modern plant control centers and operator control concepts_k1

7/27/2019 Modern Plant Control Centers and Operator Control Concepts_K1

1/9

A white paper issued by: Siemens. Siemens AG 2012. All rights reserved.

February 10, 2012

Summary

This a rticle prese nts a user-centric concept for structuring indus-

tria l process con trol. The b a ckgroun d to th is concept is the con-

sta ntly increa sing ly complexity o f t he processes to b e m onitored

and t he w orking environ ment in control room s from the perspec-

tive of the operato rs. The use of m ode rn pla nt control cente rs

and operat or control concepts can support a nd o ffload operators

in the execution o f their ta sks by mea ns of a pow erful huma n

machine interface.

Modern p lant control centers

and operator control concepts

HMI+ supports operative p rocess

control of industrial production

processes by m eans of user-centricprocess visualization

Dipl.-Ing . S. Kempf, Siemen s AG, Karlsruhe

Dipl.-Ing. L. Glathe, Siemens AG, Frankfurt


2/9


White Paper | Modern plant control centers and operator control concepts | February 10, 2012 2

Content

HMI+ supports operative process control of industrialproduction processes by means of user-centric process

visualization..............................................................................31. Introduction........................................................................ 32. Concept of user-centric process visualization ........................... 33. Display and operator control concept using the example of

a batch column..................................................................... 64. Conclusion.......................................................................... 8

Bibliography ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9


3/9



1. Introduction

The primary t ask of the o perato r is to ca rry out

operat ive process cont rol on t he b asis of process

and plant informat ion from the production process

and its log istics and auxiliary processes [1].

Operative process control aims to maintain the safe

operation of the production plant in accordancewith requirements, to maximize the availability of

the production system despite isolated faults, an d

to g uarantee product q uality despite fluctuat ions in

raw material quality, faults in the plant, and va ria-

tions in throughput [5].

Finally, the process sequen ce must b e optimized

w ith rega rd to costs, qua lity and safety.

The o perato r's prima ry ta sks a re extende d in pa r-

ticular by high cost pressure, for example throug h

mat erial planning t asks, b roa der qua lity assurance

and ef ficient operation of the plant.

These extend ed t asks are traditiona lly cont ained in

the area o f the plant control level.

The req uired informat ion is presented to t he ope ra-

tor in centralized cont rol structures, ma inly via the

display and operator control components of t he

process control system in the co ntrol roo m. Fur-

thermore, additional information from a heterog e-

neo us system w orld, e .g. PIMS, ERP, LIMS etc., must

be supplied to the operator and presented in rela-

tion to the task. This heterogeneo us autom ation

landscape increases the complexity of the working

environment of control room operators.

In a ddition, the rising level of a utoma tion of today's

industrial produ ction processes results in a reduc-

tion in the numb er of control room personnel and,

in parallel, in a sh arp increa se in the volume of

process information to be mo nitored by ea ch opera-

tor, caused, fo r example, by comb ining control

rooms.

This increa sing co mplexity in product ion processe s,

as w ell as the w orking environment in control

rooms, m akes it diff icult for opera tors to

form a holistic ment al picture of the plant and

processes to be mo nitored. But precisely this men-

tal picture is hugely important for monitoring the

sta tus of the plant/process.

The use of user-oriented an d t ask-oriented concepts

of fers a solution to this problem. These a re aimed

at creat ing integrated w ork systems, i.e. combined

optimization o f th e a pplication o f t echnology, or-

ga nization, and q ualification of t he user. Instead o fada pting people to technology, technology must be

ada pted to peo ple [2].

Starting from the planning phase of process plants,

the se a spects of user-centric process visualizat ion

must b e sufficiently ta ken into account in the de-

sign and conceptua l definition of plant control

centers and operator control concepts.

This user-cen tric hum an m ach ine inte rfa ce (HMI),

referred to be low as HMI+ , ha s a crucial share in

this. In the remainder of this article, special atten-

tion is given to the design o f operator consoles and

their elements an d st ructures.

2. Concept of user-centricprocess visualization

The display an d opera tor cont rol concept for plant

operators has change d significant ly in recent years.

Where previously mosa ic pa nels w ere used for op-

erator control, today the operator sits a t a PC w ork-

stat ion w ith, for example, 4 screens. Until now, the

benefits of t he mosa ic panel and recorder, such as

clear representation of process states, were rarely

ado pted for PC w orkstat ions. Rather, the focus w ason eye-catching g raphics w hich w ere, how ever, o f

no great benefit in performing t he actua l operato r

task.

Visualization systems and processes used today

ach ieve positive results only in some a reas; fo r

example, individua l plant sect ions or sub-processes

can be clea rly represented using g raphics displays.

HMI+ supports operative process control of industrialproduction processes by means of user-centric processvisualization


4/9



The syste ms a re charact erized by:

A mishmash of different devices a nd softw areproducts w ith non-homog enous ope rator inter-

faces

Multiple input a nd o utput devices per PC at t heoperator wo rkstat ion

Standa rd configuration of operato r workstat ions(e.g. a lwa ys 4 screens per client)

Cost-driven workstation designHow ever, th e processes used to represent process

values display w eak points w ith regard to t he fol-

lowing

Display o f the o verall sta tus of t he process - thebig picture

Operators receive information predominantlythrough t he use o f a lphanume ric displays instead

of a nalog representa tions with pat tern recogni-

tion

Attraction of t he operator's attention by mea nsof sha pe-coding and co lor-coding

Task-relat ed a nd ac tivity-relate d visualizat ion Display o f informat ion

Fig. 1: HMI+ , user-centric concept for designing industrial

process control in acco rdance w ith [3]

The concept a nd design pha ses are also accompa -

nied by conceptua l wea knesses:

Process pictures are crea ted o n the b asis of iso-lated piping a nd instrumenta tion diagrams w itha different display purpose

Particularly in new plants, it is not po ssible toinvolve the operating personnel in the design

process at a n early sta ge

Lack of a process visualizat ion sta nda rd encom-passing all devices

Lack of process know -how in the d esign processHMI+ , a user-cent ric concept fo r designing indus-

trial process control, is described below (see Fig 1).


5/9



This concept combines t horoug hly fam iliar ele-

ments a nd structures of operator control units, such

as o perator interfaces a nd the ir procedures, with

the design of operato r consoles and control rooms,

and organizational measures to form a holistic solu-

tion a pproach.

The st art ing point fo r all considerat ions is the de-

tailed ana lysis of operato r tasks with regard to

process control and additional tasks in the control

room area (see th e exa mples in Tab le 1). This an aly-

sis must be ca rried out specifically for each plant o n

a project-related basis and with the involvement of

the team of o perators.

No. Tas k Job fun ction Activity Req uiremen ts fo r process visu-

alization

1 Process control Monitoring an automat ed

plant

Monitoring essential

operating parameters

(process-relate d KPIs)

Overview d isplays with essen tial

operating parameters of the

plant to b e monitored

Display of the permissible to ler-

ances

Display of limit violat ions

Display of a larms and their

priorities

Ana log displays for "patt ern

support"

Trend displays f or as sessing

situations and deciding on

operating strategy


plant

Detec ting /perceiving

faults

Attracting a ttention by means o f

color schem e with distinct alarm

colors

Avoidan ce of cog nitive

overload


plant

Find ing /ident ifying the

cause of the f au lt

Jump function from alarm pa ge

to th e measuring point in the

process picture

4 Materials plan-

ning

Planning ma terials Entering recipe param e-

ters

Uniform and device-neutral

presentation of th e operator

screen forms

Use of the same input and ou t-

put devices as for process con-

trol

5 Documentation

for process

control

Keeping a shift logbo ok Ente ring the relevant

process value in the shift

logbook

Presentation of all relevant

process values (in a log)

6 Extended qua lity

assurance

Monitoring of quality-

related process parameters

Monitoring of quality

KPIs

Visualization of quality KPIs in

overview d isplays of th e process

control system

Device-independent, homo ge-

nous presentat ion of the qu ality

KPIs

Tab le 1: Requirements f or process visualization resulting from o perator t asks


6/9



In a ddition to project-specific issues, the follow ing

generally valid issues for improving process visuali-

zation have been derived from the prioritization of

the requireme nts for process visualizat ion (cf. Table

1):

Proced ure for represent ing process values:

Additional use of abstract operator procedures inw hich the process topolog y plays a subordinate

role. For example: process-relat ed o verviews

w ith essential operating parameters of the plant

to be mo nitored in an a rrang ement of hybrid

displays w ith tolerance a nd limit value visualiza-

tion th at suppo rts patt ern recog nition. The oper-

ating parameters to be displayed are selected in

interact ion w ith the operat ing personnel accord-

ing to ce rta in criteria. Aroun d 80%of operato r

input and monitoring during normal operation of

the plant ta kes place from these overviews.

Partial replacement of alphanumeric displaysw ith ana log displays, hybrid displays (analog and

sta tus display), a nd t rend representa tions.

Reduct ion in the comp lexity of t he process flowdiagrams thanks to task-oriented and process-

status-oriented selection of the process values to

be represented (dedicated representat ions for

start-up and shutdow n, normal operation, loa d

change, and diagnostics)

Use of a co lor scheme including a larm colors Process picture representations as a component

in organizing the operator console

Representat ion o f informat ion instead of dat a,e.g. innovative representat iona l objects for tem-

perat ure distributions, or trend curves for assess-

ing situa tions and deciding on o perating strate-

gies

System solutions:

Multifunctional integrated o perator w orkstat ionwith homogenous operator interface, operator

cont rol w ith the sam e input/out put devices

Applications of all individual devices in accor-dan ce w ith a device-w ide style guide for process

visualization

Configuration of the operator wo rkstat ion a spart of t he organization of the operator console

Ergonomic design of the o perator w orkstation Design of the control room as the living space for

the operators

Measures in the concept and design phase:

Specify the process visualization co ncept in thestyle guide of the process visualization system

Integrate the users (operating personnel) intothe design process at an early stage. If this is not

possible, the a bstract representa tions must be

created later in the optimization pha se

Involve experts w ith process know -howThe concept is based o n t he rules a nd recommen-

dat ions f ur the structure of d isplays whe re screen

systems a re u sed for process control listed in

VDI/VDE 369 9 "Pro cess con t rol using displa y

screens" [4].

The recommen dat ions in tha t docum ent a re con-

tinued in this concept and placed in the context ofuser-centric process visualization.

3. Display and operator con-trol concept using the exam-ple of a batch column

The conc ept described in th e previous section is

explained below using the example of a distillation

column.

The t asks of the o perato r of a distillat ion columnare:

Starting up and shutting dow n the distillat ioncolumn

Monitoring the process-relat ed cha racteristicvariables, e.g. differential pressure

Respond ing to cha nge s in pressure (fract ionchange) at the head of the column

Responding to alarmsThese t asks are ta ken into accoun t in the display

and o perator control concept to gua rantee an o pti-

mal w orking environment for the o perator.

An overview d isplay is selected for mo nitoring the

process-relate d cha racteristic values. This cont ains

the important process values and closed-loop con-

trols of the column. This display has the a dvan ta ge

tha t large volumes of data can be combined for the

condensed presentation of informat ion.


7/9



Fig. 2: Overview diagram of the column

The t ask "monitoring t he he ad pressure" is effec-

tively supported by a trend display on the o perator

screen. At a const ant hea d tem perature (T1001),

the hea d pressure (P1002) drops sign ifican tly wh en

changing from one fraction to the next. The opera-

tor must respond to this by chang ing t he draw -off

tank.

The ta sk "monitoring t he differential pressure",

especially following a fraction change, is supported

by a trend display showing the permissible toler-

ance ba nd. The d ifferential pressure (P1003) is a

mea sure of the g as load in the column and must be

kept approxima tely const an t. This is w hy the o pti-

mal working range is represented in the trend dis-

play.

Other important characteristic variables repre-

sented include the energy consumption o f the plant

and the reflux ratio.

New hybrid displays enable the evaluation of the

process values. These visua lize t he accepta ble

range for the process value. Otherwise, evaluation

using an ana log value wo uld be possible only w ith

experience.

Fig. 3: New hybrid display

Anothe r exam ple of eva luating process va riab les isthe representa tion of the temperatures in the col-umn.

Evaluating t he process stat us using t he tempera-tures as ana log va lues can only be done w ith expert

know ledge (cf. Fig. 4; a re the temperat ures w ithin

the optimal wo rking range?).

Optimal Operating Range

Prozess Value with Measure

(Visualization of an Alarm)

Alarm Indication

Alarm (High Limit)


8/9



Fig. 4: Typical view of a distillation co lumn

If the temperatures are instead visualized as a

temperature curve showing the o ptima l wo rking

range, the evaluation can be do ne via the picture.

(cf. Fig. 5; o ne tem perature is not in the optimal

wo rking rang e).

Fig. 5: View o f a distillation co lumn with vertical tempe rature

curve

4. Conclusion

The su gg ested user-centric visualizat ion co ncept is

intended as a holistic solution approach for effec-tively coping w ith the increasing complexity of th e

processes to be monitored and the working envi-

ronment in cont rol rooms f rom the o perator's per-

spective.

Many aspects justify investment in modern human

ma chine interf aces or call for redesigning of t radi-

tional operator control concepts: safe operation of

production plants through avoidance of operator

errors, extension of operator tasks, loss of operat-

ing know-how through fluctuations in employee

numbers, and , not least, increased w ork load result-

ing from t he merg ing of cont rol roo ms. Initial ex-periences in application argue in favor of the use of

these concepts.


9/9



Bibliography

[1] NA 120 "Operato r Workplace from the Human -Process Commun ication Point of

View "

[2] Wickens, C.D., Hollan d, J.G. (2000). Eng ineering psycholog y and human perform-

an ce. New Jersey: Prentice Hall.

[3 ] EEMUA 20 1 PROCESS PLANTCONTROL DESK UTILISING HUMAN-COMPUTER IN TER-

FACES - A Guide t o Design, Opera tiona l an d Huma n-Compute r Interf ace

Issues

[4] VDI/VDE 3699 "Process con trol using display screen s"

[5] Charw at , H.J. Lexikon der Mensch-Maschine Komm unikation

(Lexicon of human machine comm unication)

www.siemens.com

All rights reserved. All trademarks used

are ow ned b y Siemens or their respective ow ners.

Siemens AG 2012

Siemens AG

Siemensa llee 84

76157 Karlsruhe

modern plant control centers and operator control concepts_k1

Documents