Plant Modeling Based on SysML Domain Specific Language

Abstract

Successful implementation of Model-based Systems Engineering(MBSE) obviously needs a model supporting efficient communication among engineers of various domains. The system modeling language standard, SysML is designed to create MBSE supporting models. However, SysML itself is not practical enough to be used for real-world engineering projects. As SysML is designed for generic systems and requires specialized
knowledge, a model written in SysML has a limited capability to support communication between a systems engineer and a subsystem engineer.
Our research’s main goal is to develop a SysML based plant model integrating most outputs from plant design phases. As mentioned, a standard SysML based plant model is not specific enough to be understood by plant engineers. To make the SysML model more practical, a customized SysML for the plant engineering domain is required. Unfortunately, current researches on SysML Domain Specific Language(DSL) for the plant engineering industry are still on the early stage.
So, as a pilot, we have developed our own SysML-based Piping & Instrumentation Diagram (P&ID) creation environment and P&ID itself for a specific plant system, via widely known SysML modeling tool called MagicDraw. P&ID is one of the most important output during the plant design phase, which contains all information for the plant construction phase. So a SysML based P&ID has a great potential to bridge gaps between plant engineers.

Full text

Plant Modeling Based on SysML Domain Specific
Language
Taekyong Lee, Jae-Min Cha, Joon-Young Kim, Junguk Shin, Jinil Kim, Choongsub Yeom
Plant Systems Engineering Team
Institute for Advanced Engineering(IAE)
Yong-in, Korea
TKLee@iae.re.kr
Abstract—Successful implementation of Model-based Systems
Engineering(MBSE) obviously needs a model supporting efficient
communication among engineers of various domains. The system
modeling language standard, SysML is designed to create MBSE
supporting models. However, SysML itself is not practical
enough to be used for real-world engineering projects. As SysML
is designed for generic systems and requires specialized
knowledge, a model written in SysML has a limited capability to
support communication between a systems engineer and a sub-
system engineer.
Our research’s main goal is to develop a SysML based plant
model integrating most outputs from plant design phases. As
mentioned, a standard SysML based plant model is not specific
enough to be understood by plant engineers. To make the SysML
model more practical, a customized SysML for the plant
engineering domain is required. Unfortunately, current
researches on SysML Domain Specific Language(DSL) for the
plant engineering industry are still on the early stage.
So, as a pilot, we have developed our own SysML-based
Piping & Instrumentation Diagram (P&ID) creation
environment and P&ID itself for a specific plant system, via
widely known SysML modeling tool called MagicDraw. P&ID is
one of the most important output during the plant design phase,
which contains all information for the plant construction phase.
So a SysML based P&ID has a great potential to bridge gaps
between plant engineers.
Keywords—MBSE; SysML; SysML Domain Specific
Language; P&ID;
I.
I
NTRODUCTION
With the increasing complexity of today’s systems,
traditional document-based engineering has reached its limit.
Systems are becoming too complex to be developed and
managed through documents. Model-Based Systems
Engineering(MBSE) is considered as a long-term alternative to
document based engineering in order to keep correctness,
consistency and traceability across all engineering items
created through a system life cycle.
In the context of MBSE, a model representing a system and
its environment is a basis of communication among
stakeholders from different domains [1]. Successful
implementation of MBSE obviously requires models
supporting efficient information sharing. Systems Modeling
Language(SysML) is one of the most actively used language
designed to create such a model.
However, SysML itself is not practical enough to be
applied to a specific field of industry as it is designed to model
general systems. Well-written SysML based model does
express various aspects of systems deeply but engineers need
professional knowledge and skills to understand the
information contained in the model. So, as described in Fig. 1,
with a standard SysML based model, information sharing
among engineers will be limited as each engineering team
needs system engineers who can understand the model. To
apply a SysML based model to real-world industries, the model
needs to be created by a customized SysML for a specific
domain so that corresponding domain experts can easily
communicate through the model.
To explore the applicability of customized SysML models
for plant engineering industry, we have developed a SysML
based Piping & Instrumentation Diagram(P&ID) prototype of
the waste-to-solid fuel plant designed by our research institute.
P&ID is a key product of any plant design phase, most plant
engineering activities are related to P&ID. So, SysML based
P&ID can be regarded as the most important step to develop a
whole plant model.
Fig. 1. As-is vs To-be
Fig. 2. Hierarchy of modeling languages

II. S
YS
ML
D
OMAIN
S
PECIFIC
L
ANGUAGE
A. Definition
The idea of Domain specific languages(DSL) may sound
new, but this is a venerable tradition in the field of
programming [2]. Both HTML and Matlab are powerful script
languages for web presentation and engineering applications
but they are limited for developing generic software [2]. This is
the nature of DSL. From the viewpoint of Systems
Engineering, DSL can be defined as modeling languages
modified or extended for user’s domains. SysML itself is also a
DSL extended from Unified Modeling Language(UML)
defined by Objective Management Group(OMG). Fig. 2 shows
the hierarchy of modeling languages for better understanding.
SysML is extended from UML, and SysML can also be
customized for various domains.
B. SysML Domain Specific Language Development
SysML elements can be extended to domain specific
elements by using a concept of profile. All customization data
– relationships between original elements and DSL elements,
changed/added/deleted properties – are stored in a profile and it
can be reused for any project. MagicDraw [5], which is one of
the most widely used UML/SysML modeling tool provides
DSL engine which helps to define profiles. Fig. 3 shows how a
profile is composed and how DSL element is realized by a
profile.
C. Related Works
Studies on UML/SysML based DSL for various domains
from aerospace industry [2] to Computer Aided Design(CAD)
model [3] have actively undertaken. These studies put focus on
building domain specific schematic vocabulary [2] based on
the standard UML/SysML semantics. Our study on SysML
based P&ID was also inspired from these works.
III. P
LANT
M
ODELING
:
P&ID
P
ROTOTYPE
D
EVELOPMENT
A. Scope
A plant is usually consisted of mechanical systems
(equipment, valves, pipes, etc.) control systems, electrical line
systems and others. And P&ID usually provides information of
how mechanical and control system are integrated together. In
our case, we limited the scope of the work to mechanical
systems of the chosen waste-to-solid fuel plant as mechanical
systems are most important parts of a plant that needed to be
defined and designed earlier than others.
B. Development Process
1) Define customized element classes
• Mechanical systems of a plant are generally consisted
of equipment, valves and pipes. Through the analysis of
design data of the waste-to-solid fuel plant, we defined
element classes needed to draw P&ID of the plant. Fig.
4 shows elements classes. Equipment needed for the
plant was defined with customized properties and data
types. Various types of valves were also defined with
their own properties. And Pipes, which were extended
from “Connector Class” of the standard SysML were
defined. Image files of P&ID symbols were also
assigned to corresponding element classes.
2) Organize the element classes as a single profile
• Defined element classes were packaged and arranged as
a single profile so that it can be reused for any related
project. Fig. 5 shows the structure of the created profile.
3) Define SysML based P&ID drawing environment
• Using the diagram customization wizard provided from
MagicDraw, defined element classes were arranged to
the P&ID palette (Fig. 6). The P&ID drawing
environment was created by modifying a SysML
Internal Block Diagram(IBD) definition, so relationship
rules not customized follow the rules of IBD.
Fig. 3. Concept of SysML Domian Specific Language Realized on MagicDraw [6]

IV. P&ID
P
ROTOTYPE
E
XAMPLES
As all needed element classes were defined and arranged on
the diagram palette, a user can draw a P&ID of the waste-to-
solid fuel plant based on SysML even if he/she is not a SysML
expert. A user just needs to drag and drop elements from the
diagram pallet to the plane and connect them with the right
piping connectors Fig. 7 shows the overview of the P&ID
prototype. Though only major mechanical systems have been
expressed, it is still quite similar with the original P&ID.
Fig. 8 shows what information that each element contains.
Each symbol shown on the figure is a modifiable element
which contains information needed for plant engineers.
Elements’ properties from the standard SysML are hidden and
only customized properties – defined in the plant engineering
DSL profile - needed for plant engineers are shown in each
element’s specification.
Fig. 9 shows another part of P&ID where the main
equipment is connected to external systems. Standard SysML
elements and relationships such as block and trace can also be
added to P&ID. And defined properties of pipe lines, valves
and equipment can be displayed on P&ID to give a better
understanding.
Equations
The equations are an exception to the prescribed
specifications of this template. You will need to determine
whether or not your equation should be typed using either the
Times New Roman or the Symbol font (please no other font).
Fig. 5. Defined Plant Equipment, Valve, Pipe (clockwise) Classes
Fig. 4. Plant Engineering DSL profile
Fig. 6. SysML based P&ID Drawing Environment

Fig. 7. SysML Based P&ID Prototype(left) and Origninal P&ID(right)
Fig. 8. P&ID Element Properties
Fig. 9. Displayed P&ID Element Properties

V. C
ONCLUSION AND
F
UTURE
W
ORK
An example of a plant engineering P&ID prototype has
been developed to explore the applicability of customized
SysML models to the plant engineering industry. The P&ID
prototype developed using MagicDraw was satisfactory as a
pilot. However, there are several major issues found during the
research and resolving these issues will be our future works to
make the P&ID prototype more practical for plant engineers.
Future works are followings:
• Resolving Visual Representation Issues: Several issues
were found while representing P&ID symbols. In case
of MagicDraw, all SysML element shapes are not just
images, these shapes are created by JAVA so all
conditions (initial size, ratio, boundary shape, etc.) are
already defined. But the P&ID prototype’s symbols are
just vector images so it needs to re-write P&ID symbols
with JAVA Open API provided from MagicDraw.
• Model to Model Transformation: Model to Model
transformation rules should be developed so that a
standard SysML based model for system engineers and
a domain specific SysML based model for sub-system
engineers should be easily convertible. If a user need to
manually draw a SysML based P&ID every time, it is a
huge loss of man hours.
• Tool Free Application: In the long run, DSL profiles
and diagram creation environment need to function in
any SysML authoring tool.
A
CKNOWLEDGMENT
This work was supported by the Technology Innovation
Program (10063187, Engineering Technique for Power
Generation System Design using Industry Waste Heat,
10072058, Model Based Configuration Management System
for Empowering Maintenance Engineering Capability of
Small/Medium Size Plant) funded By the Ministry of Trade,
Industry & Energy(MOTIE, Korea).
R
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.
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