Coils_X_3 $—$ Interface for a coil of a three-position directional control valve

The Coils_X_3 component describes the spool position of a directional control valve that has two coils.

The commanded opening of the valve is input at $\mathrm{commandA}$ or $\mathrm{commandB}$, respectively. The position of the spool ($\mathrm{spoolPos}$) is modeled as a first-order system.

Input signals: $\mathrm{commandA}$ and $\mathrm{commandB}$.

When $\mathrm{commandA}=\mathrm{true}$ and $\mathrm{commandB}=\mathrm{false}$, then $\mathrm{spoolPos}=-1$.

When $\mathrm{commandA}=\mathrm{false}$ and $\mathrm{commandB}=\mathrm{true}$, then $\mathrm{spoolPos}=1$.

Otherwise, $\mathrm{spoolPos}=0$.

Intermediate positions are also modeled.

The movement of the spool is described by a first-order system. This is appropriate for valves that are directly actuated by a spool. The time to shift from the neutral position to an end position (${\mathrm{\tau }}_{\mathrm{opening}}$) may be different than the time to shift to the neutral position (${\mathrm{\tau }}_{\mathrm{closing}}$).

 Equations $\mathrm{spoolPos}={\mathrm{spool}}_{\mathrm{position}}$ $\mathrm{tau_spool}=\left\{\begin{array}{cc}\frac{{\mathrm{\tau }}_{\mathrm{opening}}}{3}& \mathrm{commandA}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathbf{or}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathrm{commandB}\\ \frac{{\mathrm{\tau }}_{\mathrm{closing}}}{3}& \mathrm{otherwise}\end{array}\right\$ $\mathrm{tau_spool}{\partial }_{t}\left({\mathrm{spool}}_{\mathrm{position}}\right)+{\mathrm{spool}}_{\mathrm{position}}=\left\{\begin{array}{cc}-1& \mathrm{commandA}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathbf{and}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathbf{not}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathrm{commandB}\\ \left\{\begin{array}{cc}1& \mathrm{commandB}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathbf{and}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathbf{not}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}\mathrm{commandA}\\ 0& \mathrm{otherwise}\end{array}\right\& \mathrm{otherwise}\end{array}\right\$

Connections

 Name Description Modelica ID $\mathrm{commandB}$ Command signal for valve commandB $\mathrm{spoolPos}$ spoolPos $\mathrm{commandA}$ Command signal for valve commandA

Parameters

 Name Default Units Description Modelica ID ${\mathrm{\tau }}_{\mathrm{opening}}$ $0.03$ $s$ Switching time to open valve 95 % tau_opening ${\mathrm{\tau }}_{\mathrm{closing}}$ $0.02$ $s$ Switching time to close valve 95 % tau_closing