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Design Languages >> Verilog-AMS >> Maybe a stupid question
https://designers-guide.org/forum/YaBB.pl?num=1408370307

Message started by Ciprian on Aug 18^th, 2014, 6:58am

Title: Maybe a stupid question
Post by Ciprian on Aug 18^th, 2014, 6:58am

Maybe is a stupid question as the subject says.
Can anyone explain me the role of Theta and Tau functions and what they do?

analog begin
V(vp, vn) <+ Km*Theta(shaft) + Rm*I(vp, vn) + ddt(Lm*I(vp, vn));
Tau(shaft) <+ Kf*I(vp, vn) - D*Theta(shaft) - ddt(j*Theta(shaft));
end

Title: Re: Maybe a stupid question
Post by boe on Aug 18^th, 2014, 7:06am

Ciprian,
what is the discipline declaration of shaft?
- B O E

Title: Re: Maybe a stupid question
Post by Ciprian on Aug 18^th, 2014, 7:09am

Is rotational.

Title: Re: Maybe a stupid question
Post by boe on Aug 18^th, 2014, 7:13am

Ciprian,
please check the discipline.vams file.
Mine reads
Code:

... // Conservative disciplines
discipline rotational
potential Angle;
flow Angular_Force;
enddiscipline

discipline rotational_omega
potential Angular_Velocity;
flow Angular_Force;
enddiscipline

It also defines Theta and Tau.
- B O E

Title: Re: Maybe a stupid question
Post by Ken Kundert on Aug 19^th, 2014, 10:45am

So, Tau is an access function that is used to access the torque on the shaft, and Theta is an access function that accesses the rotational angle of the shaft.

-Ken