Plc Report

 

Application of PLC in Factory Automation  & Computer Integrated Manufacturing                         

Under  the  guidance  of    Mr. J S

Dhaka

Sr. Manager –Operations & H.O.D (Jewel Box Section) Moser Baer India Limited Greater Noida      

Submitted By

                                                                               

 

Rajat Gupta Bachelor of Technology Electronics Engg. HBTI Kanpur

 

Acknowledgement   

I would like to express my heartfelt gratitude to MOSER BAER INDIA LIMITED on successful completion of my Summer Internship Program. It was a pleasure to work with an organization of such a stature. Firstly I would like to thank the Department of Training for organizing the Induction program giving insight not only to the company , it’s operations , its values and visions but also to the technology ,its scope and the future. I would like to thank Mr. Manoj Shekhawat (AGM-Training), Mr. Sanjay Negi and Mr. Kamal for their supervision and care during my entire stay with MBIL. I am deeply indebted to Mr. Omveer Singh (Dy. Manager) and Mr. J S Dhaka (Sr. Manager & H.O.D) of the Jewel Box section for their guidance and their support and for helping me with my problems and doubts. I would not have been able to complete this project without their valuable efforts and guidance.                      

 

About Moser Baer    

Moser Baer, headquartered in New Delhi, is one of India's leading technology companies. Established in 1983 as a Time Recorder unit in technical collaboration with Maruzen Corporation, Japan and Moser Baer Sumiswald, Switzerland, the company successfully developed cutting edge technologies to become the world's second largest manufacturer of Optical Storage media like CDs and DVDs. The company also emerged as the first to market the next-generation of storage formats like Blu-ray Discs and HD DVD. Recently, the company has transformed itself from a single business into a multi-technology organisation, diversifying into exciting areas of Solar Energy, Home Entertainment and IT Peripherals & Consumer Electronics. Moser Baer has a presence in over 82 countries, serviced through six marketing offices in India, the US, Europe and Japan, and has strong tie-ups with all major global technology players. Moser Baer has the distinction of being preferred supplier to all top global OEM brands. Moser Baer stands committed to supplying highest quality fully licensed media to its customers. Moser Baer's products are manufactured at its three state-of-the-art manufacturing facilities. It has over 6,000 full-time employees and multiple manufacturing facilities in the suburbs of New Delhi.        

 

Moser Baer milestones   1983

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Established

1985

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Production of 8.0"/5.25" Disks

1987

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Production of 3.5" Disks

1998

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ISO 9002 Certification

1999

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Production of CD-R

2000

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Production of CD-RW

2002

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Completely Integrated Manufacturing

2003

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Production of DVD-R Production of DVD-RW ISO Certification for all Facilities Launch of 'Moserbaer' Brand in Indian Market Signed one of Largest Outsourcing Deals in Indian Manufacturing

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2004

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2005

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'Lightscribe' Deal with HP HP Deal for India and SAARC Region Contributing Member of Blu-Ray Disk Association ISO 14001 & OHSAS 18001 certification for Moser Baer plants. Commencement of Phase III of Greater Noida Plant Announced Moser Baer Photovoltaic Ltd as it's wholly owned subsidiary Received status of SEZ developer from Govt. of India Announced a wholly owned subsidiary-Moser Baer SEZ

 

Signed MoU with IIT, Delhi 2006

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2007

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2008

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The first company in the world to start volume shipments of HD DVD-R Signed Technology MoU with IT BHU Patented technology approved by the Blu-ray Disc Association In-house R&D Centre approved by Ministry of Science and Technology Launched USB Flash drives Forayed into entertainment space, enters Home Video market Acquired OM&T BV - a Philips' optical technology and R&D subsidiary Announced start of trial run of solar photovoltaic cell production facility Set up the world's largest Thin Film Solar Fab Launched US$150 mn FCCBs Moser Baer Photo Voltaic announced commercial shipment of solar photovoltaic cells Moser Baer Photo Voltaic announced US$880 million strategic sourcing tie-up with REC Group Forayed into PC peripherals market: Launches Optical Disk Drives (ODDs), Headphones, Keyboards, Optical Mouse etc. Launched Branded DVD Player Moser Baer plans 600 MW Thin Film PV capacity with an estimated investment of over $ 1.5 bn Moser Baer Photo Voltaic announces strategic sourcing tie-up with LDK Solar Moser Baer announces successful trials of first Gen 8.5 Thin Film plant

 

Introduction to PLC’s   

General-purpose sequencers (programmable logic controllers) have, in the 1990s, come into widespread use as critically important elements in many areas of factory automation (FA) and computer integrated manufacturing (CIM). Thanks to an increasingly sophisticated range of functions that include calculation, information processing and networking support, they can be found throughout industry controlling manufacturing processes, assembly, inspection and transportation. Day by day PLC manufacturers are configuring and optimizing to attain total FA systems imposing additional demands upon these sequencers for more functional operation and the extension of their application to the control of electric power distribution, building supervision and management, and simple instrumentation installations.The result is that present day PLC’s are more functional,more performaning, smaller , having networking capabilities and better built-in intelligence. These days software control and dual CPU’s are being used to achieve high reliability, ease of maintenance, and to provide diagnostic functions.

A PLC (i.e. Programmable Logic Controller) is a device that was invented to replace the necessary sequential relay circuits for machine control. The PLC works by looking at its inputs and depending upon their state, turning on/off its outputs. The user enters a program, usually via software, that gives the desired results. PLCs are used in many real world applications. If an industry’s processes involve machining, packaging, material handling, automated assembly or countless other facilities , they find a PLC application. Almost any application that needs some type of electrical control has a need for a plc.    

 

PLC History   

In the late 1960's PLCs were first introduced. The primary reason for designing such a device was eliminating the large cost involved in replacing the complicated relay based machine control systems. Bedford Associates (Bedford, MA) proposed something called a Modular Digital Controller (MODICON) to a major US car manufacturer. Other companies at the time proposed computer based schemes, one of which was based upon the PDP-8. The MODICON 084 brought the world's first PLC into commercial production. These "new controllers" also had to be easily programmed by maintenance and plant engineers. The lifetime had to be long and programming changes easily performed. They also had to survive the harsh industrial environment.The answers were to use a programming technique most people were already familiar with and replace mechanical parts with solid-state ones. In the mid70's the dominant PLC technologies were sequencer state-machines and the bit-slice based CPU. The AMD 2901 and 2903 were quite popular in Modicon and A-B PLCs. Conventional microprocessors lacked the power to quickly solve PLC logic in all but the smallest PLCs. As conventional microprocessors evolved, larger and larger PLCs were being based upon them. However, even today some are still based upon the 2903.(ref A-B's PLC-3) Modicon has yet to build a faster PLC than their 984A/B/X which was based upon the 2901. The 80's saw an attempt to standardize communications with General Motor's manufacturing automation protocol(MAP). It was also a time for reducing the size of the PLC and making them software programmable through symbolic programming on personal computers instead of dedicated programming terminals or handheld programmers. Today the world's smallest PLC is about the size of a single control relay.    

 

PLC Internal Structure  The PLC mainly consists of a CPU, memory areas, and appropriate circuits to receive input/output data. We can actually consider the PLC to be a box full of hundreds or thousands of separate relays, counters, timers and data storage locations. The counters, timers, etc. don't "physically" exist but rather they are simulated and can be considered software counters, timers, etc. These internal relays are simulated through bit locations in registers.

 

ROLE OF EACH PART:    •

INPUT RELAYS­ (contacts)These are connected to the outside world. They physically exist and receive signals from switches, sensors, etc. Typically they are not relays but rather they are transistors. 

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INTERNAL UTILITY RELAYS-(contacts) These do not receive signals from the outside world nor do they physically exist. They are simulated relays and are what enables a PLC to eliminate external relays. There are also some special relays that are dedicated to performing only one task. Some are always on while some are always off. Some are on only once during power-on and are typically used for initializing data that was stored.

    •

COUNTERS­These again do not physically exist. They are simulated counters and they can be programmed to count pulses. Typically these counters can count up, down or both up and down. Since they are simulated they are limited in their counting speed. Some manufacturers also include high-speed counters that are hardware based. We can think of these as physically existing. Most times these counters can count up, down or up and down.  

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TIMERS­These also do not physically exist. They come in many varieties and increments. The most common type is an on-delay type. Others include off-delay and both retentive and non-retentive types. Increments vary from 1ms through 1s.

   

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OUTPUT RELAYS(coils)These are connected to the outside world. They physically exist and send on/off signals to solenoids, lights, etc. They can be transistors, relays, or triacs depending upon the model chosen.

•

DATA  STORAGE­Typically there are registers assigned to simply store data. They are usually used as temporary storage for math or data manipulation. They can also typically be used to store data when power is removed from the PLC. Upon power-up they will still have the same contents as before power was removed.              

 

PLC Operation  A PLC works by continually scanning a program. We can think of this scan cycle as consisting of 3 important steps. There are typically more than 3 steps but these there encapsulate the essence of the operation . Typically the others are checking the system and updating the current internal counter and timer values.  

                                                 

 

 

Step 1-CHECK INPUT STATUS-First the PLC takes a look at each input to determine if it is on or off. In other words, is the sensor connected to the first input on? Then the second input? Then the third and so on…. It records this data into its memory to be used during the next step. Step 2-EXECUTE PROGRAM-Next the PLC executes your program one instruction at a time. Maybe the program says that if the first input was on then it should turn on the first output. Since it already knows which inputs are on/off from the previous step it will be able to decide whether the first output should be turned on based on the state of the first input. It will store the execution results for use later during the next step.

 

Step 3-UPDATE OUTPUT STATUS-Finally the PLC updates the status of the outputs. It updates the outputs based on which inputs were on during the first step and the results of executing your program during the second step. Based on the example in step 2 it would now turn on the first output because the first input was on and your program said to turn on the first output when this condition is true. After the third step the PLC goes back to step one and repeats the steps continuously. One scan time is defined as the time it takes to execute the 3 steps listed above.

 

PLC Programming  Programmable controllers are generally programmed in ladder diagram (or "relay diagram") which is nothing but a symbolic representation of electric circuits. Symbols were selected that actually looked similar to schematic symbols of electric devices. There are several languages designed for user communication with a PLC, among which ladder diagram is the most popular. Ladder diagram consists of one vertical line found on the left hand side, and lines which branch off to the right. Line on the left is called a "bus bar", and lines that branch off to the right are instruction lines.

At Moser Baer Jewel Box section Mitsubishi’s MELSEC-A series controllers and AD-75 positioning systems are used. Mitsubishi provides sequence control instructions and microcomputer basic programs which can be had from A1SD75M1/M2/M3 , AD75M1/M2/M3 positioning module User manual and programming manual. Due to the company’s policy against disclosure the instruction set and working programmes of the

 

implemented systems cannot be included in this report. However , the basic classification and application has been laid out. The function and device use ranges and determine by parameter values. Parameters of CPU are set by default values. If the default can be used for the purpose and it is not necessary to set the parameter.

INSTRUCTIONS:- The instructions of MELSEC-A series are largely classified into sequence instruction, and application instruction. However instructional programming is now seldom done at Moser Baer as implementation is by modular programming using library and software package provided by Mitsubishi. Only when a new assembly is being implemented which finds a new routine of events , does instructional programming takes place which can also be saved as a new module and hence can be used later on with new programs. The PLC softwares nowadays have drag and drop features in which modules can be dragged and dropped in plans. It is just like Proteus and MATLAB where we can use standard electronics components and connect them thru wires. Here, we can use library or self made modules and can interconnect them as in diagram. This feature is very much useful in high level assemblies where otherwise the manhours required will be high.

 

 

PLC  application  at  Jewel  Box  Assembly  Lines : Positioning Module   

While PLC’s are controller devices , positioning module is the actual device that does the mechanical action .It basically controls mechanical movement of servo motors under guidelines laid by PLC. It can be understood by CPU-Printer head relationship. CPU converts Text Data to be printed into postscript which basically outlines the data and at what place of page it is to be printed. Accordingly the printer guides the head precisely to that position and prints the characters sequentially. While the CPU is analogous to PLC , the printer is analogous to POSITIONING MODULE.

The positioning module used by Moser Baer’s Jewel Box section is AD-75 . The basic positioning mechanism using AD-75 is given below. Positioning control using the AD75 is carried out with "SSCNET". In the positioning system using the AD75, various software and devices are used for the following roles. The AD75 realizes complicated positioning control when it reads in various signals, parameters and data and is controlled with the PLC CPU. Because of the SSCNET connection type, the AD75 outputs to the servo amplifier the data (position/speed commands) resultant from conversion of pulse trains into numerical values.) In numerical data-based commands and pulse train-based commands, the concepts of the movement amount and speed are the same. FUNCTIONS OF 1.) GPP function software package : Creates control order and conditions as a sequence program. 2.) PLC CPU : Stores the created program. The AD75 outputs the start signal and stop signal following the stored program. AD75 errors, etc., are detected.

 

3.) AD75 software package : Sets the parameters and positioning data for control. Outputs the start command for test operation with the test mode. Monitors the positioning operation. 4.) External signal : Inputs signals such as the start signal, stop signal, limit signal and control changeover signal to the AD75.

5.) Manual pulse generator : Issues commands by outputting pulses.

 

6.) AD75 positioning Module : Stores the parameter and data. Outputs position/speed command to the servo according to the instructions from the PLC CPU, AD75 software package, external signals and manual pulse generator 7.) Servo amplifier : Receives commands from AD75, and drives the servomotor. Outputs the monitor data that indicates the servo amplifier status. 8.) Servomotor & Workpiece : Carries out the actual work according to commands from the servo amplifier.

In positioning accuracy is a very important feature. While high precision position control is required for applications which are miniature, having nuances and fineness, high precision speed control is essential for mass production. Beyond one point we can tradeoff one for the other but this itself has an upper ceiling. AD -75 does speed control and position control in the following manner

ф Position control The total number of pulses in a pulse train required to move the designated distance is obtained in the following manner.

 

When this total number of pulses in a pulse train is issued from the AD75 to the servo amplifier, control to move the designated distance can be executed. The machine side movement amount when one pulse is issued to the servo amplifier is called the "movement amount per pulse". This value is the min. value for the workpiece to move, and is also the electrical positioning precision. ф Speed control The above "total number of pulses in a pulse train" is an element required for movement distance control, but when carrying out positioning control or speed control, the speed must also be controlled. This "speed" is controlled by the "pulse train frequency". The outline of the positioning system operation and design, using the AD75, is shown below.

 

Purpose and applications of positioning    

"Positioning" refers to moving a moving body, such as a workpiece or tool at a designated speed, and accurately stopping it at the target position. The main application examples are shown below. 1.) PUNCH PRESS (X, Y feed positioning)

• To punch insulation material or leather, etc., as the same shape at a high yield, positioning is carried out with the X axis and Y axis servos. • After positioning the table with the X axis servo, the press head is positioned with the Y axis servo, and is then punched with the press. • When the material type or shape changes, the press head die is changed, and the positioning pattern is changed.

 

2.) Palletizer

• Using the servo for one axis, the palletizer is positioned at a high accuracy. • The amount to lower the palletizer according to the material thickness is saved.

 

3.) Compact machining center (ATC magazine positioning) • The ATC tool magazine for a compact machining center is positioned. • The relation of the magazine's current value and target value is calculated, and positioning is carried out with forward run or reverse run to achieve the shortest access time.

 

4.) Lifter (Storage of Braun tubes onto aging rack) • During the aging process of braun tubes, storage onto the rack is carried out by positioning with the servo. • The up/down positioning of the lifter is carried out with the 1-axis servo, and the horizontal position of the aging rack is positioned with the 2-axis servo

 

5.) Index table (High-accuracy indexing of angle) • The index table is positioned at a high accuracy using the 1-axis servo.

 

6.) Inner surface grinder • The grinding of the workpiece's inner surface is controlled with the servo and inverter. • The rotation of the workpiece is controlled with the 1-axis inverter, and the rotation of the grinding stone is controlled with the 2-axis inverter. The workpiece is fed and ground with the 3-axis servo.