Neraca Digital/Elektronik

Function

In everyday life, often interpreted as a heavy mass, but in a review of physics both these quantities are different. Gravitational mass is unaffected, while the weight is affected by gravity. Function of electric and non electric balance in general is a mass of gauges. The usefulness of this balance depends on the scale of the balance sheet eg / electric scales in supermarkets in the laboratory with a sensitivity and scale of its balance sheet is much different.

The measurement process

In general the balance meninbang with electronic / digital are:

Make sure that the scales are lit.

Make sure the scale shows the number "zero" (if it is not necessary in the correction).

Letakakan object whose mass is to be measured on the disc where the object.

Read the scale indicated on the digital display unit according to the scale of these scales.

For high sensitivity measurements have to wait 30 minutes, because it can only work on a specified temperature limit.

Calibration

Controlling Scales / Balance Sheet

Scales / Balance is controlled by using weights that are attached or with two external weights, ie 10 gr and 100 gr. Scales / Balance electronics, have to wait 30 minutes to adjust the temperature. If a balance is very sensitive, can only work at specified temperature limit. Scales should be protected from movement (wind) before considering the number "zero" must be checked and if necessary do a correction. Weight deviations are recorded on the sheet / card control, which are listed on the sheet the number of times the scales must be checked. If the scales can not be used at all the scales must be repaired by an agent (supplier).

Cleanliness of the scales

Cleanliness of the scales should be checked after each use, parts and weighing should be cleaned using a brush, soft cloth or paper (tissue) and clean the whole weight scales must be turned off, then the dish (pan) scales can be removed and all the scales can be cleaned using cleaning like a soft detergent, mix water and ethanol / alcohol. After cleaning the scales are turned on and after heating, check back with the weights.

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Anemometer

Function Anemometer

Observation of the elements of weather and climate requires meteorological tools that are sensitive, robust, simple and precise. Judging from the way the readings, meteorological equipment consists of two types, namely:

Recording is a tool that can record data continuously, since the installation until the turn of the next tool. Example: barograf and anemograf.

Non recording tool that is used when data must be read at certain times to obtain the data. Example: barometer, and anemometer ermometer.

Anemometer is a device used to measure wind speed and direction. Meteorological unit of wind speed is Knots (Beaufort Scale). While the meteorological unit of wind direction is 0o - 360o and direction of the wind. Anemometer should be placed in open areas.

At the time of the wind, baling-baling/mangkok contained on the anemometer will be moving in the direction of the wind. The greater the wind speed blowing bowls are, the faster the speed of rotation of the disc bowls. Of the number of revolutions in one second it can be seen the wind speed. Anemometer at the counter there is a tool that will calculate the wind speed. The results obtained enumerator recorded instrument, then matched with Beaufort.c Scale Figure Anemometer is:

Type Anemometer

Anemometer itself there are two general types. Types are as follows:

a. Anemometer with three or four bowls

The sensor consists of three or four fruit bowl mounted on a radius centered on a vertical axis or all of the bowl is mounted on a vertical axis. The whole bowl is facing a circumferential direction so that when the wind blows the rotor rotates in the direction fixed. Rotational speed of the rotor depends on wind speed. Through a mechanical system of gears, rotor rotation rate of accumulation systems regulate the distance the wind pointer. Anemometer type "cup counter" can only measure the average wind speed over a period of observation. With this tool, the addition of value that can be read from one observation to the next observation, stating the accumulated mileage of wind during the time of the second observation, so that the wind speed is equal to the accumulated distance traveled divided by time interval of the observations.

b. Thermal Anemometer

This anemometer is a sensor used to measure the velocity of a fluid (air) shortly. The workings of this sensor is based on the amount of the convective heat loss from the sensor to the environment around the sensor. The amount of heat transferred from the sensor is directly related to the fluid velocity passing through the sensor. If only the fluid velocity is changed, then the heat loss can be interpreted as the fluid velocity. Anemometer work follows the principle of pitot tube, which is calculated from the static pressure and velocity pressure.

Anemometer Measurement Process

The following example of a simple calculation of the wind velocity measured by three cup anemometer. Long circular arrangement of bowls is 3 m, and the composition at a time rotating it 20 times in 10 seconds, then the wind speed can be calculated: [(20x3) / 10 m = 6 m / s]

To facilitate the counting rotation of the disc then one cup anemometer was given another color.

Because of differences with respect to wind speed from a variety of different heights, then the installation of the anemometer height is usually adapted to the purpose or usefulness. For fields with a height sensor mounted agroklimatologi (bowl) 2 meters above ground level. To collect supporting data for the Class A pan evaporation measurements, anemometer mounted as high as 0.5 m. In general, the airfield installation height of 10 m. Listed open area at stake that is strong enough. For the purposes of navigation tools should be installed at a distance of 10 x height barrier factors such as a building or tree. Most of the Anemometer is generally not able to record wind speeds below 1-2 miles / hour because there is friction factor of what the early rounds.

Anemometer calibration process

Anemometer calibration process is done periodically in order perfomansi and recording the results remained stable and good. The following sequence on the anemometer calibration process.

For wind direction calibration, the method can yield Following an accuracy of ± 5 ° or better if carefully done. Begin by connecting the instrument to a signal conditioning circuit the which indicates wind direction value. This may be an indicator of the which displays wind direction values ​​in angular degrees or simply a voltmeter monitoring the output. Hold or mount the instrument so the vane center of rotation is over the center of a sheet of paper the which has 30 ° or 45 ° crossmarkings. Position the mounting theinstrument so crossarm is oriented north-south with the vane on the north and the anemometer on the south. With the counterweight pointing directly at the anemometer the wind direction signal should correspond to 180 ° or due south. Looking from above, visually align the vane with each of the crossmarkings and Observe the indicator display. It should correspond to vane position within 5 °. If not, it may be Necessary to adjust the relative position of the vane skirt and shaft. See step 3 in the MAINTENANCE section under potentiometer replacement.

It is Important to note That while the sensor mechanically rotates through 360 °, the full scale wind direction signal from the signal conditioning Occurs at 352 °. For example, in a circuit where 0 to 1:00 VDC represents 0 ° to 360 °, the output must be adjusted for 0978 VDC when the instrument is at 352 ° full scale. (352 ° / 360 ° 1:00 X volts = 0978 volts).

Wind speed calibration is determined by the cup wheel turning factor and the output characteristics of the transducer. Calibration Formulas showing cup wheel rpm and output frequency vs. wind speed are included below.

Calibration Formulas for Model 03 102 Wind Sentry Anemometer

WIND SPEED RPM vs CUP WHEEL

m / s = (0.01250 x rpm) + 0.2

knots = (0.02427 x rpm) + 0.4

mph = (rpm x 0.02795) + 0.4

km / hr = (0.04499 x rpm) + 0.7

WIND SPEED vs OUTPUT FREQUENCY - Hz

m / s = (0.7500 x Hz) + 0.2

knots = (1.4562 x Hz) + 0.4

mph = (1.6770 x Hz) + 0.4

km / hr = (2.6994 x Hz) + 0.7

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Termometer Digital

Digital Thermometer Functions
A thermometer is one measure that serves to determine the temperature of the object (the object / body).
The working principle of Digital Thermometers
Digital thermometer, usually using a thermocouple as a sensor for reading the resistance value changes. Simply put the thermocouple in the form of two wires of different metals that end, only the tip alone, together (welded). The point of this convergence is called hot junction. The principle works utilizing the characteristics of the relationship between voltage (volts) with temperature. Any type of metal, at a given temperature have certain voltage as well. At the same temperature, the metal A has a different voltage to the metal B, there was a voltage difference (small, millivolts) which can be detected. So the input temperature of the environment after the thermocouple is detected as a difference in voltage (volts). This voltage is then converted back to the current value through pengkomparasian with reference values ​​and the offset value in the comparator, its function is to translate each unit into the unit volt ampere then used as a temperature scale that is displayed through the display / monitor in the form of seven segments that show the temperature detected by the thermocouple .

These thermocouples vary, depending on the type of metal used. Type of metal will determine the temperature range that can be measured (thermocouple temperature (low temperature) differs from the thermocouple to measure the temperature of the furnace fuel (high temperature)), as well as sensitivity.
In detail the working principle of a digital thermometer can be explained as follows:
Sensory form of PTC or NTC with a high level of sensitivity will change the value of the prisoner if there is a temperature which prubahan about it.
This resistance value changes linearly with changes in flow, so the value of this current can be converted into the form view display
Before being converted, the value of this current in comparison with the reference value and the offset value in the comparator, its function is to translate each unit volt ampere into the unit which will be converted to display.
Digital thermometer readings Measurement

Reading of thermometer measurements are performed directly from the display with respect to the existing line segment.
Digital Thermometer Calibration

Regular calibration using manual or automatic calibration, manual calibration temperature sensor which is subject to the actual heater temperature from 0 degrees to ofsetnya setting. Automatic calibration consists of heating temperature and the gain in circuit checker for komparatornya
Composer Material Digital Thermometer

Penyususn digital thermometer has a most important part. Constituent materials are as follows:

Sensor PTC / NTC
Comparator (OP-amps and the like)
Analog to Digital converter
Decoder display (eg TTL IC 7447)
Display (7 segment, LCD, monitor)

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Termometer Air Raksa

Mercury thermometer function
The thermometer is a device for measuring temperature. Thermometer analog thermometer can also be called as a manual, because the way the reading

still manual. The use of mercury as the main ingredient thermometer because the mercury expansion coefficient relatively constant so that changes in volume due to increase or decrease in temperature is almost always the same. But there are also some families thermometer contains alcohol with the addition of red dye. Thermometer is safer and easier to read.]

A special type of mercury thermometers, called a maximum thermometer, working with the valve on the neck of the tube near the bulb. When the temperature rises, the mercury is pushed upwards by the force through the expansion valve. When the temperature drops of mercury retained in the valve and can not return to the bulb to keep the mercury in the tube. The reader can then read the maximum temperature for a predetermined time. To restore its function, the thermometer should be swung hard. This thermometer medical thermometer-like design.

Mercury will freeze at a temperature of -38.83 ° C (-37.89 ° F) and can only be used at temperatures above it. Mercury, unlike water, does not expand when frozen so it does not break the glass tube, making it difficult to observe when it freezes. If the thermometer contains nitrogen, the gas may flow down into the column and trapped there when the temperature rises. If this happens the thermometer can not be used to return to the initial conditions. To avoid this, the mercury thermometer should be put in a warm place at temperatures below -37 ° C (-34.6 ° F). In the area where the maximum temperature is expected to rise above - 38.83 ° C (-37.89 ° F) thermometer that uses a mixture of mercury and thallium may be used. This thermometer has a freezing point of -61.1 ° C (-78 ° F).

Measurement of Mercury Thermometers

Generally use a mercury thermometer scale Celsius temperature and Fahrenhait. Celsius used two important points on the scale: the temperature when the ice melts and the water evaporation temperature. Ice melt at the same calibration mark on the thermometer in the steam of boiling water. When the thermometer out of water vapor, the height of the mercury down slowly. This relates to the rate of cooling (and the expansion of the glass tube). So pegukuran celsius temperature using the temperature of melting and freezing temperatures are not.

Celsius is the boiling point of 0 ° C (212 ° F) and freezing at 100 ° C (32 ° F). But other researchers, Frenchman Jean Pierre Cristin proposed version of the reverse-Celsius scale the freezing point at 0 ° C (32 ° F) and boiling at 100 ° C (212 ° F). He named it Centrigade.

The workings of Mercury Thermometers

This device consists of a capillary tube using a glass material containing mercury at the lower end. For measurement purposes, the pipe is made in such a way that the vacuum. If the temperature increases, the mercury will expand up to the top of the pipe and provide clues about the temperature gauge in accordance with a predetermined scale. The general way of working is as follows;

Prior to the change in temperature, the volume of mercury is in the initial conditions.
Temperature changes in the environment around the mercury thermometer responded with volume changes.
The volume of mercury will expand if the temperature increases and will shrink when the temperature decreases.
The scale of the thermometer will indicate the temperature corresponding state of the environment.

Calibration Mercury Thermometers

Calibration is the process of verifying that an accuracy of measuring instruments in accordance with the design. Calibration is usually done by comparing a standard that is connected with national and international standards and certified reference materials.

Thermometer calibration process include:

Place the thermometer in the water cylinder is being melted and check points around the thermometer when the liquid water entirely. This point is the freezing point of water.
In the same way, mark the point when the thermometer throughout the entire boiling water when heated.
For the length of the above two points into one hundred equal parts.

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