CHAR_LIN: Linear characteristic curve
The CHAR_LIN (FB460) block uses a linear characteristic curve (function) to calculate an output value for each input value.
This characteristic curve is defined by entering auxiliary points [X1, X2, Y1, Y2]. The interpolation between the auxiliary points is linear.
Functionality
The block calculates, for each input value [In], the output value [Out] from the parameterized characteristic curve [X1]/[Y1] and [X2]/[Y2].
Outside the function range defined by the auxiliary points [X1, X2, Y1, Y2], the output value corresponds to either the first or last auxiliary value.
Inputs
Pin | E | Description |
In | pa | Input |
X1 | pa | Auxiliary point X1 |
Y1 | pa | Auxiliary value Y1 |
X2 | pa | Auxiliary point X2 |
Y2 | pa | Auxiliary value Y2 |
Outputs
Pin | E | Description |
Out | a | Output |
Input values
Pin | Description | Data Type | Default value | E.g. Engineering unit or Text group | Min. | Max. |
In | Input | Real | 0.0 |
| -3.403E38 | 3.403E38 |
X1 | Auxiliary point | Real | 0.0 |
| -3.403E38 | 3.403E38 |
Y1 | Auxiliary value | Real | 0.0 |
| -3.403E38 | 3.403E38 |
X2 | Auxiliary point | Real | 0.0 |
| -3.403E38 | 3.403E38 |
Y2 | Auxiliary value | Real | 0.0 |
| -3.403E38 | 3.403E38 |
Output values
Pin | Description | Data Type | Default value | E.g. Engineering unit or Text group | Min. | Max. |
Out | Output | Real | 0.0 |
| -3.403E38 | 3.403E38 |
Application
Convert air flow in [m3/h] to [%] of the nominal air flow (and vice versa). Example: Operating value in [m3/h]; display value in [%] of the nominal value.
| x1 = | 0 | [m3/h] | x1 = | 0 | [m3/h] |
| x2 = | nominal | [m3/h] | x2 = | 100 | [m3/h] |
| y1 = | 0 | [%] | y1 = | 0 | [%] |
| y2 = | 100 | [%] | y2 = | nominal | [%] |
Process response
Standard (see General rules and information).
Troubleshooting
The block does not generate an error message.