LEADS/EMS ADVANCED CAL/SPAN INTERPRETATION

8 - 1 IPS MeteoStarFebruary 22, 2007

LEADS/EMSLEADS/EMS

ADVANCEDADVANCEDCAL/SPANCAL/SPAN

INTERPRETATIONINTERPRETATION


• Review All Of The Automated Tests That Are Conducted On Calibrations And Span Checks

• Develop An Understanding Of What Each Of These Tests Means

• Review The Tools Available To You For Troubleshooting

– Accomplished Through Case Studies

– Web Pages

– Manual Validation

– Zeno Operator Interface

WHAT WE HOPE TO ACCOMPLISH


• Automatic Quality Control Are Normally Augmented By Quarterly Manual Span Source Audits

• Span Source Audits Evaluate The Accuracy Of The Station Calibrator

• Corrective Action Is Required If Audit Limits Are Exceeded

• If The Audit Passes, Then The Pollutant Monitor Should Be Adjusted To Agree With The M-level Concentration Produced By The Station Calibrator

• This Sets The Slope Of The Monitor’s Response To The Ideal

• If A Slope Test Warning Is Reported Thereafter, Then Action Must Be Taken To Determine If The Error Was Caused By Monitor Drift Or Span Source Drift

• A Span Source Audit May Be Needed If There Are No Obvious Instrument Problems

SPAN SOURCE AUDITS


• There Are Several Types Of Quality Checks

• Calibration Sequences Are Run Periodically Or When Equipment Is Changed To Establish A New Slope And Intercept

• Span Check Sequences Are Run Weekly To Ascertain Whether Or Not A Particular Instrument Is Drifting Or Haywire - May Also Set A New Intercept

• Span-Zero Sequences Can Be Run Nightly To Catch Instrument Drift

• Any Of These Sequences Can Be Automatically Scheduled On Either The Calibrator Or The Data Logger

• Any Of These Sequences Can Be Manually Initiated As Necessary

QUALITY CHECKS


• Sequences Are Composed Of Levels

• A Level Consists Of A Set Concentration From The Station Calibrator Introduced Into A Monitor For A Set Number Of 5-Minute Sample Periods

• Each Level Is Assigned A Letter Code (M, R, S, T, Or G) By The Datalogger -- These Correspond To Various Percentages Of The Instrument Full-Scale

• A Set Number Of 5-Minute Samples (Usually 3) In Each Level Are Allowed For Instrument Stabilization

• The Remaining Samples (Usually 4) Are Processed By LEADS.

CALIBRATION SEQUENCES


• During Calibrations– Completeness

– Monitor Voltage and Concentration Outlier Checks

– Concentration Spacing Check

– Slope/Intercept Checks

– Zero/Span Checks

– Precision/Linearity Check

– Converter Efficiency Checks (NOx & H2S)

– Scrubber Efficiency Checks (H2S)

• During Span Checks– Completeness

– Monitor Voltage and Concentration Outlier Checks

– Concentration Spacing Check

– Zero/Span Checks

– Linearity Check

– Converter Efficiency Checks (NOx & H2S)

– Scrubber Efficiency Checks (H2S)

LEADS QC CHECKS


• All QC Tests Performed On Calibration Or Span Check Data Have Both Warning And Failure Limits Except The Outlier Tests

• Each Outlier Test Uses Only One Limit But The Test Is Repeated If An Outlier Is Detected.

• Each Warning Limit Is Chosen Statistically To Represent The 3rd Standard Deviation Value About The Mean Error Of A Test

• There Should Be Only A 0.27% Probability Of Exceeding A Warning Limit If The Monitoring System Is Working Properly

• DO NOT IGNORE WARNINGS

TEST LIMITS


• Each Failure Limit Is Chosen To Be At Least 1.5 Times The Warning Limit And Is Intended To Represent The Maximum Error That Will Be Tolerated Without Invalidation Of The Affected Data

• Ideal Values For Each Of The Tests Are Listed In The Calibration And Span Check Reports Available From The CAMS Status Report Web Pages.

• The Limits Can Also Be Seen On The Cal Limits Web Page

• For Each Test, The Ideal Value Is Subtracted From The Measured Value To Obtain The Test Error. This Error Is Then Compared To The Warning And Failure Limits.

TEST LIMITS (Cont.)


• Automatic Invalidation Of Data Is Based Only On Whether A QC Test Passes Or Fails

• Warnings Are Not Considered In This Processing

• Failure Of A Concentration Outlier Test Or A Concentration Spacing Test Indicates A Problem With The Calibration System But Not With The Monitor (Except NO2)

• The Calibration Or Span Check Event Involved Is Considered Invalid And The Ambient Pollution Data Is Unaffected

DATA VALIDATION RULES


AUTOMATIC CALIBRATION TESTS

Back ForwardCompleteness Incomplete N/A N/AVoltage Outlier Failed Yes YesConcentration Outlier Invalid N/A N/AConcentration Spacing Invalid N/A N/ASlope Failed No YesIntercept Failed No YesPrecision Failed Yes YesZero Failed Yes NoSpan Failed Yes NoNOx Balance Test Failed Yes YesNOx Converter Eff. Test Failed Yes YesH2S Converter Eff. Test Failed Yes YesH2s Scrubber Eff. Test Failed Yes Yes

RejectTest Failure


AUTOMATIC SPAN TESTS

Back ForwardCompleteness Incomplete N/A N/AVoltage Outlier Failed Yes YesConcentration Outlier Invalid N/A N/AConcentration Spacing Invalid N/A N/AZero Failed Yes YesSpan Failed Yes YesLinearity Failed Yes YesNOx Balance Test Failed Yes YesNOx Converter Eff. Test Failed Yes YesH2S Converter Eff. Test Failed Yes YesH2S Scrubber Eff. Test Failed Yes Yes

RejectTest Failure


• Incomplete

– The Data Did Not Arrive In The Proper Sequence Or There Were Either Too Few Or Too Many Samples At Each Level

• Invalid

– The Calibrator Did Not Deliver The Challenge Gas At Correctly Spaced Intervals

• Failed

– One Or More Of The Automatic QC Checks Exceeded A Pre-Set Failure Limit -- Data Is Automatically Rejected Accordingly

• Warning

– One Or More Of The Automatic QC Checks Exceeded A Pre-Set Warning Limit -- The Calibration Or Span Check Is Still Valid And Is Still Used

• Passed

– All Automatic QC Checks Were Passed

POSSIBLE QC CHECK FLAGS


Level

M*

R

S

T*

G*

Conc. (ppm)

0.4, CO 40

0.3, CO 30

0.2, CO 20

0.09, CO 9

0.0

* Note - Levels used during Span Checks

O3, SO2, AND CO CAL SEQUENCE


NO2 Conc. (ppm)

0

0

0.4

0

0.3

0

0.2

0

0.09

NOx Conc. (ppm)

0

0.47

0.47

0.37

0.37

0.27

0.27

0.16

0.16

Level

G*

M*

M†*

R

R†

S

S†

T*

T†*

NO Conc. (ppm)

0

0.47

0.07

0.37

0.07

0.27

0.07

0.16

0.07

*Note - Levels used during Span Checks†Note - Gas Phase Titration Levels

NO, NO2, AND NOX CAL SEQUENCE


Scrubber Bypassed

No

No

No

No

Yes

No

No

SO2 Conc. (ppm)

0

0

0

0

0.09

0.09

0

Level

M*

R

S

T*

T1*

T2*

G*

H2S Conc. (ppm)

0.4

0.3

0.2

0.09

0

0

0

*Note - Levels used during Span ChecksT1 - H2S Converter Efficiency CheckT2 - SO2 Scrubber Efficiency Check

H2S CAL SEQUENCE


• Performed On Both Calibrations And Span Checks

• Tests To See That Data Arrives In Correct Order And The Correct Number Of Updates For Each Level Are Present

• Possible Failure Modes:

– Data Received Out Of Order» Comms Processing Problem - Can Generally Be Recovered By Reloading Data

– Missing Data During A Cal Or Span» Power Outage - No Can Do» Comms Processing Problem - Can Generally Be Recovered By Reloading Data » Zeno Time Flagging - Can Generally Be Recovered By Reloading Data

– Too Many Update Steps For A Given Level– Cals/Spans Started Without Capturing Valid Data Between Them

• Trip To Station Not Always Necessary

COMPLETENESS TEST


VOLTAGE OUTLIER


• Tests Are Based On The Measured Voltages From The Instrument

• Tests To See That No Single Voltage Measurement For A Level Is More Than An Allowed Deviation From The Average Voltage


– Low Source Air Pressure– Empty Gas Bottle– Zeno Incorrectly Translating Voltage In To Voltage Out– Incorrect Analog Span Adjustment On Instrument– Moisture In Lines

• You Must Go To The Station And Check The Equipment


CONCENTRATION OUTLIER


• Tests To See That No Single Concentration Measurement For A Level Is More Than An Allowed Deviation From The Average Concentration

• This Test Was Specifically Designed To Catch Calibration System Problems


– Calibration System Problems» Low Source Air Pressure» Empty Gas Bottle» Ozone Generator Problem

– Instrument Span Set Incorrectly– Other Instrument Problem– Moisture In Lines



NO2 CONCENTRATION OUTLIER


• Based Entirely On NO Channel Performance On Previous Non-Titration Level (M-Level) And Current Titration Level (M*-Level) -- NO2 Voltages Are Not Part Of This Test

• Tests To See That No Single Concentration Measurement For A Level Is More Than An Allowed Deviation From The Average Concentration


– O3 Concentration Unstable– NO Concentration Unstable– Other Instrument Problem– Leak In Line– Moisture In Lines



NO2 CONCENTRATION CALCULATIONS

NO Voltages And Concentrations NO2 Concentrations

5924

85924470429


CONCENTRATION SPACING


• Tests To See That The Calibrator Is Delivering Evenly Spaced Concentrations Throughout The Instrument’s Range

• No Concentration For A Level Can Be More Than An Allowed Deviation From The Ideal Concentration


– Bad Source Air Supply» Generally Shows Up With T-Level Too High

– Bad Ozone Generator Inside Calibrator» Generally Shows Up With T-Level Too Low

– Empty Gas Bottle– Moisture In Lines



NO2 CONCENTRATION SPACING


• Based Entirely On NO Channel Performance On Previous Non-Titration Level (M-Level) And Current Titration Level (M*-Level) -- Differs From Normal Concentration Spacing Test

• No Concentration For A Level Can Be More Than An Allowed Deviation From The Ideal Concentration


– Calibration Of O3 Generator Does Not Agree With NO Calibration– Leak In Line– Other Instrument Problem– Moisture In Lines



SLOPE

• Performed Only On Calibrations

• Tests To See That The Instrument Is Responding Correctly. All Instrument Responses Should Be Linear And The Calculated Slope Should Be Near The Ideal

• Ideal Slopes:

– CO = 20– Other Pollutants = 1000 (0 - 1000 ppb Instrument Range)– Other Pollutants = 2000 (0 - 500 ppb Instrument Range)


– Low Source Air Supply (Not If Concentration Spacing Test Passes)– Empty Gas Bottle (Not If Concentration Spacing Test Passes)– Span Adjustment Incorrect On Instrument– Moisture In Lines– Instrument Response Drift Due To Malfunction Or Wear



INTERCEPT


• Tests To See That The Instrument Is Responding Correctly And That The Calculated Intercept Is Near The Ideal

• Ideal Intercept = 0


– Bad Or Incorrect Instrument Zero– Moisture In Lines– Instrument Malfunction Or Wear



PRECISION


• Tests To See That The Instrument Has A Stable, Linear Response

• The Voltage Average For Each Level Is Compared To The Calculated Regression Line And Must Be Within Limits


– Instrument Out Of Whack - Order More Whack– Moisture In Lines– Calibrator Not Delivering Stated Concentration



LINEARITY

• Performed Only On Spans

• Tests To See That The Instrument Is Holding A Stable, Linear Response

• The Voltage Average For The T-Level Is Compared To The Line Drawn Between The M-Level And The G-Level And Must Be Within Limits


– Instrument Out Of Whack - Order More Whack– Moisture In Lines– Calibrator Problem



ZERO

• Performed On Both Calibrations And Spans

• Tests To See That The Instrument Calibration Is Holding Since The Last Good Calibration Or Span

• The Voltage Average For The G-Level Is Compared To The G-Level From The Last Good Calibration Or Span And Must Be Within Limits


– Low Source Air Supply– Gas Bottle Concentration Wrong– Instrument Zero Off– Moisture In Lines



SPAN


• Tests To See That The Instrument Calibration Is Holding Since The Last Good Calibration Or Span

• The Voltage Average For The M-Level Is Compared To The M-Level From The Last Good Calibration Or Span And Must Be Within Limits


– Low Source Air Supply (Not If The Spacing Test Passes)– Empty Gas Bottle (Not If The Spacing Test Passes)– Incorrect Instrument Span– Moisture In Lines




• Tests The Electronic And Flow Balance Between The NO and NOx Channels. Compares The Ratio Of The Average NO2 Span Response To The Average NO Span Response During Non-Titration Steps. Sensitive To NO2 Impurities In NO Cylinder. Impurities Give Positive Errors.

• Only Affects The Validity Of The NO2 Channel Calibration


NOx BALANCE TEST

M-Level mv G-Level mvNO2 0 17NO 1016 5

-17M-Level Balance =

51016

170100017

Numbers Are From The NOx Calibration At CAMS 12 on July 28, 1998

MNO2 - GNO2

MNO - GNO


NOx CONVERTER EFF. TEST


• Tests The Efficiency Of the NO2 NO Converter

• Affects The Validity Of The NO2 And NOx Channel Calibrations


M-Level mv M*-Level mv G-Level mvNO 1016 195 5

NOx 1012 1005 18

99M-Level Cnvtr Eff. =

181012

10051012

1951016

51016110099

Numbers Are From The NOx Calibration At CAMS 12 on July 28, 1998

MNO - GNO

MNO - M*NO

MNOX - M*NOX

MNOX - GNOX


H2S CONVERTER EFF. TEST


• Tests The Efficiency Of the H2S SO2 Converter

• Based On The T-Level And The T1-Level. Test Is Sensitive To Agreement Of The Calibrations Of The H2S Cylinder To The SO2 Cylinder. This Can Cause Both Negative And Positive Errors.


Numbers Are From The H2S Calibration At CAMS 54 on July 26, 1998

1176

1176100100

T - G

T1 - G


H2S SCRUBBER EFF. TEST


• Tests The Efficiency Of the SO2 Scrubber

• Based On The T1-Level And The T2-Level


Numbers Are From The H2S Calibration At CAMS 54 on July 26, 1998

1176

121100100

T2 - G

T1 - G


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CASE STUDIES

• Case Study #1:

– SO2 Cals/ Spans At CAMS 21 July 12, 15, 16, 1998

• Case Study #2:

– Incomplete SO2 Span At CAMS 98 July 15, 1998

• Case Study #3:

– Failed CO Span At CAMS 13 July 22, 1998

• Case Study #4:

– Incomplete O3 Calibration at CAMS 12 July 22, 1998

• Case Study #5:

– Failed O3 Calibration at CAMS 86 July 12, 1998

• Case Study #6:

– Invalid NO2 Cals At CAMS 12 July 19, 20, 26, 1998


• The Overall CAMS Summary Report Is Generally The First Place That Problems Come To Light

• This Report Does Not Have Enough Information To Determine Causes, Only That Problems Exist

WHERE DO YOU START LOOKING?


STATUS REPORT HIERARCHY

Overall CAMS Report

CAL Results Report

SPAN Results Report

High Values Report

Data Loss Report

CAL/SPAN Acceptance Report

Individual CAMS Report

The Status Reports Use A Drill-Down Technique -- The Further Down The Report Hierarchy You Go, The More Detailed The Reports Get

Level Of Report Detail

SPAN-ZERO Results Report




CASE STUDY #1CAL/SPAN HISTORY

• Another Place To Find Problems Is The CAMS Calibration History Web Page

• This Is A Quick Look At All The Cals And/Or Spans That Have Occurred

• This Web Page Has More Detailed Data Than The Overall Summary Or The Individual CAMS Summary, But Not As Much As The Calibration Or Span Report Pages


CASE STUDY #1INDIVIDUAL CAMS REPORT

• Once We Get To Here, We Can See Which Parameter Has Problems

• We Still Don’t Have Enough Detail To Determine Causes


CASE STUDY #1LOTS OF FAILURES

• At This Point, We Can Start Seeing What Went Wrong


CASE STUDY #1WHAT’S WRONG HERE?

• Poor Rise Time• Low M-Level

• Unstable• Low R-Level

• Poor Decay Time• Unstable T-Level

• Poor Decay Time• Unstable• High G-Level

• Manual Validation Provides A Strong Graphical Representation Of The Data Which Makes Data Analysis Much Easier


CASE STUDY #1VOLTAGE OUTLIER TEST

This Point Is Rejected

And A New Average Is

Calculated

• Average Voltage

• Voltage Limits

• Voltage Measurements

• This Tests The Stability Of The Instrument’s Response

• There Are Two Steps To This Test


CASE STUDY #1VOLTAGE OUTLIER TEST, PART 2

• This Is The Second Step

• New Average Voltage• Based On Three Points

This Point Doesn’t Pass Either - Outlier Test Is Failed

• The First Outlier Has Been Rejected And A New Average Is Calculated

Rejected By First Pass


CASE STUDY #1PRECISION TEST

• Average Voltages

• Warning Limit

• Calculated Slope And Intercept

• This Tests The Linearity Of The Instrument’s Response

• Failure Limit

• Actual Instrument Response

All Of These Points Fall Outside The Limits

The Instrument Does Not Have A Linear Response


CASE STUDY #1SLOPE & INTERCEPT TESTS

• Now We Check For Instrument Drift



• Ideal Intercept

• Failure Limit

• Warning Limit

• Ideal Slope

• Intercept Limits

Calculated Intercept Way Out Of Limits

Calculated Slope Way Out Of Limits

This Calibration Has Drifted Significantly From The Ideal


CASE STUDY #1SPAN REPORT

• The Failures On This Span Are Very Similar To The Failures On The Previous Calibration

• We Would Expect The Graphical Data To Look Similar As Well


CASE STUDY #1THIS SPAN LOOKS SICK

• Poor Rise Time• Low M-Level

• Poor Decay Time• Unstable T-Level

• Poor Decay Time• Unstable• High G-Level

• No Big Surprise Here -- This Looks Very Similar To The Previous Calibration


CASE STUDY #1OPERATOR LOG

• The Operator Went To The Station And Found The Temperature Low And Condensation Present In The Lines

• Based On What The Operator Found In The Station, This Was The Correct Action To Take


CASE STUDY #1INTERNAL STATION TEMP

• Internal Station Temp Is Monitored At All Sites

• Nominal Range Is:

77º F To 87º F

• As Paul Harvey Would Say: “And Now For The Rest Of The Story”….


CASE STUDY #1CALIBRATION REPORT

Concentration Spacing

Failure

Invalid Calibrations

Do Not Reject Any Data

• This Calibration Didn’t Pass Either

• Notice That The Failure Is Very Different From What We Saw Before

• This Indicates A Different Problem


CASE STUDY #1MANUAL VALIDATION

T-Level Looks Suspiciously High

• This Calibration Looks Almost Normal


CASE STUDY #1CONCENTRATION SPACING TEST

The Average Concentrations At Each Level Are Compared To The Ideal Concentrations

There Are Warning Limits For Each Level

There Are Failure Limits For Each Level

Warning Limits

Failure Limits

This Is The Problem

Average Concentration



• Another Trip To The Station Reveals The Source Of This Problem

• Just Remember, There May Be More That One Thing Wrong

• You May Have To Try Several Times Before Everything Is Fixed


INVESTIGATIVE TOOLS USED

• Web Pages

– Overall Cams Status Report

– Individual CAMS Status Report

– Calibration Report

– Span Report

– CAMS Calibration History

– Operator Log

• Manual Validation

• On-Site Troubleshooting

} Used To Initially Spot Problems

} Detailed Information About The Instrument Response During Calibrations Or Spans

Long-Term Review Of Data

History Of Findings And Actions Taken

Graphical Representation Of Data

The Only Authoritative Method


CASE STUDY #1 SUMMARY

• This CAMS Had Multiple Problems

• The First Was Moisture In The Lines Which Caused Multiple Calibration And Span Check Failures

• After The Moisture Was Removed, The Next Calibration Still Failed

• Finally Traced To Low Supply Air Pressure

• There Are Two Morals To This Story:

Keep The Station Temperature In The Correct Range To Prevent Moisture Buildup In The Lines

Go To The Station And Check The Instrument, The Calibrator, The Air Supply, The Gas Bottles, And Any Other Equipment Anytime There Is a Cal Or Span Failure


CASE STUDY #2INCOMPLETE SPAN CHECK

• Look At All The Information

• Actually, You Do Know A Lot About This Incomplete Span Check

• This Is Not An Instrument Problem Or A Calibrator Problem

• This Is A Problem Somewhere In The Comms Path OR An Operator Error


CASE STUDY #2MISSING DATA

Data Has Gone Missing

• This One Is Easy To Spot


CASE STUDY #2HUB ERROR LOG

• Now We Have To Find Where We Lost The Data

One Little Gotcha

• Look For Any Errors Around The Time Of The Missing Data

Here It Is!

(UTC Is 5 Hours Ahead Of CDT, 6 Hours Ahead of CST)

We Lost Two Five-Minute Samples

• This Entry Indicates The Data Never Made It To The Hub Computer


CASE STUDY #2ZENO DATA RETRIEVAL

• We Need To Look On The Zeno To See If We Really Collected The Data During The Span

OOPS!! The Zeno Collected

All The Data -- That Means We

Missed The Data On Retrieval



• Web Pages



– Span Report

– Hub Error Log


• Zeno Operator Interface


Not Really Useful In This Instance


See What The Zeno Actually Recorded

Shows Missing Or Scrambled Data



• This Was Clearly A COMMS Problem

• This One Was Fairly Easy To Interpret

• The Data Was Collected By The Zeno But Never Made It To The Hub Computer

• There Is Little You As An Operator Can Do About This

Happily, The Data Can Be Manually Retrieved From The Zeno And Loaded Into The System

You Didn’t Even Have To Go To The CAMS To Figure This One Out


CASE STUDY #3FAILED SPAN

Failed Span Checks Always

Reject Data Both Directions

• This Span Check Had A Different Failure Mechanism

• Notice The Low Voltage Responses

• Three New Failures Here:

– Zero

– Span

– Linearity


CASE STUDY #3DOES THIS SPAN LOOK OK?

• Low Voltages

• Poor Response

• Compare The Span Check To The Previous Calibration

• Correct Voltages

• Good Response


CASE STUDY #3ZERO & SPAN TESTS

• Ideal Zero• Based On Last Good Cal

• Ideal Span• Based On Last Good Cal

• These Tests Compare The Current Cal Or Span To The Previous Good Calibration

• Zero Limits

• Span Limits

Measured Zero Way Out Of Limits

Measured Span Way Out Of Limits

The Instrument Response Is Way Out Of Line Compared To The Last Good Cal



CASE STUDY #3LINEARITY TEST

• Now We Check The Instrument Linearity

• This Test Is Done Only During Spans


• Instrument Response Between Measured Span And Zero

• Linearity Limits T-Level Average Voltage Is Way Out Of Line



Ahhh! Here’s The Problem

Good Thing I Went To The Station To Check This Out



• Web Pages



– Span Report

– Operator Log




Detailed Information About The Instrument Response During SpanHistory Of Findings And Actions Taken





• The Span Check Response Was Radically Different From The Response Of The Last Calibration

• Instrument Could Not Reach Correct Span, T-Level Voltage Response Much Higher Than Curve -- Indicates The Calibrator Could Not Supply The Correct Concentrations

• Finally Traced To Bad Supply Pump





CASE STUDY #4INCOMPLETE CALIBRATION

• Skimpy Information Here

• Actually, You Do Know A Lot About This Incomplete Calibration

• This Is Not An Instrument Problem Or A Calibrator Problem

• This Is A Problem Somewhere In The Comms Path OR An Operator Error


CASE STUDY #4CAN YOU SEE THE PROBLEM?

• There Sure Seem To Be A Lot Of M-Levels

• Look Closely At The Different Levels


CASE STUDY #4POLLUTION DATA BY PARAMETER

• Now We Need To Find Out Why There Seem To Be So Many M-Levels On This Calibration

• Start With The Pollution Data By Parameter Web Page

• Here’s What We Can Tell From This:

– This Cal Was Not Scheduled -- Look At The Start Time

– There Were Really Too Many M-Levels -- Look At The Voltages

This Column Is Voltage


CASE STUDY #4ZENO DATA RETRIEVAL

Just To Be Sure, Let’s Check What’s On The Zeno

OOPS!! This Really Happened



• Web Pages



– Span Report

– Pollution Data By Parameter


• Zeno Operator Interface


Not Much Data Here

Tabular Listing Of Five-Minute Data


See What The Zeno Actually Recorded



• I Really Didn’t Tell You Everything -- This CAMS Was Having A Rash Of Calibration Problems

• An Operator Was In The Station, Made Some Sort Of Adjustment And Then Spanned The Instrument Up To An M-Level

• It Looked Good So The Operator Fired Off A New Calibration

There Has To Be At Least 5 Minutes Of Ambient Data Collected Between Cals, Spans, Or Even Manual Levels In Order For The Automatic Software To Detect A Valid Cal Or Span

This Is Also A Really Good Reason To Not Change The Standard Calibration Schedule


CASE STUDY #5PRECISION TEST FAILURE

Failed Precision On Cals

Rejects Data Both Ways

• Everything About This Cal Looks Good But The Precision Tests


CASE STUDY #5I DON’T SEE ANYTHING WRONG

T-Level Looks Slightly Low

• The Data Before And After This Calibration Has Been Recovered By A Data Validator -- It Used To Be Flagged LIM


CASE STUDY #5PRECISION TEST


• Warning Limit


• This Tests The Linearity Of The Instrument’s Response

• Failure Limit

The T-Level Average Voltage Falls Outside The Limits - The Instrument Does Not Have A Linear Response


CASE STUDY #5CAMS 86 CALIBRATION HISTORY

• Let’s Take A Peek At The CAMS Calibration History

• Notice That The Voltage Averages For All The Levels Of The Failed Cals Are Higher Than In The Previous Good Cals

• Except For The T-Level, Which Is Noticeably Lower

• Gee, I Wonder What The Ozone Generator Is Doing -- Guess I’ll Have To Go To The Station And Find Out



Well Look Here…

Good Thing I Went To The Station Check This Out



• Web Pages




– Span Report


– Operator Log











• The Precision Test Picked Up A Calibrator Problem

• Indications Are That The Ozone Generator Could Not Produce Enough Ozone

• This Is Especially Evident At The T-Level Where The Flow Is Very Low





CASE STUDY #6July 19, 1998 NO2 CAL

Invalid -- Doesn’t Affect Data

• NO2 Failures Of This Kind Are Particularly Nasty To Troubleshoot

• This Is Because We Don’t Inject NO2 Directly During Calibrations -- It Is Produced By Gas Phase Titration


CASE STUDY #6BUT WAIT, THESE ARE DIFFERENT

• It’s Frustrating, But The NO2 Concentrations Reported By The Cal And Span Reports Are Different From What You See In Manual Validation Or Other Web Pages

This Is From The Cal Report

This Is What You See In The Other Web Pages And Manual Validation


REMEMBER HOW NO2 CONCENTRATION IS CALCULATED

NO Voltages And Concentrations NO2 Concentrations

5328

94328160116


CASE STUDY #6JULY 19 CONCENTRATIONS

5328

94328160116

T-Level NO Average Voltage

T*-Level NO Voltage

G-Level NO Average Voltage

T-Level NO Average VoltageT-Level NO Average Concentration

T*-Level NO2 Concentration

Fundamental Problem: T*-Level NO2 Concentration Is Too High


CASE STUDY #6EQUATION ANALYSIS

5328

94328160116

Fundamental Problem: T*-Level NO2 Concentration Is Too High

What Can Cause This Problem?

• T-Level NO Concentration Too High

– Not Likely Since NO Passed Calibration With Flying Colors; Ideal T-Level Concentration Expected To Be 160

• T-Level NO Average Voltage Too High

– Not Likely Since NO Passed Its Calibration With Flying Colors; Ideal Voltage Response Expected to Be 320

• T*-Level NO Voltage Response Too Low

– This Looks Like The Problem; Should Be Near 140

• G-Level NO Average Voltage Too Low

– Not Likely Since; Ideal Voltage Response Expected To Be 0

This Should Be About 90

This Looks Like The GuiltyParty. This Is Measured During The Titration Step.


CASE STUDY #6RUNNING DOWN THE PROBLEM

• The Calibrator May Be Producing Too Much Ozone

• The NO Cylinder Concentrations May Not Be Right

• T*-Level NO Voltage Response Too Low - Indicates The Instrument Is Not Seeing The Expected Amount Of NO

• The NO Cylinder Concentrations And The Ozone Generator Settings May Be Incompatible

• During NOx Calibrations, Everything Is Set To Provide A Buffer Of 70 ppb Of NO During Titration Levels - Just In Case There Is Too Much Ozone Produced -- For The T*-Level, 90 ppb Of Ozone Is Introduced Which Should Leave 70 ppb of NO

• The NOx Instrument May Be Reading Low

• There May Be An Air Supply Problem

• Bottom Line: You Must Go To The Station And Troubleshoot


CASE STUDY #6INVALID NO2 CALIBRATIONS

• So What If The T*-Level NO Voltage Response Is Too Low?

• Notice That The Average Voltages For All NO2 Levels Is Higher For The Invalid Cals Than What It Was For The Last Good Cal

• Also Notice That The Average Voltages For All NO Levels Is Lower For The Invalid NO2 Cals Than What It Was Before



Sure Enough, The NO Instrument Span And Zero Was Adjusted And This Appears To Have Fixed The Problem

Good Thing I Went To The Station Check This Out



• Web Pages




– Span Report


– Operator Log











• The NO2 Concentration Spacing Test Picked Up A Problem

• Indications Are That We Weren’t Measuring Enough NO

• NOx Calibrations Are Complicated - Especially The NO2 Part; There Are Lots Of Interdependent Things Going On; A Call Back To A Higher Authority Probably Wouldn’t Hurt



WHAT DO I DO ...

• I Had An INCOMPLETE Cal Or Span

Check The Web Pages And Manual Validation -- If There Was A Power Outage There Is Nothing That Can Be Done; Otherwise Call A Sys Admin To Reload The Data

• I Had An INVALID Or FAILED Cal Or Span

Don’t Start Another Cal Or Span Until You Figure Out What The Problem Is

Examine The Web Pages For Clues

Go To The Station And Troubleshoot The Equipment

• I Had Warnings On My Cal Or Span

Examine The Web Pages For Clues

Go To The Station And Troubleshoot The Equipment


FINI

This Concludes Advanced Cal/Span Interpretation

Documents

LEADS/EMS ADVANCED CAL/SPAN INTERPRETATION