INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING ... EXTERNAL PLUNGE G… · International Journal...

International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –

6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME

197

AN EXTERNAL PLUNGE GRINDING MACHINE WITH CONTROL PANEL

AUTOMATION TECHNIQUE BASED ON MITSUBISHI PLC SYSTEM

1Arvind N. Nakiya,

2Mahesh A. Makwana,

3Ramesh R. Gajera

1Department of Electrical Engineering, Nirma University, Ahmedabad, India

2Department of Mechanical Engineering, SVNIT, Surat, India

3Department of PHE&T, FPTBE, AAU, Anand, India

ABSTRACT

Automation is the process of handling various parameters of process like temperature, flow,

level etc. without presence of responsible person. In industrial field, Automation and control have

greatly improve in industrial manufacturing in the world Technological advancement in automation

and control over the past decades have contributed greatly to improve the productivity of virtually all

manufacturing industries throughout the world. In the development of automation controllers the

trend has been to move towards soft controllers so as to provide better control, more flexibility and

more reliability with intelligent diagnostics of machine faults. So industries have gradually moved

from conventional relay logic control to programmable logic control and then to computerized

numeric control. In this paper all the required control, induction and servo motor performance data

with ladder logic programming will be taken to a personal computer via PLC for further analysis.

Various results are obtained and discussed.

Keywords: External plunge Grinding machine (EPG), Programmable Logic Control (P.L.C.),

induction motors, Personal Computer (PC), Servo motor, variable frequency drives, voltage control

1. INRODUCTION

Almost any production line, machine function or process can be automated using a PLC. The

speed and accuracy of the operation can be greatly enhanced using this type of control system. The

use of programmable logic controllers (PLCs) with power electronics in electric machines

applications has been introduced in the manufacturing automation [1]. But the biggest benefit in

using a PLC is the ability to change and replicate the operation or process while collecting and

communicating vital information. Since there were problems related to large electrical panels with a

number of electrical components and extensive wiring, people felt the need for software logic

controllers? So they gave birth to Programmable Logic Controller (P.L.C) wherein the control logic

INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING &

TECHNOLOGY (IJEET)

ISSN 0976 – 6545(Print)

ISSN 0976 – 6553(Online)

Volume 4, Issue 4, July-August (2013), pp. 197-204

© IAEME: www.iaeme.com/ijeet.asp

Journal Impact Factor (2013): 5.5028 (Calculated by GISI)

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IJEET

© I A E M E



198

is developed in ladder diagram, a software logic control, with a number of inputs taken from the

environment and generating the outputs, depending on the logic programmed, to the environment.

This helped to control any machine sequence with small electrical panels, less number of electrical

components and less wiring with more flexibility to change machine sequence. These fulfilled some

of their needs but the desire to obtain software controlled automation with accuracy necessitated the

development of Human Machine Interface (HMI). In order to have better control for positioning,

controlled speed and quick reversal of direction of slide movement, servo and induction motors

having less inertia, along with servo drives are interfaced with the HMI. The user based part program

decoded by the HMI provides the desired graphical profile with the control being transferred to

P.L.C. and drives as and when required [2].

2. PROGRAMMABLE LOGIC CONTROLLER

A programmable logic controller is a specialized computer. Since it is a computer, it has all

the basic component parts contained in any other computer, a central processing unit, memory, input

interfacing, and output interfacing.

Fig.1: Block Diagram of PLC

The block diagram of Programmable Logic Controller is shown in Fig.1 the processor is a

solid state device designed to replace relays, timers, counter etc. The necessary voltage and current

requirement for the internal working of the PLC is generated by the power supply. The field element

is interfaced to the input or output section. Typical input or output section, typical input element are

push buttons, limit switches, proximity switches, relay contacts, selector switches, thumb wheels etc.

Typical output elements are solenoid valves relay coils, indicator lights LED display etc. Fig.3 shows

PLC based control panel system for external plunge grinding machine. In this control panel system

Mitsubishi Q series PLC is used.PLC controls all inputs and outputs. Wheel is fed directly into the

work piece in external plunge grinding. In this paper external plunge grinding is used for bearing

application [2].

Fig.2: Block Diagram of experimental set up



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A flowchart is ideal for a process that has sequential process steps. The steps will be executed

in a simple order that may change as the result of some simple decisions. The symbols used for

flowcharts are shown in Figure2. These blocks are connected using arrows to indicate the sequence

of the steps. The different blocks imply different types of program actions.

Fig.3: PLC based control panel for EPG

3. OPERATION OF SERVO MOTOR

Ac servo motors are used in ac servomechanisms and computers which require rapid and

accurate response characteristics. To obtain these characteristics, servo motors have small-diameter

high-resistance rotors. The small diameter provides low inertia for fast starts, stops, and reversals,

while the high resistance provides a nearly linear speed-torque relationship for accurate control.

Servo motors are wound with two phases physically at right angles or in space quadrature. Servo

motors feature a fixed or reference winding is excited from a fixed voltage source, while the control

winding is excited by an adjustable or variable control voltage, usually from a servo amplifier. The

servo motor windings are usually designed with the same voltage-turns ratio.

Fig.4: A. C. Servo motor of EPG machine

So that power inputs at maximum fixed-phase excitation and at maximum control-phase

signal are in balance. In an ideal servo motor, torque at any speed is directly proportional to the servo

motor's control winding voltage. In practice, however, this relationship exists only at zero speed

because of the inherent inability of an induction servo motor to respond to voltage input changes



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under conditions of light load. The inherent damping of servo motors decreases as ratings increase

and the servo motors have a reasonable efficiency at the sacrifice of speed-torque linearity.

Fig.5: Servo motor wiring

As sown in fig 6 sequence of operation of servo motor is as below

Step 1: Start Operation / Zero Position

A If Push Button Start OPR = ON Then JOG = ON (Manual Operation to LS Zero)

B If LS Zero = ON Then Start OPR = ON in Positioning Module QD75M1

C Waiting Servo to Positioning Operation Complete

Step 2: Positioning Start

A If Push Button Start = ON Then Positioning Start No.1 = RUN (To 20mm) And Waiting

Positioning Complete.

B If Positioning Complete = ON Then Positioning Start No.2 = RUN (To 40mm) And Waiting

Positioning Complete.

In this project used two servo motors, One for X-axis and other for y-axis. The capacity or x-axis

motor is three phase, 123V, 6A, 1KW, and 2000rpm and for y-axis is three phase, 146V, 17A,

3.5KW, and 2000rpm.

Fig.6: Operation of servo motor



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4. VFD CONTROL

The circuit shown in fig.7 is control the direction of rotation and speed of 3-phase induction

motor by using VFD.230 V, 50Hz, 1 Phase supply is given across NO contact of relay(terminal A

and C of VFD) Terminal SD is Common to the contact input terminal and terminal FM. Common

output terminal for 24VDC 0.1A power output. SD terminal is connected to the selector switch 1.

Terminal R, S, T is used as input and U, V, W is used as output which is connected to motor. In this

there are two control methods (1) control by Auto (2) Control by Manually. In manually control,

selector switch2 is connected across STF and STR terminal of VFD which is used for changing

direction of rotation.1W, 2K ohm frequency setting potentiometer is connected across terminal 10, 2,

5 of VFD which is used to adjust input voltage and frequency setting of inverter. In automatic control

we push the start forward push button on SCADA, relay R3 is energized and motor rotate in forward

direction and pushing start reverse button on SCADA ,relay R4 is energized and motor rotate in

reverse direction. Speed of motor is control by Analog output of PLC. Servo drives are used in

conjunction with servo motors for better variable speed control with less response time as the inertia

of the rotor is less [3]. Fig 8 sows how servo drive is connected with PLC. For this connection servo

amplifier is connected between servomotor and PLC.

Fig.7: VFD control wiring Fig.8: Servo drive connection

5. PROGRAMMING AND COMMUNICATION

5.1 Ladder Program The ladder program is then executed rung-by-rung. Scanning the program and solving the

logic of the various ladder rungs determine the output states. The updated output states are stored in

fixed memory locations (output image memory Q). The output values held in memory are then used

to set and reset the physical outputs of the PLC simultaneously at the end of the program scan [4].

The host computer provides the software environment to perform file editing, storage, printing, and

program operation monitoring. The process of developing the program to run on the PLC consists of:

using an editor to draw the source ladder program, converting the source program to binary object

code which will run on the PLC’ s microprocessor and downloading the object code from the PC to

the PLC system via the serial communication port [5].



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Here in this experimental set up work, the inputs and outputs selection are given below.

Inputs

X20-Gauge out X2E-Single cycle

X21-Gauge in X2F-Multi cycle

X22-Loader in X30-Auto dressing PB

X23-Loader out X31-Wheel on/off

X24-Loader up X32-W/H on/off

X25- Magnet on/off X33- Loader down

X26-Un loader down X34-Gauge in/out PB

X27-Un loader up X35-Diamond roll on/off

X28-Un loader in X36-Rough end IP

X29-Un loader out X37-Finish end IP

X2A-Oil level ok X38-Cycle end IP

X2B-Oil PS X39-Un loader in/out PB

X2C-Size +PB X3A-Loader up/down PB

X2D-Size -PB X3B-Un loader up/down PB

Outputs

Y41-Wheel Y4E-Break release

Y42-Work head Y4F-Oil lamp

Y43-Diamond roll motor Y50-Homing lamp

Y44-Lubrication motor Y51-Loader ok lamp

Y45-Magnet Y52-Loading lamp

Y46-Demagnetizer Y53-Alarm lamp

Y47-Coolant Y54-Cycle lamp

Y48-Loader down Y55-Yellow lamp

Y49-Un loader up Y56-Red lamp

Y4A-Loader out Y57-Gauge end valve

Y4B-Un loader out Y58-Gauge start

Y4C-Job clamp valve Y59-Gauge return

Y4D-Job stop valve

Fig 9 shows, how induction motor control through ladder logic programing by PLC. Initially

I0 status bit is a logic because the normally closed (NC) stop pushbutton is closed I0.2 status bit is a

logic because the normally closed (NC) overload relay (OL) contacts are closed I0.0 status bit is a

logic 0 however because the normally open start pushbutton has not been pressed. Normally open

output Q0.0 contact is also programmed on network as a sealing contact. With this simple network

energizing output coil Q0.0 is required to turn on the motor. When the start pushbutton is pressed the

CPU receives logic from input I0.0. This causes the I0.0 contact to close. All three inputs are now

logic. The CPU sends logic to output Q0.0. The motor starter is energized and the motor starts.

Fig.9: Motor Starts



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5.2 Communication between PLC and computer The RS-232 standard is based on a low/false voltage between +3 to +15V, and an high/true

voltage between -3 to -15V (+/-12V is commonly used).Fig 10 shows some of the common

connection schemes. In all methods the txd and rxd lines are crossed so that the sending txd outputs

are into the listening rxd inputs when communicating between computers. When communicating

with a communication device (modem), these lines are not crossed. In the modem connection the dsr

and dtr lines are used to control the flow of data. In the computer the cts and rts lines are connected.

These lines are all used for handshaking, to control the flow of data from sender to receiver. The

null-modem configuration simplifies the handshaking between computers. The three wire

configuration is a crude way to connect to devices and data can be lost. Many PLC processors have

an RS-232 port that is normally used for programming the PLC.

Fig.10: Common RS-232 Connection Schemes

For man machine interface LCD as shown in fig.11 is used.

Fig.11: LCD Screen

6. RESULTS

Many PLC processors have an RS-232 port that is normally used for programming the PLC.

In Fig 12 Mitsubishi Q series PLC is connected with personal computer. For operation of machine

required data for user is store as a form of programme in the PLC via PC. In programming result Fig

13 sows that in ladder rung 262, NO contact start, with contact MO, M7 and input X25, magnet is

on/off. Similarly in fig 14 sows at rung 218, with loader out input contact X29, after 10S, loader is

out.



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Fig.12: Mitsubishi PLC with PC

Fig.13: Experimental result for magnet on/off Fig.14: Experimental result for loader out

7. CONCLUSION

After the above discussion we can conclude that by automation of PLC panel of EPG

machine we can improve the Productivity in the industry. Also it is faster and more efficient than the

classical techniques. By automation of PLC panel we continuously monitor the state of input devices

and makes Decisions based upon a custom program to control the state devices connected as Output.

REFERENCES

[1] G. Kaplan, Technology 1992 Industrial electronics, IEEE Spectre. Vol. 29, pp. 47–48, Jan.

1992.

[2] Arvind N. Nakiya, Mahesh A. Makwana, An Overview of PLC Based Control Panel System

for External Plunge Grinding Machine and CNC Machine, International Journal of Modern

Engineering Research, Vol.2, Issue.6, Nov-Dec. 2012.

[3] Douglas V. Hall, Microprocessors and Interfacing (Programming and Hardware), Tata

McGraw-Hill, 1992.

[4] Mrs.Jignesha Ahir,Viren Pandya, and Chintan Mehta, Design and Development of PLC and

SCADA Based Control Panel for Continuous Monitoring of 3-Phase Induction Motor, National

Conference on Recent Trends in Engineering & Technology at B V M college,

V.V.Nagar,Gujarat,India, 13-14 May 2011.

[5] Yasar birbir, H.Selcuk Nogay, Design and Implementation of PLC-Based Monitoring Control

System for Three-Phase Induction Motors Fed by PWM Inverter International Journal Of

Systems Applications, Engineering & Development, Issue 3, Volume 2, 2008.

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