User manual

2400 Series SourceMeter
®
User’s Manual Source-Measure Concepts 6-7
Source-delay-measure cycle
In addition to static source and/or measure operation, SourceMeter operation can
consist of a series of source-delay-measure (SDM) cycles (Figure 6-1). During
each SDM cycle, the following occurs:
1. Set the source output level.
2. Wait for the source delay.
3. Make the measurement.
NOTE For the Model 2430 Pulse Mode, source delay is not used. The delays
used for Pulse Mode are covered in
Section 5.
See Section 11 for details on how the SDM cycle relates to the trigger
model.
Figure 6-1
Source-delay-measure (SDM) cycle
The delay phase of the SDM cycle allows the source to settle before the measure-
ment is performed. The delay period depends on how the source delay is config-
ured. The source delay can be manually set from 0000.00000 seconds to
9999.9990 seconds. If using auto delay, the delay depends on which source
range is presently selected, as summarized in Table 3-4; see Section 3 for details.
The manually set delay (up to 9999.999 sec) is available to compensate for longer
settling required by external circuitry. The more capacitance seen at the output,
the more settling time is required for the source. The actual delay period needed
can be calculated or determined by trial and error. For purely resistive loads and
at higher current levels, the programmable delay can be set to 0msec.
Auto*
(1msec)
Measure
End of A/D
Conversion
Source
Value
Trigger
Latency
(100µs)
Trigger
Delay
Start of A/D Conversion
* If enabled