Rockwell Automation GMLC Reference Manual - Manual (Page 689)

Publication GMLC-5.2 - November 1999
652 Mathematical Functions
The base of the Log function is e, is an irrational number, which to 15
decimal places, is equal to 2.71828 18284 59045.
The argument can be any floating point value or expression, but must be
greater than zero. A negative or zero argument gives a value of 0 for the
Log function.
For example, the following expression is evaluated as 0.693xx since ln 2 =
0.6931.
Log(2)
Note that the Log function is the inverse of the Exponent function. In
other words, for all values of x:
Log(Exponent(x)) = x
To find the common logarithm (base 10 logarithm or log
10
) of an
argument, divide the Log function by ln 10. For example, the following
expression is evaluated as 0.3010xx since log
10
2 = 0.3010.
Log(2) / Log(10)
Argument
+1
+2
–1
–2
1 2 3 4
e