Dynamic control questions?!!

[abc-123]

Dear all, I got one problem when I used the PID control toolkit to obtain the dynamic control response. When, I input the sinusoidal signal to the system under PID control, the frequency for the output signal is 5 times larger than the input. For example, when I input frequency 0.1 Hz, the frequency of the  output signal is 0.5 Hz. I do not know why, and the frequency shouldn't be changed. Amplitude and phase may change. the attachment photo is the block diagram and the program files can be running when they are put in the same directory.

Thx!!

Message Edited by SarahM on 05-21-2007 07:50 AM

[abc-123]

Pls do me a favor

Thx

[Brian_Beal]

It all depends on your tuning.  It is possible to have a steady state input, but oscillating output.

[abc-123]

Hi, my problem is when I input one sinusoidal signal with one frequency of 0.1Hz to the PID control system, the frequency of output sinewave always 5 times faster than that of the input and the programs are the attachments. However, the frequency should not be changed anyway according to the theories. I can not find where the problem is.

[ztyaner11]

Could you show me the parameters you used?

[abc-123]

sure! The amplitude and frequency of the sinusoidal signal is 0.5, 0.5Hz respectively, while , the PID control parameters are Kp=0.8, Ti=5.2 and Td=0.4.

[Allison_S]

abc-123,

    I just wanted to let you know that we removed the code in your previous post (PID dynamic.zip).  This contained your VIs but it also contained some of the VIs from our licensed and purchasable PID toolkit.  In our Terms of Use under Intellectual Property and Your Condict it references posting protected software.  These VIs from our toolkit cannot be posted on the forums, but feel free to repost your own code.  Thank you!