Xtrinsic Pressure Sensor Introduction - Reports or Presentations

Transcription

TM
April 2013
Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, ColdFire+, CWare, the Energy Efficient Solutions logo, Kinetis, mobileGT, PEG, PowerQUICC, Processor
Expert, QorIQ, Qorivva, StarCore, Symphony and VortiQa are trademarks of Freescale
Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. Airfast, BeeKit, BeeStack, CoreNet, Flexis,
Layerscape, MagniV, MXC, Platform in a Package, QorIQ Qonverge, QUICC Engine, Ready Play,
SafeAssure, the SafeAssure logo, SMARTMOS, Tower, TurboLink, Vybrid and Xtrinsic are
trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of
their respective owners. © 2013 Freescale Semiconductor, Inc.
•
This course will cover Freescale analog and nextgeneration digital pressure sensors.
•
Present applications in industry and medical.
•
Listener will have the opportunity to try on MPL3115
evaluation kit for the altimeter application in mobile
application.
TM
2
Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, ColdFire+, C-Ware, the Energy Efficient Solutions logo, Kinetis, mobileGT, PEG, PowerQUICC,
Processor Expert, QorIQ, Qorivva, StarCore, Symphony and VortiQa are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. Airfast, BeeKit, BeeStack, CoreNet,
Flexis, Layerscape, MagniV, MXC, Platform in a Package, QorIQ Qonverge, QUICC Engine, Ready Play, SafeAssure, the SafeAssure logo, SMARTMOS, Tower, TurboLink, Vybrid and
Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2013 Freescale Semiconductor, Inc.
•
Pressure sensor portfolio
•
Pressure sensor selection
•
Typical applications
•
MPL3115A2 introduction
−
Key messages
−
Target applications
−
Pressure altimetry
−
Collateral and Documentation
TM
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Our Integrated Pressure Sensor (IPS) Technology
Signal
Conditioning
Circuit
Diaphragm
Ion-implanted
Strain Gauge
Single Chip Integrated Silicon Pressure Sensor
TM
4
Output mV
PRT Piezo Resistive Transducer
C
Apply Kirchhoff voltage and current laws:
Rg
R1
VOUT
 R3
R2 
 VIN 


R

R
R

R
G
1
2
 3
VIN
VOUT
B
Change in Resistive Diaphragm leads to Voltage Shift.
D
R3
R2
A
The difference in pressure between P1 and
P2 causes the deflection of diaphragm.
This deflection will be detected by the
piezoresistive strain gauge resistors, located
in the diaphragm, as a mechanical stress,
resulting in a voltage difference.
This voltage difference is processed and
amplified to provide the proper output.
Sensitivity is a primary function of the
dimensional characteristics of the
diaphragm itself, especially its thickness.
Pressure Sensor Cross Section
TM
5
•
P1
Absolute Pressure Sensor
Altimeter / Barometer
Vacuum
Constraint Wafer
Measure an external pressure relative to a zero-pressure reference.
•
P1
Differential Pressure Sensor
Air Flow / Filter Pressure / Pressure Drop
•
Measure the difference between two pressures applied simultaneously.
P2
Gauge Pressure Sensor
P1
Blood Pressure / Water Level / Leak Detection
Measure the pressure relative to atmospheric pressure.
•
P2 = ATM
P1
Vacuum Pressure Sensor
Vacuum Cleaner / Pump
Measure the suction pressure relative to atmospheric pressure.
TM
6
P2 = ATM
Integration
Pressure Sensor Levels of Integration
Temperature
compensation
Amplification
MCU
Output
Amplification
MCU
Output
MPX10DP
BASIC ELEMENT
Altitude: MPXM2102A
MPX2010DP
COMPENSATED
& CALIBRATED
MCU
Altitude:
MPX5010DP
COMPENSATED + CALIBRATED + AMPLIFIED = INTEGRATED
TM
7
Output
MPXA6115A
MPX5100A
MPX4115A
Integration
Design Advantages
Uncompensated:
Compensated
Integrated
Design Considerations
• High sensitivity
• Lowest device cost
• Low-level output allows flexibility
of signal conditioning
• Device to device variation in offset &
span
• Temperature compensation circuitry
required
• Requires Signal conditioning /
amplification of output signal
• Reduced device to device
variations in offset & span
• Reduced temperature drift in
offset & span
• Low-level output allows
flexibility of signal conditioning
• Lower sensitivity due to span
compensation (compared to
uncompensated)
• Priced higher than uncompensated
• Requires signal conditioning /
amplification of output signal
• No amplification needed, direct
interface to MCU
• Signal conditioning, calibration
of span & offset, temperature
compensation included on-chip
• Priced higher than compensated &
uncompensated devices
• Lower piece part count
TM
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Pressure Range
Device
Description
MPX10/12, MPX53
Uncompensated Pressure Sensor series available from 10 to 50kPa
Rated pressure: 10 and 50kPa
MPX2000 series
Compensated Pressure Sensor series available from 10 to 200kPa
Rated pressure: 10, 40, 50, 100 and 200kPa
MPX4000/5000 series
Integrated Pressure Sensor series available from 4 to 1000kPa
MPX4000 series rated pressure: 6, 80, 105, 115 and 250kPa
MPX5000 series rated pressure: 4, 10, 50, 100, 115, 150, 500, 700 and 1000kPa
MPX6000 series
Integrated Pressure Sensors for altimeter, barometer, MAP/BAP applications
Rated pressure: 105, 115, 130, 250, 300 and 400kPa
MPXV7000 Series
Integrated Pressure Sensor for Positive and Negative applications
Rated pressure: ±2, ±7 and ±25kPa
MPL115/3115
Digital Pressure Sensor for Barometer and Altimeter applications
Rated pressure: 115/110kPa
Our pressure sensors are based on a silicon diaphragm and can tolerate a pressure that alternates from positive to negative. It is
important that the applied pressure not rise above the overpressure specification in the positive or negative range.
TM
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Packaging
MPAK
MPAK
Axial Port
Super
Small
Outline
Package
(SSOP)
Case
1317
Tire
Pressure
Monitor
Axial
Port
Side
Port
Dual
Port
Dual
Port
Small
Outline
Package
(SOP)
Case
482
Through
Hole 482B
Medical
Chip Pak
Unibody
Vacuum
Port
Axial
Port
Case
423A
Through
Through
Through
Hole
Hole
Hole
Axial Port Axial Port Axial Port
LGA
MPL115A
MPL3115A
5x3x1.xmm
TM
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Device Numbering System for Pressure Sensors
M PX V 5 010 G C 6 U
CATEGORY
M
Qualified standard
S
Custom device
P,X Prototype device
SHIPPING METHOD
Trays
T1 Tape & Reel
U Tube
PRESSURE SENSORS
SOP LEADFORM
6 Gull wing/Surface mount
7 87 degree/DIP
PACKAGE TYPE
Unibody
A Absolute Small Outline Package (SOP)
C Chip Pak
H Super Small Outline Package (SSOP)
L LGA
M MPAK
V Vented Small Outline Package (SOP)
Z Media Resistant Gel
FAMILY
Uncompensated
2
Compensated
4 - 6 Integrated
7
Integrated, positive/negative pressure
PORTING OPTION
P
Side port Porting
DP
Differential Porting
VP
Vacuum side Porting
C,S
Axial port
RATED PRESSURE
in kPa, except for MPX2300,
expressed in mmHg.
TM
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MEASUREMENT TYPE
A Absolute
D Differential
G Gauge
V Vacuum
Download: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=PRESSURE_SENSORS
TM
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Pressure Sensors
Uncompensated
MPX10/12
10 kPa
D/G
Compensated
Integrated
MPX4000
6, 80, 105, 115, 250 kPa
A/ D /G
MPX2000
10, 40, 50, 100,
200 kPa
A/ D /G /V
MPX53
50 kPa
D/G
MPX5000
4, 10, 50, 100, 115, 150,
500, 700, 1000 kPa
A/ D /G /V
MPX6000
105, 115, 130, 250, 300,
400 kPa
A/ V
MPX7000
±2, ±7, ±25 kPa
D/G
TM
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Digital
MPL115A
50 to 115 kPa
A, SPI / I2C
3 x 5 x 1.2 mm LGA
MPL3115A2
50 to 110 kPa
A, I2C
5 x 3 x 1.1 mm LGA
Measurement Type:
A: Absolute
D: Differential
G: Gauge
V: Vacuum
•
Uncompensated Pressure Sensors: 10 to 50 kPa

−
−
−
•
MPX10/12, MPX53
High sensitivity
Lowest device cost
Low-level output allows flexibility of signal conditioning
Sensing Element
Compensated Pressure Sensors: 10 to 200 kPa

MPX2000 series
−
Reduced device to device variations in offset & span
Reduced temperature drift in offset & span
Low level output allows flexibility in signal conditioning
−
−
TM
14
Sensing Element
+ Temperature
Compensated &
Calibrated
•
Integrated Pressure Sensors (IPS): 2 to 1000 kPa

MPX4000, 5000, 6000, 7000 series
−
No amplification needed, direct interface to MCU
Signal conditioning, calibration of span & offset, temperature
compensation included on-chip
Lower piece part count
−
−
Sensing Element
+ Temperature
Compensated &
Calibrated
+ Signal Conditioning
Integrated Pressure Sensor (IPS) Technology
TM
15

MPL115A: Miniature Digital Barometer
−
50 to 115 kPa absolute pressure
−
10-bit ADC,1 kPa accuracy
−
Digital output options


MPL115A1 for SPI applications

MPL115A2 for I2C applications
MPL3115A2: High Precision Altimeter
−
20/50 – 110 kPa absolute pressure
−
20-bit ADC, less than 1 foot / 0.3 m resolution
−
I2C digital output interface
−
Compensated, direct reading in SI units
TM
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•
•
•
•
−
Key messages
−
Target applications
−
Pressure altimetry
−
TM
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Blood Pressure Monitor Module
MPXM2051 (Measurement)+MPXM2053(Protection)
MPXV5050
CO2 Module
MPXV2010 (Flow measurement)
MPL115A1 (Digital Barometer)
TM
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MPXM2051 key Features:
• Pressure range 0~50kPa
Gauge
• Temperature Compensated
Over 0°C to +85°C
• Linearity: +/- 0.3%
• Full Scale Span: 40 +/1.5mV
• Offset: 0+/- 1.0mV
• Available in Easy-to-Use
Tape & Reel
• Ratiometric to Supply
Voltage
• Gauge Ported
Air Flow Measurement
MPX2010
MPXV7002DP
MPXV5004DP
Barometric Measurement
MPXH6115A
MPL115A
MPL3115A
IPS for Respiratory Device:
• Wide product portfolio for
different pressure range
requirement to cover from
negative to positive pressure.
• Low pressure range family (+/2kPa, 4kPa, 6kPa, 10kPa) offer
design flexibility.
• Easy to implement (no amplifier
needed), ideally suited for
Microprocessor or
Microcontroller-Based Systems
• Barometer to offset altitude
influence
System to support patient breathing during
times of diminished lung capacity.
TM
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Continuous
Positive
Airway
Pressure
(C.P.A.P.)
•
•
Positive Airway Pressure (PAP) is a method
of respiratory ventilation used primarily in the
treatment of sleep apnea.
Barometric measurement is also critical in
some application to avoid altitude deviation.
TM
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Air Pressure Management
System
MPXV5004GC6T1
MPXV7002DP
Barometric Measurement
MPL115A
MPL3115A
In-line measurement Application:
•
Pulse / Pressure measurement.
•
IV Drip counting
Disposable Pressure Sensors
MPX2300DT
Key features:
• Pressure range is from 0 to 300mmHg
• Low cost
• High volume
• Miniature package
• Integrated temperature compensation
and calibration
• Ratiometric to Supply Voltage
• Polysulfone case material (Medical,
Class V Approved)
A standard invasive blood pressure monitoring kits is sterile, single-use kits that relay blood
pressure information from a pressure monitoring catheter to a patient monitoring system.
TM
21
To avoid necrosis of the muscle and
pressure sores ulceration.
Application Needs:
• Gage pressure measurement
• Pressure range <10kpa
• Potential for multiple sensors
• Calibrated / Compensated.
• MCU interface capability.
Pressure Control
MPX5010DP
MPXM2010GS
TM
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Continuous
Enhanced
Circulation
Therapy
(C.E.C.T.)
System
MPX2010
MP3V5010G
MP3V5050G
•
The system provides the optimal hemodynamic profile by applying
intermittent, sequential pressure to the patient’s leg in a systematic
pattern, increasing the peak venous velocity (PVV) of venous blood
flow and reducing the risk of clot formation.
TM
23
Negative
Pressure
Wound
Therapy
(N.P.W.T.)
System
MPL115A
MPL3115A
MPXM2053GS
MPXV5100GC6U
•
Negative Pressure Wound Management, or Closed Wound Suction
(CWS) is a noninvasive treatment by which controlled localized negative
pressure (suction) is delivered to a wide variety of acute, subacute, and
chronic wounds.
TM
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Voltage
Regulatio
n
Bluetooth
Radio
Power
Source
Tilt Sensor
Display
MCU
Position cuff on left
wrist with left thumb
facing upward
Press start button.
Position sensor
detects correct
placement of arm in
relation to the heart.
(Acceleromete
r)
Optional Modules
Keypad
Sensors
Analog
Pressure
Sensor
Once wrist is in the
correct position the
cuff will inflate and take
the measurements.
Motor
Motor
Control
Bleed
Valve
Valve
Control
Peripherals
MCU
Pressure Monitoring
MPXV5050GP
MPXM2053GS
Reading is displayed
on the LCD screen
TM
25
Water/wave
pulsing
Optimal
Cleaning
Cycles
Reduction
of process
time
Smart
Algorithms
Water
consumed
Temp,
Pressure
Accuracy
Efficiency
Water to
Clothing
Ratio
Full
monitoring
of activities
Dirt level of
clothing
Clothing
Absorption
rates
Rate of
water level
change
Leakage
from
system
Warnings/
diagnostics
TM
26
Washing Machine:
• Tub Water Level Monitoring
(up to ~100cm)
• Smart Washer Functions
• Blend Sensing
• Water Conservation
Dishwasher:
• Basin water level monitoring
• Water Filter monitoring
• Countdown to Cycle completion
• Water Conservation
Gauge Pressure Sensor: MPX10/12, MPX2010, MPXV4006G, MPXV5004G, MPXV5010G
TM
27
Calculation:
Atmospheric
pressure
Pressure Sensor
(Atm)
Pout = P1 – Atm
MPVZ4006G
Where:
Tubing
P1 = Plevel + Atm
Tank
Result:
Pout = Plevel
Air Column
(P1)
h = Pout / (r * g)
Water
Level
(Plevel)
r = density
g = gravity constant
h = liquid height
40cmH2O ~ 4kPa
TM
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•
•
•
•
−
Key messages
−
Target applications
−
Pressure altimetry
−
TM
29
Freescale’s Xtrinsic MPL3115A2 provides highly precise pressure / altitude,
temperature data. It has very low-power consumption, smart features and requires
zero data processing for mobile devices, medical and security applications.
Smart Sensor
Unique Performance
 Internal compensation
and conversion
 Autonomous data
acquisition
 Threshold detection
 Min/Max recording
 Offset adjustment
 Programmable events
 20-bit ADC
 Less than 1foot / 0.3m
resolution
 Pressure, altitude and
temperature data
direct reading
 Flexible sampling rate
up to 128x
Extended Battery Life
 The pressure sensor
operates at 8.5 µA in
low-power mode at 1
Hz.
 The 32 sample FIFO
offloads
communications with
the host processor.
The Smart Choice for Precise Pressure and Altitude Detection
TM
30
•
Absolute pressure range: 20 to 110 kPa
•
Pressure relative accuracy: ±0.05 kPa
•
Resolution: 1.5 Pa / 0.3 m
•
Operating temperature range: -40 to 85 ̊C
•
Supply voltage:1.95 to 3.6 V
•
I/O interface supply: 1.62 to 3.6 V
•
Low current consumption:
•
−
Standby mode: 2µA
−
Low-power mode: 8.5µA @ 1Hz sampling
Datasheet
Compensated, direct reading
−
20-bit pressure measurement in Pascal
−
20-bit altitude measurement in meter
−
12-bit temperature measurement in degree C
•
IIC digital output interface (operates up to 400 kHz)
•
2 programmable interrupt pins for auto-wake, min/max and threshold detection
•
Embedded 32 sample FIFO buffer
•
Low-profile 3 X 5 X 1.1 mm LGA package
TM
31

Atmospheric pressure measurement

Temperature measurement

Weather Barometry using MPL3115A2
Changes of 3kPa to 7kPa drops in pressure signal bad
weather (Storms/Cyclone)
Water vapor in the air drops pressure as humidity makes air
LIGHTER.
High Pressure areas next to Low Pressure areas will lead to
lots of Wind.
Sudden pressure drops also signal a tornado for example.
Clear skies/weather is seen by higher pressure or an
increase of 3kPa.





AN3914 – Modern Altimeter and Barometer System
TM
32
Weather Station






Used in electric motor speed-regulating system
Running power automatic regulation
Ambient and suction pressure measurement
Filter monitor
Noise reducing
High Efficiency & Energy Saving

The MPL3115A2 can be used in vacuum cleaner by implementing
AUTO ZERO.

At the end of operation, the atmospheric pressure should be
measured and stored in memory.

At the beginning of the next cycle, the suction pressure created by
the electric motor with the fan can be monitored to ensure the air
filter is allowing adequate suction pressure.

Pressure inside canister is equal to ambient pressure when
Vacuum is OFF.
TM
33
Vacuum
Cleaner

Pressure measurement

Temperature measurement

The MPL3115A2 provides not only pressure measurement, but it
has a functional temperature sensor that with calibration can
provide temperature +/ 1 ºC.

High value and perishable shipments can be monitored for
pressure and temperature throughout shipping cycle. Hazardous
material surcharges from dry ice can be eliminated.

By monitoring pressure, high value shipments can be pressurized
to ensure the shipment has not been tampered with. Real-time
pressure profiling provides history.
Package
Tracking
TM
34

Altitude measurement

Constant Oxygen flow rate maintenance

The MPL3115A2 digital pressure sensor essentially
determines the altitude the patient is at.

Higher altitudes demand higher oxygen levels, while lower
altitudes will need less.

Air is thinner at higher altitude. In order to maintain the same
amount of Oxygen going to a patient, flow rate has to be
increased in a ventilator.

MPL3115A2 is used in ventilator to automatically maintain
constant Oxygen flow rate at all altitudes.

This conserves oxygen and energy in ventilator systems.
Respiratory Device
TM
35

Ambient pressure measurement
 Suction pressure measurement

The MPL3115A2 is used in a differential pressure
application.
 The pump must maintain 40kPa of suction
pressure below ambient pressure.
 This ensures fluids are drawn from the wound and
that a seal is maintained with the bandage.
Atmospheric Pressure
P0 at about 101 kPa
BANDAGE
MPL3115A as
barometric sensor
PUMP
Negative Pressure
Wound Management
PCB
Wound
Suction Pressure about
40 kPa below Po
MPL3115A as
vacuum sensor
TM
36

Altitude measurement

GPS signals cannot penetrate buildings,
Altimeter can be re-zeroed using GPS derived
location information when signal is lost.

Altimeter provides floor information for GPS
backup, e911 or location based services, 0.3m
resolution enables building level certainty.

Low power and low host CPU overhead

Fast: 1m resolution reading >5Hz rate
GPS and Cellular
Phones
TM
37
Fishing Barometer
Pedometer
Sport Bicycle
Sport Watch
Flying Saucer
Aeromodelling
TM
38
Altimeter
Barometer
Function
•
•
•
•
−
Key messages
−
Target applications
−
Pressure altimetry
−
TM
39
AN4528_Pressure Altimetry
Introduce
•
Altimeter is used to measure the altitude of an abject
above a fixed level. It can provide level information
for GPS assist, e911 or location based services.
•
Pressure altimetry is one of the most common
solutions, and uses the absolute pressure sensor to
determine the altitude by comparing atmospheric
pressure to sea level pressure, and then this sensor
is named Pressure Altimeter.
•
MPL3115A2 is a precision pressure altimeter with
0.3m resolution enables building level certainty,
including mezzanine (1/2 level). It has very low-power
consumption, smart features and requires zero data
processing for mobile devices, medical and security
applications.
TM
40
Altitude (m)
Conversion
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
-1000
P  P0  (1 
h
)5.255876
44330.77


P
h  44330.77  1  ( )0.190263 
P0


20
30
40
50 60 70 80
Pressure (kPa)
g0 M
L0  h R * L0
P  P0  (1
)
T0
90 100 110
Where:
P0 = 101325 Pa
Sea level standard atmospheric pressure
L0 = 0.0065 K/m
Temperature lapse rate from sea level to 11 km
T0 = 288.15 K
Sea level standard temperature
g0 = 9.80665 m/s2
Sea level gravitational acceleration
M = 0.0289644 kg/mol
Mean molecular weight of air
*
R = 8.31432 N·m/(K·mol)
Universal gas constant
TM
41
Measurement Range
Operational
Range
12000
20, 11775
Altitude (m)
10000
8000
Calibrated
Range
6000
50, 5574
4000
2000
101.325, 0
0
110, -698
-2000
20
30
40
50
60
70
80
90
100
110
Atmospheric Pressure (kPa)
The measurement range of MPL3115A2 can cover all areas on the land:
• Mount Everest
the highest point on earth
8848m
• Leadville
the highest city in US
3094m
• Sea Level
0m
• Dead Sea
the lowest point on earth
-422m
TM
42
31.44kPa
69.28kPa
101.3kPa
106.5kPa
Relative Measurement Method
•
In short distance/interval applications to improve the measurement accuracy.
•
Resolution is the minimum change what can be reliably measured.
Pressure Reading (kPa)
Relative Measurement
110
Relative
measurement error
Offset
Ideal Straight Line
Absolute Accuracy Limit
h1 = h1real + hoffset
h2 = h2real + hoffset
Δh = h2 – h1
= h2real – h1real
Absolute Pressure
Reading
Relative Pressure
Reading
Relative Error Band
50
50
110
Pressure Applied (kPa)
Notes:
•
The measurement error becomes smaller with the measurement range reducing with the offset removing.
•
The minimum relative measurement error will depend on the resolution of the sensor.
•
MPL3115A2 provides a stable 30 cm output resolution in altitude.
TM
43
Altitude (m)
•
•
•
•
The atmosphere is a chaotic system. And U.S. Standard
Atmosphere is based on many of the assumptions.
The altitude of one point is the height above zero meters at sea
level. But sea level is not a constant over the surface of the Earth.
The sea level pressure is defined as 101.325 kPa. But the actual
sea level pressure in world is not same, and is always changed
with weather variations.
Weather is the state of the atmosphere. Atmospheric pressure,
temperature and moisture will be changed with weather variations.
Uncertainty and variations will cause the errors in altitude
measurement.
0
…
•
100000
Outer Space
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
-1000
20
50
101.325
Troposphere
(average depth is about 17 km in the middle latitudes)
Effect in Applications
110
Pressure (kPa)
TM
44
Outer Space
•
Errors caused by sea level pressure changes
1.
obtain the actual sea level pressure (P0)

Weather reports on radio, television, newspapers or on the internet.

Worked out by the pressure (P) measured at a given altitude (h).
2.
h
) 5.255876
44330.77
Input P0 into BAR_IN register for internal altitude calculation.

Sea level shift is looked as sea level pressure change.
P0  P  (1 
Barometric Pressure Input Register:
BAR_IN_MSB (0x14)，BAR_IN_LSB (0x15)
•
Input is equivalent sea level pressure for
measurement location.
•
Value is input in 2 Pa units.
•
Unsigned 16-bit integers.
•
The default value is 101,326 Pa.
TM
45
Outer Space
•
Temperature Effect
−
Altitude
The altitude algorithm provides the basic solution with temperature lapse rate (L0) and sea level
standard temperature (T0) introduced, enables the dynamic altitude detection below 11 km.
−
Weather
MPL3115A2 performs temperature compensation internally with inside temperature sensor. Also
the temperature offset can be compensated by OFF_T registers.
−
Other devices
Provide a smooth air path between the sensor and atmosphere to reduce the temperature effect
from the other running devices around the sensor.
Temperature Data User Offset register:
OFF_T (0x2C)
•
8-bit 2's complement
•
Range is from -8 to +7.9 °C
•
0.0625 °C per LSB.
TM
46
Outer Space
•
Others
1.
Atmospheric pressure changes caused by humidity and suspended particles;
2.
Air condition on/off cycling, breeze and zero altitude shift;
3.
Room pressure dynamic changes with doors opening and closing;
4.
Light on the Sensor Die can increase the reading. PN junction

Need laminar flow to minimizes above pressure issues;

Utilizing OFF_H register to adjust the altitude offset value;

Implementing relative measurement method to reduce or
even remove the effects.
Altitude Data User Offset Register:
OFF_H (0x2D)
•
8-bit 2’s complement
•
Range is from -128 to +127 meters
•
in meters
TM
47
AN4519_MPL3115_Reference Code
Typical Communication Exchange
Vdd
100nF 10μF
1
8
2
7
3
6
4
5
SCL
SCL
MCU
SDA
(IIC Master)
INT
SDA
100nF
MPL3115A2
EN
INT1
INT2
(IIC Slave)
Interrupt
Master sends the following commands
Slave responds by executing command or outputting Data
Write Altitude measure request (1Byte)
MPL3115A2 interrupt when measurement complete
Read Altitude and Temperature (5 Bytes)
MPL3115A2 returns compensated converted Altitude and
Temperature Data
TM
48
AN4519_MPL3115_Reference Code
FIFO
Write Altitude FIFO operation request (2Bytes)
MPL3115A2 interrupt when 32 measurements complete
Read 32 Altitude, Temperature (160 Bytes)
MPL3115A2 returns compensated converted Altitude and
Temperature Data
Integrated Alarm
MPL3115A2 interrupt when programmed altitude exceed
given range
MPL3115A2 interrupt when programmed temperature
exceed given range
MPL3115A2 interrupt when programmed pressure exceed
given range
TM
49
Reference Code
20-bit pressure reading with altitude calculation:
PressCnt = ((U32)OUT_P_MSB<<24|(U32)OUT_P_CSB<<16|(U32)OUT_P_LSB<<8)>>12;
PressCntdec = (float)PressCnt/4;
//Pressure in Pa, 4=2^2
AltCntdec = 44330.77*(1-pow(PressCntdec/101325, 0.1902632))+(S8)IIC_RegRead(OFF_H_REG);
20-bit altitude reading with pressure calculation:
AltCnt = ((S32)OUT_P_MSB<<24|(S32)OUT_P_CSB<<16|(S32)OUT_P_LSB<<8)>>12;
AltCntdec = (float)AltCnt/16;
//Altitude in meter, 16=2^4
PressCntdec = 101325*pow((1-AltCntdec/44330.77), 5.255876)+(S8)IIC_RegRead(OFF_P_REG)*4;
12-bit temperature reading:
TempCnt = ((S16)OUT_T_MSB<<8|(S16)OUT_T_LSB)>>4;
TempCntdec = (float)TempCnt/16;
//Temperature in degree C, 16=2^4
Notes: The value in the user offset data register will be added to the result internally, and no need additional calculation.
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50
Floor Test Chart
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51
•
•
•
•
−
Key messages
−
Target applications
−
Pressure altimetry
−
TM
52
•
Data Sheet, Fact Sheet
•
Application Notes:



•
AN4519: reference code
AN4481: Sensor I2C Setup and FAQ
AN4528: Pressure Altimetry using the MPL3115A2
Development tools



KITSTBMPL3115A2
MPL3115A2 development board
DEMOSTBMPL3115A2
MPL3115A2 sensor toolbox kit
MPL3115A2 Sensor Toolbox User’s Guide
•
Android Driver
•
YouTube video
http://www.youtube.com/watch?v=LzrhZu3X3L4&feature=relmfu
http://www.youtube.com/watch?v=NgZCwXJDH7s&feature=relmfu
•
Websites: http://www.freescale.com/pressure
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53
•
Sensor Toolbox Kit (KITSTBMPL3115A2) $75
−
−
−
−
•
Includes a self identifying MPL3115A2 pressure sensor
development board
Works with the USB communication board
Includes Sensor Toolbox demo and evaluation
software
Will be available at: www.freescale.com/sensortoolbox
Sensor Toolbox Bundle
(DEMOSTBMPL3115A2) $99
−
−
This Sensor Toolbox kit comes with the MPL3115A2
pressure sensor development board and the USB
board
Will be available at: www.freescale.com/sensortoolbox
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54
•
Freescale provides uncompensated, compensated and
integrated pressure sensors, also digital pressure sensors to
meet absolute, differential, gauge and vacuum pressure
measurements.
•
Freescale pressure sensors are widely used in medical,
appliance, industrial and consumer applications.
•
Freescale’s Xtrinsic MPL3115A2 has been ready for high
accuracy altimeter and barometer application.
•
Question???
TM
55
•
Sensors
−
www.freescale.com/sensors
−
http://www.freescale.com/sensingplatform
− http://www.freescale.com/sensordata
−
•
www.freescale.com/mems
Sensor Products
−
www.freescale.com/xyz
− www.freescale.com/magnetic
− www.freescale.com/pressure
−
•
http://www.freescale.com/sensortoolbox
Blogs: Smart Sensors
−
http://blogs.freescale.com/2011/06/06/location-based-services-sensors-go-beyond-thenavigation/?tid=NL_2311
−
http://blogs.freescale.com/author/michaelestanley/

What in the World is Contextual Sensing?

Evolving intelligence with sensors

Magnetic sensor makes electronic compass design easy
TM
56
TM

Xtrinsic Pressure Sensor Introduction - Reports or Presentations

Transcription

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