R&S FSMR, Operating Manual

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R&S FSMR Status Reporting System
1166.3363.12 5.17 E-1
Output Unit
The output unit collects the information requested by the controller, which it receives from the data base
management. It processes it according to the SCPI rules and makes it available in the output buffer.
If the instrument is addressed as a talker without the output buffer containing data or awaiting data from
the data base management, the output unit sends error message "Query UNTERMINATED" to the
status reporting system. No data are sent on the IEC bus, the controller waits until it has reached its
time limit. This behaviour is specified by SCPI.
Command Sequence and Command Synchronization
What has been said above makes clear that all commands can potentially be carried out overlapping.
In order to prevent an overlapping execution of commands, one of commands *OPC, *OPC? or *WAI
must be used. All three commands cause a certain action only to be carried out after the hardware has
been set and has settled. By a suitable programming, the controller can be forced to wait for the
respective action to occur (cf. Table 5-1).
Table 5-1 Synchronisation using *OPC, *OPC? and *WAI
Command Action after the hardware has settled Programming the controller
*OPC Setting the opteration-complete bit in the ESR - Setting bit 0 in the ESE
- Setting bit 5 in the SRE
- Waiting for service request (SRQ)
*OPC? Writing a "1" into the output buffer Addressing the instrument as a talker
*WAI Continuing the IEC-bus handshake Sending the next command
An example as to command synchronization can be found in Chapter "Program Examples".
For a couple of commands the synchronization to the end of command execution is mandatory in order
to obtain the desired result. The affected commands require either more than one measurement in
order to accomplish the desired instrument setting (eg autorange functions), or they require a longer
period of time for execution. If a new command is received during execution of the corresponding
function this may either lead to either to an aborted measurement or to invalid measurement data.
The following list includes the commands, for which a synchronization via *OPC, *OPC? or *WAI is
mandatory:
Table 5-1
Commands with mandatory synchronization (Overlapping Commands)
Command Purpose
INIT start measurement
INIT:CONM continue measurement
CALC:MARK:FUNC:ZOOM zoom frequency range around marker 1
CALC:STAT:SCAL:AUTO ONCE optimize level settings for signal statistic measurement
functions
[SENS:]POW:ACH:PRES:RLEV optimize level settings for adjacent channel power
measurements