Absolute Pressure & Temperature Sensor (MA)
Measurement of pressure and temperature in wet air networks.
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Description
The Pressure & Temperature Sensor (MA) unit is an ideal sensor that measures pressure and temperature in a wet air network. There is no mass or energy flow through the sensor.
The sensor contains an implicit reference node, which means that only the A port is required for absolute pressure or temperature measurements as well as overpressure.
Port B is used if you want to measure the difference in pressure or temperature between two nodes in the model. Measurements are positive when the values on port A are greater than the values on port B.
Temperature measurements are different from pressure measurements because the rate of energy flow depends on the direction of flow. A temperature measurement represents the temperature upstream of the node being measured. For example, if port A of the Pressure & Temperature Sensor (MA) unit is connected to a node between pipe 1 and pipe 2 and moist air flows from pipe 1 to pipe 2, the temperature measured at port A represents the temperature of the volume of moist air in pipe 1. If the air flow then reverses direction and flows from pipe 2 into pipe 1, the temperature measured at port A is the temperature of the moist air volume in pipe 2. If the temperatures of the two volumes of moist air are different, the measured temperature changes when the direction of flow changes. If two or more streams merge at a node, the temperature measurement at the node represents a weighted average based on perfect mixing of the merging stream.
Four signal ports are available for outputting measurement data:
-
Pa - absolute pressure.
-
Pg - overpressure.
-
P - pressure difference.
-
T - temperature.
Ports
Non-directional
A - sensor input
`humid air
Humid air port, corresponds to the sensor input.
B - sensor output
`humid air
Humid air port, corresponds to the sensor output. Measurements are positive when the values on port A are greater than the values on port B.
Dependencies
To use this port, set the Measurement reference to `Difference'.
Output
Pa - pressure, Pa
scalar
Signal output port. Outputs the result of absolute pressure measurement.
Dependencies
To use this port, set the Measurement reference to Absolute, select the Pressure checkbox, and set the Pressure type to Absolute pressure.
Pg is the pressure, Pa
scalar
Signal output port. Outputs the result of gauge pressure measurement.
Dependencies
To use this port, set the Measurement reference to `Absolute', select the Pressure checkbox, and set the Pressure type to `Gauge pressure'.
P is the pressure, Pa
scalar
Signal output port. Outputs the result of pressure difference measurement.
Dependencies
To use this port, set the Measurement reference to `Difference' and select the Pressure checkbox.
T - temperature, K
scalar
Signal output port. Outputs the result of temperature measurement.
Dependencies
To use this port, select the Temperature checkbox.
Parameters
Measurement reference - the way the pressure is measured
Absolute (by default) | Difference
Sets the pressure measurement method:
-
Absolute- the sensor measures pressure and temperature on port A. The sensor contains an implicit reference node, which means that only port A is needed for pressure or temperature measurements. -
Difference- the sensor measures the difference in pressure or temperature between two nodes in the model. When this option is selected, port B is displayed on the block icon.
Pressure - Enable or disable the output port for pressure measurement
On (By default) | Off
Checking this box enables the Pa, Pg or P output port to measure pressure.
Pressure type - the type of pressure to be measured
Absolute pressure (by default) | Gauge pressure.
Select whether the sensor is measuring absolute pressure or gauge pressure:
-
Absolute pressure- the sensor measures absolute pressure at port A. When this option is selected, the Pa port is displayed on the unit icon. -
Gauge pressure- the sensor measures the gauge pressure at port A. When this parameter is selected, the Pg port is displayed on the unit icon.
Dependencies
To use this parameter, set the Measurement reference parameter to Absolute and select the Pressure checkbox.
Temperature - Enable or disable the temperature measurement output port
On (By default) | `Off
When this checkbox is selected, the T output port for temperature measurement is enabled.