OK... Lets take a few steps back, because we don't know what you are trying to do and the VI you attached looks good if you are trying to perform a pulse width modulation to generate a signal. Secondly, are you still trying to connect the DAQ directly to 30 volts without any signal conditioning, because if you do it will destroy it.
Lets start with the basics. Open up Measurement & Automation Explorer, click on Devices and Interfaces, then find your DAQ board. Right click on your DAQ board (typically device 1) and select properties. Change the AI mode to RSE and the polarity to -10V to +10V and change your AO polarity to Bipolar. Click OK. Now right click on the DAQ board and select Test Panels. Feel free to play around with this to get use to how things work. You might want to connect pin 22 (analog output channel 0) to pin 68 (analog input channel 0). You can then switch back and forth between the analog output and the analog input tabs. You should see the waveform outputed from the analog output channel 0 on the analog input channel 0, because you have wired pin 22 to pin 68. Note that they share a common ground so only one connection is required. Since you are using RSE, you could connect and measure the voltage of a battery that is below 10V by connecting pin 68 (analog input 0) to the + terminal of a battery and pin 67 (analog input ground) to the - terminal of the battery. Get use to doing this and measuring the values of batteries and looping the analog output to the analog input before continuing.
Next, I would recommend starting with the DAQ shipping examples. Attached is one called Cont Acq&Graph, that does exactly what it says. Once you open it up Click on File:VI Properties and then change the category to documentation and read what this VI was designed for. I would recommend leaving all of the defaults as they are until you figure out what each one means. Again, try measuring the voltages of a battery and I would recommend opening up the block diagram and opening the help for each sub VI until you have a good understanding on each one.
Finally, you can start researching signal conditioning to figure out what you will need to do, before measuring a voltage larger than 10 volts. I would recommend a SC-2045 with at least one
SCC-AI01 module. You can add additional modules if you need to measure more than 2 high voltage channels. Or you can build your own voltage divider circuit if you feel up to the task and have a strong EE background.
Note that all of the pins that I have mentioned refernce the recommended 68 pin connector like an TBX-68 or a SCB-68 that is recommend for the DAQ boards. The conversions are below for a 68 to 50 pin adapter:
68 Pin | 50 Pin
22 | 20
67 | 2
68 | 3
Joshua Prewitt
National Instruments
