Square Root Extraction (SQRTX)
Within a specified range, calculates the square root of a REAL value
as a percentage:
OUT = sqrt( ((Min(Max(PV, IPmin), IPmax) - IPmin) / (IPmax - IPmin))
) * 100
Parameter values for the SQRTX function:
Parameter | Data Type | Description | ||
|---|---|---|---|---|
PV | REAL | Process variable, scaled to a value of 0..1, according to IPmax and IPmin. This value must be a positive REAL value. | ||
IPmax | REAL | Maximum positive REAL value of the process
variable (PV). Infinity or Not a Number (NaN) values are not supported by this
input. | ||
IPmin | REAL | Minimum positive REAL value of the process
variable (PV). Infinity or Not a Number (NaN) values are not supported by this
input. | ||
OUT | REAL | Square root of the input value calculated as a
percentage. When the PV value is greater than IPmax, the function returns a value of
100.0. When the PV value is less than IPmin, the function returns a value of
0.0. | ||
TIP:
Loss of precision may occur when using this
function.
When IPmax < IPmin, the function assumes that the values are reversed
and swaps them. The
ERRSTAT
Reversed error counter increments each time the function
has to swap the parameters.When IPmax = IPmin, the function returns a value of zero
and the
ERRSTAT
Zero Divide error counter increments.When PV is Not a Number
(NaN) value, OUT is set to zero and the
ERRSTAT
Param error counter
increments.When an overflow or underflow condition occurs during execution of the
function, the function returns zero and increments the corresponding
ERRSTAT
Overflow
or Underflow error counter.Function Block Diagram
Example
Structured Text Example
Result
:= SCALE(PV, 2.0, 0.2);
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