Model 2651A High Power System SourceMeter® Instrument Reference Manual
Section 2: General operation
2651A-901-01 Rev. A / March 2011
2-37
Remote power command
The programming example below illustrates how to obtain a power
reading
from smua:
reading
= smua.measure.p()
See for more commands necessary to set up source and measure functions and also
(on page 5-1) for more details.
Power programming example
The following programming example illustrates the setup and command sequence for a typical power
measurement procedure with the following parameters:
•
Source function: voltage, source autorange, 5 V output
•
Current measure function and range: current, auto
•
Current compliance: 50 mA
-- Restore Model 2651A defaults.
smua.reset()
-- Select voltage source function.
smua.source.func = smua.OUTPUT_DCVOLTS
-- Set source
smua.source.autorangev = smua.AUTORANGE_ON
-- Set voltage source to 5 V.
smua.source.levelv = 5
-- Set current limit to 50 mA.
smua.source.limiti = 50e-3
-- Set current range to auto.
smua.measure.autorangei = smua.AUTORANGE_ON
-- Turn on output.
smua.source.output = smua.OUTPUT_ON
-- Get power reading.
print(smua.measure.p())
-- Turn off output.
smua.source.output = smua.OUTPUT_OFF
Contact check measurements
Overview
The contact check function prevents measurements that may be in error due to excessive resistance
in the force or sense leads when making remotely sensed (Kelvin) measurements. Potential sources
for this resistance include poor contact at the device under test (DUT), failing relay contacts on a
switching card, and wires that are too long or thin. To use contact check, the current limit must be at
least 1 mA (this allows enough current to flow when performing the test), and the source-measure unit
(SMU) must not be in High-Z output-off mode.
The contact check function will also detect an open circuit that may occur when a four-point probe is
misplaced or misaligned. This relationship is shown schematically in Contact check commands,
where R
C
is the resistance of the mechanical contact at the DUT, and R
S
is the series resistance of
relays and cables.
