Problem in continuous acquisition (Traditional DAQ)

[Vijay Jayabalan]

Hai all

Thanks in advance.

Processor performance reaches 100 percent.

Testing DAQ6052E card in MAX for continuous mode of acquisition (Traditional DAQ not on DAQmx) causes processor to reach 100 percent

During testing versions are

MAX-3.1.1

NI DAQ-7.4.1f4, 7.4, 7.2 (All these versions leads the same result)

PC-2.4GHz and in PXI-8186-1.7688GHz

RAM-512MB

The same behaviour i observed when i tested 6034E DAQ card under the same above mentioned environment with the same versions.

The same behaviour i observed when i used a LV example program too (Buffered continuous acquisition).

But this behaviour is not present when i tested the DAQ card in DAQmx for continuous mode of acquisition.

See the attached observation in PXI-8186 controller with 1.7GHz processor with 512MB RAM.

[AlanArmstead]

Hello,

This is a known issue with Traditional (Legacy) NI-DAQ.  When an AI Read is waiting for samples (i.e. you ask for 1000 samples, and there are only 500 available) it will spin on the processor, causing 100% CPU usage.

This has been addressed in NI-DAQmx, as you have noticed.  Here is a good KnowldegeBase describing NI-DAQmx and CPU usage:  Default CPU Usage With NI-DAQmx Version 7.4

So, the obvious suggestion is, use NI-DAQmx.  If you are curious about compatibilities with NI-DAQmx, this link shows what boards are supported by which driver:  Data Acquisition (DAQ) Installation/Configuration Troubleshooter

-Alan A.