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9 setting output voltage or current, 10 changing current scale, Setting output voltage or current -8 – KEPCO BHK-MG 200W (Full Rack) Series User Manual

Page 52: Changing current scale -8, R. 3.2.10 fo

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3-8

BHK-MG (OPR) 022014

3.2.9

SETTING OUTPUT VOLTAGE OR CURRENT

V SET and I SET set output voltage and current limit, respectively, when the unit is in constant
voltage (CV) mode and set voltage limit and output current, respectively, when the unit is in con-
stant current (CC) mode. The mode (CV or CC) is determined by the load together with the pro-
grammed settings. As long as the voltage across the load produces a current that is less than
the I SET value, the unit operates in CV mode (voltage programmed to V SET value, current
limited by I SET value). If the load changes to the point that current through the load reaches the
I SET value, the unit automatically enters CC mode (current programmed to I SET value, volt-
age limited by V SET value).

With the power supply in command entry status

(:_:_:)

, press V SET (voltage) or I SET (cur-

rent) key to put the power supply in data entry status

(=_=_=)

. The lower right side of the LCD

shows the programmed setting in effect when the key is pressed. Press ENTER or CLEAR to
exit without changing setting. Enter new value (the

key erases data just entered) and press

ENTER to accept new setting or CLEAR to exit without changing setting.

NOTE: Although the LCD can display up to five decimal places, only two decimal places are

actually used for voltage and current settings (except that only one decimal place is
used for setting voltage on Models BHK 1000-0.2MG and BHK 2000-0.1MG, and three
decimal places are used for setting current on all models when current scale is set to
Low range.).

With the power supply in command entry status

(:_:_:)

, an alternative is to use

key

(increase) or

key (decrease) to change the output by the minimum increment (0.025% of

E

O

max for voltage, 0.025% of I

O

max for current). In CC mode, these keys control output cur-

rent; in CV mode they control output voltage. When the unit switches from constant current (CC)
to constant voltage (CV) mode, or from CV to CC mode the

and

keys are reassigned to

the active parameter. Once the transition point is reached, each press of the

key increases

voltage, then current, changing the mode, from CV to CC or from CC to CV. The

key has no

effect after the maximum (or programmed limit) has been reached. If the value entered exceeds
the maximum setting, the LCD bottom line flashes

VsetMAX=n.n V

or

IsetMAX=n.n mA

where n.n is the maximum setting (see PAR.3.2.12). The unit returns to {=_=_=) waiting for a
value that does not exceed the maximum.

3.2.10

CHANGING CURRENT SCALE

The full scale output current can be changed from the maximum current rating (factory default)
of the power supply (I

O

max) to a value ten times less (I

O

max/10): e.g., for the BHK 500-0.4MG

power supply the full scale current can be either 400mA or 40mA. The relative accuracy and
resolution are the same for both current programming scales because the power supply has two
independent sensing resistors and the calibration is done separately; relative readback accu-
racy and resolution are ten times better for I

O

max/10 scale.

The current scale setting is stored in non-volatile memory and retained when the unit is turned
off. When the unit is turned on, the stored current scale setting is in effect.

When the current scale is changed, the output is automatically turned off to avoid transients at
the output. After the scale has been changed, press OUTPUT ON/OFF key to enable the output
and restore the settings of the new current scale. Reprogram output voltage and current if the
RESET key was pressed,