2MPPDPS传感器

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Important Factors in Applying Pressure Sensors

•Pressure reference

–Absolute: pressure is measured relative to vacuum (0kPa)

–Relative: pressure is measured relative to ambient atmospheric pressure (101.3kPa)

–Sealed Gage: pressure is measured relative to a fixed pressure sealed inside the sensor (for APT, fixed pressure is ~40kPa)

–Differential: measures pressure difference between 2 pressure lines

•Hermetic means nooringseals in pressure media. Required by some regulations, recommended for some fluids.

•Case isolation often required in electrically noisy environments, such as inverter-driven compressor or pump systems. Keeps inverter electrical noise out of the pressure signal.

•I/O Formats

–Ratiometric: output voltage is proportional to power supply voltage. Typical for most Sensata products

–Vreg: output voltage is fixed at 0 to 5Vdcor 0 to 10Vdcindependent of power supply. Power supply typically 24Vdcor 32Vdcand requires a voltage regulator in the sensor.

–4-20mA: output signal is proportional to current from 4mAto 20mA. Power supply typically 8 to 32Vdc.

–LIN and SENT are digital communications designed for automotive

How is OFM positioned compared to APT or MSG?

•OFM is designed to fill 2 gaps in Sensata’s portfolio:

–Hermetic sensing in 10 to 70 bar range

–Case isolated to 1800Vacand 10 MΩat 500Vdc

•In higher pressure ranges >50 bar, MSG offers a lower cost hermetic solution, but lacks case isolation. Limitation is glass bond between port and gages.

•In lower pressure ranges <50 bar, 45CP offers a lower cost case isolated solution but requires an o-ring seal (not hermetic).

•OFM accuracy slightly better than APT with Gen3 ASIC

–OFMCpk= 1.9 to +/-1.5%fs spec from -40 to 125 C

–APTCpk= 1.8 to +/-2.0%fs spec from -20 to 125 C (see EL10002927)

•APT is available in sealed gage, relative, and absolute versions.

•MSG are always relative sensors. At high pressure ranges the difference between a relative and absolute sensor are small (change in reference pressure at 1000 m is 12kPa, or 0.1% of 10 bar).

•OFM is only available in an absolute pressure reference version.

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