Digital Multimeters (DMMs) and Precision DC Sources

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dmm switch synchronous scanning - different versions of VIs, moving VIs, compatibility

Labview 8.0 on my controller equipped chassis (pxi6229,pxi2503,DMM4060)
Labview 8.0.1 eval on my laptop (simulated hw) for when I don't have access to the actual HW.

I am using the pxi4060 with the pxi2503 mux in single-ended mode to measure a series of DC voltages.
I have modified the "DMM switch synchronous" and it seems like it will do the job.

When I copy the vi to my laptop and try to open it, it can't find half of the components necessary in the block diagram. 
Even if I use the example finder on my laptop to open what should be the exact same DMM example I started with, it still cant find
some components. If I force it to continue I can see that it isn't the same example I expected.

So - is the eval version crippled in this way?
Are the installations really that different from v8.0 to v8.0.1?
Are these examples part of the Labview install, or could this be due to different versions of VISA or MAX?

I have successfully moved several VIs I developed on my laptop to the chassis platform, and my major hurdle so far has been that
device names under simulated HW are different from actual device names, and that some HW functionality cannot be simulated.
This is not a big problem since just having the capability to create and edit VIs with partial funtionality is useful.

Is there any way I can get my Laptop install to more closely match my chassis install without buying another license?
What SW packages would I need to check to insure compatibility?
After spending a good deal of time installing and re-installing different SW packages and finding there are still parts missing is frustrating.

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Hello tadk,

When you say that the laptop can’t find half of the components, are these components DMM and/or SWITCH VIs or are they a different kind? What are some of the names of the missing VIs?

If they are DMM and/or Switches VIs then the problem can be resolved by downloading both the DMM and the Switches drivers on your laptop.


You can find a copy of the latest version of the drivers on our Drivers and Updates website.

The DMM driver is located under Measurement Hardware>>Digital Multimeter and the Switches drivers is located under the Switches link at the bottom of that same website. This should resolve the problem of the missing VIs.

Concerning the hardware names problem, you can change the names of the simulated devices to be the same as the real devices on the other machine using Measurement and Automation Explorer (MAX). Just right click on the simulated device and change the name to match the name on your other system. You should be able to run the same VI on both computers even though you have the evaluation version installed.

Let me know if this doesn't work or if you have any questions.


Tica T
Applications Engineer
National Instruments

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Thanks, one of the phone support people pointed me to the downloads page. After downloading both the switch and dmm packages, the VI loads successfully.
There sure are a lot of different pieces to install to get things working - and no clear path as to what is needed other than these forums.

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One additional problem I am having my scan list is not interpreted correctly.

If I use "ch0->com0; ch1->com0; ch2->com0;"  with # of samples set to 4, what I get is an array of results in the order ch1,ch2,ch3,ch0.

My workaround is to add a dummy channel to the beginning of the list, but there also seems to be a problem with the last result not being
the correct one either forcing me to add a dummy entry on the end too. It also complains about the number of samples not matching the number
of scan list entries even when they do match.


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Hello Tadk,

On your previous post you mentioned you made some modifications to the DMM Switch Synchronous Scanning VI. Is it possible that the changes have anything to do with the way the switch is behaving?

Can you try running the original example? Notice that by default the scan list is "ch0:5->com0;" which will read channels 0 through 5. Try this with your system only ready channels 0-4 to see if this allows you to measure the values in order.

Let me know if this makes a difference.

Tica T
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I have played around with this for too long. It is very repeatable so I am surprised it has not been complained about before.
The scan list format I am using is one of 3 accepted formats, and the only one that makes sense for me.

You might suggest I scan all my nodes every time using the range format, and  just use the data I want, throwing the rest away.
The time to scan all 40 nodes I am interested in every time I just want a few is way too long. In the procedure I am creating there will
be dozens of such scans. NI knows about the bug. It is a simple thing to demonstrate if they care to. The only thing you need to change
in the example is the scan list. I'll use my workaround until they get around to fixing it.
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