Log Base 10 (LOG)
The LOG instruction takes the log base 10 of the Source and stores the result in the Destination. The Source must be greater than zero or a minor fault will occur.
Available Languages
Ladder Diagram
Operands
IMPORTANT:
Unexpected operation may occur if:
- Output tag operands are overwritten.
- Members of a structure operand are overwritten.
- Except when specified, structure operands are shared by multiple instructions.
There are data conversion rules for mixing numeric data types within an instruction. See Data conversions.
Ladder Diagram
Operand | Data Type | Format | Description |
|---|---|---|---|
Source | SINT INT DINT LINT USINT UINT UDINT ULINT REAL LREAL | Immediate tag | Value for which the instruction finds the log. |
Destination | SINT INT DINT LINT USINT UINT UDINT ULINT REAL LREAL | tag | Tag to store the result of the instruction. |
Affects Math Status Flags
Yes
Major/Minor Faults
None specific to this instruction. See Index through arrays for array-indexing faults.
Execution
Ladder Diagram
Condition/State | Action Taken |
|---|---|
Prescan | N/A |
Rung-condition-in is false | Set Rung-condition-out to Rung-condition-in. |
Rung-condition-in is true | Set Rung-condition-out to Rung-condition-in. Dest = value of log base 10 of the Source. |
Postscan | N/A. |
Examples
Ladder Diagram
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