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how to create different types of analog input channels without using DAQ assistant?

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hello all,

            I would like to create multiple input multiple type analog channels... I mean I would like to have 5 voltage and 2 temperature channels...

However, I am not using the DAQ assistant... I am using "create channel" vi.

 

Can anyone please suggest me how to do it/ I am submitting my VI for reference.. I have 5 voltages, and 2 temperature andwould liek to display both of those in 2 seperate graphs...

 

Now on LabVIEW 10.0 on Win7
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Message 1 of 18
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I'm guessing that you need to set different values for min and max values in the DAQmx Create Channel since the first 5 channels are volts and the next two are for temperatures. If so, you either need two different DAQ cards, or you would have to read the first 5 voltage channels, stop that operation, then read the next 2 temperature channels.  You cannot setup the DAQ for two different operations at one time.

 

To use two different DAQ cards, I would do it as in the attached vi.  With one card, move all the bottom thread code to after the top thread code.

 

22489i6D69A41238FB6C3C

- tbob

Inventor of the WORM Global
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Message 2 of 18
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Hello,

         Thanks a lot for the reply. Apparently, I was wrong understanding the system. The output from the temperature sensor is given in terms of VOLTAGE,

so, I would require 7 analog input voltage channels, i think that is pretty straight forward...

 

However, I had another doubt, how to display 5 voltage channels in 1 graph and 2 voltage channels(temperature output) in another graph/??

 

The graph should be kind -of intelligent such that when user inputs 2 voltage inputs and 1 temperature input; it should show up on the chart in the same order as that of the input on respective

graphs...

 

 

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Message 3 of 18
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See attached vi.  The user has to check which channels belong to which group (volts and temperature).  There is no error checking to see if the user checked the same channel for both groups.  This will cause problems.  So be careful to choose separate channels for each group.  The data is gathered and then split according to the size of the temperature group.  Then each group of waveforms is displayed in its own chart.  You don't neet to index the waveform array to get each element, and then combine them again like you were doing.  Just send the entire waveform array to the chart.

 

22497i0C6B08DA57B5042D

 

 

- tbob

Inventor of the WORM Global
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hi Tbob, can you please send this in lv 8.0 version/??? i have lv 8.0 ...

thanks a lot ... 🙂

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Message 5 of 18
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hI tbob,

          thanks a lot for the solution... i had one more question... how to differentiate the waveform in the order of the channels... if i "stack plots", i will have 5 voltage channels and

2 temperature seperately... now, if i choose channel no. 1,3,5, 7 the waveform should display a blank channel number 2, 4, and 6... however, using the current technique,.graph shows sequential

displayof the channels (i.e. we can see graphs one below the other instead of a graph which has V1,BLANK, V3, BLANK, V5 ... )

 

can we do that/?? If I am not making sense please let me know...

 

 

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Message 6 of 18
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Not at all related to your last question but the solution has all voltage channels. You would need a different DAQmx Create Channel if you wanted a true temperature channel - one where you did not have to all of the scaling, etc. yourself.

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Message 7 of 18
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Hi dennis,

              actually, the temperature channels are voltage channels.. the temperature is sensed and converted to volts ../.. but since its temperature that we are sensing,

I am calling it a temperature channel...

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Message 8 of 18
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I am well aware that all channels are actually voltage channels. What you don't seem to be aware of is that there are specific DAQmx Create Channel functions for voltage, RTD, thermocouple, and thermistor. If you want the correct scaling, cjc, etc. applied to a temperature measurement, use the correct create channel. If you don't care about scaling, cjc, etc., then use what you have now. It's a five minute change.

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Message 9 of 18
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ooh...well, the hardware actually takes care of the scaling and all that...and makes life simple for the coders 🙂

 

so,I dnt have to bother about the scaling, cjc, etc...

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