Define a physical channel in MAX

[bmann2000]

I'm finding it difficult to locate the answer to what seems like a very easy question.

I have hardware differences between machines, but they all run the same LabVIEWapplication.exe

Hardware pins are defined in MAX as Task Names, as shown in the picture below.

I've started using the edge detection feature of the PCI-6515 card, but I cannot figure out how to define a physical channel in MAX for the edge detection input of DAQmx Timing.vi, shown below as Dev3/port0/line2. In MAX, task name "DI_InsideWin1" is defined as Dev3/port0/line2 but Task Names cannot be connected to the "falling edge physical channel" input of DAQmx Timing.vi.

How do I define that input in MAX such that I can deploy the same exe to all machines?

[GerdW]

Hi bmann,

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@bmann2000 wrote:

How do I define that input in MAX such that I can deploy the same exe to all machines?

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You need to set a unique alias for the DAQ card (PCI-6515), like "DEV-6515", instead of the generic "Dev3".

In the VI you can name that pin "DEV-6515/port0/line2"…

[bmann2000]

many thanks, seems obvious now.

have tested the code and can confirm this works.  The Physical channel PCI-6515-01/x/x appears in the browse window when you click on the Physical Channel Constant.  I will now need to update MAX on all machines to name the Dev3 card as "PCI-6515-01".

[GerdW]

Hi bmann, 

instead of fiddling with MAX on each and every computer I prefer to search for the daq device using DAQmx property nodes...

You can also define DAQmx tasks within your LabVIEW project: also no need to work with MAX.

[bmann2000]

I cannot figure out how to define the Physical channel as an Alias in MAX to make the LabVIEW app tolerant to differences in the physical connections.  I figure I need to learn how it all works first, then build up to using other methods of referencing the physical pins.

The LabVIEW application uses edge detection.  The Digital Input for edge detection is PCI-6515-01/port0/line0 on one machine, but is PCI-6515-01/port1/line0 on another machine.

The Task DI_InsideWin1 points to PCI-6515-01/port0/line0 on one machine, and PCI-6515-01/port1/line0 on the other.

DAQmx Timing.vi wants a second input named "falling edge physical channels". 

How do I create a reference for this input that will work for both machines?

[GerdW]

Hi bmann,

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@bmann2000 wrote:

The LabVIEW application uses edge detection.  The Digital Input for edge detection is PCI-6515-01/port0/line0 on one machine, but is PCI-6515-01/port1/line0 on another machine.

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Why do those machines differ at all?

Anyway: your VI can also determine the machine it is running on, either by checking some properties of the computer (like computer name) or by reading a config file.

Based on that information you can select the right pin for edge detection…

[bmann2000]

The PCs are the same, same PCI Cards etc.  Some of the signals are connected to different physical pins.  I've always used Tasks in MAX to accommodate these differences, this worked well from 2013 to 2020 when I started using the edge detection feature of the PCI-6515 Card, now I'm finding the DAQmx Timing.vi has an input that I do not seem to be able to define in MAX, even though it's the same pin as the Task going into the same VI.

Should I give up and just move the wires?

[GerdW]

Hi bmann,

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@bmann2000 wrote:

Should I … just move the wires?

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Well, I prefer to have the very same setup when I duplicate a testbench!

You only need one LabVIEW source/project…

You only need one electric schematics…

You only need one documentation for both testbenches…

[bmann2000]

Not always within my control.  We're a manufacturing facility and the machines are upgraded at various times when workload allows.  As we're constantly developing new improvements, once improvements are qualified on one machine, the setup is then replicated across all machines in a series of staged upgrades.

Thanks for your help, I'll try an SSP request to bottom out if this is possible.

[bmann2000]

SSP request suggested this method, which does not work.

Then this method, which does work, but suggests using a config file.  This already exists in the MAX .nce file, so another file is not a solution, just a duplication of files.