Rotary laser level: the site where it changes everything
What does a rotary do that a line laser does not?
It turns. Instead of a line thrown onto a wall, a mirror sends the beam round and describes a complete plane around the instrument. That plane is not visible over any distance — but a detector on a staff finds it and signals when it is on it.
The detector is what makes the reach: 250 m around the instrument, that is 500 m across. A line laser, by contrast, stops where the eye can no longer pick out the line: 20 m on our 360° models with 12 and 16 lines, 30 m on the 2-line cross.
On which sites does that count?
Wherever the level has to be the same at two points you cannot see together: setting out a terrace, a fence, footings, running a drainage fall down the length of a site, checking a slab. That is where range counts, not in a corridor.
Outdoors and in daylight the question does not even arise: a line laser’s line is invisible, and only a rotary with a detector gives a reading.
What are the five rotation speeds for?
To trade a bright point against a continuous plane, and that is the only trade that matters. Stopped, the beam stays a point you carry across by hand; at 600 rpm it forms a plane only a detector can read. The three speeds between spread that compromise out.
| Speed | What you get | Use |
|---|---|---|
| 0 rpm | a fixed dot | transferring an exact point, aiming at a staff |
| 60 rpm | a slow line, brighter to the eye | close work, indoors |
| 120 rpm | a compromise | everyday use |
| 300 rpm | a continuous plane | reading with the detector |
| 600 rpm | a continuous plane, the steadiest | long range, detector |
The logic: the slower the rotation, the longer the beam dwells in each place, so the brighter the dot is to the eye. The faster it turns, the more continuous the plane is for an electronic detector, which needs no brightness at all.
And the directional scan?
The instrument can limit its travel to a sector: 0°, 10°, 45°, 90° or 180°. The beam no longer spends time elsewhere, and the line becomes markedly more visible over the stretch you are working on. That is how you win back visibility to the eye without giving up rotation.
What is slope mode for?
The slope setting goes to ±5°. It is for anything that has to drain: a French drain, a ramp, a terrace, a garage descent. Our 3D and 4D models also have a slope mode, but over 20 m; the rotary holds the same slope over 250 m.
Do you need a rotary indoors?
No. In a room, a 360° instrument with 12 or 16 lines shows three or four planes at once, visible to the eye, and you work without a detector. The rotary only becomes the right tool when distance or light make the line unusable. It is a site instrument, not a room instrument.
What is in the box?
The instrument, the detector, the remote control, the glasses, the target, the case and the charger. The rechargeable battery is not included. Red or green beam, as you choose, horizontal or vertical mounting, with a stated IP54 rating. The detector is therefore in the box, not something to add.
Accuracy: ±20 arcseconds — what does that mean?
An angle, not a deviation. For an instrument used at a hundred metres that is the right way to write it: ±20 arcseconds give about ±1 mm at 10 m and ±10 mm at 100 m. What a stated accuracy is worth, and how to check it yourself, takes five minutes and a wall.
See also: the line laser outdoors, cross, 3D, 4D or rotary, and our rotary lasers.
- The detector makes the reach: 250 m around the instrument, 500 m across.
- Slow rotation = a bright dot for the eye; fast rotation = a continuous plane for the detector.
- Scanning over 10°, 45°, 90° or 180° concentrates the beam where you are working.
- Slope adjustable to ±5°, held over 250 m.
- Indoors a 360° with 12 or 16 lines is enough: the rotary is a site instrument.