User manual

Remote Control
R&S
®
RTO
404User Manual 1316.0827.02 ─ 06
Example: Overlapping command with *OPC
The instrument implements SINGle as an overlapped command. Assuming that
SINGle takes longer to execute than *OPC, sending the following command sequence
results in initiating a sweep and, after some time, setting the OPC bit in the ESR:
SINGle; *OPC.
Sending the following commands still initiates a sweep:
SINGle; *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.
16.1.5.1 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.
Table 16-2: Synchronization using *OPC, *OPC? and *WAI
Com-
mand
Action Programming the controller
*OPC Sets the Operation Complete bit in the ESR
after all previous commands have been execu-
ted.
●
Setting bit 0 in the ESE
●
Setting bit 5 in the SRE
●
Waiting for service request (SRQ)
*OPC? Stops command processing until 1 is returned.
This is only the case after the Operation Com-
plete bit has been set in the ESR. This bit indi-
cates that the previous setting has been com-
pleted.
Sending *OPC? directly after the command
whose processing should be terminated before
other commands can be executed.
*WAI Stops further command processing until all
commands sent before *WAI have been exe-
cuted.
Sending *WAI directly after the command
whose processing should be terminated before
other commands are executed.
Command synchronization using *WAI or *OPC? appended to an overlapped command
is a good choice if the overlapped command takes only little time to process. The two
synchronization techniques simply block overlapped execution of the command.
For time consuming overlapped commands it is usually desirable to allow the controller
or the instrument to do other useful work while waiting for command execution. Use one
of the following methods:
*OPC with a service request
1. Set the OPC mask bit (bit no. 0) in the ESE: *ESE 1
2. Set bit no. 5 in the SRE: *SRE 32 to enable ESB service request.
3. Send the overlapped command with *OPC
Basics