Programming Examples - 4
139
INSTrument:NSELect 1
FETCh:VOLTage:AC?
INSTrument:NSELect 2
FETCh:VOLTage:AC?
INSTrument:NSELect 3
FETCh:VOLTage:AC?
Returning Voltage and Current Data From the Data Buffer
The MEASure and FETch queries can also return all 4096 data values of the instantaneous voltage and
current buffers. These are:
MEASure:ARRay:CURRent?
MEASure:ARRay:VOLTage?
Regulatory-Compliant Measurement of Quasi-Stationary Harmonics
In order to meet regulatory requirements of IEC-555 and other standards that specify how quasi-stationary
harmonics are to be measured, the ac source has a command that alters both the output frequency
control and the harmonic measurement algorithms to meet these requirements. The command is
SENSe:WINDow KBESsel | RECTangular
Triggering Measurements
You can use the data acquisition trigger system to synchronize the timing of the voltage and current data
acquisition with an external trigger source. Then use the FETCh commands to return different calculations
from the data acquired by the measurement trigger.The following measurement trigger sources can be
selected:
BUS selects GPIB bus triggers.
EXTernal selects the external Trigger In BNC connector.
TTLTrg selects the signal driving the Trigger Out BNC connector.
SCPI Triggering Nomenclature
As previously explained under "Triggering Output Changes", the ac source uses the following sequence
name and alias for the measurement trigger system. This alias can be used instead of the sequence form.
Sequence Form Alias
SEQuence3 ACQuire
Measurement Trigger System Model
Figure 4-2 is a model of the measurement trigger system. The rectangular boxes represent states. The
arrows show the transitions between states. These are labeled with the input or event that causes the
transition to occur.