Using DAQ assist to read voltage from 9205

[aaclabview]

I am farly new to this and I have been trying to read the voltage from 9205 which is connected to 9172. I am using it in a virtual XP mode because windows 7 doesnt run labview 8.9 . I installed the drivers for the daq.

When I check the device in Measurement in automation and Explorer, it works fine meaning the it reads the DC voltage im supplying. When I am creating a VI the daq assist , i chose the right channel, the input as analog voltage , the numeirc indicator shows it going from -10 to 10. I noticed that it did the same even after the usb was unplugged meaning the daq assist function wasnt recording data from the 9205. 

Can anyone help me?

[james88]

Well, using a Virtual Machine is not oficially supported by National Instruments. You said it works with MAX, so maybe there is a problem with your configuration in LabVIEW, or your sensor is not well conected to the module.

You can also check if the DAQ driver that you have is compatible with LabVIEW 2009, you need at least DAQmx version 8.7.2

Try to do the same test with MAX, disconnect the voltage from the module and check if there is still the same voltage

Regards

.

[MilanR]

Hi aaclabview,

Using LabVIEW and DAQ devices on a virtual machine in XP mode is not officially supported and may be prone to issues as mentioned in KB 5I74N71N: Are NI Products Supported on Virtual Machines (VMs)?

While installing LabVIEW 8.X on Windows 7 is also not supported, it has been possible to run older versions of LabVIEW on Windows 7. If you run into an error during installation from a cd, KB 53A98CUR: Windows SDK Error (-12) when Installing LabVIEW on Windows 7 may be able to help. When installing the drivers, make sure to use the newest version available for your system. At this time, it looks like DAQmx 9.4 is the newest version compatible with Windows 7 and LabVIEW versions greater than 8.6.X

In addition, an error should be recieved when trying to perform data acquisition from a device that has been removed from the system. Can you check that the device does not appear in MAX when the device is removed? Also can you verify that the icon for the device in MAX is green when the device is plugged in?

[aaclabview]

How can it not be well connected if the MAX doesn't have a problem reading values? They both use the same usb connection dont they. I also want to add that the daq ms 9205 module works perfectly well in another computer with the same exact settings. I trid unintalling the device from device manager and even reinstalled the drivers but it doesnt work. Is there someway I can reset Lab VIEW so that it behaves as a new installation without installing again?

edit: Milan I didnt see your reply, I will get back to you shortly after doing those

[aaclabview]

ok I will go into extensive detail to explain this problem. 

Current OS: Windows 7 

Running Labview 8.6 using Windows XP VM

Using a NI 9205 Dsub plugged into Ni cDAQ-9172 so I can read the change in voltage which is being supplied from a power supply.

I have attached the image from the VI. It's a basic DAQ ASSISTANT fucntion which acquires a voltage signal and nothing else. See that it does not matter whether I have the USB cable plugged in or not. It will act according the values in the right of the image ( -10 to 10). 

I did the following. I went to MAX and added a new NQ - DAQ instrument according to the simple right-click menu and clicking "add new". 

Please see the images to see exactly what I mean. I just installed the evalutation version of the latest LAbview to see if it works but right now I dont have that configured. 

I also would like to add that when I acquire the signal from SignalExpress, it shoes correct values. As in the values im supplying via the power supply. It should be a steady line and not go from -10 to 10 continuous which happens in the LABVIEW. 

thank you

[MilanR · Accepted solution]

Hi aaclabview,

The way you have added the device to MAX makes the device act as a simulated instrument. Simulated instruments only generate sinusoid data for testing a piece of code without using any hardware. A simulated device has the yellow icon as shown in the screenshot you provided and is completely decoupled from any hardware, hence adding or removing the usb device has no effect.

The problem with using Windows XP mode as mentioned in the KB above is that USB passthrough must be enabled for the Measurement and Automation Explorer inside the Virtual Machine to detect the device. Using the device in this way is not supported or recommended by National Instruments and can lead to instability and latency errors in data acquisition even if a connection is made.

It is a safer bet to try and install LabVIEW and the DAQ drivers as mentioned above on the actual Windows 7 machine than to try and run inside XP mode.