Hello eveyone,
I am using the 'Real Time PID Control VI' for a control application with a
PCI - NI 6035E card.
I have made some modifications to the VI in order to customize it for the
needs of my application. I added another analog input channel and a 'save to
file' possibility. I also made some small modifications to the 'simple PID'
subVI ( added initialization for the error and error sum ). Making these
modifications, I noticed that when calculating time difference ( dt ), there
is a condition that dt should be greater than 0.04 sec and if not, dt is
made to be 0.04 sec. I don't really understand why there is such a
condition, since I can use much greater sampling rates than 1 / 0.04 = 25
samples per sec. I changed that condition to a much smaller nu
mber and
everything seemed to work fine. Though, having some problems with the
response of the closed loop system I started wondering if that condition is
some kind of a lower limit for the differential time space the VI can work.
Can anybody help me ?
Thank you in advance,
M.