The commissioning step that decides whether a PIR sensor earns its keep takes ten minutes and almost never appears on the datasheet: the walk test. Installation teams mount the sensor at the height in the manual, pair it, see the LED blink once, and move on. Weeks later the complaints arrive — the corridor near the door does not trigger, or the sensor fires whenever a truck passes the window — and every one of those outcomes was visible during a two-minute walk test on installation day.
What the LED actually told you
A single blink on pairing confirms the radio link, nothing more. It says nothing about whether the lens pattern covers the approach route, whether the mounting height puts the main lobe where the walking happens, or whether a heat source sits inside the cone. The walk test exists because PIR detection is a projection of a lens onto a room, and the only way to see that projection is to walk through it.
A proper test needs the sensor in its final state: final height, final angle, cover on (some housings attenuate the element noticeably), and the HVAC running at its normal duty, because vents move warm air and a draft that trips the sensor during the test is exactly the draft that will trip it at 3 a.m.
The walk itself
The standard sequence is three passes. First, walk the intended approach at normal speed and note where triggering starts and stops — the useful detection depth. Second, walk across the pattern's edge at half speed; slow lateral movement is the classic PIR miss, and where it fails tells you whether the unit needs re-aiming or a different lens. Third, stand still inside the pattern for a full minute: a sensor that fires on a stationary warm body has its hold-time or sensitivity misconfigured, and that fault is invisible in any pass-by test.
Record the results against the floor plan. A sketch showing where detection starts per pass turns a subjective impression into a document the customer signs, and it is the first thing to consult when a false-alarm or missed-event ticket arrives later.
What failures at test time actually mean
Most walk-test findings map to three fixes. A dead zone on the approach route is a height or angle problem — the pattern's main lobe sits above or below chest height, and 20 centimetres of re-aiming usually solves it. Missed slow lateral movement means the segmentation does not fit the route: a wide dome lens on a long corridor is the wrong shape, and a curtain lens solves it without touching sensitivity. Nuisance triggers from vents, windows or ducting mean the cone overlaps an environmental heat source, and the fix is re-aiming or masking, never a sensitivity slider — dropping sensitivity to silence drafts degrades detection of real intrusions at the same time.
None of these fixes are available after the customer has stopped paying attention. The walk test is when they are cheap.
What buyers should put in the handover document
For wholesale programmes the walk-test protocol belongs in the installation manual, not in the installer's head. Three lines cover it: the three-pass sequence with the pass speeds, a record sheet layout tied to the floor plan, and the acceptable result for each pass — a stated detection depth for the approach, a trigger on slow edge movement, and no trigger during the stationary minute. A manufacturer who supplies this as a template is telling you they have fielded commissioning complaints before and fixed them at the document level.
XingLiao manufactures PIR motion sensors as OEM/ODM programmes and ships walk-test protocols, masking options and lens variants matched to the deployment rather than a single default. Buyers can request the commissioning template alongside the sample.
The short version
Pairing confirms the radio; only walking the pattern confirms the sensor. Three passes — normal approach, slow edge, stationary minute — expose every fault that later becomes a support ticket, while the fixes are still free. Put the protocol in the manual and make the installer sign the sketch.
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