Help write a program for a multi-system measurement of humidity?

[DVFU]

 Help please write a program multi-channel measurement of humidity in LabView?

I have LabView and National Instruments BNC-2120

[Blokk]

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@DVFU wrote:

 Help please write a program multi-channel measurement of humidity in LabView?

I have LabView and National Instruments BNC-2120

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We need more info, otherwise we cannot help you. BNC-2120 is a connector block. What other DAQ hardware do you use which is connected to this block?

You also did not specify what kind of humidity sensor you plan to use? Chilled mirror type, capacitive, or something else?

How many sensors you plan to use? Since you wrote you want multi-channel DAQ. What kind of signal is created by these sensors? Analogue?

What did you try so far?

[DVFU]

We use the NI USB-6361.

I need a multi-channel system for measuring voltage displayed on the chart, and then measuring the humidity, which will depend on the resistance.
Need 8 channels.
As long as there is such working hours:

[Dennis_Knutson]

You have the same channel for all. Why? You can use a single configure channel and specify multiple channels with it. The syntax is simply dev1/ai0:7. Then use an Index Array instead of the split signal.

[Blokk]

you also need to identify how you calculate the humidity from the voltage? Now you daq is a multi sample measurement, you should also decide your timing: software or hw timing, and required rate? I guess for slow humidity sensors you do not need fast daq, just read out 1 sample per channel and put a 100 msec wait timing in your while loop. So you will get 10 samples per second per channel. Use a pointbypoint mean function with sample length 10 to smouth your sensor noise. I would go this way in this case...

[DVFU]

I know. Just now, there is no possibility to connect the units and install channels. And there certainly is each used its own channel.

[Dennis_Knutson]

So what is your specific question? Why is there no possibility to connect anything?

[DVFU]

I do not understand how to change the scheme to be able to measure the humidity. Ie need to find moisture through the resistance.
And connect the blocks can not, because they are only available at the university.

[Blokk]

We cannot solve your university home work for you. What you ask is not a LabView related question, but physics. Read your text books, and search internet for your sensor specification. If you understand how your sensor works, what physical quantity it measures, and what is the physical relation between the humidity (moisture) and resistance, then you can solve your task. You told us you measure voltage. First you have to figure out how you calculate resistance from voltage, this depends on your actual circuit configuration. If you get the resistance value, you just need to find the formula to get moisture. Often moisture is expressed in Celsius degree, as dew-point. but there are other formulations as well (like %RH - relative humidity)...

Here is some reading, but google for more:

http://www.sensorsmag.com/sensors/humidity-moisture/choosing-a-humidity-sensor-a-review-three-techno...