4070 autorange

[Odd_Modem]

Hi,

I had some NI-DMM stuff for 4070 running pretty good in LabVIEW and TestStand. Then, I ran one of the LabVIEW examples that uses the DMM in waveform acquisition mode, for a test. After doing that, I went back to my original stuff, and even after power cycles, it tells me that -1.0 (autorange ON) is an invalid parameter. I need to get my code to protect against this after the bench gets out of my hands.

Now I understand that you cannot autorange the DMM while in waveform acquisition, but I can't set the 4070 up to get rid of this error (all the measurements in the original code are scalar). I have found a DMM property IVIDMMMODE, and I set that after I do the init and reset. What else do I need to do? This is NI-DMM 2.3.1, and running soft front panel does not have an effect towards clearing the error. LV7.1, TS3.1

TIA, FAS

[sead_suskic]

In helping me understand what could be happening with you application, it would be useful to get the output of NI-Spy while your application is executing - particularly when you see the error. NI-Spy will show exactly how your application calls NI-DMM. Launch NI-Spy from Start >> Programs >> National Instruments >> NI-Spy. You can use NI-Spy Help to find out more about this utility.

NI-DMM allows you to go between scalar and waveform measurements, and the best way to do that is to explicitly use niDMM Configure Measurement.vi and niDMM Configure Waveform Acquisition.vi when you need to change the mode. If you are programming the attributes through LabVIEW property nodes, you will need to configure more of the attributes explicitly - only changing Operation Mode is not enough; you would need to change Operation Mode, Function, Range (and Resolution for scalar mode) if you are going from scalar to waveform modes and back. Again, the best way to do it is to use the "configure" vis.

[Odd_Modem]

OK, I see what is happening. NI-spy is pretty good!

Just to clarify

I make an open circuit DC measurement with autorange set. The DMM sets range and then makes the measurement. Due to noise or whatever, the autorange that was set was wrong during the measurement, so the acquire returned NaN. My vi is setup to handle NaN by incrementing the range and trying again, so it set the new range to -10.0, hence the error.

As far as the association that I experienced between scalar and waveform modes of acquisistion, I don't know; it must have been me. Sorry to raise a fuss. 🙂

Now my vi says if range less than 0 multiply by 1 instead of 10. I know there is still the possibility of infinite loop that way.. Anyway, its just a while loop.

Thanks, Sead

PS. If I may be so bold, how does one pronounce yacht?