Fig. 3-30 Rs485 Terminator; Uss Bus Configuration Via Com Link (Rs485) - Siemens MICROMASTER 420 Operating Instructions Manual

3 Functions
3.7.1

USS bus configuration via COM link (RS485)

Using MICROMASTER with RS485 communication requires a proper termination
at both ends of the bus (between P+ and N-), and correct pull up/ pull down
resistors at least one end of the bus (e.g. from P+ to P10, and N- to 0 V). (refer to
Fig. 3-30)
Fig. 3-30
When the MICROMASTER drive inverter is the last slave on the bus (refer to Fig.
3-31), and there are no other pull up/pull down resistors on the bus, the supplied
terminator must be connected shown in Fig. 3-30).
First Slave
Fig. 3-31
When the MICROMASTER is the first slave on the bus (refer to Fig. 3-31) the
RS485 Terminator may be used to terminate the bus by using P+ and N- only, for
the bus is powered by the last drive as explained.
NOTE
The supply for the pull up/ pull down resistors must be available whenever RS485
communication is in progress!
98
RS485 Terminator
RS485 Terminator
USS bus configuration
Last Slave
Master
e.g. PLC
RS485 Bus
MICROMASTER 420
Issue 07/04
RS485
Terminator
Operating Instructions
6SE6400-5AA00-0BP0