control of a pharmaceutical batch process

Karl Phelan Control of a Batch Process 27-04-2012

i

Control of a Pharmaceutical Batch Process

By

Karl Phelan

Project Document submitted to the Faculty of the

Institute of Technology, Blanchardstown

In partial fulfilment of the requirements for the degree of

Bachelor of Science

In

Sustainable Electrical & Control Technology

APPROVED:

_______________________ _______________________

David Peyton, Co-Advisor Gerard Duke, Co-Advisor

April 27th, 2012

Dublin, Ireland

Keywords: Batch Process, PLC, LabVIEW, VSD

Level Measurement, Temperature Measurement


ii

Declaration Page

Student Name: Karl Phelan

ID Number: B00036379

Course: Sustainable Electrical & Control Technology

Year: 3

Lecturer: Mr David Peyton/Gerard Duke

Title of Assignment: Final Project

Due Date: 27/04/2012

Date Submitted: 27/04/2012

I hereby certify that the material, which is submitted in this assignment/project, is entirely my

own work and has not been submitted for any academic assessment other than as part

fulfilment of the assessment procedures for the programme Bachelor of Science in

Sustainable Electrical & Control Technology(BN039). Any sources cited have been duly

acknowledged in the text.

Signed: ____________________________ Date: 27/04/2012


iii

1 Acknowledgements

I would like to express my deepest thanks to the lecturers of the BSc. Sustainable

Electrical & Control Technology course for their unfaltering support over the last 3

years. They have provided me invaluable knowledge required to undertake this

project.

In particular I would like to thank David Peyton and Gerard Duke for their hard work

and dedication in setting up this course as a whole. If it wasn’t for these two none of

this would be possible.

During the course of the previous semester Dave and Ger have provided help on

numerous occasions when I found myself languishing in a problem. Their patience

and understanding is a model for all.

Of the many lecturers on the faculty there are several who have provided a helping

hand whenever needed.

I would sincerely like to give thanks to John Kilcoyne and Owen Flood. They have

provided vital assistance in their respective fields of knowledge when required over

the course of the project. Without their help I wouldn’t have gotten this far in the

project.

I would also like to thank the lab technician Ciaran O’Brien for maintaining the

hardware with which we used to build the project.

I would like to thank my colleague Francis Gibson for his input and help on the

project. I believe we worked well as a team and I feel privileged to have been paired

with him during the project.

As a final word I would like to say I appreciate the opportunity to attend this course of

study. The Institute has provided me with a great opportunity to better myself both as

a professional and personal individual.


iv

2 Abstract

The following document comprises of the completed final year project for the control

of a batch process (pharmaceutical). The project was undertaken over a 12 week

period by student Karl Phelan who is enrolled in BSc. Sustainable Electrical &

Control Technology degree course in the Institute of Technology, Blanchardstown.

Compiled inside this document is the knowledge gained by the student over the

previous semester and years.

Discussed within is an overview of the project and what is required of the student as

outlined in the project specification document.

It was required by the student to create a control process for the pharmaceutical

development of two recipes in a vessel. A selector switch selects either of the two

recipes which must be controlled in a specific manner as outlined in the project

specification chapter.

There are several sections to this document which can be described as:

A literature review which comprises of an overall description of each

component used to complete the project.

A description of the project specification.

A control and monitoring strategy which describes in detail the specific

components used to build the project, the software used to build the process

and methods which were undertaken to put it all together.

There is a chapter of technical drawings which describe how each component

is physically connected.

The programming and monitoring methods are discussed in detail in later

chapters and provide an overview of what software was used and how

effectively it was utilised.

As a whole the document encompasses several weeks of hard work broken down

into a formatted product for ease of understanding for the reader.


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3 Contents

1 Acknowledgements ............................................................................................. iii

2 Abstract ............................................................................................................... iv

3 Contents .............................................................................................................. v

4 Acronyms .......................................................................................................... viii

5 List of Figures...................................................................................................... ix

6 Introduction ......................................................................................................... 1

7 Literature Review Introduction............................................................................. 3

7.1 Introduction ................................................................................................... 3

7.2 Variable Speed Drives .................................................................................. 5

7.2.1 Eurotherm 601 Series (HA464518) ........................................................ 5

7.3 Electrical Installation; Eurotherm 601 ............................................................ 8

7.3.1 Control and Power .................................................................................. 8

7.4 Operating Configuration ................................................................................ 9

7.5 Thermocouple Temperature Measurement and Calibration ........................ 11

7.6 Thermocouple Temperature Calibrations .................................................... 13

7.7 PLC (FX3G & FX2N -5A) ............................................................................ 15

7.8 Level Measurement using Pressure Methods ............................................. 16

7.9 Current/Voltage Calibrator........................................................................... 18

7.10 Octocoupler ............................................................................................. 18

8 Project Specification .......................................................................................... 19

8.1 Recipe 1: ..................................................................................................... 19

8.2 Recipe 2: ..................................................................................................... 19

8.3 Tasks .......................................................................................................... 21

9 Control and Monitoring Strategy........................................................................ 22

9.1 Introduction ................................................................................................. 22

9.2 The Process ................................................................................................ 23


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9.2.1 K Type Thermocouple .......................................................................... 23

9.2.2 Pressure Transmitter ............................................................................ 23

9.2.3 Mitsubishi FX3G & Programming Station ............................................. 24

9.2.4 Mitsubishi FX2n-5A ................................................................................ 25

9.2.5 Eurotherm Variable Speed Drive .......................................................... 26

9.2.6 National Instruments myDaq ................................................................ 28

9.2.7 Monitoring Station/ LabVIEW ................................................................ 29

9.2.8 Block Diagram of Process .................................................................... 30

9.3 Schedule of Inputs and Outputs .................................................................. 31

9.3.1 Mitsubishi FX3g PLC Inputs/Outputs .................................................... 31

9.3.2 Mitsubishi FX2n-5A Special Function Block Inputs/Outputs ................. 32

9.3.3 National Instruments My DAQ .............................................................. 33

9.3.4 Eurotherm Variable Speed Drive 601 ................................................... 33

9.3.5 Octo-Coupler ........................................................................................ 34

9.3.6 Calibrators ............................................................................................ 34

9.4 ISA 5.1 Process Drawings........................................................................... 35

9.4.1 Process Drawing .................................................................................. 35

9.4.2 PLC Wiring Diagram ............................................................................. 36

9.4.3 myDaq Card ......................................................................................... 37

9.4.4 Eurotherm Variable Speed Drive .......................................................... 38

10 PLC Programming Station .............................................................................. 39

10.1 Melsoft GX Developer .............................................................................. 39

10.2 Functions ................................................................................................. 39

10.3 Ladder Description ................................................................................... 41

11 LabVIEW Monitoring Station .......................................................................... 53

11.1 Introduction .............................................................................................. 53

11.2 Front Panel .............................................................................................. 54


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11.3 Block Diagram.......................................................................................... 55

11.3.1 Individual Function Description.......................................................... 56

12 Individual Review ........................................................................................... 59

12.1 Timetable ................................................................................................. 61

13 Bibliography .................................................................................................... 63


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4 Acronyms

AC – Alternating Current

DC – Direct Current

SELV – Separate Extra Low Voltage

PLC – Programmable Logic Controller

V – Voltage

A – Amps

mA – Milliamps

I/O – Inputs & Outputs

VSD – Variable Speed Drive

SCADA – Supervisory Control & Data Acquisition

DAQ – Data Acquisition


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5 List of Figures

Figure 1 Eurotherm 601(Stubby Lathe Usa, 2007) ..................................................... 6

Figure 2 601 Control Terminal Description (Stubby Lathe Usa, 2007) ....................... 7

Figure 3 Open Tank(Peyton, 2009) .......................................................................... 16

Figure 4 Voltage/Current Calibrator(RS-Online, 2012) ............................................. 18

Figure 5 Sample Octocoupler(Lakshmi Anand K, 2008) .......................................... 18

Figure 6(Peyton, 2009) ............................................................................................. 23

Figure 7 FX3G PLC(Mitsubishi, 2006) ...................................................................... 24

Figure 8 VSD Input Terminals(Stubby Lathe Usa, 2007) ......................................... 26

Figure 9c Parameter 13 Settings (Stubby Lathe Usa, 2007) .................................... 27

Figure 10 Special Funtion Block(Mitsubishi, 2008) .................................................. 32

Figure 11 myDAQ Terminals(National Instruments, 2010) ....................................... 33

Figure 12 ISA 5.1 Process Drawing ......................................................................... 35

Figure 13 PLC Wiring Diagram ................................................................................ 36

Figure 14 myDAQ Wiring Diagram ........................................................................... 37

Figure 15 Eurotherm Variable Speed Drive .............................................................. 38

Figure 16 Hold On Example ..................................................................................... 40

Figure 17 Ladder Line 0 ........................................................................................... 41

Figure 18 Ladder Line 19 ......................................................................................... 41




Figure 22 Ladder Line 105 ....................................................................................... 45












x






Figure 38 LabVIEW Front Panel .............................................................................. 54

Figure 39 LabVIEW Block Diagram .......................................................................... 55

Figure 40 LabVIEW Start/Stop Function .................................................................. 56

Figure 41 LabVIEW Motor Control ........................................................................... 56

Figure 42 LabVIEW Temperature & Level Control/Recipe Selection ....................... 56


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6 Introduction

The following document comprises of the final year project of student Karl Phelan,

B00036379. Karl is attending Year 3 of course BN039, Sustainable Electrical &

Control Technology. As part of semester 2, year 3 of the programme it is required

that students undertake a final project.

The assigned project for the module has been selected as “Control of a Batch

Process”.

A batch process is used to control the production of a product usually made from raw

materials, be it in liquid form or solid state, in manufacturing/process plants such as

those in the pharmaceutical industry.

The automation of a batch process provides a much more efficient and safe way to

deliver on production targets, quality assurance and reduce capital expenditure.

The context for which this project is being mimicked is, as said above, for controlling

a batch process in a pharmaceutical plant.

This document encompasses the main bulk of work put in by students Karl Phelan

and Francis Gibson over a period of roughly 12 weeks each Wednesday.

Contained within this document is a structured and detailed layout of each task

carried out to complete this project and also an in-depth look at the main

components and methods used to achieve the completed process.

The literature review will attempt to provide the reader with an overview of each

component, rather than a detailed and specific look at a particular component. An in-

depth review of each component will be provided in the Control & Monitoring

Strategy chapter.

A schedule of inputs and outputs for each component is provided along with several

drawings within this document ranging from ISA 5.1 specification drawings to simple

wiring diagrams. It is hoped that these graphical depictions will provide the user with


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a greater understanding of how the process has been linked together in order for the

process to work as one.

It is hoped that by writing this document the reader can easily understand the control

of this particular pharmaceutical process with ease and clarity.


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7 Literature Review Introduction

7.1 Introduction

The following chapter provides a general overview of the hardware and software

being used to construct this process.

This chapter will attempt to provide the reader with an overview of each component

and describe to the reader what role each component has when designing the

control of a batch process.

This chapter also comprises of the Final Year Project Plan of student Karl. Karl is

attending Year 3 of course BN039, Sustainable Electrical & Control technology. As

part of Semester 2 of the programme it is required that students undertake this

module.

Topics Covered in this literature review include:

Variable Speed Drives

o This topic will deal with what a VSD is and how it can benefit the

process. The specific type of speed drive applicable to this project will

also be discussed in brief.

Configuration of the 601 Series Speed Drive

o The Eurotherm 601 series speed drive is the particular drive to be used

for this project and in this chapter its configuration will be discussed.

Thermocouple Temperature Measurement and Calibration

o This sub chapter deals with thermocouples. What are thermocouples

and what uses they provide.

PLC’s (Specifically Mitsubishi FX3G and 2n-5A)

o Programmable Logic Controllers are the main component of most

processes as they instruct the other components what to do. In this

chapter the Mitsubishi FX3G and special function block FX2n-5A will

be briefly discussed.


4

Level Measurement using Pressure Methods

o Level measurement can be achieved using many different methods.

The pressure method is specific to this process and it will be briefly

discussed here.

Current/Voltage Calibrators

o Current/Voltage calibrators are to be used to simulate the 4-20mA

signal that would generally be supplied from both the pressure and

level field devices. In this chapter calibrators will be described and their

use expanded on.

Octocouplers

o Octocouplers provide the ability to switch between two different

voltages safely.


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7.2 Variable Speed Drives

Variable speed drives are used in industry to control the speed of an AC electric

motor. This is done by controlling the frequency at which electrical power is supplied

to the motor.

Variable speed drives are used for many reasons, most notably the ability to run at

pre-set speeds as selected by a technician or motor operator. This can be useful for

energy saving and process applications as the motor can be operated at less than

full speed. This can be achieved by manipulating parameters on the speed drive

control centre.(ABB, 2008)

7.2.1 Eurotherm 601 Series (HA464518)

The Eurotherm 601 Range Variable Speed Drive will be used in this project. The 601

range of frequency inverters has been designed for speed control of standard 3-

phase induction motors. This range of VSD covers motor power ratings from 0.37kW

to 2.2kW (Stubby Lathe Usa, 2007)

A useful feature of the 601 is the ability to program the parameters on the device

without the need for an external device.

A quick glance at the manual will provide the operator with the knowledge and

information required to program the speed drive to a required standard.

Most of the 601 range can operate from either a single phase two wire supply of 22

to 240 volts or on a 3 wire 380 to 460 volt supply at 50 or 60 Hertz.

An advanced microprocessor technology provides a pulse width modulation strategy

for quiet operation.

The control terminals on the 601 are SELV (separated extra low voltage).(Stubby

Lathe Usa, 2007)


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Figure 1 Eurotherm 601(Stubby Lathe Usa, 2007)

7.2.1.1 LED Display

There is an LED display built into the speed drive to provide the user with quick

access to programmable parameters.

7.2.1.2 Function Keys

The function keys are used to navigate around the main machine interface.

7.2.1.3 Instruction Pull-out Guide

This panel is where the user can see sufficient information on the basic operation of

the VSD.

The following information is shown:

Drive status

Decoded titles of parameters

Decoding of numbers assigned to each operating mode


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Functions of each control terminal.(shown below)

Figure 2 601 Control Terminal Description (Stubby Lathe Usa, 2007)


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7.3 Electrical Installation; Eurotherm 601

The Eurotherm 601 has been designed and built to comply with EC Directive

89/336/EEC on EMC.

The following wiring guidelines must be adhered to prevent interference with other

electrical equipment.

7.3.1 Control and Power

To wire the control terminals or the power terminals:

Remove the terminal cover

Insert a flat-bladed screwdriver (size 3.5 mm max.) inside the smallest hole.

Lever the screwdriver keeping it firmly pressed into the hole. The cage will

open.

Insert the stripped wire (5mm to 6mm/0.22in.) or wire crimp inside the cage

keeping the screwdriver in position.

Remove the screwdriver. Note the cage provides the correct force for a

secure connection.(Stubby Lathe Usa, 2007)


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7.4 Operating Configuration

It is possible to control the 601 in two ways:

Remote mode using the analogue and digital input and outputs on the control

terminal

Local mode using the keypad

On the LED display it is possible to adjust built in parameters to manipulate the drive

to specific needs. There are 15 parameters which can be set by the user.

The 601 comes pre-set with factory defaults which will suit many applications. As

mentioned above it is possible to change these parameters to meet specific needs

when designing a process.

The parameters relevant to this project are as follows:

P1 - Minimum Speed (Pre-set 1): This is the frequency at which the 601 will

run when zero set point is applied.(Unless clamped by P2) – Range is 0 to

240 Hz and default is 0Hz

P2 – Maximum Speed (Pre-set 4): This is the frequency at which the 601 will

run when max set point is applied – Range is 0 to 204 Hz and default is

50/60Hz

P3 - This is the ramp up time. The time taken to go from 0 to max speed.

Range from 0.1-999s. Default is 10 seconds.

P4 – This is the ramp down speed. The time taken to go from max speed to 0.

Range from 0.1-999s. Default is 10 seconds.

P8 – Jog Speed (Pre-set 2): The speed at which the 601 will run if control

terminal 9 is high. Range is 0 – 240 Hz. Default is 10Hz

P9 – Pre-set Speed 3. The speed at which the 601 will run when p13 = 2, CT

8 is low and CT 9 is high.

P13 – Set point select. Used for selecting a 4-20mA set point.

(Stubby Lathe Usa, 2007)


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The pre-set speeds allow the process designer to program the speed drive to run at

the required speeds. These will be discussed later in the report.

The ramp up and down speed provides a way to bring the motor to the required

speed at a quicker pace if needed.

Parameter 13 allows to operator to set the speed drive to run at its pre-set speeds

(setting 2) or to drive the motor by running through 0-10V or 4-20mA ranges by

selecting settings 0 and 1 respectively.


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7.5 Thermocouple Temperature Measurement and Calibration

A thermocouple is a device that is made up of two differing metal alloys. They both

produce a voltage which is proportional to a temperature difference.

Thermocouples are widely used in the control and automation industry for

temperature measurement. Thermocouples can provide a millivolt differential which

can then be converted into a temperature equivalent and vice versa.(Omega, 2010)

In this project a K –Type thermocouple is to be used to measure temperatures

ranging from 0-50 degrees Celsius and from 250-350 degrees Celsius. A

temperature transmitter will be used to simulate temperatures. Thermocouples are

very rugged and inexpensive and can operate over a wide temperature range. A

thermocouple is created whenever two dissimilar metals touch. The contact point of

these two metals produces a small open-circuit voltage as a function of temperature.

Each thermocouple type has a reference table with corresponding millivolt figures.

The corresponding voltages for a K-Type thermocouple are as follows:

50oC – 2.023 Millivolt

250oC – 10.153 Millivolt

350oC - 14.293 Millivolt

Several types of thermocouples are available; these thermocouples are designated

by capital letters that indicate their composition. A table is shown below: (National

Instruments, 2012)

Thermocouple

Type

Conductors – Positive Conductors – Negative

B Platinum – 30% Rhodium Platinum-6% rhodium

E Nickel chromium alloy Copper-nickel alloy

J Iron Copper-nickel alloy

K Nickel chromium alloy Nickel-aluminum alloy

N Nickel chromium silicon Nickel-silicon-magnesium


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alloy alloy

R Platinum-13% rhodium Platinum

S Platinum-10% rhodium Platinum

T Copper Copper-nickel alloy

(National Instruments, 2012)


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7.6 Thermocouple Temperature Calibrations

Temperature Calibration provides a means to identify any inaccuracies in the

thermocouple.

To calibrate the thermocouple, two methods of calibration are used.

Thermal Calibration

Electrical Calibration

Thermal calibration consists of heating or cooling the probe to various temperatures.

During this process the output voltage or resistance values are recorded and will be

compared to reference values. The calibration of the thermocouple should be carried

out while it is in use by comparing it to a nearby comparison thermocouple. If the

thermocouple is removed and placed in a calibration bath, the output integrated over

the length is not reproduced exactly.(Engineering Toolbox, 2010)

Electrical Calibration consists of using a simulator that represents the probe that is to

be connected to the transmitter. Resistance and millivolt sources can be used to

simulate RTD’s and thermocouples respectively. (Kuphaldt, 2009)


14

Errors that can be found during calibration are:

Span

Zero

Linearity

Hysteresis


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7.7 PLC (FX3G & FX2N -5A)

A PLC is an industrial, digital computer which can monitor the state of input switches

or sensors. It then uses that information to operate output switches and internal

relays. It does this by way of an internal software program such as Melsoft GX

developer.

PLC’s are used in many different applications and have endless uses for industrial

purposes. Some uses for PLC’s are:

Lift and Escalator Operation

Batch Processing

Traffic Lights

Power Distribution

PLC’s have the ability to read several types of programming code, most notably:

Ladder Programming

SFC Programming (Sequential Function Chart)

The programming code used for this program is ladder programming.

With the information written by the process designer the PLC can control the process

to a specific pattern.

In the case of this project the Mitsubishi FX3G will be used to drive the VSD and to

provide information and control function/testing function to LabVIEW.

A PLC, combined with a special function block, has the ability to read voltage and

current signals from field devices such as level or temperature transmitters. In order

to do this in this project the Mitsubishi FX2n-5A has been selected.

The FX2N-5A is a special function block which can be added to the FX3G. The

FX2N-5A can be used to acquire and transfer generated analogue signals. These

can then be converted into comparable digital signals. These signals are accessed

by the PLC using the “T0” and “FROM” functions.

The FX2N-5A has 4 analogue input channels and 1 analogue output channel.


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7.8 Level Measurement using Pressure Methods

Level measurement can be achieved through various methods, for example:

Pressure

Ultrasonic

Nuclear

Radar

Level measurement is a useful ability when dealing with a container or tank of any

sort. It allows the operator to see how much liquid, gas or solid substance is currently

inside the tank.

A differential pressure or hydrostatic transmitter can be used to measure the level in

the tank for this process because the tank being used is open to

atmosphere.(Peyton, 2011)

As the tank being used is an open tank the hydrostatic level measurement method

will be used to measure its level.

The specific gravity of the liquid being processed is set at 1.13.

The Upper Range Value is calculated by Height X Specific Gravity.

The height of the tank being used has been found to be 10 Meters.

Calculations for this specific project are as follows:

Figure 3 Open Tank(Peyton, 2009)


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Recipe 1: @50% Level

Temperature Transmitter = 12mA

URV= 5 X 1.13 = 5.65 mH2O

LRV = 0 X 1.13 = 0 mH2O

Recipe 2: @80% Level

Temperature Transmitter = 16.8mA

URV = 8 X 1.13 = 9.04 mH2O

LRV = 0 X 1.13 = 0 mH2O


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7.9 Current/Voltage Calibrator

A current/voltage calibrator is used to mimic a current or voltage signal which would

normally be generated by field devices such as the pressure transmitter or a

temperature transmitter. In the case of this project the simulator will be mimicking a

4-20mA signal from the devices mentioned previously.

Figure 4 Voltage/Current Calibrator(RS-Online, 2012)

7.10 Octocoupler

Ocotocouplers are used when the switching of voltages is required. They can be

used, for example, when connecting a low voltage device with a medium or high

voltage device.

They work by transferring an electrical signal or voltage from one part of a circuit to

the other whilst isolating each circuit from each other for safety.(Lakshmi Anand K,

2008)

Figure 5 Sample Octocoupler(Lakshmi Anand K, 2008)


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8 Project Specification

The project specification gives a brief but clear and concise layout of what is required

of the student when attempting to complete the project. The following information is

adapted in full from the project brief.

A PLC based strategy must be developed to control a batch process in a vessel in a

pharmaceutical plant. A selector switch selects either of two recipes which must be

controlled as laid out below:

8.1 Recipe 1:

When a green start pushbutton is pressed an agitator in the vessel is run at 10% of

its rated speed for 30 seconds and stopped. The inlet valve to the vessel then opens.

The vessel is filled with a product with a specific gravity of 1.13 to 50% of its level

range. The inlet valve closes and a heater in the vessel is switched on. When the

temperature of the product reaches 250°C the heater switches off. An agitator

switches on and runs at 50% of its maximum speed for 45 seconds at the end of

which it is switched off. A red pushbutton is used to stop the process at any time.

8.2 Recipe 2:

When a green pushbutton is pressed an agitator in the vessel is run at 10% of its

rated speed for 10 seconds and stopped. The inlet valve to the vessel then opens.

The vessel is filled with a product with a specific gravity of 1.13 to 80% of its level

range. The inlet valve closes and a heater in the vessel is switched on. When the

temperature of the product reaches 350°C the heater switches off. An agitator

switches on and runs at 65% of its maximum speed for 1 minute at the end of which

it is switched off. A red pushbutton is used to stop the process at any time.

If the temperature in the vessel drops to 50°C, operation of the recipes must be

disabled. A maintenance key-switch must be used to reset the recipe.

The level in the vessel is measured using a gauge pressure transmitter with a 4-20

mA output. The temperature in the vessel is measured using a K type thermocouple

connected to a temperature transmitter with a 4-20 mA output.

Operation of a selector switch switches the PLC to maintenance mode. This disables

the recipe control program and enables a signal from an external


20

maintenance/monitoring station to drive the agitator motor to any speed between 0

and 100% full speed.

A maintenance/monitoring station is required to enable display and recording of

system operating information and to allow system testing to be carried out. The

maintenance/monitoring station will be developed using National Instruments

LabVIEW software. The monitoring station should provide digital and analogue

representation of analogue variables. In maintenance mode the station should

provide a facility to drive the agitator motor through its full speed range for test

purposes.

Students will be expected to implement extra design and presentation elements and

advanced functions in their LabVIEW monitoring station. For example, the use of

maths functions, data logging/trending, alarm functions, file exporting etc. may be

incorporated to enhance the station.

The recipe control program will be implemented using a Mitsubishi FX3G PLC.

Speed control of the agitator motor will be achieved using a Eurotherm Variable

Speed Drive.


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8.3 Tasks

All discrete field devices to be wired, tested and commissioned as

appropriate.

Level transmitter to be configured and calibrated.

Temperature transmitter to be configured and calibrated.

Mitsubishi PLC to be configured and communications established with

programming software.

Variable speed drive to be wired, configured and tested.

Program to be written, annotated and tested offline to meet the required

specification.

Program to be implemented and correct operation confirmed.

LabVIEW maintenance/monitoring station to be developed, tested and

implemented.

All documentation to be completed. (See section 5)

A progress log to be maintained by each project team member and a weekly

progress report is to be jointly presented to the project supervisor.

A final formal presentation of the project report to be presented to project

supervisor(s) and examiners


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9 Control and Monitoring Strategy

9.1 Introduction

The control and monitoring strategy deals with the use of each component, all

hardware used and how each of these components fit together to implement the

batch control process.

In order for the project to work as a whole it was necessary to incorporate a large

number of components. All components used complement each other and rely on

each other to function. Not only were field/discrete devices and hardware used to

implement the process but also software. Software was used to program the

processes and to monitor and test the processes whilst running and whilst in

maintenance mode.

In this chapter several of these components and hardware devices will be discussed

and detailed in full. Drawings will be included to show how each component fits

together and a full schedule of each components’ inputs and outputs will be included.

Discussed within this chapter:

Programming Station

o Melsoft GX Developer

Monitoring Station

o National Instruments LabVIEW

Hardware

o Programmable Logic Controller

Mitsubishi FX3G

FX 2n-5A

o Variable Speed Drive

Eurotherm HA464518

o National Instruments myDaq

o ISO-Tech ILC421

o Octo-coupler MCT61133H

o K-Type Thermocouple

o Pressure Transmitter


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9.2 The Process

It can be seen from the brief what is required in this process. The brief describes a

pharmaceutical batch process.

An open tank of 10 meters in height was selected as an adequate size to house the

recipes. An inlet valve when opened allows the flow of ingredients into the tank.

Housed within the tank itself is an agitator which churns and mixes the ingredients to

the required consistency. The agitator is controlled from the manipulation of the

variable speed drive.

The tank is fitted with a heating element to raise the temperature to a specific degree

and also with a pressure transmitter to determine the level of the tank so as the

correct amount of liquid substance can be entered into the tank.

9.2.1 K Type Thermocouple

A K-Type thermocouple is used to determine the temperature within the tank at any

given time. It has a range of 0-1000oC which is more than adequate to fit its purpose

on this process. This is connected to a temperature transmitter and sent back to the

PLC and LabVIEW monitoring station through way of the National Instruments

myDaq signal acquirer and generator.

9.2.2 Pressure Transmitter

A pressure transmitter is used to measure the level through pressure methods. This

is also connected to the PLC and LabVIEW monitoring station.

Figure 6(Peyton, 2009)

The use of the pressure and temperature transmitters in conjunction with the process

program (PLC Ladder) and the numerous fail safes allow the safe and efficient

running of this process at all times.


24

9.2.3 Mitsubishi FX3G & Programming Station

The programmable logic controller used to drive the process was the Mitsubishi FX

3G PLC. The user generates a series of code to control the components which are

wired to the PLC. This code is known as a logic ladder.

The logic ladder for this project was written using the Melsoft GX Developer. The

ladder is basically a set of instructions which tell the PLC how to handle all the

components used in the process. Depending on how the ladder is written the user

can tell the PLC which outputs to switch on depending on which input has been

operated by the user. For example, a green push button to start the process.

Figure 7 FX3G PLC(Mitsubishi, 2006)

The PLC is the brain of the process. In this project the PLC controls every aspect of

the process from the starting of the process to controlling the variable speed drive to

receiving and sending analogue and digital signals through the special function

block. These commands are carried out through the several input and output

terminals on the PLC.

The use of the compare function was utilised when programming the level and

temperature commands. This allows the PLC to operate certain functions or outputs

when a required level or temperature has been reached.

“To” and “From” commands are used in the ladder program to instruct the PLC to

read and write the analogue signals coming to and from the pressure, temperature

transmitters and other components such as the myDaq and variable speed drive.


25

As required in the project specification the use of timer functions, internal relays and

indicator lamps also provide essential information in the PLC monitor mode and also

in the monitoring station to allow for efficient operation of the process.

There are seven input terminals and 5 output terminals on the FX3G PLC. This is

more than adequate for the operation of this batch process.

The PLC is electrically connected to several push buttons which allows for the

operation of several functions including:

Start

Stop

Recipe Selection

Maintenance Mode Selection

The output terminals on the PLC control several features in this process including,

but not limited to, the variable speed drive and indicator lamps.(Mitsubishi, 2009)

9.2.4 Mitsubishi FX2n-5A

The special function block being used in this project is the Mitsubishi FX 2n-5A.

The special function block is an additional piece of hardware which allows the PLC to

process analogue signals and utilise those signals for programming purposes. There

are 4 input terminals and 1 output terminal on the special function block.

For this process the signals being used allow the PLC to determine the level and

temperature being measured inside the process tank. With this knowledge the user

can write code to turn on or off the agitator or an indicator, for example, when the

liquid is at a specific level or temperature.

The special function block can be used for the utilisation of analogue signals, both

generated and acquired. For example, in this project analogue signals are used to

drive the motor through its full range of speed for maintenance purposes.

The special function block is connected electrically to the myDaq card for signal

processing and to the Eurotherm VSD for maintenance mode testing.(Mitsubishi,

2008)


26

9.2.5 Eurotherm Variable Speed Drive

The Eurotherm HA464518 was selected as a suitable speed drive. The speed drive

is mechanically connected to the agitator (motor) housed within the process tank.

Once a certain set of instruction are met within the PLC the variable speed drive will

begin to operate. Depending on what instructions have been fulfilled the variable

speed drive will operate at different speeds to meet the requirements of the process.

The VSD is electrically connected to the PLC, special function block and to neutral.

(For maintenance testing)

9.2.5.1 Speed Drive Settings

There are several parameter settings which can affect the operation of the VSD.

Parameter 13, for example, is used to control the speed of the motor. For this project

setting zero is selected when running maintenance mode whilst setting 2 allows the

PLC to instruct the motor to run at pre-set speeds which the user can define.

This image shows a schedule of inputs available on the speed drive and what each

terminal is used for.

For setting up speed control it is necessary to

access and manipulate several different

parameters on the speed drive. These

parameters control the pre-set speeds on the

speed drive. The images below show an

excerpt from the Eurotherm manual:

Figure 9a User Adjustable Parameters A(Stubby Lathe Usa, 2007)

Figure 8 VSD Input Terminals(Stubby Lathe Usa, 2007)


27

Figure 9b User Adjustable Parameters B(Stubby Lathe Usa, 2007)

In order for the speed drive to run on these pre-sets we must access parameter 13

and select setting 2.

As the motor runs at 50Hz max speed we can deduce that if we divide 50/100 it will

give us 1% of the motors overall speed (0.5 Hz).

The project specification asks for several speeds:

10%

50%

65%

Therefore we can calculate that 5Hz is the equivalent of 10% (0.5 x 10) etc. From the

manual we can then enter the correct hertz range in the required parameters.

Parameter 1 – 0Hz (0%)

Parameter 2 – 32.5Hz (65%)



In order for these pre-set speeds, in

parameter 13, to operate correctly it is

necessary to apply 24V and 0V in a specific

sequence.

This can be seen in this image. In setting 2 in order for pre-set speed 2 to run a 24V

signal must be applied to terminal 8 and a 0V signal applied to terminal 9.

The same applies to pre-set speed 4 except for this to operate a 24V signal must be

applied to both terminal 8 & 9 simultaneously.

Figure 9c Parameter 13 Settings (Stubby Lathe Usa, 2007)


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9.2.6 National Instruments myDaq

The myDaq card allows for the generation and acquiring of analogue and digital

signals to and from the PLC and variable speed drive when used in conjunction with

the monitoring station.

The monitoring station is used to view the status of the process whilst running or in

maintenance mode.

The myDaq is connected electrically to the pressure transmitter, temperature

transmitter and also to the special function block to allow the operation of

maintenance mode.

The myDaq has the ability to generate and acquire:

2 analogue outputs

2 analogue inputs

7 digital inputs/outputs

For this process all the analogue inputs, 1 analogue output and 4 digital outputs are

being utilised.

The analogue signals are used to read and write signals from the transmitters and to

the PLC etc. whilst the digital signals allow for the operation of the program through

the LabVIEW user interface rather than by the operation of push buttons and

selector switches.

The digital signals need to be sent through an octocoupler in order for the safe

operation of the process as the NI MyDaq is powered by a 5V DC supply whilst the

PLC is powered by a 24V DC supply.


29

9.2.7 Monitoring Station/ LabVIEW

National Instruments LabVIEW has been selected to provide a monitoring station

and to a lesser extent a control station for the process in question.

The monitoring station is a visual representation of the process and can provide real-

time information about the operation of the process. In essence the monitoring

station is a GUI (graphical user interface) for the process.

The level, temperature, start and stop, and recipe selection are among some of the

processes that are being monitored on this station.

These processes are monitored and controlled by utilising signals which the MyDaq

card is generating and receiving from the field devices.

An additional feature that was implemented into the monitoring station is the ability to

control the process.


30

9.2.8 Block Diagram of Process

The following block diagram shows a graphical representation of how each

component is physically connected to each other. It is only a simple representation

and should not be considered a wiring/schematic diagram.

As can be seen above, each component is interlinked through the main hub which is

the Mitsubishi PLC. Although mentioned previously, we can see from the block

diagram, it is blatantly obvious that the PLC is the main component and control

centre for the whole process.

GX Developer LabVIEW

Mitsubishi FX3G PLC

X1 X2 R1 R2

Mitsubishi FX2n-5A

TT PT V

S

D


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9.3 Schedule of Inputs and Outputs

The following list is a schedule of all the inputs and outputs of each component used

to assemble the batch control process.

Each component is laid out below with all terminals shown. The destination point for

each terminal is also shown. These connections form the basis for the batch process

as they allow the co-operation and communication of each component when

required.

9.3.1 Mitsubishi FX3g PLC Inputs/Outputs

Input Terminal Destination

X1 Card 1 - Terminal EC / Green PB

X2 Card 2 - Terminal EC / Red PB

X3 Spare

X4 Spare

X5 2 Way Selector Switch (Maintenance Switch)

X6 DAQ Card Digital I/O Port 2 (Recipe 1)

X7 DAQ Card Digital I/O (Recipe 2)

Output Terminal Destination

Y0 Port 8 on Eurotherm speed drive (Motor 10%)



Y3 Inlet Valve Light (Yellow Indicator)

Y4 Heater Light (Red Indicator)

Y5 Level Reached Light (Green Indicator)


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9.3.2 Mitsubishi FX2n-5A Special Function Block Inputs/Outputs

Input Terminal Destination

IN1 V+ Red lead on the current simulator for level

IN1 V- AI 0+ on myDAQ

IN1 I+ Link with IN1 V+

IN2 V+ Red lead on the current simulator for Temperature

IN2 V- AI 1+ on myDAQ

IN2 I+ Link with IN2 V+

IN3 V+ Link with DAQ Card AO 0

IN3 V- Link with DAQ Card AGND

IN3 I+ Spare

Figure 10 Special Funtion Block(Mitsubishi, 2008)

Output Terminal Destination

OUT V+ Port 2 on the Variable Speed Drive

OUT V- Port 3 on the Variable Speed Drive

OUT I+ Blank


33

9.3.3 National Instruments My DAQ

Terminals Destination

AO 0 IN3 V+ on the special function block 1

AO AGND IN3 V- on the special function block 1

AI 0+ IN1 V- on the special function block 1

AI 0- Negative lead on level transmitter

AI 1+ IN1 V+ on the special function block 1

AI 1- Negative Lead on Temperature Transmitter

DIO 0 Terminal A on the opto-coupler card 1




DIO DGND Terminal C on the opto-coupler card 1,2,3,4

Figure 11 myDAQ Terminals(National Instruments, 2010)

9.3.4 Eurotherm Variable Speed Drive 601

Terminals Destination

Port 1 Negative connect to 24 V DC supply

(Maintenance Mode)

Port 2 OUT V+ on the special function block 1

Port 3 OUT V- on the special function block 1

Port 4 Blank

Port 5 Blank

Port 6 Link with Port 7 (Ready Signal)

Port 7 Link with Port 6 (Ready Signal)

Port 8 Y0 on the PLC 9 (Motor 10%)


34

Port 9 Y1, Y2 on the PLC (Y1 - Motor 50%/ Y2 – Motor

65%)

Port 10 Blank

9.3.5 Octo-Coupler

Card 1 - Terminal AC-EC

X1

Card 2 - Terminal AC-EC

X2

Card 3 – Terminal AC-EC

X6

Card 4 – Terminal AC-EC

X7

Terminal C on AC

DGND on myDaq

Terminal E on EC

24V Supply

9.3.6 Calibrators

Calibrator 1 Red Lead

IN1 V+ on Special Function Block

Calibrator 1 Black Lead

AI 0- on NI myDAQ

Calibrator 2 Red Lead

IN2 V+ on Special Function Block

Calibrator 2 Black Lead

AI 1- on NI myDAQ


35

9.4 ISA 5.1 Process Drawings

9.4.1 Process Drawing

Figure 12 ISA 5.1 Process Drawing


36

9.4.2 PLC Wiring Diagram

Figure 13 PLC Wiring Diagram


37

9.4.3 myDaq Card

Figure 14 myDAQ Wiring Diagram


38

9.4.4 Eurotherm Variable Speed Drive

Figure 15 Eurotherm Variable Speed Drive


39

10 PLC Programming Station

10.1 Melsoft GX Developer

The Melsoft GX developer was used to build the program needed to run the process

to the required specification. The GX developer is a graphical user interface to allow

the process designer to input functions and rules that the PLC must follow.

10.2 Functions

To – The “to” command can be used to transfer data from a buffer in the PLC

to the special function block.

From – The “from” command is used to transfer data from the special function

block to the controller base unit.

CMP Function – This is the compare function. The compare function allows

us to compare two figures, such as a registry and a numeric figure. For

example, CMP D10 K50 M10. This logic is basically telling the PLC to

compare registry D10 with a figure 50 and store the result in M10.

Registry Function – The registry function is denoted by the letter D. For

example D10. The registry is used to save constants such as numerical

figures.

Divide – The divide function, DIV, is used to divide two functions or constants.

Inputs – Inputs are used to control outputs and other functions such as timers

and counters etc. X1, for example, is usually used as a start button for a

program.

Outputs – Outputs are triggered by inputs and other functions. Outputs can

be timers, internal relays, motor, or indicators etc.


40

Internal Relay – Internal Relays are used as internal memory and can be

used for switching or to store data. For example when used in conjunction

with a compare function it may read: CMP D10 K50 M10. This means that the

result of the comparison between D10 and K50 will be stored in M10. The

significance of M10 is that it is used as the first of 3 consecutive outputs which

are set depending on the result of the comparison.

o Device is on: Value greater than 10 (M10)

o Device is on: Value equal to 10 (M11)

o Device is on: Value less than 10 (M12)

Timer – T (Number) K (Number). An internal timer can be used to run outputs

and for switching relays etc. An example of a timer is as follows: T1 K 50.

This translates to Timer 1 running for 5 seconds.

Range – The set range, as per the manufacturer, for the PLC for input

devices are from 0-32000. For example and 4-20 mA calibrator will range at 0

when at 4mA and 32000 when at 20mA.

Hold On – A hold on is the equivalent of a latch. It will keep an output

switched on until the user or a user generated control tells the output to switch

off. The following is an example of a hold on. M4 is held on when M20 is true

as it is paralleled with M20.

Figure 16 Hold On Example


41

10.3 Ladder Description

Figure 17 Ladder Line 0

0 - The initial pulse M8002 sets up the PLC to read data on its first scan cycle only.

The “To” command is sending data from the data register K0 in the PLC to the

special function block 0. It specifies the input mode of channel 1 through 4. In this

ladder it is setting up the PLC to read current signals from channels 1, 2 and 4 and

read voltage signals from channel 3. K1 corresponds to the amount of data or, “bits”,

which the PLC should read. In this case K1 corresponds to 16 bits.

The second “To” function specifies the analogue output channels output mode. It

also specifies the input mode of channel 1 through 4. Although this function is setting

up the PLC to read current signals from channels 1, 2, 3 and 4. K1 corresponds to

the amount of data or, “bits”, which the PLC should read. K1 corresponds to 16 bits.



42

19 – The pulse M8000 is constantly reading data from the special function block to

the PLC. Line 19 shows the PLC reading the current value of channels 1 through 4

and stores that data in buffer address 6.

20 – Line 20 is a divide function and its objective is to take readings from D1, which

corresponds to channel 1 (Input 1) on the special function block.

A 4-20mA calibrator is connected to input 1. The current supplied by the

calibrator is converted to correspond to the 0-32000 range.

This is then divided by 320 and the result stored in data registry 10.

Data in registry 10 corresponds to a liquid level measured by a pressure

transmitter.

21 – Line 21 is also a divide function and corresponds to channel 2(Input 2) on the

special function block.

A 4-20mA calibrator is connected to input 2. The current supplied by the

calibrator is converted to correspond to the 0-32000 range.

This is then divided by 32 and stored in data registry 20.

Data registry 20 corresponds to the temperature read by a K-Type

thermocouple.


43


43 – M8000 tells the PLC to constantly read the data from the compare statements.

As seen previously the data for D1 (scaled) is being stored in D10. In line 43

we are comparing this data with a number, K50.

Should the scaled figure exceed 50; M10, an internal relay will be switched

on.

In line two; registry D10 is again used, this time for recipe 2. Should the data

in registry D10 exceed 80 then internal relay, M20, will be switched on.

Line 3 compares data from registry D20. It is compared with a figure of 250

which corresponds to a temperature limit. Should this be exceeded the

internal relay M30 will be switched on.

Line 4 again compares data in registry D20, this time with 350. Should this be

exceeded the internal relay M40 will be activated.

Line 5 allows for the addition of safety features further down the ladder to

provide an override for the process should the temperature drop below 50


44

Degrees. Data from registry 20 is compared with 50. Should this be exceeded

the relay M50 will be switched on.


79 – The constant pulse M8000 tells the PLC to constantly run the logic associated

with it through each scan cycle. The first line is telling the PLC to read data as a

voltage, through a 0-10V range, and store the data in buffer address 1 on the special

function block 0. K1 corresponds to the amount of data to be read in bits.

80 – The “To” command is taking data from the data register D3 on the PLC and is

transferring it to the buffer address 14 on the special function block K0. K1

corresponds to the amount of data that is to be read in bits.


98 – In order for the M1 relay to be switched on the following must be true:

The X6, recipe 1, selector switch must be selected

The X1 start button must be pressed

The normally closed stop button must be depressed

The maintenance switch must not be engaged

The recipe must not read below 50oC.(M8)


45


105 – In order for M2 to be switched on the following must be true:

X7, recipe 2, selector switch must be selected

X1, start button, must be pressed

X2, stop button, must be depressed

X5, maintenance switch must not be selected.

The recipe must not be below 50oC. (M8)


112 – M3 will be switched on if the level has reached 50% of its max level.

The data from M10, if on, will switch on the relay M3.



46

116 – M4 will be switched on if the level has reached 80% of its max level.

The data from M20, if on, will switch on the relay M4.

X2 must be depressed.


120 – The heater relay (Recipe 1), M5, will switch on if:

M30 has to be activated. The temperature must exceed 250oC.



124 – The heater relay (Recipe 2), M6, will switch on if:

M40 has to be activated. The temperature must exceed 350oC.



47


128 – Timer, T3, when activated will turn on relay M7


131 – The M8 relay is to turn on when the temperature falls below 50oC. Although

this can only be true when:

M3 is active

Or

M4 is active

And

The temperature must initially exceed 50oC.


48


136 – The output, Y1, drives the motor at 50% of its rated speed. In order for the

motor to run:

M5 must be on

M1 must be on

Timer, T3, must not be met.

Timer, T1, must be finished running.

The level must be at 50% (M3)

M7 must not be switched on.


143 – The motor Y0 will run when:

M1 run relay is switched on

Until T1 has been met.

M1 and T1 will not affect the motor Y2 as the timer T2 can only be activated

when recipe 2 is selected.

The M2 run relay can activate the motor Y0 while the timer T2 is running but

will stop when the timer has finished.


49

The Motor Y2 will run when:

M6 is activated

The M2 run relay has been switched on

The level has reached 80% on recipe 2 (M4)

The timer, T2, has completed

While T4 is running.


159 – The Valve Inlet will activate once:

Recipe 1:

T1 has been completed

The temperature, M30, is below 250oC

The level, M3, is below 50%

Recipe 2:

T2 has been completed

The temperature, M40, is below 350oC

The level, M4, is below 80%


50


169 – The heater Y4 will activate once:

Recipe 1:

The level, M10, has been reached

The temperature is below 250oC

M1, run relay, is activated

Timer, T1, has completed

X2 is depressed

Recipe 2:

The level, M20, has been reached

The temperature is below 350oC

M2, run relay, is activated

Timer, T2, has completed

X2 is depressed


182 – The level met indicator will switch on once:

Recipe 1:

The level, M10, has been met


51

Timer, T1, has been completed

Run relay, M1, is active

Recipe 2:

The level, M20, has been met

Timer, T2, has been completed

Run relay, M2, is active


190 – Timer 1 will run for 30 seconds once the M1 run relay is activated and whilst

X2 is depressed.


195 – Timer 2 will run for 10 seconds once the M2 run relay is activated and whilst

X2 is depressed.


200 – Timer 3 will run for 45 seconds once the heater temperature, M5, and the level

relay, M3, have been met. X2 must also be depressed.


52


206 – Timer 4 will run for 60 seconds once the heater temperature, M6, and the level

relay, M20, have been met. X2 must also be depressed.


53

11 LabVIEW Monitoring Station

11.1 Introduction

The National Instruments LabVIEW program was used to create a monitoring station

for this batch process. LabVIEW provides the user with a SCADA type graphical user

interface and monitoring station for controlling processes.

In regards to this project LabVIEW was used to provide a graphical interface and

monitoring station for the overall process. The project specification required that

LabVIEW be used to monitor and record system operating data and provide digital

and analogue representation of analogue variables such as the liquid level in the

tank and the temperature in the tank at any given time.

Addition requirements included the possibility of testing the variable speed drive

while the process was in maintenance mode. This would have to be achieved by

utilising analogue and digital signals in conjunction with the PLC and special function

block.

Extra functions have also been installed within the program to allow for a complete

control of the process from LabVIEW regardless of the discrete devices, i.e.

pushbuttons.

Data logging has been added to the program to allow for easy exporting of all data

collected during operation of the process.


54

11.2 Front Panel

The front panel allows the user to view operating information such as:

The level in the tank

The temperature of the liquid within the tank

A “level reached” indicator for both 50% and 80% levels on recipe 1 & 2

A “temperature reached” indicator for both recipe 1 & 2

A line chart for both level and temperature

o These can be exported to an excel document

Interactive buttons are available to the user to allow him/her to control the

process’ start and stop function without the need for using hardwired push

buttons

Recipe selection can also be controlled from the interface

For maintenance mode operation, as required in the project specification, it is

possible to test the agitator speed drive from 0% to 100% of its speed.

Figure 38 LabVIEW Front Panel


55

11.3 Block Diagram

Figure 39 LabVIEW Block Diagram

The block diagram is used to build to process’ general user interface, i.e. the front

panel. In the block diagram the necessary connections are made by the process

designer to allow the front panel to display the required information.

In the case of this project the DAQ Assistants are used to generate and acquire the

required signals from the myDAQ card. These can then be manipulated by way of

mathematical and visual functions to be displayed on the front panel.

The DAQ Assistants must be encased in a while loop in order for them to work.


56

11.3.1 Individual Function Description

This function is known as a DAQ Assistant. When

used in conjunction with the myDAQ card, it allows for

the control of the process’ start and stop function

directly from LabVIEW.

This function allows for the motor

to be tested whilst in

maintenance mode. This option

can only be used when the user

operates a maintenance switch.

The knob on the left provides the operator with a function to drive the motor through

its full range while the numerical indicator will relay what exact speed the motor is

running at. The knob has a range of 0-100.

Figure 40 LabVIEW Start/Stop Function

Figure 41 LabVIEW Motor Control

Figure 42 LabVIEW Temperature & Level Control/Recipe Selection


57

This figure is then divided by a numerical constant, 10, as the signal being generated

has a range of 0-10V. This is because industry generally uses a 0-10V range for

voltage signals and a 4-20mA signal for current signals. In this case we are

generating a 0-10V signal.

The divided numerical figure is then sent to the DAQ Assistant (myDAQ) to be

transferred to the special function block and ultimately the variable speed drive.

The figure above shows the Temperature & Level Control DAQ Assistant. This is the

process monitoring function to allow the user to view real-time temperature and liquid

level. It is interconnected with the recipe selection DAQ Assistant to allow the dual

use of level and temperature indicators. This is essentially an interlock so that certain

indicators will not illuminate for the wrong recipe. For example if recipe 1 is selected

only the 250oC and Level 50% indicators may operate as they are recipe 1

specification and vice versa.

Coming from the Temperature and Level DAQ Assistant we can see a multiplexer

and index array. These functions will separate the two signals being acquired within

the DAQ Assistant and allow the process designer to create a graphical display of

the acquired information.

There are two branches coming from the index array. As the current signals being

acquired are in the 4-20mA range both figures are multiplied by 1000 to convert each

numeric to usable digits.

At this point the constant numeric, 4, is subtracted from each figure to convert the

range from 4-20 to 0-16. This allows the lowest possible figure of 4 to be converted

to 0 on any graphical indicator, such as a tank.

This figure is then multiplied by a numerical constant, 6.25, for the level signal and

62.5 for the temperature signal. These figures will convert each respective signal into

a 0-100% range for level and 0-1000oC range for temperature.

For example if the signal acquired from the pressure transmitter on the tank is

15.4mA the following mathematical function will be carried out:

15.4mA x 1000= 15.4A

15.4A – 4= 11.4A


58

11.4A x 6.25= 71.25%

The tank indicator should read a liquid level of 71.25%.

The same principal applies to the temperature indicator.

For each respective signal the numerical result is then represented in a graphical

display.

Level is indicated in a tank display

Temperature is indicated in a thermometer display.

Located in the block diagram is also the ability to export data, for both level and

temperature, from a line graph. These can be exported to excel for further analysis.

The numerical constants on the right of the diagram 50, 80, 250, and 350 are

triggered by the respective numeric from the mathematical function discussed

previously. These work in conjunction with the recipe selection DAQ Assistant and

operate indicators on the front panel when the right requirements are met.


59

12 Individual Review

From the beginning, the project provided to myself and Francis Gibson, was a

challenge. We felt that at the time of selection we had received a project slightly on

the more difficult end of the scale. Nonetheless I believe we worked hard and tried

our best to fulfil the project specification and in the end I believe we succeeded in not

only meeting each requirement of the project specification but also exceeding the

project specification in some ways.

The physical side of the project was only available to us on a Wednesday for roughly

7 hours per week. Within that time we had to work on very challenging aspects of the

project implementation. Outside of that time we troubleshot the tougher aspects of

the project which we had trouble with.

Over the course of the project we ran into many troubling aspects and had to

overcome these in order to continue. One aspect that we found very troubling and

time consuming was resetting and rebuilding the project with the shared equipment

supplied by the Institute each week.

Although this was time consuming and sometimes caused problems to appear which

hadn’t on previous weeks I believe that it helped us to understand the physical build

and operation of the process in a more detailed manner which wouldn’t have

occurred otherwise.

I believe that working with the equipment each week brought a better understanding

of the project and helped to solidify the knowledge gained throughout the term.

We found whilst building the processes and physical equipment that some

troubleshooting solutions weren’t applicable to our situation which forced us to find

new ways to overcome the problems.

For instance we found that, to drive the motor in maintenance mode, we couldn’t use

a current signal and had to settle for a voltage signal. This problem took up a large

portion of one afternoon and caused many a headache.

It took several weeks but we quickly built the physical connections required of the

process. The hardest part of the project was the programming and monitoring


60

stations and adding the physical connections required to provide a monitoring station

for the process.

Designing a suitable ladder programme for the project was an on-going struggle as

each week we acquired new knowledge which would require us to alter certain

aspects of the ladder logic to fit the requirements.

Working with the special function block provided a challenge as the logic required us

to include new functions which we had not worked with previously in other modules.

I really found that the modules we took in previously years became useful tools for

problem solving, troubleshooting and as information sources to help in designing and

building the process.

I can see how they all led up to and helped provide the ability for myself, and for

each student, to complete this module in the best way possible.

The several PLC modules from previous semesters provided invaluable knowledge

when attempting to build the ladder logic required for this project. Whilst undertaking

those modules we spent a lot of time working with ladder building and also physically

wiring PLC’s. This helped me to better understand each aspect of the PLC.

Most modules provided useful knowledge when attempting this project yet several

standouts such as:

Computer Interfacing Technology

Process Measurement & Control

PLC’s 1 & 2

To a lesser extent, modules such as the following provided knowledge of

electrical/electronic components, motors and wiring etiquette.

Digital, Analogue & Industrial Electronics

Electrical Practice

Electrical Power & Machines


61

The Computer Interfacing Technology module was the sole module in which we

used LabVIEW. Whilst undertaking this module we completed several laboratory

exercises such as data acquisition which was a large part of the project.

During the Process Measurement & Control module we gained knowledge in the

methods of level measurement through pressure methods and also through

temperature measurement using thermocouples.

These modules provided me with the necessary tools to complete this project and

ultimately to put myself forward as a useful member of my team.

12.1 Timetable

In the beginning we started by setting up a project plan so as we could track our

progress and keep on schedule.

This was submitted in week two to the project supervisors for review.

We started out by looking at the variable speed drive and the user manual for the

Eurotherm 601 series. We researched how to set up the VSD to our required

specification through the different parameters and also how to physically connect the

VSD to each other component as required.

Soon after this we started to test several ladder program variations to gauge which

worked best for our project.

Keeping in line with the project plan we began attempting the acquisition of analogue

signals from the transmitters to the special function block.

We found great difficulty writing the logic for this and it took two weeks to get it right.

We spent a lot of time researching the manual for the FX2n-5A function block to

understand how to scale the signals and compare these signals to provide the

working functionality required by the project specification.

Once we had completed work on the VSD and PLC we attempted to focus on the

myDaq card and the monitoring station. We had trouble with the generation and

acquisition of signals at first yet overcame those with guidance from supervisors and

research.


62

In the final weeks we tidied and rearranged the logic ladder and monitoring station to

reflect a better and professional manner.

Compiling this project document allowed me to take a step back and have an overall

view on the whole project and how it all fit together in the end.

To conclude I really feel that the 3 years of knowledge greatly benefitted myself, and

all students, when attempting to complete this project.

In the end I feel I was given a great opportunity when given this project as I find

myself greatly interested in automation and process control after completing the

project and hope to continue in this stream of engineering.


63

13 Bibliography

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Engineering Toolbox, 2010. Thermocouples. [Online] Available at:

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2012].

Kuphaldt, T., 2009. Lessons in Industrial Instrumentation. PA Control.

Lakshmi Anand K, D.o.M.P.C., 2008. [Online] Available at:

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Mitsubishi, 2006. FX3G PLC. [Online] Available at: http://www.mitsubishi-

automation.com/products/compactplc_FX3G.html [Accessed April 2012].

Mitsubishi, 2008. FX2n-5A User Manual. [Online] Available at:

http://www.automationsystemsandcontrols.net.au/PDF's%20Mitsubishi/Manuals/FPL

C/FX2N-5A%20USER'S%20MANUAL.pdf [Accessed April 2012].

Mitsubishi, 2009. FX. [Online] Available at: https://my.mitsubishi-

automation.com/downloads/view/doc_loc/2340/166388.pdf?id=2340&saveAs=0&for

m_submit=View+now [Accessed April 2012].

National Instruments, 2010. Manuals. [Online] Available at:

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RTD. [Online] Available at: http://zone.ni.com/devzone/cda/tut/p/id/4252 [Accessed

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Omega, 2010. Thermocouples - An Introduction. [Online] Available at:

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http://www.abb.com/cawp/db0003db002698/a5bd0fc25708f141c12571f10040fd37.aspx

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http://www.mitsubishi-automation.com/products/compactplc_FX3G.html

http://www.automationsystemsandcontrols.net.au/PDF's%20Mitsubishi/Manuals/FPLC/FX2N-5A%20USER'S%20MANUAL.pdf

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http://www.ni.com/pdf/manuals/373060e.pdf

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Stubby Lathe Usa, 2007. Eurotherm 601 VFD Manual. [Online] Available at:

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control of a pharmaceutical batch process

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