Why do I observe zero output for my model in SimHydraulics 1.6 (R2009b)?

I have a SimHydraulics model involving a Hydraulics Pressure and Hydraulics Flow Rate sensors to measure pressure and flow rate. However, the scope gives zero output when I run my Simhydraulics model. I am using a variable-step discrete global solver and backward euler local solver for my SimHydraulics network.

Answer 1

[MathWorks Support Team]

To resolve this issue, tighten the 'Consistency tolerance' parameter in the Solver Configuration block by setting it to the default value of 1e-9.

Sensor output is zero because the 'Consistency tolerance' is large enough to not allow transient initialization. This parameter affects the nonlinear solver used for computing initial conditions and for transient initialization. It determines how accurately the algebraic constraints are to be satisfied at the beginning of simulation and after every discrete event (for example, a discontinuity resulting from a valve opening, a hard stop hitting the stop, and so on).

Decreasing the parameter value (that is, tighter tolerance) results in a more reliable time simulation.