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13. Pulse Filtering
Oscillations in fluid systems manifest themselves through constant forward
and backward movements of the liquid column, which is also detected by the
rotor sensors and converted into proportional electronic pulses or edge se-
quences. Depending on the application, oscillations or vibrations can occur
during the flow rest phases or discontinuous flows. The pulses generated du-
ring the osciallation phase can be incorrectly interpreted by the downstream
evaluating unit or controller, which can be very distracting for the respective
operating process.
The signal filtering function of the internal electronics continuously offsets
these generated edges during the rapid forward and backward movements
Fig. 3: Pulse filtering principle
Table 4: Suppressed volume with pulse filtering activation
[ml]
Filter
FHG 1xx2
FHG 1xx4
position
0
0
1
0.145375
2
0.29075
3
0.436120
4
0.5815
5
0.726875
6
0.87225
7
1.017625
8
1.163
9
1.308375
10 (A)
1.45375
11 (B)
1.599120
12 (C)
1.7445
13 (D)
1.889875
14 (E)
2.03525
15 (F)
2.180625
FHG 1xx5
FHG 1xx7
0
0
0
0.7845
2.5
9.25
1.569
5.0
18.50
2.3535
7.5
27.75
3.138
10.0
37.00
3.9225
12.5
46.25
4.707
15.0
55.5
5.4915
17.5
64.75
6.276
20.0
74.00
7.0605
22.5
83.25
7.845
25.0
92.50
8.6295
27.5
101.75
9.414
30.0
111.00
10.1985
32.5
120.25
10.983
35.0
129.50
11.7675
37.5
138.75
of the rotor measuring unit. The signals at the channel outputs are also sup-
pressed at the same time until the internal offset is equalized or the initial
position of the rotor measuring unit has been reached again (see Fig. 3).
The user is able to set the degree of filtering in the form of partial volumes
using rotary coding switches.
Adjustable pulse filtering: 0Z, 0.25Z, 0.5Z, 0.75Z, 1.0Z, 1.25Z, 1.5Z, 1.75Z,
2.0Z, 2.25Z, 2.5Z, 2.75, 3.0Z, 3.25Z, 3.5Z, 3.75Z (Z: gear unit)
14. Programming the Preamplifier Electronics
The electronics elements are quickly and easily set. There are two rotary
coding switches on the electronics (S3, S4), a jumper (B2), a switch (S2)
and a key (S2). With the rotary coding switches, the IPF and the degree of
filtering are programmed.
B2
S1
S2
S4
S3
Fig. 4: Preamplifier electronics
148
11
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