VEGA Z728 Zener barriers - Manual (Page 18)

18
Zener barriers - operating instructions
Application examples
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group • Tel.: Germany +49 621 776-0 • USA +1 330 4253555 • Singapore +65 67799091 • Internet http://www.pepperl-fuchs.com
Da
te of issu
e
05/2
3
/03
Wire strain gauges
If more than one strain gauge bridge is to be supplied from a
common power supply (in the example shown above there are
three), a possible solution is to supply them via two Z966s, as
shown. Both channels of these Zener barriers are arranged in parallel
in order to reduce the end-to-end resistance. This arrangement
provides 8 V to the bridges if the voltage supply is 20 V. The
system is approved for [EEx ib].
Hazardous area Safe area
Sensor +
Sensor -
350 Ohm
350 Ohm
350 Ohm
1
2
3
4
Z966
x3
x3
x3
8
6
x3
7
5
Z966
1
2
3
4
8
6
x3
x3
7
5
x3
x3
Z964
x3
x3
x3
x3
1
2
3
4
8
7
6
5
Z964
x3
x3
x3
x3
1
2
3
4
8
7
6
5
- 0 +