Model 4200A-SCS Parameter Analyzer Reference Manual
Section 13: LPT library function reference
4200A-901-01 Rev. C / February 2017
13-83
rangeX
This command selects a range and prevents the selected instrument from autoranging.
Usage
int rangei(int
instr_id
, double
range
);
int rangev(int
instr_id
, double
range
);
instr_id
The instrument identification code
range
The value of the highest measurement to be made (the most appropriate range for
this measurement is selected); if
range
is set to 0, the instrument autoranges
Details
Use the
range
X
command to eliminate the time required by automatic range selection on a
measuring instrument. Because the
range
X
command prevents autoranging, an overrange condition
can occur (for example, when measuring 10 V on a 2 V range). The value 1.0e+22 is returned when
this occurs.
The
range
X
command can also reference a source, because a source-measure unit (SMU) can be
either of the following:
•
Simultaneously a voltage source, voltmeter, and current meter.
•
Simultaneously a current source, current meter, and voltmeter.
The range of a SMU is the same for the source and the measure commands.
Compliance limits – When selecting a range below the limit value, whether it is explicitly programmed
or the default value, an instrument temporarily uses the full scale value of the range as the limit. This
does not change the programmed limit value, and if the instrument range is restored to a value higher
than the programmed limit value, the instrument again uses the programmed limit value. See
(on page 3-3) for more information.
When changing the instrument range, be careful not to overrange the instrument. For example, a test
initially performed on the 10 mA range with a 5 mA limit is changed to test in the 1 mA range with a
1 mA limit. Notice that the limit is lowered from 5 mA to 1 mA to avoid overranging the 1 mA setting.
When source mode of the SMU changes, the measure range may change. This change minimizes
variations in the SMU output level. The source mode of the SMU refers to its voltage sourcing or
current sourcing capability. Changing the source mode means using a command (such as
force
X
) to
change the SMU mode from forcing voltage to forcing current (or from forcing current to forcing
voltage). For example, if the SMU is programmed to force voltage (
forcev
), and then is programmed
with to force current (
forcei
), to ensure a consistent output signal, the previously programmed
current measure range may change. Make sure the correct measure range is set by sending the
range
X
command after switching the source mode. The commands that can change the source
mode are
asweep
X
,
bsweep
X
,
force
X
,
pulse
X
,
search
X
, and
sweep
X
.
