As background, pressure sensors are electronic transducers which measure the pressure of a fluid and convert said measurement into one or more corresponding electrical output signals. The one or more electrical output signals produced by the pressure sensor may comprise, inter alia, an analog voltage (e.g., 0 to 10 Volts), an analog current (e.g., 4 to 20 mA), one or more bus system signals (e.g., CANopen or HART protocol), or a wireless signal (e.g., ZigBee, Bluetooth, or WirelessHART). Other types of electrical output signals may be produced as well, as is known in the art.
Pressure sensors may comprise one or more half bridges which may be used to measure the pressure of the fluid. In one embodiment, a pressure sensor may comprise two half bridges. A half bridge may comprise two resistors mechanically coupled to the fluid. The resistance value of each resistor of the half bridge may change when the pressure of the fluid changes. Such a resistor may be called resistive pressure sensing element, or RPSE for short. The pressure sensor may measure the resistance of each RSPE in the one or more half bridges in order to determine the pressure of the fluid.
In some pressure sensor applications, it may be possible for at least one of the RSPEs of the one or more half bridges to malfunction. Such malfunctions may occur, for example, due to excessive vibration, extreme shock, or operation of the pressure sensor outside its permitted operating parameters. In these cases, prior art pressure sensors may not be capable of measuring the pressure of the fluid and may fail to produce an electrical output signal corresponding to the pressure of the fluid. The embodiments described herein include apparatuses and methods to permit a pressure sensor to produce an electrical output signal corresponding to the pressure of the fluid, even if one or more of its RSPEs malfunction.
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