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.
本产的工定制是是，牌是森塔，型号是45CP，种类是电学，料是金属，料物理性质是体，料晶体结构是非晶，制作工艺是集成，输出信号是数字型