Calculating The Common Logarithm - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

26.4

Calculating the Common Logarithm

LOG(_E)
RnPCPU RnPCPU
RnCPU RnENCPU
(Process) (Redundant)
These functions output the common logarithm (logarithm with base 10) of an input value.
Ladder, FBD/LD
[Without EN/ENO]
s d
Setting data
■Description, type, data type
Argument Description
EN Execution condition (TRUE: Executed, FALSE: Not executed)
s (IN) Input
ENO Output status (TRUE: Normal, FALSE: Abnormal)
d Output
Processing details
■Operation processing
• These functions calculate the common logarithm of the REAL or LREAL data type value input to (s), and output the
operation result from (d).
• When the input value is defined as A and the output value is defined as B, the relationship of A and B will be as follows:
B=log A
10
• Input a REAL or LREAL data type value to (s).
• Input a positive value only. (Calculation cannot be performed with a negative value.)
• If the operation result is -0 or an underflow occurs, 0 will be output as the operation result.
■Operation result
1.
Function without EN/ENO
The operation processing is performed. The operation result is output from (d).
2.
Function with EN/ENO
The execution conditions and operation results will be as follows.
Execution condition
EN
TRUE (executed)
FALSE (not executed)
*1 If the value FALSE is output from ENO, the output data from (d) will be undefined. Create a program so that the undefined value will not
be used in operations.
RnSFCPU RnSFCPU
(Standard) (Safety)
[With EN/ENO]
EN ENO
s d
Operation result
ENO
TRUE
*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 result output value
Undefined value
26 SINGLE VARIABLE FUNCTIONS
26.4 Calculating the Common Logarithm
26
Data type
BOOL
ANY_REAL
BOOL
ANY_REAL
1897