Operating instructions

SW 5250A•SW 3500A•SW 1750A Operation
Operation Manual 3-29
Although the DFI Fault is not included in the fault history log, any of the faults will cause
a DFI error to occur. When a DFI fault is tripped, either because one of the faults above
or a fault external to the SW, the output relay is opened, VPROGRAM is set to zero,
and an error message is displayed.

F3:OV Indicates that the internal DC bus has pumped up to a hazardous
level (due to sinking power rather than sourcing, i.e., attempting to
discharge a very large capacitor into the SW output too quickly).
Action: SW system opens relays and shuts off.
DC_ERR Indicates that an unacceptable level of DC voltage is present in the
output when the AC coupling is selected (i.e., a waveform with DC
content was selected when AC coupling was active).
Action: SW system opens relays and shuts off.
ROV Redundant Over Voltage: The peak value of the output voltage has
exceeded the maximum capacity of the SW.
Action: Opens relays and sets voltage amplitudes to zero; displays
error message.
OC SW output current reached IPROGRAM value.
Action 1: Limit Mode: folds back voltage to maintain constant
current; displays i in right-hand corner.
Action 2: Shutdown Mode: opens relays and displays error
message.
Action 3: Time-Out Mode: Constant current for a specified time,
then opens relay and displays error message.
48V:LOW Monitors internal housekeeping supply.
Action: Shuts off SW system.
GND_FLT Monitors output neutral.
Action: If greater than ± 20 volts with reference to chassis ground,
opens relays and displays error message.
Table 3–5 Fault Description and Action (FR1)