Variable orifice

I use a Simscape block called Variable Orifice.

But when I run the model there is an error. The error text is "Cannot find error message associated with 'sh:orifice_variable:VectorSize'.

What does it mean?

[Arnaud Miege]

What parameters have you entered in the block? I suspect you have used a vector rather than a scalar for at least on of the parameters. Also, which release of MATLAB are you using?

Answer 1

[Francesca Fanfoni]

I use Model parametrization set by pressure-flow characteristic

with Tabulated orifice openings = [0 12 16 20 40] Tabulated pressure differentials: [0.5 1.0] Tabulated flow rates: [0.0001 0.0001; 0.0025 0.0055; 0.0035 0.0075; 0.0045 0.009; 0.009 0.017;]

Is it a right configuration?

[Arnaud Miege]

That seems to work just fine for me in R2011a. Which release of MATLAB are you using?

Answer 2

[Francesca Fanfoni]

R2009b

Are you sure it's the fault of the version of Matlab?

Answer 3

[Arnaud Miege]

Yes, I see the same error in R2009b. The problem is with the pressure differential values, you only provide two values and the documentation (in R2009b) for the block states that you need to provide at least 3 values:

"Specify the vector of input values for pressure differentials as a tabulated 1-by-n array. The input values vector must be strictly monotonically increasing. The values can be nonuniformly spaced. You must provide at least three values."

I agree that the error message could be more helpful. This restriction seems to have been lifted in subsequent versions. Here's what the documentation says in R2011a:

"The minimum number of values depends on the interpolation method: you must provide at least two values for linear interpolation, at least three values for cubic or spline interpolation."