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Writing to Camera Registers with IMAQdx Takes Longer than with Native Camera Driver

Primary Software: Driver Software>>NI-IMAQdx
Primary Software Version: N/A
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem:
I am trying to repeatedly write to a register on a Firewire camera with the IMAQdx driver and notice that it takes a lot longer than when I write to the registers with a driver specifically built for the camera. This is especially noticed when trying to write to a "trigger" register to perform a software trigger at high speeds. Can I improve this write speed?

Solution:
The problem is that older Firewire cameras are known for "Locking Up" if feeling too much stress from consecutive writes to the registers. So to make IMAQdx compatible with older Firewire cameras we have put in an artificial delay between each "Write Register" function call of 5ms. Newer Firewire cameras can handle this stress though so do not need this delay.

This delay is actually set in the Windows Registry and can be changed to a value of "0" so there is no delay. You can either apply the attached file "niimaqdx_no_register_delay.reg" which will automatically update the correct registry or change it manually in the windows registry.

Manual Change:
  1. Go to Start » Run and type regedit
  2. Navigate the registry to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ niimaqdxk\Parameters
  3. Right Click on Async Transfer Delay and choose Modify
  4. Change the Value to 0
  5. Restart Windows for the changes to take effect

This is also detailed in the NI IMAQdx User Manual on Page: A-5.

Related Links: Product Manuals: NI-IMAQdx User Manual (Feburary 2007)


Attachments:


niimaqdx_no_register_delay.reg - niimaqdx_no_register_delay.reg

Report Date: 05/04/2007
Last Updated: 05/11/2007
Document ID: 493CQGP6

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