Parallel Data Acquisition using PXI 6070 E, PXI 4071 and LabVIEW.

[Shaheen]

Hello seniors,

I am using NI LabVIEW, NI PXI 4071, and NI PXI 6070E to measure current through a variable resistance. Right now I am using one channel from SCB-68, but I want to add another channel in parallel so that I can have two resistors instead of one that I cam measure current through them.

I have attached a Pdf file showing the setup for hardware in use and LabVIEW code also.

Can anyone look at these files and give me guide lines or ideas that can help me resolving this issue, please.

Thanks in advance.

Best Regards,

Shaheen.   

[Kyle_K]

Do you want to measure them at the same time or is it acceptable to read one right after the other very quickly?

Kyle K.

[Shaheen]

I wana measure both at same time.

[Kyle_K]

Are you asking about how to generate two signals from the PXI 6070E or how two read both resistors from the DMM?

Kyle K.

[Shaheen]

I am trying to read both resistors from the DMM in parallel.

Best Regards,

Shaheen.

[Kyle_K]

A DMM only has one channel and can therefore can only read  one value at a time. To measure both at the same time, another DMM will be required. Often we use a switch card to quickly move from one circuit to another to allow the DMM to measure multiple circuits very quickly, but this does lead to slight time delays between the measurements. If switching back and forth will provide you with measurements that are "close enough" to be considered simultaneous for your application, then it could be done with a single DMM. Depending on the level of accuracy you require, it may be useful to use a multifunction DAQ card that can have simultaneous AI sampling instead of a DMM. 

[Shaheen]

Thanks a lot for your suggestions.

Can you send me links of a multifunction DAQ, the most suitable will be the one that can measure capacitance and inductance also.

I will really appreciate it.

Best Regards,

Shaheen.

[Kyle_K]

The NI PXI-4072 DMM is the only thing that will directly measure inductance and capacitance. Depending on what you are trying to do (big picture) with the measurement, the recommendation may change. If it is acceptable for your application, it is possible to build a small circuit that relates inductance or capacitance to a voltage that can be measured by a Multifunction DAQ card. You would then be able to utilize the simultaneous inputs we mentioned earlier.

Kyle K.

[Shaheen]

Hello NI,

I talked to my research group and we have concluded to measure 2 channels one after the other.

It will be okay to compromise on slow speed. Now, can you guide me how to achieve this?

I will really appreciate your suggestions.

Best Regards,

Shaheen.

[Kyle_K]

Since you need to measure inductance and capacitance, you will need a PXI-4072. I would then suggest using one of our PXI Multiplexor Modules to connect that DMM to multiple resistors. Using a multiplexor will allow your application to expand to additional DUTs (Device Under Test- in this case, your resistor) in case you decided you wanted to test more than 2 at a time.  Which switch module in particular will depend on more details about your measurement. To determine the best multiplexor for your situation, I would suggest calling in and talking to one of our representatives who are available to help. Our Online Product Advisor has lots of great resources including the phone number at the top. Be sure to include the content from this forum when calling in.

-Note-

When navigating our website, we use the blue column on the left to provide links to other products in the same family. This will be useful when looking at our multiplexor modules from the link I provided.

Kyle K.