Humidity logger units can be found where delicate machinery is located, such as in computer systems. Some areas, such as computer banks, also require humidity to be strictly controlled. Without the humidity logger, too much humidity can lead to damage within this sensitive equipment.
A humidity logger is generally small enough to fit in a person’s hand. Most humidity logger units mount easily onto a wall. Due to their small size, they can also be carried in a pocket to be placed anywhere they are needed. There are thirteen different logging intervals to select from on the average humidity logger unit. A humidity logger can be set from 1 second to 60 minutes, and delayed start times can be preprogrammed through a computer using the provided software. Today’s humidity logger units use an average measurement interval of 30 minutes and can provide up to four months of power with just AA batteries. The data saved within the unit is retained in memory when the unit is powered off.
Each humidity logger unit has easy controls that allow the unit to be programmed to display the correct date and time. Controls also include selecting temperature units, starting and stopping logging, and selecting logging intervals. An easy to read display offers a bar chart on the front-panel and shows the amount of memory used.
Most new humidity logger units have a large LCD display, which makes the compact logger easier to set-up and more convenient to use. Another type of humidity logger is the “blind" logger, which requires a computer to read values or set-up a log session. This makes it more difficult to measure temperature and humidity when away from a computer, such as when on a job site.
Most humidity logger units are self-sufficient systems that measure temperature and/or humidity and record the result in a protected memory section. According to one leading company, the recording rate is user-defined. A total of 8,192 8-bit readings or 4,096 16-bit readings, taken at equidistant intervals ranging from 1 second to 273 hours, can be stored. In addition to this, there are 512 bytes of SRAM for storing application-specific information and 64 bytes for calibration data.
Information for a specific job to collect data can be programmed in the humidity logger to begin immediately or to wait until later. These units can also be set up to begin measuring after a temperature alarm has been sounded. If security is an issue, the humidity logger unit can be password protected to protect the memory and control functions. This is important for those who do not want anyone to change the programming that has already been set up within the unit.