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LN |
  
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LN |
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Block that calculates the natural logarithm of the Value value, storing the result in Result.
Ladder Representation
Block Structure
Variable Type |
Name |
Data Type |
Description |
VAR_INPUT |
EN |
BOOL |
Block enabling |
Value |
REAL |
Reference variable for the operation |
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VAR_OUTPUT |
Done |
BOOL |
End of operation |
Result |
REAL |
Variable that stores the result of the operation |
Operation
When this block has a TRUE value in EN, it sends to the Result output the natural logarithm of the Value variable. If no errors, the Done variable is set. If there is any error in the operation, Done is not set, staying in FALSE status, while Result remains with its value unchanged.
When EN has FALSE value, Result remains unchanged and Done remains in FALSE.
Block Flowchart
Example in Ladder
The above example calculates the natural logarithm of the VALUE variable, storing the final result in RESULT. The block ends with success and Done output is activated.
The above example calculates the natural logarithm of the VALUE variable, storing the final result in RESULT. The block generates a runtime error, since VALUE has value zero, and Done output is disabled.
Example in ST
The example below displays the instructions for applying the example above in the ST language.
VAR VALUE : REAL := 50.0; RESULT : REAL; END_VAR
RESULT := FB_LN(EN:=DI1, Value:=VALUE, Done=>DO1);
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