Maximize Operator Effectiveness papers... · the ISA-101 HMI Standard released in August 2015. HPHMI Work Processes and Implementation Guidance: The work process for HMI improvement

Maximize Operator Effectiveness:

High Performance HMI Principles and Best Practices

Part 1 of 2

A PAS White PaperVersion 3.0

Bill HollifieldPrincipal Alarm Management and HMI Consultant, PAS

Hector PerezHMI Product Manager, PAS

High Performance HMI 3.0 - Part 1 | Cover© PAS Global, LLC 2017

Table of Contents

High Performance HMITM | Table of Contents© PAS Global, LLC 2017

Introduction and Overview ......................................................................................................................................................... 1

HMIs Past and Present ………………………………………………….................................................…....…………...................................... 3

Justification for HMI Improvement .......................................................................................................................................... 5

Proper Graphic Principles ........................................................................................................................................................... 6

Show Information Instead of Raw Data ................................................................................................................................. 7

Proper Use of Color ....................................................................................................................................................................... 9

Elements and Depictions of HPHMI ........................................................................................................................................ 10

Depicting Process Values ......................................................................................................................................................... 10

Depicting Alarms ......................................................................................................................................................................... 11

Depicting Profiles of Temperature or Pressure ................................................................................................................ 13

Depicting Dynamic Equipment .............................................................................................................................................. 13

Bars vs. Pointers .......................................................................................................................................................................... 14

Depicting Level Indication ....................................................................................................................................................... 14

Depicting Control Valves and Shutoff Valves ................................................................................................................... 14

Depicting Equipment Commands ........................................................................................................................................ 15

Use of Trends ................................................................................................................................................................................ 16

Depicting Tables .......................................................................................................................................................................... 16

Depicting Advanced Process Control (APC) .................................................................................................................... 17

Depicting Shutdown Activation ............................................................................................................................................ 17

Depicting Interlock Functionality ......................................................................................................................................... 18

Startup Map ................................................................................................................................................................................... 20

Navigation and Command Buttons ...................................................................................................................................... 20

Display Layout and Faceplate Handling ............................................................................................................................. 21

Avoiding “Blob” Graphics ......................................................................................................................................................... 23

Display Hierarchy ......................................................................................................................................................................... 23

Level 1 – Operation Overview ................................................................................................................................................. 24

Level 2 – Unit Control ................................................................................................................................................................ 25

Level 3 – Unit Detail .................................................................................................................................................................... 26

Level 4 –Support and Diagnostic Displays ........................................................................................................................ 26

Conclusion of the Part 1 Document ...................................................................................................................................... 27

About the Authors ...................................................................................................................................................................... 28

References ..................................................................................................................................................................................... 29

High Performance HMI 3.0 - Part 1 | Page 1© PAS Global, LLC 2017

Introduction and OverviewThe process control and automation industry has spent billions on improving process safety

via complex, instrumented systems. Yet, we continue to frequently see industrial incidents,

accidents, and fatalities in the news. The causes are generally not the failure of such automated

systems, but are instead the result of a wide variety of human errors. PAS firmly believes that

addressing the causes of human error and the improvement of Operator Effectiveness is of

the highest importance. The proper use of such technologies as High Performance HMI and

Alarm Management can actually save lives and prevent injuries. Detailed information on these

should not be withheld, and that is why we offer this and other white papers freely. They can

also significantly lessen process upsets, improve process efficiency, and increase productivity.

The human-machine interface (HMI) is the collection of screens, graphic displays, and other

technologies used by the operator to monitor and interact with the control system (typically

DCS or SCADA). Several major accidents, such as the Texas City refinery explosion in 2005,

have cited poor HMIs as a significant contributing factor. The design of the HMI plays a critical

role in determining the operator’s ability to effectively manage the operation, particularly in

quickly detecting and resolving an abnormal situation, which is the most important task of an

operator. A poor HMI can actively interfere with this ability.

For several reasons, the current designs and capabilities of most HMIs are far from optimal

for running the kinds of complex operations we have in industry. Most HMIs consist simply of

schematic or P&ID style graphics covered in numbers. Such displays provide the operator large

amounts of raw data, but almost no real information. They are difficult to interpret and provide

inadequate situation awareness to the operator.

Since we published The High Performance HMI Handbook in 2008, improving HMI has become

on of the hottest topics in the automation industry. In that book, we explained exactly why

most current HMI practices were poor, and we put forth the proper principles and details for

making graphics significantly better. Many companies have adopted those principles and have

completed migrations to improved graphics. Many more have such efforts currently underway.

This two-part paper provides a history, justification, and detailed plan of action for the

improvement of a process control HMI. Here is an overview of the contents.


Part 1Examples: We provide typical examples of common but poor HMIs, along with highly

detailed depictions of improved methods that provide for much better operator situation

awareness and control.

Principles: We cover the most important aspect of High Performance HMI™ (HPHMI),

the display of information to the operator rather than raw data. Many other necessary

graphic principles including the correct way to use color are provided. Depictions of

detailed graphic elements are included.

Hierarchy: HPHMI graphic designs must reflect a proper hierarchy – the exposure of

additional detail as needed. We include examples of graphics that illustrate this hierarchy,

along with the work processes used to design such graphics.

If your facility utilizes a process control system with a computer-based HMI, you will find this

information useful. This white paper augments the detailed content in The High Performance

HMI Handbook.

Part 2 (Separate Document)Case Studies: Since the publication of our 2008 book, many projects have provided

for the development of real-world case studies. We include two such studies in this

paper. The first was conducted by the Electric Power Research Institute (EPRI), but is

applicable to all types of process operations. The second shows how a major company

has improved performance and significantly lowered costs via company-wide adoption

of standardized High Performance graphics. This has led to a major HPHMI product

innovation for the power industry: PowerGraphiX®.

We also provide an example as to how “out-of-the-box thinking” can address HMI issues,

in the discussion of a Pipeline System Overview Display.

Standards Review: Two standards documents available on HMI are discussed, including

the ISA-101 HMI Standard released in August 2015.

HPHMI Work Processes and Implementation Guidance: The work process for HMI

improvement is described. We also address the most common issues encountered in

HMI improvement, and cost effective ways to transition to High Performance graphics.


HMIs Past and PresentBefore the advent of sophisticated digital control systems, the operator’s HMI usually consisted

of a control wall concept such as Figure 1.

The control wall had the advantages of

providing an overview of the entire operation,

key trends, and a limited number of well-defined

alarms. A trained operator could see the entire

operation almost at a glance. Spatial and

pattern recognition played an important role

in the operator’s ability to detect burgeoning

abnormal situations.

These systems had several disadvantages.

They were difficult to modify, the addition of

incremental capabilities was problematic, and

the ability to extract and analyze data from

them was almost non-existent. In the 1980s-1990s, the modern electronic control systems (DCS/

SCADA) replaced them for such reasons.

When the modern systems were introduced, they included the capability to create and display

graphics for aiding in the control of the operation. However, there were no guidelines available

as to how to create effective graphics. Early adopters created graphics that mimicked P&ID or

schematic drawings, primarily because they were readily available. The limited color palette was

used inconsistently, and screens

began to be little more than

crowded displays of numbers on

a P&ID.

Graphics such as Figures 2

and 3 were developed over 20

years ago and remain common

throughout the industry. Indeed,

inertia, not cost, is the primary

obstacle to the improvement of

HMIs. Engineers and operators

become accustomed to this style

of graphic, and are resistant to

change.

Figure 1: Example of a Control Wall

Figure 2: An Early Graphic Showing Many Problematic Practices


As a result, industries that

use modern control systems

are now running multi-

million dollar operations

from primitive HMIs created

decades ago at a time that

little knowledge of proper

practices and principles was

available.

As control system hardware

progressed, the manufacturers

began to develop very flashy

example graphics which were

used for marketing purposes. While fit for that purpose, they were quite ineffective for actually

controlling a process. Many companies and projects, however, began to create graphics similar

to those examples. The results were displays that are actually suboptimal for operators.

To illustrate this point, Figure 4 is an example of flashy design taken from a power generation

facility. The graphic dedicates 90 percent of the screen space to the depiction of 3-D equipment,

vibrantly colored operation lines, cutaway views, and similar elements. However, the information

actually used by the operator consists of poorly depicted numerical data, which is scattered

around the graphic, and only makes up 10 percent of the available screen area.

There are no trends, condition

indicators, or key performance

elements. You cannot easily

tell from this graphic whether

the operation is running well

or poorly. That situation is true

for more than 90 percent of

the graphics used throughout

industry today because

they were not designed to

incorporate such information.

Instead, they simply display

dozens to hundreds of

raw numbers lacking any

informative context.

Figure 3: A Typical Crowded, P&ID-Style Graphic

Figure 4: A Flashy Graphic Inappropriate for Actual Operational Control


Justification for HMI ImprovementPoorly performing HMIs have been cited time and again as significant contributing factors to

major accidents. Yet, our industry has made little significant change in HMI design. There is

another industry that learns from its accidents and has made phenomenal advancement in HMI

design based on new technology. That industry is avionics. The resulting improvement in pilot

situation awareness is one of the largest contributing factors in the decades-long decline in

aviation accidents.

Modern avionics feature fully-integrated electronic displays as shown in Figure 5. These depict

all of the important information, not just raw data, needed by the operator (i.e., pilot). Position,

course, route, engine diagnostics, communication frequencies, and automated checklists are

displayed on moving maps with built-in terrain proximity awareness. Real-time weather from

satellite is overlaid on the map. Detailed database information on airports is available with just a

click. Situation awareness and abnormal situation detection is far improved by these advances.

This capability – impossible even a dozen years ago in multi-million dollar airliners – is now

standard on even the smallest single engine aircraft.

There have been tests involving actual operators running realistic simulations using traditional

graphics vs. High Performance ones. PAS participated in such a test at a large power plant,

sponsored by the EPRI and detailed later in this paper. The results were consistent with a

similar test run by the ASM® (Abnormal Situation Management) Consortium on an ethylene

plant. The test showed the High Performance graphics provided significant improvement in the

detection of abnormal situations (even before alarms occurred) and significant improvement in

the success rate for handling them. In the real world, this translates into a savings of hundreds

of thousands of dollars per year.

Since safety is significantly improved with modern HMIs, it is only logical that we would want all

operators to have access to them. Yet most companies have done little to upgrade.

Figure 5: Garmin G2000® Avionics Package in a Small Plane


Proper Graphic PrinciplesIneffectively designed graphics are easy to find. Simply search the internet for images under the

category “HMI.” Problems with these graphics include:

● Primarily a schematic or P&ID representation

● Lots of displayed numbers

● Few or no trends

● Spinning pumps/compressors, moving conveyors, animated flames, and similar distracting elements ● Brightly colored 3-D equipment ● Highly detailed equipment depictions ● Attempts to color code piping with contents ● Long, cryptic tagnames shown on the screen

● Brightly colored liquid levels displaying the full width of the vessel

● Lots of crossing lines and inconsistent flow direction

● Inconsistent color coding ● Bright colors on dark backgrounds ● Misuse of alarm-related colors ● Limited, haphazard navigation ● A lack of display hierarchy

Ineffective graphics encourage poor operating practices, such as operating by alarm. By

contrast, High Performance graphics have:

● A generally non-schematic depiction except when functionally essential

and at Level 3

● Limited use of color, where color is used specifically and consistently

● Gray backgrounds to minimize glare and reflection issues

● No animation, except for specific alarm-related graphic behavior ● Embedded, properly-formatted trends of important parameters ● Analog representation of important measurements, including their value

to normal, abnormal, alarm, and interlock conditions ● A proper hierarchy of display content providing for the progressive exposure

of detailed information as needed

● Simple and straightforward depictions in 2-D not 3-D ● Consistent flow depiction and layout to minimize crossing lines ● Embedded information in context (via right-click menus or similar methods) such

as alarm documentation and rationalization, standard operating procedures, and

more. ● Logical and consistent navigation methods ● Techniques to minimize operator data entry mistakes ● Validation and security measures


Show Information Instead of Raw DataA primary difference of High Performance graphics is the underlying principle that, wherever

possible, operational values are shown in an informational context and not simply as raw

numbers scattered around the screen.

As an example, consider this depiction of a

compressor shown in Figure 6. Much money has

been spent on the purchase of instrumentation.

Yet, unless you are specifically trained and

experienced with this compressor, you cannot

tell if it is running at peak efficiency or is about

to fail.

The mental process of comparing each

number to a memorized mental map of

“what is good” is a difficult cognitive process.

Operators have hundreds (or even thousands)

of measurements to monitor. Thus the results vary by the experience and memory of the

operators, as well as how many abnormal situations they have personally experienced with this

particular compressor. Training new operators is difficult because the building of these mental

maps is a slow process. Adding more numbers to a screen like this one does not aid in situation

awareness; it actually detracts from it.

By contrast, a bank of analog indicators, as in Figure 7, can represent these numbers much more

effectively. Analog is a powerful tool because humans intuitively understand analog depictions.

Information is data in context made useful.

Figure 6: All Data, No Information

West East

Drive: 232.2 amps

Cooler

W. Vibration: 2.77 E. Vibration: 3.07

2.77MSCFH

155.2 °F 108.2 °F 166.1 °F55.7 psig

135.1psig

190.5 psig

Oil 155.2 °FOil 85.1 psi

65.1 °F

Figure 7: Analog Depiction of Information

Coolgpm

RECYCLE COMPRESSOR K43

Alarm Indicator

Desirable Operating Range

AlarmRange

AlarmRange

Suctpsig

Interpsig

Dschpsig

SuctdegF

InterdegF

DschdegF

E. Vibmil

N. Vibmil

W. Vibmil

MotorAmps

Oilpsig

OildegF

Interlock Threshold

42.7 38.7 93.1 185 95 120 170 12 8 9 170 80 290

2


We are hard-wired for pattern recognition. With a single glance at this bank of properly designed

analog indicators, the operators can tell if any values are outside of the normal range, by how

much, and the proximity of the reading to both alarm ranges and the values at which interlock

actions occur. Analog depictions such as these moving analog indicators are a key element of

HPHMI.

In just a second or two of examination, the operator knows which readings, if any, need further

attention. If none do, the operator can continue to survey the other portions of the operation.

In a series of short scans, the operator becomes fully aware of the current performance of their

entire span of control.

The knowledge of what is normal is embedded into the HMI itself, making training easier and

facilitating abnormal situation detection – even before alarms occur, which is highly desirable.

Similarly, depiction of PID controllers is accomplished with the addition of easily scanned

setpoint, mode, and output information, as in Figure 9. If the final control element has a position

feedback signal, deviation is easily and effectively shown on the output scale. Mechanical

deviations are prime causes of abnormal situations, and they should be made easy to spot.

The subtle, slight gradients and shadows are intended to increase prominence of the live

elements. Images in printed form are often significantly different than images shown on a

screen. For that reason, other modifications to increase printed visibility have been made on

some depictions in this paper. Actual design of HPHMI elements concerns their appearance on

the screen.

Figure 8: Further Explanation of Moving Analog Indicators

FLOWgph

Desirable Operating Range shown as a light blue shaded area

Hi-Hi Alarm Range

Low Alarm

Abnormal High Range

Abnormal Low Range

32.1

Moving Analog indicators with Normal Range, High, Hi-Hi, Low, and Lo-Lo alarm indications, Interlock indication, and recent range

Hi Alarm Range

Lo-Lo Alarm

FLOWgph

81.1

FLOWgph

91.1

Priority 3Hi Alarm is in effect

Priority 2 Hi-Hi alarm is in effect and Hi Alarm is still in effect

Alarm indicator is always based on the highest priority alarm in effect on the sensor

FLOWgph

Dark blue bar shows measurement variability in a specified time period such as prior 2 hours. (possible on some control systems)

63.5Interlock Function

When Measurement

Is Invalid

----BAD

43 2


Proper User of ColorColor must be used consistently. People have several types of common color-detection

deficiency (e.g., red-green, white-cyan, green-yellow). For this reason, the most important rule

for color is this:

Color, by itself, is never used as the sole differentiator of an important condition or status.

Most graphics throughout the world violate this principle. A color palette must have a limited

number of distinguishable colors used consistently. Bright colors are primarily used to bring

or draw attention to abnormal situations, not normal ones. Screens depicting the operation

running normally should not show brightly saturated colors, such as bright red or green pumps,

equipment, valves, and similar items.

When alarm colors are chosen, such as bright red and yellow, they are used solely as an aspect

of the depiction of an alarm-related condition, and for no other purpose. If color is used

inconsistently, then it ceases to have meaning. Figure 10 is a workable HPHMI color palette, and

the example figures in this paper generally follow it. There should not be very many colors, and

all colors must be easily distinguishable.

Graphics with color-neutral gray backgrounds on LCD screens are effective. They also enable

the lights in the control room to be turned back to bright – where they should be. Poor graphics

began with dark backgrounds and bright colors due to 1980s-90s CRT hardware limitations.

This scheme resulted in major glare and reflection problems, which were addressed by dimming

the control room lights. For operator alertness, the control room lighting should actually be

brighter than a typical office, all day and all night.

Controller with Device Feedback

562.1AUTO560.0

22%23%

With Position Deviation Alarm

602.1AUTO485.0

22%55%

A A A A M A A AA B C D E F G H

Damper Position

7473

77 78

45 78

74 75

50 51

50 50

75 65

5155

2

22

DescriptionUnits (psig)

PV, Mode, Setpoint & OutputValues

Diamond for Setpoint

Output Indicator0-100%

Black Outline Indicates Mode is Abnormal

Analog Controller Depiction

562.1MAN560.022%

Device Feedback on same scale

Figure 9: Analog Depiction of PID Controllers and Position Feedback


Elements and Depictions of HPHMIThis section shows many of the common situations that a process graphic must depict, and how

to accomplish those depictions by following High Performance HMI principles.

Depicting Process ValuesThe display of live values on the screen should be shown in a different way than static text:

● The choice of a bold, dark blue is a good choice with the gray background, and

differentiates live values from static text done in black or dark gray as in Figure 11.

● Leading zeros are not displayed, except on fractional values (e.g., 0.27). Values are

shown only to the precision needed by the operator.

● In tables or columns, generally align numbers on the decimal point.

● Units of measurement are displayed in non-bold text near the value.

Figure 10: An Example HPHMI Color Palette

Color RGB Values Sample Defined Uses

Gray 213, 213, 213 Overall graphic background

White 255, 255, 255 Highlighting of some small items, e.g., PV Quality indications

Light Gray 243, 243, 243 ON indication for equipment

Gray 136, 136, 136 Off indication for equipment

Dark Gray 74, 74, 74 Some text, minor process lines

Black 0, 0, 0 Text and labels, major process lines, process vessel outlines. Dark Gray (64, 64, 64) can also be a good choice.

Dark Blue 0, 0, 215 Process values, controller modes and outputs, similar special purposes. Trend line for a single trended value.

Dark Green 0, 128, 0 Controller setpoints and other operator inputs, trend trace of setpoints

Light Green 153, 255, 102 Possible “faint green” for some specific highlighting

Light Blue 187, 224, 227 Desired operating ranges or conditions

Cyan 0, 255, 255 Vessel level strips, trend lines

Brown 204, 102, 0 Trend lines, position feedback indiciation

Pale Red (Pink) 255, 153, 204 Possible “faint red” for some specific indications

Red 255, 0, 0 Top level, priority one alarm

Yellow 255, 255, 0 Priority two alarm

Orange 255, 102, 0 Priority three alarm

Magenta 255, 0, 255 Priority four alarm for diagnostics

Dark Magenta 204, 0, 102 Trend lines


● Point names should not be shown on the screen by default. It should never

be necessary for an operator to have to type in a point name in the entire HMI.

● Process values can have a variety of diagnostic conditions. Figure 11 shows a clear,

concise, and visible way for depicting those. Color coding is not recommended.

● When items are “selected”, that status should be indicated. Surrounding the

selected item with a white outline is a good practice.

Depicting Alarms Proper alarm depiction should also be redundantly coded based upon alarm priority

(color / shape / text). Alarm colors should not be used for non-alarm related functionality.

When a value or object comes into alarm, the separate alarm indicator appears next to it, as

shown in Figure 12. The indicator flashes while the alarm is unacknowledged (one of the very

few proper uses of animation) and ceases flashing after acknowledgement, but remains visible

as long as the alarm condition is in effect. People do not detect color change well in peripheral

vision, but movement such as flashing is readily detected. Alarms thus readily stand out on a

graphic (and on multiple screens) and are detectable at a glance.

Figure 12 shows that the most common methods of alarm indication are a direct violation of the

basic rule of color use, as they are different solely by the use of color.

Figure 11: Depicting Process Values

480.1 psi

480.1 psi

Invisible selection area

480.1 psi

Selection indication

Normal

Display of process values. No alarm conditions are in effect.

480.1 psi

Bad or Out of Range Value

?LG

Note that the BAD or OOR condition is normally alarmed, and the additional alarm element would be shown (see depiction of alarm conditions).

It may be possible to show the Last Good Value of a BAD or OOR measurement, rather than showing dashes. If this is the case, the depiction will be:

----- psi

Bad Value

----- psi

Out of Range

BAD OOR

Vent ValveAutoMoving Locked

Damper 7: SW 66:

ClosedStoppedPump 14:

Discrete (“digital”) conditions are shown using the same blue color and in bold, using easily understood words

Selection of an item causes the relevant faceplate to appear and the selected item is highlighted. See Faceplate section.


It is highly beneficial to include access within the HMI

to the alarm rationalization information contained in

the Master Alarm Database as show in Figure 13. If

these terms are unfamiliar, you are advised to read

the ISA 18.2 standard for Alarm Management in the

Process Industry, or read the API RP-1167 Alarm

Management Recommended Practice if you are in

the pipeline industry. PAS offers free white papers

explaining both documents.

Figure 13: Linked Alarm Information

Information called into the shape & size of a standard faceplate

Link to Procedures

Right-click callup

Embedding Alarm Documentation

Off spec ProductionLowered efficiency

Category: Minor FinancialPriority: 3Setting: 120 deg FResponse Time: <15 min

Adjust reflux per computation; check Controller for cascade mode.Check feed composition

SOP 468 -1

Adjust base steam rate.Check pressure and feed parameters vs.

Excess steamPressure excursionInsufficient refluxFeed composition variance

TI-468-02 ColumnOverhead Temperature

-

122.1 deg F

X

Corrective Actions:

Alarm Causes:

Alarm Consequences:

Alarm: PV HIGH

3

Figure 12: Depiction of Alarms

Diagnostic Priority

Priority 3 Priority 2 Priority 1

480.1 psi 480.1 psi 480.1 psi480.1 psi

Diagnostic Priority


psi psi psipsi 480.1480.1 480.1 480.1

480.1 psi

No Alarm

480.1 psi

In Alarm

SimilarBadDepictions

480.1480.1480.1

480.1 psi

In Alarm

The symbol’s outlines above are important! Symbols without them would not be as effective in standing out on a graphic:

Priority 4Diagnostic


480.1 psi 480.1 psi 480.1 psi480.1 psi

2 1

4 3

4 3 12

SuppressedAlarm 480.1 psi

S

Poor Alarm Depictions Violating the Basic Color Rule

Improved Alarm Depictions With Redundant Coding

Total 4 8 1 120

0 2 10

Alarms

Un-Ack

Overall Alarms Summary element

432 S1


Depicting Profiles of Temperature or PressureConsider these alternative distillation column

temperature profile displays. When only numbers

are shown, even an experienced operator may easily

miss a suboptimal condition. Additionally, a new

operator will find it difficult to build a mental map

of a proper profile. The desire is for all operators to

recognize normal and abnormal profiles at a single

glance.

A correct profile can be seen at a glance as a

straight line.

Depicting Dynamic Equipment So what about the paradigm of using bright green to depict “on” and bright red for “off” (or

vice versa in the power industry)? This is an improper use of color. The answer is a depiction

such as Figure 15.

The relative brightness of the object shows

its on-off status, as does the use of a process

value word next to it. Equipment items

brighter than the background are on (think of

a light bulb inside them). Items darker than

the background are off. If equipment has no

status that is sensed by the control system, but

is desired on the graphic anyway, it is shown

as transparent to the background color. The

status word can indicate several conditions,

as shown. Remember, if any of those are also

alarm conditions, the separate alarm indicator

will appear next to the equipment when it is

in an alarmed state.

A Column Temperature Profile

Is this a good profile?

Too hot at the bottom, too cold

at the top.

20.1

24.2

25.6

27.8

28.9

20.1

24.2

25.6

27.8

28.9

Alarm Ranges

This one is.

Normalrange

18.2

24.0

25.6

29.8

32.9 2

Figure 14: Measurement Profile

Figure 15: Depicting Status with Redundant Coding

and Proper Color Usage

(Shape is Filled Darker)

Wrong Better

Pump Not Running

PumpRunning

Wrong Better

STOPPED

RUNNING(Shape is Filled Brighter)

Dynamic equipment without instrumentation sensing of process states can be depicted with a fill the same as the background.

RunningInterlocked

Stopped – ErrorStopped with ConditionStopped – Needs ResetStopped – OK to Start

Repair State

RunningInterlocked

Stopped – ErrorStopped with ConditionStopped – Needs ResetStopped – OK to Start

Repair State

Showing choices from predefined conditions

Running

Limiting the displayed conditions to only those in effect:

Stopped – Needs Reset


Bars vs. Pointers Attention to detail is important. It is typical to use bar graph elements to show relative

positions and values. While this may be better than simply showing numbers, it is inferior

to the use of moving pointer elements, since the bar disappears as the bar’s value gets low.

The human eye is better at detecting the presence of something than its absence. And, the

low condition may be more

important than the high

condition and should have

equal visual prominence.

The example in Figure 16 is

superior in showing relative

values, besides the color

improvement.

Depicting Level Indication Vessel levels should not be shown as large blobs of saturated color. A simple strip depiction

showing the proximity to alarm limits is better. A combination of trend and analog indicator

depictions is even better such as Figure 17. The right-hand edge of the trend replaces the pointer

and provides context.

Depicting Control Valves and Shutoff Valves Control valves turn out to be one of the more complicated items to depict. The tendency is

to want to cram too much data into a small space. Traditionally, we depict a control valve

(throttling, variable position) with a domed head depiction and an automated block valve (only

on-off) with a rectangular head depiction.

25% 50% 75%

ValveV-1V-2V-3X-1X-2X-3X-4S-1S-2K-1K-2

100%100%

95%88%

100%100%

75%0%

55%100%100%

100%0%

Analog Position - Better

25% 50% 75%

100%100%

95%88%

100%100%

75%0%

55%100%100%

100%0%

Analog Position – Poor but Typical

ValveV-1V-2V-3X-1X-2X-3X-4S-1S-2K-1K-2

Figure 16: Bars vs. Pointers

Poor Better: Thin bar level strip with

normal and alarm range

context

Very Poor

Crude Feed

-21

Trend with dotted lines for normal range, tic marks for

alarm settings

Best:Combination

with full context analog indicator

2 Hrs 81.5%

Depiction of Vessel Level Indication

2 Hrs 49.5%56.5%

TK

2

Figure 17: Vessel Levels


In keeping with equipment depictions, the valve body is filled darkly for closed and brightly

for open. This also follows the P&ID paradigm for block valves. The same method can depict

the state of three-way valves. The solenoid and position switch statuses can also be shown if

desired.

Depicting Equipment Commands When DCS/SCADA points are built that indicate equipment state, the control engineer can

usually decide which words to display to represent the current state. The choices they make

are often poor. The most common example is “RUN” and “STOP.” Do these represent the

equipment’s status, or a command to it? “RUNNING” and “STOPPED” are much better status

indication words. “STOP” and “START” are commands, not statuses.

Similarly, the graphics need to differentiate clearly between status indications and command

possibilities. In general, the graphic indicates the current state, and faceplate interactions are

used to command changes to that state. It is

common to have a point type that includes

both a switch-type (binary) output command

and binary status feedback, commonly called

a Digital Composite Point. Figure 19 shows a

compact graphic presentation of those statuses.

Selecting the graphic element would call up the

faceplate for the actual interaction.

Figure 18: Control and Automated Block Valves

Control Valves(no feedback)

Same Principles for On-Off Valves, with Status Words

ValveOpen

ValveClosed

33%

0%

TravOpen

Closed

Actual determines valve body fill.O% and A %

numbers are shown

O: 33%A: 38%

Control Valves(with Analog Feedback)

3-Way Valves Showing Open Flow Paths

Valve Head is Unfilled

Output determines valve head

Open

Closed

Output determines valve head

No feedback

FailOpen

0%

FailClosed

0%

FailLast

0%

Valve Traveling

Position Switches: Made and Unmade

Solenoid: When de-energized, valve moves to fail position

Showing All The Options: Confusing!

O: 100%A: 99%

Output % Shown

Valve Fail Direction

Avoid Tiny Output Bars!

If You Can’t Resist, at Least Use a Slider

Figure 19: Digital Composite Point Depiction

RunStopped

Pump 22

Digital Composite Point Depiction:Command (“setpoint”) to the device:Feedback from the device:

Mismatch alarm if applicable

3


Use of Trends The most glaring deficiency in HMI today is the general

lack of properly implemented trends. Every graphic

generally has one or two values on it that would be far

better understood if presented as trends. However, the

graphics rarely incorporate them.

Instead, engineers and managers believe vendor claims

that their operators can easily trend any value in the

control system on demand with just a click. This is

incorrect in practice; a properly scaled and ranged trend

may take 10 to 20 clicks/selections to create, and usually

disappears into the void if the screen is used for another

purpose (like calling up a different graphic).

This deficiency is easily provable; simply walk into the

control room and count how many trends are displayed.

Our experience in hundreds of control rooms is that

trends are vastly underutilized and situation awareness

suffers due to that.

Trends should be embedded in the graphics and appear, showing proper history, whenever

the graphic is called up. This is generally possible, but is a capability often not utilized. Trends

should incorporate elements that depict both the normal and abnormal ranges for the trended

value. There are a variety of ways to accomplish this as shown in Figure 20. The range indicator

could also indicate the alarm and interlock ranges (see the later Level 1 Overview Example;

Figure 33).

Depicting Tables Even tables and checklists can

incorporate proper principles as

shown in Figure 21. Consistent

colors and status indication can

be integrated. The intent is to

make the abnormal stand out.

Figure 20: Trend Depiction of Desirable Ranges

West Comp Discharge Temp °C

40.0

50.0

-60 -30-90 Hours2

West Comp Flow MSCFH

45.0

55.0

-60 -30-90 2 Hours- --

PV49.1SP

50.5

PV44.1

500015

1 Hr

Feed Water3280DrumLevel-0.5

MainSteam4150

0-10

Figure 21: Tables and Checklists

Abc abc abcAbc abc abcAbc abc abcAbc abc abcAbc abc abc

XXX

Better PracticeAbc abc abcAbc abc abcAbc abc abcAbc abc abcAbc abc abc

Improper PracticeBreaker 15 Power Oil Temp 16-33Oil Pres Status Level in TK-8776 Gen System Status Comp 88 in Auto Lineup Ready Sys Status Checks Bearing Readouts Comm check Outlet Temp < 250 Cooling Flow Internal Circuit Check Bypass Closed AFS Function

NOT OK

HPHMI Startup Permissives Table

Air Comp

Status Mode Diagnostic

C #1 RUNNING AUTO OK

C #2 STOPPED MAN OK

C #3 RUNNING AUTO OK

C #4 STOPPED AUTO FAULT

A2 CWP

B2 CWP

Pump Status

ON

ON

A2 HWP

B2 HWPON

OFF

C2 HWP

SUBFPON

ON

A2BFPT

B2BFPTON

ON

Another Better Practice Status Table

HPHMI Equipment Status Table

Table Design

2

3

OKNOT OK

NOT OKNOT OK

OFF

OKNOT OK

OK

OFFNOT OK

NOT OK

NOT OK

NOT OKNOT OKNOT OK

3


Depicting Advanced Process ControlAdvanced Process Control (APC) is also known as Multi-Variable Control. It is the method by

which a sophisticated computer program monitors the process and adjusts controllers in real

time to continually optimize performance.

Not all controllers are “touched” by the APC

system, and it is useful for the operator to see

which ones are, and what the APC system is

doing with them. Small indicators next to the

affected controllers are useful for this. Figure

22 shows this with an alternative, non-analog

PID controller representation that is useful in

some circumstances.

A Level 2 or 3 screen showing overall health

and functionality of the APC system itself is

desirable.

Depicting Shutdown ActivationOperators must have the ability to shut down operating equipment manually and quickly.

However, when an important action with significant consequences is based upon operator

input, the input should have a confirmation mechanism that avoids inadvertent activation. The

“cancellation” option should be consistently implemented.

It should never be possible to make a single selection on a screen that results in an inadvertent

shutdown. A “Shutdown button” should call up at least one and perhaps two layers of

confirmation before it is possible to actually cause such a significant event.

The “defaults” of such mechanisms should be

on the safe option. Always consider what an

inadvertent “ENTER” will do and label screen

items with full clarity.

Major process upsets have occurred by

mistyping an input (for example, opening a

slide valve to 47 percent instead of 4.7 percent).

Older DCSs using membrane keyboards are

particularly susceptible to this type of error.

Error checking methods should be used to

require confirmation of numerical entries that

seem inappropriate.

Figure 22: Advanced Process Control

APC

APC APC APC

APC is ON: Indicators for increase, decrease, and maintain:

APC in effect on a controller:

Simplified Alternative

APCAPC is Off: X X

Advanced Process Control (APC)

PSOAuto

77.088.5 %

TK21 Level75.1 %

Screen button selection calls

up a confirmation faceplate.

“Cancel” is the default:

“Continue” brings

up standard Digital Output

Faceplate:

SHUTDOWN

REACTOR7

Reactor 7Manual

Shutdown

CONTINUE

ACCESSReactor 7 Manual

Shutdown Switch

CANCELReactor 7Manual

Shutdown

CANCEL

X

Normal

DownShut

Screen button selection calls

up a confirmation faceplate.

“Cancel” is the default:

“Continue” brings

up standard Digital Output

Faceplate:

SHUTDOWN

REACTOR7

Normal

DownShut

Reactor 7Manual

Shutdown

CONTINUE

CANCEL

ACCESSReactor 7 Manual

Shutdown Switch

CANCELReactor 7

ManualShutdown

Shut Down

Normal

Reactor 7Shutdown

Figure 23: Layers of Confirmation


Depicting Interlock FunctionalityInterlocks are functions whereby normal

control actions are overridden by

predetermined process conditions. An

example would be to override a steam valve

to the closed position if the equipment

temperature or pressure is too high.

There are several HMI-related issues to be

addressed for interlocks, and these must be

handled regardless of whether the interlock

is implemented in the DCS or in a separate

Safety Instrumented System.

Interlocks are implemented using logic structures – usually “blocks” or “points” or “ladders.”

These are usually complicated and cryptic to understand, when displayed using the native

capabilities of the DCS (e.g., logic point detail). They may activate infrequently, since they are

usually designed to protect against an abnormal situation. Due to this, the operator may not

encounter them for months. When they activate, the operator may not remember being told

about “the new column interlock” implemented a year ago, and have no idea why he cannot

start feed to the column. If this occurs at 2 a.m. on a Saturday night, then the engineer is

(deservedly) likely to get a phone call and production may be delayed.

Therefore every interlock, when activated, needs to indicate that activation on the appropriate

Level 2 and 3 display. The strategy

may be different for those displays.

For Level 2 displays, a small bank of

interlock symbols can be created,

with functionality as shown in

Figures 24 and 34. An element next

to it can indicate the interlock action

conditions. When an interlock

becomes active, any element that

it is affecting (such as a pump

or control valve) should have the

interlock symbol appear next to it.

In this manner, the operator can

clearly see which interlocks are

in effect and what items they are

affecting.

Interlock in Effect

I

Interlock in Bypass

Interlock Not in Effect

I-57D I-57D I-57D

I

I I-5A I-5B I-5C

I-5D

I I

I I-5EI I-5FI

Feed ADTV-1 ADTV-2

Temp Pres Level

Interlock Actions:Stop Feed Stop ADTV-1Stop ADTV-2Max CoolingMax Vent

OFFOFFOFFOFFON

Interlock Symbology

Bank of Interlocks, Status and Actions

I

Figure 24: Interlock Symbology

Figure 25: Interlock Before and After Activation

Main Feed

I-57D

II-57D

Main Feed

Interlock DepictionPre-Alarm has occurredController is in Auto and block valve is still Open

Interlock DepictionPre-Alarm still in effect. Interlock has Activated with alarm. Controller is overridden to Manual and both valves are Closed

PSOAuto

110.052.0 %

Feed1 Flow108.5 gph

Open Open

Closed Closed

PSOMan

0.00.0 %

Feed1 Flow0.0 gph

D-101

D-101psig

D-101psig

I

D-101

202.0

222.0

2

2 2


For Level 3 displays, a more

detailed view of the interlock can

be shown such as in Figure 26.

When active, the specific interlock

symbol can be displayed next to

each initiator signal and affected

output. For Level 3 displays, an

interlock diagnostic element

should be created, clearly

showing the possible initiators

and possible actions taken by the

interlock. This does not have to

be complicated; a table such as

the following can often suffice.

When an interlock shuts down a piece of equipment, a first-out indication is often desirable

since some of the other initiators may activate after the shutdown trip occurs. Figure 27 is a

simple example of a Shutdown “First Out” Table:

Shortly after the compressor shuts down due to high vibration, the oil pressure also drops,

which produces another shutdown initiator. As a result of equipment isolation, the suction

pressure may also drop sufficiently to activate another shutdown initiator. Thus by the time the

diagnostic graphic is consulted, three separate shutdown causes are present and the question

is – which is the original culprit? Two are a consequence of the immediately prior shutdown, and

the actual cause of the shutdown is shown via the “First Out.” The vibration reading depicted is

“currently” much less than the shutdown limit (since it quits shaking after the shutdown), thus

the high vibration indication (the “X”) needs to be latched until reset.

West Compressor Interlock Initiators

Comp in Overspeed

Winding Temp is High

Vibration is High

1 Stg Pres is High

2 Stg Pres is High

Suction Pres is Low

Oil Pres is Low

NO

NO

NO

I W-1A W-1B W-1CI IMech Flow Pres

NO

YES

YES

Total Flow is Low NO

NO

West Compressor Interlock Actions

W. Comp Shutdown

Inlet Block Valve

Outlet Block Valve

Flow Cascade to Manual

Maximum Flow Bypass

Maximum Cooling

E. Comp Override to 100%

NO

OPEN

OPEN

NONORM

OFFWinding Purge

YESOPEN

Figure 26: Interlock Diagnostic Table

Figure 27: Shutdown Initiator Table with First Out

Compressor 43 Shutdown Initiators

West VIB >25

West Bearing Temp >220

East VIB >25

East Bearing Temp >220

Suction Pressure <20

Discharge Temp >240

Oil Pressure <10

Overspeed OK

160.3

1.3

155.3

12.3

148.7

3.3

1.5 First OutX

X

X


Startup MapInterlocks are functions whereby

normal control actions are overridden

by predetermined process conditions.

An example would be to override a

steam valve to the closed position if the

equipment temperature or pressure is too

high. There are several HMI-related issues

to be addressed for interlocks, and these

must be handled regardless of whether

the interlock is implemented in the DCS

or in a separate Safety Instrumented

System.

Navigation and Command ButtonsMultiple methods of navigation should be provided. The operator should be able to go up and

down through the hierarchy, side to side through the process, and call related details, trends,

and shutdown status displays from any graphic. This navigation capability should work with

all available methods provided by the DCS vendor – mouse or touch screen target selections,

keyboard keystrokes, context sensitive menus, or others.

Every screen (particularly Level 2) should have navigation targets to the most likely other screens

that the operator would access. When a P&ID depiction is used, any process line entering or

exiting the screen should contain a navigation link to the relevant graphic. Navigation buttons

or targets should be consistent and simple (and not look identical to command buttons).

Most control systems provide pre-made navigation button objects, including many that are

inappropriately colored, needlessly 3-D, and overly intrusive.

The system and graphics should be configured so it is never necessary for the operator to

type in a point name or graphic name. Some DCSs have arrays of programmable keys, which

can be assigned to call up certain

displays or combinations of

displays. For systems that do

not, programmable key arrays

are inexpensive on the computer

accessory market.

Figure 28: High Performance Element Designed for Startup Use

Reactor 7 Startup

0

+30 +60 +90

20

40

60

80

0

5

10

15

20

0

2

4

6

8

TempDeg C

FeedRateMPH

AdditiveFlowMPH

65.1

21.1

6.9

Tank Farm 2

Non-navigation depiction

Navigation Buttons Faceplate or Special Purpose Element Callup Buttons

NavigationTarget

ScrubberMain Menu

L2 Reactor M5

L2 Feed System

L3 M5 Agitator

L3 Analyzers

Pres Control

APC

Product Change

Feed Change

Figure 29: Navigation Buttons and Targets


Implementing an entire navigation structure in a single windows-type pull-down hierarchical

menu (i.e., one with “sub-menus” that pop-out of the side) is generally not recommended,

particularly a structure more than two levels deep.

The Main Menu: It is desirable for the operator to have two-click access from any graphic to any

other graphic, to supplement any other navigation method used. Every graphic should have a

consistently placed “Main Menu” navigation button. It opens a simple text screen, logically and

hierarchically arranged, with one-click navigation links to all graphics.

Display Layout and Faceplate Handling

Displays need a consistent “look and

feel.” Different DCSs have unique

embedded structures and paradigms

around the location and type of

navigation abilities, faceplates,

“change zones,” programmable keys,

and similar items. These features

should be implemented in such a way

as to comply with the principles of

High Performance displays.

It is important to use these built-in

abilities to their maximum potential.

It is inadvisable to attempt to make a

“Brand XYZ” DCS look like a “Brand

ABC.” The results will usually be far

from optimum.

Layout for a typical screen is shown in Figure 30. Screen layout usually includes these

elements:

● A top menu and status area shows a variety of information, such as screen and

alarm controls. This element is provided by the DCS manufacturer, is often

mandatory, fixed in size, and usually configurable in several ways.

● A bottom “status line” area, usually optional, depicts information about a selected

object, a command, or similar condition.

● A process depiction area is where the graphic is created.

● A reserved area for faceplates is provided. (This reserved area is a High

Performance practice.)

Typical reserved control system menu bar and status area

Reserved faceplate area, desirablenarrow 1/16th of screen faceplate shown

Typical reserved “status line” area

RectangularProcess Depiction Area

Area for navigation buttons or other useful fixed information

Wider 16x9 screens should be used to enlarge the Process Depiction Area

Figure 30: Typical Screen Layout


When screen objects are selected, additional information about them should be shown. This

is typically in the form of a faceplate popup. If the operator can interact with or manipulate

the object, the interface for that interaction is contained in the faceplate. A reserved area in

which the faceplate appears is important. It is undesirable for a faceplate to appear randomly

on the screen, obscuring the primary graphic, and then requiring it being manually dismissed

or moved. Reserved areas should be a rectangular area on the upper or lower right side of the

screen, or a narrow strip across the bottom or right-hand side.

The size of the reserved faceplate area is determined by the brand of DCS. Ideally, faceplates are

tall and narrow. This provides for placing them adjacent to the right-hand edge of the graphic,

leaving a large, contiguous, mostly rectangular area for the process depiction. But, some DCSs

have faceplates that are large, square, clunky, and poorly organized, making a reserved area for

them difficult to accomplish. If you own such a system, encourage the manufacturer to move

into the 21st century and modify their standard faceplates.

Only one item on a screen should be selectable at a time. Any new selection on the screen

should replace any prior faceplate from a prior selection, without any manual “closing” of

the prior faceplate needed. On a few screens, it might be desirable to enable more than one

faceplate at a time.

Faceplates are usually supplied as standard elements by the DCS manufacturer. It may or may

not be possible to alter them, and they may not follow some of the principles you desire for

your HMI, such as proper and consistent use of color. However, rebuilding or replicating dozens

of standard faceplates from scratch to correct minor consistency issues may not be worth the

effort, since future vendor software upgrades may override that work.

The faceplate should show the point name and description, since point names should not

normally be shown on a graphic. Exposing even more configuration information (i.e., Level 4

“point detail” or configuration data) about the point should be possible from the faceplate

element. Faceplate interaction should not be modal (i.e., preventing other graphic action until

the faceplate is closed).

We have seen a presentation advocating that faceplate functionality (altering setpoints, outputs,

modes, states, etc.) be incorporated into the graphics themselves, and the use of the standard

faceplate interaction eliminated. Now, as you can imagine, we are always open to evaluating

new ideas, but not every new idea is a good one! The claim is made that “it is speedier and the

operator might save fractions of a second per interaction that way, which will add up to maybe

several hours saved per year.” This is a bad idea, because huge amounts of additional custom

coding and its upkeep are needed and significant layout and consistency problems must be

addressed. Stick with faceplates.


Depending on DCS HMI capabilities, other methods for point information manipulation are

possible, such as right-click menu access.

Avoiding “Blob” GraphicsSome places have carried the gray-scale principle

too far and created extremely low-contrast “blob”

graphics shown in Figure 31. These are gray-on-gray,

typically without even thin black boundary lines

defining the various elements. These are a bad idea;

we have seen many operators squinting at these to

figure out what is happening. Graphics should be

clear and unambiguous, and blob graphics are not

recommended. The key is to provide easy visibility

of elements, but to reserve emphasis for abnormal

situations.

Display HierarchyDisplays should be designed in a hierarchy that provides progressive exposure of detail. Displays

designed from a stack of P&ID schematic designs will not have this; they will be “flat” like a

computer hard disk with one folder for all the files. This does not provide for optimum situation

awareness and control. A four-level hierarchy is desired.

65.1

68.2

70.5

72.6

80 %

22 %

64.2 C-42

C-44

107.56

Figure 31: “Blob Graphic” Elements with Insufficient Contrast

Level 2

Process UnitControl Display

Level 2

Process UnitControl Display

Level 2

AbnormalSituation Tasks

Level 3

Process UnitDetail Display

Level 3


Level 3


Level 4

Process UnitSupport Display

Level 4


Level 4


For Each Overview Display, Multiple Level 2 Process Unit Detail Displays

For Each Level 2 Display, Multiple Level 3 Process Unit Detail Displays

For Each Level 3 Display, Multiple Level 4 Process Unit Support Displays

Smaller equipment groups, Controllers,

Alarms, Values, Trends, ESD Displays, Equipment

Status

Interlocks, Details, Diagnostics, “First-Outs,”

Procedures, Documentation, Help

Level 1

Process AreaOverview Display

Controllers, Values, Alarms, Trends, Status

Note: Possibly More than one Overview Display available, designed for significantly different operating states

Figure 32: High Performance HMI Display Hierarchy


Level 1 – Operation Overview

This is a single graphic showing the operator’s entire span of control, the big picture. It is an

overall indicator as to how the operation is running. It provides clear indication of the current

performance of the operation by tracking the Key Performance Indicators as in Figure 33.

Level 1 Overview graphics are usually not designed for making control interactions (i.e., no

faceplate zone).

The Figure 33 example is from a large power plant. We often hear “But it doesn’t look like

a power plant!” Correct! Does your automobile instrument panel look like a diagram of your

engine surrounded by numbers? The display is designed so that it is easy to detect if the plant

is running well or poorly, and that important abnormal conditions and alarms stand out clearly.

The Level 1 graphic is ideal for display on a large, perhaps off-console monitor. Many have

purchased such large screens with little idea of how to make the best use of them.

AD-ONPULVStatus

A2 CWP

B2 CWPE-ONC-ONF-OFF

H-ONA-OFFG-ON

Alarms

E

B

F

C

G

D

H

PUMPS ANDFANS

Pump Status

ON

ON

A2 HWP

B2 HWPON

OFF

C2 HWP

SUBFPON

ON

A2BFPT

B2BFPTON

ON

A2 ECW

B2 ECWON

ON

Fan StatusA2 FDON

ON

B2 FD

B2 IDON

ON

A2 PA

B2 PAON

ONA2 ID

7.1

A/F Ratio

9.4

BBDpH

9.4

EconpH

Boiler

775

Econ GasOut °F

300 -0.5

Aux Stmpsig

25 25 7.0Auto

351

25 6.0 21 0.45 0.9 200 90

F. in.H2OA2IDStall

A2FDStall

Fans B2IDStall

B2FDStall

Econ% O2

Sec Airin. H2O % Opac

NOX#/MMBTU

SO2#/MMBTU

CEMS COppm

Inst Airpsig

702.1 640.1 -5.2

MVARTurbine-GeneratorGross MW

60.00 0.2 0.2

LPT-Ain.hg

49.1 3.13.1 20.1 -0.5 9.0

H2psig

H2°F

Turb Oil°F

StatorGPM

Condenser-Feed WtrA2 BPFT B2BPFT

Drum LvlIn. H2O

HW Lvlin.H2O

DA Lvlin.H2O

DA WideFT H2O

Cond Hdrpsig

104 115Auto Auto

Net MW HZLPT-Bin.hg

400Auto

0.0Auto

25

B-ON

05-31-1413:22:07

Unit 2Overview

1

Total Alarms

0

5

80

-450

-15 1 HR

50005000

15

SteamKLBH4100

Fd WtrKLBH4580

DrumLvl in.

-0.5

-30 -15

0

-450

-5 1 HR

75001250

5

AirKLBH5820Coal

KLBH980

FurnPres-0.5

-30 -15

600

-45600

0 1 HR

120012003000

Steam°F

990Reheat

°F1005

Steampsig2400

-30 -153

2

2

2

Figure 33: Example Level 1 Display


Level 2 – Unit Control

Every operation consists of smaller, sub-sectional unit operations. Examples include a single

reactor, a pipeline segment, a distillation train, or a compressor station. A Level 2 graphic exists

for each separate major unit operation. It is designed to contain all the information and controls

required to perform almost all operator tasks associated with that section, from a single graphic

as shown in Figure 34.

Notice how the analog indicators and controllers are lined up for easy scanning, rather than

being scattered all around a P&ID depiction. Ease of abnormal situation detection is an important

HPHMI design consideration.

When properly designed, most operator actions will occur at Level 2, and the Level 3 graphics

will be used only for more detailed troubleshooting.

VENT SYS

ThioniteProduct: Mid-Run

PRODUCT

SHUTDOWN M5

IN OUT

Calc Diff:

-10%

+10%

238.1

State:

19.7 19.3

2.1 %

FREEZEM5

80.5

%A

15.5

%B

4.0

%CFeed Composition

77.5Auto

Feed MPH

11.9Auto

ADTV-1 MPH

4.0Auto

ADTV-2 MPH Reserved

Faceplate Zone

When any item on the screen is selected, the faceplate for that item appears in this reserved area.

All control manipulation is accomplished through the standardized faceplates.

Reactor M5

80.5

Coolant:GPM °C

15.5

PurgeMCFH

4.0

Cat.Act%

Conv.Eff. %

80.5 15.5

75.0

75.9Auto

54.3%

Lvl%

92.0

Prod MPH

45.0Auto

Temp °C

112.2Auto

Pres psig

To CoilsAgitator

ON

M5 Circ

ISOLATEM5

ON-OKRTAM:Run Plan:

Actual:

Main Menu

L2 M5 Startup

L2 M5 Scram

M5 Vent Sys

Daystrom Pumps

M5 Agitator

L2 Feed System

L2 Prod Recovery

M5 Interlocks

M5 Cooling Sys

---- Level 3 ----

L2 Compression

L2 RX Summary

I I-5A I-5B I-5C

I-5D I-5E I-5F

Feed ADTV-1 ADTV-2

Temp Pres Level

Interlock Actions:Stop Feed Stop ADTV-1Stop ADTV-2

Max CoolMax Vent

OFFOFFOFF

OFFOFF

0%

Out:

%DIFF

Open Open Open Open

Backup Lvl %75.8

40.0 -60 -30-90 2 Hrs

48.0

Temp °C

OP

Open

Open 5.0 %

Open

2.0 -60 -30-90 2 Hrs

6.0

ADTV2

MPH

OP

10.0 -60 -30-90 2 Hrs

14.0

ADTV1

MPH

OP

72.0 -60 -30-90 2 Hrs

80.0

Feed MPH

OP

I

I

I

I

I

27%

17%

48%

53%

48 %35 %

32.0 -60 -30-90 2 Hrs

40.0

Analysis: Inhibitor Concentration %

4.0 -60 -30-90 2 Hrs

6.0

Analysis: Purity %

Reactor M5In:Material Balance

Hours:

74.3 %

Pump A

Running

OK

Pump B

Fault

Stopped

Pumps Needed: 1

Max Circ OFF

2

4

3

Figure 34: Example Level 2 Display of a Reactor


Level 3 – Unit Detail

Level 3 graphics provide all of the detail about a single piece of equipment. These are used for

detailed diagnosis of problems. They show all of the instruments, interlock status, and other

details. A schematic or P&ID type of depiction is often desirable for a Level 3 display.

The Figure 35 example shows what could be created “from scratch” as a Level 3. Besides the

P&ID depiction, other HPHMI elements are included. In existing systems, most graphics are

actually Level 3. See the “HPHMI Implementation on a Budget” section in the Part 2 document

for guidance about this.

Level 4 –Support and Diagnostic DisplaysLevel 4 displays provide the most detail of subsystems, individual sensors, or components.

They show the most detailed possible diagnostic or miscellaneous information. A “Point Detail”

display is a typical example. The dividing line between Level 3 and Level 4 displays can be

somewhat gray.

PSOAUTO

76.8 MSCFH76.088.5 %

Flow Demand

RUNNING

PSOCAS

90.090.0 %

WC Speed

65.0 °C

West Comp Discharge Temp °C

40.0

50.0

-60 -30-90 2 Hours

1st

Stage

2nd

Stage

CW

32.0 °C

20.0 °C

28.0 °C

WESTCOMP

OH

44.0 °C

90.8 %

48.0 psi

90.0 psi

EAST COMP

20.1 psi

111.0 °C

West Compressor Interlock Initiators

Comp in Overspeed

Winding Temp is High

Vibration is High

1 Stg Pres is High

2 Stg Pres is High

Suction Pres is Low

Oil Pres is Low

NO

NO

NO

West Comp Flow MSCFH

45.0

55.0

-60 -30-90 2 Hours

48.4 MSCFH

West Comp Speed %

85.0

95.0

-60 -30-90 2 Hours

RECOVERY

West Compressor

95.1 Oil psi

---- Level 3 ----

I W-1A W-1B W-1CI IMech Flow Pres

MANUAL ACTIONS

NO

NO

NO

Total Flow is Low

West Compressor Interlock Actions

W. Comp Shutdown

Inlet Block Valve

Outlet Block Valve

Flow Cascade to Manual

Maximum Flow Bypass

Maximum Cooling

E. Comp Override to 100%

NO

OPEN

OPEN

NO

NOCLOSED

NORM

OFFWinding PurgeNO

NO

Inter-cooler

---- Level 4 ----

OPEN

OPEN

Main Menu

L2 Compression

L2 Recovery

East Comp

Seq. Overlay

Startup Overlay

Logic Diagrams

Procedures

West Interlocks

West Cooling

Reserved Faceplate Zone

When any item on the screen is selected, the faceplate for that item appears in this reserved area.

All control manipulation is accomplished through the standardized faceplates.

IDLEWESTCOMP

PURGEWESTCOMP

ISOLATEWESTCOMP

SHUTDOWN WESTCOMP

Speed%

90.8Cas

76.8Auto

48.0 90.0 65.0 32.0

Tot FlowMSCFH

1 Stgpsi

2 Stgpsi

CLR In°C

CLR Out°C

Winding°C

111

FLOW-SPEED CASCADEIN EFFECT

EAST COMP

Figure 35: Example Level 3 Display


Conclusion of the Part 1 DocumentThe principles of High Performance HMI are specifically developed to deal with the needs of

today’s operators regarding the complex systems they manage. A High Performance HMI is

designed to be the best tool for operator interaction with the process control system. It is

designed to maximize operator situation awareness and abnormal situation detection and

response.

In the separate Part 2 document, we provide case studies supporting that a High Performance

HMI accomplishes these goals. In addition, there is discussion of a major HMI-related advance

in the power industry, a review of HMI Standards, and an example Table of Contents of HMI

Philosophy and Style Guide documents.


About the AuthorsBill R. Hollifield, PAS Principal Alarm Management and HMI Consultant

Bill is the Principal Consultant responsible for the PAS work processes and

intellectual property in the areas of both Alarm Management and High

Performance HMI. He is a member of the American Petroleum Institute’s API

RP-1167 Alarm Management Recommended Practice committee, the ISA SP-

18 Alarm Management committee, the ISA SP101 HMI committee, and the

Engineering Equipment and Materials Users Association (EEMUA) Industry

Review Group.

Bill has multi-company, international experience in all aspects of Alarm Management and HMI

development. He has 28 years of experience in the petrochemical industry in engineering and

operations, and an additional 12 years in alarm management and HMI software and services for

the petrochemical, power generation, pipeline, pharmaceutical, and mining industries.

Bill is co-author of The Alarm Management Handbook, The High Performance HMI Handbook, and

The Electric Power Research Institute (EPRI) Guideline on Alarm Management.

Bill has authored several papers on Alarm Management and HMI, and is a regular presenter on

such topics in such venues as API, ISA, and Electric Power symposiums. He has a BSME from

Louisiana Tech University and an MBA from the University of Houston. In 2014, Bill was made an

ISA Fellow.

Hector R. Perez, PAS High Performance HMI Product Manager

Hector oversees the High Performance HMI business line at PAS. He is a

chief designer of High Performance graphics intended to facilitate situation

awareness in a variety of industries. At PAS, Hector oversees PAS software

directions to improve product design and capabilities.

Prior to working with PAS, Hector was a senior engineer at Schlumberger. His

strength in design contributed to his success in creating new and improved

HMIs for reservoir evaluation services and interfaces for business Key

Performance Indicator tracking.

In addition to his expertise in High Performance HMI, Hector has widespread experience in all

aspects of Alarm Management. He has facilitated numerous Alarm Management workshops,

conducted alarm rationalization projects, and developed Alarm Philosophy documents for a wide

range of clients in the petrochemical, power generation, pipeline, and mining industries.

Hector has authored technical articles on High Performance HMI. In 2009, he and Bill collaborated

with the Electrical Power Research Institute (EPRI) on a comparative research study evaluating

High Performance graphics and operator effectiveness. Hector holds a Bachelor of Science in

Chemical Engineering from Rice University.


ReferencesAPI-RP-1165: Recommended Practice for Pipeline SCADA Displays, American Petroleum Institute

(2006)

Crawford, W., Hollifield, B., Perez, H., Electric Power Research Institute Operator HMI Case Study:

The Evaluation of Existing “Traditional” Operator Graphics vs. High Performance Graphics in a

Coal Fired Power Plant Simulator, Product ID 1017637 (2009)

Hollifield, B. Oliver, D., Nimmo, I., and Habibi, E., The High Performance HMI Handbook. PAS (2008)

Hollifield, B. and Habibi, E. 2006. The Alarm Management Handbook, 2nd edition. PAS (2010)

ANSI/ISA-101.01-2015: Human Machine Interfaces for Process Automation Systems, International

Society for Automation, August 2015


About PAS

PAS Global, LLC is a leading provider of software solutions for process safety, cybersecurity, and

asset reliability to the energy, process, and power industries worldwide. PAS solutions include

industrial control system cybersecurity, automation asset management, alarm management, high

performance HMI, boundary management, and control loop performance optimization. PAS

solutions are installed in over 1,000 facilities worldwide with more than 40,000 users.

For more information, visit www.pas.com.

Connect with PAS on Twitter @PASGlobal or LinkedIn.

© PAS Global, LLC 2017. Ideas, solutions, suggestions, hints and procedures from this document are the intellectual property of PAS Global, LLC and thus protected by copyright. They may not be reproduced, transmitted to third parties or used in any form for commercial purposes without the express permission of PAS Global, LLC.

Documents

Maximize Operator Effectiveness papers... · the ISA-101 HMI Standard released in August 2015. HPHMI Work Processes and Implementation Guidance: The work process for HMI improvement