Trigger Keyword Definitions

the sweep is initiated. This can happen on a continuous basis (INIT : CONT ON) or on a demand basis (INIT : CONT OFF). The functions of continuous and single sweeps are handled by this command. When the 1NIT:CONT ON command is given, the sweep is continuously re-initiated. When in the OFF state, the sweep is initiated with the INIT: IMMediate command.

Once initiated, the wait for trigger state is entered. Here, the trigger signal selected by the TRIG : SOURce command is examined until a TRUE condition is detected. These trigger signals are:

IMMediate

This

signal is always TRUE.

EXTernal

This

is the external trigger input jack. A positive

 

transition on this jack constitutes a TRUE signal.

BUS

This signal is the HP-IB <get> (Group Execute

 

Trigger) message or a ‘TRG command.

When a TRUE signal is found, the sweep is actually started.

The act of producing the sweep in some cases involves the use of trigger signals. For example, the stepped and list sweeps have modes that allow triggering for point-to-point advancement through the sweep. These trigger signals are selected by individual TRIG: SOURce commands in the appropriate subsystems (i.e. LIST:TRIGger:SOURce and SWEep:TRIGger:SOURce). The definition of these signals in the synthesizer cause the sweep to jump to the next point when the signal becomes TRUE, therefore the first point in the list or stepped sweeps is produced immediately upon starting the sweep. Receiving a trigger signal at the last point causes the IDLE state to be re-entered. Analog sweeps do not use the trigger signals during the sweep (although the trigger signals are needed to start the sweep as described).

The ABORt command resets any sweep in progress and immediately returns the instrument to the IDLE state.

The *WA1 , *OPC and *OPC? commands indicate a complete operation at the end of the sweep upon re-entry into the IDLE state.

Advanced Trigger Configurations

Because the SCPI layered trigger model is expandable, many more complex trigger configurations are possible.

The following paragraphs contain condensed definitions of the keywords used in the command tables. Many of the commands in trigger related subsystems are event commands. Remember that event commands cannot be queried. Similarly, event commands have no related *RST actions or settings. Event commands cause a particular action to take place inside the synthesizer.

l-l 12 Getting Started Programming