INITiate Subsystem

May 24, 2006

Syntax Diagrams and Command Descriptions

Description

INITiate Command Functions

The INITiate subsystem is used to:

Start (activate) individual or multiple (concurrent) measurements.
Turn individual measurements off.
Determine the number of measurements currently active (INIT:COUNT?).
Determine the names of the measurements currently active (INIT:ON?).
Determine which measurements are finished (INIT:DONE?).

What Happens When a Measurement is INITiated?

When a measurement is started using INITiate commands, a new measurement cycle is started. If the selected measurement is currently in a measurement cycle, it is aborted. If a timeout is specified, the timeout period begins when a measurement is initiated.

NOTE

The INITiate subsystem is derived from SCPI, but has some modifications to make it more compatible with the manual operation of the test set. Most notably, the choice of single or continuous measurement triggering is made using the SETup subsystem.

INITiate Programming Examples (how INIT commands are used)

The INITiate command is used to start measurements.

INITiate commands allow multiple measurements to be started without waiting for other measurement processes to complete. For example, the following program example starts the Digital Average Power and Waveform Quality measurements, and then uses the INITiate:DONE? command in a loop to query the completion status of these measurements. See Measurement Event Synchronization .

As each measurement is completed, the FETCh command can be used to acquire the results, and the results entered into variables in the controlling application.

This program ends when the INITiate:DONE? command returns the string `NONE' indicating that all initiated measurements have gone through the measuring state see Measurement States .

The INIT:DONE? command is only useful when performing concurrent testing. When initiating only one measurement at a time, simply send the INITiate command immediately followed by the FETCh command to retrieve the results.

Trigger arming for each measurement is controlled in the SETup subsystem. The choices are single or continuous. The best practice (during remote operation) is to use single measurement mode. This simplifies the tasks of starting concurrent measurements, then using the INIT subsystem commands to determine which measurements are ready to be FETChed.

 
10       OUTPUT 714;"SETup:ALL:CONTinuous:OFF"
20       ! select single trigger mode for all measurements.
30       OUTPUT 714;"INITiate:DAPower;DOWQuality"
40       ! start digital average power and waveform quality measurements.
50       LOOP
60           OUTPUT 714;"INITiate:DONE?"
70           ! query to find out if any measurements are done.
80           ENTER 714;Meas_complete$
90           SELECT Meas_complete$
100           CASE "DAP"
110           ! test for the string "DAP" indicating
120           ! digital average power measurement is done.
130               OUTPUT 714;"FETCh:DAPower?"
140               ! query digital average power measurement.
150               ENTER 714;Dap_int;Dapower
160           CASE "DOWQ"
170           ! test for the string "DOWQ" indicating
180           ! that the waveform quality measurement is done.
190               OUTPUT 714;"FETCh:DOWQ:RHO?"
200               ! query rho.
210               ENTER 714;Rho
220           END SELECT
230       EXIT IF Meas_complete$="NONE"
240       END LOOP
250       PRINT Dapower
260       PRINT Rho
270       END