Topcon AT-B4A 24x Automatic Level
W-9 and vendor pack with every quote
Shipped direct from the manufacturer
Topcon builds the AT-B series in three levels. The AT-B4A is the 24x entry model, against the AT-B3A's 28x and the AT-B2's 32x. Its setting accuracy of 0.5 in. is shared with the AT-B3A, and Topcon states no baseline distance for it.
01
This is the AT-B4A, the 24x entry model in Topcon's three-level AT-B family, not the AT-B3A or the AT-B2
Topcon sells three automatic levels in the AT-B series. This one, the AT-B4A, is the entry model: 24x magnification, against 28x on the AT-B3A and 32x on the AT-B2. Setting accuracy, how tightly the compensator holds level once it has self-leveled, is 0.5 in. here, the same rating as the AT-B3A, and Topcon states no baseline distance for that figure. The AT-B2 is rated tighter, 0.3 in. Size and weight match the AT-B3A exactly: 122 by 214 by 140 mm, 1.5 kg. The AT-B2 runs slightly larger and heavier, 122 by 215 by 140 mm, 1.85 kg. If your job needs the AT-B2's tighter accuracy, this is not that level.
02
The AT-B4A focuses down to 20 cm from the telescope's own front lens, or 0.3 m from the instrument's center
Topcon states this limit two ways, from two different reference points on the same instrument. From the telescope's own front element, minimum focus is 20 cm, about 7.9 inches. Measured from the instrument's center instead, the same limit reads 0.3 m, about 11.8 inches. Both describe the same physical limit; they differ only in where the measurement starts. Work closer than that distance and the image will not resolve, whichever reference point you check it against.
03
Over a double-run kilometer of leveling, the AT-B4A holds 2.0 mm standard deviation without a micrometer
This is the figure that answers how accurate the level is in the field, not just how well it self-levels. Topcon publishes it on its AT-B series regional specification sheet: 2.0 mm (0.08 in.) standard deviation, for one kilometer of double-run leveling, without an optical micrometer fitted. A micrometer figure does not apply to this model on that sheet. Topcon's US brochure and its main catalog table do not carry this row at all; the regional sheet is the only place it appears. Treat this as the field-accuracy figure, separate from the setting-accuracy spec below, which measures how tightly the compensator itself holds level.
04
The compensator self-levels within plus or minus 5 degrees, and its working-range unit is unresolved between two sources
The AT-B4A's compensator is a pendulum type with magnetic damping, suspended on four wires chosen to resist thermal expansion. Set the instrument up within plus or minus 5 degrees of true level and it levels itself. Disturb the instrument mid-job and it relevels automatically, without operator input. Setting accuracy, how tightly it holds that level, is rated 0.5 in., the same as the AT-B3A, and Topcon states no baseline distance for it. Topcon's own catalog table prints the compensator's working range as plus or minus 15 feet. An independent dealer's own spec table states the identical row as plus or minus 15 arc-minutes instead, a different unit entirely. Neither source states a test condition. We have not picked a side, and you should check directly with Topcon before this figure decides anything for you.
05
It carries an IPX6 rating and runs from -20 degrees C to 50 degrees C, in a compact body
The AT-B4A is rated IPX6 under IEC 60529:2001, protected against powerful water jets from any direction and able to withstand a sudden shower or torrential rain. Operating temperature runs from -20 degrees C to 50 degrees C (-4 degrees F to 122 degrees F). The horizontal circle reads directly in 1-degree or 1-gon units, in a window below the eyepiece, and rotates freely so you can read any angle from zero. At 122 by 214 by 140 mm and 1.5 kg, it is a compact instrument.
06
Topcon publishes no warranty term for this level, and the box contents are not fully confirmed either
No Topcon document checked for this product line states a warranty length. Not the AT-B brochure, not the catalog table that carries every other AT-B4A spec on this page. Other product tables in the same catalog do carry a warranty row; this family's table does not. A five-year term is stated by dealers, not by Topcon, so treat it as a claim to confirm rather than a manufacturer fact. Box contents carry a similar gap. Topcon's own brochure lists the level itself, a hex wrench, a vinyl cover, a cleaning cloth, a manual and a hard case as key components. It scopes adjusting pins to the AT-B2 only. Two independent dealers list the same items except the vinyl cover, which neither one mentions. We are not printing a confirmed packing list here. Call us and we will tell you exactly what ships with your order before you buy.
07 FOR UNIVERSITIES, COLLEGES AND GOVERNMENT AGENCIES
My Surveying Direct ships the AT-B4A direct from Topcon, and institutions can order by purchase order
Universities, colleges and government agencies can order the AT-B4A by purchase order, with W-9 and tax-exemption documentation on file. A few things about this listing are not yet settled by Topcon, including the compensator's working-range unit and the exact warranty term. Call us before you order, +1 888 850 6533, Monday to Friday, 9 to 5 Mountain Time. We will confirm what your kit includes and where things currently stand before you buy.
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Institutions only: universities, colleges and government agencies.
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REFERENCE
Specifications
Optics
| Magnification | 24x |
| Field of view | 1°25', shared with the AT-B3A; the AT-B2 is 1°20' |
| Image | Erect |
| Stadia | Yes, 1:100 |
Minimum focus
| From the telescope's own front element | 20 cm (about 7.9 in.) |
| From the instrument's center | 0.3 m (about 11.8 in.), Topcon's own catalog-table figure for this row |
Leveling accuracy
| Standard deviation, double-run kilometer of leveling | 2.0 mm (0.08 in.) standard deviation for 1 km of double-run leveling, without a micrometer, per Topcon's own AT-B2/B3A/B4A regional specification sheet. A micrometer figure is not applicable to this model on that sheet |
Compensator
| Self-leveling range | ±5 degrees, the range within which the instrument can be set up off true level and still self-level |
| Setting accuracy | 0.5 in., shared with the AT-B3A. The AT-B2 is rated to a tighter 0.3 in. on the same table. No baseline distance is stated for this figure by Topcon |
| Working range, as printed by Topcon | ±15 ft., Topcon's own catalog-table figure for this row, printed identically for all three AT-B models |
| Working range, as printed by an independent dealer | ±15 arc minutes, from an independent dealer's own structured spec table for this same product. Not the same unit as Topcon's own catalog figure above. Neither source states a baseline or test condition. Not resolved |
| Compensator type | Pendulum compensator with magnetic damping, four suspension wires of super-high-tensile metal chosen for a minimal thermal expansion coefficient |
| Re-leveling | Automatic. If the instrument is disturbed on the job it relevels itself without operator input |
Build and environment
| Dust and water protection | IPX6 (IEC 60529:2001), protected against powerful water jets from all directions, withstands a sudden shower or torrential rainfall |
| Operating temperature | -20°C to 50°C (-4°F to 122°F) |
| Size | 122 x 214 x 140 mm, shared with the AT-B3A. The AT-B2 is a larger 122 x 215 x 140 mm |
| Weight | 1.5 kg, shared with the AT-B3A. The AT-B2 is heavier at 1.85 kg |
| Horizontal circle | Reads directly in 1 degree or 1 gon units, free rotation lets the operator read any angle from zero, readout window sits below the eyepiece |
Warranty
| Manufacturer warranty | Not published by Topcon. Neither the AT-B brochure nor the AT-B and B-series catalog table carries a warranty row for this product line, though other product tables in the same catalog do. A five-year term is stated by two independent dealers and is recorded here as unconfirmed by the manufacturer |