Pepperl+Fuchs Z-System - Page 22

2016-03
22
Z-System – Zener Barriers
Installation
3.3.2 Grounding with Multi-Channel Zener Barriers
Analog circuits are often connected to 2-channel zener barriers, see Figure 3.9.
Since there is no grounding on this type of circuit, the system is a quasi-floating
one. Because it is one zener voltage above the ground potential. Although it does
not actually float, the signal-to-noise ratio is improved.
A further advantage of multi-channel zener barriers is that a higher packing
density can be achieved.
Figure 3.8 Grounding with 1-channel zener barrier
Figure 3.9 Grounding with 2-channel zener barrier
Zone 2
Div. 2
Zone 0, 1, 2
Div. 1, 2
2
1
7
8
24 V
R
M
(+)
Power supply can
not be grounded.
4 mA ... 20 mA
transmitter
Zone 2
Div. 2
Zone 0, 1, 2
Div. 1, 2
24 V
R
M
(+)
3
1
6
8
2
7
4
5
4 mA ... 20 mA
transmitter