Rockwell Automation SA3000 High Power Modules - Manual (Page 58)

B-2 High Power SA3000 Power Modules
The programmer initiates control of the charging process by setting the BUS_ENA@
bit (register 100/100, bit 4). Normally, the PMI processor waits for the rising edge of
this bit to start the process. However, if this bit is ON at power-up, the PMI processor
will interpret this as a positive transition. The DC bus controller, though, will inhibit the
system’s state machine until valid configuration and gain data is received.
Note that the BUS_ENA@ bit must be turned on before the programmer enables the
bridge test or the inner control loop in the PMI processor in register 100/1100. If
BUS_ENA@ is not enabled first, an interlock error will occur (register 205.1205, bit 6,
IC_BUS@) and the drive will not be permitted to execute either the bridge test or the
control loop.
In response to the rising edge of the BUS_ENA@ bit, the PMI processor will allow the
bus voltage to rise above the undervoltage threshold and then close the pre-charge
contactor. This will short out the pre-charge resistors. The PMI processor will set
BUS_RDY@ (bit 4 in register 200/1200) when all of the following conditions have
occurred:
• the internal DC bus has been enabled via the BUS_ENA@ input
• the internal DC bus voltage has reached the level specified in the tunable variable
UVT_E0%
• the internal DC bus voltage is at a steady state
• the pre-charge contactor has closed
Important: The BUS_ENA@ bit must remain on during the bridge test or the
execution of the control algorithm in the PMI processor, or the pre-charge
contactor will open and the drive will shut down.
If BUS_ENA@ is turned off at any time, power to the power device gates is shut off.
Approximately one second later, the pre-charge contactor is opened. If the pre-charge
contactor closes when it is not commanded to do so by the PMI processor, register
202/1202, bit 6 (FLT_CHG@) is set and the drive is shut down. (Auxiliary contacts on
the pre-charge contactor are used to verify that the pre-charge contactor is open or
closed. These auxiliary contacts are pre-wired and require no connection by the user.)
There is a time limit of 10 seconds from the time when the rising edge of the
BUS_ENA@ input is detected to the time when the bus voltage must reach the steady
state voltage specified in the tunable variable UVT_E0% and the auxiliary contact is
required to close. (See the following section for more information on tunable variable
UVT_E0%.) If this time limit is exceeded, the pre-charge contactor is opened and the
FLT_CHG@ bit (register 202/1202, bit 6) is set. If the bus voltage recovers to the
appropriate level within 10 seconds, the pre-charge contactor will be closed and the
drive will resume operation.
Refer to figure B.2, the internal DC bus control state diagram (with pre-charge option
supplied), for more detailed information.