Section 2: General operation
Model 2657A High Power System SourceMeter® Instrument Reference Manual
2-20
2657A-901-01 Rev. B/December 2012
Remote limit
The table below summarizes basic commands to program a limit. For a more complete description of
these commands, refer to the
Limit commands
Command Description
smua.source.limiti = limit
Set current limit.
smua.source.limitv = limit
Set voltage limit.
smua.source.limitp = limit
Set power limit.
compliance = smua.source.compliance
Test if in limit (
true
= in limit;
false
=
not in limit).
The following programming example illustrates how to set the current, voltage, and power limit to 50
mA, 200 V, and 1 W respectively:
smua.source.limiti = 50e-3
smua.source.limitv = 200
smua.source.limitp = 1
The following programming example illustrates how to print the limit state:
print(smua.source.compliance)
A returned value of
true
indicates one of three things:
•
If the instrument is configured as a current source, the voltage limit has been reached
•
If the instrument is configured as a voltage source, the current limit has been reached
•
The SMU is in sink limit.
Sink operation
Carefully consider and configure the appropriate output-off state, source, and compliance limits
before connecting the Model 2657A to a device that can deliver energy (for example, other voltage
sources, batteries, capacitors, or solar cells). Configure recommended instrument settings before
making connections to the device. Failure to consider the output-off state, source, and compliance
limits may result in damage to the instrument or to the device under test (DUT).
When operating as a sink (V and I have opposite polarity), the SourceMeter instrument is dissipating
power rather than sourcing it. An external source (for example, a battery) or an energy storage device
(for example, a capacitor) can force operation into the sink region.
The accuracy of the limit opposite in polarity from the source is diminished unless the instrument is in
sink mode. Also see
For example, if a 12 V battery is connected to the V-Source (HI to b) that is programmed for
+10 V, sink operation will occur in the second quadrant (V and measure -I).
CAUTION
NOTE
Summary of Contents for 2657A
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