How does the RedPitaya's PID work?
Posted: Fri Oct 03, 2014 7:50 pm
Hi,
I'm familiar with basic PID controllers and have used them before. But the diagram given doesn't really make sense to me:
Some questions:
What does "SUM & SAT" mean? What is this step doing, actually implementing the PID algorithm?
Why are there 4 PID controllers? There are only 2 high speed inputs! It seems to me like you'd need 1 controller per input. So this makes no sense to me.
Why do the 2 high-speed inputs seem coupled? I just want to use one high-speed input to produce a signal on one high-speed output. Maybe I'll have two experiments going at once, necessitating the use of both inputs and outputs, but in either case I cant imagine wanting the inputs to be coupled.
Lastly, somewhat unrelated, but my redpitaya cannot be connected to the internet... where can I find the apps described on this page? http://bazaar.redpitaya.com/ There are no links anywhere on that page! Why does it even exist??
Thanks for helping to resolve my confusion!
I'm familiar with basic PID controllers and have used them before. But the diagram given doesn't really make sense to me:
Code: Select all
*
* The PID Controller algorithm itself is implemented in FPGA.
* There are 4 independent PID controllers, connecting each input (IN1, IN2)
* to each output (OUT1, OUT2):
*
* /-------\ /-----------\
* IN1 -----+--> | PID11 | ------| SUM & SAT | ---> OUT1
* | \-------/ \-----------/
* | ^
* | /-------\ |
* ---> | PID21 | ---------- |
* \-------/ | |
* | |
* | |
* | |
* /-------\ | |
* ---> | PID12 | --------------
* | \-------/ |
* | ˇ
* | /-------\ /-----------\
* IN2 -----+--> | PID22 | ------| SUM & SAT | ---> OUT2
* \-------/ \-----------/
*
*/
What does "SUM & SAT" mean? What is this step doing, actually implementing the PID algorithm?
Why are there 4 PID controllers? There are only 2 high speed inputs! It seems to me like you'd need 1 controller per input. So this makes no sense to me.
Why do the 2 high-speed inputs seem coupled? I just want to use one high-speed input to produce a signal on one high-speed output. Maybe I'll have two experiments going at once, necessitating the use of both inputs and outputs, but in either case I cant imagine wanting the inputs to be coupled.
Lastly, somewhat unrelated, but my redpitaya cannot be connected to the internet... where can I find the apps described on this page? http://bazaar.redpitaya.com/ There are no links anywhere on that page! Why does it even exist??
Thanks for helping to resolve my confusion!