Siemens SIMATIC S5 IP 281 Equipment Manual page 58

Hardware Settings
Selecting the
Plug– in jumpers X39/X49 are used to set the reference potential for the
reference potential
encoders.
for the encoder
The encoder interfaces can be operated as either 24 V interfaces or 5 V
(RS422). If the interface is adjusted, the corresponding reference potential
must beset to prevent the potential isolation between the 24 V area and the
5 V area from
r
2 – 12
being
removed.
x39
x49
X391X49
0 0 0
-
1 2 3
1 2
3
1 2
3
Incorrectly inserted jumpers can lead to interferences caused
by grounding loops. In addition, the potential isolation of the
24 V encoder inputs to the S5 is lost.
x39/x49
1 2
3
Reference potential for counter 1 (X5)
Reference potential for counter 2 (X7)
Meaning
Not permitted
0 Vew4 is connected to pin 7 24 V encoder
(X51X7).
I
Ml from S5 bus is con–
Meaning
O VeW4 is connected to pin 7
R 11/92
Use
RS 422 encoder
Use
24 V encoder