Acquire from PXI 5105 Scope and PXI 4071 DMM at same time

[Muthuraman]

Hello,

I am new to PXI. The requirement is to acquire data from a PXI 5105 scope and PXI 4071DMM modules (both present in same chasis) starting at same time wthout any delay between acquisition.

I know that this is possible using Star signal from PXI. 

I have code for individual acquisitions from PXI 5105 and PXI 4071 seperately. Can anyone brief me on how to configure Star signal or rather help me with more clear thoughts on how to achieve this requirement.

Thanks in advance.

Regards,

Muthuraman S

[Steve_B]

Hi Muthuraman,

What mode are you using your DMM in? It can be configured to take typical DMM measurements or it can also be set to acquire waveforms. The Digitizer and DMM can both be configured to start based on a trigger. The Digitizer will be able to acquire data based on an external sample clock if necessary, however the DMM can only operate based on its own internal clock. The DMM clock is not going to PLL to the PXI chassis backplane clock so there will likely be some phase error between the two devices' sample clocks. The measurement rate of the DMM will depend on the settings and mode it is used in. I have attached some images from the DMM Help file that explain more about the measurement cycle and also the default configuration when you are in the waveform acquisition mode.

We do have example programs that could help you get started on this type of application. In LabVIEW they can be found by going to Help>>Find Examples. Within the Example Finder you can navigate in the middle window to Hardware Input and Output>>Modular Instruments>>NI-DMM>>Acquiring Waveforms (assuming you are in waveform acquisition mode) or NI-Scope>>General.

The DMM Example I would recommend looking at would be Triggered Waveforms.vi. The Scope example I would recommend starting with would be NI Scope EX Configured Acquisition.vi. 

You will want to configure both VIs to use a trigger based on your desired trigger line.