Honeywell Frequently Asked Questions
TEMPERATURE
WHAT IS THE TEMPERATURE?
The temperature is a measure of how cold or hot the place is.
Our products use thermo resistor or thermistor for temperature measurements that changes its resistance with changes in the temperature. A microcontroller measures the resistance and converts it to temperature digits to be displayed.
WHAT IS THE TEMPERATURE COMPENSATION?
The temperature compensation is the ability to correct any errors in the system due to changes in ambient temperature.
Temperature compensation is the process of making some characteristic of a circuit or device relatively independent of changes in ambient temperature .
WHAT IS THE DIFFERENCE BETWEEN THE ACCURACY AND RESOLUTION?
Accuracy is the measurement device's degree of absolute correctness, whereas resolution is the smallest number that can be displayed or recorded by the measurement device.
WHAT DOES HEAT INDEX MEAN?
Heat Index uses temperature and relative humidity to determine how hot the air actually " feels". When humidity is low, the apparent temperature will be lower than the air temperature, since perspiration evaporates rapidly to cool the body. However, when humidity is high (i.e., the air is saturated with water vapor) the apparent temperature "feels" higher than the actual air temperature, because perspiration evaporates more slowly.
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Temperature (ºC) versus Relative Humidity (%) |
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|
ºC |
90% |
80% |
70% |
60% |
50% |
40% |
|
26.5 |
29.5 |
29 |
28 |
27 |
26.5 |
26 |
|
29.5 |
38.5 |
35.5 |
33 |
32 |
30 |
29 |
|
32 |
49 |
45 |
41 |
37 |
34 |
32 |
|
35 |
|
56 |
50 |
45 |
41 |
36.5 |
|
38 |
|
|
61 |
54 |
48 |
42 |
|
41 |
|
|
|
64 |
56 |
49 |
|
43 |
|
|
|
|
|
57 |
|
|
|
|
|
|
|
|
|
HI |
|
Possible Heat Disorder: |
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|
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|
26.5ºC - 32ºC |
Fatigue possible with prolonged exposure and physical activity. |
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32ºC - 41ºC |
Sunstroke, heat cramps and heat exhaustion possible. |
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41ºC - 54.5ºC |
Sunstroke, heat cramps and heat exhaustion likely, and heat |
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54.5ºC or greater |
Heat stoke highly likely with continued exposure. |
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HUMIDITY
WHAT IS HUMIDITY?
Absolute humidity is the weather element which indicates the actual amount of water vapor in a unit volume of air.
Relative humidity is a weather element which indicates the ratio between absolute humidity and humidity capacity at a given temperature, usually expressed as a percentage.
WHAT IS HYGROMETER?
The hygrometer is an instrument used to measure humidity. There are several different kinds of hygrometers, including sling psychrometers and hair hygrometers.
WHAT IS DEW POINT?
The temperature the air would have to be cooled to in order for it to become saturated, or full, of water vapor. If the dew point is 55, then the air would become "full" of water vapor if it was cooled to 55 degrees.
PRESSURE
WHAT IS PRESSURE?
The pressure is a force applied uniformly over a surface, measured as force per unit of area, or pressure is a measure of force per unit.
The air's pressure is caused by the weight of the air pressing down on the Earth, the ocean and on the air below. Earth's gravity causes the downward force that we know as "weight." Since the pressure depends on the amount of air above the point where you're measuring the pressure, the pressure falls as you go higher.
WHAT IS THE BAROMETRIC PRESSURE?
Air pressure is also called barometric pressure because instruments called barometers are used to measure it.
WHAT IS THE ATMOSPHERIC PRESSURE?
Atmospheric pressure is the pressure caused by weight of the air above any area in Earth's atmosphere.
WHAT IS THE STANDARD ATMOSPHERIC PRESSURE?
Standard atmospheric pressure or standard atmosphere (1 Atm) is defined as 101.325 KPa, or 29.92 inches of Mercury, or 760 mm of Mercury.
WHAT IS MERCURY?
Mercury, also called quicksilver, is a chemical element in a periodical table, has symbol Hg and atomic number 80. It is a heavy transition metal. The mercury is only the one of two elements that is liquid at room temperature (the other one is bromine Br)
WHAT IS ALTITUDE?
The altitude is a height above the earth's surface
HOW CAN I FIND OUT MY LOCAL ALTITUDE?
There are several places where you can find out your location's altitude, such as an airport, many local government facilities, or often on city limit signs.
WILL ALTITUDE AFFECT THE PERFORMANCE OF THE WEATHER STATION?
The only device affected by altitude is a barometric pressure sensor. Higher altitude, lower the barometric pressure is.
HOW TO ADJUST THE SEA LEVEL ON MY WEATHER STATION?
You can enter your local altitude either in feet or meters, if your weather station has a SEA LEVELADJUSTMENT feature. Please refer to your product's User Manual for that.
WHAT IS THE SEA LEVEL PRESSURE?
The SEA LEVEL pressure is a pressure value obtained by the theoretical reduction of barometric pressure to sea level. Where the Earth's surface is above sea level, it is assumed that the atmosphere extends to sea level below the station and that the properties of that hypothetical atmosphere are related to conditions observed at the station.
WHAT IS MEAN SEA LEVEL PRESSURE?
Mean sea level pressure (MSLP or SLP) is the pressure at sea level or (when measured at a given height on land) the station pressure reduced to sea level by an appropriate altitude dependant formula. Ships at sea and low-lying weather stations must add (rather than subtract) a small correction to their barometric pressure readings (called "station pressure") to obtain the SLP.
This is the pressure normally given in weather reports on radio, television, and newspapers. When barometers in the home are set to match the local weather reports, they measure pressure reduced to sea level, not the actual local atmospheric pressure.
The reduction to sea level means that the normal range of fluctuations in pressure is the same for everyone. The pressures which are considered high pressure or low pressure do not depend on geographical location.
The altimeter setting in aviation, with two meanings either QNH or QFE (maybe one of these is MSLP above), is another atmospheric pressure reduced to sea level, but the method of making this reduction differs slightly.
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QNH barometric altimeter setting which will cause the altimeter to read altitude above mean sea level in the vicinity of an airfield.
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QFE barometric altimeter setting which will cause an altimeter to read height above a particular runway threshold.
Average sea-level pressure is 29.921 inches of mercury (inHg) or 1013.2 mbar. In aviation weather reports (METAR), QNH is transmitted around the world in millibars or hectopascals, except in the United States and Canada where it is reported in inches of mercury. (The United States also reports sea level pressure SLP, which is reduced to sea level by a different method, in the remarks section, not an internationally transmitted part of the code, in hectopascals or millibars. In Canada's public weather reports, sea level pressure is reported in kilopascals.) In the weather code, three digits are all that is needed, Decimal points and the one or two most significant digits are omitted: 1013.2 mbar or 101.32 kPa is transmitted as 132; 1000.0 mbar or 100.00 kPa is transmitted as 000; 998.7 mbar or 99.87 kPa is transmitted as 987; etc. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1032.0 mbar. The lowest measurable sea-level pressure is found at the centers of hurricanes (typhoons, etc).
WEATHER STATIONS
HOW IS THE WIRELESS WEATHER STATION POWERED?
The weather stations are battery powered - usually it takes 2 AA size alkaline batteries for the main unit (receiver) and 2 AA size alkaline (or lithium) batteries for the remote sensor (transmitter).
HOW LONG WILL THE BATTERIES LAST?
The average battery life in the wireless weather station is 12 months.
WHAT IS THE RANGE OF THE TRANSMISSION BETWEEN THE MAIN UNIT (RECEIVER) AND REMOTE SENSOR (TRANSMITTER)?
Most of the current wireless models have the operating range of 100 feet on the open area.
HOW OFTEN DOES THE WEATHER FORECAST UPDATE, AND WHAT PERIOD DOES IT COVER?
The weather forecast is updated every 12 hours and covers period from 12 to 24 hours ahead, starting from the first time when the unit has been powered up.
WHAT FREQUENCY MY WEATHER STATION OPERATES AT?
Your weather station operates on the 433MHz frequency.
WHAT IS A SENSOR?
The sensor is a device which detects a change in a physical stimulus and turns it into a signal which can be measured or recorded.