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參數(shù)資料
| 型號： | MPX5006 |
| 廠商： | Motorola, Inc. |
| 英文描述： | Pressure Sensor(壓力傳感器) |
| 中文描述： | 壓力傳感器（壓力傳感器） |
| 文件頁數(shù)： | 1/4頁 |
| 文件大小： | 65K |
| 代理商： | MPX5006 |
1
Motorola, Inc. 1998
Prepared by Ador Reodique
Motorola Sensor Systems and Applications Engineering
INTRODUCTION
This application note describes how to implement an auto–
zero function when using a Motorola integrated pressure sen-
sor with a microcontroller and an analog to digital converter
(MCU and an A/D). Auto–zero is a compensation technique
based on sampling the offset of the sensor at reference pres-
sure (atmospheric pressure is a zero reference for a gauge
measurement) in order to correct the sensor output for long–
term offset drift or variation.
Sources of offset errors are due to device to device offset vari-
ation (trim errors), mechanical stresses (mounting stresses),
shifts due to temperature and aging. Performing auto–zero will
greatly reduce these errors. The amount of error correction is
limited by the resolution of the A/D.
In pressure sensing applications where a zero–pressure
reference condition can exist, auto–zero can be implemented
easily when an integrated pressure sensor is interfaced to
an MCU.
EFFECTS OF OFFSET ERRORS
Figure 1 illustrates the transfer function of an integrated
pressure sensor. It is expressed by the linear function:
VOUT= VOFF + [(VFSO
VOFF)/(PMAX
= VOFF + S*P.
Here, VOUT is the voltage output of the sensor, VFSO is the
full–scale output, VOFF is the offset, PMAX is the maximum
pressure and PREF s the reference pressure. Note that (VFSO
VOFF/PMAX PREF) can be hought of as he slope of he ine
and VOFF as they y–intercept. The slope is also referred to as
the sensitivity, S, of the sensor.
PREF)]*P
Figure 1. Definition of Span, Full–Scale Output,
Offset and Sensitivity
SENSOR OUTPUT
VFSO
VOFF
PREF
PMAX
PRESSURE
SPAN
S
A two–point pressure calibration can be performed to
accurately determine the sensitivity and get rid of the offset
calibration errors altogether. However, this can be very
expensive in a high volume production due to extra time and
labor involved. The system designer therefore designs a
pressure sensor system by relying on the sensitivity and offset
data given in the data sheet and using a linear equation to
determine the pressure. Using the later, the sensed pressure
is easily determined by:
P = (VOUT
If an offset error is introduced due to device to device varia-
tion, mechanical stresses, or offset shift due to temperature
(the offset has a temperature coefficient or TCO), those errors
will show up as an error,
P, in the pressure reading:
P +
P = [VOUT
(VOFF +
VOFF)]/S.
As evident in Figure 2, offset errors,
VOFF, have the effect
of moving the intercept up and down withoutaffecting the
sensitivity. We can therefore correct this error by sampling the
pressure at zero reference pressure (atmosphere) and
subtracting this from the sensor output.
VOFF)/S.
Figure 2. Effect of Offset Errors
SENSOR OUTPUT VOUT
VFSO
VOFF
PREF(atm
PMAX
PRESSURE
VOFF
VP
P
P
AUTO–ZERO CONSIDERATIONS
IN APPLICATIONS
There is an important consideration when implementing
auto–zero. In order to use this technique, a zero pressure
reference condition must be known to exist in the system.
Order this document
by AN1636/D
SEMICONDUCTOR APPLICATION NOTE
REV 1
相關(guān)PDF資料 |
PDF描述 |
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| MPX5050GVSX | OPERATING OVERVIEW INTEGRATED PRESSURE SENSOR 0 to 50 kPa (0 to 7.25 psi) 0.2 to 4.7 Volts Output |
| MPX5050GP1 | Sensor |
| MPX5050GVP | OPERATING OVERVIEW INTEGRATED PRESSURE SENSOR 0 to 50 kPa (0 to 7.25 psi) 0.2 to 4.7 Volts Output |
| MPX5050GVS | OPERATING OVERVIEW INTEGRATED PRESSURE SENSOR 0 to 50 kPa (0 to 7.25 psi) 0.2 to 4.7 Volts Output |
| MPX5050GSX | OPERATING OVERVIEW INTEGRATED PRESSURE SENSOR 0 to 50 kPa (0 to 7.25 psi) 0.2 to 4.7 Volts Output |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MPX5010 | 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:Integrated Silicon Pressure Sensor On-Chip Signal Conditioned, Temperature Compensated and Calibrated |
| MPX5010_09 | 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:Integrated Silicon Pressure Sensor On-Chip Signal Conditioned, Temperature Compensated and Calibrated |
| MPX5010D | 功能描述:板上安裝壓力/力傳感器 PRES SEN INTEG 10KPA RoHS:否 制造商:Honeywell 工作壓力:0 bar to 4 bar 壓力類型:Gage 準確性:+ / - 0.25 % 輸出類型:Digital 安裝風格:Through Hole 工作電源電壓:5 V 封裝 / 箱體:SIP 端口類型:Dual Radial Barbed, Same sides |
| MPX5010D | 制造商:Freescale Semiconductor 功能描述:Pressure Sensors IC |
| MPX5010DP | 功能描述:板上安裝壓力/力傳感器 PRES SEN INTEG 10KPA RoHS:否 制造商:Honeywell 工作壓力:0 bar to 4 bar 壓力類型:Gage 準確性:+ / - 0.25 % 輸出類型:Digital 安裝風格:Through Hole 工作電源電壓:5 V 封裝 / 箱體:SIP 端口類型:Dual Radial Barbed, Same sides |
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