PI controller for NXT

[xavier30]

Hi, i just tried to make a small PI (soon to be PID) controller for integer numbers, since there are no floating point awailable in the NXT. As i understand from the documentation provided with the NXT toolkit, there is a built in PID controller in the output properties for the NXT? Have any of you tested out this controller in LabVIEW (fishing for examples here , since i often fint this more explaining than the documentation itself, and im a bit lazy)

This is my own version of the PI controller for INT32, but im wondering if i should rather use U8 or something similar?

This controller multiplies the proportional gain and the integration time by the factor "Scale" so that you keep some of the desmal points which you otherwise would get from floating points. Then it scales down the output and saturates it to the proper limits of the actuator, and also prevents "windup" from the integer of the error.

Can some of you please give me some feedback of these blocs, and help me figure out if i did some calculating errors converting from double to integer?

(Bu the way, the scale defines the value you have to multiply KP, Ti and h with, Kp is the gain (opposite to PB which is 1/KP), Ti is the integral time relative to the scale and h is the step "length")

Cheers^^

X

[laca]

One good info new starter, Thanks.