HP 6038A Operating And Service Manual page 33

3-127 Current Setting. Current is programmed in either
amps or milliamps using any of the following codes (the value
10 is used as an example):
ISET 10
ISET 10A
ISET 10MA
3-128 The programmed current is the actual output if the
power supply is in CC mode, or the current limit if the power
supply is in CV mode.
3-129 The current setting may be read by sending:
ISET?
and addressing the power supply to talk.
3-130 The power supply can be instructed to measure its
actual output current by sending:
iOUT?
The results are placed on the HP-IB when the power supply
is addressed to talk, in this format (using 10 as an example):
IOUT 10.000
3-131 OVP Measurement. OVP trip voltage is hardware
set at the power supply front panel. The power supply can be
instructed to measure the OVP trip voltage by sending:
OVP?
The results are placed on the HP-IB when the power supply
is addressed to talk, in this format (using 60 as an example):
OVP K).000
3-132 Soft Limits. The power supply can be sent soft limit
values that place maximum limits on the voltage and current
programming values that will be accepted. If the power supply
receives a programming value that exceeds the soft limit, it will
ignore the command, turn on the ERROR indicator, and set
the ERR bits in the status register and in the serial poll register.
The power supply will not accept soft limit values that are lower
than present output values or values that are being held. The
largest soft limit values which can be sent are 61.425 V and
10.2375 A. These values also define the Initial condition.
3-133 Soft limits are programmed using any of the follow¬
ing codes (the values 15 and 10 are used as examples):
VMAX 15 IMAX 10
VMAX 15V IMAX 10A
VMAX 15MV IMAX 10MA
3-134 The soft limits may be read by sending:
VMAX? IMAX?
and addressing the power supply to talk. The response from
the power supply IS in this format (using 15 and 10 as examples):
VMAX 15.000 IMAX 10.000
3-1^ Delay. The power supply output may switch modes
or be unregulated momentarily after a new output value is pro¬
grammed or the output is reset from zero. In most cases this
temporary condition would not be considered a fault, and
foldback or a service request would be a nuisance. Delay
operates to mask CV, CC, and OR conditions from the fault
register for a specific period after a new output value is pro¬
grammed. The delay is initiated after the following commands:
OUT ON
RST
T, TRG, or Device Trigger
VSET OR ISET if hold is off
3-136 The power supply initializes with a delay of 0.5
seconds, which is appropriate in most cases. In some cases
a longer or shorter delay may be required. For example, when
up-programming output voltage with a very low current limit,
CC mode may persist longer than 0.5 seconds.
3-137 Factors that influence how long the mode change or
unregulated condition may last include: difference between old
output value and new output value, current or voltage limit,
and output (load) capacitance (for CV mode) or output Induc¬
tance (for CC mode). The delay required must be determined
empirically; the programming-response times in the specifica¬
tions table. Section !, can be used as guidelines.
3-138 Delay can be programmed in 1 ms increments using
either of the following codes (31999 used as an example):
DLY 31.999S
DLY 31999MS
3-139 Delay value may be read by sending:
DLY?
and addressing the power supply to talk. The response from
the power supply is in this format (using 0.5 as an example):
DLY 0.500
3-140 Note that during the delay period CV and CC are
masked from the foldback protection feature also. Delay does
not affect the setting of the CV, CC, or OR bits in the status
register or astatus register; delay affects only the setting of those
bits in the fault register. Delay does not affect conditions other
than CV, CC, or OR that may cause service request, nor will
delay affect CV, CC, or OR If they occur at any time other than
after a programmed output change.
3-141 Output On/Off. The power supply output can be
turned on and off using these commands:
OUT OFF or OUT 0
OUT ON or OUT 1
3-142 OUT OFF does not affect the voltage and current set¬
tings. OUT ON enables the power supply and returns the out¬
put to the present voltage and current settings, which can be
changed while the output is off. OUT ON will not reset OVP,
foldback protection, remote inhibit (INH) or fault line.
3-20