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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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