Why security technology is essential
Personal safety always comes first. Property protection follows. Availability and productivity remain paramount.
Good safety technology prevents accidents. It reduces downtime. It lowers liability risks for operators.
Proper planning saves costs. Mistakes in selection increase project costs and complicate subsequent acceptance.
Terms in the context of gate systems
Activation sensors trigger travel commands. Safety sensors prevent hazards. The two must be separated.
Closing edge safety devices protect against pinch points. Light barriers secure danger zones. Light grids monitor areas.
Wicket door contacts prevent travel when the pedestrian door is open. Slack rope switches secure rope guides.
Protection goals in practice
Stop in case of danger. No unexpected start-up. Only reset in a controlled manner. Simple. Clear. Verifiable.
Components must be suitable. Protection classes and temperature ranges must be observed.
Electrical design follows the control category. Faults must not lead to dangerous conditions.
Technical documents
Plans, parts lists, and circuit diagrams are required, along with test reports.
An operating manual is binding. It must be understandable. It guides you through inspections and maintenance.
Labels must be permanently legible. This applies to sensors and controls.
Light barriers
Light barriers detect interruptions along a line. They secure passageways and crush zones.
There are one-way and reflection systems. One-way offers greater interference immunity. Reflection simplifies installation.
Important features include range, response time and IP protection class.
- To light barriers
- Typical mounting height: 200–300 mm above floor
- Optional second level at 700–900 mm
- Pay attention to shielding against sunlight
Light grid
Light grids monitor areas with multiple beams. They are suitable for industrial and high-speed doors.
Resolution and protective field height determine detection. The finer the resolution, the more sensitive.
Many systems offer integrated self-tests, which improves diagnostics.
- About light grids
- Preferred for wide openings
- Ideal for high foot traffic
- Note limited range
Optosensors for closing edges
Optical closing edge sensors are located in the rubber profile edge. They detect deformation using light.
They respond quickly and are robust. They require reliable signal transmission to the drive.
Radio modules or spiral cables connect the edge to the control system.
- About optosensors
- High sensitivity at the main closing edge
- Suitable for sectional, roller and sliding doors
- Schedule regular functional tests
Resistive closing edge safety device (8k2)
Resistive edges detect pressure via resistance changes. 8k2 stands for 8.2 kΩ quiescent current monitoring.
The technology is proven and cost-effective. Wiring is simple.
The evaluation can take place in the controller or in the transmitter.
Slack rope switch
Slack rope switches monitor rope tension. They stop the drive if the rope slackens.
They are mandatory for rope-driven systems. They protect against uncontrolled movement.
Mounting on the rope run with clear pulling direction.
- To slack rope switches
- Test mechanical function regularly
- Document limit switch position
Wicket door contacts
Wicket door contacts prevent travel when the pedestrian gate is open. They are designed to open automatically.
They belong in the security circuit. Tamper-proof installation is important.
The cable routing must be protected.
- To wicket door contacts
- Show contact status on the display
- Check for continuity regularly
Spiral cables and junction boxes
Coiled cables transmit signals to the moving gate bar, allowing for high stroke rates.
The selection depends on the cable length and number of wires. Strain relief is mandatory.
Junction boxes must be potted and sealed.
- About spiral cables
- Plan your range of motion carefully
- Schedule a test for line breaks
Radar motion detector
Radar is an activation sensor. It opens gates without contact. It is no substitute for security.
Modern devices differentiate between walking directions, reducing false alarms.
Mounting height and inclination strongly influence the detection field.
- To radar detectors
- Combine with security technology
- Align fields to traffic flow
Controls and safety circuits
The controller links sensors and the drive. It evaluates conditions and executes the stop.
Industrial controllers offer adjustable responses. Time profiles and test cycles are configurable.
Safe inputs monitor NC circuits. Test pulses check the sensor status.
Procedure in four steps
- Identify and describe hazard areas
- Assess risk and determine protection level
- Select measures and implement them technically
- Check and document effectiveness
Typical chain of measures
First defuse constructively. Then secure. Finally, add organizational support.
The higher the risk, the more redundancy is needed. Test cycles must be appropriate.
Retrofits require a new assessment. Every change must be evaluated.
Sectional garage doors (private)
- Main closing edge with optical or resistive edge
- Light barrier at 200–300 mm, optional second level
- Wicket door contact with integrated pedestrian door
- Spiral cable or radio transmission of the edge
Components: closing edge sensor , light barrier , wicket door contact .
Industrial sectional doors
- Main closing edge with optical edge, fast reaction
- Light grid across the entire opening width
- Additional light barrier outside for apron security
- Use redundant safe inputs in the controller
Components: light grid , opto-edge , control .
High-speed doors
- Area protection with high-resolution light grid
- Self-testing sensors for short cycles
- Smooth wiring with high-cycle spiral cable
- Fine parameterization of the overtravel paths
Sliding gates
- Safety edge on the leading door leaf
- Light barriers in the passage area
- Additional edges at shear points behind the post
- Radar only as activation, not as protection
Components: closing edge , light barriers .
Swing gates
- Light barrier across the opening
- Safety edges on the leading and hinge side
- Wicket door contact with integrated pedestrian door
- Clean cable routes to avoid chafing
Roller shutters
- Optical closing edge in the end strip
- Light barrier inside and outside
- Slack rope switch for rope-driven axles
- Spiral cable dimensioned for stroke rate
Loading technology
- High-visibility signaling technology
- Blocking circuits active when the door is moving
- Forklift flow radar with direction detection
- Control with clear diagnostic codes
Components: loading controls , radar .
Range, resolution, response time
Light barriers need buffers to protect against dirt. Plan for buffers.
Choose your light grid based on resolution. A higher resolution detects smaller objects.
Reaction time determines the safety distance. Follow-up distances must be taken into account.
Electrical properties
The voltage and output type must match the controller. PNP and NPN are both possible.
Safe inputs await monitored NC circuits. Test pulses are possible.
Bus systems simplify wiring. They require suitable modules.
Mechanics and assembly
Mounts must be torsionally rigid. Adjustment angles must remain fixable.
Cable routing needs protection from kinks. Strain relief is mandatory.
Spiral cables are dimensioned according to the stroke and number of wires.
Compatibility and extensibility
Plan for future sensors. Controllers should have free inputs.
Pay attention to diagnostic functions. This saves time during service.
Documentation and labeling save many hours.
Installing light curtains
- Define and mark the protective field
- Attach and wire profiles
- End-to-end test with calibration rod
- Test shading over the entire height
- Documentation with photos
Integrate closing edge
- Cut and insert the rubber profile
- Insert optics or 8k2 resistor
- Connect transmitter or spiral cable
- Secure and label the cable route
- Check stop function under load
Check wicket door contact
- Check mechanism for positive opening
- Measure contact in the safety circuit
- Eliminate malfunction due to door play
- Document switching point
- Perform stop test
Example: 8k2 edge
The 8.2 kΩ edge is connected to an evaluation unit, which monitors the quiescent current.
When deformation occurs, the resistance changes. The control system triggers the stop.
The cable must be protected against breakage.
Example: Optical edge with radio
The transmitter is located in the end bar. It transmits the status to the receiver.
Power is supplied via rechargeable batteries. Charging cycles must be planned.
The radio link must be tested regularly.
Example: Light barrier at secure entrance
The receiver delivers a safe NC signal. This goes to the safe input.
The test pulse line is connected. The controller performs cyclic tests.
Errors are displayed on the display.
Permanent safety shutdown
Check for wire breaks or short circuits. Tighten terminals.
Check the contact logic in the controller. Don't confuse NC and NO.
Parameterize test pulses correctly.
Unclear interference with radio edges
Check battery status. Position antenna correctly.
Change the radio channel. Identify sources of interference.
Cross-wire with spiral cable for testing.
Service-friendly planning
Label all sensors. Document cable colors.
Place diagnostic indicators in clearly visible locations.
Mark screw connections.
Monthly checks
- Function of all light barriers with test piece
- Shading of the light grid over the entire height
- Stopping behavior of the closing edge at three points
- Test wicket door contact for forced opening
- Mechanically trigger slack rope switch
Annual audits
- Update documentation and labels
- Check spiral cable for breaks
- Replace housing seals if necessary
- Save and version control parameters
- Check spare parts list and minimum stock
Optical vs. resistive closing edge
Optical edges react very quickly. They are insensitive to temperature.
Resistive edges are simple and inexpensive. They are easy to test.
The choice depends on the speed and type of goal.
Wireless transmission vs. coiled cable
Wireless technology eliminates the need for cables. However, batteries require maintenance.
Coiled cables are robust. They require correct sizing.
For high cycle counts, cable is often the best choice.
Checklist selection
- Gate type, size, speed documented
- Passenger flow and vehicle types known
- Hazard zones mapped
- Protection level set
- Sensors selected by zone
- Control compatible and expandable
- IP protection and temperature tested
- Documentation planned
Assembly checklist
- Holder aligned and screwed
- Cable routes protected and labeled
- NC circuits checked
- Test pulses configured
- Emergency stop tested
- End stops checked
- Photo documentation created
Commissioning checklist
- Functional test of all sensors
- Stop distances measured and recorded
- Parameterization secured
- Operator instructed
- Maintenance plan handed over
Minutes template short form
Is a light barrier sufficient for industrial gates?
Not for high pedestrian traffic. A light curtain is a better choice.
How often must it be checked
Inspection intervals depend on usage: monthly for brief inspections. Annually for detailed inspections.
Can I retrofit wireless edges
Yes. Make sure you use appropriate recipients and ensure reliable evaluation.
Which height for light barriers
200–300 mm is standard. Add a second level if needed.
Further cornerstones in planning: Smart Home for gates , gate seals , and sectional garage doors .
