Rohde & Schwarz SMB100A - Page 248

Remote Control Basics
R&S
®
SMB100A
232Operating Manual 1407.0806.32 ─ 13
Table 6-2: 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
4. Wait for a service request
The service request indicates that the overlapped command has finished.
*OPC? with a service request
1. Set bit no. 4 in the SRE: *SRE 16 to enable MAV service request.
2. Send the overlapped command with *OPC?
3. Wait for a service request
The service request indicates that the overlapped command has finished.
Event Status Register (ESE)
1. Set the OPC mask bit (bit no. 0) in the ESE: *ESE 1
2. Send the overlapped command without *OPC, *OPC? or *WAI
3. Poll the operation complete state periodically (by means of a timer) using the
sequence: *OPC; *ESR?
A return value (LSB) of 1 indicates that the overlapped command has finished.
Command Sequence and Synchronization