NI-DMM/Switch Express Capacitance

[Clecio]

Dear friends:

I have a multiplexer system to measure 12 capacitance channel and I'm using a PXI-2503 with TB-206 and a PXI-4072. I tried to developed a VI using NI-DMM/Switch Express but when I run this express, it shows a message in attachment. Can you help me please? I did measures in Voltage, Resistance and Current mode and works perfect.

Thanks a lot.

[Zvezdana]

Hi Clecio,

Please give us some more information about your setup:

Are you using TB-2606 or TB-206?

Could you attach the project file?

Did you try to generate the LabVIEW code from SignalExpress and run the VI? Do you get the same error?

Which SignalExpress version are you using?

Thanks

Zvezdana

Message Edited by Zvezdana on 07-15-2009 10:47 AM

[Clecio]

Ok Zvezdana. Signal Express Version 3.0 

I'm using a topology "2 wire 24x1 Mux". In Labview don't occur any problem, but I can't use auto range in PXI-4072 capacitance mode.

Thank you.

[Zvezdana]

Could you also tell us if the error happens regardless of which or how many channels you use? How about if you are not using switch device at all but just try to measure capacitance with the DMM?

These answers will help us narrow down if this is a Software or Hardware problem.

Thanks

Zvezdana

[Clecio]

I tried to measure with only one channel in switch and worked, but if another channel is added, the software stop and an error shows again. If I use "SWITCH Soft Front Panel" and "DMM Soft Front Panel" together, both systems run without error. The auto-range function doesn't work in PXI-4072.

[Zvezdana]

Looking at your project, I don't see anything unusual about the configuration.  

I may not have been clear enough in the previous post; Does the error happen if you try to measure capacitance with the express VI when using only the DMM device and not use any switch devices on the switching tab? 

So, you say you don't get an error when using only one channel. Does the problem then happen only when one specific channel is added or does it happen when using 2+ number of channels, regardless of which channels those are?

If you disconnect the TB, and use those same 6 channels, do you still get the error? 

Can you reproduce it every time with those channels 0-5? Can you meausre on some other 6 channels without error?

You keep mentioning that you cannot use autoranging with 4072. I can't see how that relates to this problem because your project doesn't have the autorange selected.

Which version of DMM do you have?

Thanks

Zvezdana

Message Edited by Zvezdana on 07-15-2009 12:49 PM

Message Edited by Zvezdana on 07-15-2009 12:51 PM