MPE DP SERIES II, Operating And Service Manual

Page: 68 / 145

standby, phase loss, program line, fuse, over voltage, and over current. All diagnostic indicators
have memory retention which saves the fault condition until the power supply is reset. To clear
a fault condition, the user must press the clear key on the front panel with internal control or by
applying 5.0 V to terminal 18 of JS1 with external control. Alternatively, the supply can be
cleared by turning the power supply off and on.
Diagnostic functions and mode of control are embedded in the supply's closed loop control. The
power supply will operate using voltage control or current control depending on which setting is
lowest. Voltage control and current control also contain a soft start function which causes
voltage and/or current to ramp to the desired set point after power is initiated. The soft start
circuitry is reset upon power-on or operation of any diagnostic function.
Thermal overload indicates that the input power processing devices or output rectifiers have
reached a critical temperature. A resetting thermal breaker will reset upon cooling.
Standby indicates that the control circuits are powered, but the supply is disabled through the ac
contactor. This is the power supply's normal off condition. To start the supply, press the start
switch. To place the supply in standby, press the stop switch.
Phase loss indicates a problem with the power mains voltage.
Program line means the voltage set point, current set point, over voltage trip, or over current trip
external input is set beyond the range of control. These lines are constantly monitored and if any
of these references are set above the normal bounds, program line diagnostics will disable the
supply.
Fuse indicates that one of the three main fuses has cleared. Power must be removed from the
supply and the fuse must be replaced to correct this condition. A cleared fuse usually indicates a
failed power supply requiring factory attention.
Over voltage trip indicates that the supply has exceeded the over voltage trip reference. This
condition causes the supply to shutdown. To clear this condition, the user must press the clear
key on the front panel with internal control or by applying 5.0 V to terminal 18 of JS1 with
external control. To restart the supply, simply press the start switch.
Over current trip indicates that the supply has exceeded the over current trip reference. To clear
this condition, the user must press the clear key on the front panel with internal control or by
applying 5.0 V to terminal 18 of JS1 with external control. To restart the supply, simply press
the start switch.
A secondary over current trip diagnostic provides protection of internal circuitry due to abnormal
line and load conditions or due to failed internal circuitry. This over current trip condition
requires the control power to be recycled by toggling the power switch off and on.
55