Process Alarm Management

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Gregory Chng Boon Hwee

Yokogawa Engineering Asia

Process Operation Solution

Process Solution Centre, Yokogawa Engineering AsiaCopyright © by Yokogawa Engineer Asia5/13/2005 3:09:41 PM

Process Alarm Management

Friday, May 13, 2005



Process Operation Centre, Yokogawa Engineering Asia

Copyright © by Yokogawa Engineering Asia 5/13/2005 3:09:41 PM Page 2

1. Advanced Operation Assistance (AOA) Solution





Advanced Operation Assistance (AOA) Solution

Upper solution of process operation done by operatorsTo assist daily work of production people to realize safer and more

cost-effective operation. For example, – In desk work • Support to prepare an operation report

• Support to turn up operation related problems• Support to standardize operation know-how

– In normal operation• Suppress unnecessary DCS alarms to notify only important DCS alarms

• Notify an early sign of abnormality faster than it is detected by DCS alarms• Prevent miss-operation

– In transition operation (e.g. startup/load change/reactor switchover)• Give an adequate instruction to the operator in a sequential order• Prevent miss-step/miss-procedure

Process

CONTROL domain OPERATION domain

MES, ERP

Process Control (DCS)

Advanced Process Control Advanced Operation Assistance

Process Operation (Operators)





Difference between APC and AOA

APC (Advanced Process Control)

– Position: Additional function of DCS – Purpose: Improvement of controllability – Configuration: Runs on additional PC – Main user: Engineering people – Approach: Based on mathematical process model

– Benefit: More cost-effective control

AOA (Advanced Operation Assistance) – Position: Additional function of DCS – Purpose: Improvement of operation work

– Configuration: Runs on operator’s console or additional PC – Main user: Production people (operator/process engineer) – Approach: Based on knowledge and experiences of skillful

operator/process engineer – Benefit: Safer and more cost-effective operation





System architecture

Run on HIS or Additional PC

Supports Windows2000/XPproServer/client configurationComponent software – Exaopc

(OPC interface package)

– Exaplog(Event reporting/analysis package)

– Exapilot(Operation efficiency improvement package)

• Exapilot Professional or Standard• Advanced alarm function• MS Excel link icon

Support all DCS via OPCinterface

HISENG

FCS

V net

AOA Client

Ethernet

PC

PC

FCS

HF bus

ABCBus

converter

Setting

AOA Server

Gathering

Setting

Gathering

CENTUM-XL, V

Micro XL

Event message

Gathering

(max. 4)

AOA Client

CENTUM CS 1000

CENTUM CS 3000

Exaopc is required

System architecture

(In case of additional PC)





2. Exaplog

Event reporting and analysis package

2.1 Operation event viewer/analyzer

2.2 Operation event reporter





Assist desk work of production Dept. – Reporting of operational event

– Monitoring of operational event

– Analysis of operational event

Utilize a DCS alarm and event message whichis less frequently used

Exaplog

Message Printer

Huge

Running Cost

Huge

Storage Space

Specialistic

Manual Work

Exaplog (Software Printer)

Minimum

Running Cost

Minimum

Storage Space

Semi-automatic

Work





2.1 Operation event viewer/analyzer

5 viewers

– Event balance trend (EBT) – Monthly/Weekly EBT

– Category sort

– Point ID (Tag) sort

– Message summary

(same as DCS printer)

5 filters – Scope in

– Exclude – Character

– Process unit

– User defined

Event balance trend (EBT) Category sort

Point ID sortMessage summary

Character/Process unit

User defined

Monthly/Weekly EBT





Event balance trend (EBT)

Process Requests

Operator’s Actions

X-axis : Time (24hours)

Y-axis : Number of events

Display the balance between – Process requests (+)

• System alarm• Process alarm

• Annunciator message• Operation guidance, etc.

– Operators actions (-)• Tag data entry

• Tag mode change, etc.

No. Pattern Type EBT Pattern Suspected Problem Countermeasure

Long term analysis about seasonal change

Long term analysis about erosion/corrosion

Unnecessary alarms/messages Retuning of alarm set values

Integration of redundant alarms/messages

Masking of low priolity alarms/messages

Low automation rate Automation using DCS

Manual operation according to know-how Automation using Exapilot

Complex operation sequence Simplify operation sequence

Lack of support function Navigation using Exapilot

Insufficient Operator capability Operator training

Human error Error detection using Exapilot

Unstable process Introduction of advanced process control

Excessive Operation

Operator Work Overflow

Inadequate Operation

I

II

III

IV

V

No urgent problem

Redundant alarms/messages

Balanced

Excessive Nortification





Category sort, Point ID sort

Category sort

– Type – Sub type

– Detail

– Batch ID

– Station

Point ID (Tag) sort – Tag

– Tag + Detail





2.2 Operation event reporting

Various reports can be exported to CSV file

– Tag list which notifies many alarms• Per detail (e.g. HH/HI/LO/LL/VEL/DEV/IOP)

• Per priority (e.g. High/Medium/Low)

• Per process unit (e.g. station#, process unit filter)

– Tag list which alarm set point have been changed – AOF (alarm off) tag list

– Manual control tag list, and more

Additional editing can be done using MS-Excel

User defined report can be registered





(4)

(1)Select “Sub Type” tub

(2)Select “Tag Alarm”

(3)Press “Scope in filter” button

(4)Select “Tool\Export Result”

to save a result of analysis as CSV file

(5)Edit a report file using MS-Excel function

(1)

(2)

(3)

(5)

e.g. Tag list which notifies many alarms





(1)Select “Detail” tub

(2)Select “MAN”

(3)Press “Scope in filter” button

(4)Select “Tool\Export Result”

to save a result of analysis as CSV file

(5)Edit a report file using MS-Excel function

(1)

(2)

(3)

(4)

(5)

e.g. Tag list which controlled manually







Pharmaceutical plant, USA

The background

– Large batch chemical plant – Legacy system was replaced to CS3000 – Over 10,000 I/O

The problem – 50,000 alarms per day

– Audible alarms were disabled• Operators where missing critical alarms• Alarms were disappearing from display in 10 minutes• Lost production• Increased safety hazards• Increased production cost





The approach – Use Six Sigma methodology

– Set overall goal of 10 alarms/day – Use Exaplog to measure and analyze alarms

The result – Cut the alarming rate by a 98%

• Field improvement – Improvement of field instrumentations (re-ranging)

• Alarm optimization and management – Elimination of nuisance Opeguide messages – Retuning of alarm threshold

– Two of the four operator stations back on-line – Operator mistakes have decreased – Productivity has increased by notification of adequate

alarms – Operating issues around several pieces of equipments

have been resolved by systematic alarm analysis





PTA, Southeast Asia

Benefits

– Eliminate unnecessary DCS alarm events and operation for40%

– Improve inefficient operation sequences

– Operator can concentrate on only necessary alarm events

– Lower miss-operation

Process Alarm

Daily

Average

(Before)

TI-xxxx, HH alarm 73 30

TI-xxxx, Hi alarm 145 Change to proper HI alarm setting 50

LC-xxxx, Auto mode 27 PID tuning 0

LC-xxxx, Man mode 26 PID tuning 0

Change to proper HH alarm setting

Countermeasure

Daily

Average

(After)





3. Exapilot

Operation efficiency improvement package





Exapilot

Additional DCS function for – Knowledge-based process control

– Knowledge-based process monitoring

Application can be programmed as flow chart or logic chart – Specialist programming skill is not needed

– High usability

– High understandability – High maintainability

Existing application in DCS is no need to modify

Various usages – Automation of transient operation

– Alarm management

– Operator training





Flow chart programming tool (Standard)

Visible icons

for flow chart program

Application example

Application example





Logic chart programming tool (Option)

Application example

Grammar of logic chart

Visible icons

for logic chart program





Ready-made templates

For flow chart

For logic chart





3.1 Alarm Management

(1) Masking of unnecessary DCS alarm

(2) Dynamic alarm setting(3) Addition of pre-alert

(4) Replacement to advanced alarm

(5) Prevention of miss-operation





What is required to the alarm system ?

For safer and more cost-effective operation of industrial systems – To help the operator to correct potentially dangerous situations

before the ESD is forced to intervene – To recognize and act to avoid hazardous situations

– To identify deviations from desired operating conditions that couldlead to financial loss

– To better understand complex process conditions

An effective alarm system

TargetNormalUpsetShut

Down

Key Alarm Information

X X

XX X X X X X

XX XXXXXXX X

X X X X X X X

X X

X X X X X X

X XPlant State

ESD

needed

Operator

intervention

needed

Minor operating

adjustment

needed

X = Alarm

EEMUA No.191

i f





20152 alarms/day

Refinery Phenol plant

5274 alarms/day

Unnecessary alarms notified despite safe or efficient operationNecessary alarms not notified despite unsafe or inefficient operation(it’s not general because alarm must be set narrowly for safety reasons)

However, in fact…

Demand to additional alarm management function

5471 alarms/day

PTA plant

An ineffective alarm system

TargetNormalUpsetShut

Down

Key Alarm Information

X X

XX X X

X

X

X

X

X XXX

X

X

X

X

X

X X

X X

X X

X

X

X X

X

X

X X

X

X X

Plant StateESD

needed

Operator

intervention

needed

Minor operating

adjustment

needed

X = Alarm

EEMUA No.191

(1) M ki f DCS l





(1) Masking of unnecessary DCS alarm

Masking of unnecessary HI/LO alarm – Because alarm threshold is unmatched

Masking of longstanding false HI/LO alarm – Because alarm hysteresis parameter is unmatched

Re-activation of longstanding true HI/LO alarm – Because still function of CENTUM is not used

Masking of oscillation HI/LO alarm – Because PID parameters are unmatched

Masking of repeating annunciator message – Because appropriate DCS sequence (delay timer) is not prepared

Masking of unnecessary IOP/IOP- alarm – Because tag range is unmatched (range over)

Fault diagnosis for necessary IOP/IOP- alarm – Because field transmitter is failed – Because wire is come down

1. Detect and suppress unnecessary DCS alarms automatically

2. Display the reason of occurrence as countermeasure

3. Report a suppressed alarms list

A) R ti HI/LO l ( ki l i )





A) Repeating HI/LO alarm (masking logic)

Monitoring

period

Note) Mean: PV moving average, Dev: PV standard deviation, SH: Scale HI, SL: Scale LO, A: parameter (default=2)

(1) IF New_PH= Mean - 3 x Dev >= Original_PL + 0.1 x (SH - SL) & |New_PH - Mean| >= |Original_PH - Mean|

THEN New_PH = Mean - 3 x Dev

(2) IF New_PH = Mean - 3 x Dev <= Original_PL + 0.1 x (SH - SL) & |New_PH - Mean| >= |Original_PH - Mean|

THEN New_PH = Mean - A x Dev

SL

SH

Original_PH

Original_PL

Start

monitoring

1 2 3

New_PH

Number of

occurrence

HI HI HI

Time

PV

Start

masking

PurposeThis logic can mask an unnecessary HI/LO alarm

which is slowly oscillating near PH/PL.

Logic

This logic consists of “monitoring” logic, “masking”

logic and “recovery” logic. Monitoring logic is started

when first HI/LO alarm is occurred, and then

monitors the number of occurrence while ordered

monitoring period. In case the number reaches anordered times, masking logic is run.

Masking logic

PH/PL is automatically changed so that new PH/PL

is not announced. The reason of suppression is

displayed as a countermeasure.

Reason of occurrence: Alarm threshold is unmatched

A) R ti HI/LO l ( l i )





A) Repeating HI/LO alarm (recovery logic)

Recovery logic

Condition 1:

IF Mean + 3 x Dev < Original_PH or Original_PH < Mean – 3 x Dev

THEN Return to Original_PH

Condition 2:

IF New_PH>= Mean


(In case the maximal value of oscillation is greater than Original_PH, HI alarm will be notified again)

Condition 3:

IF |Original_PH– Mean| >= |New_PH – HYS x (SH – SL) – Mean| (HYS=0.02)


(In case the maximal value of oscillation is greater than Original_PH, HI alarm will be notified again)

SL

SH

Original_PH

Original_PL

New_PH

Time

PV

Mean Mean Mean

|Original_PH - Mean|

|New_PH – Hys x (SH – SL) – Mean|

Hys x (SH-SL)

3 x Dev

3 x Dev

Condition 1 Condition 2 Condition 3

Mean

B) L t di f l l





B) Long standing false alarm

Monitoring period

S

L

SH

Original_PH

Start

monitoring

New_PH

HYS x (SH - SL)

HI NR

Time

PV

Start

masking

Purpose

This logic can mask unnecessary HI/LO alarmwhich is lower/higher than PH/PL but still in

the band of hysteresis.

Masking logic

In case PV is in the band of hysteresis formonitoring period, PH/PL will be changed tohigher/lower vale momently.

3 x Dev

Mean

HYS x (SH - SL)

3 x Dev

2sec

Reason of occurrence: Hysteresis parameter is unmatched

Note) Mean: PV moving average, Dev: PV standard deviation, SH: Scale HI, SL: Scale LO, HYS: parameter (default=0.02)

IF PH/PL is in activation AND

Mean + 3 x Dev < Original_PH & Mean + 3 x Dev > Original_PH– HYS x (PH – PL)

THEN New_PH = Original_PH + HYS x (PH – PL) for 2 seconds


THEN New_PH = Mean - 3 x Dev

Stop

masking

C) L t di t l





C) Long standing true alarm

Monitoring

period

IF HI/LO is activated for ordered period & Mean + 3 x Dev >= Original_PH

THEN New_PH/New_PL= SH/SL, 2 seconds later, Return to Original PH/PL

S

L

SH

Original_PH

Start

monitoring

New_PH

HI NR

Time

PV

Re-

notification

Purpose

This logic re-notifies longstanding true

HI/LO alarm.

Re-notification logic

In case true HI/LO alarm is activated formonitoring period, PH/PL is changedmomently to SH/SL, so that PH/PL isannounced again.

HINR HI

Monitoring

period2Sec

Mean3 x Dev

HH

Reason of occurrence: Still function of CS3000 is not used

D) O ill ti l





D) Oscillation alarm

Monitoring

period

SL

SH

PL

Start

monitoring

PH

Time

PV

Start

masking

Purpose

This logic masks unnecessary HI/LOalarms by setting AOF in case PV is

oscillated due to the mismatch of PIDparameters.

Masking Logic

In case HI/LO alarms are notified one afterthe other for ordered times, Exapilot sets

AOF. (Select HH or HI, LO or LL)

Recovery Logic

In case HI/LO alarms are not notified forordered period, Exapilot sets AON.

(In case PID is not retuned, HI/LO alarms

are continuously masked)

AOF

Monitoring

period

1 2

AON AON

Occurrence

number

Stop

masking

1 2

LL

HH

HI HI

LO LO

PID is retuned

Reason of occurrence: PID parameter is unmatched

E) Repeating Annunciator message





E) Repeating Annunciator message

Monitoring

period

Start

monitoring

Purpose

This logic masks an unnecessaryannunciator which announced repeatedly.

Masking logic

In case annunciator is announced orderedtimes in monitoring period, AOF is set to

target annunciator (%AN). Then target tag isregistered as habitual.

ON

%ANNOFF

AON

Monitoring

period

TimeMonitoring

period

1 2 3

Occurrence

number

Start

masking

Recovery logic

In case annunciator is not announced formonitoring period, AON is set to target

annunciator (%AN).

Masking logic (After learning)In case registered tag announced

annunciator again, AOF is set without waiting.

Reason of occurrence: DCS sequence is not prepared

Stop

masking

AOF

F) Fault diagnosis and suppression of IOP alarm





F) Fault diagnosis and suppression of IOP alarm

Monitoring period

S

L

SH

Judgment

HI IOPRAW

Purpose

This logic detects true IOP/IOP- alarms

which announced due to range over.

Detection Logic

In case IOP/IOP- is happened after HI/HH

or LO/LL alarm is notified, and is recoveredafter ordered period, this logic shows thereason of IOP/IOP- alarm (range over).

Also target tag is registered as habitual.

Exclude logic

In case registered tag announces IOP/IOP-

alarm again, target tag is excluded from

watch list.

HHNR HH

HH

PH

HI

IOP

Start

monitoringMonitoring period

for IOP detection

Reason of occurrence: Range over (engineering problem)





Start

monitoring

(0%)SL

(100%)SH

IOP IOPRAW

Purpose

This logic masks unimportant IOP/IOP-

alarm which announced due to range over.

Masking logic

In case registered tag is in AON, and RAW

data of registered tag is greater than SH orsmaller than SL for monitoring period, AOFis set.

Recovery logic

RAW is returned between SL and SH, AONis set.

Normal

Range

IOP-

IOP

Normal

Range

Normal

Range

Time

AON

Stop

monitoring

Start

masking

Stop

masking

AOF





SL

IOP

Judgment5Sec

IOPRAWPurpose

This logic detects true IOP/IOP- alarm

which notified due to the failure of fieldtransmitter.

Detection logic

In case IOP/IOP- is happened even though

HI/HH or LO/LL alarm is not notified, orIOP/IOP- is happened immediately (within

5 seconds) after HI/HH or LO/LL alarm isnotified, this logic shows the reason ofIOP/IOP- alarm (failure of field transmitter).

Also target tag is registered as habitual.

Masking logic

In case registered tag announces IOP/IOP-alarm again, AOF is set continuously.

NRNR NR

HH

PH

IOP

JudgmentStart

monitoring

Startmonitoring

SH

Monitoringperiod

Monitoring period

HI

AON

Reason of occurrence: Failure of field transmitter

AOF

HH





SL

SH

Judgment

IOPRAW

PurposeThis logic announces the reason of trueIOP/IOP- (breaking of wire) alarms.

Detection Logic

In case IOP/IOP- is notified even thoughHI/HH or LO/LL alarms are not notified,

and IOP/IOP- is not recovered for ordered

period, this logic shows the reason of alarmnotification.

NR

LL

PL

IOP-

Monitoring periodStart

monitoring

Reason of occurrence: Breaking of wire

(2) Dynamic alarm setting





(2) Dynamic alarm setting

Alarm threshold (PH/PL) should be changed dynamically according to thedrastic changes of set point (e.g. load change, grade change)

Exapilot Excel Link icon (option) reads optimum alarm threshold (PH/PL)to FCS automatically when SV is drastically changed

Exapilot Correlation Diagnosis icon (Advanced Alarm option) can monitorthe correlation between elapsed time and process variable (PV) online

Start up Grade A Grade B

GradeChangeShut down

PH=100

PL=80PH=SV + 5

PL=SV - 10

PH=SV + 10

PL=SV - 12

PH=200

PL=180 PH=SV + 4

PL

=SV – 6

PH=SV + 4

PL=SV - 2 TIME

PV





Case Branch icon

In case of

Grade A

Repetition

Out put to

DCS icon

A B C D E

GRADE AGrade A Grade B

Grade CGrade D

For the transient condition





For the transient condition

Correlation diagnosis icon

(3) Addition of pre-alert





(3) Addition of pre-alert

S

L

SH

PL

Start

monitoring

PH

Time

PV

Start

monitoring

Purpose

This logic announces pre-process alert incase;

-PH/PL is announced

-PV is increasing/decreasing-PV will reach HH/LL within ordered period

(e.g. within 5 minutes)

HH LO

LL

HH

NR HI NR LL

Notify

HH pre-alertNotify

LL pre- alert

Period of

notification

Period of

notification

Pre-alert function predicts an indication of HH/LLalarm before HH/LL is announced, and displays alert

message to operators to prevent ESD.







Various kinds of diagnosis templates (Standard/Option) – Fault diagnosis

• Field transmitter (e.g. Failure, Breaking of wire)

• Control valve (e.g. Sticking, Leakage, Clogging of strainer)• Pump (e.g. Trip)• Pipe (e.g. Clogging, Leakage)• Storage tank (e.g. Leakage)

– Overload monitor• Pump• Compressor• Turbine• Centrifuge• Blower• Agitator

– Operation efficiency monitor• Heat exchanger (e.g. Energy effectiveness)• Distillation tower (e.g. tray performance, Temp. distribution)• Reactor

– Quality monitorDetect an early sign of abnormality faster than it’s detected by DCSalarmsNotify the reason of alarm and adequate countermeasure to operatorsSend e-mail to relevant peopleExecute countermeasure automatically if necessary



Application examples





Application examples

This logic detects the abnormality of cylinder valve in

reciprocating compressor by comparing the difference

between estimated outlet temperature and measured outlet

temperature.

In case cylinder valve is broken or quantity of cooling water

is insufficient, the outlet temperature will be risen due to

back flow inside of cylinder.

Example1: Reciprocating compressor diagnosis

Example2: Correlation diagnosis

Correlation diagnosis icon

T TTI101.PV TI102.PV





Exapilot can define pre-alert which can detect early

sign of process abnormality before it is detected byprocess HI/LO alarms.

Example3: Reactor temperature distribution diagnosis

TI102.PH

TI102.PV

1 hour

5 degrees





P

P

PI101.PV

PI103.PV

P

PI102.PV

Low pressure steam

(-0.1 MPa <= PI101.PV-P102.PV <= 0.1 MPa)

(-0.1 MPa <= PI101.PV-P103.PV <= 0.1 MPa)

Guidance message

Example4: Pressure indicator diagnosis This logic detects the abnormality of pressureindicator by checking the difference of threepressures.

Furnace

FI103.PV

FI101.PV

FI102.PV

TI100.PV

TI200.PVLowMaterial A

LowMaterial B

FuelGas

XI103.PV

Example5: Furnace incomplete combustion diagnosis

This logic detects early sign ofincomplete combustion infurnace unit before DCS HI

alarm detects it, by monitoring

the difference between “Fuelgas calorie” calculated using

fuel gas flow & gravity and“Furnace duty” calculatedusing flow & temperature of

furnace unit.

(5) Prevention of miss-operation





(5) Prevention of miss operation

Incorrect action must be detected ASAP to preventserious trouble

Exapilot Advanced Alarm can detect various kinds ofmiss-operation by monitoring operator’s behavior

Example: Miss of tag mode change

IFFIC100.MODE is changed to “MAN”

3 minutes lapsed

FIC100.MODE is still in “MAN”

THENExapilot changes tag mode to “AUT”





3.2 Operator training system

Training system





Training system

Use Exapilot and CS 3000 test function (WDA)

No need to modify existing DCS application

Low cost system

Simple process model can be made in Exapilot

– Dead time – Time lag

– Material balance, etc.

General training using HIS windows

Training for transition operation using Exapilotwindow





Simulate the material balance

between valve position

and tank level

Simulate the material balance

between valve position

and tank level

FIC

FIC

Level

TIC

Field

controller

Hotwater

CENTUM CS 3000 Test function

Simulate a field

temp. controller

Simulate a field

temp. controller

Temp

Exapilot

Read PV/MV/SV

Write RAW

Read PV/MV/SV

Write RAW

Dead time

Time lag

Dead time

Time lag

Exapilot application for process simulation

Exapilot application for automation of transition operation

Read PV/MV/SV/PH/PL/ALRM

Write SV/MV/PH/PL

Read PV/MV/SV/PH/PL/ALRM

Write SV/MV/PH/PL



Thank you for your attention.Thank you for your attention.

Documents

Process Alarm Management