FIELD OF THE INVENTION
The present invention relates to an improved automation system for control and
online diagnostics of drives in Furnace Area of merchant mill in a steel plant. More
particularly, the present invention is directed to a centralized Programmable Logic
Controller (PLC) and remote I/O (Input/ Output) based monitoring and control
system for all six control drives/ mechanisms and parameters of furnace area,
charging area, Motor Oil Cellar, Mill Oil Cellar, Ashlow system and furnace exit side
all Solenoids mechanism. The system is adapted to be implemented in the Merchant
Mill of the Steel Plants with desired advantage.
BACKGROUND OF THE INVENTION
Merchant mill in applicants' steel plant is a continuous mill comprising of 13 stands
for reduction of billets to different sizes and shapes. Any breakdown in any of the
control mechanism leads to mill stoppage/generation of cobbles. Reliability of six
Constant Voltage Direct Current (CVDC) drives of furnace and charging area were
required to be improved as any breakdown results in complete stoppage of
production.
The Mill is designed for rolling and finishing of 25m, 20mm and 16m TMT bars. Any
breakdown in any of the control mechanism leads to mill stoppage/generation of
cobbles. The operations and controls are distributed from several pulpits and motor
room. In addition, mill is supported by several facilities that are critical for operation
of mill as well as maintaining quality.
It was proposed to improve the Mean Time to Repair (MTTR) & Mean Time between
Failures (MTBF) of the equipment of Furnace area CVDC; because the existing relay
logic based control system at charging and furnace there was a problem of frequent
breakdown. The breakdown's root cause analysis as well as liquidation was taking
time because of old and not user friendly control scheme with absence of any alarm/
fault annunciation mechanism.
In the existing system, the drive control panels were relay logic based control circuits
and the interfacing of the input signals from the control pulpits to control panels and

finally the output to the main control mechanism i.e. motors was through multicore
control cable through the hazardous routes and also there was no online/ historical
data storage facility for post analysis of the faults. The existing system thus suffered
from a number of disadvantages and limitations which included:
1. Frequent Hardwired/ old control circuit failure;
2. Time consuming root cause analysis and liquidation;
3. Cumbersome modification in control circuit;
4. Failure of Multi-core control cables through hazardous routes;
There has been therefore a persistent need to address the above limitations by
developing an improved monitoring and control system with less breakdown and
easy troubleshooting/maintenance. Thus by way of the present invention, a
centralized Programmable Logic Controller (PLC) and remote I/O based monitoring
and control system has been conceived, designed and implemented for all major
equipment, mechanisms and parameters of furnace area, charging area, Motor Oil
Cellar, Mill Oil Cellar, Ashlow system and furnace exit side all Solenoids mechanism.
OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to provide for an improved
automation system for control and online diagnostics of drives in Furnace Area
involving a centralized Programmable Logic Controller (PLC) and remote I/O based
monitoring and control system for control and online diagnostics of all drives.
A further aspect of the present invention is directed to providing an improved
automation system for control and online diagnostics of drives in Furnace Area which
would avoid Frequent Hardwired/control circuit failure.
A still further aspect of the present invention is directed to providing an improved
automation system for control and online diagnostics of drives in Furnace Area
wherein faster fault detection/root cause analysis and liquidation is possible.
A still further a object of the present invention to providing an improved automation
system for control and online diagnostics of drives in Furnace Area wherein use of

Multi-core control cables is eliminated and thereby its failure due to hazardous work
site is avoided.
A still further an object of the present invention to providing an improved automation
system for control and online diagnostics of drives in Furnace Area wherein online
diagnostics tools and instantaneous equipment status is made available by providing
display boards and HMI stations.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to an automation system for
control and online diagnostics of drives in Furnace Area comprising
centralized monitoring and control involving PLC and Remote I/O,
interconnected over Ethernet (TCP/IP) network backbone, adapted for
controlling anyone or more of drives/mechanisms and parameters of furnace
area including charging area, motor oil cellar, mill oil cellar, ashlow system
and furnace exit side operating mechanism;
Display boards to depict status of those signals and means adapted to carry
out coordinated operation of the mill; and
HMI stations for display of large number of information relating to desired
automation with or without historical recording for development and
maintenance and providing interface with any existing LAN backbone.
A further aspect of the present invention is directed to said automation system
comprising distributed PLC, Remote I/O, control/ operator desk, equipment status/
annunciation display boards, programming terminals, and HMI Stations for
monitoring and control of various mechanism of furnace area, charging area, Motor
Oil Cellar, Mill Oil Cellar and furnace exit side all Solenoids mechanism which are
preferably adapted for controlling Constant Voltage Direct Current (CVDC) drives
comprising Billet Separating Skid, Ram Charger, Cross Pusher, Charging Table, Push
Out Roll and Pull Out Rolls in charging and furnace area, said PLC based monitoring
and control enabling ready and fast implementation based on PLC logic control.

A still further aspect of the present invention is directed to an automation system
wherein said system is built around PLC, remote I/O nodes and HMI stations with
interconnection among all the nodes on TCP/IP through CAT6, all networking
accessories are of industrial grade to make the operation of the network reliable each
node having adequate number of Input and Output modules, which are Digital
and/or analog to interface all the required signals from the field as required for the
application.
A still further aspect of the present invention is directed to an automation system
wherein said programming terminals are for the purpose of programming, trouble-
shooting and monitoring of PLC based networked system and HMI station is for
online status monitoring of the equipments/ parameters.
A still further aspect of the present invention is directed to an automation system
wherein remote 10 based new Control/ Operator desks are placed in CP -1, 2 & 3 to
control/ operate the all six drives of charging and furnace area along with pump and
solenoids of mill area.
Yet another aspect of the present invention is directed to an automation system
wherein said HMI stations along with the display boards at strategic locations are
provided for instantaneous display of status for all equipment through display boards
and HMI stations at strategic locations to reduce the time for fault findings and
acknowledgement.
A further aspect of the present invention is directed to an automation system
wherein input signals for all the field control devices have been taken to the system
with proper isolation and depending upon the location of the field signals, relay
boards have been provided at various places so that outputs are interfaced through
appropriate relays and for interfacing analog signals, appropriate signal isolators are
used.
A still further aspect of the present invention is directed to an automation system
wherein LED - lighted Display Boards based panels installed in Motor Room, Furnace
CVDC room, Electrical Shift Office and motor Oil Cellar for instantaneous overview of

status of equipment and other information wherein LEDs are being driven by PLC
output of maximum 0.5 A per channel and through interposing relays.
A still further aspect of the present invention is directed to an automation system,
wherein there are three level of redundancy in signal communication from desk to
control system involving two network cables laid through two different routes to take
care of any node based network failure and further involving a third level
redundancy operative connection to said PLC.
A still further aspect of the present invention is directed to an automation system
wherein PLC and HMI are provided with software for controlling drives, online data
storage and display of faults through annunciation display boards.
The various other objects and advantages are described in greater details with
reference to the following non limiting illustrative drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1: is the schematic view of Layout of Merchant Mill showing location of
different facilities.
Figure 2: shows the Remote I/O based control desks used in the automation system
for control and online diagnostics of drives in Furnace Area according to the present
invention.
Figure 3: shows the PLC & Networking Scheme for automation system for control
and online diagnostics of drives in Furnace Area.
Figure 4: show the glimpses of Installed Panels.
Figure 5: show the Display Boards at operator's desk.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING FIGURES
The present invention is directed to providing an improved automation system for
control and online diagnostics of drives in Furnace Area involving a centralized

Programmable Logic Controller (PLC) and remote I/O based monitoring and control
system for control and online diagnostics of all drives.
Merchant mill of applicants' steel plant is a continuous mill comprising of 13 stands
for reduction of billets to different sizes and shapes. Any breakdown in any of the
control mechanism leads to mill stoppage / generation of cobbles. The operations
and controls are distributed from several pulpits and motor rooms. In addition, mill is
supported by several facilities that are critical for operation of mill as well as
maintaining quality.
Accompanying Figure 1 show the layout and area of focus (Different Shade) of
project of Merchant Mill with all the mechanisms, Pulpits and Motor Room and their
locations.
The Mill is designed for rolling and finishing of 25m, 20mm and 16m TMT bars. Any
breakdown in any of the control mechanism leads to mill stoppage / generation of
cobbles. The operations and controls are distributed from several pulpits and motor
room. In addition, mill is supported by several facilities that are critical for operation
of mill as well as maintaining quality.
A centralized monitoring and control system has been conceived, designed and
implemented to monitor and control all major equipments, mechanisms of furnace
area, Motor and Mill Oil lubrication system and solenoids operation at the discharge
side of furnace for billet feeding to stand for rolling.
The system involves PLC and Remote I/O based control, interconnected over
Ethernet (TCP/IP) network backbone, four display boards of different designs and
HMI stations. System implementation involves extensive interfacing with existing
field equipment and signals of the shop, requiring a very detailed field engineering
and erection work. With the installation of the new system, information regarding
status of equipment and drives for furnace area is instantaneously available at all
strategic places for co-ordinating operation and control. The system also provides
status of important utilities across the shop such as Hydraulic and lubrication
systems of the Mill and motor area.

The system design provides immense scope for future expansion and enhancement
of operation. The system facilitates reduction of controllable delays as well as
improvement in overall performance of the mill.
The electrical delay of Furnace Area has been reduced by 60% on monthly average
basis.
There are six drives in charging and furnace area. All are Constant Voltage Direct
Current (CVDC) drives namely Billet Separating Skid, Ram Charger, Cross Pusher,
Charging Table, Push Out Roll and Pull Out Rolls. Reliability of six Constant Voltage
Direct Current drives of furnace and mill area were required to be improved as any
breakdown results in complete stoppage of production.
It was proposed to improve the Mean Time to Repair (MTTR) & Mean Time between
Failures (MTBF) of the equipment of Furnace area.
The installed/commissioned system for merchant mill is having monitoring and
control of various mechanism of furnace area, charging area. Motor Oil Cellar, Mill Oil
Cellar and furnace exit side all Solenoids mechanism through two distributed PLC,
seven Remote I/O, four new control/ operator desk, four equipment status/
annunciation display boards, two programming terminal, and two HMI Stations. The
Programming terminal for the purpose of programming, trouble-shooting and
monitoring of PLC based networked system and HMI station is for online status
monitoring of the equipments/ parameters.
Similarly a remote 10 based new Control/ Operator desks as illustrated in
accompanying Figure 2 are placed in CP-1, 2 & 3 to control/ operate the all six
drives of charging and furnace area along with pump and solenoids of mill area.
In order to provide online diagnostics tools and display of equipment status, two HMI
stations along with the four display boards at strategic locations are provided to
reduce the time for fault findings and acknowledgement.
The system has not only enabled establishment of a more reliable control, faster
diagnosis of electrical faults and increase in mill availability due to reduction in

downtime but also provided the automation infrastructure backbone for future up-
gradation in Merchant Mill.
The system has been designed such that future expansion and modification can be
easily implemented. Also the system provides a backbone for integrated automation
and shop-wide MIS by providing open industrial network architecture based on TCP/
IP.
The other objectives of the present invention are to facilitate a reduction in electrical
downtime of furnace area as well as an improved maintenance management system.
In order to achieve the same, the following approach was adopted:
1. Implementation of comprehensive monitoring and control system for
equipment/ CVDC drives of furnace area.
2. Providing instantaneous display of status for all equipment (75 nos. approx.)
through 4 display boards and 2 HMI stations at strategic locations.
3. Installation of an Open Network based PLC & Remote I/O system including
signal interface for existing mill electrics and process parameters as per
application envisaged.
4. Software development for controlling drives, online data storage and display
of faults through annunciation display boards.
The system implementation involved formulation of system design including
finalization of signal I/O list, preparation of specifications for new equipments and
procurement, detailed engineering work, erection including cable laying, PLC & HMI
software development.
The details of the various components of the system and work carried out are
described below:
PLC & Network Scheme

The system configuration with PLC and Networking Scheme is illustrated in
accompanying Figure 3. The figure indicates the connection of each node and
locations of the various display boards and HMI installed. The system is built around
two PLC, seven remote I/O nodes and two HMI stations. The interconnection among
all the nodes is on TCP/IP through CAT6. All required networking accessories
incorporated in the system are of industrial grade to make the operation of the
network reliable. Each node has adequate number of Input and Output modules,
which are Digital and/or analog to interface all the required signals from the field as
required for the application.
Field I/O Interface
The entire system required interface with a large number of inputs and outputs in
existing shop electrics. A very detailed design work was carried out to formulate the
complete I/O listing before commencement of other activities. Input signals for all
the field control devices have been taken to the system with proper isolation.
Depending upon the location of the field signals, relay boards have been provided at
various places. Outputs have been interfaced through appropriate relays. For
interfacing analog signals, appropriate signal isolators have been used. Signal
interfacing work involved extensive conduit, cable laying and termination. Glimpses
of various installed panels are shown in accompanying Figure 4.
Display Boards and HMI for status Monitoring
LED - lighted Display Boards based panels as illustrated in accompanying Figure 5
were specially designed and installed for instantaneous overview of status of
equipment and other information. The LEDs are being driven by PLC output of
maximum 0.5 A per channel and through interposing relays. The Display Boards
panel design, component mounting and wiring has been done with easy accessibility
and maintenance in mind.
Display Boards have been installed in Motor Room, Furnace CVDC room, Electrical
Shift Office and motor Oil Cellar. Design of these Display Boards has been
customized to depict status of those signals and equipment that are required by the
individual operator to carry out coordinated operation of the mill.

Two HMI stations have been installed at PLC room inside Motor room and in CP#4
respectively for display of large number of information w.r.t mechanism along with
historical recording. HMI is also used for development and maintenance and provides
interface with the existing LAN backbone of the plant thus providing a wider access
and interface of data.
Communication with existing signal points of shop
It was required that existing signal be accessed centrally on the new system to
provide centralized monitoring and control. For taking the existing signal various
relay boards are used to interface the field signal with the new PLC system. Relay
boards are fabricated based on the number of signals required to be interfaced from
existing panel using SIEMENS relay. Accordingly 11 Nos. of relay boards having
different numbers of relays were mounted in different location for interfacing of
signals with existing systems.
Erection and Commissioning
Erection & commissioning of the system involved meticulous planning and execution,
utilizing existing shop shutdown, erection of all PLC/RIO and Display Boards panels
without disrupting operations, laying and terminal of a large number of signal cables
and interfacing to field through relays and converters for more than 850 I/Os.
Around 1500m of communication cable has been laid to establish the high speed
communication backbone in the distributed locations.
The remote I/O nodes were configured for communication with the PLC. PLC
application program was developed for the application envisaged and the system
comprising of 2 PLC, 7 RIO nodes, 4 Display Boards and 2 HMI stations was
commissioned accordingly.
It is thus possible by way of the present invention to providing an improved
automation system for control and online diagnostics of drives in Furnace Area of
merchant mill in a steel plant. More particularly, the present invention is directed to
a centralized Programmable Logic Controller (PLC) and remote I/O (Input/ Output)

based monitoring and control system for all six control drives/mechanisms and
parameters of furnace area, charging area, Motor Oil Cellar, Mill Oil Cellar, Ashlow
system and furnace exit side all Solenoids mechanism. Display Boards has been
customized to depict status of those signals and equipment that are required by the
individual operator to carry out coordinated operation of the mill. HMI stations have
been installed for display of large number of information for various mechanism
along with historical recording. HMI is also used for development and maintenance
and provides interface with the existing LAN backbone of the plant thus providing a
wider access and interface of data. The present automation system is thus capable of
ensuring efficient plant operation with less breakdown and easier fault diagnosis and
maintenance increasing plant availability and improved productivity.

We Claim:
1. An automation system for control and online diagnostics of drives in Furnace Area
comprising
centralized monitoring and control involving PLC and Remote I/O,
interconnected over Ethernet (TCP/IP) network backbone, adapted for
controlling anyone or more of drives/mechanisms and parameters of furnace
area including charging area, motor oil cellar, mill oil cellar, ashlow system
and furnace exit side operating mechanism;
display boards to depict status of those signals and means adapted to carry
out coordinated operation of the mill ;and
HMI stations for display of large number of information relating to desired
automation with or without historical recording for development and
maintenance and providing interface with any existing LAN backbone.
2. An automation system as claimed in claim 1, comprising distributed PLC, Remote
I/O, control/ operator desk, equipment status/ annunciation display boards,
programming terminals, and HMI Stations for monitoring and control of various
mechanism of furnace area, charging area, Motor Oil Cellar, Mill Oil Cellar and
furnace exit side all Solenoids mechanism which are preferably adapted for
controlling Constant Voltage Direct Current (CVDC) drives comprising Billet
Separating Skid, Ram Charger, Cross Pusher, Charging Table, Push Out Roll and Pull
Out Rolls in charging and furnace area, said PLC based monitoring and control
enabling ready and fast implementation based on PLC logic control.
3. An automation system as claimed in anyone of claims 1 or 2, wherein said system
is built around PLC, remote I/O nodes and HMI stations with interconnection among
all the nodes on TCP/IP through CAT6, all networking accessories are of industrial
grade to make the operation of the network reliable each node having adequate
number of Input and Output modules, which are Digital and/or analog to interface all
the required signals from the field as required for the application.

4. An automation system as claimed in anyone of claims 1 to 3, wherein said
programming terminals are for the purpose of programming, trouble-shooting and
monitoring of PLC based networked system and HMI station is for online status
monitoring of the equipments/ parameters.
5. An automation system as claimed in anyone of claims 1 to 4, wherein remote 10
based new Control/ Operator desks are placed in CP -1, 2 & 3 to control/ operate the
all six drives of charging and furnace area along with pump and solenoids of mill
area.
6. An automation system as claimed in anyone of claims 1 to 5, wherein said HMI
stations along with the display boards at strategic locations are provided for
instantaneous display of status for all equipment through display boards and HMI
stations at strategic locations to reduce the time for fault findings and
acknowledgement.
7. An automation system as claimed in anyone of claims 1 to 6, wherein input signals
for all the field control devices have been taken to the system with proper isolation
and depending upon the location of the field signals, relay boards have been
provided at various places so that outputs are interfaced through appropriate relays
and for interfacing analog signals, appropriate signal isolators are used.
8. An automation system as claimed in anyone of claims 1 to 7, wherein LED -
lighted Display Boards based panels installed in Motor Room, Furnace CVDC room,
Electrical Shift Office and motor Oil Cellar for instantaneous overview of status of
equipment and other information wherein LEDs are being driven by PLC output of
maximum 0.5 A per channel and through interposing relays.
9. An automation system as claimed in anyone of claims 1 to 8, wherein there are
three level of redundancy in signal communication from desk to control system
involving two network cables laid through two different routes to take care of any
node based network failure and further involving a third level redundancy operative
connection to said PLC.

10. An automation system as claimed in anyone of claims 1 to 9, wherein PLC and
HMI are provided with software for controlling drives, online data storage and display
of faults through annunciation display boards.