Claims:WE CLAIM:

1. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant comprises of:
A plurality of PLC Processors for wheel handling mechanisms of two lines of surface finishing;
a plurality of Remote Input Output based units with profinet scanner module configured for communication with CPU and RIO in ring network, Power supply module, Digital input Module and Digital output modules for interfacing the field process and feedback signals to the processor;
a plurality of field sensors like Limit switches, Pressure switches, Solenoids configured for generating a reference signal generation to the controller for process control and command signals are generated as per logic by the PLC to start particular drive associated with the said mechanisms;
a centralized monitoring and control unit including an operator desk, number of Push buttons, number of selector switches, number of LED indications and emergency switch adapted to interface the machine and switch over to different modes of operation; and
a networking architecture wherein the PLC and RIOs are networked in ring topology with profinet protocol and the PLCs are connected on Ethernet protocol.

2. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein PLC-RIO based system, the linked components and associated switchgears are configured for proper wheel handling operations.

3. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the centralized monitoring and control unit further includes a closed loop feedback system involving field sensors like limit switches and pressure switches.

4. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the wheel handling mechanism includes automated wheel loading and unloading to and from the VTB.

5. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the programmable controllers (PLC) includes Central Processing Unit, profinet controllers and standard Power supply modules.

6. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the RIO Panels with RIO modules further comprises profinet scanner modules, power supply modules and standard digital input and output modules.

7. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the Operator Desks comprises number of Push buttons, selector switches, LED indications and emergency switch configured for interfacing the machines.

8. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the profinet based ring network between PLC and RIO ensures redundancy in communication and smooth data transfer.

9. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the data transfer from controller to respective terminals is carried out through the Ethernet instantly.

10. A system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant as claimed in claim 1, wherein the fault diagnosis & its analysis is carried out through online and historical data available in database.

Dated: this 22nd day of August, 2017

(N. K. Gupta)
Patent Agent,
Of NICHE,
For SAIL
To
The Controller of Patents,
The Patent Office, Kolkata.

, Description:A SYSTEM FOR CENTRALIZED MONITORING AND CONTROL FOR WHEEL HANDLING IN FINISHING LINES AT WHEEL AND AXLE PLANT

FIELD OF INVENTION

The present invention relates to a system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant. More particularly, the invention relates to the Design and development of a system for centralized monitoring and control for wheel handling in finishing lines using PLC-RIO based networked control system for wheel handling mechanisms in wheel and axle plant for achieving smooth and trouble free operation.

BACKGROUND ART

Wheels are produced by forging process. After processing and heat treatment, wheels are further fed to SAWH (Semi automatic wheel handling) system for processing the wheel in the CNC (Computerized Numerical Control) machine. The machining section consists of fifteen nos. of CNC for its process. It is divided into two lines.Line1 consists of machines from No.1 to No.7. The forged wheel undergoes its one side of machining through these seven machines. Then the wheels got transferred and reversed by transfer car and shifted to Line 2 machines for further machining. Line2 consists of machines from No.8 to No.15. The forged wheel undergoes its other side of machining through these 8 machines. The wheels go for quality testing after finishing on both the sides. Each fifteen nos. of machines are provided with Semi Automatic Wheel Handling system for putting the wheels on to the VTB (Vertical turning and boring) bed and moving out for further queued up processes. Each SAWH comprises of a number of wheel handling mechanisms. Tilting bed Collects the forged wheel from overhead cranes and feeds to the charging bed. Charging bed consists of motorized rollers (set of 5 AC motors) and is used as an input tray for the machining process. Moving Cart is responsible for grab up/down and moving forward/reverse for placing the wheel at its desired location. Moving Trolley is used for moving the wheel from the VTB to the discharge bed. Discharge bed consists of motorized rollers (set of 5 AC motors) and serves as an output tray for the machining process. In the process of SAWH, First Wheels are placed on the charging bed through tilting bed (for Line 1) or through transfer car (for Line 2). Second Loading Process, under which Moving Cart lowers down, grabs the wheel from the charging bed and places it on the VTB bed for machining.

Third unloading process, which takes place after CNC operation and moving cart again grabs the wheel from the VTB bed and places it on the moving trolley in forward position. The trolley at its reverse position rolls the wheel on the discharge bed. Wheels are then collected from the discharge bed by the transfer car. The system mainly comprises three types of movement namely roller conveyor by AC motors, Cart movement and up and down movement by hydraulic system.

In the prior art, each process is individually operated and controlled by the local pulpit with the help of Siemens S-5 100 U Controllers. The local pulpits and field equipments are connected with existing controllers in a hardwired manner through multicore control cables. The handling process gets hampered due to problem in any of the mechanism involved. The fault finding is difficult in the existing control system. This causes a lot of delay. At the same time, there is no centralized monitoring facility for the wheel handling system.

Such conventional wheel handling system suffers from drawbacks / disadvantages which are discussed hereunder:
A. Online monitoring of wheel handling during the plant operation is not possible because the controllers have no such features.
B. It is very difficult to find any fault related to number of field sensors and signals used in automation system.
C. Rectification of any fault and its cause analysis is not possible due to absence of event logging in the old system.

OBJECTS OF THE INVENTION

It is therefore the principle object of the present invention is formation of PLC-RIO based control system scheme for wheel handling operation at finishing lines of WAP. Another object of the present innovation is to development of algorithm for auto wheel loading and auto wheel unloading.

Yet another object of the present invention is the development of use friendly SCADA (Supervisor Control and Data Acquisition) screens that is capable to minimize manual intervention.

Further object of invention is network architecture design for centralized monitoring and control facility and to generate MIS (Management Information System) as a control and monitoring tool for higher management.

SUMMARY OF THE INVENTION

Thus, according to the present invention there is provided a system for Centralized monitoring and Control for wheel handling in finishing lines at Wheel and Axle plant, which is reliable and provides smooth wheel handling operation as desired for finishing of wheels by CNC machines.

Such as herein described a system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant comprises of:
a plurality of PLC Processors for wheel handling mechanisms of two lines of surface finishing; a plurality of Remote Input Output based units with profinet scanner module configured for communication with CPU and RIO in ring network, Power supply module, Digital input Module and Digital output modules for interfacing the field process and feedback signals to the processor; a plurality of field sensors like Limit switches, Pressure switches, Solenoids configured for generating a reference signal generation to the controller for process control and command signals are generated as per logic by the PLC to start particular drive associated with the said mechanisms; a centralized monitoring and control unit including an operator desk, 24 nos. of Push buttons, 2 nos. of selector switches, 6 LED indications and emergency switch adapted to interface the machine and switch over to different modes of operation; and a networking architecture wherein the PLC and RIOs are networked in ring topology with profinet protocol and the PLCs are connected on Ethernet protocol.

With the present invention the Centralized monitoring and Control for wheel handling in the finishing sections of the wheel handling system has been possible with high level of precision and minimum breakdown.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 illustrates different mechanisms involved in wheel handling system in the present system in block diagram form;

Figure 2 illustrates a schematic block diagram of system for centralized monitoring and control for wheel handling in finishing lines in WAP in accordance with the present invention;

Figure 3 illustrates few photographs of the panels of PLC/RIO system, Communication Panel and Operator Desk used in the present invention;

Figure 4 illustrates few display Screens system developed in the present invention;

DETAILED DESCRIPTION

Herein disclosed is a system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant for achieving smooth and trouble free operation.

The system has been implemented in finishing section of the wheel handling plant of DSP (Durgapur Steel plant ) of SAIL (Steel Authority of India Limited) where both the sides of the heat treated cold black wheel are machined in CNC as per the design specification of wheel. The system consists of combination of hardware and software. The following are the hardware components used for the disclosed centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant:
i) Two numbers of PLC CPU (Central Processing Unit), power supply modules, profinet controller modules for communication with RIOs and various switchgears.
ii) Fifteen numbers of RIOs (Remote Input Output) panels: Rugged, industrial grade conforming to IP-42 standard based units with profinet scanner module used for communication with CPU and RIO in ring network, Power supply module, Digital input Module and Digital output modules for interfacing the field process and feedback signals. The seven numbers of RIO panels connected to one PLC via a communication interface in one of the finishing line of SAWH System. The eight numbers of RIO panels connected to second PLC via a communication interface in other finishing line of SAWH System.
iii) Fifteen numbers of ODs (Operator Desks): Rugged, industrial grade enclosure conforming to minimum IP-42 standard, each operator desk consists of 24 nos. of Push buttons, 2 nos. of selector switches, 6 LED indications and emergency switch that help the operator to interface the machine and switch over to different modes of operation (Auto, manual, Semi auto etc).

iv) Field sensors like Limit switches, Pressure switches, and solenoids are mostly used as a reference signal generation to the controller for process control and Command signals generated as per developed logic by the PLC to start particular drive associated with mechanisms. Limit switches mainly used for giving the feedback about the positions of grab lower, grab raised, cart parking, cart above trolley and VTB, trolley at outgoing Conveyor. Trolley position at VTB, Tilting bed horizontal and tilted positions etc; Pressure switches used for indication grab fully open and fully closed; Solenoids are used to actuate commands like grab up , grab down, Grab open and close, tilting bed raise and lower, mobile hydraulic pack loading, stationary hydraulic pack loading etc.
v) Software for PLC programming to accomplish the desired sequential wheel handling operation. The software is able to program the PLC as per designed algorithm and features of online data monitoring are there.
vi) HMI (Human machine Interface) / SCADA; this software is basically to design various display screens and capable of online and historical data logging.
vii) Software for Web access: Browser based Web accessible display screens have been designed in a separate terminal in which web access software has been installed. These screens are available in plant wide net and higher authority may monitor the system from any terminals of plant LAN (Local area network) provided permission has been granted.
viii) Cables of various types and Ethernet switch: Various types of cables used matching to the communication protocol used. CAT 5E shielded twisted pair cable have been used between the PLC and RIO to form a ring network. Ring network provides the redundancy in communication as any cut in cable does not impact data transfer. The PLC system is connected with PCs (programming terminal and HMI terminals) through OFC via an industrial ethernet switch. The maximum OFC length between PLC and switch is approximately 400m. The distance is the main reason that CAT 5E shielded twisted pair cable was not used. OFC used is multicore, multimode, outdoor type. For signal transmission to and from field devices; Multicore, multistrand armored copper control cables has been used.
The number of the hardware components may increase and/or decrease as per the posed requirement in the WAP (Wheel and axle Plant). The numbers has been provided only for the purpose of explanation only. A person skilled in the art will be able to understand the enhanced and distinguishing effect made through the said Centralized system and the usefulness of the disclosed system. It will be appreciated by the person of skill in the art that various addition / alteration may be made to the

above described embodiments without departing from the scope of the present disclosure.

Figure 1 describes the sequential mechanism involved in wheel handling system like tilting bed operation, roller motors, Cart movement, grab movement, transfer trolley movement etc. Cart movement is done by hydraulic mobile power pack and tilting bed movement is done by stationary hydraulic power pack. Specifications of roller motors, mobile power pack motor and stationary power pack motors are described in figure1. To eliminate the limitations of the prior art at Wheel and Axle plant (WAP), state-of-the art PLC - RIO based centralized monitoring and control system is introduced to reduce the delay in the wheel handling system. Provision of centralized monitoring facilities at Electrical shift room as well as monitoring facility at web accessible HMI screens are also provided.

Figure 2 describes the schematic of the centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant, in which two numbers of PLC CPUs are placed in 4th and 11th machine , while rest of the machines are connected by RIO panels with corresponding CPUs. Both the PLCs are connected to the HMI terminals, programming terminals and Plant net through an industrial Ethernet switch. The major components of the system are as follows:

Control system

Two nos. of PLC and exactly saying PAC (GEIP make), one for each finishing line to take care of the control function of respective finishing line have been introduced. All the mechanisms (described in figure1) of wheel handling system for finishing the wheel in CNC machines shall be controlled by the PLC. The first finishing line comprises of one PLC and seven numbers of RIO Panels. PLC panel installed at machine no.4 of the finishing line. This PLC panel has necessary IO modules to take care of input output signals of operations related to that CNC machine. One RIO take care of input output signals of operations related to one CNC machine means IOs are terminated to local RIO panels situated near to the machine. All RIOs are connected to PLC panel with the Ethernet based ring type communication network. Similarly, Second finishing line comprises of one PLC and eight numbers of RIO Panels. PLC panel installed at machine no. 11 of second finishing line.

PLC subsystem

It consists of GEIP PAC (Programmable automation Controller) Systems; Controller environment that combines performance, productivity, flexibility and openness. It involves GEIP RX3I 7 slot rack, which is used for the interfacing between the housed modules. The rack houses RX3I 24V power supply for powering the modules and PAC System RX3i CPU with 1.1 GHz processor. CPU has got 5Mbytes of user memory and 5Mbytes of flash memory. The Rack also has GEIP RX3I Profinet Controller used for interconnection between RIOs through PNS (Profinet Scanners).

RIO Subsystem

It consists of GEIP Versamax I/O Carrier in which input and output modules are mounted. GEIP Profinet Scanner PNS is used for interfacing between PNC (Profinet controllers) and RIO over Ethernet ring topology. 32 Channel Versamax DI and DO modules are used. The system consists of 15 nos. of RIO system, for Line 1(RIO1 to RIO7) and for Line 2 (RIO8 to RIO15). RIO 4 and RIO 11 are integrated with PLC CPUs of Line 1 and Line2 respectively. Each PLC and RIO systems are interconnected over Ethernet cables in a ring network topology.

HMI Subsystem:

It is used for monitoring the process through animation, report generation etc. this subsystem comprises of two sections. First one is PROFICY CIMPLICITY section for process and status monitoring. Second is WEBACCESS section, which is a browser based monitoring, meant for status monitoring through local mode and remote mode i.e. from any authorized PC connected to the plant intranet. Proficy machine edition of GEIP is used for ladder development package.

Centralized monitoring facility in shift room and web accessible screens:

Both The PLCs in the finishing line of semi automatic wheel handling system is connected to an engineering station placed in the Electrical Shift Room (ESR). The Engineering station has been used as a programming terminal for developing the programming software of PLC. The uploading, downloading, testing etc done from this station. This station is connected with the PLCs through an open protocol communication link (Ethernet) via OFC, suitably laid through GI conduit pipe. This

terminal also acts for centralized monitoring and control purpose. The said facility has number of screens for operator interface and monitoring and control of wheel handling processes. Web accessible screen server has Web accessible Screens for monitoring purpose. The screens are accessed by thin client through web browser from nodes on Plant LAN. Connection is established with plant wide LAN for this purpose and a separate web server used for deployment of web accessible screens. Web accessible screen server and Engineering Station connected to both the networks i.e. PLC network and DSP LAN as required. Node point for DSP LAN is available in the Electrical Shift Room. An industrial network switch is used for interconnectivity between PLCs, Engineering Station and Server for web accessible screens.

Operator Desk system:

The operator desks have numbers of push buttons, selector switches, indicating display, emergency switch etc for operation of wheel handling system from an individual CNC machine location. There are total 15 (Fifteen) numbers of such ODs corresponding to every finishing point for the wheels.

Communication Interface:

Ethernet communication between PLC and drives is healthy. Both the ports on either side of the Ethernet cable should appear as green in colour to indicate its healthiness. OFC (optical fibre Cable) has been laid from each master PLC Panel of line 1 and line 2 to the communication panel in the electrical shift office. The protocol used here is S90 Triplex. This is an open protocol for SCADA (Supervisory Control and Data Acquisition). Automation system includes a communication panel with two numbers of fibre optics splicing Cassette for FO termination and two numbers of multi modes FO to Ethernet media converter.

Usefulness of the Invention

In summary, the new system has better monitoring and fault diagnosis features. The state of the art centralized monitoring and control for wheel handling system at Wheel and Axle Plant is having latest PLC of GEIP, Which has faster processing speed and advanced memory management. It has an energy pack for backup during power failure. The ring network technology over Ethernet protocol always has its advantage of redundancy in communication. The remote monitoring and control

system helps fault diagnosis and data loggings as and when necessary. The interconnection between Web access and Plant Intranet enables any user on the Plant intranet system to view the status signal, of course helpful to management to monitor the process at distant location. The faster and advanced PLC will improve the system performance. The system is mainly conceptualized to reduce the breakdown, reduce the time to diagnose the fault in case of breakdown and subsequent delay in the Semi automatic wheel handling system in CNC area of Wheel and Axle Plant. Such innovations in which a small investment can bring a significant benefit are to be considered in future at different areas of plant. The benefits realized from this invention may reduce the cost of production of wheel and thus increase the profitability of the plant.

Industrial Applicability

A system has been designed and developed in house for the wheel handling system in finishing sections of wheel and axle plant at Durgapur steel plant of SAIL (Steel authority of India Ltd). Procurement of Miscellaneous equipments of different make, software etc used has been done by RDCIS (Research and development centre of Iron and steel), SAIL and System has been installed and commissioned at WAP (Wheel and Axle plant), DSP (Durgapur steel plant). Similar scheme can be implemented in such areas of Steel plants or any Industry where multiple machines are involved in same type of operation. The new system will have distinct advantages over the old one in terms of reliability, user friendliness and maintainability. Easy fault diagnosis in case of any electrical breakdown in any of the machines. The breakdown in the concerned area is in downward trend. Chances of unintentional errors will be less and any change in operation logic will be easy to implement through soft logic.

Numerous modifications may be made to the present invention, which still fall within the intended scope hereof. Thus, it should be apparent that there has been provided in accordance with the present invention a system for centralized monitoring and control for wheel handling in finishing line at the wheel and axle plant that fully satisfies the objectives and advantages set forth above. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.