| Multi-Level automation system in Steel
Industry Automation system
is integrated into steel production process in various levels.
Currently there is some dispute on how to divide the levels of the
automation system. In general there are 4-Level model and 3-Level
model. Some people also proposed the Level 5 system, which are
actually the business system such as Customer Relation Management
(CRM), Enterprise Resource Planning (ERP) system. From the view of
the industry control or automation system, Level 4 should be the
top. Typical example of this hierarchy is the Purdue model hierarchy
(see below). Some people also add Level 0: A-C and D-C digital
drives, etc. into the automation hierarchy. However, most people
take it as a basic electric control, not an automation level.
Purdue Model for Control Hierarchy
(5-Level Model)
| Name |
Description |
| Level 0 |
Sensor Level
(Measuring Devices):
Pressure, Temperature, Speed, Accelerometer, Force, Position,
Shape, Thickness, ... |
| Level 1 |
Controller Level
(Feed-back Closed Loop Control):
Speed Regulator, Tension Regulator, Sequence Control, Position
Control, Temperature Control, SCADA |
| Level 2 |
Machine Level
(Set-up Models):
Temperature model (e.g., EAF, LMF), Shape Control, Mill Set-Up
Control, Coil Tracking, Runout Table Cooling Control, ..
|
| Level 3 |
Operation Unit
Level:
Blast Furnace, Electric Arc Furnace, LMF, Caster, Reheating, Hot
Mill, Cold Mill, Anneal Line, Pickle Line, ... |
| Level 4 |
Plant Level - MES,
MRP:
Scheduling, Material Flow, Manufacturing Execution System (MES)...
|
| Level 5 |
Corporate Level -
CRM, TMS, ERP:
Order Process, Enterprise Resource Planning (ERP)... |
This is the most complicated, yet
clearest definition. There is different expertise on different
level, and even different computer in different level. However, this
definition, which considers detailed engineering operation (e.g.,
metallurgical engineering practice), does not fully take into
account computer system architecture and IT practice, and therefore
causes confuse in some situations. For example, when data from
various levels is collected and processed, there will be a problem
on how to handle the data and which level the database or databases)
should be. In this definition, each level holds its own data, and
Level 1 cannot talk to Level 3. The definition is not compatible
with Enterprise System architecture.
4-Level Definition
- Level 0: A-C and D-C
digital drives, etc.
- Level 1: The base
automation. It consists of programmable controllers and
microcomputers that manage the functional logic (e.g. PLCs) of the
system, the single device control and the interface with the
sensors.
- Level 2: The Process
automation. It consists of minicomputers that handle material flow
and production targets, and provide the user with tools for plant
supervision and diagnostics.
- Level 3: The plant wide
production automation. It mainly defines the scheduling of
production in the whole plant, including Meltshop (EAF, LMF),
caster and rolling mill.
- Level 4: Corporate-wide
automation. It consists of business system and quality database,
etc.
3-Level Definition
It is also very common to combine
Level 2 and Level 3 in the 4-Level definition and refer it to "Level
2". This is a very practical way to name the automation system, the
reason for this statement is as follows:
- Level 1 is mainly in the PLC
Level, not much software engineering is required to program PLC
and related control system, e.g. for operator interface with
RSView.
- Corporate-wide business system
(production plan, sales, accounting, etc.), which can be taken as
Level 3, is also quite different from shop floor manufacturing
system.
Based on this consideration, the
3-Level definition consists of followings:
Level 1
PLC level process control, including
PLC and some plant-specific networking, such as Data Highway DH+
from Rockwell. Computer programs can be employed for operator to
control production machinery. However, such programs are primary the
customization based on some PLC interfaces provided by PLC vendor or
automation company. One example of such programs is the customized
steel plant application based on RSView, an PLC interfacing program
by Rockwell Software. PLC setup and some Visual Basic coding skills
are needed to customize such application.
Level 2
Production supervisory system,
plant-wide automation. Automation programs in this level are
developed based on software engineering principle. The system may
extract PLC data (through interactive communication with Level 1),
accept operator user-input and laboratory measurement, as well as
some pre-set manufacture data such as recipes for producing a given
grade, chemical composition for a certain grade, etc. Shop floor
production schedule can be produced, delay, event, part life, etc.
can be tracked. Data from one production process (e.g. EAF) can be
viewed in other process (Caster, for example). All the data can be
saved into a database, such as Oracle or SQL Server. Components,
applications or cub-package relating to process models (mill setup
models, shape control, temperature prediction, etc.) are also
integrated into this level.
Level 3
Level 3 primarily consists of
business related reports, and integration of production database
with the business database, etc. It can integrate multiple Level 2
systems. The data can be cross the plant boundary to be viewed in
the whole corporate. If an automation system collects data into an
enterprise database (Oracle, SQL Server, etc.), the database and the
reports generated from this database belong to the Level 3. Those
manufacture data in the enterprise database can be further sent to
the corporate business database, which is not taken as Level 3 in
general. Scheduling system, Material Flow, Manufacturing Execution
System (MES) can be considered as Level 3.
In this website, if not specified, we
use this 3-Level definition.
Level 2 Functions
In this section we explain a Level 2 package as example. The
Level 2 applications for the EAF, LMF and CAS (Caster) will be
implemented on a Windows system. The EAF, LMF and CAS MMI Computers
will display the Level 2 screens to the operators; theoe computers
will communicate to the Level 2 through TCP/IP sockets. Some data
are shared across applications; for example, the caster Level 2 CAS
can display some summary screens of EAF and LMF.
A list of all applications and corresponding screens are shown in
the following table:
|
No. |
Application |
EAF |
LMF |
CAS |
|
1 |
Production Schedule |
Y |
Y or
N |
Y or
N |
|
2 |
Scrap charge |
Y |
N |
N |
|
3 |
Delay tracking |
Y |
Y |
Y |
|
4 |
Event tracking |
Y |
Y |
Y |
|
5 |
Material additions |
Y |
Y |
N or Y |
|
6 |
Chemistry |
Y |
Y |
Y |
|
7 |
Life Data |
Y |
Y |
Y |
|
8 |
Overview |
Y |
Y |
Y |
|
9 |
Heat Summary |
Y |
Y |
Y |
|
10 |
Cut List |
Y |
Y or
N |
Y |
|
11 |
Meltshop overview |
Y |
(Y) |
(Y) |
|
12 |
Shop Schedule |
Y |
(Y) |
(Y) |
|
13 |
Electrode |
Y |
N |
N |
|
14 |
Heatlineup |
Y |
(Y) |
(Y) |
|
15 |
Personnel |
Y |
Y N |
Y |
|
16 |
Models |
Y |
Y |
Y |
In the table above, "Y" indicates
the screen for the corresponding application (EAF, LMF or CAS) is
needed, and "N" not necessary. The "Y or N" means either needed or
not necessary, and "(Y)" means the screen is needed, but the screen
is the same as that in another application.
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