Using Multiple Daq

[MsCEn]

Hello,

I was working on some sensors, for example, Thermocouple and Loadcell. I have prepared 2 seperate vi's for them, but I wanted to merge them into one and see the results in one front panel.

So I put them in one VI and tried to run but it did'nt happen. Then I set one of them start 3 seconds after I push the run button, then it worked for other one but after 3 seconds process stopped.

After little investigation, I learned that some cards have only one ADC so they can't operate two analog signal output, but I am using SC-2345 and I guess that is nonsense. also for info; I am getting loadcell data from SC-2345 and thermocouple data from SCC-TC01 connectod to SC-2345. also SC-2345 is connected to NI USB-6259 screw terminal.

Conclusion; how could I get data from multiple Data accusition devices in one blok? I will porbably have to use 6 more daq in one VI, and that should be possible.

[cbutcher]

Can we see your VI (or a picture of your VI)?

[crossrulz]

You just need to set up a single task that reads all of your sensors together.

[GerdW]

Hi MsCEn,

I learned that some cards have only one ADC so they can't operate two analog signal output,

Where did you learn this?

Even when there is only one ADC such devices can read multiple input channels due to using a MUX!

how could I get data from multiple Data accusition devices in one blok?

LabVIEW comes with a lot of example VIs, so please look for yourself in the example finder…

[MsCEn]

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@cbutcher wrote:

Can we see your VI (or a picture of your VI)?

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Here is the VI file and the screenshot

[MsCEn]

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@GerdW wrote:

Hi MsCEn,

I learned that some cards have only one ADC so they can't operate two analog signal output,

Where did you learn this?

Even when there is only one ADC such devices can read multiple input channels due to using a MUX!

how could I get data from multiple Data accusition devices in one blok?

LabVIEW comes with a lot of example VIs, so please look for yourself in the example finder…

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>I can't find the link now but it was somewhere on the froum 😕

> yeah I am looking into "Analog Input - Voltage and Thermocouple in a Single Task"  example of labview, I did that for my devices but still getting errors. Also used daq assistant instead of daqmx and get this "Error -50103 occurred at DAQmx Start Task.vi:7220012" 

[GerdW]

Hi MsCEn,

how could I get data from multiple Data accusition devices in one blok? I will porbably have to use 6 more daq in one VI, and that should be possible.

It seems you are talking about different hardware devices here as your DAQAssistents are set to "dev12" and "SCC1Mod1".

If you want to read from several different DAQ devices you need to create a DAQmx task for each device. I suggest to get rid of the ExpressVIs and use the simple DAQmx functions instead!

While you are learning LabVIEW also keep an eye on proven algorithms like producer-consumer-scheme or state machines. Right now your VI looks "bad" with 2 smaller loops inside a big loop and 3 different stop buttons. Also this FOR loop to animate a tank indicator seems silly to me…

[MsCEn]

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@GerdW wrote:

Hi MsCEn,

how could I get data from multiple Data accusition devices in one blok? I will porbably have to use 6 more daq in one VI, and that should be possible.

It seems you are talking about different hardware devices here as your DAQAssistents are set to "dev12" and "SCC1Mod1".

If you want to read from several different DAQ devices you need to create a DAQmx task for each device. I suggest to get rid of the ExpressVIs and use the simple DAQmx functions instead!

While you are learning LabVIEW also keep an eye on proven algorithms like producer-consumer-scheme or state machines. Right now your VI looks "bad" with 2 smaller loops inside a big loop and 3 different stop buttons. Also this FOR loop to animate a tank indicator seems silly to me…

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Yeah it is silly 🙂 , it was in the tutorial video of NI at youtube.

I am learning labview for few weeks right now, and still trying to get the basics. I should probably use daqmx functions , I implemented one of the examples of labview -voltage and thermocouple" and finally get the results. but there is a problem, I should calibrate the voltage, normally daq assistants contains calibration, so extra question; how to calibrate daqmx? 🙂

[GerdW]

Hi MsCEn,

I am learning labview for few weeks right now, and still trying to get the basics.

Did you notice the "Getting started" section on top of the LabVIEW forum?

but there is a problem, I should calibrate the voltage, normally daq assistants contains calibration, so extra question; how to calibrate daqmx?

Where and how do you "calibrate any voltages" in your VI?

(To learn how the DAQAssistents works under the hood you can open it's frontpanel with a right-click on the DAQAssitent! Please don't get used to all the overhead you will find inside…)

[MsCEn]

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@GerdW wrote:

Where and how do you "calibrate any voltages" in your VI?

(To learn how the DAQAssistents works under the hood you can open it's frontpanel with a right-click on the DAQAssitent! Please don't get used to all the overhead you will find inside…)

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Well, with calibration I mean; I use custom voltage with excitation while working with loadcell, in the properties of daq assistant, there is a section "calibrate". so I can calibrate to 0 volt for empty state and 10 volt for maximum weight.