Calculating The Common Logarithm - Mitsubishi MELSEC iQ-F FX5 series Programming Manual

16.4

Calculating the Common Logarithm

LOG(_E)
These functions output the operation result of the common logarithm (the logarithm whose base is 10) of an input value.
Ladder diagram
[Without EN/ENO]
s d
Setting data
■Descriptions, types, and data types
Argument
EN
s
ENO
d
Processing details
■Operation processing
• These functions calculate the logarithm whose base is "10" of the REAL type data input to (s), and output from (d).
• These functions are expressed as follows when the input value is "A" and the output operation result is "B".
B=log A
10
• A value input to (s) is the REAL type data value.
• Only a positive value can be set in (s). (The logarithm operation cannot be executed for a negative value).
• When the operation result is -0 or underflow occurs, the operation result is regarded as 0.
■Operation result
1.
Function without EN/ENO
The following table lists the operation results.
Operation result
No operation error occurred
An operation error occurred
2.
Function with EN/ENO
The following table lists the execution conditions and operation results.
Execution condition
EN
TRUE (Executes operation)
FALSE (Stops operation)
*1 When FALSE is output from ENO, data output from (d) is undefined. In that case, modify a program so that the data output from (d) is
not used.
16 SINGLE NUMBER VARIABLE FUNCTIONS
768
16.4 Calculating the Common Logarithm
[With EN/ENO]
EN ENO
s d
Description
Execution condition (TRUE: Execution, FALSE: Stop)
Input
Output condition (TRUE: Normal, FALSE: Abnormal)
Output
Operation result
ENO
TRUE (Operation error did not occur)
FALSE (Operation error occurred)
*1
FALSE
Structured text
[Without EN/ENO]
d:=LOG(s);
[With EN/ENO]
d:=LOG_E(EN,ENO,s);
Type
Input variable
Input variable
Output variable
Output variable
(d)
Operation output value
Indefinite value
(d)
Operation output value
*1
Indefinite value
Indefinite value
Data type
BOOL
REAL
BOOL
REAL