Trigger System

Overview

The trigger system is used to enable and initiate measurements or user- respectively full range calibrations.

Trigger States

The trigger has three possible states:

• Idle
• Waiting for Trigger
• Action

Idle

After Power ON, :ABORt or *RST the trigger is in the IDLE state. In the IDLE state no trigger signals are accepted and no measurement can be started. To leave the IDLE state, the trigger must be initiated. This can either be done by calling :INITiate[:IMMediate] (the trigger is initiated once) or by setting the trigger into the Continuous Mode (the trigger remains in the initiated mode after a measurement has finished). This can be done with the command INITiate:CONTinuous ON. Then the trigger state switches to Waiting for Trigger.

Performing a calibration can be seen as an exception of the typical trigger system behavior. Initiating a calibration (Calibrate commands) from the IDLE state is possible and switches the trigger system to the WAITING for trigger state and immediately to the ACTION state.

Waiting for Trigger

The device is waiting for an incoming trigger. If a trigger is recognized typically a measurement is started (the trigger state moves to Action). This can be achieved either by supplying an external trigger signal to the device or by sending one of the following commands:

Trigger commands (TRIG)

• *TRG
• :TRIGger[:SEQuence]:SINGle
• :TRIGger[:SEQuence][:IMMediate]

Additionally it is possible to perform a calibration out of the WAITING for trigger state:

Calibrate commands (CAL)

• :SENSe:CORRection:FULLrange:OPEN[:EXEcute]
• :SENSe:CORRection:FULLrange:SHORt[:EXEcute]
• :SENSe:CORRection:FULLrange:LOAD[:EXEcute]
• :SENSe:CORRection:FULLrange:THRU[:EXEcute]
• :SENSe:CORRection:USERrange:OPEN[:EXEcute]
• :SENSe:CORRection:USERrange:SHORt[:EXEcute]
• :SENSe:CORRection:USERrange:LOAD[:EXEcute]
• :SENSe:CORRection:USERrange:THRU[:EXEcute]
• :MMEMory:STORe:CORRection
• :MMEMory:LOAD:CORRection:FULLrange
• :MMEMory:LOAD:CORRection:USERrange

The device behaves slightly differently depending on the selected trigger command.

Command	Accepted trigger source	Awaitable with *OPC?
*TRG	BUS	no
:TRIGger[:SEQuence]:SINGle	BUS	yes
:TRIGger[:SEQuence][:IMMediate]	BUS | INTERNAL	no
Calibrate commands	BUS | INTERNAL	yes

Action

While in the Action state, the device is performing the selected measurement(s) or calibration(s). When the measurements are completed, the devices behavior depends on whether the trigger is in continuous mode or not (changeable with the INITiate:CONTinuous command). If the device is in the continuous mode, it immediately switches back to the WAITING for Trigger state, otherwise the device returns back to the IDLE state.

Trigger Sources

The trigger source specifies which sources the trigger system recognizes as a valid trigger source. It can be set with [TRIGger[:SEQuence]:SOURce]. Possible options are:

Trigger	Description
Bus Trigger	Generates a trigger when a SCPI/IEEE trigger command is executed (e.g. *TRG or :TRIG:SING).
Internal Trigger	Uses the internal trigger to generate continuous triggers automatically.
External Trigger (currently not supported)	Uses the signal from the EXT TRIGGER IN connector as trigger source (Bode 500 only).

Note

For a continuous measurement the Internal Trigger must be selected and the Continuous Initiation Mode must be enabled. With the internal trigger mode selected the device triggers itself automatically and with the continuous mode enabled the trigger state continuously switches between Action and Waiting for Trigger which results in a continuous measurement.

Commands

A summary of all commands related to the trigger system can be found in the following tables.

Command	Description
:INITiate:CONTinuous {ON|OFF|1|0}	enables or disables the triggers continuous initiation mode
:INITiate[:IMMediate]	changes the trigger state from Idle to Waiting for Trigger
*TRG	IEEE trigger command; generates a trigger if and only if the source is set to BUS
:TRIGger[:SEQuence]:SINGle	Generates a single trigger signal and can therefore be awaited
:TRIGger[:SEQuence][:IMMediate]	Generates a trigger signal but cannot be awaited
:TRIGger[:SEQuence]:SOURce {BUS|INTernal|EXTernal}	selects the trigger source

Following calibration related commands are also using the trigger system and its status bits:

Command	Description
:SENSe:CORRection:FULLrange:OPEN[:EXEcute]	Executes an OPEN calibration over the full frequency range
:SENSe:CORRection:FULLrange:SHORt[:EXEcute]	Executes a SHORT calibration over the full frequency range
:SENSe:CORRection:FULLrange:LOAD[:EXEcute]	Executes a LOAD calibration over the full frequency range
:SENSe:CORRection:FULLrange:THRU[:EXEcute]	Executes a THRU calibration over the full frequency range
:SENSe:CORRection:USERrange:OPEN[:EXEcute]	Executes an OPEN calibration over the frequency range configured by the user
:SENSe:CORRection:USERrange:SHORt[:EXEcute]	Executes a SHORT calibration over the frequency range configured by the user
:SENSe:CORRection:USERrange:LOAD[:EXEcute]	Executes a LOAD calibration over the frequency range configured by the user
:SENSe:CORRection:USERrange:THRU[:EXEcute]	Executes a THRU calibration over the frequency range configured by the user
:MMEMory:STORe:CORRection	Stores the current calibration data to the file system
:MMEMory:LOAD:CORRection:FULLrange	Loads a full-range calibration from the file system
:MMEMory:LOAD:CORRection:USERrange	Loads a user-range calibration from the file system

Relations to the status register system

During a trigger cycle different bits of the Operation Regsiter (OPER) are affected. If you want to read more about status registers please follow the link to the status register system. The interaction during time of the most important ones are shown in the following timing diagram.

Note

Loading calibration files are affecting the Calibrating state but NOT the Sweeping state of the OSR.