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Device Terminals on an Unlabled Connector Block

Hardware: Multifunction DAQ (MIO)>>Connector Blocks>>BNC-2111, Multifunction DAQ (MIO)>>M Series

Problem:
I have a BNC-2111 with a PCI-6251 DAQ card. I would like to count the pulses of an external signal but PFI3 and PFI8 are not accessible. How do I access signals that do not appear to be available on the connector block such as Counter 0’s Source pin (CTR 0 SRC), which is by default PFI8?


Solution:
Many connector blocks such as the BNC-2111 for example, are populated with several external connectors labeled by the names of the inputs and/or outputs that are typically found on the pinout diagrams of a particular M-series device. However, upon closer examination, it is apparent that the number of connectors does not always necessarily match the number of I/O terminals on the device. An example of this is presented in the following diagrams displaying the available signals of the BNC-2111 and the pinout of a PCI-6251:

 
 
 
It is apparent that, CTR 0 SRC (PFI3) and CTR 8 SCR (PFI8) are not accessible. Access to these signals may be established by configuring one of the available PFI (Programmable Function Interface) lines, say PFI0, to be routed internally to the Counter 0 Source. It is important to remember that each of these terminals can be individually configured. As an input, each PFI terminal can be used to supply an external source for AI, AO, DI, and DO timing signals or counter/timer inputs. As a PFI output, you can route many different internal AI, AO, DI, or DO timing signals to each PFI terminal. You also can route the counter/timer outputs to each PFI terminal.
 
Using the hardware mentioned above, here are the steps to internally route PFI0 to CTR 0 SRC in LabVIEW starting from the DAQmx “Count Digital Events.vi” shipping example:
 
  1. On the block diagram, insert a channel property node between the DAQmx Create Virtual Channel vi and the DAQmx Start Task vi.
  2. On the channel property node select the CI.CountEdges.Term property (Counter Input» Count Edges » Input Terminal).
  3. Right-click on the property node and select “change all to write”
  4. Right-click on this terminal and select “create » constant”
  5. On the constant you created, drop down and select “/Devx/PFI0”.
  6. Connect your external signal to PFI0 and observe the Data indicator on the front panel increase.
 
In order to do this in Visual Basic, starting from the DAQmx “Count Digital Events.vi” shipping example, the following line of code must be inserted right before the start task.
 
DAQmxErrChk DAQmxSetCICountEdgesTerm(taskHandle,"Devx/ctr0", "PFI0")
 
As an additional note, it is necessary to ensure that internal routing is possible by examining the device routes in MAX. Please refer to KB 3WRGIUOC for additional information on how to verify this.
 
For additional forms of internal routing, it is encouraged to look at the “DAQmx Connect Terminals.vi” in the LabVIEW help.


Related Links: KnowledgeBase 3PM84L8T: What Do the Signal Names On My DAQ Card Mean?
KnowledgeBase 3WRGIUOC: How can I know what internal routes are available on my device?
Product Manuals: M Series User Manual (April 2006)
Product Manuals: BNC-2111 Installation Guide


Attachments:


BNC-2111 Signals.JPG - BNC-2111 Signals.JPG
Connector.JPG - Connector.JPG

Report Date: 10/13/2006
Last Updated: 12/07/2006
Document ID: 42CBSK07

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