Getting DAQmx overload property

[d1sturbanc3]

I'm trying to get when my DAQ is in a overload state. However, I keep getting this error.

Error -200983 occurred at Property Node DAQmx Read (arg 1) in collect data.vi->Front Planel.vi

Possible reason(s):

Measurements: You only can get the specified property while the task is reserved, committed or while the task is running.

Reserve, commit or start the task prior to getting the property.

Property: OverloadedChansExist

Task Name: _unnamedTask<7>

I've attached what DAQ setup looks like.


Some background of what I'm doing.
Basically I have a trigger attached to my DAQ. I want to the DAQ to go off everytime the triggers goes off. The trigger is synced to a GPS which is providing a 1 sec pulse. I want my DAQ to collect for one sec, and wait for the 2nd pulse and repeat.

Ah crap I put this in the wrong forum. oh well.


Message Edited by d1sturbanc3 on 04-01-2008 03:09 PM

[Chris_K_]

Hi d1sturban

Thank you for using our discussion forums.

It is difficult to tell why you are getting this error without knowing some additional information.  What DAQ device are you using?  Ensure that this particular property is supported by this card.  This information can be found in the DAQmx help file.

In the screen shot you posted it is not possible to tell if you have started the task.  The error tells us that this property can only be read while the task is running.  On the same not from you description, do you get this error on the first call to this property node or do you get is on the second call.  You can check this using the highlight execute or breakpoints. 

Let me know how these steps turn out and if you are still seeing this error I can continue to troubleshoot the issue.

Chris_K

[d1sturbanc3]

Thanks for the reply. This is actually a follow up to this. http://forums.ni.com/ni/board/message?board.id=250&message.id=37142&query.id=28957#M37142 I couldn't find post yesterday. Maybe I should continue from that.

I'm using a PC NI PCI 4662. It supports overload based on the spec. I think I know what's happening, but I don't know how to fix it. It's trying to grab the property when the task is in a stopped state. I force a stop after my 1 read and wait for a trigger. It's trying to access the property then. How do I get the property when it's running?

I have started the task. When I take the property node out, it works beatifully except I don't know when it's overload.

Here is what I have on my outside.



I don't want to post VI, b/c it's too complex connected to other things.

Another note is that I found something similar done in an example.
\Analog In\Measure Acceleration.llb\Cont Acq Accel Samples-Int Clk-Analog Start.vi Is the example.

The difference between my setup and that is that I'm reading in Voltage,  finite sample, digital edge, and I have a stop in my while loop.


Message Edited by d1sturbanc3 on 04-03-2008 01:15 PM

Message Edited by d1sturbanc3 on 04-03-2008 01:20 PM

[Chris_K_]

Hi d1sturban

You are correct, the 4462 does support this feature, and as you mentioned the error tells us that the task is stopped when you are trying to read this property. 

It sounds like there is quite a bit going on in your application so it might be difficult to determine exactly how to get away from this error.  I am going to suggest trying a simple analog input example, no sample clocks or triggers, and place this property node in the example and see if you can read it.  Then start building more complexity into the example.  For instance start with a continuous acquisition, then change it to a finite acquisition such as you already have.  Then start adding other aspects such as your triggers.  This will allow you to find exactly what part of your program is causing this to happen. 

Another approach to this would be to simplify your existing however this may be more difficult. 

Chris_K