KEPCO BOP 1KW-MG Operator Manual, Firmware Ver.2.01 to 2.37 - Manual (Page 75)

BOP HIPWR 022108
3-15
tion values (+25, –7) will remain in place until a new value is entered in the Voltage Protection
field. When a new Voltage Protect setting, e.g., 22V, is entered with BIPOLAR mode selected,
+Voltage Protect is set to +22V and -Voltage Protect to –22V.
NOTE: The use of remote programming (via RS 232 or GPIB) automatically asserts Indepen-
dent protection limits. Once the unit is returned to local mode, the unit is automatically
returned to BIPOLAR mode.
3.3.3.2 UNDERSTANDING VOLTAGE AND CURRENT PROTECT LIMITS
These values are the references for the complementary channels: voltage in current mode and
current in voltage mode. The range for these values is between a minimum (box) value (see Fig-
ure 1-2) and 1% above the rated nominal value (see PAR. 3.3.4.2). If the unit is in voltage mode,
it will enter current protect mode when the load demands more current and energy than permit-
ted by the ±current protect settings. Similarly, if the unit is in current mode, it will enter voltage
protect mode if the load demands more voltage and energy than permitted by the ±voltage pro-
tect settings. When the protect settings are exceeded, the protection channel limits the output, a
VPROTECT, CPROTECT or PROTECT (PROTECT may be seen only when external limits are
in use) message is displayed at the upper right of the LCD, and the power supply continues
operation.
3.3.3.3 HIDDEN VOLTAGE AND CURRENT PROTECT LIMITS
The BOP employs two back-up channels which function as safety backups if a main channel
fails. The backup channel limits are fixed and not user accessible. These limits are set to 5%
over the nominal (rated) values for voltage or current. If the software limits for a main channel is
changed (PAR. 3.3.4.1) the corresponding protect channel limit is automatically changed to be
5% of the nominal (rated) value above the user-programmed software limit.
3.3.4 CHANGING MAXIMUM OR MINIMUM SOFTWARE-CONTROLLED LIMITS
The maximum or minimum allowable voltage and current settings of the unit can be reduced
from the nominal using the Max/Min Settings menu. which lists the system’s software-controlled
voltage and current limits (+Voltage Max, –Voltage Min, +Current Max, –Current Min) as well as
the corresponding protection limits organized by operating mode. The default values of the sys-
tem limits are established by the Model: the nominal (rated) values for voltage and current and
1.01 x the nominal (rated) values for protection. The default values can be reduced by modifying
the highlighted parameter. The unit will not accept local or remote commands that exceed the
system limits. The system limits are always in effect, even when the unit is controlled by an
external reference.
If system limits are changed, the protection limits must be changed to
correspond to the new system limits. As an example, changing +Voltage Max and –Voltage
Min of a BOP 36-28MG to ±3V, respectively, causes the unit to behave as if it was a BOP 3-
28MG. In this case it is important to change the +V Protect Max and –V Protect Min limits (e.g.,
to ±3.3V, respectively) so that the load is protected when operating in Current Mode. System
limits are absolute values (do not use minus sign for negative limits).
The internal parameters +Current Protect Min and –Current Protect Max are displayed to com-
pletely define the permissible window when operating in Voltage mode. Similarly, +Voltage Pro-
tect Min, and –Voltage Protect Max are displayed to completely define the permissible window
for voltage when operating in Current mode.