High and low limits for AI in DAQmx

[jliu317]

What is the easier way to measure an analogy input line in DAQmx while placing a high and low threshold for the input, and output a boolean if the value is not within the limit?

[Dennis_Knutson]

Why don't you simply set the max limits and get the maximum of the returned array?

[jliu317]

can you set an example?  i'm new to labview.

[Dennis_Knutson]

Search for 'array min and max'. The greater than or equal should be easy to find.

Are you looking for some specific threshold? Trying to avoid saturation, something else? You do know, don't you, that the limits you set are not necessarily thr min and max of the adc?

[jliu317]

Thanks for the advice but you're missing the point.  I'm not looking to get the max and min.  I need to set a threshold for AI.  If the actual AI readback is greater or lower than that min or max set by the virtual channel, it triggers a boolean output saying fail or pass (i will use a boolean LED indicator for that). 

[M.Q]

yes. u have to set exact values  of input that is described in manual. i was getting same problem previous days and when i set it values accordingly to manual of hardware using. all goes well. it does not allow range of input  to exceed

Hope this will be helpful.

[jliu317]

When you mean it does not allow range of input (AI), what happens?  Does it produce a boolean value?  I need this boolean output to trigger my boolean LED indicator.  Also just to be clear, it's an analog INPUT, not an OUPUT where a user has to set an output value.

[M.Q]

I'm not looking to get the max and min.  I need to set a threshold for AI

look at ur previous reply, u want to know how can i set range of AI. i just tellu about that i experience. i donot know what uwant to get output. u also not put any code so how can i know  what u want to output

[Dennis_Knutson · Accepted solution]

You have to do a comparison of the array you read and see if the MAX value exceeds your limit. This will generate a Boolean output. The DAQmx Read by itself will not return anything except s clipped signal if the signal exceeds the range you set.

[jliu317]

Thank you, finally someone gets it.