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Industrial Lift & Vertical Transfer Safety
Safety Light Curtains for Industrial Lifts and Vertical Transfer Equipment
Protect access openings around material lifts, vertical conveyors and automated transfer equipment where operators may be exposed to crushing, shearing or trapping hazards.
In appliance factories, assembly lines, warehouses and automated material-handling systems, products often move between different heights or floors through a vertical transfer unit.
A safety light curtain can be used to monitor an accessible opening and provide a protective signal to the machine safety system when a person enters the safeguarded area.
The correct solution depends on the hazard, opening geometry, access direction, stopping behavior and required safety architecture of the complete machine.
Appliance Manufacturing
Refrigerators, washing machines, air-conditioning units and large
assemblies moving between process levels.
Pallet Transfer
Vertical transfer of pallets, containers or workpieces between
conveyors.
Automated Lines
Access protection around automated production and material-handling
equipment.
Multi-Level Transfer
Upper and lower loading or unloading openings that require
system-level safeguarding.
Safety Engineering Note
A safety light curtain is one element of the safeguarding function, not the complete safety system. The required performance, mounting position, safety distance, control architecture, stopping behavior and restart logic should be determined through the machine risk assessment and validated for the complete application.
02 · Hazard Locations
Where the Hazard Occurs Around Industrial Lifts
The most important question is not where a light curtain can be mounted, but where a person can reach or enter a hazardous part of the vertical transfer system.
Industrial lifts and vertical transfer units often connect conveyors, workstations or production levels through one or more accessible openings. Depending on the machine design, a person may be exposed to moving platforms, loads, chains, belts, transfer mechanisms or the closing gap between moving and fixed structures.
The safeguarding concept should therefore begin with the hazardous movement and possible access path, then determine whether a safety light curtain, fixed guard, interlocked guard, safety laser scanner or a combination of measures is appropriate.
01
Lower Loading Opening
The lower level is often where operators, conveyors or automated handling equipment load a product onto the lift platform. If the opening is accessible while hazardous vertical or transfer movement can occur, personnel may enter or reach into the moving equipment.
Typical concerns:
access to moving platform, crushing zone, transfer mechanism or load.
02
Upper Unloading Opening
At the upper level, the lift may discharge a product onto another conveyor or workstation. An accessible opening can expose personnel to the moving platform, product transfer sequence or a fall/open-shaft hazard depending on the machine construction.
Typical concerns:
crushing, shearing, access to lift travel area and open transfer zone.
03
Conveyor Transfer Opening
A vertical lift is often integrated directly with powered conveyors. The opening may therefore contain several hazards at the same time: conveyor motion, lift motion and the transfer of the product between two moving systems.
Typical concerns:
drawing-in, trapping, conveyor access and transfer-point movement.
04
Side or Rear Access
Protecting the main loading opening does not automatically prevent access from the side or rear of the equipment. Gaps in perimeter guarding, adjacent walkways or open machine layouts can create bypass routes around a front-mounted light curtain.
Typical concerns:
bypassing the protective field and entering behind the safeguard.
05
Maintenance and Service Access
Maintenance personnel may need access to the lift enclosure, platform, drive system or transfer mechanisms that are not normally reachable during production. These access points often require a different safeguarding strategy from routine loading and unloading openings.
A light curtain used for normal production access should not be assumed to control maintenance risks by itself. Service access may require guarded doors, interlocking, safe isolation procedures or other measures defined by the machine risk assessment.
Typical concerns:
unexpected movement, stored energy, access inside guarded space and
restart after intervention.
System-Level Safeguarding
One Lift May Have More Than One Hazardous Opening
A common vertical-transfer machine has an opening at the lower level and another at the upper level. In that case, installing one safety light curtain at one opening does not automatically solve the safeguarding problem for the complete machine.
The safety logic may need to consider which opening is accessible, where the platform is located, what movement is permitted and what must happen before hazardous motion can restart.
01
Identify Accessible Openings
Map every location from which a person can enter, reach into or
bypass the guarded area.
02
Identify Hazardous Movements
Consider vertical platform travel, conveyor motion, load transfer,
closing gaps and other moving mechanisms associated with each
opening.
03
Define the Safe Response
Determine which hazardous movements must stop, remain inhibited or
be prevented from starting when a protective device is interrupted.
04
Prevent Unexpected Restart
The complete safety function should address how normal operation can
resume after the safeguarded area has been accessed.
Engineering Note
Do not design the safeguarding concept around the sensor first. Start with the hazard, the accessible opening and the possible approach path. Then select the protective device and safety-control architecture that can achieve the required risk reduction for the complete machine.
03 · Typical Applications
Where Industrial Lifts and Vertical Transfer Equipment Are Used
Vertical transfer equipment is commonly integrated into automated production and material-handling lines where products need to move between different conveyor heights, process levels or floors.
The safeguarding requirement depends less on the product being moved and more on whether personnel can access hazardous lift, conveyor or transfer movements through an opening.
Safety light curtains are particularly relevant where there is a defined access opening that needs non-contact monitoring while maintaining automatic material flow.
01
Appliance Manufacturing Lines
Large household appliances often move through several assembly, testing, storage or packaging stages at different heights. Vertical lift units can connect conveyor sections without requiring the complete production line to remain at one elevation.
At the loading and unloading openings, personnel may be able to reach the lift platform, moving load or conveyor-transfer area. Where the machine risk assessment requires electro-sensitive access protection, a safety light curtain can be integrated into the safety-related control system.
The design should also consider whether products routinely pass through the same opening, because material transfer and personnel access are different conditions that must be handled by the machine’s overall safety concept.
Typical Products
Refrigerators and freezer cabinets
Washing machines and dryers
Air-conditioning units and assemblies
Large appliance cabinets or subassemblies
Packaged finished products moving to storage or logistics areas
02
Pallet and Load Transfer
Vertical conveyor systems are commonly used to move pallets, containers or unit loads between conveyor levels. The transfer opening may expose personnel to both lift travel and powered conveyor movement.
Safeguarding should address access to the hazardous area without assuming that the presence of a pallet alone makes the opening safe.
03
Warehouse and Intralogistics Systems
Multi-level warehouses and automated material-handling systems may use vertical conveyors to connect storage, picking, packing and transport levels.
Depending on the layout, fixed guards, interlocked access points, safety light curtains or safety laser scanners may be combined to prevent personnel from entering hazardous transfer areas.
04
Cartons, Totes and Containers
Smaller goods can be transferred vertically between conveyor systems using lifts designed for cartons, totes or reusable containers. Frequent automatic product movement can make open transfer points attractive from a production perspective, but those openings still require risk-based safeguarding.
05
Automated Assembly and Process Transfer
A vertical transfer unit may move workpieces between assembly, inspection, testing or processing stations. These systems can include several coordinated axes, conveyors and fixtures rather than only one lifting platform.
The protective function therefore needs to consider the complete hazardous movement that remains accessible through the opening.
06
Multi-Level Production Transfer
Plants with production areas on different elevations may use industrial lift equipment to transfer materials between floors or mezzanine levels.
Each accessible level may require its own guarding arrangement, while the safety control system coordinates opening access with platform position and permitted movement.
Application Fit
When a Safety Light Curtain Is a Natural Starting Point
Light curtains are most naturally considered where personnel approach the hazard through a defined opening and a two-dimensional protective field can reliably monitor that access path.
| Application Condition | Safeguarding Consideration |
|---|---|
| Defined Loading Opening | A safety light curtain can monitor access through the opening where installation geometry and required safety distance allow. |
| Defined Unloading Opening | Similar access monitoring may be used at the upper or discharge side, subject to the hazards present at that location. |
| Frequent Automatic Transfer | The system design must distinguish normal material movement from unsafe personnel access using an appropriate, validated safety concept. |
| Open Access From Several Directions | A two-dimensional safety laser scanner or additional guarding may be more suitable than relying on one light curtain. |
| Maintenance Access Inside the Enclosure | Guarded and interlocked access, safe isolation or other measures may be required; a production opening light curtain should not be assumed to cover maintenance risks. |
Application Note
The same industrial lift can require different safeguards at different locations. A light curtain may be appropriate at a defined conveyor opening while an interlocked door, fixed guard or safety laser scanner is better suited to another side of the machine. Device selection should follow the access path and risk assessment rather than forcing one sensor type onto every opening.
04 · Safeguarding Function
How a Safety Light Curtain Protects an Industrial Lift Opening
A safety light curtain monitors the defined access opening. When a person interrupts the protective field, the sensor changes its safety output state so that the machine’s safety-related control system can respond.
In a properly designed industrial lift application, the protective device is connected into a complete safety function rather than used as an isolated sensor.
The required response may include stopping hazardous movement, preventing a lift cycle from starting or keeping particular motion inhibited until defined safe conditions have been restored.
The exact response depends on the risk assessment, machine design, safety control architecture, stopping performance and operating sequence.
01
Protective Field Monitors the Opening
The safety light curtain creates an electro-sensitive protective
field across the defined access path to the hazardous part of the
industrial lift or transfer machine.
02
A Person Interrupts the Field
When the required part of the protective field is interrupted, the
light curtain changes its safety output state according to the
device’s designed function.
03
Safety-Related Control Evaluates the Signal
A suitable safety-related control device or control system evaluates
the light curtain signal as part of the machine’s defined safety
architecture.
04
Hazardous Motion Is Stopped or Inhibited
The machine control system performs the required safe response, such
as stopping hazardous movement or preventing a new movement from
starting while the safety condition remains active.
05
Restart Follows the Validated Safety Logic
Clearing the protective field should not automatically be interpreted
as permission for unexpected hazardous movement. Restart behavior
must be defined by the complete machine safety concept and validated
for the application.
Typical Safety Architecture
Think in Terms of a Complete Safety Chain
The safety light curtain performs the detection function, but risk reduction depends on every part of the chain operating as intended.
A simplified architecture can be viewed as:
01
Safety Light Curtain
Detects access through the protective field.
02
Safety-Related Control
Evaluates the protective-device safety signals.
03
Final Control Elements
Remove or inhibit the energy that creates the hazardous movement.
04
Machine Reaches Safe Condition
Hazardous movement stops or remains prevented according to the
validated safety function.
What the Safety Light Curtain Does
- Monitors a defined access opening with an electro-sensitive protective field.
- Detects interruption of that protective field.
- Provides safety-related output signals for integration into the machine safety system.
- Supports non-contact access protection where the application and required safety distance allow.
What It Does Not Do by Itself
- Determine the complete required Performance Level of the machine.
- Guarantee that hazardous movement stops quickly enough for the installed safety distance.
- Prevent access around, above or below the protective field.
- Define safe restart logic for a person who may have entered the hazardous area.
- Provide muting by itself.
- Replace the complete machine risk assessment and validation process.
Automatic Material Transfer & Muting
How Products Can Pass Through the Protected Opening
On appliance, pallet and conveyor lift systems, the same opening may be used both for automatic material transfer and for personnel access. The safety architecture therefore needs to distinguish the intended passage of material from a person entering the protected area.
In the documented CCH application, this function is implemented with an ENT safety light curtain, a CCH-SR safety relay module, two external photoelectric sensors and two ordinary relays. The external photoelectric sensors provide the signals used to distinguish personnel from material movement.
Detection
ENT Safety Light Curtain
Monitors the protected access opening.
Identification
Two Photoelectric Sensors
Provide external signals used to distinguish material passage from
personnel access.
Signal Interface
Two Ordinary Relays
Collect and convert the muting-related signals in the documented
arrangement.
Safety Logic
CCH-SR Safety Relay Module
Integrates the ENT safety signals with the external muting signals
as part of the documented protection logic.
| External Sensor Condition | Documented Interpretation | Protection Principle |
|---|---|---|
| Only one photoelectric sensor is blocked | Interpreted as a person entering the protected area. | Personnel protection remains active and the safety function should respond according to the machine design. |
| Both photoelectric sensors are blocked simultaneously | Interpreted as material entering the protected area. | The documented muting logic allows the intended material transfer condition to be handled without treating it as personnel access. |
The muting function is not built into the ENT light curtain itself. ENT performs the electro-sensitive protective detection function. The additional photoelectric sensors, relays and CCH-SR safety relay module provide the external signals and logic used for the documented material-transfer muting arrangement.
Muting Application Note
Muting is not the same as simply bypassing the safety light curtain. The sensor arrangement, signal conditions, machine sequence and safety response must be engineered so that normal material transfer does not create uncontrolled personnel access. The two-sensor arrangement described here reflects the documented CCH application and should not be assumed to represent every possible machine or muting architecture.
Safety Engineering Note
The protective device and the safety function are not the same thing. The light curtain detects access; the complete safety function also includes signal evaluation, machine stopping or movement inhibition, prevention of bypass, restart behavior, muting where required and validation that the required risk reduction has been achieved.
05 · Light Curtain Selection
Choosing Safety Light Curtains for Industrial Lifts: ENT14, ENT25 or ENT45
ENT14, ENT25 and ENT45 define different detection-resolution platforms. The final light curtain model should then be selected according to the actual machine opening, required protective field, sensing distance, mounting method and safety-distance calculation.
The correct starting point is the detection capability required by the safeguarding application. A smaller numerical resolution can detect smaller objects, while a coarser resolution may be suitable only where the machine risk assessment permits it.
After the required resolution platform has been identified, the exact ENT model is selected to suit the installation. Industrial lifts that look similar can therefore use different ENT models because their opening height, approach geometry, sensing distance and mounting requirements are different.
ENT14
14 mm Resolution
Finer detection capability
Consider the ENT14 platform where the safeguarding concept requires detection of smaller objects or body parts and the resulting safety distance and installation geometry are appropriate.
Resolution
14 mm
Protection Height
Selected by specific model
Device Class
Type 4
ENT25
25 mm Resolution
Intermediate detection resolution
ENT25 provides an intermediate resolution option where 25 mm detection capability is appropriate for the risk assessment and installation geometry.
Resolution
25 mm
Protection Height
Selected by specific model
Device Class
Type 4
ENT45
45 mm Resolution
Coarser access-detection option
ENT45 may be considered where the risk assessment permits a coarser resolution and the safeguarding task is based on detecting larger objects or access through the protected opening.
Resolution
45 mm
Protection Height
Selected by specific model
Device Class
Type 4
Specific Model Selection
The Application Defines the ENT Model
ENT14, ENT25 and ENT45 identify the main detection-resolution platforms, but they are not complete model selections by themselves. The exact model should be chosen according to the required protection height, sensing distance, mounting method, response time and installation conditions.
For example, a model used in one previous industrial lift project should be treated as a project-specific configuration rather than a universal recommendation for other lift systems.
Selection Logic
Select the Platform First, Then the Exact Model
A practical selection process separates the required detection capability from the physical model configuration.
| Selection Factor | Why It Matters |
|---|---|
| Required Detection Resolution | Determines whether the application should start from the ENT14, ENT25 or ENT45 platform. |
| Protection Height | The selected model needs a protective field that covers the required access path. Protection height should match the safeguarding geometry rather than simply the machine opening dimension. |
| Sensing Distance | The emitter-to-receiver distance must be within the operating range of the selected ENT model configuration. |
| Mounting Method | Bracket configuration and mounting arrangement should suit the machine structure while maintaining the required protective field and preventing bypass. |
| Response Time | Use the response time of the exact model in the safety-distance calculation. Do not substitute a generic response time for the whole ENT family. |
| Application Environment | Installation space, contamination, vibration, ambient light, cable routing and other site conditions can affect the final configuration. |
Protective Field Geometry
Resolution, Protection Height and Opening Size Are Different Parameters
Resolution defines the minimum detection capability of the light curtain. Protection height defines the vertical extent of the protective field. The physical machine opening is the access geometry that must be safeguarded.
These three values should not be treated as interchangeable. The protective field should be selected and positioned so that the relevant access path is monitored while surrounding guarding prevents a person from reaching around, over or under the field.
The final model also needs to support the required emitter-to-receiver distance and installation method for the actual machine.
Avoid This Shortcut
“This model worked on another lift, so use the same model.”
Two vertical transfer machines can require different light curtain configurations because their detection requirement, protection height, sensing distance, mounting geometry and stopping performance are different.
Avoid This Shortcut
“It is Type 4, so the complete machine is automatically PL e.”
Type 4 describes the electro-sensitive protective equipment classification. The achieved Performance Level of the complete safety function depends on the full safety-control architecture, components, diagnostics and validation.
Selection Note
The safeguarding architecture can be defined before the exact ENT model is known. Once the required safety function, detection resolution and access geometry are established, the specific ENT model can then be selected to match the protection height, sensing distance, mounting method, response time and other site requirements.
06 · Safety Distance & Mounting
Safety Distance and Mounting Position for Industrial Lift Light Curtains
A safety light curtain must be positioned far enough from the hazard that the machine can reach the required safe condition before a person can reach the hazardous area.
For machinery applications, safety distance should be determined using the applicable safeguarding methodology, including ISO 13855:2024, together with the machine’s measured stopping performance and the response time of the protective device and safety-related control system.
On an industrial lift, the closest hazard may not always be the lift platform itself. Conveyor rollers, transfer mechanisms, closing gaps, moving loads and other hazardous movements may also affect the required mounting position.
01
Machine Stopping Time
Determine how long the hazardous movement takes to reach the required
safe condition after the safety function is initiated.
The actual machine stopping performance matters more than an
assumed value.
02
Light Curtain Response Time
Use the response time of the exact ENT model selected for the
application. Response time varies with the light curtain
configuration and should not be replaced with one generic value for
the whole product family.
03
Safety-Control Response
The total response can include the light curtain, safety relay or
controller, output devices and machine stopping elements. The
complete safety chain should be considered.
04
Approach Direction
How a person can approach the protective field affects the safety
distance assessment. A perpendicular approach, reach-over condition
or another access geometry should not be treated as the same case.
05
Detection Resolution
The selected detection resolution influences the safety-distance
calculation. This is why ENT14, ENT25 and ENT45 should not be chosen
independently from the final mounting geometry.
06
Location of the Actual Hazard
Measure the protective-device position relative to the hazardous part
that a person could actually reach, not simply relative to the front
face of the machine enclosure.
Mounting Geometry
Safety Distance Is Only Part of the Installation
Even a correctly calculated distance can be ineffective if personnel can bypass the protective field and reach the hazard without being detected.
Reach Over
Check whether a person can reach over the top of the protective field toward a hazardous point. The height and position of the light curtain need to be coordinated with the surrounding machine structure and fixed guarding.
Reach Under
Avoid leaving an accessible opening beneath the protective field that allows a person to crawl, reach or step into the hazardous area without interrupting the light curtain.
Side Bypass
Fixed guarding should prevent a person from walking around the transmitter or receiver and entering the hazardous area beside the protective field.
Access Behind the Light Curtain
If a person can pass completely through the protective field and remain inside the hazardous area, the safeguarding concept must address that condition before hazardous movement is allowed to restart.
Pass-Through Protection
What Happens After a Person Crosses the Light Curtain?
This is especially important on larger industrial lift openings. A person may interrupt the light curtain, enter the safeguarded space and then no longer block the protective field.
In this situation, restoring the light curtain field must not automatically mean that hazardous movement can restart. The machine safety architecture needs to address the possibility that a person remains in the hazardous area.
Depending on the machine design and risk assessment, additional measures may be required to control restart or detect continued presence within the safeguarded space.
Installation Review
Questions to Check Before Fixing the Mounting Position
| Check | Engineering Question |
|---|---|
| Stopping Performance | Has the actual stopping time of the hazardous machine movement been measured or otherwise properly determined? |
| Exact ENT Model | Is the response time of the selected model included in the safety-distance assessment? |
| Safety Control | Are the response times of the safety relay/controller and final control elements included where required? |
| Approach Path | Can a person approach perpendicular to the field, reach over it or access the hazard from another direction? |
| Bypass Prevention | Do fixed guards prevent access around, above or below the protective field? |
| Pass-Through Risk | Can a person enter the hazardous space completely and remain there after the field becomes clear again? |
| Restart Behavior | Is restart controlled so that clearing the light curtain does not create unexpected hazardous movement? |
Safety Engineering Note
Do not install a safety light curtain based only on available mounting space. Determine the required safety distance first, then confirm that the final position also prevents reach-over, reach-under, side bypass and uncontrolled pass-through access. The complete safeguarding function should be validated before the machine is placed into service.
07 · Multi-Level Safety Logic
Safeguarding Lower and Upper Openings on a Vertical Transfer System
A multi-level lift can have two or more accessible transfer openings. Each opening may present a different hazard depending on platform position, conveyor movement, material-transfer sequence and whether personnel can reach the lift travel area.
This means the safety system should not treat every light curtain as an isolated stop switch. The machine control architecture needs to know which hazardous movement is possible and which protective condition applies at each opening.
The final logic should be derived from the machine risk assessment and validated as a complete safety function.
Lower Level
Loading Opening
The lower opening may provide access to the lift platform, incoming conveyor and transfer mechanism. The safety logic should consider whether the platform is present, whether loading is permitted and what hazardous movement could occur if personnel enter.
Upper Level
Unloading Opening
The upper opening may expose a different combination of hazards, including platform travel, outgoing conveyor motion and access into the lift enclosure. It should be evaluated as its own safeguarding location rather than assumed to be identical to the lower opening.
Machine State
Platform Position Can Change the Hazard at Each Opening
A vertical transfer machine may have different safe and hazardous conditions depending on where the platform is located and which transfer operation is active.
| Machine Condition | Lower Opening | Upper Opening | Engineering Consideration |
|---|---|---|---|
| Platform at lower level | Loading or transfer may be permitted under the designed machine sequence. | Access may still expose a person to the lift travel area or other hazards. | Do not assume that the platform position automatically makes the opposite opening safe. |
| Platform travelling | Access to hazardous movement may need to remain prevented. | Access to hazardous movement may need to remain prevented. | Protective devices and control logic should reflect the hazard created by vertical travel. |
| Platform at upper level | The lower opening may expose access to the lift travel space or other hazardous mechanisms. | Unloading or transfer may be permitted according to the machine sequence. | Each level needs its own validated access and movement logic. |
| Maintenance or fault condition | Normal production safeguards may not be sufficient for service access. | Normal production safeguards may not be sufficient for service access. | Safe isolation, interlocked access or other maintenance measures may be required. |
Safety-Control Questions
What the Multi-Opening Logic Needs to Consider
01
Which Opening Is Being Accessed?
The safety system should respond to the protective device associated
with the actual access path and hazardous movement.
02
Where Is the Lift Platform?
Platform position can affect which transfer operation is permitted,
but it should not be treated as proof that every other hazard has
disappeared.
03
Which Movement Must Be Prevented?
The required response may apply to vertical travel, conveyor motion,
transfer mechanisms or several movements together.
04
Is Material Transfer Intended?
If products must pass through the protected opening automatically,
the material-transfer condition needs a defined and validated
muting strategy rather than an uncontrolled bypass.
05
Can a Person Remain Inside?
If someone can pass through a light curtain and remain in the
hazardous area, the restart concept must address that condition.
06
When Can Restart Be Permitted?
Restart should follow the validated machine safety logic and should
not result solely from the protective field becoming clear again.
Muting at Transfer Openings
Muting Should Follow the Actual Material Flow
Where a lower or upper opening is used for automatic product transfer, a muting function may be part of the safeguarding concept so that intended material can pass while personnel protection remains available for unauthorized access.
In the documented CCH arrangement, the ENT safety light curtain works with a CCH-SR safety relay module and two external photoelectric sensors to provide the personnel-versus-material identification logic.
However, a multi-level machine should not automatically copy the same sensor positions or muting logic from one opening to another. The direction of material travel, sensor geometry, conveyor sequence, platform position and access possibilities should be reviewed for each transfer point.
Avoid This Assumption
“If the platform is at this level, the opening is automatically safe.”
Platform position is only one machine-state input. Other moving mechanisms, accessible spaces and hazardous conditions still need to be considered.
Avoid This Assumption
“The lower and upper openings can use identical logic.”
They may look similar but can have different material flow, approach paths, hazards, stopping behavior and access conditions.
Safety Engineering Note
Multi-level lift safeguarding should be designed as one coordinated machine safety system. Lower-opening protection, upper-opening protection, platform position, conveyor state, muting conditions, permitted movement and restart behavior need to be evaluated together rather than as independent sensor installations.
08 · Light Curtain or Safety Laser Scanner?
When a Safety Laser Scanner May Be Better for an Industrial Lift
A safety light curtain is a strong choice for monitoring a defined opening, but not every industrial lift presents a simple doorway-style access path. Open floor areas and multi-direction access can require a different safeguarding approach.
A safety laser scanner monitors a configurable two-dimensional area rather than only a single vertical protective plane. This can be useful where personnel can approach the hazardous equipment from several directions or where an open floor zone needs to remain monitored.
Device selection should therefore follow the geometry of the access path and hazard, not a general preference for one sensor technology.
Defined Opening
Safety Light Curtain
A light curtain creates a protective plane across an opening. It is especially useful when personnel must cross a clearly defined boundary to reach the hazardous area.
- Loading and unloading openings
- Conveyor transfer openings
- Narrow or clearly defined personnel access paths
- Applications where fixed guarding controls access around the protective field
- Material-transfer applications using a validated muting concept where required
Open Area
Safety Laser Scanner
A safety laser scanner can monitor a two-dimensional field around equipment, which may be more suitable when the hazard cannot be protected by one clearly defined opening.
- Open floor areas beside the lift
- Personnel approach from several directions
- Area protection around transfer equipment
- Layouts where physical guarding cannot create one simple access opening
- Applications requiring configurable protective-area geometry
Selection Framework
Start With the Access Geometry
The following comparison is a starting point for engineering review, not a substitute for the machine risk assessment.
| Application Condition | Safety Light Curtain | Safety Laser Scanner |
|---|---|---|
| One clearly defined opening | Often a natural solution where the protective field can span the complete access path. | May be unnecessary if a simple protective plane adequately controls access. |
| Open floor area | One light curtain may leave alternative approach paths unprotected. | A configurable two-dimensional protective field may better match the area geometry. |
| Access from several directions | May require several light curtains plus additional fixed guarding. | Can be useful where one scanner position can monitor the relevant approach area, subject to the application design. |
| Material passes through a fixed opening | Often well suited where a validated material-transfer / muting concept is incorporated. | Selection depends on the required area logic and whether material movement affects the protective field. |
| Person may remain inside guarded area | The light curtain alone does not continuously detect someone after they have passed through the protective plane. | An area-monitoring arrangement may help address certain presence-detection requirements, depending on the complete layout and validated safety concept. |
| Very constrained mounting space | Can be effective when transmitter and receiver can be mounted across the opening. | Scanner location, field geometry and environmental conditions need to be evaluated before assuming it is the easier option. |
Typical Scanner-Oriented Layouts
Three Situations Where Area Monitoring Deserves a Closer Look
01
Open Side of a Transfer Area
If the lift or transfer unit sits in an open production area and personnel can approach from a broad side rather than through one narrow opening, area monitoring may fit the access geometry better.
02
Multiple Approach Directions
Where operators can walk toward the hazardous area from several directions, protecting only the front boundary with a light curtain may leave alternative access paths.
03
Presence Around Transfer Equipment
In some layouts, the engineering problem is not simply detecting a crossing event but monitoring whether a person occupies a defined hazardous floor area before movement is permitted.
Combined Safeguarding
Some Machines Need Both Technologies
An industrial lift does not have to use only one protective-device technology. For example, a safety light curtain may protect a defined conveyor opening while a safety laser scanner monitors an adjacent open access area.
Fixed guards, interlocked doors and other safety measures may also form part of the same machine safeguarding concept. The important point is that each measure addresses a defined access path or hazard and that their safety functions are coordinated and validated together.
Product-Class Distinction
Safety Laser Scanner ≠ General-Purpose 2D LiDAR
A general-purpose 2D LiDAR can provide measurement or raw scan data for navigation, localization, positioning or sensing applications, but it should not automatically be used as a substitute for a safety-rated laser scanner in a personnel-protection safety function. Where the application requires safety-related area monitoring, use equipment intended and assessed for that safety function.
Selection Note
Do not choose between a light curtain and safety laser scanner from product preference alone. Define the hazard, approach paths, required detection geometry, stopping behavior, environmental conditions and required safety performance first. The protective device should then be selected to fit that safeguarding function.
09 · Application Design Checklist
What to Define Before Selecting an Industrial Lift Safety System
A useful safety-light-curtain enquiry contains more than the opening width and required cable length. The application needs to be understood as a complete safeguarding problem.
The information below helps determine whether the application is better suited to a safety light curtain, safety laser scanner, interlocked guard or a combination of protective measures.
It also helps identify the appropriate ENT resolution, protection height, safety distance, control architecture and muting requirements where automatic material transfer is involved.
01
Machine & Hazard
- Type of industrial lift or vertical transfer equipment
- Hazardous vertical, conveyor and transfer movements
- Crushing, shearing, trapping or drawing-in hazards
- Locations where personnel can reach or enter the hazard
- Normal production, fault and maintenance operating states
02
Opening & Access Geometry
- Opening width and height
- Lower, upper or multi-level access
- Direction from which personnel can approach
- Possibility of reaching over, under or around the safeguard
- Whether a person can pass completely into the guarded area
03
Machine Stopping Performance
- Actual stopping time of the hazardous movement
- Response time of the selected protective device
- Safety relay or safety-controller response time
- Final control element and actuator stopping behavior
- Required safety distance from the accessible hazard
04
Product & Material Flow
- Product type and dimensions
- Direction of material travel through the opening
- Conveyor or transfer sequence
- Whether products must pass through the protective field automatically
- Whether a validated muting function is required
05
Safety Architecture
- Required safety performance from the machine risk assessment
- Existing safety relay or safety controller
- Machine stop / inhibit outputs
- Platform-position or machine-state signals where relevant
- Restart and reset strategy after protective-device interruption
06
Installation Environment
- Temperature and humidity
- Dust, contamination and cleaning conditions
- Ambient-light conditions
- Vibration and mechanical mounting constraints
- Cable routing and connector requirements
Project Information
What to Send With an Application Enquiry
A few practical pieces of information can reduce unnecessary back-and-forth and make the initial sensor recommendation much more useful.
| Information | Why It Helps |
|---|---|
| Machine photo or layout drawing | Shows the opening geometry, surrounding guarding and possible alternative approach paths. |
| Opening dimensions | Helps determine the required protection height and practical sensor mounting arrangement. |
| Product dimensions | Important when normal material passes through the same protected opening. |
| Material-flow direction | Helps evaluate the transfer sequence and any required muting arrangement. |
| Machine stopping time | Required for meaningful safety-distance engineering. |
| Existing safety-control hardware | Helps identify how the protective-device signals can be integrated into the existing machine safety architecture. |
| Required PL / safety requirement | Should come from the machine risk assessment and helps define the complete safety-function architecture. |
| Electrical and cable requirements | Helps select the appropriate product configuration and installation accessories. |
Recommended Design Sequence
Select the Sensor After the Safety Problem Is Defined
01
Identify the Hazard
Determine the hazardous movement and the person-access condition
that needs to be controlled.
02
Define the Required Safety Function
Define what must stop or remain inhibited when access is detected.
03
Define the Access Geometry
Decide whether the hazard is reached through a defined opening or
an open area with several approach directions.
04
Select the Protective Device
Choose the safety light curtain, safety laser scanner or other
protective measure that best matches the defined safeguarding task.
05
Calculate & Verify Installation
Determine safety distance, mounting geometry, bypass prevention,
muting requirements where applicable and restart behavior.
06
Validate the Complete Safety Function
Verify that the protective device, safety controls, stopping
elements and machine behavior achieve the intended risk reduction
before operation.
Discuss Your Industrial Lift Project
View ENT Type 4 Safety Light Curtains
View Safety Laser Scanners
Project Note
A useful sensor recommendation starts with the application, not with a model number. Photos, drawings, opening dimensions, material flow, stopping time and existing safety-control information are usually more valuable at the start of a project than simply asking for a light curtain of a certain length.
10 · FAQ & Project Resources
Industrial Lift Safety Light Curtain FAQ
These questions summarize the main engineering decisions for industrial lifts, vertical conveyors and automated material-transfer equipment.
Can a safety light curtain be used on an industrial lift?
Yes, where the machine risk assessment identifies a defined access opening that can be effectively monitored by an electro-sensitive protective field.
The light curtain must be integrated into the complete safety function, including safety-related signal evaluation, stopping or movement inhibition, bypass prevention, restart behavior and validation.
Should I use ENT14, ENT25 or ENT45 on a vertical transfer machine?
The lift type alone does not determine the correct ENT model. Selection should start with the required detection capability, access geometry, protection height, machine stopping performance and required safety distance.
ENT14 provides 14 mm resolution, ENT25 provides 25 mm resolution and ENT45 provides 45 mm resolution. The appropriate choice depends on the complete safeguarding assessment.
Can products pass through the same opening protected by a light curtain?
Yes, some automated material-transfer applications use a validated muting function so that intended products can pass through the protected opening while personnel access continues to be handled by the safety system.
Muting must be engineered as part of the complete machine safety architecture. It should not be implemented as an uncontrolled bypass of the protective device.
Does the ENT safety light curtain have built-in muting?
No. ENT performs the electro-sensitive protective detection function; the documented CCH muting arrangement uses external components.
The documented solution combines the ENT safety light curtain with a CCH-SR safety relay module, two external photoelectric sensors and two ordinary relays. The external photoelectric sensors provide the signals used to distinguish material movement from personnel access.
That documented arrangement should not be assumed to represent every possible machine or muting architecture. The actual equipment should be engineered and validated for its specific material flow and safety requirements.
Can an industrial lift restart automatically when the light curtain becomes clear?
Clearing the protective field should not automatically be treated as permission for unexpected hazardous movement.
This is particularly important where a person can pass completely through the light curtain and remain inside the hazardous area. The restart concept must be defined by the machine risk assessment and validated safety architecture.
How is the safety distance for an industrial lift light curtain determined?
The safety distance depends on factors including the machine stopping time, protective-device response time, safety-control response, approach geometry and detection resolution.
For machinery applications, the calculation should follow the applicable safeguarding methodology, including ISO 13855:2024, together with the actual stopping performance of the machine.
When should a safety laser scanner be considered instead of a light curtain?
A safety laser scanner may be better suited where personnel can approach from several directions or where an open floor area needs two-dimensional protective-area monitoring.
A safety light curtain is usually a more natural starting point for a clearly defined opening. Some machines may require both technologies together with fixed or interlocked guarding.
Can the lower and upper openings use the same safety logic?
Not automatically. Lower and upper openings can have different hazards, approach paths, material-flow directions and machine-state conditions.
Platform position, conveyor state, muting conditions, permitted movement and restart behavior should be evaluated for each opening and then coordinated as one complete machine safety system.
Related Resources
Continue the Application Review
Use the following product and engineering resources to continue the selection process after the application hazards and access geometry have been defined.
Product
ENT Type 4 Safety Light Curtains
Compare ENT14, ENT25 and ENT45 resolution platforms, protection heights, outputs and core technical specifications.
View Type 4 Safety Light Curtains →
Engineering Tool
ISO 13855 Safety Distance Calculator
Review the safety-distance relationship between protective-device response, machine stopping time and approach conditions.
Open Safety Distance Calculator →
Product Category
Safety Laser Scanners
Consider safety laser scanners where the application requires configurable two-dimensional area protection or personnel can approach the hazard from multiple directions.
View Safety Laser Scanners →
Product Category
Safety Light Curtains
Review the wider CCH safety-light-curtain product category and machine-guarding application context.
View Safety Light Curtains →
Standards References
Official Machinery Safety References
Final safeguarding design should use the standards applicable to the machine, market and risk assessment. Official standard information can be reviewed directly from the issuing organizations.
Industrial Lift Application Support
Send the Machine Layout Before Choosing the Sensor
For industrial lifts and vertical transfer systems, a useful first review should include the machine opening, hazard location, material flow and stopping behavior. This makes it easier to determine whether the application is best suited to a safety light curtain, safety laser scanner or a combined safeguarding concept.
Layout
Machine photos, drawings and opening dimensions
Material Flow
Product dimensions and transfer direction
Safety Data
Stopping time and required safety performance
Existing Controls
Safety relay/controller and machine-state information
Application note: This page provides general machinery-safeguarding guidance for industrial lifts and vertical transfer equipment. Final device selection, required safety performance, muting logic, mounting position, safety distance, restart behavior and validation should be determined for the actual machine through the applicable risk assessment and safety-engineering process.