Keithley 2651A Reference Manual

Section 2: General operation Model 2651A High Power System SourceMeter® Instrument Reference Manual
2-66 2651A-901-01 Rev. A / March 2011
Maximum source values and readings
The full-scale output for each voltage and current source range is 101 percent of the selected range,
but the full-scale measurement is 102 percent of the range. For example, ±5.05 A is the full-scale
source value for the 5 A range, and ±102 mA is the full-scale reading for the 100 mA measurement
range. Input levels that exceed the maximum levels cause the overflow message to be displayed.
Note, however, that the instrument will autorange at 100 percent of the range.
Measure auto delay
The measure delay is a specific delay applied before each measurement is taken. This delay is
disabled by default (measurements are taken immediately). You can either change the default delay
by setting the smuX.measure.delay
(on page 7-195) attribute to a specific value or to an auto delay
setting (set smuX.measure.delay = smuX.DELAY_AUTO). If the measure delay is set to the auto
delay setting, a range-dependent delay is applied each time the instrument performs a current
measurement, or after changing current ranges during an autoranged measurement. The following
table contains the measure auto delays associated with each current range.
Range Measure auto delay
10 mA (and above)
0 μs (no delay)
1 mA
100 μs
100 μA 150 μs
10 μA 500 μs
1 μA
2.5 ms
100 nA 15 ms
You can increase or decrease the auto delay by changing the delay factor (for example, to reduce the
delay across all ranges by half, set smuX.measure.delayfactor = 0.5). For additional
information, refer to smuX.measure.delayfactor
(on page 7-196).
Ranging limitations
• Model 2651A: The maximum output power and source/sink limit for the Model 2651A is 202 W
per channel (maximum). With the 40 V (V-Source) range selected, the highest current
measurement range is 5 A. Refer to Operating boundaries
(on page 4-5) for power derating
information. When pulsing with the 50 A I-Source range selected, you can be at a larger voltage
range than 4 V dependent on your duty cycle. See Pulse duty cycle
(on page 3-27) for details.
• Source V Measure I or Source I Measure V: You can set source and measure ranges
separately, but if both source and measure functions are the same, the measure range is locked
to the source range.

Keithley 2651A Specifications

General

Brand	Keithley
Model	2651A
Category	Measuring Instruments
Language	English