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pcie-6537 bidirectional


We are considering use of multiple PCIe-6537 boards for high channel count (256) bi-directional digital stimulus/response, with four boards per host rackmount PC featuring newer PCIe motherboard (two rackmount PCs total).

Few years ago we had challenges doing similar with PCI-6541. We quickly discovered this board could not dynamically change direction. Also, we found minimal support for using Visual Basic alone without LV or Measurement Studio. Question is, can the PCIe-6537 support bi-directional data flow with quick turnaround, for example with all channels switching direction in 10 or less clock cycles (250 nsec)? Also, is there good support for use of Visual Basic (2008 Express Edition) to develop straightforward digital stimulus followed by digital acquisition application?


Thx in advance


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Here is the list of on-the-fly bidirectional digital boards that we offer.


NI PCI/PXI-6551 (Up to 50 MHz - 20 ch) - NI PXI-6551 / NI PCI-6551

NI PCI/PXI-6552 (Up to 100 MHz - 20 ch) - NI PXI-6552 / NI PCI-6552

NI PXIe-6547 (Up to 100 MHz - on 24 ch)- NI PXIe-6547

NI PXIe-6548 (Up to 200 MHz - on 24 ch) - NI PXIe-6548


The PXIe-6537 is not capable of on the fly direction control.  The direction is controlled in software.  However, on the 6548 for example you can output -> tristate channels on a per cycle basis (5 ns at 200 MHz).


If you are looking for PCI boards only, I would recommend the 6551 or the 6552.  The 6547 and 6548 are PXI express based only, not PCI or PCIe.  If you want to use the 6547/48 you would need a PXI Express chassis.


LabWindows/CVI and ANSI are officially supported with the NI-HSDIO driver.  There are plenty of text based examples showing how you can use these boards for bidirectional capabilities.  These same examples can be used for Visual Basic as well.


Take a look at this article that shows you how to use the NI-HSDIO driver with Visual Basic.


Hope that helps.

Raajit L
National Instruments
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Hi Raajit,


We have NI PCI-6551 (50MHz,20ch). Can we use it with DAQmx to generate waveforms in a DAQ Assist VI?  What driver we need? I have never used it before. Thanks


best regards,


David Day


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Hi David,


The NI 6551 uses the NI-HSDIO driver that you can download from here (latest driver is 1.7).


This driver has Express VIs (search for NI HSDIO Express Generation in the LabVIEW functions palette) that you can use to generate/acquire your waveforms, similar to the DAQ Assistant.  There are many more features in this driver specific to digital testing that do not exist in the DAQmx driver, such as hardware compare and per cycle state control.  I would recommend using one of the example programs that you can find in the LabVIEW environment by clicking on Help >> Find Examples >> Hardware >> Modular Instruments >> NI-HSDIO >> Dynamic Generation >> Dynamic  


If you are looking to just generate simple waveforms, I recommend looking at the Dynamic as a starting point.  What are you using the NI 6551 for?  Will you be using the hardware compare or bidirectional features?


Hope that helps.  Let me know if you have any further questions.

Raajit L
National Instruments
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