Comparison Forte LDM-30-3S 83911 vs Crown CT44028

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.

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 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).

takes no action.

This parameter is relevant primarily for laser rangefinders. This is due to the fact that in such devices the laser is one of the most “gluttonous” (in terms of power consumption) components, moreover, it is used only directly in the measurement process. Therefore, along with auto-shutdown of the device itself (see above), such devices can also provide auto-shutdown of the laser — mainly as a “safety” function in case the user himself forgets to turn off the emitter. The time of such an auto-shutdown usually does not exceed a minute — one and a half, although there are exceptions.

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).

Own screen on the device body.

All displays are used to display various additional information, which makes control more convenient and clear compared to models without displays ; but the specific functionality and features of the screen may vary, depending on the type. There are black and white options, backlit displays, color and even touch screens. More details about each:

— B/W without backlight. The simplest and most inexpensive type of display: a black-and-white LCD sensor without its own backlight. Despite their overall simplicity, such screens can have quite extensive capabilities: technically, they can display data related to the operation of the device (for example, the results of rangefinder measurements), and other additional information, including quite specific ones. In fact, the only thing that b/w displays are not suitable for is displaying images from a digital camera. In practice, the functionality of the display is selected according to the capabilities of a particular device. As for the lack of backlighting, this feature makes it difficult to use in low light conditions, but it reduces the price and power consumption. In addition, under the sun or other bright lighting on advanced backlit screens the image may “fade”, while on the simplest black and white screens wi...thout backlight it, on the contrary, becomes even clearer.

— B/W with backlight. Black and white screens equipped with backlight systems. Note that this category actually includes two types of displays: traditional black-and-white LCD matrices in the “black image on a white background” format, supplemented by an external lighting system, as well as single-color screens in the “light image on a black background” format, where the light itself can glow. image. Be that as it may, such displays can be used without restrictions in low light, but the downside of this is increased power consumption - especially in models where the backlight is constantly on.

- Colored. The functionality of color displays can be different - from the simplest LCD screens, capable of displaying only a few primary colors (for example, highlighting the most important numbers on the screen in a different color), to full-color matrices (like tech used, for example, in laptops). The first type is somewhat more convenient and clearer than the b/w displays described above, costs a little more, but has no other differences. The most advanced color screens, in turn, can even display a picture from a digital camera - and, in fact, they are mainly used in devices equipped with such cameras.

- Touch. The most advanced type of display. Such screens are almost always made in color and equipped with backlighting, and touch controls also allow them to be used to control the device (similar to what happens in smartphones and tablets). In terms of control, touch screens are more convenient and intuitive than traditional panels with buttons, switches, etc.; they are much better suited to handle the abundance of functions, and also provide some additional capabilities that are not available with traditional controls. On the other hand, such equipment is not cheap, and it simply does not make sense to use it in relatively simple and inexpensive devices - for such models, more affordable displays, even the simplest black and white ones, are quite sufficient. Therefore, the presence of a touch screen is almost guaranteed to be a sign of a high-end device with an abundance of functions.

Level based on a spirit capsule (or several such capsules) built into the body of the instrument.

Such a device allows you to control the position of the device — namely, to check whether it is set horizontally; however, some models also provide levels for the vertical position, and sometimes even for tilting at 45 ° or another angle. But the specific purpose of the spirit level may be different, depending on the type and general level of the device. The most popular option is a preliminary, rough installation of the laser level in the horizontal: the initial adjustment is carried out manually using a level, and after that the built-in self-leveling mechanism is activated. In simple and inexpensive household levels where high accuracy is not required, the spirit chamber may even be the only way to set it to the desired position; and some of these devices can also be used as full-fledged building levels.

The functions of the rangefinder allow you to more comfortably perform work and not calculate various mathematical formulas, but with one button to get the result after the measurements have been taken. Among such assistants there are area / volume measurement, indirect measurements (Pythagorean theorem), tilt angle measurements, height measurement, trapezoid measurement, addition / subtraction, min. / maximum values, continuous measurement (tracking), countdown timer, layout mode, painter mode, memory of the last measurements and others. More about them:

— Measurement of area/volume. Built-in software tool for measuring the area and / or volume of premises or large objects. This function works as follows: the user only needs to measure the length, width, and for volume, also the height of the object, after which the rangefinder will independently multiply the received data and display the final result.

— Indirect measurements (Pythagorean theorem). A function that allows you to determine the length of one of the sides of a right triangle from its othe...r two sides. One of its most popular uses is to measure the height of buildings, walls, poles, and other objects without having to approach them. To do this, you need to place the rangefinder at ground level and measure two distances from this point: to the foot of the object, horizontally (one of the legs) and to the top of the object (hypotenuse). Based on the Pythagorean theorem, the device will automatically calculate the length of the second leg - that is, in this case, the measured height.

— Measuring the angle of inclination. A feature that turns the rangefinder into an advanced level. When it is turned on, it is enough to attach the device with its side to an inclined surface or other similar object - and the built-in sensor will automatically determine the angle of inclination, displaying it on the display.

- Height measurement. A special mode for measuring the height of various objects. Note that in many devices this function is actually performed by indirect measurements according to the Pythagorean theorem (see above). Therefore, the possibility of measuring height is indicated mainly in tech models that have more advanced capabilities for such measurements. A typical example is an extended version of the Pythagorean theorem, which is used when a rangefinder is mounted on a tripod at a certain height from the ground. With this placement, to measure the height, you need to take three measurements: the distance to the foot of the object (the rangefinder will be tilted down), to the object horizontally and to its top. According to the data received, the device will build two triangles, perform the necessary calculations and give the final height value.

- Measuring the trapezoid. A function that allows you to determine the length of the fourth side and the total area of the figure from three sides of a rectangular trapezoid. It is mainly used to calculate the area of walls and facades in houses with sloped, gable and other similar roofs. If the upper part of the wall has a slope to one side, to determine the area, it is enough to measure the length of the base and the height of the two sides adjacent to the edges of the roof. If the upper part of the wall adjoins a gable roof, the wall must be divided into two trapeziums and measured using the same procedure; a similar method can be used with roofs of more complex shape, due to which the upper side of the wall looks like a broken line.

- Addition / subtraction. Possibility to sum the results of measurements, as well as to subtract one result from another. One of the simplest computing functions - which, nevertheless, can make life much easier for the user.

— Min. / maximum values. In this mode, the device takes a whole series of measurements at a short interval, and then displays the smallest or largest of the obtained values. As a rule, modern rangefinders provide for both formats of operation (both minimum and maximum), which is why they are combined into one function. However, the meaning of these options is different. So, the maximum value allows, among other things, to accurately determine the size of the room: it is enough to place the device in the corner, turn on the appropriate mode and slowly draw the laser horizontally in the region of the opposite corner; the largest distance obtained will be the length of the size. In turn, the minimum value can be useful, for example, to measure the length of the perpendicular to the wall; the measurement technique here is similar, and the smallest number obtained will just correspond to the length of the perpendicular.

— Continuous measurement (tracking). In this mode, the device continuously takes measurements at a sufficiently high frequency (usually 1 - 2 times per second), displaying the corresponding results on the display. This format of work is also called "roulette mode", it allows you to constantly track the distance from the rangefinder to a specific object. This can be useful, for example, if you need to accurately measure the distance from a wall, pole or other landmark: instead of taking several measurements, trying to “get” the device into the right position, just turn on tracking and move the rangefinder until the desired distance value is not displayed.

- Countdown timer. A function that allows you to automatically take measurements after a specified period of time. A kind of analogue of shooting on a timer in cameras: just point the device at the desired point, turn on the countdown - and at the end of it the device will work itself. The countdown is mainly used to eliminate the twitching of the body, which inevitably occurs when measuring manually (at the touch of a button); this is especially useful for high precision measurements and/or when using the instrument from a tripod or other stand.

- Markup mode. A mode that allows you to divide a particular segment into sections of a certain length - for example, under posts for a fence. The specific implementation and capabilities of this mode may be different, these nuances should be clarified in the instructions for a particular device. So, in some devices, you can measure the total length of the segment, set the number of identical sections - and the electronics will calculate the length of each part. In others, you can manually enter the length of the segment, or even several options for their length at once (for example, the distance from the starting point to the first mark and further gaps between marks). In any case, in the marking mode, the rangefinder works in the same way as the tracking described above - constantly taking measurements and displaying the current result on the display. And when measuring, the device must be smoothly moved along the marked line; when the next mark is reached, a signal will be given.

- Painter mode. A mode designed to calculate the total area of walls (internal in the room or external in the entire building). Such an opportunity is especially convenient for painting work (hence the name), as well as other similar tasks - wallpapering, laying tiles, external insulation, etc. The “painter mode” is implemented, as a rule, as follows: using the device, the master first measures the total perimeter of the walls, then their height (or vice versa), after which the electronics automatically calculates and gives the final value.

— Memory of the last measurements. The ability to save the results of the last few measurements in the memory of the device. In most models with this function, the memory of the last measurements is included initially, the user does not need to specifically change any settings. The convenience of such a memory is obvious: it allows, if necessary, to return to previous results and clarify a particular value without repeating the measurement. It is only necessary to bear in mind two points. Firstly, the number of memory cells can be different - as a rule, it is in the range from 20 to 100 and is indicated here, right under the words "memory of the last measurements." Secondly, when these cells overflow, the newest results are automatically overwritten in place of the oldest ones; and such a function as protecting individual cells from overwriting is usually not found in laser rangefinders (although exceptions are possible - this point should be clarified in the documentation for a particular device).

- Calculator. A traditional calculator that allows you to perform various calculations at the request of the user. These can be both operations with data obtained during measurements, and operations with numbers entered manually.

— Horizontal mode Smart. "Smart" mode, which allows you to measure and calculate a whole range of dimensions and angles, literally on the spot. A typical example of the implementation of Smart looks like this: a rangefinder from the same point measures two distances to a wall or other similar object - one is the smallest (along the perpendicular), and the second to a certain point “nearby”. After that, based on the received data, the device calculates the angle of rotation and the distance between the points. Other, more specific functions are also possible.

— Measurement of inclined objects. Various additional functions related to the measurement of inclined objects (in addition to determining the angle of inclination described above). The specific set of such capabilities may vary; they should be specified separately.

We also note that in modern rangefinders there may be other possibilities, in addition to tech listed above.