The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design Languages >> Verilog-AMS >> a question about fluidic sys. in Verilog-AMS
https://designers-guide.org/forum/YaBB.pl?num=1071722712

Message started by lily on Dec 17^th, 2003, 8:45pm

Title: a question about fluidic sys. in Verilog-AMS
Post by lily on Dec 17^th, 2003, 8:45pm

???
Hi,

Does anyone know how to describe the fluidic system in Verilog-AMS? I cannot find any "discipline" or "nature" corresponding to it. However, I know VHDL-AMS has Fluidic nature.

Thanks,

lily

Title: Re: a question about fluidic sys. in Verilog-AMS
Post by Ken Kundert on Dec 17^th, 2003, 11:03pm

I don't believe there is a fluidic discipline available from "disciplines.vams". However, it is relatively easy to create your own natures and disciplines.

-Ken

Title: Re: a question about fluidic sys. in Verilog-AMS
Post by lily on Dec 18^th, 2003, 12:01am

:D

Thanks for your reply! Do you have any example about how to create it and the corresponding access function etc. ?

lily

Title: Re: a question about fluidic sys. in Verilog-AMS
Post by Ken Kundert on Dec 18^th, 2003, 8:02am

I can give you and example of the syntax, but I am not familiar enough with fluidic systems to be able to choose the right quantities, units, and tolerances.

First you have to define the natures. These describe the signals that you will be using. In fluidic systems, I'm guessing that the models will be formulated in terms of pressure and flow or flow rate. You would probably use flow if the fluidic movement were a finite displacement, and flow rate if were a constant stream. The natures might look something like these ...

// Pressure in Newtons per square meter
nature Pressure
units = “N/m^2”;
access = P;
abstol = 1p;
endnature

// Flow in cubic meters
nature Flow
units = “m^3”;
access = F;
abstol = 1p;
endnature

// Flow rate in cubic meters per second
nature FlowRate
units = “m^3/s”;
access = FR;
abstol = 1p;
endnature

You will definitely need to adjust the abstols for these natures. Choose the largest signal level that is always negligible as your abstol. Choosing it too large reduces accuracy, choosing it too small can cause convergence problems.

Finally, you need disciplines, which are nothing more than a pairing of natures.

// Displacement Fluidic
discipline displacement_fluidic
potential Pressure;
flow Flow;
enddiscipline

// Stream Fluidic
discipline stream_fluidic
potential Pressure;
flow FlowRate;
enddiscipline

-Ken