HBM Genesis GEN5i User Manual page 252

252
Looking at Figure 12.5 the GN610 specifies U IN(+), U IN(-) and |Uiso| ≤ 1 kV.
Using a standard passive 10:1 probe in combination with the GN610 gives the
situation as shown in Figure 12.6.
Figure 12.6: Isolated balanced input channel with passive probe
Example1:
In this setup U IN(-) is not divided, so it is required that |U IN(-)| ≤ 1 kV. Assuming
U IN(-) is connected to 0 V we can calculate the voltages at U
Assuming:
U IN(-) = 0V
10:1 probe used, probe input Voltage applied is 10* U
Results in: U IN(+) = 10 * U
U = 10 * U
iso
Due to the 2 MΩ impedance between U IN(+) and U IN(-) the probe doesn't
divide by 10, but by 5.5 (10 / 1.82). So in case the maximum specified U
1 kV is considered this smaller division factor results the U IN(+) level to be way
above the channels specification.
Example2:
Since U IN(-) is not divided, there are very strict consideration on how signals
can be attached. Assume the U IN(+) and U IN(-) are reversed by accident. We
can calculate U and U IN(-).
iso
/ 11M * 2M = 1.82 * U
diff
/ 11M * 1M = 0.91 * U
diff
GEN5i
and U IN(+)
iso
diff
diff
diff
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I2679-4.0 en
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