Comparison Bosch GLL 2-20 Professional 0601063J00 vs Bosch GCL 2-15 Professional 0601066E00

General purpose of the device.

This parameter is indicated for models that have a clear specialization - these are mainly laser levels, including rotary ones. Among such devices, there are the following application options: for the 360° area, only for point projections, for the floor and for pipes. Here are the features of each of these varieties:

— For 360° area coverage. A full circle, 360°, by definition covers all rotary levels (see “Type”). However, such specialization can also occur in “regular” laser models. In such devices, full 360° coverage is achieved in other ways - usually by the presence of several emitters, each of which covers its own sector, or a special prism that scatters the beam from one emitter over a full 360°.

- Point projections only. Levels with this feature do not form marks in the form of lines during operation and “draw” only points. At the same time, in the simplest models there is only one point projection, but devices with several marks (up to 5) are more common. In any case, such devices are intended for relatively simple work where there is no need for marking along lines.

- For the floor. Levels designed for working with floors - screeds, laying coverings, etc. A common feature of such devices is a fairly wide base, which allows, in fact, to place the device di...rectly on the floor. But the specific design and operating features of levels of this type may be different. Thus, devices with a characteristic layout are quite popular - with two vertical projections intersecting at an angle of 90° (some models provide two more projections directed in opposite directions from the main ones). Such a device can be used not only on the floor, but also on walls: if you press its base tightly against a particular surface, it will form two clearly perpendicular lines on it. In the case of floors, this can be convenient, for example, when laying tiles.
Another common type of floor level is devices designed to detect unevenness. To do this, use a line formed on the floor using a vertical projection. During operation, a level placed on the floor and aligned horizontally rotates around a vertical axis, and the line “scans” the floor; when it hits a ledge, it becomes uneven. Note that in the simplest models, such a “scanner” uses only one projection, but there is also a more advanced version - a line created by two projections at once. Such a pointer, when it hits an uneven floor, is divided into two separate lines - this is much more noticeable than the deviation when using a single projection.

- For pipes. A rather rare type of specialized laser levels are devices for laying pipelines. They are used, in particular, in the construction of water supply, sewer and stormwater systems. Pipe levels most often have a characteristic cylindrical shape, with a handle at one end and a point laser emitter at the other. They are installed horizontally on special legs (the kit usually comes with several sets of such legs, varying in height); the design usually has a self-leveling mechanism with quite extensive capabilities; and the necessary measurement accuracy is ensured by a target with special markings. Such devices allow you to at least accurately lay horizontal lines, and many of them also allow you to work with corners.

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.

The temperature range at which the device is guaranteed to work for a sufficiently long time without failures, breakdowns and exceeding the measurement error specified in the characteristics. Note that we are talking primarily about the temperature of the device case, and it depends not only on the ambient temperature — for example, a tool left in the sun can overheat even in fairly cool weather.

In general, you should pay attention to this parameter when you are looking for a model for working outdoors, in unheated rooms and other places with conditions that are significantly different from indoor ones; in the first case, it makes sense to also make sure that there is dust and water protection (see "Protection class"). On the other hand, even relatively simple and "myopic" levels / rangefinders usually tolerate both heat and cold quite well.

The standard size of the thread used to mount the level/rangefinder on a tripod (if available). This option can be useful if you already have a surveying tripod that you want to use with the tool.

The most popular options in modern devices are 1/4" and 5/8". It is worth noting that 1/4" is a standard size for photographic equipment - accordingly, levels with such a thread can be installed even on ordinary photographic tripods.

The ability to automatically turn off the device after a certain time. This function is found in those types of measuring instruments that require power for operation — first of all, we are talking about laser rangefinders, however, this list may also include levels (see "Type"), both laser and optical with additional digital modules . The main purpose of auto-shutdown is to save electricity: after all, almost all such devices have autonomous power sources (see "Power"), the charge of which is not infinite. Forgetting to turn off the device, you may encounter an unpleasant situation: the batteries are dead, but there are no fresh ones at hand; auto-off prevents these situations and generally increases the operating time without changing batteries or recharging the battery. In addition, this feature is also useful from a safety point of view: automatic laser shutdown reduces the likelihood that its beam will accidentally fall into the eyes of someone around (including a forgetful operator).

In some models, auto-shutdown works on the entire electronics, in others it may be possible to turn off the laser first (as the most energy-intensive and unsafe part), and only after a while — all other electronic circuits.

The time after which the device turns off by itself completely if the user does not perform any action.

See above for more information on auto power off; and his time has a double meaning. On the one hand, if this time is short, then the idle time of the device will be minimal, which helps to save energy. On the other hand, too frequent auto-shutdown (with subsequent switching on for work) is also undesirable — it increases the wear of components and reduces the resource, and it is not always convenient for the user. So manufacturers choose the time, taking into account the balance between these moments, as well as the general class and purpose of the device. So, in some rangefinders, this indicator does not even reach a minute, although in most such devices it is in the range from 3 to 8 minutes; and in some professional devices (primarily levels), the auto-off time can be 30 minutes or more (up to 3 hours).

The wavelength of the radiation emitted by the LED of the level or rangefinder; this parameter determines primarily the colour of the laser beam. The most widespread in modern models are LEDs with a wavelength of about 635 nm — at a relatively low cost, they provide bright red radiation, giving a well-visible projection. There are also green lasers, usually at 532 nm — the marks from them are even better visible, but such LEDs are quite expensive and rarely used. And radiation with a wave longer than 780 nm belongs to the infrared spectrum. Such a laser is invisible to the naked eye and is poorly suited for leveling, but it can be used in rangefinders — of course, with a viewfinder (see "Type" for more details).

The sweep angle in the horizontal plane provided by the level emitter. If there are several emitters, their total coverage angle is indicated here; a typical example of such devices are models for full 360 °, not related to rotation.

Actually, all rotary devices, by definition, provide a coverage of 360 °. Therefore, it is worth paying attention to this parameter in cases where we are talking about more traditional laser levels. And here it is worth considering that a larger coverage angle, on the one hand, can provide additional convenience, on the other hand, it increases the price and power consumption of the device. So when choosing, you should proceed from real needs; detailed recommendations on this subject can be found in special sources.