Square Root (SQRT)
The SQRT instruction and operator computes the square root of the Source and places the result in Dest.
If the Dest is not an LREAL/REAL, the instruction handles the fractional portion of the result as follows:
If the Source is: | The fractional portion of the result: | Example | ||
|---|---|---|---|---|
any elementary integer tag/value | Rounds | Source | DINT | 3 |
Dest | DINT | 2 | ||
any floating point tag/value | Rounds | Source | REAL | 3.0 |
Dest | DINT | 2 | ||
If the Source is negative, the instruction takes the absolute value of the Source before calculating the square root.
If the Source is a real data type and the Dest is an integer type, the instruction rounds the result. For example, if the real Source value is 3.0, the result is 1.732, and the Dest value becomes 2.
SQRT is used as an operator in ladder diagram expressions.
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 | Computes the square root of this value. |
Dest | SINT INT DINT LINT USINT UINT UDINT ULINT REAL LREAL | tag | Tag to store the result of the instruction. |
Affects Math Status Flags
See Math status flags.
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 = square root of Source. |
Postscan | N/A |
Examples
Ladder Diagram
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