ETAS ES415.1 - Galvanically Isolation; Fig. 4-6 Maximum Input and Common-Mode Voltages

ES415.1 - User’s Guide24
Hardware Description ETAS
Fig. 4-6 Maximum Input and Common-Mode Voltages
All capacitors between the inputs (U
in+
and U
in-
) and case ground have the same
capacity. The maximum voltage between any input and case ground is also 60 V
DC/ 30 V AC.
Example
For the given input voltages U
inx
, U
iny
, U
inz
and the common-mode voltage U
CMxy
,
the maximum allowed common-mode voltage U
CMyz
is to be calculated.
U
inx
= 10 V
U
iny
= 5 V
U
inz
= 10 V
U
CMxy
= 15 V
max (U
inx
+ U
iny
+ U
inz
+ U
CMxy
+ U
CMyz
) = 60 V
10 V + 5 V + 10 V + 15 V + max (U
CMyz
) = 60 V
max (U
CMyz
) = 60 V - 40 V = 20 V
4.3.6 Galvanically Isolation
The sensor channels are galvanically isolated from each other and from the
power supply. The digitized transfer of the measurements on an Ethernet con-
nection implicitly results in a separation of the sensor channels from the supply
voltage.
+
-
+
-
+
-
Kanal x
Kanal y
Kanal z
Galvanische Trennung
Galvanische Trennung
Gehäusemasse
C
C
C
C
C
C
U
in+
U
in+
U
in+
U
in-
U
in-
U
in-
U
inx
U
iny
U
inz
U
CM x y
U
CM y z
U
c
U
c