I am tyring to create a basic VI to control a level of a water tank. The water level is controlled by a valve, that is controlled by a tranducer (0 to 5 volts input) to control a preassure to move the the valve. The disturbance is another tube that goes into the tank that adds water to the tank, so when the disturbance kicks in the valve needs to close a what ever amount needed in order to keep the lelvel at the set point. The water level is measured by capacitor prbe, that outputs a different current (from 4mA to 21mA) to whatever level the water is at. I desisded to use USB-6008 to act as a A-to-D and D-to-A conversion and a digital computer to run LabVIEW with PID. The question is how do i calibrate the water tank level to read the right amount using the current coming from the probe and output a right amount of voltage to the valve? I have the PID toolkit so that makes the life easier, just the calibraton part is what is troubling me.
Thanks!
