Siemens SINAMICS DCM Operating Instructions Manual page 458

Descriptions of functions
10.25 Connecting units in parallel and in series
Notes
● The control commands - switch-on/stop, operating enable, fast stop etc. - must also be
● The speed setpoint and the speed actual value must be entered at all substitute master
456
Notes:
 When commissioning, after carrying out the optimization (by starting optimization
runs, for example), all parameters set by the optimization runs must be transferred to
all substitute masters.
 Since the field supplies are connected in parallel, part of the overall motor-field
current flows through the freewheeling arm of the respective field power units with
disabled field firing pulses. For detecting the total motor field current (displayed at
parameter r50035), in the actual master, the free-wheeling current detected by the
"partner" device is therefore automatically added.
Therefore, for this operating mode, there must be an intact parallel connection as well
as an intact electronics power supply of the master and the substitute master – these
are prerequisites.
If this operating mode is also to be used after the electronics power supply of the
master or the substitute master fails, then the total motor field current actual value
must be externally sensed. The value must be supplied to the master and substitute
master using p50612.
 Generally speaking, the master function is only transferred from the active master to
the substitute master via telegram and an intact parallel interface. Even if the
master's electronic power supply fails, the master still has enough time to transmit a
telegram for the purpose of transferring the master function.
 As soon as the parallel connection is interrupted (by disconnecting the parallel
connecting cable), it can no longer guaranteed that the master/slave assignment will
be correct. The electronics power supply must be switched off and back on again at
all units!
entered at all of the substitute master units.
units.
Operating Instructions, 1.2012, C98130-A7066-A1-05-7619
SINAMICS DCM DC Converter