# Virtual Variables

Virtual Variables are used to create new calculated variables that are a mathematical function of one or more sensor readings. Virtual Variables are useful to re-scale sensors (like from °C to °F) as well as to calculate results that were not calculated in the data logger. It is easy to create an equation using sensor readings from a single or multiple data loggers. When creating a set of similar virtual variables you may speed up the work by using the Duplicate function.

Virtual Variables are a handy tool to calibrate or scale sensor readings in a post-processing action which may simplify data logger programming or provide results that were otherwise lost.  As an example about scaling a vibrating wire sensors returning digits may be scaled using the Virtual Variables feature of VDV.

### The available operators of Virtual Variable are:

+: Addition operator
-: Minus operator
*: Multiplication operator
/: Division operator
(): Parenthesis
^: Returns the value of X raised to the power of Y (X^Y).
%: Modulo operation. Returns the remainder of N divided by M.
abs: Return the absolute value
round: Round the argument. It is possible to use Decimal Places Round round(X,D). Only available in Advanced Equation tab.
floor: Return the largest integer value not greater than the argument
ceil: Return the smallest integer value not less than the argument
cos: Return the cosine
sin: Return the sine of the argument
tan: Return the tangent of the argument
acos: Return the arc cosine. Result is in Radians.
asin: Return the arc sine. Result is in Radians.
atan: Return the arc tangent. Result is in Radians.
cot: Return the cotangent
rad: Return argument converted to radians
deg: Convert radians to degrees
ln: Return the natural logarithm of the argument
log2: Return the base-2 logarithm of the argument
log10: Return the base-10 logarithm of the argument
exp: Returns the value of e (the base of natural logarithms) raised to the power of X.
sqrt: Return the square root of the argument