separating analog input data in DAQ Assistant

[topaz]

how can I separate my analog input streams coming out of DAQ Assistant?  I thought you could use the unbundle feature, but this produces an error message.   I have several voltages coming into my device, all into the DAQ assistant, but only one data stream coming out.  I need to use the individual voltages to do other calculations in the program.  This seems like it should have a simple solution.  Any suggestions?

[Dennis_Knutson]

It is simple. Just use the Split Signals function.

[topaz]

Thank you!  I am new to LabVIEW and do not have much of a programming background.  Another question for you if you don't mind.  I read in the LabVIEW help menu that I could calibrate my signals in DAQ Assistant using the calibrate tab.  I see no such tab.  Do I have to do all of my voltage-to-engineering conversions outside of DAQ Assistant? 

[Dennis_Knutson]

I think it depends on what kind of DAQ board you have whether there is calibrate tab or not. For example, I don't think you can calibrate the low-end USB DAQ devices.

If I understand you correctly, calibration is separate from converting the voltage readings to some other units. The latter is accomplished with scaling and some conversions can be done automatically. If you could explain what kind of DAQ card you are using, sensors, conversions necessary, etc. it would help to provide a more detailed answer.

[topaz]

Thank you, your help is appreciated.  I am in fact using a low end USB data acquisition board (USB-6008).  I am using this to learn how to control devices as well as record and log measurements so that I will be fully ready to use one of the higher end M-series PCI cards.  I was assuming calibration was the same as scaling, but perhaps its not.  All I need to do is to convert voltages to engineering units using my own in-house calibration curves for pumping fluids.  I have equations for those, as well as factory provided equations for pressure transducers.  From there, I use the my flow rates and pressures to calculate efficiency and other values. 

[Dennis_Knutson]

Calibration is the process of applying (in this case) a precision voltage source to the ADC inputs and comparing the outputs to an expected value. A correction factor can then be applied if there is a difference. This is done to take into account component aging, drift due to temperature extremes, etc. You are doing scaling and your scaling equations can be applied in a few different places. You can do it in mAX when you create a task or when you use the DAQ Assistant. In either, you should see a custom scaling control. If you click it and select Create New, you'll get a pop-up that will walk you through the process of creating the scale. You can always use the built-in math functions in LabVIEW to do the same thing but if you create a scale, you can just wire the output of the DAQ Assistant or DAQmx read to a graph and have your scaled values displayed.