Comparison Bosch GOL 20 D Professional 0601068402 vs Intertool MT-3010

The range at which the device remains fully operational without the use of additional receivers (see below); in other words, the radius of its action without auxiliary devices.

In some models, a range may be specified that shows the minimum ( 3 cm, 5 cm) and maximum measurement ranges. But in most cases, only the maximum value is indicated.

The specific meaning of this parameter is determined by the type of instrument (see above). So, for optical levels, the measurement range is the greatest distance at which the operator can normally see the divisions of a standard leveling staff. For laser levels, this parameter determines the distance from the device to the surface on which the mark is projected, at which this projection will be easily visible to the naked eye; and in rangefinders we are talking about the greatest distance that can be measured. Typically, the measurement range is indicated for ideal conditions - in particular, in the absence of impurities in the air; in practice, it may be less due to dust, fog, or vice versa, bright sunlight "overlapping" the mark. At the same time, tools of the same type can be compared according to this characteristic.

Note that it is worth choosing a device according to the range of action, taking into account the features of the tasks that are planned to be solved with its help: after all, a large measurement range usually significa...ntly affects the dimensions, weight, power consumption and price, but it is far from always required. For example, it hardly makes sense to look for a powerful laser level at 30-40 m if you need a device for finishing work in standard apartments.

Accuracy is described as the maximum deviation from the true value of the measured parameter, which the device can give if all the rules for its operation and the corresponding measurements are observed. In both rangefinders and levels, this parameter is usually designated for a certain distance — for example, 3 mm at 30 m; but even for one manufacturer, these "control" distances may be different. Therefore, in our catalog, the accuracy of all devices is recalculated for 1 m distance; with such a record, for the example above, it will be 3/30 \u003d 0.1 mm / m. This makes it easier to compare different models with each other.

It is also worth mentioning that the meaning of the "accuracy" parameter for different types of measuring instruments (see "Type") will be different. For optical levels, it is described in the "SKP" paragraph above. For laser levels of all types, accuracy is the maximum deviation of the mark from the true horizontal (or vertical, if such a function is provided), and for the horizontal, we can talk about both moving the mark up / down and turning it. In rangefinders, this characteristic describes the maximum difference (both in "plus" and "minus") between the readings of the device and the actual distance to the object.

Anyway, the smaller the error, the better; on the other hand, accuracy significantly affects the price of the device. Therefore, it is necessary to choose a specific model for this parameter, taking into account the...specifics of the planned work. For example, for a relatively simple repair in a residential apartment, a high-precision tool is unlikely to be required; and recommendations for more complex tasks can be found in specialized sources, ranging from expert advice to official instructions.

Measuring accuracy provided by a laser distance meter (see "Type")

This parameter is traditionally indicated by the error - the maximum deviation of the obtained results from the actual values, which may occur due to the imperfection of the device. The physical features of laser rangefinders are such that in such devices the error is practically independent of the measured distance. Therefore, the accuracy of such rangefinders is indicated in millimeters. At the same time, in our time, models are generally considered to be high- precision, where this indicator does not exceed 1.5 mm (in some models it is only 1 mm); but even in relatively simple and inexpensive devices, deviations of more than 3 mm are practically not encountered.

The general selection rules for this indicator are traditional: the more accurate the device, the more expensive it is, as a rule. In addition, we emphasize that for everyday and even many professional tasks, the difference described above is not fundamental in accuracy. Therefore, it makes sense to specifically look for a rangefinder with a minimum error in the case when the measurement accuracy “to the millimeter” is fundamental. At the same time, it should be borne in mind that for such measurements, appropriate accuracy in the placement and use of the device itself will be required - otherwise, all the advantages will be nullified by errors from incorrect installation and operation.

The diameter of the lens of the optical level (see "Type"). First of all, the aperture ratio, the amount of light transmitted by the optical system, depends on this parameter. The larger the lens diameter, the higher this number and the brighter and clearer the image visible to the operator is, which is especially important in low light conditions (in cloudy weather, at dusk, etc.). In addition, a large lens allows you to increase the angle of the field of view; for more on this, see p. "Magnification".

The root mean square measurement error that occurs during the operation of an optical or digital level.

This indicator is noticeably lower than the deviation indicated in the “Accuracy” paragraph: if the accuracy is indicated in millimeters per meter, then the SKP is in millimeters per kilometer (more precisely, the so-called “double-track kilometer” - a route 500 m long, traveled there and back). There are no contradictions here: the SKP describes exclusively the error caused by the imperfect design of the device itself and arises under absolutely ideal measurement conditions, while the accuracy characterizes the “level-staff” system and describes deviations that are relevant for real conditions. Therefore, SKP as a whole is a formal parameter used to divide levels into accuracy groups - high-precision, precision and technical. The first category includes devices with SCP up to 1 mm/km, the second - up to 3 mm/km, and the third - all less accurate. The minimum accuracy groups required for certain types of work are described in special sources - in particular, regulatory documents and instructions.

The smallest focal length of an optical or digital level (see "Type").

The focal length in this case means the smallest distance to a leveling staff or other object at which the device can clearly focus on it. In most modern levels, this distance does not exceed 1.5 m, and in some models it is about 20 cm at all. So, from a practical point of view, this is more of a reference than a really significant parameter — after all, such devices are used at much greater distances. At the same time, with similar basic characteristics, a shorter focal length, usually, means more advanced and high-quality optics.

The width of the field of view provided by the lens of an optical or digital level (see "Type").

According to the general laws of optics, an increase in the magnification factor leads to a decrease in the angle of view; however, models with the same multiplicity may differ in this indicator. At the same time, on the one hand, the more extensive space the operator sees, the more convenient it is to work with the device, especially in the process of aiming at a leveling staff or other specific target. On the other hand, the difference between specific options is small and in fact it rarely turns out to be fundamental. A typical example: most 24x levels have an angle of view from 1° 20' to 1° 30', which at a distance of 100 m corresponds to a visible space diameter of approximately 2.32 m to 2.61 m. As you can see, the difference in diameters is only about 29 cm, and at shorter working distances it decreases proportionally.

Thus, from this point of view, the viewing angle is more of a reference than a really significant parameter during operation. At the same time, it is worth noting that a wider field of view is often a sign of a more advanced instrument, which, in particular, has a larger lens — and this feature has quite practical advantages (for more details, see "Lens Diameter").

The working range of the compensator installed in the level.

A compensator is a device for smoothing out small deviations of the device installed in the working position. This function is especially important for optical and digital models, in which it is mainly used. Do not confuse it with auto-leveling: the latter is used during the initial installation of the level, and the compensator absorbs small shocks that occur already in the process of work (a typical example is ground vibration from heavy construction equipment nearby). And the range is indicated by the maximum deviation from the horizontal, which such a mechanism can eliminate.

These values in modern levels are small, they are calculated in arc minutes and usually range from 12 – 15' to 30'. At the same time, the wider the range of the compensator, the more efficient it is, the stronger shocks and vibrations it can smooth out; on the other hand, increased efficiency inevitably comes at a price. Also note that compensators can differ in the type of damper (see below).

The type of damper that the level compensator is equipped with.

Let us remind you that compensators are used to protect a device installed horizontally from small shocks and vibrations (for example, on unstable soils or near heavy construction equipment). And the damper represents the “heart” of the compensator - the mechanism directly responsible for alignment; The basis of such a mechanism is a pendulum, which is vertical when the device is stationary and begins to swing when it deviates from the horizontal. To return the level to its working position, you need to stop this pendulum; Different types of dampers differ precisely in the method of braking, the options here can be as follows:

- Magnetic. Braking is carried out due to the field from a permanent magnet. Each time the pendulum passes by such a magnet, the swing slows down until it stops completely.

- Airy. It would be more correct to call this method “weight-based”: to operate the compensator, a massive load is used, attached to the lower part of the pendulum.

By themselves, both described principles have no fundamental differences in either accuracy or efficiency. It is believed that an air damper is better suited for high-precision levels, and a magnetic damper for less precise devices (with so-called technical accuracy); however, in practice everything depends on the overall quality of workmanship of a particular device.