Error running example VIs on RT target (lvdaq.dll)

[AndyJD]

Hi all,
I am desperately trying to update multiple Analog outputs on a PC based RT target (LabVIEW 7.1 RT).
I have tried to set up an array with 2 values from different sources to be output using the AO Write VI.

All of the examples I have found give me the following error....
"LabVIEW: Failed to load shared library lvdaq.dll on RT target device."

What I am trying to do I have done many times in LabWindows. Using 2 separate DAQ Assistant VIs means I only get an update on one of my AO channels.

I can read a single analog I/P, and produce a single analog O/P using DAQ Assistant VIs (under LabVIEW RT).
Is there an example of updating multiple DC output levels continuously in RT please?

Thanks,
Andy

[Stuart_R]

Does this message appear as soon as the VI starts running?

Sounds like the code is having trouble finding the DAQ driver, which version have you installed on the target? Can you clarify your 1st post. Are you able to use the DAQ assistant without problems, its just that you get the error when trying to run these examples?

It might be worth verifying the driver is on the target. I would also be tempted to remove the driver if it is there and then re-install, just in case.

[AndyJD]

The error was produced just as the VIs started to be downloaded to the target.
I rang NI support and found the reason for this.

All of the documentation I have been reading states that DAQmx should be used for better performance etc.
I had LabVIEW RT and DAQmx downloaded onto the RT target.

I was told I need to also install traditional DAQ as well (I assumed that DAQmx supported legacy devices).
Anyway, I get a different error when I run any of the examples now....

"Error -10401 occurred at AO Group Config" then lists possible reasons, e.g. the driver does not support the device.

I am using DAQ Assistant VIs for each of my Analog outputs now, but I have to set the generation mode to '1 Sample (On Demand)', which is not the best setting I have read. This works OK but I have also read that Express VIs, including the DAQ Assistant are not good for performance.

I am wondering if my problems are due to using the simulation module, all my code is within a simulation loop.

[Stuart_R]

I have no experience with the simulation module but I'm guessing that this could be part of the problem. Are you saying that your trying to download code to the target that includes simulation module code? Why are you using this?

With regards to the express vi efficiency; express vi's use lower level functions to implement the code, but because the express vi's can be configured to behave in a variety of ways, some of the code will become redundant and may not be structured in the most efficient way in order for them to be configured for the various options. If you right click on an express vi and open the front panel, you will see the lower level code implemented in subVI's etc. There is nothing stopping you from modifying this code and improving upon it.

What hardware are you using?

[AndyJD]

Hi,

I am using the simulation module to simulate real world physics of actuator movement and feedback. Various analog servo drives from the unit under test send a demand for a position. I have to model these real actuator's position using Simulink type models (first order lag etc.) which sends the position back in the form of an analog voltage (closed loop system).

My RT target is an Intel based PC. This has 2 NI DAQ devices...a 6723 analog output board, and a 6259 M analog input board.

Thanks for all your help by the way.

I am currently trying to understand how to run 3 separate VIs (applications) on my RT target, each performing a simulation of a separate actuator (with their own analog input and outputs). If I run more than one then the system seems to lock. I have the execution trace toolkit so am trying to configure that.

cheers,
Andy