What is a "reasonable" RAM size for my system?

[AMP12]

I'm getting an error (Error 200020) for on board device memory overflow.  It sound to me that I may not have enought RAM on my system to support this appilcation.  I'm running Labview 7.1 with an E series DAQ and an SCC2345 carrier.  My computer has approx. 14G harddrive and 256M RAM.  What would a "reasonable" amount of RAM be to use on this system?

I know NI has some minimum requirements that allow the system to work, but there is usually some higher lever needed to make a system work at an effiecent level for most other software.

Is there any rule of thumb for RAM vs. hard drive space or RAM vs. processor speed?  I recall from my training class that the performance trade off was memory for speed or something like that.  I don't remember exactly which it was.  If anyone can shed some light on all of these questions, I'd appreciate it.

[Tom_W_[DE]]

Hi Clampy-

The 200020 error generally refers to memory on board with the NI-DAQ device itself.  Which specific device are you running?  Which version of the NI-DAQmx driver?

I would first verify that you are up-to-date with NI-DAQmx 7.5.  I would also attempt to use this board in other computers to make sure that there is not a specific conflict with this system.

To address your questions about memory, the NI-DAQmx 7.5 ReadMe indicates that your 256 MB is the minimum recommended RAM for the development computer.  In general RAM and processor speed determine the overall apparent performance of your system and an increase in RAM will generally show a more noticable increase in performance.  I am running a 3.2GHz Pentium 4 with 1GB of RAM and seeing good results, but I know this is not an option for everyone.  However, if you have the option to increase your RAM and CPU speed I would strongly recommend it.

Please let us know if you are not able to see better results.

Thanks-

[AMP12]

I just upgraded the MAX driver to 7.5.  Labview is currently 7.1.  I tried running the same labview programs with recreated MAX tasks on another computer with 512M of RAM with the same results.  I am using a 6024E with the 256M system and a 6036E with the 512M system.

I switch configurations to a continuous sampling option and seem to be avoiding the error that I had originally gotten with that config.  I don't recall the error.  I have recently upgraded to the 7.5 driver to avoid a 100% CPU usage problem, and now some of my applications have other problems, this is one of them.

[Tom_W_[DE]]

Hi Clampy-

I would suggest taking a look at one of the LabVIEW shipping examples for continuous acquisition to verify if the problem might be in your task creation and setup.

You can view these examples in LabVIEW by accessing the NI Example Finder (Help>>Find Examples) and browsing to Hardware Input and Output>>DAQmx>>Analog Measurements>>Voltage.  A great example to try is "Cont Acq&Graph Voltage-Int Clk.vi"

When working with lengthy acquisitions it is important to set the sampling parameters appropriately to avoid on board memory overflows.  This generally means that the "samples to read" input to DAQmx Read should be roughly 10%-50% of the sampling rate supplied to the DAQmx Timing VI.  This ensures that you are reading data from the on board memory fast enough to prevent buffer overrun conditions.

Thanks-