
GLDM 64.1 Technical Manual rev. 1.30 February
2020
Page 20 of 50
6.4.
Filter Setting Commands
– FM, FL, UR
A digital filter can be set which will eliminate most of the unwanted disturbances. The commands
FM
and
FL
are used to define the digital filter settings, the command
UR
is used to define an averaging of up to 128
measurement values. Please note that these filters are positioned immediately after the A/D Converter and
therefore affect all aspects of the weighing operation.
8.4.1. FM Filter Mode
[ SDO 2100 sub 09 ]
This command defines the filter mode. Choose the filter mode for your application.
Permitted values
are “0” for IIR filter and “1” for FIR filter.
Master (PC / SPS) sends
Slave (GLDM 64.1) responds
Meaning
FM
M+00000
Request: FM = 0 (IIR filter)
FM0
OK
Setup: FM = 0 (IIR filter)
WP
OK
Setup saved
The digital IIR filter operates as 2
nd
order low pass filter and Gaussian characteristics. The attenuation is
40dB/decade (12 dB/octave).
The digital FIR filter works as a low-pass filter with quick response; damping see table mode 1.
Factory default:
0 (IIR filter)
8.4.2. FL Filter setting
[ SDO 2100 sub 04 ]
This command defines the 3dB filter cut-off frequency.
Master (PC / SPS) sends
Slave (GLDM 64.1) responds
Meaning
FL
F+00003
Request: FL = 3 (4 Hz)
FL1
OK
Setup: FL = 1
WP
OK
Setup saved
The permitted settings are from 0 to 8 (see below table).
Factory default
: 3.
Mode 0 (IIR filter) Settings / Characteristics
FL
Settling time to 0.1%
(ms)
3 dB Cut-off
frequency (Hz)
Damping @ 300 Hz
(dB)
Output rate*
(samples/s)
0
No filtering
**
1172
1
55
18
57
1172
2
122
8
78
1172
3
242
4
96
1172
4
322
3
104
1172
5
482
2
114
1172
6
963
1
132
1172
7
1923
0.5
149
1172
8
3847
0.25
164
1172
* Output rate = 1172/2
UR
samples/s
** Pre-filter 18 Hz
** Note
: The pre-filter can be switch ON and OFF with the command
PF
– settings are 0 (OFF) or 1 (ON).
-
This feature can be used with ASCII communication or CANbus
[ SDO 2100 sub 16 ]
.
-
The use is for specialists only.