Error -200278 occurred at DAQmx Read

[cobayatron]

Hi,

Following an example developed by a super helpful NI support engineer. I made a very simple acquisition routine with a certain level of synchronization between the tasks (Attached) to be used in a PXI system between strain gauges modules (4330), voltage module (6341) and an independent SCXI1000 chasis. The routine seems to work fine until a certain moment when a very strange problem pops up (-200278). It's always the voltage task which generates the error.

Any suggestions?

[JÞB · Accepted solution]

The voltage task is set to acquire finite samples.  You want "Continuous samples" I think.

[Kevin_Price]

That error indicates that you have a task configured for Finite Sampling and after several loop iterations, you're eventually asking to DAQmx Read more samples than you configured the task to acquire.

Judging by the way the Read loop is structured, you probably should wire in the value "Continuous Samples" to the 'sample mode' input of all your DAQmx Timing calls. ( When left unwired, the default value is "Finite Samples".)

While you're at it, you should make sure that the strain task starts last so the other tasks are already started and waiting for its triggering signal.  Also, your 'error out' should probably move to the end of the task chain, though I understand you may have only placed it earlier for temporary troubleshooting.

-Kevin P

P.S. There I go again.  Opened the thread in a new tab, came back to it later without refreshing, then posted a response only to find that someone else already answered it in the meantime.

[cobayatron]

Ups! I could have been looking for years and I wouldn't have seen that! Thanks a million!