Rockwell Automation SA3100 Diag,Troublesht,Startup,Guide - Manual (Page 21)

Diagnostics and Troubleshooting 2-7
2.5 Internal DC Bus Diagnostics
The status of the DC bus is monitored as part of both the interlock and run-time
diagnostics. The DC bus is considered “ready” when the PMI Regulator detects that
the bus voltage is greater than the undervoltage threshold value stored in local
tunable UVT_E0% and has reached a steady state, and the pre-charge contactor has
closed. This is checked as an interlock test and is then constantly monitored during
run-time diagnostics. A complete description of the DC bus pre-charge sequence is
provided in the SA3100 Power Modules instruction manual (S-3058). For further
details regarding a DC bus fault, see the extended status register 222 (1222).
2.5.1 DC Bus Monitoring During Bridge Test Mode
If bus voltage drops below the value stored in the undervoltage warning threshold
tunable (UVT_E0%) while the PMI Regulator is in bridge test mode, the PMI Regulator
will issue a drive warning (203/1203, bit 1, WRN_UV@). If bus voltage continues to
drop below the value stored in the power loss fault threshold local tunable
(PLT_E0%), the pre-charge contactor will open. While the pre-charge contactor is
open, the gates are disabled, and the bridge test is not functional.
If bus voltage does not return to the proper level within 10 seconds, a Bus Charge
Time-out fault (register 202/1202, bit 6, FLT_CHG@) will occur, and the drive will shut
down. If bus voltage returns to the proper level within 10 seconds, the bridge test will
return to normal operation.
2.5.2 DC Bus Monitoring During Torque Minor Loop Mode
If bus voltage drops below the value stored in the undervoltage warning threshold
tunable (UVT_E0%) while the PMI Regulator is in torque minor loop mode, the PMI
Regulator will limit torque in order to avoid further drop in DC bus voltage and issue a
drive warning (203/1203, bit 1, WRN_UV@). If bus voltage continues to drop below
the value stored in the power loss fault threshold local tunable (PLT_E0%), the
pre-charge contactor will open. While the pre-charge contactor is open, the gates of
the power devices are disabled, and the motor will begin to coast to stop.
If bus voltage returns to the nominal configured value within 10 seconds of the bus
voltage dropping to less than the value stored in the power loss fault threshold local
tunable, the pre-charge contactor will automatically close and the PMI Regulator will
return to using the torque reference currently being requested by the UDC. If bus
voltage does not return to the nominal configured value within 10 seconds, a Bus
Charge Time-out fault (register 202/1202, bit 6, FLT_CHG@) will occur, and the drive
will shut down.