447
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group • Tel.: Germany (06 21) 7 76-0 • USA (330) 4 25 35 55 • Singapore 7 79 90 91 • Internet http://www.pepperl-fuchs.com
Issue date 19.9.00
Zener barriers - Operating instructions
How to select the correct barrier
7.The follo wing points have to be clarified if spe cial field devi ces
are used.
• If the field device is a 4-20 mA transmitter: What load in
Ohms can be connecte d to t he transmitte r so t hat it ca n at-
tain 20 mA as before?
• If the field device is a current / pressure converter: What
load ca n be conn ected to the controlle r ca rd s o that it ca n
attain 20 mA as before?
• If the field device is a transmitter: How high is the load in
the safe area? (Typically, resistances of up to 250 Ohm are
used in the controller.).
NEW: In the near future, a barrier will be available with a
replaceable back-up fuse.
The introduction of a replaceable back-up fu se ahead of the
integrated fuse provides protection against faults which could
occur during the commissioning of the system. It is always
arranged that the outer fuse will respond before the inner, inn-
accessible fuse. The fuses used are specially intended for use
on barriers.
Z...
Type
Channels
Max.
Series resist-
ance
Uin
at 10 µA
Uin
max
Fuse rating External
fuse
Fuse supplied
by
LITTLEFUSE
Ohm V V mA mA
Z715.F 1 106 13 13.6 100 63 217,063
Z728.F 1327 27 28 80 50 217,05
Z728.H.F 1 250 27 28 80 50 217,05
Z765.F 2106
106
13
13
13.6
13.6
100
100
63
63
217,063
Z779.F 2327
327
27
27
28
28
80
80
50
50
217,05
Z779.H.F 2250
250
27
27
28
28
80
80
50
50
217,05
Z787.F 2 327
36 + 0.9V
27
27
28
28
80
80
50
50
217,05
Z787.H.F 2250
25+ 0.9V
27
27
28
28
80
80
50
50
217,05
Z960.F 2 64
64
6.5
6.5
9.5
9.5
80
80
50
50
217.05
Z961.F 2106
106
6.5
6.5
8.1
8.1
160
160
100
100
217.1
Z966.F 2 166
166
10
10
11.7
11.7
100
100
63
63
217.063