Pressure Transducer

Behavioral model of generic pressure transducer that turns pressure measurement into voltage

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Libraries:
Simscape / Electrical / Sensors & Transducers

Description

The Pressure Transducer block models a generic pressure transducer that turns a pressure measurement into a voltage. The block lets you measure pressure in a variety of domains. Specify the domain type using the Fluid port type parameter.

The output voltage is linearly proportional to the pressure, and the block outputs zero volts if the pressure is less than zero. An input pressure equal to the Pressure range parameter value results in an output voltage equal to the Full-scale deflection parameter value. For higher pressures, the output voltage remains at this Full-scale deflection value.

You have three choices of operation mode, which let you select between vacuum, atmospheric pressure, or sealed-gauge reference pressure as the reference point for the pressure measurement.

Optionally, if you set the Dynamics parameter to Model transducer bandwidth, then the dynamics of the sensor are approximated by a first-order lag. The lag is determined by the Bandwidth parameter. If you select this option, you must also specify an initial condition for the lag by using the Measured pressure variable target.

If running your simulation with a fixed-step solver, or generating code for hardware-in-the-loop testing, MathWorks recommends that you set the Dynamics parameter to No dynamics — Suitable for HIL, because this avoids the need for a small simulation time step if the sensor bandwidth is high.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see System Scaling by Nominal Values.

The Measured pressure variable target specifies the initial output for the sensor.

Ports

Conserving

A — Fluid port

Gas | Hydraulic | Thermal Liquid | Moist Air | Two-Phase Fluid

Conserving fluid port for pressure measurement. The port type is defined by the Fluid port type parameter value.

+ — Positive terminal

electrical

Electrical conserving port associated with the positive terminal.

- — Negative terminal

electrical

Electrical conserving port associated with the negative terminal.

Parameters

Fluid port type — Type of fluid port

Gas (default) | Hydraulic | Thermal Liquid | Moist Air | Two-Phase Fluid

Select the fluid port type for pressure measurement:

• Gas (default)

• Hydraulic

• Thermal Liquid

• Moist Air

• Two-Phase Fluid

Pressure range — Maximum pressure

1e6 Pa (default)

Maximum pressure that the sensor can measure, in Pa.

Operation mode — Reference point for pressure measurement

Absolute (default) | Gauge | Sealed-Gauge

Select one of the following options to define the reference point for the pressure measurement:

• Absolute — The pressure measurement is with respect to zero absolute pressure, that is, vacuum. This is the default option.

• Gauge — The pressure measurement is with respect to atmospheric pressure. Atmospheric pressure is defined by the Gas Properties block in the Simscape™ Foundation library.

• Sealed-Gauge — The pressure measurement is referenced to an internal sealed chamber. If you select this option, use the Reference pressure parameter to specify the reference point for pressure measurement.

Reference pressure — Reference pressure

101325 Pa (default)

Reference pressure in the internal sealed chamber.

Dependencies

This parameter is visible only when you select Sealed-Gauge for the Operation mode parameter.

Full-scale deflection — Full-scale deflection

5 V (default)

Output voltage when the measured pressure is equal to, or greater than, the Pressure range parameter value.

Output resistance — Transducer output resistance

200 Ohm (default)

Output resistance of the transducer.

Dynamics — Sensor dynamics option

No dynamics — Suitable for HIL (default) | Model transducer bandwidth

Select one of the following options for modeling sensor dynamics:

• No dynamics — Suitable for HIL — Do not model sensor dynamics. Use this option when running your simulation fixed step or generating code for hardware-in-the-loop testing, because this avoids the need for a small simulation time step if the sensor bandwidth is high. This is the default option.

• Model transducer bandwidth — Model sensor dynamics with a first-order lag approximation, based on the Bandwidth parameter value. You can control the initial condition for the lag by specifying the Measured pressure variable target.

Bandwidth — Bandwidth

5 kHz (default)

Determines the value of the sensor lag.

Dependencies

This parameter is visible only when you select Model transducer bandwidth for the Dynamics parameter.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2012b

R2019a: Fluid Port Type

Prior to R2019a, the Pressure Transducer block had a pneumatic measurement port. Pneumatic blocks are no longer part of the Foundation library, but they are included in the Simscape product installation as an example custom library. The legacy Pressure Transducer block, with a pneumatic port, is now part of this custom library.

From R2019a forward, use the Gas library for modeling pneumatic systems, and use the latest version of the Pressure Transducer block with a gas port.