Operator Manual Firmware Ver.3.05 and higher Instruction Manual

BOP-1K-GL 022814 3-7
3.3.5 MAXIMUM ACCEPTED VOLTAGE OR CURRENT (MAIN CHANNEL SOFTWARE LIMITS)
The software limits for the main channels (+Voltage Max, –Voltage Min, +Current Max and –
Current Min) are the maximum (positive) and minimum (Maximum negative) values allowable
for voltage and current. The default software limits are determined by the model: the nominal
(rated) values for voltage and current (e.g., 36V and 28A for the BOP 36-28GL). These four val-
ues can be adjusted independently. For example, a BOP 36-28GL, capable of delivering ±36V
in voltage mode can be configured to allow voltage to be adjusted only from –1V to +15V by
setting –Voltage Min to –1 and +Voltage Max to +15. To accomplish this via either GPIB or RS
232 ports send the following SCPI commands:
VOLT:LIM:POS 15 sets voltage positive limit to +15 volts
VOLT:LIM:NEG 1 sets voltage negative limit to 1 volt.
To ensure these settings are restored after a power cycle send MEM:UPD LIM and tag the
unit with the new power-up configuration. To restore factory default limits and undo the limits
saved by MEM:UPD LIM command, either perform a reset power-up (see PAR. 3.3.2.1) or
digitally query the limit(s), then digitally change them as needed, (if desired, save for power-
up using MEM:UPD LIM). Tag the unit with new power-up settings.
Similarly, a BOP 36-28GL, capable of delivering ±28A in current mode can be configured to
allow current to be adjusted from –0.5A to +10A by setting –Current Min to –0.5 and +Current
Max to +10. Adjustment range is between 0 and E
Onom
for voltage and 0 and I
Onom
for current.
Note that these software limits are not the same as the Protect Limits described in PAR. 3.3.6.
To accomplish this via either GPIB or RS 232 ports send the following SCPI commands:
CURR:LIM:POS 10 Sets current max limit to 10 Amperes.
CURR:LIM:NEG 5 Sets current min limit to 0.5 Amperes.
To ensure these settings are restored after a power cycle send MEM:UPD LIM and tag the
unit with the new power-up configuration. To restore factory default limits and undo the limits
saved by MEM:UPD LIM command, either perform a reset power-up (see PAR. 3.3.2.1) or
digitally query the limit(s), then digitally change them as needed, (if desired, save for power-
up using MEM:UPD LIM). Tag the unit with new power-up settings.
The main channel software limit values can be lowered (closer to zero) by the user, e.g., to pre-
vent inadvertent damage to a specific circuit under test. When the maximum/minimum values
are lowered, the unit will not accept values that exceed the new software limits. The main chan-
nel software limits are always in effect, for both analog control and digital control. If the user
attempts to program a value that exceeds the software limit using a digital command, the com-
mand is considered invalid and is disregarded: a 120 error is produced. If analog control is
enabled, the output is clamped to the software limit for programmed values higher than the soft-
ware limit.
If main channel software limits are changed from the default, the protection limits must
be changed to correspond to the new software limits (see PAR. 3.3.6). As an example,
changing +Voltage Max and –Voltage Min of a BOP 36-28GL to ±3V, respectively, causes the
unit to behave as if it was a BOP 3-28GL. 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. This is done by sending the following command.
VOLT:PROT:LIM 3.3 This sets both limits to 3.3 volts.