Key Factors in Selec0ng a Pressure Sensor DAVID EZEKIEL OWNER, VICE PRESIDENT SERVOFLO CORPORATION

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1 Key Factors in Selec0ng a Pressure Sensor DAVID EZEKIEL OWNER, VICE PRESIDENT SERVOFLO CORPORATION

2 APPLICATION EXAMPLES OF HOW WE WORK** Blood Pressure VAV Control Cleanrooms Barometers Breathalyzers Infusion Pumps 28 Years of Applica0on Support Logis0cs & Stocking Water Level DVT Machines Filter Blockage Transducers Vacuum Measurement ** many more not listed

3 PRESSURE SENSORS TODAY BROAD CATEGORY OF SENSORS Board level (for clean air) Ceramic sensors & elements for harsh media, wide temperatures and/or liquids (stainless steel/oil-filled) Stainless steel for capacitive, low pressure Fully packaged transducers COTS (common off-the-shelf) to modified to customized

4 PAST VERSUS PRESENT ADVENT OF MEMS TECHNOLOGY HAS CREATED: Smaller sensors More robust (mechanical) Lower cost Lower power supply Higher accuracy Lower pressure ranges Better offset stability Increased design options (mechanical design & electrical outputs) WHICH COMES FIRST? THE CHICKEN...

5 THE RESULT OR THE EGG? EVERYTHING IS MEASURABLE Medical (including disposable) HVAC Barometric Instrumentation (industrial) Consumer (low cost, high volume) Other environmental factors relative humidity, temperature, O2 & other gases

6 THE RESULT IS THE PARADOX OF CHOICE A HUGE RANGE OF MANUFACTURERS & PRODUCTS TO CHOOSE FROM MANY MODELS WITH DIFFERENT FEATURES, ACCURACIES, PACKAGES

7 KNOW YOUR ORGANIZATION & PRODUCT NEEDS WHAT SYSTEM PERFORMANCE DO I NEED? HOW QUICKLY WILL WE START SELLING PRODUCT? WHAT SKILLS DO YOU HAVE IN YOUR ORGANIZATION? (DESIGN, MANUFACTURING, SYSTEM INTEGRATION, CALIBRATION) HOW MANY SOURCES DO YOU NEED? WHAT IS THE ROLE OF CONTRACT MANUFACTURING? Turnkey Board assembly only

8 IDENTIFY YOUR SPOT ON THE PRICE/PERFORMANCE SPECTRUM Amplified (digital) Price Amplified (analog) Unamplified Uncalibrated Uncompensated Die Modified Low End Special Performance (accuracy)

9 WHERE DO I START? LET S FOCUS ON THESE KEY FACTORS Application Basics Mechanical Electrical Assembly WHAT IS MOST IMPORTANT? ALL FACTORS ARE INTER-RELATED

10 APPLICATION BASICS MEDIA PRESSURE RANGE & TYPE (GAUGE, DIFFERENTIAL, ABSOLUTE) OPERATING TEMPERATURE ACCURACY REQUIRED IN A SPECIFIC TEMPERATURE RANGE POTENTIAL CONTAMINANTS & MOISTURE OVERPRESSURE SYSTEM ACCURACY WHAT CAN BE CONTROLLED BY DESIGN, CALIBRATION, AND FIELD SERVICE? REGULATORY CONSIDERATIONS (UL, FDA, CE, ETC.)

11 MECHANICAL FACTORS SHAPE & SIZE (SMT OR THRU-HOLE) PORT CONFIGURATION & ORIENTATION MECHANICAL CONNECTIONS ROBUSTNESS BURST & OVER PRESSURE

12 ELECTRICAL FACTORS SUPPLY VOLTAGE (3V, 3.3V, 5V, VDC) OUTPUT POWER CONSUMPTION ELECTRICAL CONNECTIONS Low Level Signal mv output Vcc = V BaYery or plug Iout = 4-20 ma Ra0ometric voltage of 0-5V Pressure Sensor Switch Output Non-ra0ometric voltage output Vref = I2C/SPI

13 WHY USE UNAMPLIFIED/UNCALIBRATED OR UNAMPLIFIED CALIBRATED? Uncalibrated, uncompensated & unamplified OWN CALIBRATION PROCESS TREND OVER ACCURACY ON/OFF SINGLE POINT AUTO ZERO POSSIBLE Calibrated, compensated & amplified SIMPLER CALIBRATION ACCURACY IS IMPORTANT WHOLE PRESSURE RANGE IMPORTANT CAN BE USED WITH HIGH RES A/D

14 WHY USE CALIBRATED, COMPENSATED, AMPLIFIED? CUSTOMERS TYPICALLY CANNOT PROVIDE MORE THAN 1 OR 2 CALIBRATION POINTS, ESPECIALLY NOT AT MULTIPLE TEMPERATURES COMPONENT SELECTION BASED ON PRICE/PERFORMANCE TARGETS MODIFICATION & CUSTOMIZATION POSSIBLE GOAL: MINIMIZE SPACE USAGE, COMPONENT COUNT AND LABOR CONTENT COST PREMIUM IS MINIMAL ANALOG OR DIGITAL OUTPUTS

15 COMPENSATED, CALIBRATED & AMPLIFIED THINGS TO CONSIDER: RESOLUTION, RESPONSE TIME, ACCURACY ADC/DAC COULD MEAN LOSS OF RESOLUTION

16 ACCURACY FACTORS RESOLUTION & RESPONSE TIME ACCURACY OVER TEMPERATURE OVERALL SYSTEM ACCURACY REQUIRED CAN ACCURACY/PERFORMANCE BE CUSTOMIZED? YES! ACCURACY OVER A DEFINED PRESSURE RANGE & OPERATING ENVIRONMENT

17 EVALUATING DIFFERENT SENSOR MANUFACTURERS CURRENT TRENDS SOME CONSOLIDATION OF MANUFACTURERS MANY OPTIONS TO CHOOSE FROM SOURCES ARE ALL OVER THE WORLD LEAD-TIMES OFTEN LONG. HOW TO MAKE SURE YOU CAN GET PARTS WHEN YOU NEED THEM? PRICE TECHNICAL SUPPORT 2 ND SOURCE REQUIREMENTS SOUNDS EASY ON PAPER BUT ARE THERE PIN-TO-PIN REPLACEMENTS? FOCUS ON WHAT THE APPLICATION REQUIRES VERSUS DATASHEET CLAIMS DON T OVERDESIGN FOCUS ON COST OF MEASUREMENT, NOT COST OF COMPONENT

18 IN SUMMARY

19 ABOUT SERVOFLO IN BUSINESS FOR OVER 28 YEARS LOCATED IN LEXINGTON MA PRESSURE SENSORS, ENVIRONMENTAL SENSORS, SENSOR SIGNAL CONDITIONING AND MICROPUMPS OUR SPECIALTY IS HELPING ENGINEERS FIND THE RIGHT SOLUTION AT THE RIGHT PRICE TEL: