
Remote Control
R&S
®
RTM20xx
260
User Manual 1317.4726.02 ─ 01
Example: Overlapping command with *OPC
The instrument implements
SINGle
as an overlapped (asynchronous) command.
Assuming that
SINGle
takes longer to execute than
*OPC
, sending the following com-
mand 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.
15.1.5.1
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 15-2: 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