NI 272x Custom Device Feedback

[Jesse_D]

Hi manbir,

It looks very probable that the pharlap OS is crashing because it runs out of RAM:

06/06/2013

22:21:13.959

0

-2147024882

000

Fatal error: Out of memory

CmxsNeoStorage::ValidateDBStructuralIntegrity

The 8186 doesn't have a lot of ram and it possible you are using all the available ram when trying to deploy.

Pharlap loads every driver into memory when it boots. You can free up RAM by removing any drivers not needed. Also, If I remember correctly the console will show you how much free memory you have.

-Can you check whether it is just a memory issue by removing everything but the required 2722 drivers from the PXI and attempting the deploy again?  You might also consider deploying to a PXI with more memory if you have it.

The situation still looks weird to me because your system definition file is so simple. Although crashes because an RT system runs out of RAM happen occasionally it would only happen in the case if almost all of your ram was used anyway.

Do you know how much RAM is in your sysetm?

[StephenB]

Nice catch. Thank you very much Jesse

I should note the look up tables the 272x Driver loads per card are around 15 MB. Also, NIVS uses at least 100 MB of memory. So that starts to add up.

manbir, it appears your target has 246 MB of RAM. Could you upgrade the RAM on that target or find a new target? Or you could try removing drivers you don't need.... but if you add anything more to your system definition you will have trouble.

[ManbirKaur]

I have removed many drivers that are not required and redeployed the project but again it gave same error.

memory status before deploying project

Total memory : 246 Mb

Free memory : 115 Mb

Total Disk Space : 37.2 Gb

Free Disk space : 10.5 Gb

status after the controller went into Safemode(software error)

Total memory : 246 Mb

Free memory : 241 Mb

Total Disk Space : 37.2 Gb

Free Disk space : 10.5 Gb

please find attached the new list of software after removal of some not required drivers as well as MAX report after the error.

[Jesse_D]

Hi Manbir,

The new crash is identical to the old ones. There isn't a simple error message associated with it, I am not sure why. However the detailed report shows a lack of memory, it still looks like the system is running out of memory:

Total system memory:           258408448 bytes

Free memory:                        0 bytes

Largest free block:            0 bytes

Free RTOS heap memory:         167792 bytes

Largest free RTOS heap block:  28672 bytes

Can you create a different custom device, such as the embedded data logger, and try deploying it? Do you have a different RT target you can test on?

[ManbirKaur]

Hi Jesse

We created a LabVIEW code for resistance generation using 272x palettes available in Labview 2011. When we ran that code on 8186, it showed CPU load as 100%.

On adding different custom devices such 2510 FIU, the code gets deployed successfully.

But I need to reinstall the veristand and labview again in my controller to deploy any code successfully in labview, after every crash due to 2722 custom device.

I don't have different RT target to test on. 

[Tom_@_RTC]

Hi,

I have the PXI-272X Custom driver installed on a PXI system running Veristand 2012.

I am using the card with all the channels connected together (CH0 to CH4) in series.

All works dandy, except when I want a resistance that is less than 1 Ohm.

The driver seems to limit the output to 1.02 Ohms per channel (5.1 Ohms total).

There does not seem any logical reason why a card that has a resolution of 0.25 Ohms should struggle reaching that ohmage, afterall it is just turning on relays.

Can you please advise what to do to get to lower ohmage.

Also why is there a limitation to 1 ohm per channel?

Cheers

[StephenB]

Hi Tom,

The 2722 card, which I think you're using, specifies a minimum resistance per channel as typically 2 Ohms.

http://www.ni.com/pdf/manuals/375813a.pdf

Sorry that I cannot fix this, as it is expected behavior.

[Tom_@_RTC]

Hi Stephen,

Thanks for a quick reply.

Ah that would be the cause of my problem then! Ill have to get some parallel resistors on the go to get to the levels that I require then.

Thanks very much

[Keunmo]

Dear Jesse,

I have been using two PXIe-2727s and recently experienced a few incidents that some channels failed to update resistance values. My tests with the PXI chassis are a week long and, at some point, some channels in PXIe-2727s stop updating the resistance values while the model in the PXI chassis dynamically changes the values. I realized that, under the custom device, there are Error Code and Loop Duration. Error Code was always 0. I looked at Loop Duration and the PXIe-2727 with 8 channels in use almost always overruns (I set the default update rate 10 Hz and the loop duration most of time is more than 100 ms). Would that be the root cause? I am rerunning my test with 2 Hz update rate now, but would like to get your thought at the same time. My controller is PXIe-8135 with DAQmx9.6.2. I am using VeriStand 2012. Unfortunately, I do not remember what version of custom device I am using, but I am using whatever available in Spring 2013. 

Thanks in advance,

Keunmo

[StephenB]

Hi Keunmo,

I'm sorry to hear that. The long loop duration is unexpected. Could you try using the latest version of the custom device?

Thank you