National Instruments IEEE 1394 Manual De Usuario

Figure 3-2.  Partial Image Size Format (Format 7)

The IIDC 1.31 specification provides several external triggering modes for 
IEEE 1394 cameras. A IEEE 1394 camera may support one or more of the 
triggering modes. Refer to your camera documentation to find out which 
standard modes are implemented.

All of the NI-IMAQ for IEEE 1394 Cameras ADEs have a Trigger 
Configure function. The Trigger Configure function has the following input 
parameters:

•

Polarity—Specifies when the trigger input is active. A value of TRUE 
indicates that the trigger is considered active when the value is high. 
The default value depends on the vendor implementation of the 
IEEE 1394 camera.

•

Timeout—Maps to the acquisition timeout attribute. Use this 
parameter to specify the amount of time to wait for a trigger before 
issuing a timeout error. Specify a timeout duration that is at least as 
long as the cycle time of the slowest expected frame rate.

•

Mode—Specifies one of the trigger modes described in the following 
sections.

•

Optional—Certain trigger modes require an additional parameter. 
Refer to the following sections to see if the optional parameter is 
required.

Full Image Size

Unit Width

Unit

Height

User-Defined

Region

Acquired Sub-Image