable PNP or NPN output logic, allowing the electrical interface to be matched to different machine-control requirements.
03
Optical Synchronization
Transmitter and receiver synchronization is handled optically, helping simplify installation without requiring a separate synchronization cable between the two light curtain units.
04
CH-A / CH-B Channel Selection
Channel selection helps manage installations where multiple safety light curtains operate near each other and optical interference must be considered.
05
LONG / SHORT Range Configuration
Sensing-distance configuration allows the system to be adapted to the required installation range while supporting stable transmitter-to-receiver operation.
06
Infrared Configuration & Status Indication
Infrared configuration functions and visible status indication support setup, operating-state confirmation and troubleshooting during installation and maintenance.
Machine Safety Interface
2 × OSSD
Safety-related switching outputs for integration with the
machine safety control system.
The Light Curtain Is One Part of the Safety Function
OSSD signals must be integrated into an appropriate safety-related control architecture so that interruption of the protected field leads to the required safe machine response. The final safety function depends on the complete control system, machine stopping performance and validated installation.
Configure the ENT for the machine — not the other way around.
Output logic, operating range, channel selection and other settings should be established from the electrical design and installation conditions. Safety-related settings should be verified during commissioning and after changes to the machine or protective system.
05
Advanced Guarding Configurations
Flexible Safety Light Curtain Configurations
Some machines require more than one simple straight protective field. Depending on the selected ENT model and safeguarding design, cascading, floating blanking and optical redirection can support more complex machine layouts.
Multiple Protective Fields
Cascading
Cascading allows compatible safety light curtain units to be combined where more than one protective field is required around the same machine or safeguarded area.
Typical design direction
Multiple machine openings, interconnected protective fields and
guarding arrangements requiring more than one sensing zone.
Protective-Field Configuration
Floating Blanking
Where supported by the selected ENT configuration, floating blanking allows a defined number of beams to be interrupted while the permitted interruption position can move within the protective field.
Typical design direction
Applications in which a defined moving machine element or process
object must occupy part of the sensing field as part of the
validated safeguarding concept.
Multi-Side Protection
Reflective-Column / Multi-Side Guarding
Suitable reflective or optical-redirection arrangements can extend the protective path around more than one side of a machine where the installation geometry and available optical operating margin allow it.
Typical design direction
L-shaped or multi-side guarding around machine areas where a
straight transmitter-to-receiver field is not sufficient.
Blanking Changes Detection Capability
Enabling blanking changes the effective behavior of the protective field. The resulting detection capability and required safeguard positioning must therefore be evaluated for the configured application.
Optical Redirection Affects the Installation
Mirrors or reflective-column arrangements increase the optical path and make alignment more demanding. Sensing distance and available operating margin should be checked for the complete optical route.
Safety Function Design
Configuration Must Follow the Risk Assessment
Advanced Functions Require Application-Specific Validation
Cascading, blanking and multi-side guarding can provide useful design flexibility, but they do not reduce the need for correct safety distance, protection against bypassing the sensing field, appropriate safety-control integration and validation of the complete machine safety function.
Confirm advanced functions for the exact ENT model before final design.
Availability and permitted configuration can depend on the selected model and application. Use the applicable technical documentation when configuring blanking, cascading or a multi-side optical arrangement.
06
Machine-Guarding Applications
Typical Applications for Type 4 Safety Light Curtains
ENT Type 4 safety light curtains can be used in a wide range of machine-guarding applications where an opto-electronic protective device is appropriate. The final configuration should be selected from the machine risk assessment, required detection capability, access geometry and stopping performance.
01
Press Machines
Safety light curtains are commonly used to protect access to hazardous press working areas where operators load, position or remove parts. Resolution and installation distance should match the actual point-of- operation safeguarding requirement.
Point-of-Operation Guarding
02
Hydraulic & Forming Equipment
Hydraulic presses, forming equipment and similar machinery may require access protection around hazardous moving tools or work areas. The machine stopping performance is especially important when determining light-curtain positioning.
Hazardous Motion
03
Robot Cells
A safety light curtain can protect defined entry points to a robot cell where physical guarding alone would restrict material flow or operator access. The complete cell safety architecture must still control hazardous robot motion.
Access Protection
04
Automated Production Lines
Automated assembly, handling and production systems often contain operator access points that require safeguarding without permanently closing the machine opening.
Automated Machinery
05
Assembly & Handling Stations
Light curtains can be used where operators repeatedly reach into a machine or handling station and physical guards would interfere with the intended production cycle.
Repetitive Access
06
Machine Access Openings
Safety light curtains can protect openings used for loading, unloading or process access when interruption of the sensing field can be integrated into an appropriate safe machine response.
Opening Protection
Application Does Not Determine Resolution by Itself
A press machine is not automatically an ENT14 application, and a robot cell is not automatically an ENT45 application. Select the resolution from what must be detected and how a person can approach the hazard.
Stopping Performance Still Controls Positioning
Even when the correct Type and resolution have been selected, the protective device must be positioned so that hazardous motion can reach a safe state before a person can reach the danger zone.
Application Support
Selecting ENT for a Specific Machine?
Tell us the machine type, hazard location, required protection height, installation distance and detection requirement. CCH can help narrow the ENT configuration before final safety-system validation.
07
Functional Safety & Certification
Type 4 Functional Safety and Verified Product Compliance
Certification should be read together with the product specification and the complete machine safety design. For the ENT platform, functional-safety evaluation and electromagnetic-compatibility verification address different aspects of product performance.
Functional Safety
SGS-TÜV Saar Certification
The ENT safety light curtain platform is supported by functional-safety certification documentation from SGS-TÜV Saar for the applicable certified configuration. The certification establishes the evaluated product scope and safety-performance characteristics defined in the certificate.
Electromagnetic Compatibility
TÜV Rheinland EMC Verification
EMC testing and certification address electromagnetic immunity and emissions-related product requirements. EMC compliance is important for reliable industrial operation, but it should not be confused with functional-safety certification.
AOPD Classification
Type 4
Category Capability
Cat. 4
Performance Level
PL e
Safety Integrity
SIL 3
Important Distinction
Certified Device ≠ Certified Machine
Product certification supports machine safety design,
but does not replace machine-level validation.
Final Safety Performance Depends on the Complete Safety Function
Installing a Type 4 safety light curtain does not automatically make the complete machine Cat. 4, PL e or SIL 3. Safety-related control logic, output devices, stopping performance, wiring, diagnostic coverage, safety distance and validation must all support the required machine safety function.
Check the Model Scope
Confirm that the selected ENT model and configuration are included within the applicable certification documentation.
Check the Required Standard
Machine-specific standards or local regulations may introduce requirements beyond the safety light curtain’s own product certification.
Validate the Final Installation
Verify wiring, safety outputs, stopping behavior, positioning and protective coverage before the machine enters operation.
Use the certificate itself when exact compliance scope matters.
Reference the official IEC standards catalogue and ISO standards catalogue when confirming the current applicable standard editions.
Website summaries are useful for product selection, but the applicable certificate and technical documentation should be used to verify the exact standards, model scope and certified conditions required for a customer project.
08
Technical Specifications
ENT Series Technical Data
Use these specifications for initial ENT platform selection. Protection height, beam count, response time and available sensing-distance configuration vary by model, so the selected model datasheet should be checked before final engineering approval or ordering.
ENT14 / ENT25 / ENT45 Platform Comparison
| Parameter | ENT14 | ENT25 | ENT45 |
|---|---|---|---|
| Detection Resolution | 14 mm | 25 mm | 45 mm |
| Beam Spacing | 10 mm | 20 mm | 40 mm |
| Protection Height | 120–1000 mm | 120–1720 mm | 120–1960 mm |
| Response Time | 8.3–30.8 ms | 6.8–27.2 ms | 6.0–17.8 ms |
| Maximum Beam Count | 101 | 87 | 50 |
| Typical Selection Direction | Fine detection / finger-oriented safeguarding | Medium resolution / hand-oriented safeguarding | Wider resolution / access-oriented detection |
Common ENT Platform Specifications
Safety Performance
ESPE Type
Type 4 · IEC 61496
Category
Cat. 4
Performance Level
PL e
Safety Integrity Level
SIL 3
PFH
1.42 × 10⁻⁸
Diagnostic Coverage
>99%
Optical Performance
Light Source
Infrared LED · 850 nm
Resolution
14 / 25 / 45 mm
Synchronization
Optical
Optical Channels
CH-A / CH-B
Range Mode
LONG / SHORT
Protection Height
Up to 1960 mm
Electrical & Output
Operating Voltage
24 V DC ±20%
Emitter Current
<200 mA
Receiver Current
<200 mA · no load
Safety Output
2 × OSSD
Output Type
PNP / NPN configurable
Maximum Output Load
≤100 mA / output
Startup Time
<3 s
Environmental & Mechanical
Protection Rating
IP65
Profile Size
34 × 28 mm
Operating Temperature
−10°C to +55°C
Storage Temperature
−40°C to +70°C
Operating Humidity
35–85% RH
Incandescent / Fluorescent Light
3,000 lux
Sunlight Immunity
10,000 lux
Current Sensing-Distance Configurations
ENT Range Codes
RANGE CODE A
0–10 m
RANGE CODE B
0–16 m
RANGE CODE C
0–5 m
Available range codes are model-dependent. For applications outside
the currently listed ranges, confirm the available configuration with
CCH Engineering rather than assuming a longer sensing distance.
Use the exact model response time when calculating safety distance.
The ENT response-time range across the current platform is model-dependent. Safety distance should never be calculated from a generic or minimum response-time value. Use the actual selected model together with the complete machine stopping time and the applicable safeguarding methodology.
09
ENT Selection Guide
How to Select the Right ENT Safety Light Curtain
Select the ENT configuration from the safeguarding requirement rather than from one specification alone. Detection resolution, protection height, sensing distance, response time and final safety distance should be evaluated in sequence.
01
Choose Resolution
Select 14, 25 or 45 mm according to what must be detected and how a person can approach the hazard.
02
Define Protection Height
Cover the required machine opening while considering possible access above, below or around the protective field.
03
Confirm Sensing Distance
Match the actual transmitter-to-receiver distance to a supported range configuration for the selected model.
04
Check Response Time
Use the exact model response time because it contributes to the total time used in safeguard-positioning calculations.
05
Determine Safety Distance
Calculate the required position from the machine stopping performance, device response and applicable approach conditions.
Selection Principle
Select the Complete Model
Resolution Alone Is Not Enough
ENT models with the same detection resolution can differ in protection height, beam count, response time and available sensing distance. Final selection should therefore use the complete model specification and actual machine conditions.
Replacing an Existing Safety Light Curtain
Compare detection capability, protected height, response time, sensing distance, mounting and electrical interface. A physically similar light curtain should not automatically be treated as a drop-in safety replacement.
Designing a New Machine
Define the safeguarding concept early so that machine layout, stopping performance and available installation distance can be coordinated with the selected protective device.
10
Safety Distance
Safety Distance for Type 4 Safety Light Curtains
A Type 4 safety light curtain must be installed far enough from the hazardous area that the machine can reach the required safe state before a person can reach the hazard. ISO 13855:2024 provides the framework used to evaluate safeguard positioning relative to human approach.
01
Machine Stopping Performance
The calculation must include the time required for the complete safety function and hazardous machine motion to respond and reach the required safe state.
02
Light Curtain Response Time
ENT response time varies by model and beam count. Use the exact response time of the selected ENT configuration rather than a generic minimum value.
03
Detection & Approach Geometry
Detection capability and the way a person can approach, reach over, reach under or otherwise access the hazard can affect the required safeguard positioning.
ENT Model Selection
Response Time Is Model-Dependent
ENT14, ENT25 and ENT45 do not use one universal response-time value.
Select the Exact ENT Model Before Finalizing Safety Distance
Protection height and beam count affect the response time of the selected ENT configuration. For final safety-distance evaluation, use the actual model response time together with the total machine stopping performance and the applicable approach conditions.
Do not copy a safety-distance value from another machine.
Even two machines using the same safety light curtain can require different installation distances because stopping performance, approach geometry and the complete safety-related control system may be different. Safety distance should be calculated and validated for the actual machine.
Use the ISO 13855:2024 Safety Distance Calculator
Enter the actual machine stopping information and selected light-curtain parameters to evaluate the applicable separation distance. The calculator is an engineering aid and does not replace machine-specific risk assessment or final validation.
11
Frequently Asked Questions
Type 4 Safety Light Curtain FAQ
These questions cover the most common issues when selecting and integrating an ENT Type 4 safety light curtain for industrial machine guarding.
What is the difference between a Type 2 and Type 4 safety light curtain?
Type 2 and Type 4 are classifications for active opto-electronic protective devices under the IEC 61496 framework. They differ in areas such as fault-detection and diagnostic requirements. The required device type should be selected from the machine risk assessment and required safety performance rather than from price or application name alone. See our Type 2 vs Type 4 selection guide .
Which ENT resolution should I choose: 14 mm, 25 mm or 45 mm?
ENT14 provides 14 mm detection resolution and is typically evaluated for finger-oriented protection. ENT25 provides 25 mm resolution for many hand-oriented safeguarding applications. ENT45 provides 45 mm resolution for access-oriented or larger-object detection. Final selection depends on what must be detected, approach geometry and the required safety distance.
What is the maximum sensing distance of the ENT safety light curtain?
Current ENT configurations use model-dependent range codes including A at 0–10 m, B at 0–16 m and C at 0–5 m. Not every resolution, protection height and range combination should be assumed to be available, so confirm the exact model specification before ordering.
Is the ENT Type 4 safety light curtain IP65?
Yes. The ENT platform has an IP65 enclosure rating. IP65 describes environmental protection against dust ingress and water jets under the applicable test conditions. It is separate from the Type 4 functional-safety classification.
What are OSSD outputs on a safety light curtain?
OSSD outputs are safety-related switching outputs used to communicate the protective-device status to an appropriate machine safety control system. ENT provides two OSSD channels. Their integration must form part of the complete safety-related control architecture.
Does ENT support PNP and NPN outputs?
The ENT platform supports configurable PNP or NPN output logic. The required electrical configuration should be confirmed for the selected model and matched to the machine safety-control interface.
Can ENT Type 4 safety light curtains be used on press machines?
They can be evaluated for press and forming-machine safeguarding where an opto-electronic protective device is appropriate. The final solution depends on the machine risk assessment, point-of-operation geometry, stopping performance, required detection capability and applicable machine standards.
Can a Type 4 safety light curtain be used for robot-cell access protection?
Yes, a Type 4 safety light curtain can form part of a robot-cell safeguarding system when the risk assessment and cell design support that protective concept. The light curtain must be integrated with the robot and machine safety controls so that entry into the protected area produces the required safe response.
Can ENT replace an existing safety light curtain from another manufacturer?
A replacement may be possible, but it should not be treated as an automatic drop-in substitution. Compare detection resolution, protection height, sensing distance, response time, mounting, electrical interface, safety outputs and the required safety performance before approving the replacement.
How do I calculate the safety distance for an ENT light curtain?
Use the actual ENT model response time together with the total machine stopping performance, detection capability and applicable approach conditions. Safety distance must be determined for the actual machine, not copied from another installation. Use our ISO 13855:2024 Safety Distance Calculator as an engineering aid.
Still unsure which ENT configuration fits your machine?
Start with the hazard location, required detection capability, protection height, transmitter-to-receiver distance and machine stopping information. These inputs make model selection much more reliable than choosing from resolution or sensing distance alone.
12
Engineering Resources
ENT Resources, Documentation & Project Support
Use current product specifications and machine-specific engineering information when selecting and integrating an ENT Type 4 safety light curtain.
Product Selection
ENT Safety Light Curtain Series
Review current ENT14, ENT25 and ENT45 configurations, including resolution, protection height, sensing distance and response-time information.
View ENT Series →
Safety Engineering
Type 2 vs Type 4 Selection Guide
Learn how protective-device Type relates to risk assessment, diagnostic requirements and the performance required from the complete machine safety function.
Read the Engineering Guide →
Engineering Tool
ISO 13855:2024 Safety Distance Calculator
Evaluate safeguard positioning using the selected light-curtain response time, machine stopping information and applicable approach conditions.
Open Safety Distance Calculator →
OEM / Private Label
OEM Safety Light Curtain Projects
For qualified projects, CCH can support private-label product presentation and selected customization such as branding, labels, cable or connector options, housing color, packaging and customer-branded documentation.
Explore OEM / ODM Support →
Before Final Approval
Verify the Exact ENT Model
Use the Applicable Technical Documentation
Confirm the complete model code and use the corresponding current technical documents before ordering or approving the machine design. Where certification scope is important, verify the selected model against the applicable certificate documentation.
CCH Engineering Support
Need Help Selecting a Type 4 Safety Light Curtain?
Send us the machine type, hazard location, required detection capability, protection height, sensing distance and stopping information. We can help narrow the appropriate ENT configuration for your project.
Final risk assessment, safety-system design and validation should
be completed for the actual machine and application.