Duty Cycle (RTLS)
Duty cycle is the fraction of time a radio is active (transmitting or receiving) versus asleep. In a real-time location system (RTLS) tag, each blink, advertisement, or ranging exchange burns energy. Sleep between those events saves the cell. A tag that transmits once every fifteen minutes has a far lower duty cycle than a tag that reports every few seconds.
Plants care because brochure battery life almost always assumes a duty cycle. Motion wake, long advertising gaps, and sleep modes cut average current. They also cut how often the twin sees a location. Continuous path work, spaghetti charts, and utilization analytics need denser samples than rare heartbeats. The paired decision on power models and sample rate sits under battery life for RTLS.
Duty cycle is not the same as latency. Latency is how long one sample takes to land. Duty cycle is how often samples are attempted at all. A fast pipeline with rare blinks still looks empty on the map.
Key Components
Active window - The short interval when the radio transmits, receives, or ranges.
Sleep interval - Time between active windows when the tag draws microamps or less.
Motion wake - Firmware that raises duty cycle only after an accelerometer detects movement, then returns to sleep when idle.
Configured report rate - The planned blink or advertising interval while the tag is awake. This is the rate analytics will see if sleep does not intervene.
Keep-alive - A rare packet while stationary so the system still knows the tag exists, without continuous path detail.
Applications in Manufacturing and Logistics
Returnable tags on cages and totes often use low duty cycle so coin cells last years across thousands of units. Vehicle-mounted tablets and gateways usually run a higher duty cycle because they draw vehicle power. Yard trackers may mix rare heartbeats with motion wake so a parked trailer uses little energy until it moves. Indoor forklift tracking for path and industrial fleet management needs a duty cycle high enough that aisle turns and short stops stay visible.
When teams score RTLS options, they should put the duty-cycle assumption next to the analytics job. Gate presence and coarse search can live on rare events. Continuous hall analytics cannot. Cost traps from swap labour and thin data sit in what to include when calculating RTLS ROI.
Benefits and Challenges
Benefit: honest duty-cycle design stretches tag life and cuts cell-swap labour on large fleets. Challenge: silent duty-cycling hides behind multi-year life claims. Idle assets vanish from heat maps. Dwell understates parking. Paths break into dots. Ask for the wake policy and the awake report rate before you treat a battery slide as plant truth.
Related Terms
Data update rate is how often the twin stream changes. BLE advertising interval is one radio's configured gap between packets. Accelerometer motion wake is a common way to cut duty cycle. Latency is delay per sample, not how often samples exist. Beacons and battery tags sit inside these trade-offs.
Frequently Asked Questions
Does a lower duty cycle always mean a worse RTLS? No. Presence and search jobs can run on rare events. Continuous path and utilization jobs need denser samples. Match duty cycle to the decision.
Is motion wake the same as a 3–5 second sample rate? No. Motion wake only raises the rate while the asset moves. A parked load may send almost nothing. Spaghetti and dwell still need samples during idle stretches when those metrics matter.
Where do vendors hide duty cycle? In battery footnotes: motion detection enabled, report every fifteen minutes while still, or advertising far slower than the demo map showed.
How should we ask in an RFQ? Request life at the update rate you will enforce, with and without motion wake, for the tag form factor you will buy. Reject a life number that floats without those assumptions.