09.02  Connection 
Siemens AG    6SE7087-6AK85-1AA0 
3-59 
Rectifier/Regenerating Unit    Operating instructions 
♦  Circuit identification: 
Circuit identification should be carried out successively
 on the 12-pulse master and on the 12-pulse slave. 
P052= 21 must be set on each unit for this purpose, and the switch-on command for the 12-pulse slave 
comes from the 12-pulse master (the control word wiring ensures that the partner unit, in each case, does 
not carry current or is held in the operating state r000= "--". 
•  Circuit identification procedure for 12-pulse master: 
Set P052= 21 on the 12-pulse master unit, switch on ⇒ circuit identification is carried out on the 12-pulse 
master  
•  Circuit identification procedure for 12-pulse slave: 
Set P052= 21 on the 12-pulse slave
 unit, switch on the 12-pulse master unit ⇒ circuit identification is 
carried out on the 12-pulse slave 
Note
: If circuit identification is carried out with the basic settings selected (operation as a 12-pulse slave, 
all control is from the 12-pulse master), the switch-on command must come from the 12-pulse master and 
the power terminals
 of the 12-pulse master unit must be connected to the supply voltage. 
Note
: When the reserve setting is selected on the 12-pulse slave unit (with appropriate parameterization 
of index i002 of the "Source selection parameters" P554, P555, ...) it is also possible to issue the switch-
on command for circuit identification on the slave unit on-site via the PMU or OP1S. 
 
♦  Setting additional functions: 
If required, activate the "auto restart" (via P366= 2) on the master and
 on the slave unit. This will be effective 
in the event of failure of the electronics supply voltage provided that the Peer-to-Peer telegram failure 
monitoring time has been switched off via P687.i003= 0. 
 
3.8.6 Redundancy mode 
If both rectifier/regenerating units are rated such that each separate
 unit is capable of carrying the full load 
current, the following possibilities are available with respect to redundant operation: 
 
•  Uninterrupted changeover of the 12-pulse master unit to stand-alone 6-pulse mode in the event of 
failure of the 12-pulse slave unit during 12-pulse mode: 
If the 12-pulse master
 is required to continue to run in "normal" stand-alone 6-pulse mode in the event of 
failure
 of the 12-pulse slave unit without interruption, "External fault 3" must not be "wired" to the Peer-to-
Peer interface, but instead the parameterization P573.i001 (or i002) = 1 is required on the 12-pulse master. 
If the master unit is also required to continue to run without an interruption in the event of failure of the Peer-
to-Peer interface cable, the Peer-to-Peer telegram failure monitoring time also has to be switched off via 
P687.i003= 0 on the master
. 
 
•  Reconnection of the 12-pulse slave unit during operation of the master: 
If (12-pulse) operation of a 12-pulse slave unit is required to be reinstated following an interruption of the 
Peer-to-Peer interface cable without error message and during (stand-alone 6-pulse) operation of the master 
unit, the Peer-to-Peer telegram failure monitoring time also has to be switched off via P687.i003= 0 on the 
12-pulse slave
 unit. 
 
•  Changeover of the 12-pulse slave unit to stand-alone 6-pulse mode in the event of failure of the 12-
pulse master unit: 
In the event of failure of the master unit during 12-pulse mode, it is possible for the 12-pulse slave unit to 
change over to stand-alone 6-pulse mode almost without interruption, because all external control 
commands that are wired to the terminals of the master unit (e.g. ON command) are also carried to the 
terminals of the 12-pulse slave unit. Externally implemented logic
 must ensure that in the event of failure of 
the master unit, the 12-pulse slave is switched from the basic to the reserve setting. The 12-pulse slave must 
be parameterized appropriately in the reserve setting to facilitate stand-alone 6-pulse mode with external 
control. The Peer-to-Peer telegram failure monitoring time also has to be switched off via P687.i003= 0 in 
this case. 
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