Performs the logarithm on the input using the specified base.

The equation for the Log of x with a base of b is shown below:

Parameter

Description

Input Data*

Defines the time series data fed into the function. This can be a sensor ID or another function

Base

The base of the logarithm.

Log base 10 is considered the common algorithm, while the natural log uses a base of around 2.718.

*Input data is optional in most cases. If Info360 detects that the first input is time series data, it will be applied to the function. Otherwise, the current active sensor's data will be used, which is often the case in Reference Charts.

Example Usage as an Expression:

Log(10) - Outputs the logarithm of the current data stream with a base of 10. Log base 10 is used in log-scale graphs among other applications.

Log(Sensor('X'),2.718) - Outputs the natural log (approximately) on Sensor X.

Example Reference Chart:

The following example shows input data compared to the log of the input with a base of 10, 2, and 0.5.

When the input data equals 1, the log outputs equal 0.

When input is less than 1, the log generally becomes negative.

When the input is negative, the log becomes undefined.

Note that Log(0.5) = -log(2)


For information on setting up custom equations and syntax, please refer to Analytical Functions.