I am a complete newbie to NI, Labview, and Signal Express. Earlier this month, we procured NI Signal Express 2012 for what I thought was a very simple application. Basically, I am capturing analog inputs (4 - 20 ma current) from multiple pressure sensors using NI USB 6009 as hardware to interface with the sensors and the PC/notebook running Signal Express 2012 (full version). The setup was quite simple and I am able to capture and record the raw current signals. However, when I tried to scale the 4-20 mA raw output to the engineering pressure range of -14.7 psig to 285 psig using the custom scale option (in the scale setup - I calculated multiplier/slope (18.731) and offset (-89.625) using Excel) with linear scaling I get an error -200077.... stating the property value in invalid. From what I can read in the details of the error, it appears that it is looking to receive an an analog input in the scaled range and not the raw range. I am concluding that this is not the correct place to derive the engineered value from raw signal. So, I have two basic questions:
1) Where is the proper place to convert raw electrical signals to engineering values. Keep in mind, I can always do this in excel, but I want to visualize them in realtime.
2) A related question - I don't need to sample at the rate of KHz. There are two associated values here in the setup one is number of samples and other is sampling rate. In my case, all I want to sample is for 10 minutes at the rate of 1 sample per second. So, I put in 1 Hz and 600 total samples I get an error. I reverted back to the default sampling rate and number of samples which is far in excess of my needs.
These questions are probably very basic things that should be very simple to set. Can somebody point me to where I should be looking to set these things in Signal Express 2012. Thanks!
