4-Way 3-Position Directional Valve (IL)

4-way, 3-position directional valve in an isothermal liquid system

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• Simscape / Fluids / Isothermal Liquid / Valves & Orifices / Directional Control Valves

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Description

The 4-Way 3-Position Directional Valve (IL) block models a valve with four openings in an isothermal liquid network, typically between an actuator, pump, and tank. The valve operation is controlled by a single spool displaced according to the signal at port S. You can set the baseline configuration of your valve by specifying the orifices that are open when the spool is in the neutral position (centered at 0 m) in the Neutral spool position open connections parameter, when the spool moves in the positive direction in the Positive spool position open connections parameter, and when the spool moves in the negative direction in the Negative spool position open connections.

You can set the model for valve opening in the Orifice parameterization parameter as a linear relationship or function of user-provided data, which can be applied to one or all flow paths in the valve.

Example Valve Setup

In this example configuration, Neutral spool position open connections is set to All closed. When the spool is in the neutral position, all orifices are closed to flow:

In this configuration, Negative spool position open connections is set to P-A and B-T. When the signal at port S moves the spool to a negative position, the paths between ports P and A and between ports B and T are open to flow. The paths between ports P and B and ports A and T are closed to flow:

In this configuration, Positive spool position open connections is set to P-B and A-T. When the signal at port S moves the spool to a positive position, the paths between ports P and B and between ports A and T are open to flow and the paths between ports P and A and between ports B and T are closed:

Schematically, this configuration is shown as:

The left-hand side corresponds to the positive position and the right-hand side corresponds to the negative position.

Spool Displacement and Valve Configuration

The spool stroke is the amount of spool travel an orifice takes to fully open from a closed position and is defined for each orifice selected on the Valve Configuration tab. The table below shows how the stroke is calculated in accordance with the valve orifice parameterization and flow path characteristics.

Spool Stroke Based on Parameterization and Flow Path

Orifice Parameterization	Identical for All Flow Paths	Different for Each Flow Path
Linear - Area vs. spool travel	Defined by the Spool travel between closed and open orifice parameter	Defined by the Spool travel between closed and open orifice parameter, for each orifice
Tabulated data - Area vs. spool travel	The difference between the first and last element of the Spool travel vector parameter	The difference between the first and last element of the spool travel vector parameter for each orifice
Tabulated data - Volumetric flow rate vs. spool travel and pressure drop	The difference between the first and last element of the Spool travel vector, ds parameter	The difference between the first and last element of the spool travel vector, ds parameter for each orifice

The section Visualize Orifice Openings details how to see the orientation of all valve orifices.

The direction of spool movement signaled at port S depends on the spool stroke and the orifice orientation:

Orifice Definition and Spool Travel Direction

Spool Position when Orifice is Open	Spool Travel, ΔS
Always closed (orifice is not selected in any spool position configuration)	N/A
Always open (orifice is selected in positive, neutral, and negative spool position configurations)	N/A
Negative	Sorifice_max + spool stroke – S
Negative and Neutral	Sorifice_max + spool stroke – S
Positive	Sorifice_max + spool stroke + S
Positive and Neutral	Sorifice_max + spool stroke + S
Neutral	|Sorifice_max| + spool stroke – |S|
Positive and Negative	–|Sorifice_max| + spool stroke – |S|

Where S_{orifice_max} is the spool position at the maximum orifice area defined for each orifice.

The Consistency check for neutral spool position open connections parameter verifies that

• Any orifice listed in Neutral spool position open connections is open when the signal at S is 0.

• Any orifice that is not listed in Neutral spool position open connections is closed when the signal at S is 0.

You can optionally choose to receive a warning or error when this check is violated.

The possible configurations of the 4-Way 3-Position Directional Valve (IL) block are shown below.

Note

This block includes all configurations from the Hydraulic (Isothermal) library blocks 4-Way Directional Valve and the 4-Way Directional Valves A – K.

4-Way 3-Position Directional Valve Configuration

Configuration	Parameter Values
	All four orifices are closed in the neutral position. (default) Positive spool position open connections: P-A and B-T Neutral spool position open connections: All closed Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
	All four orifices are open in the neutral position. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-A, P-B, A-T, and B-T Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > –P-B spool stroke Spool position at maximum A-T orifice area > –A-T spool stroke Spool position at maximum B-T orifice area < B-T spool stroke
	Orifices A-T and B-T are closed. Orifices P-A and P-B are overlapped. Positive spool position open connections: P-A only Neutral spool position open connections: All closed Negative spool position open connections: P-B only Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke
	Orifices A-T and B-T are open. Orifices P-A and P-B are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: A-T and B-T Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < P-B spool stroke Spool position at maximum A-T orifice area > –A-T spool stroke Spool position at maximum P-B orifice area < B-T spool stroke
	Orifices P-A and A-T are open in the neutral position. Orifices P-B and B-T are overlapped. Positive spool position open connections: P-B and A-T Neutral spool position open connections: P-A and A-T Negative spool position open connections: P-A and B-T Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke Spool position at maximum B-T orifice area < –B-T spool stroke
	Orifice A-T is open in the neutral position. Orifices P-B, A-T, and B-T are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: A-T only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area > –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
	Orifice B-T is open in the neutral position. Orifices P-A, P-B, and A-T are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: B-T only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area < B-T spool stroke
	Orifices P-A and P-B are open. Orifices A-T and B-T are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-A and P-B Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
	Orifice P-A is open in the neutral position. Orifices P-B, A-T, and B-T are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-A only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
	Orifice P-B is open in the neutral position. Orifices P-A, A-T, and B-T are overlapped. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-B only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area > –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
	Orifices P-B and B-T are open in the neutral position. Orifices P-A and A-T are overlapped. Positive spool position open connections: P-B and A-T Neutral spool position open connections: P-B and B-T Negative spool position open connections: P-A and B-T Spool position at maximum P-A orifice area < –P-A spool stroke Spool position at maximum P-B orifice area < P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke Spool position at maximum B-T orifice area > –B-T spool stroke
	Orifices P-A, P-B, A-T, and B-T are closed in the neutral position. P-T is open in the neutral position and closes when the spool displaces. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-T only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke Spool position at maximum P-T orifice area = any value
	Orifice P-A is a constant orifice. Orifices P-B, A-T, and B-T are open in the neutral position. Positive spool position open connections: P-A and P-B Neutral spool position open connections: P-A, P-B, A-T, and B-T Negative spool position open connections: P-A and B-T Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area < P-B spool stroke Spool position at maximum A-T orifice area = any value Spool position at maximum B-T orifice area > –B-T spool stroke
	Orifice P-B is a constant orifice. Orifices P-A, A-T and B-T are open in the neutral position. Positive spool position open connections: P-B and A-T Neutral spool position open connections: P-A, P-B, A-T, and B-T Negative spool position open connections: P-A and P-B Spool position at maximum P-A orifice area > –P-A spool stroke Spool position at maximum A-T orifice area < A-T spool stroke Spool position at maximum B-T orifice area = any value
	Orifice P-A is closed in the neutral position. Ports A and T do not form a flow path. Positive spool position open connections: P-A and P-B Neutral spool position open connections: All closed Negative spool position open connections: P-A and B-T |Spool position at maximum P-A orifice area| > P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum B-T orifice area < –B-T spool stroke
	Orifice P-B is closed in the neutral position. Ports B and T do not form a flow path. Positive spool position open connections: P-B and A-T Neutral spool position open connections: All closed Negative spool position open connections: P-A and P-B Spool position at maximum P-A orifice area < –P-A spool stroke |Spool position at maximum P-B orifice area| > P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke
	Orifice P-A is closed in the neutral position. Orifice A-T is open in the neutral position. Positive spool position open connections: P-A and P-B Neutral spool position open connections: A-T and B-T Negative spool position open connections: P-A and B-T |Spool position at maximum P-A orifice area| > P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area = any value Spool position at maximum B-T orifice area > –B-T spool stroke
	Orifice P-B is closed in the neutral position. Orifice B-T is open in the neutral position. Positive spool position open connections: P-B and A-T Neutral spool position open connections: A-T and B-T Negative spool position open connections: P-A and P-B Spool position at maximum P-A orifice area < –P-A spool stroke |Spool position at maximum P-B orifice area| > P-B spool stroke Spool position at maximum A-T orifice area < A-T spool stroke Spool position at maximum B-T orifice area = any value
	Orifice P-B is closed in the neutral position. Orifice P-T is open in the neutral position. Ports A and T do not form a flow path. Positive spool position open connections: P-A and P-B Neutral spool position open connections: P-T only Negative spool position open connections: P-B and A-T Spool position at maximum P-A orifice area > P-A spool stroke |Spool position at maximum P-B orifice area| > P-B spool stroke Spool position at maximum B-T orifice area < –B-T spool stroke Spool position at maximum P-T orifice area = any value
	Orifice P-A is closed in the neutral position. Orifice P-T is open in the neutral position. Ports A and T do not form a flow path. Positive spool position open connections: P-A and B-T Neutral spool position open connections: P-T only Negative spool position open connections: P-A and P-B |Spool position at maximum P-A orifice area| > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum B-T orifice area > B-T spool stroke Spool position at maximum P-T orifice area = any value

Valve Orifice Parameterizations

The Orifice parameterization parameter sets the model for the open area or volumetric flow rate through one or all of the valve orifices. The block applies the same data for all flow paths if Area characteristics is set to Identical for all flow paths; otherwise, individual parameterizations are applied for the Different for all flow paths setting. You can model valve opening in three ways:

• Linear - area vs. spool travel

  The opening area is a linear function of the spool position received as a signal at port S:

  $$A_{orifice}=\frac{\left(A_{\max }-A_{leak}\right)}{\Delta S_{\max }}\Delta S+A_{leak},$$

  where:

  • ΔS is the spool travel defined in Orifice Definition and Spool Travel Direction.

  • ΔS_max is the Spool travel between closed and open orifice.

  • A_max is the Maximum orifice area.

  • A_leak is the Leakage area.

  

• Tabulated data - Area vs. spool travel

  Provide spool travel vectors for your system or for individual flow paths between ports P, A, B, and T. This data will be used to calculate the relationship between the orifice area and spool displacement. Interpolation is used to determine the opening area between given data points. A_leak and A_max are the first and last parameters of the opening area vector, respectively.

  

• Tabulated data - Volumetric flow rate vs. spool travel and pressure drop

  Provide spool travel and pressure drop vectors and a dependent, 2-D volumetric flow rate array. Interpolation is used to determine flow rate between given data points. The mass flow rate is the product of the volumetric flow rate and the local density.

  

Numerically-Smoothed Valve Area in the Linear Parameterization

When the valve is in a near-open or near-closed position in the linear parameterization, you can maintain numerical robustness in your simulation by adjusting the block Smoothing factor. A smoothing function is applied to all calculated areas, but primarily influences the simulation at the extremes of the valve area.

The normalized valve area is calculated as:

$$\widehat{A}=\frac{\left(A_{orifice}-A_{leak}\right)}{\left(A_{\max }-A_{leak}\right)}.$$

The Smoothing factor, s, is applied to the normalized area:

$${\widehat{A}}_{smoothed}=\frac{1}{2}+\frac{1}{2}\sqrt{{\widehat{A}}_{}^2+{\left(\frac{s}{4}\right)}^2}-\frac{1}{2}\sqrt{{\left(\widehat{A}-1\right)}^2+{\left(\frac{s}{4}\right)}^2}.$$

The smoothed valve area is:

$$A_{smoothed}={\widehat{A}}_{smoothed}\left(A_{\max }-A_{leak}\right)+A_{leak}.$$

Visualize Orifice Openings

To visualize spool offsets and maximum displacement, right-click on the block and select Fluids > Plot Valve Characteristics. The plot shows the orifices selected in the Valve Configuration tab settings. The axes are set by the orifice parameterization selection and are either:

• Orifice Area vs. Spool Position

• Volumetric Flow Rate vs. Spool Position, queried at a specific pressure differential

When the positive, neutral, and negative settings in the Valve Configuration tab feature the same orifice, the orifice opening is displayed as a constant.

Each time you modify the block settings, click Reload Data on the figure window.

The image below shows an example valve configuration. On the Valve Configuration tab:

• Positive spool position open connections is set to P-A and B-T.

• Neutral spool position open connections is set to P-T only.

• Negative spool position open connections is set to P-B and A-T.

On the P-A Orifice tab:

• Spool position at maximum P-A orifice area is set to 2.5e-3 m.

All other spool positions are at the default values.

Example Spool Position Visualization

The visualization shows that the P-A orifice is open between the spool position at -2.53e-3 and 2.53e-3 m. Due to the specification that the P-A orifice is open only when the spool is displaced in the positive direction, the Consistency check for neutral spool and position open connections set to Warning returns:

Warning: P-A orifice must be closed when the spool is in the neutral position. Adjust Spool position at maximum P-A orifice area, Neutral spool position open connections, or Consistency check for neutral spool position open connections. Right-click on the block and select Fluids > Plot Valve Characteristics to view the area or flow of each connection versus spool position.

To resolve this warning, you can:

• Change the Spool position at maximum P-A orifice area to a value larger than 0.005 m.

• Change Consistency check for neutral spool position open connections to None.

• Change the valve configuration by setting Neutral spool position open connections to P-A only.

Faulty Behavior

When faults are enabled, the valve open area becomes stuck at a specified spool position in response to one of these triggers:

• Simulation time — Faulting occurs at a specified time.

• Simulation behavior — Faulting occurs in response to an external trigger. This exposes port Tr.

Four fault options are available in the Spool position when faulted parameter:

• Positive — The spool position freezes in the positive position, opening the Positive spool position open connections flow paths to their maximum value. The flow paths that are only open in the Negative spool position open connections and Neutral spool position open connections are closed.

• Neutral — The spool position freezes in the neutral position, opening all flow paths to their specified values at 0 m.

• Negative — The spool position freezes in the negative position, opening the Negative spool position open connections flow paths to their maximum value. The flow paths that are only open in the Positive spool position open connections and Neutral spool position open connections are closed.

• Maintain last value — The valve freezes at the spool position when the trigger occurs.

Due to numerical smoothing at the extremes of the valve area, in the linear parameterization, the minimum area applied is larger than the Leakage area, and the maximum is smaller than the Maximum orifice area, in proportion to the Smoothing factor value.

Once triggered, the valve remains at the faulted area for the rest of the simulation.

Predefined Parameterization

Pre-parameterized manufacturer data is available for this block. This data allows you to model a specific supplier component.

To load a predefined parameterization,

1. Click the "Select a predefined parameterization" hyperlink in the Fixed-Displacement Motor (IL) block dialog description.

2. Select a part from the drop-down menu and click Update block with selected part.

3. If you change any parameter settings after loading a parameterization, you can check your changes by clicking Compare block settings with selected part. Any difference in settings between the block and pre-defined parameterization will display in the MATLAB command window.

Note

Predefined parameterizations of Simscape components use available data sources for supplying parameter values. Engineering judgement and simplifying assumptions are used to fill in for missing data. As a result, deviations between simulated and actual physical behavior should be expected. To ensure requisite accuracy, you should validate simulated behavior against experimental data and refine component models as necessary.

To learn more, see List of Pre-Parameterized Components.

Ports

Conserving

A — Liquid port

isothermal liquid

Liquid entry or exit port to the valve.

B — Liquid port

isothermal liquid

Liquid entry or exit port to the valve.

P — Liquid port

isothermal liquid

Liquid entry or exit port to the valve.

T — Liquid port

isothermal liquid

Liquid entry or exit port to the valve.

Input

S — Spool displacement, m

physical signal

Spool displacement, in m, specified as a physical signal.

Tr — External fault trigger

physical signal

Physical signal port for an external fault trigger. Triggering occurs when the value is greater than 0.5. There is no unit associated with the trigger value.

Dependencies

This port is visible when Enable faults is set to On and Fault trigger is set to External.

Parameters

Valve Configuration

Positive spool position open connections — Flow paths open when the spool is in a positive position

P-A and B-T (default) | P-A and P-B | P-B and A-T | P-A only | P-B only | P-A, P-B, and A-B

Flow paths open when the spool is in a positive position. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S. The settings for this parameter can be checked against the definitions for the other orifices for consistency when the Consistency check for neutral spool position open connections is set to Warning or Error.

Neutral spool position open connections — Flow paths open when the spool is in the neutral position

All closed (default) | P-A, P-B, A-T, and B-T | A-T and B-T | P-A and A-T | P-A and B-T | P-A and P-B | P-B and A-T | P-B and B-T | A-T only | B-T only | P-A only | P-B only | P-T only | P-A, A-T, and P-T | P-A, P-B, and A-B | P-B, B-T, and P-T | P-A, P-B, A-T, B-T, P-T

Flow paths open when the spool is in the neutral position. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S. The settings for this parameter can be checked against the definitions for the other orifices for consistency when the Consistency check for neutral spool position open connections is set to Warning or Error.

Negative spool position open connections — Flow paths open when the spool moves in the negative direction

P-A and B-T (default) | P-A and P-B | P-B and A-T | P-A only | P-B only | P-A, P-B, and A-B

Flow paths open when the spool moves in the negative direction. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S. The settings for this parameter can be checked against the definitions for the other orifices for consistency when the Consistency check for neutral spool position open connections is set to Warning or Error.

Consistency check for neutral spool position open connections — Whether to check if the orifice settings are consistent with the specified spool position for maximum orifice opening

Warning (default) | Error | None

Whether to check if the neutral spool position open settings on the Valve Configuration tab are consistent with the specified spool position at the maximum orifice area. For each enabled orifice, the actual offset at the spool neutral position should be commensurate with the specified spool offset for each individual orifice.

Model Parameterization

Area characteristics — Flow equations for orifices

Identical for all flow paths (default) | Different for each flow path

Applies uniform or individual flow equations for the valve orifice area. Identical for all flow paths uses the same orifice and spool geometries, flow rates, pressure, and area vectors for all valve orifices. When using Different for each flow path, these parameters are specified individually for each orifice. In both cases, orifices A, B, P, and T have the same cross-sectional areas, discharge coefficients, and Reynolds numbers in the Linear - Area vs. spool travel and Tabulated data - Area vs. spool travel parameterizations. The same Orifice parameterization is applied to all flow paths.

Orifice parameterization — Method of calculating opening area

Linear area vs. spool travel (default) | Tabulated data - Area vs. spool travel | Tabulated data - Volumetric flow rate vs. spool travel and pressure drop

Method of calculating the valve opening area. In the tabulated data parameterizations, you can provide your own valve area and spool travel data for nonlinear valve opening profiles, or you can provide data in terms of volumetric flow rate, spool travel, and pressure drop over the flow path.

Spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Linear - Area vs. spool travel.

Maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of each orifice during the operation of the valve.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Linear - Area vs. spool travel.

Leakage area — Open area when an orifice is fully closed

1e-9 m^2 (default) | positive scalar

Open area when an orifice is fully closed. Any area smaller than this value is maintained at the specified leakage area. This parameter contributes to numerical stability by maintaining continuity in the flow.

Dependencies

To enable this parameter, set Orifice parameterization to Linear - Area vs. spool travel.

Spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the Orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Area vs. spool travel.

Orifice area vector — Vector of valve opening areas

[1e-09, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the Spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Area vs. spool travel.

Spool travel vector, ds — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parametrization of volumetric flow rate. The spool travel vector forms an independent axis with the Pressure drop vector, dp parameter for the 2-D dependent Volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

Pressure drop vector, dp — Vector of valve pressure drop values

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure drop values for the tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the Spool travel vector, ds parameter for the 2-D dependent Volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

Volumetric flow rate table, q(ds,dp) — Array of volumetric flow rates

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; .00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the Spool travel vector, ds parameter.

• N is the number of vector elements in the Pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

Constant orifice area — Orifice area for identical flow paths

1e-4 m^2 (default) | positive scalar

Orifice area when the positive, neutral, and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to either:

• Linear - area vs. spool travel.

• Tabulated data - Area vs. spool travel

The same orifice must be selected in all three of the Valve Configuration parameters:

• Positive spool position open connections

• Neutral spool position open connections

• Negative spool position open connections

Constant orifice pressure drop vector — Vector of pressure differential values for identical flow paths

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

The same orifice must be selected in all three of the Valve Configuration parameters:

• Positive spool position open connections

• Neutral spool position open connections

• Negative spool position open connections

Constant orifice volumetric flow rate vector — Vector of volumetric flow rate values for identical flow paths

[-.0009, .0016, .002, .0024] m^3/s (default) | 1-by-n vector

Vector of volumetric flow rate values for a constant orifice when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

The same orifice must be selected in all three of the Valve Configuration parameters:

• Positive spool position open connections

• Neutral spool position open connections

• Negative spool position open connections

Cross-sectional area at ports P, T, A and B — Area at conserving ports

inf m^2 (default) | positive scalar

Maximum cross-sectional areas at the entry and exit ports P, T, A, and B, which are used in the pressure-flow rate equation that determines the mass flow rate through the valve.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to either:

• Linear - area vs. spool travel

• Tabulated data - Area vs. spool travel

Discharge coefficient — Discharge coefficient

0.64 (default) | positive scalar

Correction factor that accounts for discharge losses in theoretical flows.

Dependencies

To enable this parameter, set Orifice parameterization to either:

• Linear - Area vs. spool travel

• Tabulated data - Area vs. spool travel

Critical Reynolds number — Upper Reynolds number limit for laminar flow

150 (default) | positive scalar

Upper Reynolds number limit for laminar flow through the orifice.

Dependencies

To enable this parameter, set Orifice parameterization to:

• Linear - area vs. spool travel

• Tabulated data - Area vs. spool travel

Smoothing factor — Numerical smoothing factor

0.01 (default) | positive scalar in the range of [0,1]

Continuous smoothing factor that introduces a layer of gradual change based to the flow response when the valve is in near-open and near-closed positions. To increase the stability of your simulation in these regimes, set this parameter to a nonzero value less than one.

Dependencies

To enable this parameter, set Orifice parametrization to Linear - area vs. spool travel.

Pressure recovery — Whether to account for pressure increase in area expansions

Off (default) | On

Whether to account for pressure increase when fluid flows from a region of smaller cross-sectional area to a region of larger cross-sectional area.

Dependencies

To enable this parameter, set Orifice parameterization to:

• Linear - area vs. spool travel

• Tabulated data - Area vs. spool travel

P-A Orifice

Spool position at maximum P-A orifice area — Spool offset for fully open P-A orifice

7.5e-3 m (default) | positive scalar

Spool offset from the neutral position for a fully open P-A orifice. The Consistency check for neutral spool position open connections parameter will notify you if the values set for this spool position are inconsistent or unphysical according to other orifice spool positions. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

• P-A and B-T

• P-A and P-B

• P-A only

Neutral spool position open connections to:

• P-A, P-B, A-T, and B-T

• P-A and A-T

• P-A and B-T

• P-A and P-B

• P-A only

Negative spool position open connections to:

• P-A, P-B, A-T, and B-T

• P-A and A-T

• P-A and B-T

• P-A and P-B

• P-A only

Note:

This parameter is enabled only when the P-A orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.

P-A spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of the P-A orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A orifice spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the P-A orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A orifice area vector — Vector of valve opening areas

[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the P-A spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A orifice spool travel vector, ds — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the P-A orifice pressure drop vector, dp parameter for the 2-D dependent P-A orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A orifice pressure drop vector, dp — Vector of pressure drop values

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure drop values for the tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the P-A orifice spool travel vector, ds parameter for the 2-D dependent P-A orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A orifice volumetric flow rate table, q(ds,dp) — Array of volumetric flow rate values

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; -.00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the P-A orifice spool travel vector, ds parameter.

• N is the number of vector elements in the P-A orifice pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A constant orifice area — Cross-sectional area for a constant orifice

1e-4 m^2 (default) | positive scalar

Orifice area when the positive, neutral, and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to either:

   • Linear - area vs. spool travel

   • Tabulated data - Area vs. spool travel

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A Constant orifice pressure drop vector — Vector of pressure differential values for a constant orifice

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-A Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-A Constant orifice volumetric flow rate vector — Vector of volumetric flow rates for a constant orifice

[-.0009, .0016, .002, .0024] m^3/s (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-A Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-A and A-T

   • P-A and B-T

   • P-A and P-B

   • P-A only

P-B Orifice

Spool position at maximum P-B orifice area — Spool offset from the neutral position for a fully open P-B orifice

7.5e-3 m (default) | positive scalar

Spool offset from the neutral position for a fully open P-B orifice. The Consistency check for neutral spool position open connections parameter will notify you if the values set for this spool position are inconsistent or unphysical according to other orifice spool positions. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

• P-B and A-T

• P-A and P-B

• P-B only

Neutral spool position open connections to:

• P-A, P-B, A-T, and B-T

• P-B and A-T

• P-B and B-T

• P-A and P-B

• P-B only

Negative spool position open connections to:

• P-A, P-B, A-T, and B-T

• P-B and A-T

• P-B and B-T

• P-A and P-B

• P-B only

Note:

This parameter is enabled only when the P-B orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.

P-B spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   or set Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   or set Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of the P-B orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B orifice spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the P-B orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B orifice area vector — Vector of valve opening areas

[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the P-B spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B orifice spool travel vector, ds — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the P-T orifice pressure drop vector, dp parameter for the 2-D dependent P-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only.

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B orifice pressure drop vector, dp — Vector of pressure differential values

[-.1, .3, .5, .7] MPa (default) | 1-byn vector

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the P-B orifice spool travel vector, ds parameter for the 2-D dependent P-B orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B orifice volumetric flow rate table, q(ds,dp) — Array of volumetric flow rate values

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; -.00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the P-B orifice spool travel vector, ds parameter.

• N is the number of vector elements in the P-B orifice pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B constant orifice area — Cross-sectional area for a constant orifice

1e-4 m^2 (default) | positive scalar

Orifice area when the positive, neutral, and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to either:

   • Linear - area vs. spool travel

   • Tabulated data - Area vs. spool travel

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B Constant orifice pressure drop vector — Vector of pressure differential values for a constant orifice

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-B Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

P-B Constant orifice volumetric flow rate vector — Vector of volumetric flow rate values for a constant orifice

[-.0009, .0016, .002, .0024] m^3/s (default) | 1-by-n vector

Vector of volumetric flow rate values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-B Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to:

   • P-B and A-T

   • P-A and P-B

   • P-B only

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

   Negative spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • P-B and B-T

   • P-A and P-B

   • P-B only

A-T Orifice

Spool position at maximum A-T orifice area — Spool offset from the neutral position for a fully open A-T orifice

7.5e-3 m (default) | positive scalar

Spool offset from the neutral position for a fully open A-T orifice. The Consistency check for neutral spool position open connections parameter will notify you if the values set for this spool position are inconsistent or unphysical according to other orifice spool positions. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

• Positive spool position open connections to P-B and A-T.

• Neutral spool position open connections to:

  • P-A, P-B, A-T, and B-T

  • P-B and A-T

  • A-T and B-T

  • P-A and A-T

  • A-T only

• Negative spool position open connections to P-B and A-T.

Note:

This parameter is enabled only when the A-T orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.

A-T spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of the A-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T orifice spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the A-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T orifice area vector — Vector of valve opening areas

[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the A-T spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T orifice spool travel vector, ds — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the A-T orifice pressure drop vector, dp parameter for the 2-D dependent A-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T orifice pressure drop vector, dp — Vector of pressure differential values

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the A-T orifice spool travel vector, ds parameter for the 2-D dependent A-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T orifice volumetric flow rate table, q(ds,dp) — Array of volumetric flow rate values

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; -.00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the A-T orifice spool travel vector, ds parameter.

• N is the number of vector elements in the A-T orifice pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T constant orifice area — Cross-sectional area for a constant orifice

1e-4 m^2 (default) | positive scalar

Orifice area when the positive, neutral, and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to either:

   • Linear - area vs. spool travel

   • Tabulated data - Area vs. spool travel

3. One of the following settings in each parameter:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T Constant orifice pressure drop vector — Vector or pressure differential values for a constant orifice

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the A-T Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

A-T Constant orifice volumetric flow rate vector — Vector of volumetric flow rate values for a constant orifice

[-.0009, .0016, .002, .0024] m^3/s (default) | 1-by-n vector

Vector of volumetric flow rate values when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following settings in each parameter:

   Positive spool position open connections to P-B and A-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • P-B and A-T

   • A-T and B-T

   • P-A and A-T

   • A-T only

   Negative spool position open connections to P-B and A-T.

B-T Orifice

Spool position at maximum B-T orifice area — Spool offset from the neutral position for a fully open B-T orifice

7.5e-3 m (default) | positive scalar

Spool offset from the neutral position for a fully open B-T orifice. The Consistency check for neutral spool position open connections parameter will notify you if the values set for this spool position are inconsistent or unphysical according to other orifice spool positions. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

• Positive spool position open connections to P-A and B-T.

• Neutral spool position open connections to:

  • P-A, P-B, A-T, and B-T

  • A-T and B-T

  • P-A and B-T

  • P-B and B-T

  • B-T only

• Negative spool position open connections to P-A and B-T.

Note:

This parameter is enabled only when the B-T orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.

B-T spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of the B-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T orifice spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the B-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T orifice area vector — Vector of valve opening areas

[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the B-T orifice spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T orifice spool travel vector, ds — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of control member travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the B-T orifice pressure drop vector, dp parameter for the 2-D dependent B-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T orifice pressure drop vector, dp — Vector of pressure differential values

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the B-T orifice spool travel vector, ds parameter for the 2-D dependent B-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T orifice volumetric flow rate table, q(ds,dp) — Array of volumetric flow rate values

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; -.00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the B-T orifice spool travel vector, ds parameter.

• N is the number of vector elements in the B-T orifice pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the following parameters:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T constant orifice area — Cross-sectional orifice area for constant orifices

1e-4 m^2 (default) | positive scalar

Orifice area when the positive, neutral, and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to either:

   • Linear - area vs. spool travel

   • Tabulated data - Area vs. spool travel

3. One of the settings in each parameter:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T Constant orifice pressure drop vector — Vector of pressure differential values for a constant orifice

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the B-T Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the settings in each parameter:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

B-T Constant orifice volumetric flow rate vector — Vector of volumetric flow rates for a constant orifice

[-.0009, .0016, .002, .0024] m^3/s (default) | 1-by-n vector

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the B-T Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

3. One of the settings in each parameter:

   Positive spool position open connections to P-A and B-T.

   Neutral spool position open connections to:

   • P-A, P-B, A-T, and B-T

   • A-T and B-T

   • P-A and B-T

   • P-B and B-T

   • B-T only

   Negative spool position open connections to P-A and B-T.

P-T Orifice

Spool position at maximum P-T orifice area — Spool offset from the neutral position for a fully open P-T orifice

0 m (default) | positive scalar

Spool offset from the neutral position for a fully open P-T orifice. The Consistency check for neutral spool position open connections parameter will notify you if the values set for this spool position are inconsistent or unphysical according to other orifice spool positions. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set Neutral spool position open connections to P-T only.

P-T spool travel between closed and open orifice — Maximum spool stroke

0.005 m (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

P-T maximum orifice area — Maximum orifice opening area

1e-4 m^2 (default) | positive scalar

Largest open area of the P-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Linear - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

P-T orifice spool travel vector — Vector of spool opening distances relative to fully closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of control member travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the P-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

P-T orifice spool travel vector, ds — Vector of spool opening distances relative to fully-closed position

[0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Vector of control member travel distances for the tabular parameterization of volumetric flow rate. The spool travel vector forms an independent axis with the P-T orifice pressure drop vector, dp parameter for the 2-D dependent P-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

P-T orifice pressure drop vector, dp — Vector of pressure differential values

[-.1, .3, .5, .7] MPa (default) | 1-by-n vector

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the P-T orifice spool travel vector, ds parameter for the 2-D dependent P-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

P-T orifice volumetric flow rate table, q(ds,dp) — Array of volumetric flow rates

[-1e-08, 2.2e-08, 2.8e-08, 3.4e-08; -9e-06, .00015, .0002, .00024; -.00036, .00063, .00081, .00096; -.00054, .00094, .0012, .0014; -.00091, .0016, .002, .0024] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

• M is the number of vector elements in the P-T orifice spool travel vector, ds parameter.

• N is the number of vector elements in the P-T orifice pressure drop vector, dp parameter.

Dependencies

To enable this parameter, set:

1. Area characteristics to Different for each flow path.

2. Orifice parameterization to Tabulated data - Area vs. spool travel.

3. Neutral spool position open connections to P-T only.

Faults

Enable faults — Fault option

Off (default) | On

Enable externally or temporally triggered faults. When faulting occurs, the valve area normally set by the opening parameterization will be set to the value specified in the Spool position area when faulted parameter.

Spool position when faulted — Set faulted characteristics

Positive (default) | Neutral | Negative | Maintain last value

Sets the faulted valve spool position. You can choose for the valve to seize when the spool is in the positive position, negative position, or at the position when faulting is triggered.

Dependencies

To enable this parameter, set Enable faults to On.

Fault trigger — External or temporal trigger option

Temporal (default) | External

Whether a fault trigger occurs due to an external event or at a specified time.

When set to External, port Tr is enabled. A physical signal at port Tr that is greater than 0.5 triggers faulting.

When set to Temporal, when the Simulation time for fault event is reached, the valve area will be set to the value specified in the Spool position when faulted parameter.

Dependencies

To enable this parameter, set Enable faults to On.

Simulation time for fault event — Time at which faulting is triggered

5 s (default) | positive scalar

When the Simulation time for fault event is reached, the valve area is set to the value specified in the Spool position when faulted parameter.

Dependencies

To enable this parameter, set Enable faults to On and Fault trigger to Temporal.

Model Examples

4-Way 3-Position Valve Parameterization

Parameterize and test a 4-way 3-position valve with a test harness. A plot script is provided with the example for comparing output flow between the block and data to verify the test harness. A live script is also provided with this example to explain the parameterization and the test harness workflow in detail.

Open Model

Hydraulic Flow Rectifier Circuit

A flow rectifier circuit with four check valves and a flow control valve. It is used to allow a single flow control valve to control fluid flow in both directions. Similar to a Graetz circuit implemented with diodes, the check valves are arranged in such a way that flow always passes through the flow control valve in the same direction. In the Orifices subsystem, there are two more check valves that are used to select the orifice that the flow passes through depending on the flow direction.

Open Model

Hydraulic Actuator with Dual Counterbalance Valves

An actuator controlled by a 4-way directional valve and loaded with an overriding load, requiring the use of counterbalance valves to prevent the load from creeping when the directional valve is in the neutral position. In the neutral position, the directional valve connects ports A and B to the reservoir while blocking the pressure port P. The counterbalance valves block flow from returning to the reservoir, thus holding the actuator in place.

Open Model

Version History

Introduced in R2020a