Open-plan offices present one of the most demanding environments for KNX lighting commissioning. Large, open floor plates, shifting occupancy patterns, and the need to balance energy efficiency with occupant comfort mean that a poorly configured presence detection system will frustrate users and waste energy in equal measure. Getting KNX occupancy-based lighting right in these spaces requires a methodical approach, from the earliest planning stages through to final on-site tuning.
The good news is that KNX gives installers a genuinely powerful toolkit for presence-based lighting control. With the right commissioning sequence, even complex open-plan environments can be made to respond intelligently, adapting lighting scenes to actual occupancy rather than fixed schedules. The sections below walk through that sequence step by step.
Mapping zones and sensor coverage before programming
Before a single group address is written, the physical layout of the space needs to be translated into a logical zone map. In an open-plan office, this means dividing the floor plate into distinct detection areas, typically aligned with structural bays, workstation clusters, or circulation routes, and confirming that each KNX motion sensor covers its intended zone without significant overlap or blind spots.
Walk the space with the sensor datasheets in hand. Check the manufacturer’s coverage angles and mounting height recommendations, then verify these against the actual ceiling height and furniture layout. Partitions, shelving units, and even large monitors can create shadow zones that a sensor cannot see. Identifying these gaps before programming saves significant rework later. Document each zone with a simple floor plan annotation. This becomes the reference throughout the commissioning process.
Configuring group addresses for occupancy-triggered scenes
With zones defined, the next step is building the group address structure that will link each KNX presence sensor to the appropriate lighting outputs. A clean, logical group address plan is essential in open-plan offices because multiple sensors often need to interact: a zone may remain lit if an adjacent zone is occupied, for example.
A practical approach is to create separate group addresses for occupancy status, scene recall, and manual override for each zone. This separation makes it straightforward to apply different logic to each function without tangling the addressing. Occupancy sensors typically send a binary telegram, occupied or unoccupied, and this value can be used to trigger a scene object on the lighting actuator or DALI gateway. Where zones share luminaires, use group linking carefully to avoid unintended interactions between adjacent detection areas. Full xxter product and compatibility information is available for integrators planning this stage.
Setting hold times, sensitivity, and daylight thresholds
The behaviour of a KNX motion sensor lighting system is largely determined by three parameters: hold time, sensitivity, and the daylight threshold. Each needs to be calibrated to the specific characteristics of the zone it serves, not simply left at factory defaults.
Hold time, the period a zone stays lit after the last detected movement, should reflect the typical activity pattern of that area. A focus workstation zone warrants a longer hold time (often 15 to 30 minutes) to avoid lights switching off during periods of concentrated, low-movement work. A corridor or printer bay can use a much shorter interval. Sensitivity settings should be adjusted so that the sensor reliably detects the subtle movements of seated workers, not just people walking through. For KNX open-plan office lighting, daylight linking adds another layer of intelligence: a lux threshold tells the sensor to suppress artificial light when natural daylight is sufficient, reducing energy use without affecting comfort. Set this threshold based on measured illuminance at the workplane, not at the sensor itself.
Testing and fine-tuning occupancy logic on-site
Commissioning KNX presence detection does not end when the parameters are entered into ETS. On-site testing under realistic conditions is where the real calibration happens, and it consistently reveals edge cases that desk-based planning cannot anticipate.
Test each zone systematically: enter the space, confirm the lighting scene triggers correctly, then remain still at a workstation to verify the sensor maintains occupancy status during low-movement activity. Check zone boundaries by walking slowly along the edges of the detection area. Pay particular attention to the transition behaviour between adjacent zones: in an open-plan environment, a person moving from one zone to another should experience a seamless lighting response, not a momentary blackout. Adjust hold times and sensitivity iteratively until the system behaves naturally. Involve a building user in the final walkthrough if possible; their feedback often catches issues that technical testing misses.
Integrating presence-based lighting with KNX app control
Automated presence detection and manual control are not mutually exclusive. In fact, the most successful KNX office automation installations combine both. Giving facilities managers and end users a clear way to interact with the lighting system through a KNX app for smart building control builds confidence in the automation and reduces the temptation to override sensors physically.
Within the app interface, occupancy-based zones can be presented alongside manual scene controls, so a user can temporarily boost lighting in a zone for a presentation or suppress automatic switching during an after-hours event. It is worth configuring a “manual override” timeout so the system returns to automatic presence-based control after a defined period, maintaining the energy efficiency gains that KNX lighting commissioning is designed to deliver. Clear labelling of zones in the app, matching the floor plan annotations created during the mapping phase, makes the interface intuitive for non-technical users.
How xxter supports professionals with KNX lighting commissioning
xxter provides KNX system integrators with the tools to bring presence-based lighting systems fully to life, not just at the hardware level, but in the way end users experience and interact with the installation. The xxter controller sits at the centre of the KNX installation and connects all automation logic to a clean, intuitive app interface available on smartphones, tablets, and computers, with no licence fees or device limits.
For open-plan office projects specifically, xxter adds practical value in several ways:
- The xxter app lets facilities managers monitor and adjust lighting zones in real time, with clear zone labelling and scene controls that mirror the commissioning structure.
- The built-in scene module and trigger system allow integrators to build occupancy-driven logic, including time-based overrides and manual scene recall, without additional hardware.
- The planner function supports scheduled lighting behaviour alongside presence detection, useful for after-hours or cleaning scenarios.
- xxter’s Smart Energy Manager can complement presence-based lighting by integrating energy consumption data into a broader building efficiency strategy.
If you are commissioning KNX occupancy-based lighting in an open-plan office and want to explore how xxter fits into your installation, visit xxter.com or contact the xxter team directly for technical guidance and product information.
Vanliga frågor
How many KNX presence sensors do I typically need for an open-plan office floor plate?
There is no fixed ratio, but a practical starting point is to plan one sensor per structural bay or per cluster of 4–6 workstations, then adjust based on the manufacturer’s stated coverage area and the actual ceiling height. Overlapping coverage is preferable to blind spots, but excessive overlap can cause zones to trigger each other unintentionally — so always cross-reference sensor datasheets against your floor plan before finalising sensor positions. Budget for at least one or two additional sensors during the planning phase to cover any gaps revealed during on-site testing.
What is the most common mistake installers make when setting hold times in open-plan offices?
The most frequent mistake is applying a single, uniform hold time across all zones rather than calibrating each zone to its actual usage pattern. A short hold time that works well for a high-traffic corridor will cause frustrating light-offs at focus workstations where occupants sit still for extended periods. As a rule of thumb, start with 15–20 minutes for desk zones and 3–5 minutes for ancillary areas like corridors and printer bays, then refine these values during on-site testing with real users present.
How should I handle areas where natural daylight varies significantly throughout the day, such as zones near large windows?
For perimeter zones with high daylight variability, avoid setting a fixed lux threshold and instead consider using a dynamic daylight linking strategy where the threshold is measured at the workplane level rather than at the sensor. Some KNX presence sensors support continuous dimming linked to a lux setpoint, which allows luminaires to step down gradually as daylight increases rather than switching off abruptly — this delivers a much more comfortable experience for occupants. Re-measure and re-validate the lux thresholds across different times of day and seasons if possible, particularly at commissioning handover.
What is the best way to prevent 'ghost triggering' — where sensors detect movement outside their intended zone?
Ghost triggering is usually caused by sensors picking up movement through glass partitions, detecting HVAC air movement, or having overly broad sensitivity settings. Start by physically masking the sensor lens with the manufacturer-supplied masking strips to exclude problematic areas from the detection field, then reduce sensitivity incrementally until false triggers stop without compromising detection of seated occupants. It is also worth checking that sensors are not mounted directly above or near air conditioning vents, as thermal movement can trigger passive infrared (PIR) sensors reliably enough to keep zones permanently lit.
Can KNX occupancy-based lighting be integrated with a building's access control or booking system?
Yes, and this is increasingly common in modern office environments. KNX can receive external signals via a KNX IP interface or through a building management system (BMS) integration, allowing room booking data or access control events to pre-activate lighting scenes before occupants arrive. This approach is particularly effective for meeting rooms adjacent to open-plan areas, where scheduled occupancy is predictable. If you are working with a KNX controller like xxter, the planner and trigger functions can be configured to respond to these external inputs without requiring additional hardware.
How do I commission KNX presence detection in a space that is being phased into use — for example, where only part of the floor is occupied initially?
The best approach is to commission the full zone map and group address structure from the outset, but activate only the sensors and scenes relevant to the occupied areas. This way, the system can be expanded zone by zone without reworking the group addressing or ETS project structure. Document which zones are active at handover and leave clear notes in the ETS project for the integrator or facilities team who will bring additional zones online later. Using a KNX app with zone-level control also makes it straightforward for facilities managers to enable or disable zones as occupancy patterns evolve.
What documentation should I hand over to the client after commissioning KNX occupancy-based lighting in an open-plan office?
A thorough handover pack should include the annotated floor plan with zone boundaries and sensor positions, the ETS project file (backed up and version-labelled), a parameter log recording the hold times, sensitivity settings, and lux thresholds applied to each zone, and a simple user guide explaining how to interact with the system via the KNX app. It is also good practice to include a brief troubleshooting guide covering the most likely issues — such as lights not switching off or zones not triggering — so that facilities staff can resolve minor issues without needing to call the installer. A scheduled review visit at 4–8 weeks post-handover is strongly recommended, as real-world occupancy patterns often reveal fine-tuning opportunities that could not be anticipated during commissioning.