BEST Local GUI
BEST
User’s Manual
30
Figure 22
: PID Parameters window
The feedback actuation frequency (“Freq” in the PID configuration menu) is obtained
by averaging the phBPM source signal (always sampled at 100 kHz) by an integer
number of samples. For this reason, only a discrete range of frequencies ("Real freq"
in the PID configuration menu) corresponding to integer multiple of samples in the
averaging algorithm can be obtained. If, for example, the user selects Freq = 100 Hz
the averaging is performed on 1000 samples and “Real freq” will exactly be 100 Hz,
while if the user selects 90 Hz the average is performed on the closest possible integer
number of samples (1112) and “Real freq” of the PID will be 89.928 Hz, slightly
different from the one required by the user. In other words, the “Real freq” field
shows the nearest, real and applicable actuation frequency value based on the required
“Freq” setting.
The
usual K
p
, K
i
and K
d
parameters are needed to calculate the well-known PID
algorithm (
). There are also several other parameters available to the user;
they can further optimize and fine tune the PID controller and therefore improve
system performances.
