Using The *Opc? Query - Tektronix TBS2000 Series Programmer's Manual

Status and Events
The program can now do different tasks such as talk to other devices. The SRQ,
when it comes, interrupts those tasks and returns control to this task.
/* Take amplitude measurement */
MEASUREMENT:IMMED:VALUE?

Using the *OPC? Query

The *OPC? query places a 1 in the Output Queue once an operation that
generates an OPC message is complete. The *OPC? query does not return until
all pending OPC operations have completed. Therefore, your time-out must be
set to a time at least if the longest expected time for the operations to complete.
The same command sequence using the *OPC? query for synchronization looks
like this:
/* Set up single sequence acquisition */
ACQUIRE:STATE OFF
SELECT:CH1 ON
ACQUIRE:MODE SAMPLE
ACQUIRE:STOPAFTER SEQUENCE
/* Acquire waveform data */
ACQUIRE:STATE ON
/* Set up the measurement parameters */
MEASUREMENT:IMMED:TYPE AMPLITUDE
MEASUREMENT:IMMED:SOURCE CH1
/* Wait until the acquisition is complete before taking the measurement*/
*OPC?
Wait for read from Output Queue.
/* Take amplitude measurement */
MEASUREMENT:IMMED:VALUE?
This is the simplest approach. It requires no status handling or loops. However,
you must set the controller time-out for longer than the acquisition operation.
TBS2000 Series Programmer 287