# Curve\_20XY\_Real\_Real
## `Curve_20XY_Real_Real` (FB)
FUNCTION\_BLOCK Curve\_20XY\_Real\_Real
### Short description
> Input of 20 pairs of values (support points each with an X and Y value)\
> Boundary conditions:
>
> 1. The X values must be continuously either strictly increasing or strictly decreasing
> 2. Each X value may only be present once
> 3. Two adjacent support points are each connected by a straight line\
> \
> Typical application: Calculation of a heat pump's performance depending on the outdoor temperature
### Representation
### Interfaces
#### Inputs
| Name | Data type | Value range | Initial value | Function |
| ---------------------- | --------- | ----------- | ------------- | ----------------------------------- |
|
rInputValue
| REAL | | 0 | Current value of the input variable |
#### Outputs
| Name | Data type | Value range | Initial value | Function |
| ------------------------ | ------------------------------- | ----------- | ----------------------------------------- | ----------------------------------------------- |
|
rOutputValue
| REAL | | 0.0 | Current value of the output variable |
|
eOrderXValues
| eCurve\_20XY\_Real\_Real\_Order | | eCurve\_20XY\_Real\_Real\_Order.Invalid | Order of the X values (increasing / decreasing) |
|
eError
| eCurve\_20XY\_Real\_Real\_Error | | eCurve\_20XY\_Real\_Real\_Error.No\_Error | Cause of error |
|
xError
| BOOL | | FALSE | Error state (TRUE = error) |
#### Setpoints / parameters
| Name | Data type | Value range | Initial value | Function |
| ------------------------------ | --------- | ----------- | ------------- | -------------------------------------------------------- |
|
rOutputValue\_Subst
| REAL | | -1000 | Substitute value of the output variable in case of error |
|
rOutputValue\_Min
| REAL | | 0 | Absolute minimum value of the output variable |
|
rOutputValue\_Max
| REAL | | 100 | Absolute maximum value of the output variable |
|
rSP1\_X
| REAL | | 1 | Support point 1 - X value |
|
rSP1\_Y
| REAL | | 2 | Support point 1 - Y value |
|
rSP2\_X
| REAL | | 2 | Support point 2 - X value |
|
rSP2\_Y
| REAL | | 4 | Support point 2 - Y value |
|
rSP3\_X
| REAL | | 3 | Support point 3 - X value |
|
rSP3\_Y
| REAL | | 6 | Support point 3 - Y value |
|
rSP4\_X
| REAL | | 4 | Support point 4 - X value |
|
rSP4\_Y
| REAL | | 8 | Support point 4 - Y value |
|
rSP5\_X
| REAL | | 5 | Support point 5 - X value |
|
rSP5\_Y
| REAL | | 10 | Support point 5 - Y value |
|
rSP6\_X
| REAL | | 6 | Support point 6 - X value |
|
rSP6\_Y
| REAL | | 12 | Support point 6 - Y value |
|
rSP7\_X
| REAL | | 7 | Support point 7 - X value |
|
rSP7\_Y
| REAL | | 14 | Support point 7 - Y value |
|
rSP8\_X
| REAL | | 8 | Support point 8 - X value |
|
rSP8\_Y
| REAL | | 16 | Support point 8 - Y value |
|
rSP9\_X
| REAL | | 9 | Support point 9 - X value |
|
rSP9\_Y
| REAL | | 18 | Support point 9 - Y value |
|
rSP10\_X
| REAL | | 10 | Support point 10 - X value |
|
rSP10\_Y
| REAL | | 20 | Support point 10 - Y value |
|
rSP11\_X
| REAL | | 11 | Support point 11 - X value |
|
rSP11\_Y
| REAL | | 22 | Support point 11 - Y value |
|
rSP12\_X
| REAL | | 12 | Support point 12 - X value |
|
rSP12\_Y
| REAL | | 24 | Support point 12 - Y value |
|
rSP13\_X
| REAL | | 13 | Support point 13 - X value |
|
rSP13\_Y
| REAL | | 26 | Support point 13 - Y value |
|
rSP14\_X
| REAL | | 14 | Support point 14 - X value |
|
rSP14\_Y
| REAL | | 28 | Support point 14 - Y value |
|
rSP15\_X
| REAL | | 15 | Support point 15 - X value |
|
rSP15\_Y
| REAL | | 30 | Support point 15 - Y value |
|
rSP16\_X
| REAL | | 16 | Support point 16 - X value |
|
rSP16\_Y
| REAL | | 32 | Support point 16 - Y value |
|
rSP17\_X
| REAL | | 17 | Support point 17 - X value |
|
rSP17\_Y
| REAL | | 34 | Support point 17 - Y value |
|
rSP18\_X
| REAL | | 18 | Support point 18 - X value |
|
rSP18\_Y
| REAL | | 36 | Support point 18 - Y value |
|
rSP19\_X
| REAL | | 19 | Support point 19 - X value |
|
rSP19\_Y
| REAL | | 38 | Support point 19 - Y value |
|
rSP20\_X
| REAL | | 20 | Support point 20 - X value |
|
rSP20\_Y
| REAL | | 40 | Support point 20 - Y value |
### Function description
\
The output variable **rOutputValue** is cyclically calculated based on the input variable **rInputValue** and the characteristic curve defined by the 20 support points, provided no error is present (xError = FALSE).
It is limited by the adjustable absolute minimum (rOutputValue\_Min) and maximum values (rOutputValue\_Max).\
In the event of an error (xError = TRUE), the fixed substitute value for the output variable 'rOutputValue' **rOutputValue\_Subst** is output.\
\
The X values of the 20 support points must meet the following boundary conditions:\
\
1\) The X values must be continuously either strictly increasing or strictly decreasing\
2\) Each X value may only be present once\
3\) Two adjacent support points are each connected by a straight line\
\
The updating of the characteristic curve takes place once immediately after initialization or once after each change of the support points.\
\
In the event of an error (identical X values, X values not strictly increasing / decreasing) a corresponding cause of error is shown at the output **eError** is displayed.\
At the same time, the fixed substitute value for the output variable 'rOutputValue' **rOutputValue\_Subst** is output.\
The output **xError** is active (= TRUE) if at the output **eError** an error is signaled.
### Representation of an example characteristic curve
### CODESYS
InOut:
| Scope | Name | Type | Initial |
| ----------- | -------------------- | ------------------------------- | ----------------------------------------- |
| Input | `rInputValue` | `REAL` | 0 |
| Output | `rOutputValue` | `REAL` | 0 |
| Output | `eOrderXValues` | eCurve\_20XY\_Real\_Real\_Order | eCurve\_20XY\_Real\_Real\_Order.Invalid |
| Output | `eError` | eCurve\_20XY\_Real\_Real\_Error | eCurve\_20XY\_Real\_Real\_Error.No\_Error |
| Output | `xError` | `BOOL` | FALSE |
| Input Const | `rSP20_Y` | `REAL` | 40 |
| Input Const | `rSP20_X` | `REAL` | 20.0 |
| Input Const | `rSP19_Y` | `REAL` | 38.0 |
| Input Const | `rSP19_X` | `REAL` | 19.0 |
| Input Const | `rSP18_Y` | `REAL` | 36.0 |
| Input Const | `rSP18_X` | `REAL` | 18.0 |
| Input Const | `rSP17_Y` | `REAL` | 34.0 |
| Input Const | `rSP17_X` | `REAL` | 17.0 |
| Input Const | `rSP16_Y` | `REAL` | 32.0 |
| Input Const | `rSP16_X` | `REAL` | 16.0 |
| Input Const | `rSP15_Y` | `REAL` | 30.0 |
| Input Const | `rSP15_X` | `REAL` | 15.0 |
| Input Const | `rSP14_Y` | `REAL` | 28.0 |
| Input Const | `rSP14_X` | `REAL` | 14.0 |
| Input Const | `rSP13_Y` | `REAL` | 26.0 |
| Input Const | `rSP13_X` | `REAL` | 13.0 |
| Input Const | `rSP12_Y` | `REAL` | 24.0 |
| Input Const | `rSP12_X` | `REAL` | 12.0 |
| Input Const | `rSP11_Y` | `REAL` | 22.0 |
| Input Const | `rSP11_X` | `REAL` | 11.0 |
| Input Const | `rSP10_Y` | `REAL` | 20.0 |
| Input Const | `rSP10_X` | `REAL` | 10.0 |
| Input Const | `rSP9_Y` | `REAL` | 18.0 |
| Input Const | `rSP9_X` | `REAL` | 9.0 |
| Input Const | `rSP8_Y` | `REAL` | 16.0 |
| Input Const | `rSP8_X` | `REAL` | 8.0 |
| Input Const | `rSP7_Y` | `REAL` | 14.0 |
| Input Const | `rSP7_X` | `REAL` | 7.0 |
| Input Const | `rSP6_Y` | `REAL` | 12.0 |
| Input Const | `rSP6_X` | `REAL` | 6.0 |
| Input Const | `rSP5_Y` | `REAL` | 10.0 |
| Input Const | `rSP5_X` | `REAL` | 5.0 |
| Input Const | `rSP4_Y` | `REAL` | 8.0 |
| Input Const | `rSP4_X` | `REAL` | 4.0 |
| Input Const | `rSP3_Y` | `REAL` | 6.0 |
| Input Const | `rSP3_X` | `REAL` | 3.0 |
| Input Const | `rSP2_Y` | `REAL` | 4.0 |
| Input Const | `rSP2_X` | `REAL` | 2.0 |
| Input Const | `rSP1_Y` | `REAL` | 2.0 |
| Input Const | `rSP1_X` | `REAL` | 1.0 |
| Input Const | `rOutputValue_Max` | `REAL` | 100.0 |
| Input Const | `rOutputValue_Min` | `REAL` | 0.0 |
| Input Const | `rOutputValue_Subst` | `REAL` | -1000.0 |
---
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