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Annex
NRP2
385
User Manual 1173.9140.02 ─ 07
Example:
The following sequence of commands provides the difference between measured val-
ues from sensors 1 and 2 by means of
FETCh:DIFF?
, which measure in the ContAv
mode as the default setting.
CONF:DIFF
INIT:ALL
FETCh:DIFF?
'Response: valid result
FETCh:RAT?
'Response: valid result
FETCh:BURst?
'Response: -221, "Settings conflict"
The
FETCh:RAT?
command then delivers the ratios of the two measured values. This
is possible without a new measurement, since the required data is available. The last
FETCh
command requires a result that was measured in the BurstAv mode. Such a
measured value is not available and thus, this command will generate a SCPI error
(-221, "Settings conflict").
FETCh?
immediately delivers a measured value if a valid result is available. If no mea-
sured value is available, the R&S
NRP2 waits for such a value and then answers the
query. During this time, no other command should be sent to the R&S
NRP2, since the
query has to be answered first. If a command is sent to the R&S
NRP2, the SCPI error
-410, "Query interrupted", is output.
However,
FETCh?
should wait only if a measurement result is expected, since com-
mand processing is blocked if a command is not answered. If
FETCh?
is executed
although no measured values are expected, the SCPI error -214, "Trigger deadlock", is
output. This may occur if the trigger source is set to
BUS
or
HOLD
with low-level
TRIG:SOUR
and
FETCh?
immediately follows
INIT
.
Example
CONF
TRIG:SOUR BUS
INIT
FETCh?
'Response: -214, "Trigger deadlock",
*TRG
or
GET
is not possible if
FETCh?
is waiting.
A.4.2 Trigger state system
The accuracy of a result largely depends on how accurately the sequence of a mea-
surement can be determined. TheR&S
NRP2 manages a trigger state system to SCPI
1999.0 for each sensor to define the exact start and stop time of a measurement. This
system defines the sequence of a measurement cycle. 4 different device states are
defined in the trigger state system implemented in the R&S
NRP2.
Programming Measurements
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