Flintec DAS 72.1 - Manual (Page 38)

C.4.5 Filter setting Commands – FM, FL, UR
Using the commands FM and FL, a digital filter type and strength can be set which will eliminate most of the
unwanted disturbances. Please note that these filters are positioned immediately after the A/D Converter
and therefore affect all aspects of the weighing operation.
FM Filter Mode FIR / IIR
Choose filter mode, permitted values are “0” for IIR and “1” for FIR.
Master ( PC / PLC ) sends DAS 72.1 responds Result
FM ¿ M+00001 Request: FM = 1 (FIR)
FM_0
¿ OK Setting: FM = 0 (IIR)
WP
¿ OK Setting saved
The digital IIR filter works as a low-pass filter of 2nd order with Gaussian characteristic, damping is 40
dB/decade; see table mode 0.
The digital FIR filter works as a low-pass filter with quick response; damping see table mode 1.
Factory default: 0
FL Setup filters
Command for setup cut off frequency, permitted values are 0 … 8.
Master ( PC / PLC ) sends DAS 72.1 responds Result
FL ¿ F+00003 Request: FL = 3
FL_1
¿ OK Setting: FL = 1
WP
¿ OK Setting saved
Filter values can be choosen between 0 and 8, see table below.
FL= 0 means no filter in mode 0 or 1 (command FM).
Factory default: 3
Mode 0 Characteristic (IIR-Filter)
FL Settling time to 0.1%
(ms)
3dB Cut-off frequency
(Hz)
Damping @300Hz
(dB)
Output-rate *
(samples/s)
0 no filtering ** 600
1 55 18 57 600
2 122 8 78 600
3 242 4 96 600
4 322 3 104 600
5 482 2 114 600
6 963 1 132 600
7 1923 0.5 149 600
8 3847 0.25 164 600
* Output-rate = 600/2 UR samples/s
** Antialiasing filter 17 Hz @ 60 dB/decade
Page 38 Manual DAS 72.1