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displaying multiple indicators from the daq assistant

I am acquiring several seperate signals (voltages) with a DAQpad-6015. In LabVIEW I have created indicators for each input and have connected them to the DAQpad-6015 using the DAQ Assistant (NI-DAQmx).  From the NI-DAQmx the dynamic data is wired to a dynamic data to numeric converter and then to an inex array - to which each seperate indicator is wired to the element terminals. But, when any of the inputs is activated all of the indicators respond - like they are all connected together / not seperate!
How do I get the indicators to work independantly of each other - seperately?
Thanks for any help, I am a newby
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Message 1 of 7
I'm not what you mean by independently. With the DAQ Assistant, you've defined a task that measures multiple channels. It will always return data for all of those channels. If you know that the data from some channels should be ignored, then you can set those indicators to be invisible.
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Message 2 of 7
Thank you for the reply,
... what is happening is that if I activate only one of the inputs - all of the indicators respond, I apparently do not have something configured correctly. I am needing each indicator to respond to its particular channel - in my case any one of the inputs makes all of the guages (indicators move. I am new at this and surely have done something basic wrong. I did go through setting up the DAQpad - 6015, the self test is good, selected all of the channels, set to input and voltage. Then wired the DAQpad to a dynamic data to numeric converter and from there into an index array where each of the indicators is wired to an element terminal (of the index array).
Thanks again, hope this makes some sense.
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Message 3 of 7

I don't know what you mean by activating one of the inputs. Are you doing something in software or is this something you're doing in hardware? With the DAQ Assistant, you cannot activate or deactivate any channels that you have defined. As I said, all channels in the task will always be acquired. There is no way for the DAQ Assistant to know that something has been done externally. If you only want one channel to be measured, don't define multiple channels in the DAQ Assistant. You could create multiple DAQ Assistants and put them in a case structure. Or, as I mentioned before, if you know that only one of the inputs is supposed to be active, make the other indicators invisible.

Also, if you have multiple channels defined in a task but only one channel is physically connected, the open/floating inputs will measure the same as the physically connected channel. This is expected. Again, if you know which channel is connected, you don't have to display the other indicators or you don't have to ue the index array function to get the value. That's what case statements can be used for. But, the DAQ Assistant will still acquire all channels that are defined in the task.

It doesn't sound like there is anything wrong with the hardware or software. It just sounds like you don't quite understand how multiple channel data acquisition is done.

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Message 4 of 7

Thanks for the reply again,

I have 15 voltage inputs physically wired to the DAQpad-6015 (ai0 - ai14). On the front panel is an indicator that corresponds to each physical channel. I have set up the DAQpad-6015 with NI_DAQmx, the DAQpad is recognized and passes the self test. All (15) channels have been selected, named, voltage parameters set and the physical connections diagram has been follolwed. On the block diagram through the DAQ assistant - from the data terminal (of the DAQ Assistant) is wired a 'from DDT' converter and from that is wired an index array where all of the indicators from the front panel are wired to the element terminals (of the index array). 

My problem is that when I physically apply a test voltage to one of the inputs into the DAQpad-6015 all of the indicators on the front panel respond - that is the whole bunch of them (all 15) move exaclty the same!  Rats!

I think I am doing a poor job of describing what I have and am trying to do but this message is closer I think.


Your help is appreciated.

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Message 5 of 7
Like I said, if you only have one input wired, the other unwired/floating inputs will measure the same as the wired one. I repeat, that is expected. If you don't want to see this behavior, connect the other inputs to something. Why are you defining 15 inputs if only one is wired to a test voltage? That's the part of this whole issue that I don't understand. If, eventually the other 14 channels will be connected to a test voltage, your problem will go away.
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Message 6 of 7

Oh, now I hear you, yes I have all the other inputs to the DAQpad hanging in space, so you are saying that they are 'floatin', therefore will show activity on front panel. I need to connect them all. Sort of like graound them (?). I will do that.


Thank you, 

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Message 7 of 7