ST_FTR_Notch
Configuration structure for the function block FB_FTR_Notch.
Syntax
Definition:
TYPE ST_FTR_Notch :
STRUCT
fNotchFrequency : LREAL;
fQ : LREAL;
fSamplingRate : LREAL;
nOversamples : UDINT;
nChannels : UDINT;
pInitialValues : POINTER TO LREAL;
nInitialValuesSize : UDINT;
END_STRUCT
END_TYPE
Parameter
Name | Type | Description |
---|---|---|
fNotchFrequency | LREAL | Notch frequency in Hz (greater than 0 and less than fSamplingRate/2) |
fQ | LREAL | Q-factor = fNotchFrequency/bandwidth (greater than zero) |
fSamplingRate | LREAL | Sampling rate fs in Hz (greater than zero) |
nOversamples | UDINT | Number of oversamples (greater than zero) |
nChannels | UDINT | Number of channels (greater than zero and less than 101) |
pInitialValues | Pointer to LREAL | Pointer to array with initial values (optional) |
nInitialValuesSize | UDINT | Size of the array with initial values in BYTE (optional) |
Configuration example
For example, you want to create a notch filter that strongly attenuates the frequency 100 Hz. In doing so, you allow a one-sided bandwidth of 10 Hz around these 100 Hz, i.e. you expect the -3 dB limit at 90 Hz and 110 Hz. Define for this:
fNotchFrequency := 100;
fQ := 10; (* B = fNotchFrequency/fQ = 10 Hz *)