Siemens SINAMICS Series Operating Instructions Manual page 183

Cable, cable length, shield support:
The encoder cable capacitance must be recharged at each encoder edge change. The rms
value of this current is proportional to the cable length and pulse frequency, and must not
exceed the current permitted by the encoder manufacturer. A suitable cable that meets the
recommendations of the encoder manufacturer must be used, and the maximum cable
length must not be exceeded. Generally speaking, a twisted cable pair with a single pair
shield is sufficient for each track. This reduces crosstalk between the cables. Shielding all
the pairs provides protection against interference pulses. The shield should be connected to
the SINAMICS DC MASTER shield support over a large area.
Note
For connecting an incremental encoder see also Chapter "Applications (Page 705)".
Figure 6-59 Arrangement X178 and X179
Serial interface to AOP30/USS interface
Table 6- 37 Terminal X178
Terminal Function
X178
1 Supply (output)
2 Ground, AOP M
3 RX+/TX+
4 RX-/TX-
5 Ground, digital M
6 Ground, digital M
"Control Unit (CUD)" module
SINAMICS DCM DC Converter
Operating Instructions, 12/2018, A5E34763375A
6.9 Assignment of terminals and connectors
Technical specifications
24 V DC short-circuit proof, maximum load 200 mA
Internal supply related to internal ground terminal
Send and receive cable, RS485, two-wire
Positive differential input/output
Send and receive cable, RS485, two-wire
Negative differential input/output
Connecting
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