This document describes an external plunge grinding machine automated with a control panel using a Mitsubishi PLC system. It discusses how programmable logic controllers have improved manufacturing productivity by providing flexible, reliable control. The PLC controls inputs like push buttons and outputs like motors and lights. Ladder logic programming is used to automate the machine's grinding and loading/unloading sequences. Servo and induction motors precisely position the grinding wheel. A human-machine interface allows users to input part programs. Communication between the PLC and computer allows storing and monitoring machine data. Overall, automating the machine's control panel with a PLC improves productivity and efficiency compared to traditional control techniques.

1. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –
6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 4, July-August (2013), © IAEME
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AN EXTERNAL PLUNGE GRINDING MACHINE WITH CONTROL PANEL
AUTOMATION TECHNIQUE BASED ON MITSUBISHI PLC SYSTEM
1
Arvind N. Nakiya, 2
Mahesh A. Makwana, 3
Ramesh R. Gajera
1
Department of Electrical Engineering, Nirma University, Ahmedabad, India
2
Department of Mechanical Engineering, SVNIT, Surat, India
3
Department 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
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2. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –
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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

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

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

8. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –
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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.
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[4] Mrs.Jignesha Ahir,Viren Pandya, and Chintan Mehta, Design and Development of PLC and
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