Project Report-Design of a PLC System for health monitoring of DC drive through SMS final

“Design of a PLC System for health monitoring of DC drive
through SMS”
A PROJECT REPORT
Submitted in partial fulfillment of the
requirement for the award of the
Degree of
BACHELOR OF TECHNOLOGY
IN
ELECTRICAL AND ELECTRONICS ENGINEERING
by
(Abhishek Sharma- 10BEE1009)
Under the Guidance of
Mr. Guru K Prasad Prof. Nilanjan Tewari
External Guide Internal Project Supervisor
SCHOOL OF ELECTRICAL ENGINEERING
VIT University
CHENNAI-600127, Tamil Nadu, India
MAY 2014

CERTIFICATE
This is to certify that the project work titled “Design of a PLC System
for health monitoring of DC drive through SMS” submitted by
“Abhishek Sharma” is in partial fulfillment of the requirements for the
award of BACHELOR OF TECHNOLOGY DEGREE, is a record of bona fide
work done under my /our guidance. The contents of this project work, in
full or in parts, have neither been taken from any other source nor have
been submitted to any other Institute or University for award of any
degree or diploma and the same is certified.
Guru K Prasad Nilanjan Tewari
External Guide Internal Project Supervisor
ABB India Ltd.
(Organization stamp)
The thesis is satisfactory / unsatisfactory
Internal Examiner External Examiner
Approved by
Dean
School Of Electrical Engineering

IF THE CANDIDATE HAS DONE HIS /HER PROJECT OUTSIDE THE
VIT UNIVERSITY A CERTIFICATE TO THAT EFFECT MUST BE
ATTACHED HERE ON THE ORGANIZATION’S LETTER HEAD DULY
STAMPED and SIGNED

I would like to dedicate this project to my project guides, my parents and my
abled professors who have given their best efforts in making it possible.

ACKNOWLEDGEMENTS
I would like to thank VIT for imparting me knowledge and skills required for my
current endeavors. I also want to thank ABB India Ltd., Bangalore for providing me the
opportunity to intern at Peenya premises and providing me all possible technical assistance
during the training period. I would like to especially thank my mentor- Mr. Guru K Prasad for
his timeless help, apt guidance and motivation despite of health adversaries. I feel fortunate to
have Mr. Ramdas and Mr. Harish for my help from Discrete Motion PLC department. I
would take this opportunity to thank them for all technical assistance I received from them. I
want to pay my special thanks to Mr. Vadiraj (Low Voltage Drives department) for arranging
the drive and providing technical input. Without the support of above mentioned people, it
would have been impossible to complete the project on time.
In addition, I would like to heartily thank Prof. Nilanjan Tewari for his unparalleled
guidance, availability, technical assistance and encouragement. Finally but most importantly,
I thank my parents, respected dean- Prof. Hemamalini, program chair- Prof. Senthil Kumar
and entire SCHOOL OF ELECTRICAL ENGINEERING for providing me this chance and
for supporting me throughout the course.
(Abhishek Sharma)
10BEE1009

ABSTRACT
Control has been a necessary part of every process involved in a day to day life. Use of
analog controllers is conventional but they are difficult to design and reduce flexibility in
operation of system. Hence, digital control systems are gaining prominence for industrial
control applications. One of the applications of digital control is monitoring of industrial
process or systems. There are various options available for implementation of control but the
PLC (Programmable Logic Controller) emerges as the most viable option for industrial
applications. In this project a PLC system is designed to regularly monitor the health of a
remotely located DC drive used for applications like pumping, nuclear waste processing,
manufacturing automation, etc. Assigning this task to an employee is costly, monotonous and
inefficient way. Thus by automating the monitor and operations process, this project aims to
obviate the need of humans in monitoring and responding to any inadvertent contingency.
This project was proposed to monitor speed, efficiency, torque, output power, input power,
and ripple factor of a DC drive. The system also detects over-current fault, temperature
related fault, overvoltage and under-voltage faults. In this condition the drive is stopped and
the user is notified of the type of fault occurred through an SMS on his mobile phone. The
user is also informed of runtime, average value of torque, current, voltage, speed and
efficiency daily. In the second review further extension to this project was proposed. The
extension included control of the DC drive system through SMS. However due to lack of
time for testing, the desired results were not achieved.

LIST OF TABLES
Table 1 Drive runtime data when current is kept constant 26
Table 2 Drive runtime data when applied voltage is kept constant 28

LIST OF FIGURES
Fig. 1 AC500 PM573 ETH Programmable logic controller 2
Fig. 2 Sectional view of DC550 DC drive 3
Fig. 3 AI561 analog input module 4
Fig. 4 Maestro Heritage GSM modem with attachments 4
Fig. 5 Process flow in the RTU 7
Fig. 6 Process flow at base data station 8
Fig. 7 Command flow for GSM modem 9
Fig. 8 Block design: send value of torque 9
Fig. 9 Block design: send value of speed 10
Fig. 10 Block design: send value of drive efficiency 10
Fig. 11 Block design: send value of input power 11
Fig. 12 Block design: send value of output power 11
Fig. 13 Block design: motor speed calculation 12
Fig. 14 Block design: motor torque calculation 12
Fig. 15 Block design: output power calculation 13
Fig. 16 Block design: input power calculation 13
Fig. 17 Block design: Efficiency calculation 14
Fig. 18 Block design: Overvoltage and under voltage fault monitoring 14
Fig. 19 Block design: Overcurrent fault monitoring 15
Fig. 20 Block design: Overheat fault monitoring 15
Fig. 21 Control builder plus configuration for COM ports 16
Fig. 22 Hardware overview of the project 17
Fig. 23 Hardware setup 18
Fig. 24 Result: Message received “voltage fluctuation out of range” 21
Fig. 25 Result: Message received “overcurrent fault occurred” 22
Fig. 26 Result: Message received “Drive is running at speed (RPM) 600 23
Fig. 27 Result: Message received “Drive efficiency is 91” 23
Fig. 28 Result: Message received “Motor torque is 33.5” 24
Fig. 29 Result: Data received on hyper terminal by data center 25

Fig. 30 Voltage v/s speed variations keeping current constant 27
Fig. 31 Voltage v/s Efficiency variations keeping current constant 27
Fig. 32 Current v/s Torque keeping operating voltage constant 28
Fig. 33 Current v/s Speed keeping operating voltage constant 29
Fig. 34 Efficiency v/s Current keeping operating voltage constant 29
Fig. 35 Speed – Torque curve of the motor 30

LIST OF ABBREVIATIONS
DC - Direct current
ETH - Ethernet
PLC - Programmable logic controller
RTU - Remote terminal unit
DM - Discrete motion
I/O - Inputs/Outputs
I/P - Input
O/P - Output
SCADA - Supervisory control and data acquisition
ANN - Artificial network
GPRS - Global radio packet service

NOTATIONS
 is the armature current
 is the developed torque
 and are motor parameters
 is armature resistance
 is armature voltage

 is efficiency of the system

TABLE OF CONTENTS
LIST OF TABLES (if any) viii to ----
LIST OF FIGURES ---- to ----
LIST OF ABBREVIATIONS -----to ----
NOTATION -----to ----
CHAPTER 1 Introduction Page Nos
1.1 Objective and goal of the project 1
1.2 Literature survey 1
1.3 Hardware description
1.3.1 PM 573 ETH PLC 2
1.3.2 ABB DCS550 drive 2
1.3.3 AI 531 four input analog module 3
1.3.4 Maestro Heritage GSM modem 4
CHAPTER 2 Background
2.1 Compatibility and developments 5
2.2 Mathematical Formulae 5
2.2.1 Motor torque developed 5
2.2.2 Angular speed 5
2.2.3 Output power 6
2.2.4 Input power 6
2.2.5 Efficiency 6
CHAPTER 3 Design and methodology
3.1 Methodology 7
3.1.1 Process components of remote terminal unit (RTU) 7
3.1.2 Base data station process components 8
3.1.3 RS232 based AT command parsing for GSM modem 8
3.2 Software design 9

3.2.1 Design of the block to send value of torque 9
3.2.2 Design of block to send motor speed 10
3.2.3 Design of block to send drive efficiency 10
3.2.4 Design of block to send input power 11
3.2.5 Design of block to send output power 11
3.2.6 Design of block to calculate motor speed 12
3.2.7 Design of block to calculate motor torque 12
3.2.8 Design of block to calculate output power 13
3.2.9 Design of block to calculate input power 13
3.2.10 Design of block to calculate efficiency 13
3.2.11 Design of block for voltage fault monitoring 14
3.2.12 Design of block for overcurrent fault monitoring 15
3.2.13 Design of block for temperature monitoring 15
3.3 COM port setting for RS232 communication 16
3.4 Hardware design 16
3.5 Variable declaration and initialization 18
CHAPTER 4 Results and discussions
4.1 Hardware results 20
4.1.1 Results for fault monitoring 20
4.1.2 Drive runtime information – Mobile phone 22
4.1.3 Data collection results – Hyperterminal 25
4.1.4 Graphical results 26
CHAPTER 5 Conclusion and scope of improvement
5.1 Conclusion 30
5.2 Applications of the developed system 31
5.3 Scope of improvement 31

CHAPTER 1
INTRODUCTION
------------------------------------------------------------------------------------------------
1.1 Objectives and goal of the project
Current projects aims at software design and hardware implementation of a
programmable logic control (PLC) system for health monitoring of a direct current (DC)
drive through simple message service (SMS). This system is designed to monitor the
various operational parameters of DC drive including speed, efficiency, torque, output
power, input power, and ripple factor. The proposed system can be used to monitor a
group of remotely located drives operating continuously without much changes in
operational schedule.
The design is primarily proposed to counter the problems like ignorance of human
supervisor and high operational cost. It also ensures fault monitoring and enables
economic optimization of the system. By automating the monitoring system better
performance can be achieved and incipient damage to the operating system can be
achieved. The proposed design holistically acts as a remote terminal unit (RTU) and
keeps sending the runtime information to user and data center.
1.2 Literature Survey
Programmable logic controllers have been incessantly used in industrial applications for
control and monitoring. SCADA based systems are used in modern power systems for
power flow polling and contingency/fault monitoring. R. Isermann [1] has proposed a
model for condition monitoring of actuators, machineries, drives, plants, sensors and fault
tolerant systems. This work also proposes various models for fault diagnosis of DC
drives. The current project utilizes the mathematical model developed in this worked for
calculation of various parameters displayed in results. Singh and Nandanwar [2] presents
a microcontroller based approach for performance monitoring of DC motor. The main
drawback of this system is the limited and small amount of memory and processing
capability available on chip. Also, microcontrollers are incapable of real-time data

processing and efficient handling of analog data. Thus, digital signal processors (DSP)
emerge as viable option. However, DSPs have limitations related to communication with
other units and number of inputs and outputs. Therefore, PLC appears to be the most
viable option with high clock speed, inherent ability for analog data and real-time data
processing, multiple modes of communication (Profibus, Modbus, serial, parallel and
ethernet) and easily expandable I/O cards. All these advantages make PLCs highly
suitable for supervisory control and monitoring of industrial installations. Ionnides [3] has
also used PLC for designing monitoring control system for induction motor. Current work
tries to combine the above work and adopts a new approach for data transmission using
SMS to increase the range and effectiveness of data transfer to the terminal unit.
1.3 Hardware Description
1.3.1 PM 573 ETH PLC
AC 500 series of PLCs are currently being used by ABB in various installations. The PLC
used in this project is PM573 with onboard Ethernet for communicating with a PC or OPC.
The I/Os can be extended by adding available modules as required.
Fig. 1 AC500 PM573 ETH Programmable logic controller
1.3.2 ABB DCS 550-20 drive

ABB DCS 550 is an ideal solution and a replacement of analog devices for OEM machine
manufacturers. It has compact design to suit installations with limited space. It is compatible
with a wide range of available motors because of its integrated three phase field exciter
ranging up to 35 A. It also has a “winder” with commissioning assistant for easy adaption to
various applications. It offers great integration in automation through various fieldbus
interfaces including EtherCAT, PROFINET. It can be adaptively programmed with Drive
AP, ABB’s graphical PC-tool for easy implementation of additional functions. In addition to
this, it has various start-up assistants and auto-tune functions for fast commissioning along
with a large control panel for straight forward and self-explanatory operation. Besides this it
has a rugged design for rough environments and which ensures high reliability.
Fig.2 Sectional view of DC550 DC drive
1.3.3 AI 531 four analog input module
This Analog Input Module AI531 is used as a remote expansion module with PM573 for
acquiring the analog values of current and frequency from DCS550. It has four configurable
inputs (I0-I3) in one group. It can be interfaced using TU515 for connecting with the PLC.
These inputs are not electrically insulated from each other. Following figure displays the
AI561 module.

Fig. 3 AI561 analog input module
1.3.4 Maestro Heritage GSM modem
The Heritage GPRS modem from Maestro Wireless Solutions combines a base unit offering
GSM/GPRS/EDGE technologies in an Industrial grade design with pluggable boards catering
for diverse Machine to Machine applications. It is OpenAT Compatible, which means it can
be programmed using Wavecomm AT commands. It also supports expansion boards
including Industrial Grade I/Os, Ethernet and GPS. The following figure displays Maestro
Heritage GSM modem with its attachments.
Fig. 4 Maestro Heritage GSM modem with attachments

CHAPTER 2
BACKGROUND
------------------------------------------------------------------------------------------------
2.1 Compatibility and developments
The system developed in this project derives its technical grounds from the research
publications mentioned in chapter 1.2. The developed system is designed to support DCS550
and DCS800 series of DC drives developed and marketed by ABB Ltd. The various inputs
and outputs of the system have been parameterized to support multiple drives with a wide
range of motors. The software configured system developed in this project is versatile and
highly adjustable according to the need of time. In the following section, extracts from
previous publications regarding derivations have been mentioned.
2.2 Mathematical formulae
The formulae utilized in this project have been derived to minimize the number of inputs and
reduce the computational complexity. For the same reason, a time domain based approach
has been adopted. These calculations can be altered for different motor and drive
combinations.
2.2.1 Motor Torque developed
This formula have been used to find out the motor torque developed.
------------------ (2.1)
 Where, and are motor parameters
 is the developed torque
2.2.2 Angular Speed

To calculate the angular speed, following relation has been used.
-------------------
(2.2)
 Where, and are motor parameters
 is armature resistance
 is armature voltage

2.2.3 Output Power
The output power is calculated by using the relation:
------------------- (2.3)
 Where T is torque

2.2.4 Input Power
Following relation is used to determine the input power:
-----------------------
(2.4)
 Where V is armature voltage
 is armature current
2.2.5 Efficiency
Efficiency of the system is governed by the relation:
-------------------------- (2.5)

 Where is efficiency of the system
CHAPTER 3
DESIGN & METHODOLOGY
------------------------------------------------------------------------------------------------
In this section the software design of the project and the algorithm based on which the design
is concurred are discussed. Later, the hardware design is discussed and a complete overview
of the project is provided.
3.1 Methodology
Current project follows a simple design methodology. It is a hardware-software correlated
design hence the hardware required to accomplish the project is also dependent on the
software design. The following flow charts depicts the flow of information and instructions in
the system.
3.1.1 Process components of remote terminal unit (RTU)
The following figure depicts the components of the process performed by the RTU in a
stepwise pattern.
Fig. 5 Process flow in the RTU
First the data is acquired from the drive through AI531 analog input module. It can be done
using either parallel communication or MODBUS communication. In this project parallel

communication is supposed. This data is sampled and used for real time data processing. The
value of variables thus received are then used for calculations of various parameters like
torque, angular speed, etc. The value of these parameters can be sent out either using RS 485
or RS 232 or using Ethernet interface. However, in this project a novel approach is proposed
for sending the data through SMS and GSM based interface. For this the PLC communicates
with the modem through a modified RS232 interface. This enables flexibility with distance
and maintenance.
3.1.2 Base data station process components
The following figure depicts the process flow at the base data station in a step wise pattern.
Fig. 6 Process flow at base data station
In addition to the user, base station receives the operation data continuously where it may be
stored for retrospection. The base station receives this data through COM2 port of the PLC
through serial communication or through MODBUS. These values are then processed and
stored at the data center for viewing later and analyzing the performance of the system.
3.1.3 RS232 based AT command parsing for GSM modem
The GSM modem receives the AT commands through serial communication via COM1 port
of the PLC. Simultaneous communication with the GSM modem and the data center is
possible since the field bus used in both these interactions are different. The GSM modem
receives the commands, parses them and follow the instructions provided to send the SMS to
the user. The following figure shows the order in which instructions are passed to the GSM
modem.

Fig. 7 Command flow for GSM modem
3.2 Software Design
The above algorithm is now implemented for parametric calculations and fault monitoring.
The software design has been accomplished using Codesys and ABB control builder is used
for configuring the PLC to perform according to the user’s wish. In the following sub
sections, design of individual blocks have been discussed and displayed.
3.2.1 Design of the block to send value of torque
Using the previously discussed mathematical formulae, a block is developed to send the
motor torque in SMS. The software design of this block is provided in Fig. 8.
Fig. 8 Block design: send value of torque

Above block checks for the value of voltage and current to be in range. If the values are in
range, it sends the value of calculated torque to the user’s mobile phone.
3.2.2 Design of block to send motor speed
Using the previously discussed mathematical formulae, a block is developed to send the
motor speed. The software design of this block is provided in Fig. 9.
Fig. 9 Block design: send value of speed
range, it sends the value of calculated motor speed to the user’s mobile phone.
3.2.3 Design of block to send drive efficiency
Using the previously discussed mathematical formulae, a block is developed to send the drive
efficiency in SMS. Software design of this block is provided in Fig. 10.
Fig. 10 Block design: send value of drive efficiency

Above block checks if the value of voltage and current are in allowable range or not. If the
values are in range, it sends the value of calculated motor efficiency to the user’s mobile
phone.
3.2.4 Design of block to send input power
From the set of formulae provided previously, a block is designed to send input power.
The software design of this block is provided in Fig. 11.
Fig. 11 Block design: send value of input power
range, it sends the value of input power to the user’s mobile phone.
3.2.5 Design of block to send output power
From the set of formulae provided previously, a block is designed to send the value of output
power. The software design of this block is provided in Fig. 12.
Fig. 12 Block design: send value of output power

range, it sends the value of input power to the user’s mobile phone.
3.2.6 Design of block to calculate motor speed
Using the previously discussed mathematical formulae, a block is developed to calculate
motor speed and pass it on to the communication block. The software design of this block is
provided in Fig. 13.
Fig. 13 Block design: Motor speed calculation
This block calculates the value of speed from input current and input voltage of the drive.
3.2.7 Design of block to calculate motor torque
From the set of formulae provided previously, a block is designed to calculate the value of
torque developed by the motor. Fig. 14 shows the software design of the block created for
this purpose.
Fig. 14 Block Design: Motor torque calculation

This block calculates the value of torque from input current and drive parameters and passes
on the value to the communication block which dispatches the message to the user’s mobile
phone.
3.2.8 Design of block to calculate output power
Using the mathematical formulae discussed in chapter 2, a block is developed to calculate
output power and pass it on to the communication block. The software design of this block is
provided in Fig. 15.
Fig. 15 Block design: Output power calculation
This block calculates the value of output power from calculated torque and speed. It works
regardless of whether it is a normal condition or a fault condition.
3.2.9 Design of block to calculate input power
From the set of formulae provided in chapter 2, a block is designed to calculate the value of
input power of the motor. Fig. 16 shows the software design of the block created for this
purpose.
Fig. 16 Block design: Input power calculation
This block calculates the value of input power from input voltage and input current. It works

3.2.10 Design of block to calculate Efficiency of the system
Using the mathematical formulae discussed in chapter 2, a block is developed to calculate the
drive efficiency and pass it on to the communication block. The software design of this block
is provided in Fig. 17.
Fig. 17 Block Design: Efficiency calculation
This block calculates the value of efficiency from input power and output power. It works
3.2.11 Design of block for overvoltage and under voltage fault monitoring
From the set of formulae provided in chapter 2, a block is designed to calculate the value of
input power of the motor. Fig. 18 shows the software design of the block thus created.
Fig. 18 Block design: Overvoltage and under voltage fault monitoring
This block continuously checks whether the value of voltage is in specified limits. When the
limits of voltage are crossed, the block stops the drive and alerts the user of the fault by
sending an SMS to his mobile phone.
3.2.12 Design of block for overvoltage and under voltage fault monitoring

Using the mathematical formulae discussed in chapter 2, a block is developed to calculate the
drive efficiency and pass it on to the communication block. The software design of this block
is provided in Fig. 19.
Fig. 19 Block design: Overcurrent fault monitoring
The above block continuously checks whether the value of current is under specified limit.
When the limit of current is crossed, the block stops the drive and alerts the user of the fault
by sending an SMS “Overcurrent fault” and value of current to his mobile phone.
3.2.13 Design of block for temperature monitoring
The software design of this block is provided below.
Fig. 20 Block design: Overheat fault monitoring
The above block continuously checks whether the temperature of the drive is under specified
limit. When the limit of temperature is crossed, the block stops the drive and alerts the user of
the fault by sending an SMS “Temperature exceed the normal temperature” and value of
current to his mobile phone.
3.3 COM port setting for RS232 communication

Following is the setting done for COM1 and COM2 for extending RS232 communication
with the GSM modem. The data format used is 8N1 with no flow control. This enables the
PLC to communicate with GSM modem and to pass on the AT commands through serial
communication. This way a master-slave setup is established and exchange of data is
enabled. The connection is made through DB9 male to male connector.
Fig. 21 Control builder plus configuration for COM ports
3.4 Hardware design
Hardware design of this system can be broken into two parts:
 Control system design
 Communication System design
For communication design SMS_ALERT library was designed to be used for controlling
GSM modem serially through the PLC. Control system design on the other hand consists of a
network of DC drive, PLC and sensors. In the following section, hardware overview of the
project is provided and images of the real setup are provided. The following diagram denotes
the hardware overview of the project.

.
Fig. 22 Hardware overview of the project
The DCS550 drive is interfaced with the analog module which connected to the PLC through
TU515 base module. The outputs of the drive is output current and voltage. In the first phase,
data acquisition is done through the AI531 four input analog modules. Once these values are
acquired, they are passed on to the PLC and parametric calculations are carried out.
In the second phase these values are prepared and dispatched for communication through the
modem. The signal originating from the modem is wirelessly received by the Base
Transceiving Station (BTS). From the BTS, this data is passed on to Base Switching Circuit
(BSC) which searches the location of intended receiver. From the BSC the data is passed on
to the Main Switching Circuit (MSC) which has the info of the mobile subscriber. This way
MSC decides the destination BSC of the SMS. Now the message is transmitted through the
message center after IMSI check of the receiver. When the IMSI of the TU matches with the
IMSI details encrypted in the com signal, the incoming message is accepted. After receiving
the information packet, the decoder located on the mobile device decodes the message into a
readable data. This data is also simultaneously sent to the data center which records all the
information and events for retrospection. The hardware setup of the project is displayed in
Fig. 23.

Fig. 23 Hardware setup
3.5 Variable declaration and initialization
PROGRAM PLC_PRG
VAR
voltagefluct: SMS_ALERT; // Declaration of various SMS alerts
torque_send: SMS_ALERT;
overcurrentalert: SMS_ALERT;
Efficiency_send: SMS_ALERT;
Speed_send: SMS_ALERT;
ip_send: SMS_ALERT;
op_send: SMS_ALERT;

overheatalert: SMS_ALERT;
Vref: REAL:=100; // Input and references declaration
Iref: REAL:=20;
In_voltage: REAL:=100;
In_current:REAL:=29;
Ke: REAL:= 0.95; // motor constants declaration
Kf: REAL:=0.88;
Ra: REAL:=0.5;
Speed:REAL;
Torque: REAL; // motor calculaton declaration
In_power: REAL;
Output_power:REAL;
Efficiency: REAL;
temp: REAL;
fs: R_TRIG; // trigger and timer declaration
fs1: R_TRIG;
fs2: R_TRIG;
time1: TON;
timestart: TON;
time2: TON;
timeelapsed: TIME;
Complete: BOOL; // done flag declaration
Complete1: BOOL;
Complete2: BOOL;
Complete3: BOOL;
complete4: BOOL;
Phone_number_invalid: BOOL;

Com_port_invalid: BOOL; // invalid results declaration
Phone_number_invalid1: BOOL;
Com_port_invalid1: BOOL;
Phone_number_invalid2: BOOL;
Com_port_invalid2: BOOL;
END_VAR
VAR_OUTPUT
Drive_Stop: BOOL; // emergency output declaration
END_VAR
CHAPTER 4
RESULTS AND DISCUSSIONS
------------------------------------------------------------------------------------------------
In this chapter, results obtained after hardware implementation are displayed. In
addition to it the generated trends are generated from the data obtained and plots
are displayed.
4.1 Hardware results
The project is proposed for monitoring DC drives located at remote areas. The same system
was designed and implemented and following results were concurred. The results were at par
with the design objectives and the system developed is compatible with 57X, 58X series of
PLC and has compatibility with DCS550 and DCS800 series of DC drives. The user and the
data center can receive the various parameters sent by the RTU.
4.1.1 Results for fault monitoring
In this section, results for fault monitoring of DC drive including results for Overvoltage and
under-voltage fault monitoring, overcurrent fault monitoring and temperature monitoring
blocks are discussed. Following images display the message received on mobile phone and
hyper terminal in case an under voltage or an overvoltage fault occurs in the system.

Fig. 24 Result: Message received “voltage fluctuation out of range”
As seen from Fig. 24, when the voltage fluctuations go out of range, i.e. when the drive
speeds up or down beyond the recommended values, it is stopped and an error message is
received by the user. This informs the user of possible fault related to voltage and thus
mitigates any possible damage to the system.
Similarly, when the armature current exceeds the max possible allowable value of current of
the drive, it is protected by braking the power supply to the drive and informing the user by
an SMS as shown in Fig. 25. This way over current protection is offered by the system for the
drive. Similar to these two faults, temperature of the drive is also monitored by a digital
temperature sensor which checks whether the operating temperature is in the permissible
limits. If the operating temperature crosses the reference (set value) of maximum allowable
temperature, the system disconnects the drive and informs the user by sending an SMS
“Drive temperature exceeded”.

Fig. 25 Result: Message received “overcurrent fault”
4.1.2 Drive runtime information – Mobile phone
In the following section, results for displaying runtime information to the user as a summary
for the day are provided. When no contingency occurs i.e. when the voltage and current do no
exceed the preset values, a message regarding drive’s speed, efficiency, input power, output
power and torque is sent out to the user.
As seen in Fig. 26 the drives running speed is displayed along with the instance at which the
value was recorded. This keeps the user aware of the drive speed constantly through a simple
message. The system can be programmed to send hourly, daily or every minute update of the
drive speed to the user. In the background, the available block diagram for this particular
function is provided. In a separate block calculations are done and passed on to the
communication block. The SMS_ALERT block then sends the SMS to the user’s mobile
phone as well as to the data center which uses Hyper terminal for view ASCII data being sent
through RS232 based serial communication.

Fig. 26 Result: Message received “Drive is running at speed (RPM) 600
Similarly in Fig. 27 the result displaying the drive efficiency are provided. The system
calculates the drive efficiency and sends it to the user and hyperterminal from where trends
can be generated.
Fig. 27 Result: Message received “Drive efficiency is 91”

Fig. 28 displays the information about the generated torque received by the user through
SMS. The same information is also sent to hyper terminal for generating trends if required.
The following figure displays the data “summary” as received by the data center through
COM2 communication port.
This summary consists of input power, output power, speed and torque of the motor attached
to the drive. The drive can be programmed to give either 0-10V TTL logic or 400mA current
based logic for providing to I/Os.
Fig. 28 Result: Message received “Generated torque is 33.5”
This sums up the hardware results as obtained on the user’s mobile phone. In the following
sections the results obtained on the hyperterminal and graphical results obtained through this
data are displayed.

4.1.3 Data collection results – Hyperterminal
The following section, screenshots of how the summary (runtime data) is received by the data
center are provided. Using MS Excel, a macro was created to import the data in a datasheet
which is later used to generate trends at the data center.
Fig. 29 above, displays the summary received by the hyper terminal continuously in a time
period of two seconds. It also displays the number to which the message regarding summary
is sent along with the instant of sending
Fig. 29 Result: Data received on hyper terminal by data center
All the results were verified both through the hyperterminal as well as mobile phone. The
system is tested to perform well with AC500 PM57X and PM58X series along with DCS500
or DCS800 drives.

4.1.4 Graphical results
In this section, various plots obtained are displayed and discussed. These trends are plotted in
MS excel after data collection through macro. These are helpful in evaluating drive
performance and fault monitoring. The data simulated from the drive are provided in Table 1.
Table 1 Drive runtime data when current is kept constant
Graph shown in Fig. 30 is obtained by keeping the drive current constant and varying the
voltage of the drive using a potentiometer. The corresponding values of current speed is
calculated and are plotted against the values of operating voltage.
Voltage Current Speed Input power Output power efficiency
20 20 58 400 200 50
25 20 87 500 300 60
30 20 117 600 400 66.66
35 20 146 700 500 71.4
40 20 175 800 600 75
45 20 204 900 700 77.7
50 20 234 1000 800 80
55 20 263 1100 900 81.8
60 20 292 1200 1000 83.3
65 20 321 1300 1100 84.6
70 20 351 1400 1200 85.7
75 20 380 1500 1300 86.7
80 20 409 1600 1400 87.5
85 20 438 1700 1500 88.2
90 20 468 1800 1600 88.9
95 20 497 1900 1700 89.5
100 20 526 2000 1800 90

Fig. 30 Voltage v/s speed variations keeping current constant
As evident from Fig. 30, when the drive operating speed is increased in a step size of 5 volts,
the speed of the motor increases linearly.
In Fig. 31, trend for voltage and efficiency are provided. The set voltage range is 20-
120 volts and maximum allowable current is set at 20 amperes. For current trends, the value
of current was set at 20 amperes and voltage is varied in a range of 20-120 volts. Maximum
efficiency achieved was 91 percent at 100 volts.
Fig. 31 Voltage v/s Efficiency keeping current constant

Now, the operating voltage is kept constant and drives operating data is recorded. The
recorded data is displayed in Table 2.
Voltage
(V)
Current
(Amps)
Torque
(N-m)
I/P power
(watts)
O/P power
(watts)
Speed
(rpm)
Efficiency
(%)
100 4 13.68 400 392 2865 98
100 8 54.72 800 768 1403 96
100 12 123.12 1200 1128 916 94
100 16 218.88 1600 1472 672.5 92
100 20 342 2000 1800 526 90
Table 2 Drive runtime data when applied voltage is kept constant
From the data in Table 2 various characteristics are derived. Some of these characteristics are
discussed in following section.
Fig. 32 displays a plot between current and torque. It is evident from Fig. 32 that the value of
motor torque has a quadratic relation with the armature current.
Fig. 32 Current v/s Torque keeping operating voltage constant

Fig. 33 Current v/s Speed plot keeping operating voltage constant
Fig. 33 displays the relation between armature current and motor speed. It displays and
inverse quadratic relations. This means when the current is increased (implies that load is
increased), the speed of the motor decreases to make the generated torque equal to the load
torque.
Fig. 34 Efficiency v/s Current plot keeping operating voltage constant

While keeping the operating voltage constant, efficiency is calculated for different values of
current. This is an inverse linear relation as displayed in Fig. 34. As the load on the system
increases the efficiency of the system decreases due to higher losses.
Fig. 35 Torque- speed curve of the motor
In Fig. 35, torque speed characteristics of the system are displayed. As seen from Fig. 35, the
motor speed is inversely proportional to the motor torque. All the data analyzed in this report
was collected from DCS550 DC drive and through simulation in Codesys.

CHAPTER 5
CONCLUSION AND SCOPE FOR IMPROVEMENT
----------------------------------------------------------------------------------------------------------------
5.1 Conclusion
The proposed system is designed to mark up the objectives. The system is tested to work with
PM 573 and PM 583 PLCs. The designed system is also expected to work appropriately with
DCS550 and DCS800 series of DC drives by ABB. The system successfully monitors for any
fault condition and intimates the user in case of any fault.
The developed system works successfully according to the objectives laid at the beginning of
the project. It increases the flexibility, connects remote areas where equipment is installed
and saves time and labor. The system offers low computational complexity, high chances of
integrity and provides sufficient supervision and monitoring. All these factors makes it a
popular choice in industrial automation. However, the effectiveness of this system can be
enhanced by making a few additions. Such possible amendments and scope of this project are
proposed in the following section.
5.2 Applications of the developed system
Current project finds its applications in myriad directions. Nuclear power plants, mining
industries, chemical industries, water pump house, industrial automation, remotely located
transmission towers and transformers are a few applications of this project. By making subtle
changes in the software, it can be adjusted to suit any need of supervisory control and
monitoring.
5.3 Scope of improvement
 The RTU developed in this project is not completely wireless. It uses COM2 serial
communication interface to interact with the data center. This limits the range in
which the RTU can be installed since serial communication suffers major attenuation
when data is required to be sent at large distances. By using a 3G router, GPRS based

connectivity can be established between RTU and data center. Thus, the range can be
maximized and losses can be mitigated.
 The current system does not monitors any mechanical faults or incipient faults which
may lead to an electrical fault. These mechanical faults can be monitored using the
machine learning based approach adopted by Abhishek et al. [4]. However, a few
improvements to the system are required to train the system to perform in various
possible conditions.
 Current work only focuses on development of an individual RTU. Based on this
system a SCADA system can be developed for remote monitoring.
 A SMS based control system can be developed based on this work which enables the
user to also control the drive wirelessly by sending an SMS.
 The designed system can be upgraded to enable fault diagnosis. Current system is
only limited to fault monitoring and detection. However, a more challenging task is to
diagnose where the fault has occurred in the circuit and how the fault can be cleared.
For this wavelet transform methods, ANN based methods and mathematical models
can be developed.

REFERENCES
[1] Ioannides, M.G., “Design and implementation of PLC-based monitoring control system
for induction motor”, IEEE Transactions on Energy Conversion, Vol.19(3), 469-476, 2004
[2] Singh, Nandawar., “Design of a PLC system for fault monitoring using microcontrollers”,
AIJSER, Vol. 5(2), 230- 233, 2009
[3] Isermann, R., “Model-based Condition monitoring: Actuators, Drives, Machinery, plants,
sensors and fault tolerant systems”, Vol. XVI, 49-63, 2011
[4] Abhishek Sharma, V. Sugumaran, S. Babu Devasenapati, “Misfire Detection in an IC
engine using vibration signal and decision tree algorithm”, Measurement, Vol. 50, 370-380,
2014

AUTHOR’S BIOGRAPHY
Abhishek Sharma is a final year student in Bachelor of Technology (Electrical and
Electronics Engineering) at Vellore Institute of Technology, Chennai. His particular research
interests are in Control systems and application specific VLSI system design. He has also
published two international journal research papers and two IEEE conference papers (indexed
in IEEE Xplore). Currently he is pursuing his undergraduate thesis project at ABB India Ltd.,
Bangalore as an intern.

Project Report-Design of a PLC System for health monitoring of DC drive through SMS final

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