Author Topic: Meaning of "Smpl Tm" in new PID blocks?  (Read 5115 times)

Offline oiltronic

  • PLUS+1 Guru
  • *****
  • Posts: 169
  • Karma: +14/-0
Meaning of "Smpl Tm" in new PID blocks?
« on: June 04, 2014, 01:30:14 AM »
The documentation for the new PID describes the "Smpl Tm" parameter thusly:
Quote
Time between samples of the D Gain input. After ten samples, the function block calculates the average
error for the D Gain input.
Does this mean the error and derivative term is updated only once every 10*Smpl_Tm milliseconds, or is it both sampled and updated every Smpl_Tm milliseconds based on an average of the last 10 samples?

Nice new blocks, by the way.

kdcommon

  • Guest
Re: Meaning of "Smpl Tm" in new PID blocks?
« Reply #1 on: September 19, 2014, 10:19:00 AM »
D calculating updates every Smpl_Tm, but the difference calculating is based on 10 interval sampling point.
Delta = Sample[n+10] - Sample[n]
Delta1 = Sample_10 - Sample_0
Delta2 = Sample_11 - Sample_1
Delta3 = Sample_12 - Sample_2
......

You know