Fetch[1]|2|3|4 Queries - Keysight Technologies EPM-P Series Programming Manual

2 Measurement Commands

FETCh[1]|2|3|4 Queries

The FETCh? queries set the specified window's measurement function to either
single channel, difference or ratio measurements with relative mode either off or
on. 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 chapter 6, Format,
for further information.
The query returns a measurement result whenever it is valid. The measurement
result becomes 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 is valid. The
exceptions to this are, if the power meter is in the idle state and the data is invalid,
or the power meter 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 INT1, INT2 or EXT and a new acquisition has been initiated
NOTE
(using the INIT command for example), FETCH? waits until the trigger takes
place before executing. If trigger conditions are not satisfied—when the trigger
level differs greatly from the signal level for example—this can give the
impression that the power meter has hung.
To 'unlock' the power meter and adjust trigger settings, a GPIB bus execute
clear must be performed.
168 Keysight EPM-P Series Programming Guide