Keithley 2461, Reference Manual, Page: 150 / 1109

Model 2461 Interactive SourceMeter® Instrument Reference Manual Section 2: General operation
2461-901-01 A/November 2015 2-123
With a source voltage of 10 V and a DUT resistance of 10 Ω , the current through the DUT should be:
10 V / 10 Ω = 1 A. However, because the limit is set to 10 mA, the current will not exceed 10 mA, and
the voltage across the resistance is limited to 100 mV. In effect, the 10 V voltage source is
transformed into a 10 mA current source.
In steady-state conditions, the set limit restricts the instrument output unless there are fast transient
load conditions.
If the source output exceeds the source limit:
•
On the Home screen, LIMIT is displayed to the right of the source voltage.
•
The Source value changes to yellow.
The source is clamped at the maximum limit value. For example, if the measurement limit is set to 1 V
and the measurement range is 2 V, the output voltage is clamped at 1 V.
For additional details on using limits, see
Operating boundaries (on page 4-4).
Setting source limits
Using the front panel:
1. Press
FUNCTION
and select the source and measurement combination.
2. On the Home screen, select the button next to Limit.
3. Set the value.
4. Select
OK
.
Using SCPI commands:
To set the limit when sourcing current, send the command:
SOURCe:CURRent:VLIMit <n>
Where
<n>
is the current limit value.
To set the limit when sourcing voltage, send the command:
SOURCe:VOLTage:ILIMit <n>
Where
<n>
is the voltage limit value.
Using TSP commands:
To set the limit when sourcing current, send the commands:
smu.source.func = smu.FUNC_DC_CURRENT
smu.source.vlimit.level = limitValue
To set the limit when sourcing voltage, send the commands:
smu.source.func = smu.FUNC_DC_VOLTAGE
smu.source.ilimit.level = limitValue
Where
limitValue
is the limit value.