Solving Common Sensor Application

Problems

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Before We Start

Moderator Presenters

Randy FrankDesign World

Dr. Rolf Weber

IR Products, OSRAM Opto

Semiconductors

Mike StanleyFreescale

Semiconductor

John Gammel

Sensor products, Silicon Labs

www.silabs.com

Temperature and Humidity SensingApplication Issues and Solutions

Dr. John C. GammelMay 29, 2014

6

Common applications for relative humidity (RH) and temperature sensors

Overview of Silicon Labs’ RH and temperature sensors

Temperature effect on humidity

Solder sensitivity

Dust and liquid protection

Dealing with multiple devices on the I2C bus

Development tools

Agenda

7

Humidity Sensor Applications

Remote Monitoring

• Windshield Defogging

• Automobile Climate Control

• Manufacturing Environmental Monitoring

• Compressed Air Systems

• Asset Tracking

• Food and Pharmaceutical Storage

• Telecom Cabinets and Datacenters

• Cellular Base Stations

• HVAC/R Thermostats and Smoke Alarms

• Consumer Weather Stations

• Wireless Sensor Nodes

• Cellular Phone and Accessories

• Respiratory Therapy

• CPAP Machines

• Ventilators

Remote MonitoringHome Automation

and Consumer Devices

Automotive and Industrial

EquipmentHealthcare

8

• Negligible BOM cost• Small 3x3 mm size• SMT compatible• Highest reliability• Filter cover protects

against contamination

• High cost• Large size• Not SMT-compatible• Low reliability• Risk of

contamination

• Large BOM• User calibration• Not SMT-compatible• Low reliability• Risk of contamination

Si70xx vs. Legacy RH & Temperature Sensor Solutions

Manufacturing Cost and Complexity

Discretes (R/C)

MCMs and Hybrid Modules

Si701x/2x Monolithic ICs

Si701x/2x RH & temperature sensors reduce cost and complexity, and improve

ease of use vs. legacy solutions

Time

9

Introducing Si701x/2x Relative Humidity Sensors

High-precision relative humidity & temperature sensors offer unmatched ease of use

Accurate sensing Full factory calibration and internal compensation +/-3% RH / ±0.4°C max accuracy

Industry’s lowest power consumption 2.2 µW @ 3.3 V, 8-bit, 1 sample/second

Si701x/2x feature set provides unmatched ease of use Unique, optional low-profile protective cover Industry-standard PCB footprint and software interface Support for 2-zone temperature sensor (Si7013)

Standard CMOS fab process ensures high-volume production capacity and high reliability

10

Si701x/2x RH Sensor Family Overview

Higher accuracy and lower power than Silicon Labs’ first-generation Si7005 sensor

Extended -40 to +125 °C temperature range

AEC-Q100 automotive qualified

Optional cover/filter available for all devices

Shown withoptional Cover/Filter

Part No.(s) PackageTypical

AccuracyMax

AccuracyFeatures

Si7013

3 x 3 mmDFN-10

±2% RH±0.3°C

±3% RH±0.4°C

High precision RH and 2-zone temperature sensor with I2C interface

Si7021

3 x 3 mmDFN-6

±2% RH±0.3°C

±3% RH±0.4°C

High precision RH/T sensor with I2C interface. Industry-standard PCB footprint and software interface

Si7020

3 x 3 mmDFN-6

±3% RH±0.3°C

±4% RH±0.4°C

Compact RH/T sensor with I2C interface. Industry-standard PCB footprint and software interface

11

The “rule of thumb” for how temperature affects humidity is at 100% humidity 1°C of heating will reduce humidity by 5%

This decreases linearly to zero as RH reduces

For accurate reading of humidity level the sensor mustbe placed well away from any heat sources

If the amount of heating is known, it is possible to compensate A thermistor near the heat source can be used to determine the

amount of heating and aid in the compensation The Si7013 two-zone temperature sensor can be used to digitize

and linearize the thermistor voltage

In some applications, such as window fog sensingdew point is of more interest than relative humidity Dew point is the temperature at which condensation occurs for a given

air temperature and relative humidity Dew point is not affected by heating

Temperature Effect on Relative Humidity

1 °C

5%RH

12

Many IC type sensors are susceptible to shift in readings in soldering

This is particularly true for all humidity sensors (not just Silicon Labs) Solder flux can contaminate the sensor Excessive heat will cause shifts in readings

The optional protective cover for Si7013/20/21sensors is solder compatible and providesprotection against contaminates duringsoldering as well as after soldering

Use industry standard solder reflow profile 260 °C maximum

Do not use solder flux and use “no clean solder” Cleaning in an ultrasonic alcohol bath will contaminate the sensor

Do no use hot air rework tools directed at the sensor

Limit solder touch up or hand soldering to 5 seconds per lead

Rework with new parts

Solder Sensitivity

13

All humidity sensors are sensitive to dust and liquids and must be protected

A membrane that will allow water vapor to pass but will block liquids and dust is recommended

Generally, these type of membranes are made of expanded Polytetrafluoroethylene (ePTFE) and are available from several manufacturers Polytetrafluoroethylene is known by the brand name Teflon The best know type of ePTFE is Gore-Tex

The ePTFE cover available for Si7013/20/21 sensors issolder compatible and factory applied IP67 for dust and moisture resistance Blocks liquid water to 2.7bar (39 PSI) Oleophobicity (oil resistance) rating of 7

ePTFE barriers do not protect against chemical vapors Use low volatile organic compounds (VOC) for other materials used in PCB assembly such as

under fill and conformal coating Avoid cleaning agents such as alcohol or ammonia

Dust and Liquid Protection

Optional Cover/Filter

14

The Si7013/20/21 family and many other standard sensors have the option of “no hold” or “hold” mode commands Hold mode commands are more convenient because the device will hold the I2C bus (clock held low)

until the conversion is complete This avoids having to set a timer or poll for conversion complete, but it does hold the bus for the

conversion time (typically 10 msec) If the no-hold command is used, then the bus is not held and the device will not ACK until data is ready

Most sensors have a fixed I2C address so you cannot put more than one device of the same type on the bus Some RH sensors such as the Si7013 have a pin-programmed address For larger numbers of devices of the same type, switch the I2C bus The I2C bus is bidirectional on both SDA and SCL so a digital gate generally will not work; in this case

use an analog switch If no hold mode commands are used and care is taken not to use a high-bus speed, clock stretching is

avoided and SCL can be digitally switched In either case, be careful to leave SCL high when the device is not addressed

Multiple Devices on the I2C bus

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Si701x/2x EVBs and Development Kits

Si7013USB-DONGLE• USB Dongle with Si7013• “Postage stamp” boards for

Si7013, Si7020, Si7021

Si7013EVB-UDPSi7013EVB-UDP-F960 (8-bit)Si7013EVB-UDP-M3L1 (32-bit)• UDP port header card• 8-bit MCU development kit• 32-bit MCU development kit

P/N Description

Si7013USB-DONGLEGeneral-purpose evaluation platform for “plug and measure” evaluation of Si7013, Si7020 and

Si7021

SENSOR-EXP-EVB Sensor expansion card for EFM32 Zero Gecko MCU Starter Kit

Si7013EVB-UDP UDP port header card for Silicon Labs MCU development boards

Si7013EVB-UDP-F960 (8-bit)Si7013EVB-UDP-M3L1 (32-bit)

Si7013 UDP port header card + MCU development kit

Si701x/2x General-Purpose EVB

SENSOR-EXP-EVB• Sensor expansion card for

Zero Gecko MCU Starter Kit

16

Si701x/2x Collateral and Software

Collateral Si7013, Si7020 and Si7021 data sheets AN607: Si70xx Humidity Sensor Designer’s Guide

Software For Si7013USB-DONGLE:

• Evaluation software GUI• USB drivers and source code

For Si7013EVB-UDP and MCU development kits:• Demonstration software and source code• Data logger application, GUI and source code

Android driver and demonstration app Linux driver (Lm-sensors framework)

All Si701x/2x collateral and software is available athttp://www.silabs.com/products/sensors/humidity-sensors/

www.silabs.com

www.silabs.com/sensors

External Use

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Layered Intelligence and the Internet of ThingsDesign World Web Event

M a y 2 0 1 4

Michael StanleyManager, Algorithm DevelopmentFreescale Sensor Solutions Division

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External Use | 19

Freescale SemiconductorSensors Solutions Division - Market Focus

Safe & Efficient AutomobilesSafe driving, front/side impact

Tire information system

Active driver assistance

Passenger occupancy detection

Industrial Sensor NetworksConnected intelligence

Fault monitoring/prognostication

High precision modules

Extreme Portable ElectronicsLow profile packages

Low power consumption

Submersible sensors

Automotive

Consumer

• Standalone sensing systems• Ruggedized packages• Wide sensing ranges

• Accelerometer• Gyroscope• Pressure• Magnetometer• MCU integrated sensors

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Topics• Condition-Based Maintenance (CBM)• Condition-Based Monitoring• Prognostics and Health Management (PHM) systems• Machine Monitoring• Predictive Maintenance

All mean essentially the same thing, which forms the basis for a • mature industry, that was• doing IoT before there was an IoT

Lowered costs in sensors and communications imply that CBM techniques may be poised to extend into new areas – IF we can simplify the software side of things.

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figure source; http://en.wikipedia.org/wiki/File:Centrifugal_Pump-mod.jpg

This machine includes:• rotating motor• centrifugal pump• linkage between the two

Each is subject to its own array of problems. These might include:• Bearing failures• load imbalance• shaft misalignment• looseness• gearbox faults• drive belts• resonance

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TangentialAxial

Radial

Aligned

Angular misalignment causes axial vibration at1X running frequency

Parallel misalignment causes radial vibration at2X running frequency

Shaft Misalignment

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Pd

Bd

Pd = pitch diameterBd = ball diameterNb = number of ballsS = speed (revolutions/sec = contact angleBSF = Ball Spin FrequencyBPFO = Ball Pass Frequency of Outer TraceBPFI = Ball Pass Frequency of Inner Trace

Bearing faults have specific frequency signatures

Defect signals may be swamped by other noise in the system, in which case enveloping or wavelet techniques may be used to extract the signature.

For ball defects:

BSF = ½ (Pd/Bd) x S x [1 – (Bd/Pd x cos)2]

For outer trace defects:

BPFO = ½ Nb x S x [1 – (Bd/Pd x cos)]

For inner trace defects:

BPFI = ½ Nb x S x [1 + (Bd/Pd x cos)]

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http://commons.wikimedia.org/wiki/File:NonSynchronousGearBoxSF.jpg

gear mesh speed = shaft speed X # of teeth

So = Si X Ti/To

where:Ti = number of input teethTo = number of output teethSi = input speedSo = output speed

Gears also have specific frequency signatures

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Courtesy of Volvo Construction Equipment (mages.volvoce.com)

Credit: IBM Research (http://www-03.ibm.com/press/uk/en/photo/43250.wss)

Predictive maintenance is a must when you cannot afford downtime.

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CBM Breakdown

Condition based maintenance

diagnostics prognosticswhat went wrong? includes estimation for remaining useful life

data driven

physics-based

require sufficient samples that were run to failure

must understand the physics of expected failure progression and how to get parameters required for the model

more mature than prognostics

statistical

machine learning

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Maintenance Scenarios

maintenancepreparation

actualmaintenance

scheduledmaintenance

maintenancepreparation

continuous RUL estimation

Fault DetectionDown Time

Down Time

Unscheduled Maintenance

Managed Maintenance

From “Major Challenges in Prognostics: Study on Benchmarking Prognostics Datasets” by Eker, Camci and Jennions

Notice that in the 2nd scenario, we can minimize inventory and do prep work while still “line-up”

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• General Electric• Techenomics International• Vibrotech reliability services• Condition Monitoring Services Inc.• Vikon• STI Vibration Monitoring• ALS Limited• Fluke• GeoSonics / Vibra-Tech• Timken• Vipac Engineers and Scientists Ltd.• Wagner Equipment Co.• KIM Gruppen• Allied Reliability Group• Tezzco Inc.• Sterling SIHI BmbH

• Bentley Nevada Services• Monition Limited• ROZH• GasTOPS Ltd.• Critical Software• Azima DLI• Balmac Inc.• Diagnostic Solutions• Siemens• Prosig• Condition Analyzing Corporation• Metso Corporation• Dresser-Rand• dB Prűftechnik• KCF technologies• Schenck USA• Machine Monitoring Systems

There are lots of players in this field. Many are service companies.

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ISO 13374 Provides a Standard Architecture for Condition Monitoring & Diagnostics

Sensor / Transducer / Manual Entry

Data Acquisition (DA)

Data Manipulation (DM)

State Detection (SD)

Health Assessment (HA)

Prognostic Assessment (PA)

Advisory Generation (AG)

External systems,

data archiving and block configurati

on

Technical

displays and

information

presentation

DA Basically a “server of calibrated digitized sensor data records”. Outputs include digitized data, timestamps, data quality indicators

DM Extracts features from digitized sensor data. Examples: FFT, wavelet, virtual sensor, filtered data, normalized data, etc.

SD Compares DA & DM outputs against expected baselines / operational limits to determine health indicators. Outputs might include enumerated state values, threshold alerts, rate of change alerts, deviation severities, etc.

HA Determine the current health of the system and diagnose fault conditions

PA Estimate remaining useful lifePredict faults / failuresGenerate recommendations

AG Integrate outputs from all other blocks and provide optimized recommendations, courses of action, advisories, prioritized operational & maintenance actions, etc.

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Freescale is developing collateral designed to simplify implementation of condition monitoring systems.

Data Acquisition (DA)

Data Manipulation (DM)

State Detection (SD)

Health Assessment (HA)

Prognostic Assessment (PA)

Advisory Generation (AG)

Sensor / Transducer / Manual Entry

Development Board Matlab

Choices include: • Sensor Type• Axis (X, Y, Z, temp, etc)• Sample Rate

Feature Extraction choices include:• FFT• Wavelets• Entropy• RMS noise• peak value• etc.

Use Freescale supplied GUIs and embedded apps to experiment with data capture and feature selection, then utilize Matlab machine learning algorithms to develop higher level ISO 13374 functions.

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In real time, the user can change:• Sensor• Axis• Window• Filter

All FFT computations are done on the sensor board.

Data can be logged, replayed, and transferred to Matlab.

A similar tool for Wavelet analysis is in development.

Freescale Xtrinsic Vibration Monitoring

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ToLearnMore

Organizations:• Open Operations &

Maintenance Initiative (http://www.openoandm.org )

• Machinery Information Management Open System Alliance (http://www.mimosa.org)

• International Organization for Standardization (http://www.iso.org)

• Center for Intelligent Maintenance Systems (http://www.imscenter.net)

References:

1. “Commercialization of Prognostics Systems Leveraging Commercial Off-The Shelf Instrumentation, Analysis and Data Base Technologies”, Preston Johnson

2. “Vibration Diagnostic Guide”, SKF Reliability Systems

3. “Harris Shock and Vibration Handbook”, 6th edition, Allan G. Piersol & Thomas L. Paez, McGraw Hill

4. “A Review of PHM System’s Architectural Frameworks”, Surya Kunch, Chaochao Chen & Michael Pecht.

5. “Review of Vibration Analysis Methods for Gearbox Diagnostics and Prognostics”, Mitchell Lebold, et. al.

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© 2014 Freescale Semiconductor, Inc. | External Use

www.Freescale.com

Matchbox Demo:Intelligent Proximity

Sensing

Why a packaged demo?

Challenges for proximity sensing:

Cross talk due to reflection from a cover glass

=> Demo with cover glass and light barrier is

more realistic

Cross talk

PCB top view

SFH 7770 E6: 3 prox. channels and ALS

SFH 4059 LEDs

Externally switched SFH 4059S LEDfor long range

SFH 7743 for application selection

IR LEDsProximity sensing for consumer devices:

Small LEDs are essential

SFH 4640 / 4641 / 4441 SFH 4645 / 4646 / 4140 SFH 4046 SFH 4045N

Application Modes

Proximity sensing (1”, 4” & 6”)

Place / remove hand

Application Modes

Slide

Slide left / right for LED on.

Slide right / left for LED off.

Application ModesRotary

Rotate finger clockwise to increase brightness.

Counter-clockwise will reduce brightness

Application ModesTouch

Tap for LED on / off.

Hold finger to increase / reduce brightness

Application ModesWave

Wave left / right for LED on.

Wave a second time for LED off.

Application Modes

0.00

20.00

40.00

60.00

80.00

100.00

120.00

0 50 100 150

Re

lati

ve

sig

na

l str

en

gth

Time in ms

Proximity signals 2 ms apart

Prox 1

Prox 2

• Two pulses 2 ms apart:• One measurement every 10 ms• Centroid time = Σ time * signal / Σ signal• Prox 1: 61.16 ms• Prox 2: 59.64 ms => Prox 2 before Prox 1

Application Modes

Ambient Light Sensor

Ambient light will increase brightness

Graphical User Interface

Demo Kit ContentSensor demo with Micro USB jack

3 x AAA batteries

Battery pack with Micro USB connector

USB cable

Getting Started • Use the battery pack or USB cable to power the

demo.1a. Battery Pack

• Insert AAA batteries in the battery pack

• Connect the battery pack to the demo

• Switch on battery pack

2. Operating the demo

1b. USB Cable

• Connect the USB cable to demo and a computer

• See: Software Installation and Graphical User Interface

Indicator LED layouts and respective hand motions

SoftwareDownload and installation of the GUI and USB driver:• http://ledlight.osram-os.com/matchboxdemo

Source code:• LabVIEW VI available on request

• Demo board C Code available on request

• Contact: rolf.weber@osram-os.com

Questions?Randy FrankDesign Worldr.frank@ieee.org

Dr. Rolf WeberIR Products, OSRAM Opto SemiconductorsRolf.Weber@osram-os.com

Mike StanleyFreescale SemiconductorMike.Stanley@freescale.com

John GammelSensor products, Silicon Labsjohn.gammel@silabs.com

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