653x freezes computer

[OZI]

Hi

we have a problem with a freezing computer. We use a 6534 high speed digital input card and we input data with 20MHz at 32 Bit. The application is running 24/7.

The problem is two or three times a day the computer freezes, we don't know why. The same application is running on other computers without any problems. We expect a jitter on the clock and made tests with a higher clock rate. The maximum what the 6534 can work with is 20MHz. We made a test and at a clock rate of 33MHz the computer freezes.

Can a jitter also freeze the computer?

Why does a NI card freeze the computer?

Does anyone know a solution

We use:

- windows XP

- NIDAQ 7.1

- PXI-6534

- CVI

- Pentium Dual Core Computer with 2.5GHz

Thanks

 Oliver

[CarstenS]

Hi Oliver,

a freezing PC could be due to memory problems. Do you have any build array functions in your code?

Can you check the size of the memory when the PC freezes? Therefor open the taskmanager so you can see the memorysize even when it's frozen

Kind regards

Carsten

NI Germany

[OZI]

Hi Carsten,

we have two big arrays were we store the datas from the measurement. That means we start a DIG_Block_In and the pointer of the measurement goes to a very big array. To be sure that there is no memory problem we made the memory array five times bigger than the maximum size.

When the computer freezes it is not possible to open the task manager. Nothing is possible any more, but switch off and on.

We made a test in the lab with a second system and we found out that we can bring the computer to freeze when we increase the frequency of the clock up to 33MHz. The we have the same problem. But at the customer we have only 20MHz

Is there any log file when there is a break down?

Thanks

Olive

[CarstenS]

Hi Oliver,

you said that you have made the memory array five times bigger then needed, does it mean that you're initializing an array before you're storing your data in it? Are you using the replace array subset fuction?

Can you try opening  the task manager before you start your acquisition so you should be able to view the memory status at the freeze

Kind regards

Carsten

NI Germany

[OZI]

Hello Carsten,

generally we work in that way that we initialize a memory array for each measurement when we start the software and this memory is used until the software will be closed. So we created a five times bigger memory now and we always overwrite the arrays.

A current test today with the task manager is possible because our customer shut down the system this morning because it freezed four times in two hours. (Normally we have two-three times a day)

Oliver

[CarstenS]

Hi Oliver,

please let me know your testresults if you got them.

Do you have the possibility to post your code so I can have a look on it?

Regards

Carsten

[OZI]

Hi Carsten,

in the moment it is not possible to make test because the customer deactivated the system.

The main question is why can we freeze the computer by increasing the frequency of the 6534 over 20MHz and how can we avoid this.

Oliver

[ebalci]

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OZI wrote:

...

The main question is why can we freeze the computer by increasing the frequency of the 6534 over 20MHz ...

---

I did not think it throughly and you already mentioned that the max is 20Mhz, so can it be because of this maximum clock rate limit (as shown on the product web page)?

What happens if you lower the freq a little, does the problem disappear completely?

 

Message Edited by ebalci on 19-01-2010 01:22 PM

[OZI]

Hello Erin,

of course we exceed the maximum to find out what happens! What shall we do else? The computer freezes several times a day, we get no log file, we can not call the task manager. Nothing is working anymore.

The questions is why can only one card freeze a complete computer only because we exceed the maximum??? What happens is a typical DMA problem and we think that the NI card corrupts the PCI-bus. Now we need a solution how to avoid that the computer freezes.

We do 200.000 measurements a day each at 20MHz. And two-three times a day the computer freezes. The time base of 20MHz is constant, but we expect that perhaps of a EMC problem the card gets a higher frequency for a short time.For this reason we test what happens if we exceed that maximum.

Now the question is how can we avoid the freezing

Oliver

[ebalci]

You said, "Nothing is working anymore". Do you mean you cannot even operate at a lower frequency?

In first post, you mentioned about a working system with the same configuration.

Did you try switching their cards to see if you can move the problem to the other PC along with the card or not?

Maybe it is your mainboard not being able to handle the speed anymore? Just a guess...