Hello. I have LV2014, using a USB-6002 DAQ, password to my attached Vi is "2015". The Vi runs the way I need it to, although I am sure I probably could have programmed it better. The issue I have is with my voltage in from my Marchand power amp. The power amp is driven by the USB-6002 and then provides a 0-2mV signal back to the USB-6002, which is then scaled to represent 0-200VDC. On the main Vi "Piezoelectric displacement test v.2 launch", front panel, "Program Run" tab, under the communications headline are my coms locations. The issue I am having is with the one labeled "Volts from Amplifier". When the Vi runs correctly, under the "Voltage" column of the array to the right of the coms section is reading what is coming from the Marchand, after it is scaled. I am having trouble getting this repeat voltages. Last week Friday it ran fine. No changes were made to the Vi, over the weekend. Today, my values are not repeating and not scaled properly. I make changes to the values for "calibration" on the tab labeled "Alarms/Errors", from the front panel. The array should be reading 0,20,40,60,80,........200. The scaling takes place on the block diagram, in case named "Test in progress". It is labeled "Current Test Voltage", as an output after scaling. In the folder with my main Vi is my sub-Vi's that I use here. I have put an O-scope on the monitor voltage from the Marchand Amplifier and it is reading correctly. I put an analog meter on the 0-200VDC output from the Amplifier and it is correct (0,20,40,60,80,.......200). So, the only place it could be is in my Vi but I have tried re-writing everything pertaining to that scaled voltage value but it changed nothing. To rule out the USB-6002 I moved it to another channel, same problem. I realize my "Test in Progress" case has repeat code but nothing else I tried, worked. I really have run into a wall here and don't know what else to try. I tried another piezoelectric device to test but it had no affect either. I would appreciate if you would please see if there is something I missing as well as welcome any feedback you may have about my project in general, as this is my first Vi. Most pressing however, is that I can't get a steady, repeatable value. Thank you

Right, so it's meant to ramp up from 0 to 5.5 in increments of 0.5, which is why you run 11 iterations with each loop. So logically, you should be sending out 0, 0.5, 1, ... 5.5 and receiving back the same values. If you're not seeing zero as the first value, then I believe that means you're either sending the wrong value out, or you're reading at the wrong time before it's had time to settle. Try messing with your timing a bit and confirming that the outputs are what they should be. If it worked to use simple DAQmx VIs instead of those subVI's why don't you just do this? Your subVI's are waaaaay overkill in terms of starting and stopping the tasks. You can just Start each task once at the beginning and Stop at the end. Otherwise I don't know what's wrong with your current setup, which usually points to timing issues.