Continuous acquisition hangs

[Matteo 472]

When I start acquisition with my PCI-MIO 16 X E 10 card (from Measurement Studio for Visual Basic), the system hangs for a few seconds. This is completely unacceptable for my application.

This happens only when the stop condition is set to continuous. And it happens on my Win XP machine, but not on my Win NT 4.0 machine.

On the Support web site of National Instruments I see that others have had similar problems (although their system hangs when stopping, not when starting). The solution that is indicated there is to remove IRQ conflicts, eg by removing USB support.

I tried that solution, and it did not work. The system still hangs. There is not much that one can do about IRQs in Win XP, because they are all assigned to the value 9 b
y Microsoft's ACPI software.

What to do?

Thanks

-Matteo

[RIO-Todd]

Matteo,

What version of NI-DAQ do you have? Make sure that you are using a version compatible with Windows XP. NI-DAQ 6.9.2 and later were built to be supported under XP. If you are using an earlier version of NI-DAQ on the XP machine, I would suggest to uninstall and upgrade to the newest version of NI-DAQ (6.9.3) and see if that eliminates the problem. You can download NI-DAQ 6.9.3 from the link below. I hope this helps.

Current NI-DAQ Versions
http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C128D?opendocument&node=132060_US

Regards,

Todd D.
Applications Engineer
National Instruments

[Matteo 472]

Todd
thanks for your suggestion. I checked the version of NI-daq, and I am already running 6.9.3. What should I try next?
Thanks
-Matteo

[Matteo 472]

Thanks to help from Customer Support at National Instruments, we found the cause for this problem, and a workaround.

The problem can be boiled down to the following: When setting the stop condition to continuous, the number of scans to a high number (eg 840000), and the progress interval to a short number (eg 300), the "start" instruction takes tens of seconds to complete.

This misbehavior must have to do with the NIDAQ 6.9.3 or with Measurement Studio or with Win XP, because it did not appear in NIDAQ 6.1 with ComponentWorks 2.0 in Win NT 4.0.

A very useful visit from a National Instruments representative yielded a simple workaround: do not use continuous acquisition. Now we simply specify a long buffer and we set the stop condition to "no condition", and
everything seems to work fine.