MOISTURE METER DESCRIPTION

Digital Moisture Meter for paper, wood and hardened material like plaster, concrete and mortar. Moisture meters are great to measure the moisture content in bulk solids, liquids and some gases. Some devices use infrared (IR), radio frequency (RF), or microwave techniques to evaporate water from a sample. Others determine moisture content by measuring a material’s conductance, resistance, or capacitance and calculating a corresponding moisture value. Variables measured include relative humidity, absolute humidity, specific humidity, and dew point. Relative humidity is a measure of the amount of water in the air compared with the amount of water the air can hold at a measured temperature. By contrast, absolute humidity is the mass of water vapor in a given volume of air. Specific humidity is the absolute humidity divided by the total mass of the given volume of air. Dew point is a measure of the temperature to which air needs to be cooled in order for saturation to occur. Moisture meters that measure pressure and temperature are commonly available. These specialized devices often include special circuitry or additional probes.

Selecting moisture meters requires an analysis of performance specifications and output options. Humidity range and dew point range are usually expressed as linear outputs. Humidity accuracy and dew point accuracy measure the closeness of a measured or computed value to its true value. Analog current outputs include variable levels such as 0 – 20 mA or 4 – 2 mA. Common analog voltage outputs are 0 – 10 V and ±5 V. Moisture meters with frequency or pulse outputs use amplitude modulation (AM), frequency modulation (FM) or pulse width modulation (PWM). With switch-type outputs, contacts are open or closed depending on the state of the variable being monitored.