Model 4200A-SCS Parameter Analyzer Reference Manual
Section 13: LPT library function reference
4200A-901-01 Rev. C / February 2017
13-69
forceX
This command programs a sourcing instrument to generate a voltage or current at a specific level.
Usage
int forcei(int
instr_id
, double
value
);
int forcev(int
instr_id
, double
value
);
instr_id
The instrument identification code
value
The level of the bipolar voltage or current forced in volts or amperes
Details
The
forcev
and
forcei
commands generate either a positive or negative voltage, as directed by
the sign of the value argument. With both
forcev
and
forcei
commands:
•
Positive values generate positive voltage or current from the high terminal of the source relative
to the low terminal.
•
Negative values generate negative voltage or current from the high terminal of the source relative
to the low terminal.
The
forcev
command accepts both
CMTR1H
and
CMTR1L
for the
instr_id
parameter to support
differential CVU biasing. By forcing one polarity on CMTR1H and an opposite polarity on CMTR1L,
total bias can be up to 60 V, centered in relationship to ground. Note that it is not possible to exceed ±
30 V in relationship to ground.
When using the
limit
X
,
range
X
, and
force
X
commands on the same source at the same time in a
test sequence, call the
limit
X
and
range
X
commands before the
force
X
command. See
(on page 3-3) for details.
The ranges of currents and voltages available from a voltage or current source vary with the
instrument type. For more detailed information, refer to the hardware manual for each instrument.
To force zero current with a higher voltage limit than the 20 V default, include one of the following
calls ahead of the
forcei
call:
•
A
measv
call, which causes the 4200A-SCS to autorange to a higher voltage limit.
•
A
rangev
call to an appropriate fixed voltage, which results in a fixed voltage limit.
To force zero volts with a higher current limit than the 10 mA default, include one of the following calls
ahead of the
forcev
call:
•
A
measi
call, which causes the 4200A-SCS to autorange to a higher current limit.
•
A
rangei
call to an appropriate fixed current, which results in a fixed current limit.
Note that changing the source mode of the SMU can modify the measure range. If the sourcing mode
is changed from voltage to current sourcing (or from current to voltage sourcing), the measure range
may be changed to minimize variations in the SMU output level. See
(on page 13-83) for
recommended command order.
