PCI Schnittstelle der NI PCI-5152 / PCI interface of the NI PCI-5152

[luase]

Um welche PCI Schnittstelle handelt es sich bei der PCI-5152 genau. D.h. mich interessiert die Taktfrequenz (33, 66, 100 oder 133 MHz) und dann noch die PCI Busbreite (32 oder 64 Bit).

Mir gehts um die maximal mögliche Datenrate, die ich mit der, beim PCI-5152 Digitizer verwendeten, PCI Schnittstelle erziehlen kann.

I need to know what kind of PCI interface the PCI-5152 uses in order to calculate the max. datarate. I need to know the clockrate of the used pci interface (33,66,100 or 133MHz) and whether it is a 32 Bit or a 64 Bit PCI Interface

Message Edited by luase on 09-06-2007 08:39 AM

[psisterhen]

The device supports a 32-bit, 33 MHz interface.  So the theoretical maximum data rate is 132 MB/s.  This is dependent on various overhead and what other traffic is happening on the bus, of course. 

With proper programming using the NI-Scope driver, you should be able to maintain around 100 MB/s.

[luase]

Thank you very much for your fast reply. That helps me a lot.

Could you give me some hints what proper programming means, because I’ve got very tough requirements using the PCI-5152.

I have to sample at least 150.000.000 pulses.

The pulse frequency is 1MHz and the pulse width is 50ns, that means 50ns ON-Time and 950ns OFF-Time. I think I have to use continuous acquisition and the multirecord mode. In order to minimize the amount of sampled data I want to sample every second pulse because the rearm time of the digitizer is just 1µs and I want to take 100 samples of the 50 ns pulse. I thought of taking 25 samples before the pulse (OFF Time) then 50 samples of the actual pulse (ON-TIME) and in the end 25 samples after the pulse (OFF Time). This I want to realize with 25 pre-trigger-samples and 75 post-trigger-samples. The Trigger is an extern 1MHz square wave that is synchronous to the pulse I want to sample

So I would get a data rate of 50MB/s (100 Samples/Byte within 2µs = 50MB/s) and I get 500.000 pulses per second. Since I need at least 150.000.000 pulses each sampled with 100 values I get finally a data amount of 15 GB and have to sample over a time period of 300 seconds.

As further information: I have also 2 another NI measurements cards in my pc (also PCI Slots). One DIO card and one AIO card. These cards will not be used while sampling the data whit the PCI 5152.

And my question is: Is it possible to handle this problem with this huge amount of data and could you give me some advice how I could handle it.

Thank you very much for your help.

Kind regards

Viktor

[Paul_C.]

Hi Viktor,

I would recommend taking a look at our digitizer examples for help with "proper programming" procedures (In LabVIEW, go to Help » Find Examples » Hardware Input and Output » Modular Instruments » Ni-Scope » General » niScope EX Save to File.vi).  I would also highly recommend going to our streaming webpage found here and reading the developer zone document about streaming found here.  From the article, you can see that often the limitation in streaming to disk is the hard drive speeds and possibly the PCI bus speed if your sharing the bandwidth between PCI cards.  There are also some great streaming examples for digitizers found here.  I double checked all your numbers and they appear correct.  I just want to make sure that you know that the rearm time is only 1us with the Time-to-Digital Converter (TDC) turned off.  The way it looks you will need to sample at 1GS/s (1ns resolution for 50 samples in the 50ns window) to achieve the samples you require.  With a rearm time of 1us, you will miss every other trigger as you stated and this should work fine.  I think the reason that psisterhen expressed concern is because of the large number of variable that must be considered when streaming at such a fast rate.  The program you use will have to be programmed very efficiently and with good technique to accomplish the rates you're looking for.

My primary concern would be that your data transfer rate to hard disk would meet the 50MB/s speeds.  You will see that the example uses a Addonics eSATA 4-drive RAID array to reach their 110MB/s rates.  I would also recommend taking a look at the producer/consumer example.  If you need more information about this type of programming, I would highly recommend reading the document found here.  This allows you to keep your data acquisition loop separate from your write to file loop.

I hope this helps,
Paul C.

Message Edited by Paul C. on 09-13-2007 06:36 PM

[luase]

Hello Paul,

thank you very much for your help. I will have a look to the articles you gave me and do some tests with the Digitizer.

So I hope I will handle it with your advices.

Thanks a lot.

Kind regards

Viktor