HBK CB1010, Operating Manual

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CANHEAD
CANHEAD ENHANCEMENTS
48
Complete filters for 250 kBaud and 500 kBaud
Nom. (rated)
value (Hz)
­3 dB (Hz) ­1 dB (Hz) Delay time
(ms)
Sampling rate
(S/s)
25 23.2 13.1 13.3 300
15 15.5 8.8 20.0 200
10 10.43 5.94 33.3 300
7 6.952 3.949 50.0 200
5 5.08 2.9 76.7 150
3 3.386 1.930 115.1 100
2.5 2.523 1.439 163.3 75
1.5 1.682 0.959 245.0 50
1.25 1.259 0.718 336.6 37.5
0.8 0.840 0.479 504.9 25
0.6 0.697 0.359 683.3 18.75
0.4 0.120 0.240 1025 12.5
0.15 0.1623 0.0910 1712 300
0.1 0.108 0.061 2568 200
0.08 0.0811 0.0455 3411 300
0.05 0.0542 0.0304 5116 200
0.04 0.0406 0.0227 6814 150
0.025 0.0271 0.0152 10221 100
Filters below 0.15 Hz use a different algorithm internally, which makes the sampling rate
high.
Added to the filter delay time is a latency time for CAN bus transmission. This is 1/(max­
imum possible data rate).
Example: The transport time required for 6 modules at 500 kBaud is 10 ms.
The following applies to the data rate and filter selection:
S
The 3 dB cut‐off frequency should be below the data rate by at least factor 6
S
Selecting a data rate above the internal sampling rate only wastes resources, the
same measured value is then transmitted many times
S
The data rate and the sampling rate should have integer divisors, so that samples can­
not be duplicated or omitted