08-28-2010 06:03 PM
I know how to assign channels for dynamic operation, either for generation or acquisition. If I perform an INITIALIZE GENERATION followed by a ASSIGN DYNAMIC CHANNEL, this will set those DIO channels as outputs. If I perform an INITIALIZE ACQUISITION followed by a ASSIGN DYNAMIC CHANNEL, this will program the HSDIO to acquire signals at the DIO channels.
How do I know which DIO channels will be set to outputs and which are inputs? Does the INITIALIZE ACQUISITION followed by ASSIGN DYNAMIC CHANNEL automatically make all of those DIO channels as inputs? How do I program DIO channels as inputs? How do I program DIO channels as outputs?
Thanks,
Roger
08-30-2010 07:13 PM
Dear Roger,
In order to choose which channels you want to use for your generation or acquisition of data you must wire a "channel list" to the"Assign Dynamic Channels" VI. You will find the following example in LabVIEW useful:
Help>>Find Examples>>Hardware Input and Output>>Modular Instruments>>HSDIO>>Dynamic Generation and Acquistion Demo
09-01-2010 10:23 AM
Hey Roger,
I would also like to point out that all of your channels on your 6552 can be assigned as both Generation and Acquisition at the same time. In the HSDIO Help (HTML version) you can see that the Channel Electronics of this device allow you to do this. Then there is the ability to Tristate, or disable the driving of data, any of the Generation channels that you would like, by either writing a digital logic state value of "Z" in your waveform, or by using the Tristate function. When you tristate the line, it is like disconnecting the generation on that line, and allows you to acquire data from whatever is driving data on the other end of the line (from your DUT). So you can either set the channel list for each of your Generation session and your Acquisition session, or you can set all lines to generate and acquire, and then Tristate the channels you don't want to generate on, and ignore the data on the channels that you acquired on that you don't care for its data.
This was just to give you other options in case you were wanting to make a channel bi-directional and how to use it in that way. Definitely check out the examples that show how to use both Generation and Acquisition sessions in the same program.
Regards,
DJ L.
09-02-2010 06:44 AM
DJ,
Thanks for the useful information. One more question. What is the power-up state of the PXI-6552? At power turn-on or after a reset, what is the default state of the DIO?
I will have a DUT connected to the PXI-6552. If I turn power off or reset the PXI-6552, do I have to disconnect the DUT to make sure I won't have two inputs or two outputs connected together when I turn power on again to the PXI-6552?
Is there a way to manage the DIO states at power-up or after a reset?
Thanks,
Roger
09-02-2010 12:16 PM - edited 09-02-2010 12:19 PM
Hey Roger,
The answer to your question about the default power up state can be found in the NI PXI/PCI-6551/6552 Specifications document, on the top of page 4. You should not have to disconnect your dut when you reset the 6552, or if you shut down your computer or PXI controller and restart it. When you find the answer to your question in the Spec doc, let me know if you want to change it to something else. Also, check out the Help doc in my last reply, specifically about Initial and Idle States. Thanks, and have a great day.
Regards,
DJ L.