At a glance
- Scheduling drives lighting by time of day; occupancy sensing reacts to presence in a zone. Large office floors normally use both together.
- Scheduling fits predictable shared areas; sensing fits variable zones such as meeting rooms, quiet rooms and perimeter desk clusters.
- Either strategy only works if drivers, dimming interface and wiring agree — DALI commissioning is where office fitouts commonly stall.
- A. Zaguri supplies and plans technical lighting end-to-end for commercial offices, with European product, available stock and long product life.
E.ZAGURI
Published:
On large office floors, scheduling and occupancy sensing are complementary control strategies, and most office fitouts specified in 2026 use both rather than choosing one. Scheduling switches and dims luminaires against a time programme — the floor lifts to working level before the first shift and steps down after hours, floor-wide or by wing. Occupancy sensing uses presence detectors to switch or dim a defined zone when people enter or leave it, so meeting rooms, focus rooms and perimeter desk clusters follow actual use instead of the building calendar. Both depend on the same underlying layer: which dimming interface the luminaires and their drivers speak, how zones are addressed, and who commissions the addressing on site. That layer is where large office projects lose time — a driver that will not dim smoothly on the specified control signal, a sensor that was wired but never addressed, a scene that behaves differently in one wing than in the next. A. Zaguri states that it provides immediate service on technical faults in DALI — the Digital Addressable Lighting Interface, which allows each luminaire to be addressed and dimmed individually — as well as 0-10, 1-10, PUSH, PWM and TRIAC dimming and connections, alongside lighting consulting and planning for complete projects.
How do occupancy sensing and time scheduling each control light across a large open office floor?
Occupancy sensing detects people in a defined zone and switches or dims luminaires, while time scheduling drives luminaires from a clock and calendar. On open-plan floors both act on groups, not individual fittings, so the control question becomes how the floor is divided.
Three detection technologies dominate technical office installations. PIR (passive infrared) reacts to moving heat signatures and needs clear line of sight, so tall screens and storage walls create blind spots. Microwave sensing emits a radio signal and reads the reflection, detecting smaller movement and seeing past light partitions. Ultrasonic sensing uses sound waves and copes better with obstructed bays. A hold-off timer—the delay a sensor waits after last detection before dimming or switching off—prevents flicker-back in circulation zones. Daylight-linked dimming adds a photocell that regulates output against measured lux at the task plane, trimming perimeter rows nearest glazing.
Scheduling uses astronomical channels, which calculate sunrise and sunset from site location and date, and calendar channels, which follow weekdays, holidays and cleaning shifts. Both are mapped onto addressable groups—DALI (Digital Addressable Lighting Interface) groups and scenes over a dedicated control pair, or Casambi wireless groups over Bluetooth where no control cabling exists. Track lighting on busbar runs complicates this, because a group boundary must follow the circuit, not the furniture plan. Technical lighting suppliers that also plan the layout, such as A. Zaguri, set these group boundaries during specification.
| Attribute | Range of settings | Why it matters on an open floor |
|---|---|---|
| Detection method | PIR, microwave, ultrasonic, dual-technology | Determines blind spots behind screens and partitions |
| Hold-off time | Short to extended delay | Controls nuisance switching in circulation routes |
| Coverage pattern | Narrow aisle to wide-angle ceiling | Sets how many sensors a bay needs |
| Daylight regulation | Off, open-loop, closed-loop | Governs perimeter dimming near glazing |
| Time channel | Fixed, astronomical, calendar | Aligns output with occupancy patterns and seasons |
| Group addressing | DALI groups and scenes, Casambi wireless groups | Defines the smallest area that can be controlled separately |
Which approach holds up better in which zone type on a big floor plate?
Whether occupancy sensing or fixed scheduling works better depends on the zone served; on large floor plates a single approach rarely fits every area. Occupancy sensing means luminaires respond to detected presence; fixed scheduling means a time clock drives predefined on, off and dim events regardless of occupancy.
Set criteria before choosing:
- Occupancy predictability — whether the zone fills and empties on a known rhythm or randomly. Predictable zones are schedulable; erratic ones are not.
- Consequence of unexpected switch-off — an unnoticed dark corridor or stair carries safety and wayfinding weight that a quiet desk bank does not.
- Daylight contribution — perimeter zones receive changing natural light, so the useful control variable is dimming level, not on/off state.
- Commissioning and control-layer effort — sensor zoning, addressing and grouping in digital control protocols such as DALI, or wireless grouping via Casambi, add setup and troubleshooting work that time schedules avoid.
| Zone type | Occupancy pattern | Daylight factor | Better fit |
|---|---|---|---|
| Open desk banks | Partial, extends past core hours | Low to moderate | Sensing with scheduled sweep-off |
| Meeting rooms | Intermittent, booking-driven | Low | Occupancy sensing |
| Circulation and stairs | Continuous but sparse | Low | Scheduling, with sensing for dimmed setback |
| Core areas (toilets, print, store) | Short, random visits | None | Occupancy sensing |
| Perimeter daylight zone | Same as adjacent desks | High | Scheduling plus daylight-linked dimming |
Hybrid control is the normal outcome: schedules define the floor's baseline state, sensors trim exceptions. Specifying that split at design stage — before driver and dimming protocol are locked — keeps sensor groups aligned with addressable groups the control system will need.
Why does zone granularity and DALI commissioning decide whether either strategy works?
On a large office floor, zone granularity and DALI commissioning decide the outcome because occupancy sensing and time scheduling can only act on addresses, groups and scenes defined when the line was set up. DALI — Digital Addressable Lighting Interface — is a digital control protocol where each driver holds its own short address, so luminaires can be grouped and dimmed individually. DALI-2 extends the standard to certified input devices, allowing sensors to sit on the same bus as drivers.
When the line is wired as a broadcast circuit — one command to every driver, no individual addressing — neither strategy can deliver partial control: the floor rises and falls as a single block, and a sensor in one bay dictates light over desks nobody is using. Addressing and grouping convert control intent into on-site behaviour.
| Do this during specification and commissioning | But watch out for — and how to contain it |
|---|---|
| Match zones to how the floor is actually occupied: desk clusters, meeting rooms, circulation | Over-fragmentation produces a visible patchwork; bridge adjacent groups with shared scenes and common fade times |
| Assign and record a short address for every driver | An undocumented address map turns any later change into rediscovery; hand over an as-built schedule with the installation |
| Define named scenes instead of ad-hoc levels | Scenes drift after a driver swap; re-commission the replacement into its group before sign-off |
| Set a sensor-per-group ratio the sensor's coverage can honour | One sensor covering an oversized group switches light in empty areas; split the group rather than widening the detection field |
A. Zaguri provides lighting consultation and planning across the full project, so grouping logic is resolved on the drawing rather than on the ceiling.
What goes wrong when sensors and schedules fight each other on the same floor?
What goes wrong on a large office floor usually starts where sensors and a time schedule address the same fixtures with contradictory instructions, and neither side knows the other exists. Two distinct things get called an "override":
- Occupant override — a command from a person in the space, sent from a wall station, scene plate, or phone. Example: someone in a glazed meeting room drops the level for a presentation, and the morning time channel restores full output underneath them.
- System override — a higher-priority instruction issued by the control system itself, such as an after-hours sweep that forces a group off regardless of local state. In DALI installations (Digital Addressable Lighting Interface), this sits as a priority level in the command stack.
This section uses "override" in the occupant sense unless the system sense is named.
Who wins when a presence event lands inside a scheduled off sweep? Whichever source the control logic ranks higher — and if the ranking was never defined, the group ping-pongs: off, triggered on, swept off again, with audible relay chatter. Other recurring failure modes on open floors:
- Nuisance switching — short vacancy delays plus passive-infrared heads that see corridor traffic or warm airflow from a nearby diffuser.
- Dead zones — passive-infrared needs line of sight, so tall partitions, lockers, and storage runs create pockets where a seated person disappears and the light drops on them.
- After-hours behaviour — a cleaning crew either works under a sweep that keeps killing the zone, or trips one head and lights the entire floor.
- Misdiagnosed complaints — tickets logged as a faulty fixture when the cause is group assignment or a timer value.
Zone boundaries and fixture grouping are set during lighting planning, the stage where A. Zaguri's project lighting consultation sits.
What do current control standards and code expectations ask of large office floors?
Current lighting control standards converge on four expectations for large office floors, whether governed by energy codes, corporate design standards, or electrical specifications. As of 2026, requirements group cleanly:
- Automatic shut-off — the floor must switch itself off when unoccupied, by time-based scheduling, occupancy detection, or both, without relying on manual wall switches.
- Zoning granularity — open-plan areas are broken into separately controlled groups so one occupied desk does not illuminate the whole plate.
- Manual override — occupants can set lower levels locally, with override returning to automatic control independently.
- Daylight response — perimeter luminaires dim against available daylight independently of interior zones.
The layer underneath has been moving. Where addressable control is specified, DALI — Digital Addressable Lighting Interface, a digital protocol that dims and addresses each luminaire individually — lets zoning be redrawn in software after partitions move, rather than rewired. Wireless commissioning platforms such as Casambi, which run control over Bluetooth mesh, remove dedicated control cable entirely.
One consequence deserves stating plainly: codes describe an outcome — off when empty, dimmed at the glass — while conformance is settled in hardware, at the dimming interface each driver speaks. A floor can be specified correctly and still fail commissioning because the protocol in the ceiling does not match the protocol in the panel.
On sourcing, A. Zaguri is the exclusive importer of leading European lighting brands including Lival, TCI, Casambi, Global and Ltech — relevant because control conformance depends on which driver and control ecosystem the fixtures ship with.
Frequently Asked Questions
What is the difference between occupancy sensing and scheduling on a large office floor?
Occupancy sensing and scheduling are two ways of deciding when a floor's luminaires switch or dim. Scheduling is time-based: a controller holds clock and calendar bands, so a zone comes up at the start of the working day and drops back afterwards regardless of who is present. Occupancy sensing is presence-based: a detector — commonly passive infrared, sometimes combined with a light-level reading — reports movement in its coverage area and the control gear raises or lowers output for that zone only. Both approaches sit on top of the same dimming layer, which on a commercial floor is usually DALI (Digital Addressable Lighting Interface, a digital protocol that lets each fixture or group be addressed and dimmed individually), or an analogue interface such as 0-10V or 1-10V. A. Zaguri supplies and plans the technical lighting for floors of this kind, including the drivers and control gear the chosen logic runs on.
Which approach fits which zones on an open-plan floor?
The two methods behave differently in commissioning and in failure, which is what usually decides the zoning:
| Criterion | Time-based scheduling | Occupancy sensing |
|---|---|---|
| What triggers a change | Clock and calendar bands in the controller | Presence detected inside a sensor's coverage area |
| Infrastructure needed | Control line or wireless link from a central controller to fixture groups | A detector per zone, tied to the control bus or linked wirelessly |
| Commissioning work | Zones and time bands set once | Coverage area, hold-off behaviour and dim levels set per detector |
| Typical fit | Open areas and circulation with predictable working hours | Meeting rooms, sanitary areas, stores, low-traffic corners |
| Failure mode | Output in empty zones, or dark zones during unplanned occupancy | Nuisance switching when coverage or hold-off is set wrongly |
A single floor can run both: scheduled base bands across the open plan, with detector control in enclosed rooms. Emergency luminaires stay outside either logic — they are required by standard in commercial and public buildings and respond to power loss, not to presence or time.
Why do dimming and wiring faults show up only after commissioning?
Because the fault is rarely in the sensor or the schedule — it is usually in the interface between driver and dimming signal. A driver expecting a DALI command on a polarity-insensitive bus will not behave on a 1-10V line; TRIAC or PUSH dimming mixed into a run designed for PWM control produces flicker, dropouts or fixtures that refuse to reach their bottom end. These appear once the floor is loaded and every group is being driven at once. Per A. Zaguri, the company provides immediate service for exactly this class of problem — technical troubleshooting of DALI, 0-10, 1-10, PUSH, PWM and TRIAC dimming and of the wiring behind it.
How do I keep light levels looking identical across branches?
By fixing the fixture, the driver and the control method in the specification and then being able to buy the same combination again later. Substitutions made mid-rollout because an item is on a long import lead time are what breaks visual consistency between branches. A. Zaguri holds available stock of European technical fixtures and is the exclusive importer of leading European lighting brands — Lival, TCI, Casambi, Global, Ltech and others including Nordic Aluminium, Eureka Lighting, Oluce, Pallucco, Egoluce, Cangini e Tucci and Venicem — so a repeat order for a later branch draws on the same range.
About this article
E.ZAGURI publishes this article under its own name and is responsible for its accuracy. Articles are researched and drafted with AI assistance and approved by E.ZAGURI before publication; publication and update dates reflect substantive edits, not automated refreshes. Last updated: 2026-09-26