Data Acquisition Toolbox

Defining a Trigger: Trigger Types

Defining a trigger for an analog output object involves specifying the trigger type with the TriggerType property. You can think of the trigger type as the source of the trigger. The analog output TriggerType values are given below.

Table 6-8: Analog Output TriggerType Property Values

TriggerType Value	Description
{Immediate}	The trigger occurs just after you issue the start function.
Manual	The trigger occurs just after you manually issue the trigger function.

Trigger types can be grouped into two main categories:

• Device-independent triggers
• Device-specific hardware triggers

The trigger types shown above are device-independent triggers because they are available for all supported hardware. For these trigger types, the callback that initiates the trigger event involves issuing a toolbox function (start or trigger). Conversely, device-specific hardware triggers depend on the specific hardware device you are using. For these trigger types, the callback that initiates the trigger event involves an external digital signal.

Device-specific hardware triggers for National Instruments and Agilent Technologies devices are discussed in Device-Specific Hardware Triggers. Device-independent triggers are discussed below.

Immediate Trigger.   If TriggerType is Immediate (the default value), the trigger occurs immediately after the start function is issued. You can configure an analog output object for continuous output, by using an immediate trigger and setting RepeatOutput to inf.

Manual Trigger.   If TriggerType is Manual, the trigger occurs immediately after the trigger function is issued.

Configuring Analog Output Triggers

Executing the Trigger