Remote Control Basics
R&S
®
EX-IQ-BOX
232
User Manual 1409.5570.32 ─ 05
Example:
Commands and queries in one message
The response to a query combined in a program message with commands that affect the
queried value is not predictable.
The following commands always return the specified result:
:FREQ:STAR 1GHZ;SPAN 100 :FREQ:STAR?
Result:
1000000000 (1 GHz)
Whereas the result for the following commands is not specified by SCPI:
:FREQ:STAR 1GHz;STAR?;SPAN 1000000
The result could be the value of
STARt
before the command was sent since the instru-
ment might defer executing the individual commands until a program message terminator
is received. The result could also be 1 GHz if the instrument executes commands as they
are received.
As a general rule, send commands and queries in different program messages.
Example:
Overlapping command with *OPC
The instrument implements
INITiate[:IMMediate]
as an overlapped command.
Assuming that
INITiate[:IMMediate]
takes longer to execute than
*OPC
, sending
the following command sequence results in initiating a sweep and, after some time, set-
ting the OPC bit in the ESR:
INIT; *OPC
Sending the following commands still initiates a sweep:
INIT; *OPC; *CLS
However, since the operation is still pending when the instrument executes
*CLS
, forcing
it into the "Operation Complete Command Idle" State (OCIS),
*OPC
is effectively skipped.
The OPC bit is not set until the instrument executes another
*OPC
command.
Example:
Overlapped command followed by non-conflicting commands
Suppose that the instrument is switched on to provide a real time test signal that requires
some calculation time. At the same time some settings for the configuration of a different
signal are made which do not interact with the generated signal (e.g. the signal may be
used later on). The signal generation and the signal configuration are independent from
each other, so none of the following overlapped commands needs to be synchronized:
SOUR:BB:3GPP:STAT ON
SOUR:BB:GSM:FORM FSK2
Command Sequence and Synchronization
Summary of Contents for EX-IQ-BOX
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