# 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