SignalExpress runs excruciatingly slow

[dclampp]

Hello:

I'm new to using LabView's SignalExpress.  I'm trying to run it on a windows-based, NI PXI-8196 controller in an 8-slot chassis. My current application involves generating a simple linear frequency sweep with a function generator, running it through a UUT, collecting its output with a scope, and plotting the dB magnitude return (using devices located in the chassis). 

Unfortunately, every single little thing I do with the program interface seems to take 5-15 seconds to process.  Switching tabs in configuration windows for generation/acquisition/etc steps, or changing values, creating or deleting new steps in the line, even changing the ranges on the graphs causes my system to bog down and requires 5-15 seconds of patience to get control of the program back with a 50/50 chance of my input change being acknowledged.  Even doing things like creating a simulated signal that does not involve PXI peripherals takes an extremely long time to open/configure/click. 

I'm curious if this is just how slowly SignalExpress naturally runs because of the various parameters/configurations it needs to change over the bus, etc.  I'm not running any other programs so, as far as I can tell, I'm not sucking processing power elsewhere.  Does SignalExpress intrinsically require this much time per user-input to update all that it must, or could my system be incorrectly configured or something?  It gets extremely frustrating when it takes up to 15 seconds to input a change in the sampling frequency from 1M to 10M. 

Thanks in advance for your help/advice/insight!

[Christophe R]

Hi,

Reconfiguring the hardware steps shouldn't take so much time. You mentioned that your application is generating a linear frequency sweep with the function generator, so I assume that you are using the sweep step. Is this correct? Are you trying to reconfigure the steps during the execution of the sweep? I believe that SignalExpress will wait until the sweep has finished executing all its iterations before applying the new configuration. What happens if you reconfigure the steps while SignalExpress is idle. Does is also take that much time?

If it does, can you check the CPU usage associated with SignalExpress? Can you also attach your project so I can take a look at it?

[dclampp]

I don't believe the problem lies in the program itself; i merely modified the example sweep program to actually FGEN output the signal (and acquire it via NI-SCOPE), but I've attached it anyway.  The significant lag I'm experiencing begins from the moment I open SignalExpress itself and continues regardless of what operation I'm trying to do (or what project I'm running).  While watching my process time in the Task Manager, every single mouse click takes 99% of CPU time for 3-10 seconds. 

I haven't tried modifying the steps during the sweep operation.  All these issues arise from working with it when the system is idle.  Given that the project isn't running, any type of configuration modification or attempts at navigation in the SignalExpress 'front panel' results in the aforementioned 3-15 second processing delay, in which SignalExpress takes 99% CPU time and the Task Manager indicates that the program is "Not Responding."   The overall net effect is I feel like I'm trying to run the program/interface on a legacy pentium II, 333MHz system, slow slow slow.  Something as simple from changing from the "Triggers" tab to the "Execution Control" tab in the FGEN configuration menu (while the project, chassis, etc is idle) is taking 5+ seconds of 99% processor time.  The result is the same when I try to change a numerical value, say sampling frequency (even just getting the cursor to appear in the input field), takes 5+ seconds. 

I'm hesitant to think that this lag is hardware dependent.  When I am doing operations that do not require an interface/configuration of a DAQ or FGEN (for example, configuring a formula step), the delay is the same.  I would think the PXI-8196 has sufficient processing power to do all this quite quickly, so I'm stumped.

That said, all my drivers (DAQmx, FGEN, NI-Scope, etc) are current.  In my chassis I have a PXI-7813R (RIO), PXI-5421 (FGEN), PXI-6115 (S-series DAQ), PXI-5922 (flex-res digitizer), and a PXI-6250 (m-series DAQ). 

Thanks again!

[Christophe R]

If you restart the controller, and just launch SignalExpress, what is the CPU and memory usage? Does the problem start occuring as soon as you drop any step? If you look at the list of processes in the task manager, do you see any other processes that also take a lot of CPU? What is the list of NI Software installed on the controller?

This sounds like a tricky problem. If you are ok with it, I can ask your email address to the forum administrator to contact you directly, or you can contact the National Instruments technical support and mention this discussion thread.

[Minh T.]

Good afternoon dclampp,

Thanks for contacting National Instruments with your issue, we'll try our best to get your issue resolved as quickly and efficiently as possible.

Which version of SignalExpress are you running?  You can check by going to Measurement and Automation Explorer and expanding the Software tab and checking  the version column of the Attributes window.  Also is it an evaluation copy? 

I just downloaded your project and had no issues modifying the attributes and properties and navigating between tabs and windows.  I'm running SignalExpress 1.1. 

It sounds like you may have a corrupted install of SignalExpress.  It's suggested that all of your drivers be installed first (i.e. NI-Scope, NI-DAQmx etc), then the actual hardware and then SignalExpress.  Please try repairing or uninstalling/reinstalling SignalExpress when you get the chance to see if this might resolve your issue.

Please let me know the results of this and let me know if you have any further questions.

Sincerely,
Minh Tran
Applications Engineering
National Instruments

[dclampp]

Hello restat, Minh: 

restat:  With the computer freshly booted and no other applications running, the only task consuming processor time is SignalExpress, which, when active, consumes 99% of CPU time.  It also uses 50MB of ram initially and creeps upward; before it gets unbearably slow, I've seen it at 180MB.  Software wise, I have all appropriate drivers for the hardware mentioned above and Labview 7.1.

Minh:  I am running SignalExpress 1.1.1.   It is not an evaluation copy.   Per your suggestion, I removed and reinstalled the program.  Behavior remains the same.

While playing with the system over the weekend, I noticed that the performance was dependent on a) the resolution of my monitor, and b) the size of the window (maximized v. smaller).  I'm using a Dell flat panel, widescreen ultrasharp 20" monitor (analog input), whose drivers I had to install to the PXI windows-based controller.  I am thinking now that the video card on the controller cannot drive the resolution I was initially at: when at full resolution 1680x1050, the image looked 'smeared' in places and normal in others; other resolution selections would look blurry or overly sharpened.  The program ran at its worst in the case of highest resolution.  At 1024x768, SignalExpress would run quicker while maximized, and even quicker still when only occupying half of the screen.  Perhaps the PXI video card does not have the capability to drive the monitor efficiently, and this difficulty is compounded by SignalExpress' significant graphics load?

I've never used a flat panel widescreen monitor with a PXI computer; does anyone have experience with this and ran into this sort of problem?

Thanks for your help!

[dclampp]

(see above)

[Minh T.]

Thanks for the reply dclampp,

There appears to definitely be a correlation between the amount of video resources required and the performance of your system.

There is a knowledge base which talks about this:

http://digital.ni.com/public.nsf/websearch/BB919BECF3BF81D98625708200546766?OpenDocument

Have you run any other programs besides SignalExpress to see if this specific to that program or some general performance issue with the 8196?  Do you have the 8196RT, if so if you're running the RTX OS then it's possible a background RT program is using up resources as well.

The 8196 ships with 512 MBs ram but can handle as much as 2 GBs, so it's well within what SignalExpress is using, however it is suspicious. 

I cannot see why the 8196 would have any more trouble using a flat panel screen as opposed to a standard CRT screen for equivalent resolutions, but I will definitely ask around about this issue.

Sincerely,
Minh Tran

Applications Enginering
National Instruments