Andy,
What we are trying to do is control the rate of loading on the winch i.e.. we would like to say reach 100% capacity of the load cell in 15 mins. Depending on the pretension in the tension members (recorded by the load cell) the winch would have to slow down/ speed up (via a VFD) and correct itself say every 3 secs.
I will post VIs that we used for a simulation of the above loop in a software environment. We used the PID control VI. To get the correct response, the Kp was required to be at 1. and the Kd to be at 1e-4. Any Ki would throw the response out of the window. So, I am assuming that the system would suffice with some sort of a simple linear formula that gives the required load that the load cell needs to read for a certain elapsed time and compares that to what the load cell is actually reading. Then, based on the voltage requirements of the VFD, LabView would send a signal (voltage) to the VFD asking it to slow down or speed up.
Your opinion/ critique is very much appreciated.
Thank You.
