Remote Control Basics
R&S
®
SMU200A
477Operating Manual 1007.9845.32 ─ 15
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
Example: Overlapped command followed by conflicting commands
Suppose that the generator is switched on to provide a real time test signal that requires
some calculation time. This signal is to be added to a waveform from the second base-
band generator. In this case the application program must ensure that the real signal is
actually available in the added signal before further action is started. This involves an
appropriate synchronization technique for the first command (the following sseqzuence
assumes an appropriate routing):
SOUR:BB:3GPP:STAT ON
The instrument waits until command has finished.
SOUR2:BB:GSM:STAT ON
Depending on the selected synchronization techniques, non-conflicting commands can
be executed while waiting until the synchronized overlapped command has finished.
6.4.1 Preventing Overlapping Execution
To prevent an overlapping execution of commands, one of the commands *OPC, *OPC?
or *WAI can be used. All three commands cause a certain action only to be carried out
after the hardware has been set. By suitable programming, the controller can be forced
to wait for the corresponding action to occur.
Command Sequence and Synchronization
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