KEPCO BHK-MG 200W (Full Rack) Series - Manual (Page 25)

BHK-MG (OPR) 022014
1-9
1.4.4 OVERVOLTAGE/OVERCURRENT PROTECTION
Overvoltage and Overcurrent protection values can be individually programmed. The range for
overvoltage and overcurrent values are 0 to 1.1 x E
O
max, 0 to 1.1 x I
O
max. If the output volt-
age/current is maintained at or above the overvoltage/overcurrent protection value for more
than 9ms, the protection circuit latches the pass element off, discharges the output capacitor,
trips the POWER circuit breaker to OFF and sends a flag on a dedicated line (status port con-
nector). The default values are 1.1 x E
O
max for overvoltage protection, and 1.1 x I
O
max for
overcurrent protection. Refer to PAR. 3.2.11 for more information.
1.4.5 USER-DEFINED VOLTAGE/CURRENT LIMITS
The BHK-MG Power Supply can be programmed not to exceed user-defined values that can be
lower than the maximum values. For example, the BHK 500-0.4MG, which has maximum output
values of 500V d-c, 0.4A d-c, can be limited to 100V d-c, 0.1A d-c for working with circuitry that
might be damaged by higher levels. Once the limits are set, the power supply becomes, in effect
a 100V d-c, 0.1A d-c supply and values exceeding the limit values will not be accepted. Refer to
PAR. 3.2.12 for more information.
1.4.6 NONVOLATILE STORAGE OF PROGRAMMED SEQUENCES OR ACTIVE SETTINGS
The BHK-MG Power Supply contains 40 memory locations for each current range that can be
used either to preprogram a sequence of output values or to store active settings. For program-
ming sequences each memory location accommodates six parameters: output voltage, output
current, overvoltage, overcurrent, time (how long the parameters are in effect) and the next
address in the sequence. Values are stored in the nonvolatile memory, and are retained when
the unit is turned off. Refer to PAR. 3.2.16 for more information.
The same 40 memory locations are also available to save the active programmed settings (volt-
age, current, overvoltage, overcurrent). The saved setting can be recalled by specifying the
memory location. Refer to PAR’s. 3.2.13 and 3.2.14 for more information.
1.4.7 CURRENT SCALE
Output current of the power supply can be scaled down by a factor of 10, while at the same time
increasing the current resolution by a factor of 10. For example the BHK 500-0.4MG has maxi-
mum output values of 500V d-c, 0.4A d-c and a current resolution of 0.1mA d-c; scaling down
the output current results in a power supply with maximum values of 500V d-c, 0.04A d-c with a
current resolution of 0.01mA d-c. Current scaling is easily accomplished using the Menu. Refer
to PAR. 3.2.10 for more information.
Measurement of a decreasing output current of the power supply that falls below 8.98% ±0.01%
of the rated value is automatically measured with increased resolution/accuracy by a factor of
10 until the current rises above 9.69% ±0.01% of rated value.
The factory setting is for the high current range, shown on the top line of the LCD in command
entry status by the message “
Ihigh
.” The current scale setting is retained, and displayed upon
turn-on as either
Ihigh
or
Ilow.
1.4.8 FAST MODE/SLOW MODE SELECTION
BHK-MG Series Power Supplies can be configured by external strapping for either slow mode
operation with the internal output capacitor connected to the output, or fast mode operation with
the internal output capacitor disconnected from the output. The slow mode (default state) is rec-
ommended for voltage stabilization because of its low output noise and low recovery amplitude