04-14-2010 11:17 AM
I am semi-new to Labview. I have looked at a bunch of guides and such but still am stuck. What I need to do is pretty simple but am stuck.
Using Labjack, I wanted to be able to calculate the voltage, RPM, and wind speed of this wind turbine we are building.
When we do this, I just want it to graph it.
I am kinda new, and I dont expect anyone to do this for me, but if someone can point me in the right direction Id be thank ful.
04-14-2010 12:15 PM
Not sure what labJack is.
You will need a data acquisition device (most likely a headless one unless you will leave a computer in the nacelle), a voltage transducer (generator voltage I presume), and a pulsing tachometer signal - perhaps from a proximity probe on the gearbox to generator shaft, or on the main shaft. Windspeed sensors typically come with a daq device and provide either an analog output proportional to wind speed or use a rs232 communications protocol.
So with your data acquisition board you can use the NI data acquisition LabVIEW functions (express VI is easiest to use) and wire the output of the function to a graph.
If you want to try this without hardware, you can also use an express VI to simulate data and create a graph display.
Does this help
04-14-2010 02:34 PM
Are you able to read the values into LabVIEW from the Labjack device? Labjack provides some examples here if not: http://labjack.com/support/ud/examples/labview.
Labjack's API doesn't appear to be as easy to use as DAQmx and you won't be able to use the Express VI that Preston mentioned (since it's only for NI DAQ devices).
Once you get the values - creating a graph in LabVIEW is simple; just add it to the front panel and wire values to it (you can send multiple signals to the same graph by creating a 2D array and passing it to the graph).
04-14-2010 06:41 PM
Tell us more about the signals you have, and we can help you get going. Is the voltage AC or DC and what is the max/min. What type of signals do you get from your RPM and Wind Speed sensor?
04-15-2010 12:26 PM
Thanks guys for your help. Heres what we have so far..
The voltage is in DC, and the max is 15 V
I am confused about what you mean in signals. Sadly I am doing this with little to no knowledge in circuits. My major is totally different, but due to class requirements, I need to do this.
Heres our ideas so far. We planned on anemometer in order to read the RPM and wind speed. To do this we planned on making our own, and attaching a reed switch onto it, to get the amount of revolutions (RPM).
The picture below (I dont know if pictures work here or not) is a simple drawing of how our circuit would or could look like. The generator is connected to the wind turbine.
The green is how the voltage would be measured.
If there is anyone you might need, please ask, and thankyou for all your help to everyone.
04-15-2010 05:43 PM
Which LabJack do you have? If you have a choice, the U3-HV should be a good way to go.
So are you going to have 2 reed switches? One for wind speed and one for RPM? It might be better to use something solid state like a hall-effect sensor or some sort of opto sensor, so you don't have to worry about the bounce of a mechanical switch.
It looks like you also show a transistor controlling a relay. If you use a solid-state relay you can control it directly from a LabJack without the transistor.
04-16-2010 01:21 PM
Thanks for the reply. We are required to use Labjack U12.
We decided to change some things up, due to complexity and time constraint. Instead of using just the anemometer, we are going to use a tachometer to measure the RPM's and just use the anemometer's screen (displays wind speed) for the the wind speed portion.
Now here are the measurements we are required to have:
1) RPM (GRAPH, tachometer)
2) Wind Speed (NO GRAPH, just using what the anemometer gave us)
3) Amperage (GRAPH, by using a volt meter. We dont know what ones are able to be incorportated with Labjack)
4) Voltage (GRAPH, directly between the generator and relay point)
From what we understand, this is not the BEST way to do it, but based off of money (we are college students here ) and it being due in 2 weeks, we felt this would be the best way.
Now is there a certain volt meter or tachometer that would work best with Labjack?
04-19-2010 11:50 AM
1) This comes back to questions from my last post.
2) So, you are just going visually read this from a display and record it yourself? Thus it does not involve the U12 or LabVIEW?
3) We can help pick a current sensor. What is the max current?
4) The 15 volts max measurement is no problem. I would work on a Google Drawing of your wiring and we can help: