LPFIL ( First Order Low Pass Filter )
Function name | LPFIL_010 |
---|---|
Function version | 1.0 |
Function state | stable |
Compatibility with IEC61131-3 | not compatible |
Graphic symbol :
Input / Output :
Name | Belonging Group | Access | Types of data | Description |
---|---|---|---|---|
Active | Left Power Flow | State of activation/deactivation filter intervention | ||
IN | Normal | W , RW | F , B , W , L , S | Variable to filter |
TS | Normal | W , RW | F , B , W , L , S | Sample time filter |
TAU | Normal | W , RW | F , B , W , L , S | Tau filter |
Q | Normal | W , RW | F , B , W , L , S | Filtered value |
Description :
The function block LPFIL is used to obtain a first order low pass filter. If the input Active (power flow) is ON in Q you’ll have the filtered value of IN, otherwise you’ll have the value of direct IN beyond the loading of the filter. IN must have values comprised between –32768 and +32767. The time constant of the filter is defined in the input TAU (in ms). Suppose to start from an input value of zero, the output Q of the filter will get a value of 63% of the input after the time TAU.
The function block LPFIL contains a timer inside make the filter work at each sample time. This sample time is set through the input TS (in ms).