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Engineering guide updated August 2026
Safety light curtain PLC integration is not simply a matter of landing two wires on two input terminals. Designers have to preserve a safety-rated path from the protective device, through evaluated logic, to the final switching elements—and then prove that the installed machine reaches its safe state soon enough.
Safety boundary: This guide is an engineering review aid, not a safety design, programming instruction, or conformity certificate. Use the exact light-curtain, input-module, controller, output-device, and machine manuals; apply the current standards and local law; and have the complete safety function validated by a competent person.
Across Rockwell GuardLogix and Siemens fail-safe controller platforms, the practical problem is the same: define what must stop, verify the electrical contract, evaluate both safety outputs, control reset and restart, monitor downstream devices where the architecture requires it, and retain evidence for commissioning and later changes. Platform terminology differs, but the lifecycle obligation doesn’t.
Safety light curtain PLC integration requires two compatible safety channels, evaluated safety logic, controlled final elements, deliberate reset behavior, measured stopping performance, and documented validation. GuardLogix and Siemens use different terms, but both must preserve the complete safety function.
Quick specifications to collect before design
- Exact light-curtain model, type, resolution, protection height, range, response time, and OSSD data
- Exact safety input/output module, controller, firmware, software, and network safety profile
- Required risk reduction, safe state, stopping-time data, access geometry, reset policy, and final-device feedback
- Applicable standards and editions, validation owner, change-control method, and proof-test interval
Key takeaways
- Green controller status does not prove the physical machine reached a safe state.
- OSSD test pulses, input tests, filters, and discrepancy settings must be checked as one electrical contract.
- Communication acknowledgment or reintegration readiness must remain separate from machine restart authorization.
- Validation is recurring lifecycle evidence, not a one-time beam-break demonstration.
Integration sequence in one minute
- Define the safety function, required risk reduction, and machine applicability.
- Confirm the exact light curtain and safety input are electrically and diagnostically compatible.
- Configure two-channel evaluation, discrepancy behavior, reset, output control, and communications.
- Test normal operation plus deliberate single faults and unexpected-restart scenarios.
- Measure stopping performance, document acceptance, and define revalidation triggers.
Can a Safety Light Curtain Connect Directly to a PLC?
Safety light curtains can exchange permitted status with a standard controller, but any signal that performs risk reduction must remain in the validated safety-related control path. Risk assessment determines whether that path uses a safety relay or safety controller, suitable safety input and output devices, and monitored final elements.
Can I wire a safety light curtain OSSD output directly to a PLC input?
Standard programmable logic controllers may receive a permitted auxiliary or diagnostic signal, but a normal input must not be assumed to perform the required risk-reduction function. When beam interruption must command a safe state, the evaluated path normally needs safety-rated inputs, safety logic, and suitable final switching elements selected from the machine risk assessment.
Safety Function Boundary Test: 3-Layer Boundary Map
This Safety Function Boundary Test identifies every signal and device whose failure could defeat the required risk reduction.
| Question | If yes | Evidence required |
|---|---|---|
| Does this signal initiate or maintain risk reduction? | Keep it inside the validated safety-related control architecture. | Safety requirements specification and architecture review |
| Could one undetected fault defeat the stop? | Review redundancy, diagnostics, fault exclusion, and common-cause measures. | Required and achieved performance calculation plus validation |
| Is the signal used only for status or production logic? | Standard controllers may consume it if the device manual permits. | Signal purpose, interface specification, and separation review |
| Will personnel enter a hazardous area for servicing? | Protective stops do not provide hazardous-energy isolation. | Energy-control procedure and isolating devices |
For a small, fixed function, appropriately selected safety relay modules may be suitable. Safety controllers become useful when several guards, operating modes, zone dependencies, or coordinated output functions must be managed. Convenience does not determine the required integrity: ISO 13849-1:2023 addresses the design and integration of safety-related control-system parts, while IEC 62061 covers a machinery safety lifecycle that includes integration, verification, configuration management, periodic testing, and validation.
Do not confuse a protective stop with isolation. Under the United States hazardous-energy-control rule, control-circuit devices are not energy-isolating devices. Where OSHA 29 CFR 1910.147 applies, servicing still needs the prescribed energy-control procedure.
The physical safeguard boundary matters too. A light curtain cannot prevent access around, over, under, or behind its sensing field. If a person can pass through and remain unobserved, the design needs supplemental guarding, presence detection, or another engineered measure so the safety function cannot be reset while someone remains exposed.
Dual-Channel OSSD Wiring and Input Compatibility
Most safety light curtains provide two output signal switching devices, commonly called OSSD1 and OSSD2. Treat them as a coordinated safety-output pair, not as two interchangeable status wires. Each channel must reach a separate compatible safety input, and the evaluated logic must detect the fault relationships required by the chosen architecture.
In a vertical installation, the light curtain acts as an active opto-electronic protective device: an array of photoelectric sensors creates a series of infrared light beams to detect the presence of an object in the protected field. Interruption changes the safety outputs; the automation controller then has to bring the machine to the specified safe state through the evaluated safety system.
| Item | What to record | Verify in exact manual |
|---|---|---|
| Safety outputs | Output type, normal state, off-state behavior, current limits | Light-curtain model and revision |
| Input compatibility | Permitted sensor type, input test behavior, filters, shared references | Safety input module and firmware |
| Channel relationship | Equivalent/complementary evaluation, discrepancy response, fault reset | Controller instruction or F-I/O parameters |
| Timing | Device response, input delay, discrepancy window, network watchdog | Every component in the response chain |
| Installation | Supply, cable, connector, shielding, grounding, environment | Manufacturer installation instructions |
What happens if only one OSSD channel is wired?
Using only one channel can remove the redundancy or diagnostic coverage on which the safety architecture depends. Even one active input may appear to stop the machine during a beam test, yet an open circuit, short, or stuck output could remain undetected. That is functional motion, not proof of functional safety.
Will OSSD test pulses cause problems with PLC inputs?
OSSD test pulses can cause problems when a safety output and safety input are incompatible. Safety outputs and safety inputs may use short test pulses to reveal wiring faults, but incompatible pulse timing or enabled input tests can create nuisance trips or mask assumptions about fault detection. Do not disable tests or lengthen filters merely to clear an alarm; compare the two exact manuals and document why the selected settings remain valid.
When not to use a light curtain
Light curtains are the wrong protective equipment when interruption cannot stop the hazard before a person reaches it, ejected material remains uncontrolled, or a person can enter and stay inside the safety zone unseen. Fixed or interlocked guards, door switches, perimeter guarding with additional presence sensing, safety laser scanners, or another machine-guarding measure may be necessary. Conveyor openings can also require tunnel guards or geometry that prevents reach-around access.
For a machine-specific U.S. example, OSHA prohibits presence-sensing devices on full-revolution-clutch presses and requires guards for every point-of-operation access route that the sensing field does not protect. This example does not replace the applicability review for another machine or jurisdiction.
Basic light curtains are not automatically suitable for every light curtain application, and choosing Type 4 does not by itself create the “highest safety” for the machine. Device type, resolution, mounting, safety distance from the hazard, stopping performance, safety functionality, and integration of multiple safety devices all matter. Required safety standards and type-C machine rules decide the application—not a product label alone.
Common search-language trap: “Wire OSSD outputs straight to the PLC” or “send the output to the PLC” omits whether the input is safety-rated. A non-safety input may be diagnostic only. Never mute a protective field or bypass a safety protocol simply to keep the machine cycle running.
Brand names do not close this gap. Keyence safety light curtains, the Keyence GL-R Series, Schmersal light curtain systems, and other light curtain sensors each have model-specific manuals and interfaces. The right light curtain for your application is the exact device whose output, response, environment, declarations, and safety input compatibility support the validated architecture—not the most familiar logo.
Even the shortened phrase “safety curtain” should refer to a specified protective device, not a generic sensor. Its purpose is to reduce a defined safety hazard within a validated machine function.
Using a safety relay can be appropriate for a bounded function, while a safety programmable logic controller may coordinate several zones and modes. IEC 61508 and ISO 13849 address different layers of functional safety; neither permits a designer to treat ordinary electrical compatibility as proof of an achieved machine safety target.
Supplier handoff: When selecting from a safety light curtain range, provide the planned safety input model—not just the controller brand. Compatibility has to be checked at the light-curtain, module, firmware, wiring, and parameter level.
Commissioning scenario: A new packaging cell stops correctly during ten ordinary beam interruptions, but faults after an operator brushes the edge of the field during product changeover. A channel trace shows one OSSD transition arriving outside the evaluated relationship. The team could hide the symptom by widening the discrepancy setting; instead, it checks alignment, terminal torque, cable routing, pulse compatibility, and input filtering against both manuals. A damaged connector produces the unequal transition. After replacement, the engineers rerun field interruption, both single-channel fault tests, reset, output feedback, and stopping-time measurement. The scenario shows why a passing beam test does not justify changing a safety parameter without finding the cause.
GuardLogix: From Safety Input to Signed Application
A GuardLogix project should begin with the exact device and module safety manuals, the machine safety requirements specification, and the selected Studio 5000 version. The public Rockwell DCS instruction documentation for version 37 is useful for understanding paired input evaluation, discrepancy timing, restart behavior, and fault handling, but its details must not be projected onto a different controller, module, or software revision.
Seven-step GuardLogix workflow
- Bind hardware: record the exact GuardLogix controller, safety input, output hardware, firmware, and safety manuals.
- Configure the device contract: confirm the two OSSD channels, input type, test pulses, filtering, and discrepancy model.
- Evaluate the pair: use the approved safety instruction and parameters from the exact version manual.
- Separate reset from start: define reset preconditions, edge behavior, cold-start policy, and restart authorization.
- Control final elements: connect the evaluated permissive to the specified safety output function and monitor downstream feedback where required.
- Validate faults and time: test both channels, discrepancy, reset, communications, output response, and total stopping performance.
- Freeze the evidence: retain the safety signature, project version, verification records, change approval, and restoration procedure.
Rockwell’s version 37 DCS page says the input points used by that instruction should be configured as single, because the instruction itself evaluates the dual-channel relationship. That is a version-specific instruction, not a universal setting. Follow the exact documentation for the selected input module and application instead of copying the word “single” into another configuration.
Discrepancy time is also not a nuisance-alarm knob. It represents the permitted relationship between channel transitions within the specified safety behavior. When a discrepancy fault occurs, investigate switching sequence, wiring, test pulses, filtering, mechanical alignment, and device diagnostics before considering any setting change.
For CIP Safety paths: The network is part of the safety function. ODVA describes time expectations, production identifiers, safety cyclic redundancy checks, redundancy, and the Safety Network Number as integrity measures. Record who owns these parameters, how replacements are commissioned, and how an unauthorized configuration is detected.
Validation boundary: A controller-ready signal is only the beginning; the installed safety function has to be tested through the final machine response.
Change-control scenario: During maintenance, a team replaces a failed networked safety input with the same catalog family and restores the saved controller project. Its input data appears healthy, yet the replacement has different firmware and its safety network identity has not been verified against the approved record. Production pressure makes a quick signature acceptance tempting. A disciplined GuardLogix workflow stops there: the team confirms the exact replacement compatibility, safety network number, module ownership, firmware, project signature, and affected fault tests before release. The lesson is broader than one platform. “Same family” and “online without faults” are logistics observations; neither proves that the replacement belongs to the validated configuration.
Safety signatures and locked configurations support change control; they do not prove that the mechanical stopping system, mounting position, downstream actuators, and access geometry are safe. ISO 13849-2:2012 defines validation as analysis and testing of the specified safety functions, achieved Category, and achieved Performance Level. Signed applications still need machine-level validation, and any relevant hardware, firmware, logic, parameter, network, or mechanical change needs impact review and appropriate revalidation.
Siemens F-CPU: F-DI Evaluation, Passivation, and Reintegration
The Siemens workflow uses different names but follows the same safety contract. Begin with the exact F-CPU, fail-safe digital input, TIA Portal version, light-curtain output data, and system manual. A publicly accessible older Siemens F-DI/DO module page shows how two-channel evaluation, discrepancy behavior, short-circuit tests, passivation, and reintegration can interact; the current model’s manual remains authoritative.
Seven-step Siemens workflow
- Establish the F-system boundary: list the exact F-CPU, F-I/O, firmware, safety program, and final elements.
- Parameterize the F-DI: match sensor evaluation, channel assignment, supply/test behavior, delay, and discrepancy handling to the exact manuals.
- Define passivation response: state what substitute values and safe outputs occur for channel, module, or communication faults.
- Define acknowledgment and reintegration: require valid channel states and the documented acknowledgment conditions.
- Separate production restart: restoring valid F-I/O data must not by itself initiate hazardous machine motion.
- Test the complete response: validate interruption, faults, watchdog behavior, reset, output control, and measured stopping performance.
- Archive acceptance evidence: retain the safety program checksum/signature, F-parameters, acceptance test, and approved change record.
Siemens manuals may describe a discrepant channel using its last valid value or a zero value, depending on the configured behavior and module. That choice can change the safety response and reintegration conditions. It therefore belongs in the safety requirements specification and test record, not in a commissioning technician’s undocumented preference.
PROFIsafe status is another place where terminology can mislead. IEC 61784-3-3 notes that implementing a safety communication profile in a standard device is not sufficient to qualify that device as a safety device. Endpoint hardware, software, configuration, and application still need the required safety properties.
Acknowledgment is not restart. PROFIsafe services such as operator acknowledgment, communication readiness, or parameter-transfer confirmation support a safe communication lifecycle. They do not independently establish that the protected area is clear or authorize the machine to resume hazardous motion.
Reintegration scenario: A Siemens fail-safe input passivates after one channel remains low beyond the configured relationship. Once the wiring is repaired, valid process data returns and the module becomes eligible for reintegration. The machine still must not restart merely because the F-I/O is healthy. The application first confirms both safety channels, the protected-area condition, downstream output state, and the deliberate acknowledgment or reset sequence defined by the safety specification. Only then can a separate operational start be accepted. This distinction prevents a communications recovery, power restoration, or technician acknowledgment from becoming an unexpected-motion command.
| Integration category | GuardLogix review | Siemens review |
|---|---|---|
| Two-channel evaluation | Approved safety instruction and safety input configuration | F-DI sensor evaluation and channel parameters |
| Channel mismatch | Discrepancy timing and instruction fault behavior | Discrepancy, passivation, substitute value, reintegration |
| Safe communications | CIP Safety identities, timing, CRC, Safety Network Number | PROFIsafe address, watchdog, F-parameters, endpoint qualification |
| Application release | Safety signature and controlled project version | Accepted safety program and controlled F-configuration |
| Reset | Manual/automatic restart option, cold-start behavior, reset input | Acknowledgment, reintegration conditions, application reset logic |
| Safe outputs | Safety output instruction and final-device architecture | F-DO configuration and final-device architecture |
| Diagnostics | Instruction faults, module state, network safety diagnostics | Channel/module diagnostics, passivation, PROFIsafe state |
| Change control | Signature comparison, approved project, replacement procedure | Program/F-parameter acceptance, checksum, replacement procedure |
| Machine-level proof | Fault testing, stop-time measurement, access review, reset/restart test, validation, and change control | |
Reset, Restart Interlock, and External-Device Monitoring
A light-curtain reset should deliberately restore safety readiness without starting hazardous motion, while external-device monitoring should reveal a final switching device that failed to follow the safe command. Reset location, sequence, feedback contacts, timing, and fault response must come from the safety specification and exact evaluated architecture.
Safe state sequence
Beam clear and faults corrected → safety channels valid → deliberate reset accepted → safety function ready → separate operational start permitted → hazardous motion begins only when every machine condition is satisfied.
Locate a manual reset where the operator can verify the safeguarded area, but cannot reach the reset while remaining inside an unobserved hazard zone. Review deliberate actuation, edge detection, stuck-button behavior, cold start, power restoration, mode changes, and reset after a communication or discrepancy fault.
External-device monitoring—or the architecture’s equivalent feedback function—checks whether final switching devices actually follow the commanded safe state. The correct placement, feedback contact type, timing, diagnostic coverage, and fault response depend on the evaluated architecture and exact manuals. There is no safe universal timeout or one wiring pattern for every contactor, drive, relay, and controller combination.
| Do | Do not |
|---|---|
| Define reset, readiness, start, and reintegration as separate events. | Use “fault cleared” as an automatic production-start command. |
| Test welded/stuck final devices and missing feedback where the design supports it. | Assume an output status bit proves the contactor or drive reached its safe state. |
| Use architecture-specific timing and acceptance criteria. | Increase a timeout until nuisance faults disappear. |
Commissioning With the Five-Fault Test Record
A beam-break demonstration proves only the most visible success path. Commissioning should also show that relevant single faults are detected, that the safe state is maintained as specified, that recovery follows the approved sequence, and that the evidence can be repeated after a change.
Five-Fault Commissioning Record
This Five-Fault Commissioning Record ties each controlled fault to its safe response, diagnostics, recovery rule, measurement, evidence identifier, and approver.
| Test | Controlled stimulus | Expected evidence |
|---|---|---|
| 1. Protective-field interruption | Interrupt each defined area of the sensing field using the prescribed test piece and method. | Safety output change, controlled safe state, measured stopping performance, no unintended restart |
| 2. Channel 1 fault | Apply the safe, documented simulation permitted by the validation plan. | Detected fault, safe response, diagnostic identity, controlled recovery |
| 3. Channel 2 fault | Repeat independently for the second channel. | Equivalent detection and response without hidden channel dependence |
| 4. Relationship fault | Create an approved timing, discrepancy, cross-fault, or communication fault supported by the architecture. | Specified passivation/fault state, stable diagnostics, permitted reintegration only |
| 5. Reset and final-device fault | Test stuck reset, power restoration, or downstream feedback failure as applicable. | No unexpected restart; final-device failure prevents unsafe enable and is diagnosed |
Each row needs more than “pass.” Record the precondition, test method, expected safe state, actual result, diagnostic code, response-time or stopping-time evidence, drawing and software revision, instrument identity, tester, approver, and date. Link photographs or trace files to stable evidence identifiers rather than leaving them on a commissioning laptop.
Revalidation triggers: Treat the record as a lifecycle tool. Repeat the affected tests after changes to the light curtain, mounting, wiring, safety I/O, controller, firmware, logic, parameters, network safety settings, output devices, braking system, machine process, or guarding—and when measured stopping performance drifts.
Some machinery-specific rules require checks more frequently. For mechanical power presses operating in the qualifying presence-sensing-device-initiation mode, OSHA requires specified checks at the beginning of each shift and after a die change, plus annual recertification and third-party revalidation. Do not transplant these duties or safety-distance expressions to unrelated machines; first determine which regulations and type-C standards govern the actual equipment.
| Symptom | Investigate first | Unsafe shortcut |
|---|---|---|
| Intermittent discrepancy fault | Channel traces, terminals, cable, test pulses, filters, alignment, output timing | Blindly extend discrepancy time |
| Input passivates during startup | Supply sequencing, startup tests, F-parameters, valid channel states | Force or bypass the safe value |
| Reset accepted but machine will not start | Separate safety readiness from operational interlocks and start logic | Tie reset directly to start |
| Output says off but motion remains | Final elements, stored energy, brake, drive state, feedback, stop-time measurement | Treat a controller bit as physical proof |
Safety Distance, Current Standards, and the Limits of Code
The official ISO catalog identifies ISO 13855:2024 as the current international standard for positioning safeguards with respect to the approach of the human body; the 2010 edition is withdrawn. Its scope and exclusions matter. Machine-specific standards, local regulations, approach geometry, and foreseeable access can change what method applies.
A separation-distance result depends on the complete response chain, not only the light curtain’s response time. Inputs can include sensor response, safety input and logic delay, safe communications, output-device response, actuator and machine stopping performance, object sensitivity or intrusion allowance, mounting geometry, and measurement uncertainty. The final value must use measured and validated project data.
| Input | Source of truth | Acceptance evidence |
|---|---|---|
| Applicable method and edition | Current standard, local law, machine-specific standard | Applicability review |
| Protective-device response | Exact light-curtain manual and configuration | Model/revision record |
| Control and output response | Safety I/O, task, network, output, drive/relay data | Configuration plus trace/test |
| Machine stopping performance | Worst-case validated measurement | Instrumented stop-time report |
| Access and intrusion terms | Resolution, orientation, reach, mounting, supplemental guards | Drawing and physical inspection |
This guide deliberately does not provide a reusable installation distance or a copy-and-paste code example. A numerical example can look precise while hiding the wrong standard, machine class, approach direction, or stopping-time assumption. Use a qualified calculation based on the installed machine, then verify the actual stopping performance at commissioning and after relevant changes.
Design aids: Use the site’s performance level and safety integrity level mapper to organize—not certify—the required target, then review the Type 2 versus Type 4 decision tree before specifying a device.
Integration and Procurement Checklist
“Compatible with GuardLogix” or “for Siemens PLC” is too vague for a safety-function handoff. The request should identify the exact protective device, safety I/O, controller, firmware, network, output architecture, environmental conditions, required risk reduction, and validation owner. Missing information should trigger a clarification, not a guessed parameter.
| Requirement | Required evidence | Recommended range | Reject / clarify when |
|---|---|---|---|
| Machine and hazard | Risk assessment, task zones, safe state, applicable standards | Exact project-specific requirement | Only a machine name or photo is supplied |
| Protective field | Protection height, resolution, range, mounting, access review | Calculated from the guarded opening | Pass-through or reach-around risk is unaddressed |
| Light-curtain interface | Exact model, type, OSSD data, test pulses, response time, manual revision | Exact model-specific values | Controller brand is the only compatibility detail |
| Safety controller path | Controller, safety input/output, firmware, network, instruction/F-parameter set | Approved compatible combination | Safety I/O or firmware is unspecified |
| Safe communications | Protocol, endpoint, address/identity, watchdog, ownership, replacement procedure | Exact validated parameters | A network name is treated as device qualification |
| Reset and final elements | Restart policy, reset location, contactor/drive data, feedback architecture | Risk-assessed project design | Reset is described as machine start |
| Environment | Temperature, ingress, vibration, contamination, electromagnetic conditions, cable route | Site-specific operating envelope | Ambient and washdown conditions are unknown |
| Safety distance | Applicable method, response chain, measured stopping performance, geometry | Validated project calculation | A reused distance or catalog value is proposed |
| Documentation | Manuals, declarations, drawings, parameter report, software version, bill of materials | Controlled revision set | Evidence cannot be tied to exact models |
| Acceptance | Stop-time method, five-fault record, drawings, signatures, change control | Named owner and acceptance criteria | No competent validation owner is assigned |
For a robot cell, include mode selection, teach operation, perimeter and in-zone safeguarding, robot and process hazards, escape or trapped-person risk, safe-speed functions, and reset visibility. The robot-cell safety applications page can help frame the device discussion, but the cell integrator must validate the complete application.
QJKH is the brand of CCH Shanghai Sensing Intelligence Technology Co., Ltd, a Hangzhou-based supplier of safety light curtains, safety laser scanners, safety relay modules, and industrial sensing products. The company states that its core team has more than 20 years of industrial-safety experience and offers original-equipment-manufacturer customization; these are first-party company statements, not independent certification evidence for a specific installation.
Useful supplier question: “Please identify the exact light-curtain model, output characteristics, response time, manual revision, available declarations, environmental limits, connector/cable, and known compatibility evidence for our specified safety input module.” That question produces an auditable answer; “Will it work with Siemens?” usually does not.
Frequently Asked Questions
Can a safety light curtain connect to a standard PLC?
Can a safety light curtain connect to a standard PLC?
A standard controller may receive an allowed diagnostic signal, but that signal must not be assumed to perform the required safety function. If beam interruption must reduce risk, use an evaluated path with suitable safety-rated inputs, logic, and final elements, then validate the complete installation. Keep the diagnostic path visibly separated from the validated safety path in drawings, software tags, and the acceptance record.
Should I use a safety relay or a safety PLC?
Should I use a safety relay or a safety PLC?
A safety relay can suit a small, fixed function supported by the relay’s evaluated architecture. A safety controller is useful for multiple protective devices, modes, zones, diagnostics, or coordinated safety functions. Start with the risk assessment and safety requirements specification rather than component cost alone. Verify that the selected input, logic, outputs, diagnostics, wiring, and test method can achieve the required target together.
What causes a dual-channel discrepancy fault?
What causes a dual-channel discrepancy fault?
Possible causes include miswiring, a damaged conductor, unequal channel switching, incompatible test pulses, filtering, a device fault, or an unsuitable parameter. Compare recorded channel timing and diagnostics with the exact manuals, correct the cause, and repeat the validation test instead of automatically increasing the discrepancy window. Save the channel trace and final setting with the commissioning evidence so a later change can be compared.
How should a light-curtain reset work?
How should a light-curtain reset work?
Reset behavior comes from the safety requirements specification. A manual reset should be deliberate, occur only after safe conditions are restored, and shouldn’t itself start hazardous motion. Its location, visibility, stuck-button response, and relationship to operational start need application-specific review.
Test the reset after a field interruption, each relevant channel fault, power restoration, input passivation, communication recovery, and final-device feedback fault. A valid input or acknowledgment may restore readiness, but the operator should still inspect the protected area and use a separate start command. If a person can remain behind the sensing field, additional presence detection or a trapped-person prevention measure is required.
Can GuardLogix and Siemens use the same light curtain?
Can GuardLogix and Siemens use the same light curtain?
Potentially, if the exact light-curtain electrical characteristics and safety properties are compatible with each selected safety input and architecture. Verify output type, pulse behavior, channel evaluation, response time, diagnostics, reset and monitoring functions, manuals, firmware, and validation requirements separately for each platform.
Does this guide establish the required safety distance?
Does this guide establish the required safety distance?
No. It identifies inputs for a qualified review, but the result depends on the applicable standard, measured stopping performance, full control response, mounting, approach geometry, object sensitivity, and project conditions. Never reuse an illustrative or another machine’s value.
Build the Evidence Package Before You Build the Panel
A defensible light-curtain integration is a chain of compatible components, explicit safety requirements, controlled configuration, physical safeguarding, measured stopping performance, fault testing, and retained approval evidence. GuardLogix and Siemens organize that chain differently, but neither platform turns a wiring diagram or a green status bit into machine-level validation.
Preparing a new integration?
When you ask for a model-specific compatibility review, send the light-curtain requirements, safety input model, controller and firmware, machine risk target, environment, reset and output architecture, and validation plan.
Editorial note: Product and experience statements attributed to CCH Shanghai Sensing Intelligence Technology Co., Ltd are first-party claims; final safety performance and compliance depend on the complete validated application.
Related engineering resources
References & Sources
- ISO 13849-1:2023, Safety-related parts of control systems
- ISO 13849-2:2012, Validation of safety-related control-system parts
- ISO 13855:2024, Positioning of safeguards
- IEC 62061 consolidated edition, Machinery functional safety
- IEC 61784-3-3, PROFIsafe communication profile
- ODVA, CIP Safety overview
- PROFIBUS & PROFINET International, PROFIsafe overview
- OSHA 29 CFR 1910.147, Control of hazardous energy
- OSHA 29 CFR 1910.217, Mechanical power presses
- OSHA Machine Guarding eTool, Presence-sensing devices