Computer based gravimetric control for drying of wood

A small electrically heated experimental drying kiln was intended to be retrofitted with a computer based program for drying of wood using the theoretic basis of gravimetric method. An effort was made to use only standard equipment and computer in the regulatory system. The control program consists of 4 smaller parts. The main one is based on theoretical aspects of gravimetric method and Madison schedules, using the weight of a specimen in the drying kiln as the most important piece data. This data is calculated through the program, which provides the user with a permanent value of moisture content of the specimen. The temperature is also measured, and depending on the moisture content, it is raised or lowered by turning the heaters on and off. At the end of the drying period, when the value of 1 the current moisture content becomes equal to the intended final moisture content, the computer program automatically stops. The other parts of program are used only for analogical - digital (and vice versa) conversion of the recorded data. The applied method is assumed to be more precise than method based on electrical resistance of wood, while higher quality of dried wood and eliminating the implying a manual work are needed when the gravimetric method is normally used.