Academic Company Events NI Developer Zone Support Solutions Products & Services Contact NI MyNI
This Document is not yet Rated  Rate this Document

Acquisition Step in VBAI Always Fails When Using IMAQdx

Primary Software: Vision Builder for Automated Inspection
Primary Software Version: N/A
Primary Software Fixed Version: N/A
Secondary Software: Driver Software>>NI-IMAQ for IEEE-1394

Problem:

I am acquiring from an IEEE 1394 Firewire camera in Vision Builder for Automated Inspection (VBAI) using IMAQdx.  I can acquire and see the image fine when I am configuring the acquisition step but as soon as I select OK the step fails and no image is acquired.  See the following picture:

I can acquire completely fine in Measurement and Automation Explorer (MAX) and Vision Assistant just not after selecting OK for the acquisition step in VBAI.



Solution:

This most likely occurs when you are acquiring from a camera that did not follow the DCAM specifications for all of its attributes.  If you click through all the available attributes for the camera you will most likely find an attribute that contains a value of: "0".  This is considered to be an invalid value.  If you change this value to anything other than "0" you should then be able to select OK and the acquisition step will not fail. 

This occurs because IMAQdx generates the attributes dynamically from an XML file that is created from the camera.  If the proper DCAM specifications are not followed by the camera manufacturer then the default values for some of the attributes populate with this invalid value.  The key is that when you select OK in VBAI it actually goes through every attribute that is available and tries to set the associated values.  So if an attribute's default value is not generated correctly from the camera, VBAI will try to set the attribute to "Invalid" on the camera, which generates an error.  So simply changing any invalid attribute value to a known value will fix this problem. 

The reason this does not occur in MAX or Vision Assistant is because when you select Grab or Snap it uses the attributes already configured on the camera.  Attributes are then only changed on the camera individually when you change them in MAX. 



Related Links:

Attachments:





Report Date: 06/05/2007
Last Updated: 08/04/2007
Document ID: 4A4MIAP6

Your Feedback! poor Poor  |  Excellent excellent   Yes No
 Document Quality? 
 Answered Your Question? 
  1 2 3 4 5
Please Contact NI for all product and support inquiries.submit