Fetch[1] - Agilent Technologies U2000 Series Manual

2 MEASurement Commands

FETCh[1]?

The FETCh? queries set the current window's measurement function. This can
be only set to single measurement. They then recalculate the measurement
and place the result on the bus. The format of the result is set by
FORM[:READ][:DATA]. Refer to
for further information.
The query returns a measurement result when it is valid. The measurement
result is invalid under the following conditions:
• When *RST is executed.
• Whenever a measurement is initiated.
• When any SENSe parameter, such as frequency, is changed.
If data is invalid, the FETCh? query is not completed until all data becomes
valid. The exceptions to this are, if the power sensor is in the idle state and the
data is invalid, or the power sensor has been reconfigured as defined above
and no new measurement has been initiated. In such cases, the FETCh?
routine generates the error –230, "Data corrupt or stale" and no result is
returned. A common cause for this error is receiving a FETCh? after a *RST. If
the expected value and resolution parameters are not the same as those that
were used to collect the data, error –221, "Settings conflict" occurs.
When TRIG:SOUR is EXT and a new acquisition has been initiated (using the INIT command
N O T E
for example), FETCH? waits until the trigger takes place before executing. If triger conditions are not
satisfied - when the trigger level differs greatly from the signal level for example - this can give the
impression that the power sensor has hung.
To unlock the power sensor and adjust trigger settings, an execute clear (*CLS) must be performed.
74
Chapter 5, "FORMat Subsystem," on page 119
U2000 Series Programming Guide