Report on Design of Automatic Flame Sensor Testing

A VB based GUI for
Flame Optic Simulator
Anupam Das

A REPORT
ON

“A VB BASED GUI FOR FLAME OPTIC
SIMULATOR”

BY

Anupam Das
2006P8PS212
B.E. (Hons.) Electronics & Instrumentation

Prepared in Partial Fulfillment of the
Practice School – I Course No.
BITS C221/ BITS C231/ BITS C241

AT
Bharath Heavy Electricals Limited (BHEL), Tiruchirapalli

A Practice School – I Station of

BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE, PILANI
JULY, 2008
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ACKNOWLEDGEMENT
I would like to take this opportunity to express our heartfelt gratitude to all those
persons who have helped me to spend the most fruitful time in BHEL, Trichy in an
atmosphere of learning, wholesome knowledge and experience.

First and foremost we would like to thank the PS Division of BITS, Pilani for having
in faith in me and appointing me in such a wonderful PS-I Station. Next I would like
to thank our PS instructor Dr. P. Srinivasan for guiding me throughout my stay and
providing me with valuable inputs regarding the plant and its units when no other
BHEL personnel were ready to spare their valuable time for me in the face of the
infrastructural change taking place.

The complete project would have been a mere pipedream without the guidance, help
and support of my mentors Mr. A. Shanmugham, Senior Deputy General Manager,
Controls & Instrumentation (FB), and Mr. K. Karthikeyan, Deputy Manager, Controls
& Instrumentation (FB). They were instrumental in introducing me to the new aspect
of communicating with electronic devices and devising them to suit our goals.
Nevertheless their constant moral support was a boosting factor throughout.

Last but not the least; I would like to thank my friends who shared their knowledge
with me any time and anywhere. They were always eager to help me with any kind of
technical know – how relevant for my project. I would also like to thank all those
known and unknown hands whose unparallel contribution can never be forgotten.

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BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE
PILANI (RAJASTHAN)
Practice School Division

Station: Bharath Heavy Electricals Limited (BHEL) Centre: Tiruchirapalli

Duration: From 22nd May, 2008 To: 15th July, 2008

Date of Submission 14th July, 2008

Title of the Project: “A VB Based GUI for Flame Optic Simulator”

2006P8PS212 Anupam Das Electronics & Instrumentation

Name of expert: Mr. K. Karthikeyan Designation: Deputy Manager, C&I (FB)

Name of the PS Faculty: Dr. P. Srinivasan

Key Words: Flame, Optic, Simulator, RS-232, Serial Communication

Project Area: Controls & Instrumentation

Abstract: This project aims at developing an Integrated Visual Basic Application for
interfacing a light source, light filter, light chopper and flame scanner, to
simulate a real – time boiler furnace flame and, measure its intensity and
flicker frequency via the scanner thus establishing the genuinity of the
flame scanner as well. This is achieved by using serial communication
principles and data transmission based on RS – 232 standard.

Signature of Student Signature of PS Faculty

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Table of Contents
Chapter Chapter Page
No. No.
1 Introduction 8
2 Basics of Serial Communication Used in the 10
Project
2.1 What is Serial Communication? 10
2.2 The Serial Port Interface Standard 10
2.3 Connecting two devices with a Serial Cable 10
2.4 Serial Port Signals and Pin Assignments 11
2.5 Signal States 12
2.6 Data Pins 13
2.7 Control Pins 13
2.8 Serial Data Format 14
2.8.1 Byte Versus Values 15
2.8.2 Synchronous and Asynchronous Communication 15
2.8.3 How are the Bits Transmitted? 15
2.8.4 Start and Stop Bits 16
2.8.5 Data Bits 16
2.8.6 The Parity Bit 16
3 A Quick Peek into the Devices used for 18
Simulating the Flame
3.1 The Light Source 18
3.1.1 Collimated Beam 19
3.1.2 Real Lenses 19
3.1.3 Spherical Aberrations 19
3.1.4 Chromatic Aberrations 19
3.1.5 Important Parts of the Source 19
3.2 Light Filter (Model No. 74041) 21
3.3 Light Chopper (Model No. MC1000A) 22
3.3.1 Input/ Output Specifications 23
3.3.2 Controller Front Panel Features 24
3.3.3 Optical Head 26
4 Testing Procedure Involved 27

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5 Simulation & Validation 28
5.1 How do the above mentioned devices simulate a 28
real time boiler furnace flame?
5.2 Validating a Flame Scanner 29
6 Visual Basic Codes Involved 31
6.1 The MSComm Control of Visual Basic 31
6.2 “Welcome Page” 33
6.2.1 Code 33
6.3 “Details Page” 36
6.3.1 Code 36
6.4 “Test Page” 38
6.4.2 Code 38
7 Result 41
Bibliography 42

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Table of Figures & Tables
Figure Number Figure Details Page
Number
1 DTE to DCE Connection 11
2 Null Modem Connection 11
3 DB9 Pin Configuration 12
4 Data & Control Signal 13
5 Serial Data Format 14
6 The QTH Light Source 18
7 Details of Light Source 20
8 Light Filter 21
9 Light Chopper 22
10 Chopper Front Panel 24
11 Chopper Mounting 26
12 Flow of Light 28
13 MSComm Control 31
14 The Welcome Page 33
15 The Details Page 36
16 The Test Page 38

Table Table Details Page
Number Number
1 Serial Port Pin and Signal 12
Assignment
2 Parity Types 17
3 Filter wheel Characteristics 21
4 Data Table of Flame Scanner 29

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1. Introduction
The flame generated due to firing of the fuel through the burners, is required to be
monitored continuously to avoid accumulation of un-burnt fuel components in the
furnace (which may lead to explosion). Suitable flame scanners are employed to
monitor the flame.

In corner fired boiler furnaces, four flame scanners are installed at one level in the
four corners of the furnace. Each flame scanner consists of a scanner head with fiber
optic cable assembly. The scanner head housing contains an electronics module that
converts the light transmitted from the furnace flame via a fiber optic light guide, to an
electric current signal. The electric signal is further taken to a signal-processing
module. Input from each flame scanner is divided into 2 components viz. one
corresponding to intensity and the other corresponding to flicker frequency. Both
signals are processed digitally in micro controller based equipment to compute
intensity and flicker frequency parameters of the flame. The apparatus also has the
facility for digital settings, indications and processing of other associated state of
flame parameters. The apparatus also determines the required availability of the flame
in the respective corners of the furnace.

In the currently available flame detectors, flame sensing is implemented through two
characteristics namely intensity of the flame & flicker frequency of the flame.

In known flame scanner apparatus, several electronic modules are used to perform the
signal processing and logic control functions. One module receives the electric signal
from the light transducer (that views the flame) and transmits it for further signal
processing. The signal processing modules typically perform intensity comparison
check and flicker frequency comparison check for the flame signal with preset values
for ascertaining the presence/absence of flame in the field of view.

A need exists for an integrated testing system for the flame scanner apparatus. The
testing system will have to incorporate features to test the functionality of the flame
scanner apparatus in such a manner as to
a) Ascertain the functionality of the scanner more accurately than the legacy
systems.
b) Log the testing data for future reference & traceability.
c) In case of a faulty apparatus, to clearly identify the nature of the fault present.
d) Enunciate the nature of fault present for further corrective action.

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Other than the above-mentioned aspects, a need is felt for simplifying the testing
procedure and reducing the tie it takes to conduct the functional test of a flame
scanner apparatus.

The invented system for testing the flame scanner apparatus meets the above
mentioned needs in a manner most suitable for use with any type of known flame
scanner apparatus.

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2. Basics of Serial
Communication Used in the
Project
2.1 What Is Serial Communication?
Serial communication is the most common low-level protocol for communicating
between two or more devices. Normally, one device is a computer, while the other
device can be a modem, a printer, another computer, or a scientific instrument such as
an oscilloscope or a function generator. As the name suggests, the serial port sends
and receives bytes of information in a serial fashion - one bit at a time. These bytes are
transmitted using either a binary (numerical) format or a text format.

2.2 The Serial Port Interface Standard
The serial port interface for connecting two devices is specified by the TIA/EIA-232C
standard published by the Telecommunications Industry Association. The original
serial port interface standard was given by RS-232, which stands for Recommended
Standard number 232. The term "RS-232" is still in popular use, and is used in this
guide when referring to a serial communication port that follows the TIA/EIA-232
standard. RS-232 defines these serial port characteristics:
• The maximum bit transfer rate and cable length
• The names, electrical characteristics, and functions of signals
• The mechanical connections and pin assignments
Primary communication is accomplished using three pins: the Transmit Data pin, the
Receive Data pin, and the Ground pin. Other pins are available for data flow control,
but are not required. Other standards such as RS-485 define additional functionality
such as higher bit transfer rates, longer cable lengths, and connections to as many as
256 devices.

2.3 Connecting Two Devices with a Serial Cable
The RS-232 standard defines the two devices connected with a serial cable as the Data
Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE). This
terminology reflects the RS-232 origin as a standard for communication between a
computer terminal and a modem. Throughout this guide, your computer is considered
a DTE, while peripheral devices such as modems and printers are considered DCE's.

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Note that many scientific instruments function as DTE's. Because RS-232 mainly
involves connecting a DTE to a DCE, the pin assignments are defined such that
straight-through cabling is used, where pin 1 is connected to pin 1, pin 2 is connected
to pin 2, and so on. A DTE to DCE serial connection using the transmit data (TD) pin
and the receive data (RD) pin is shown below.

Figure 1 DTE to DCE Connection

If you connect two DTE's or two DCE's using a straight serial cable, then the TD pin
on each device are connected to each other, and the RD pin on each device are
connected to each other. Therefore, to connect two like devices, you must use a null
modem cable. As shown below, null modem cables cross the transmit and receive
lines in the cable.

Figure 2 Null Modem Function

2.4 Serial Port Signals and Pin Assignments
Serial ports consist of two signal types: data signals and control signals. To support
these signal types, as well as the signal ground, the RS-232 standard defines a 25-pin
connection. However, most PC's and UNIX platforms use a 9-pin connection. In fact,
only three pins are required for serial port communications: one for receiving data,
one for transmitting data, and one for the signal ground. The pin assignment scheme
for a 9-pin male connector on a DTE is given below.

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Figure 3 DB9 Pin Configuration

The pins and signals associated with the 9-pin connector are described below.

Pin Label Signal Name Signal Type
1 CD Carrier Detect Control
2 RD Receive Data Data
3 TD Transmit Data Data
4 DTR Data Terminal Ready Control
5 GND Signal Ground Ground
6 DSR Data Set Ready Control
7 RTS Request To Send Control
8 CTS Clear To Send Control
9 RI Ring Indicator Control

Table 1 Serial Port Pin and Signal Assignments

The term "data set" is synonymous with "modem" or "device," while the term "data
terminal" is synonymous with "computer."

2.5 Signal States
Signals can be in either an active state or an inactive state. An active state corresponds
to the binary value 1, while an inactive state corresponds to the binary value 0. An
active signal state is often described as logic 1, on, true, or a mark. An inactive signal
state is often described as logic 0, off, false, or a space. For data signals, the "on" state
occurs when the received signal voltage is more negative than -3 volts, while the "off"
state occurs for voltages more positive than 3 volts. For control signals, the "on" state
occurs when the received signal voltage is more positive than 3 volts, while the "off"
state occurs for voltages more negative than -3 volts. The voltage between -3 volts and
+3 volts is considered a transition region, and the signal state is undefined. To bring
the signal to the "on" state, the controlling device un-asserts (or lowers) the value for
data pins and asserts (or raises) the value for control pins. Conversely, to bring the
signal to the "off" state, the controlling device asserts the value for data pins and un-
asserts the value for control pins. The "on" and "off" states for a data signal and for a
control signal are shown below.

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Figure 4 Data & Control Signal

2.6 Data Pins
Most serial port devices support full-duplex communication meaning that they can
send and receive data at the same time. Therefore, separate pins are used for
transmitting and receiving data. For these devices, the TD, RD, and GND pins are
used. However, some types of serial port devices support only one-way or half-duplex
communications. For these devices, only the TD and GND pins are used. In this guide,
it is assumed that a full-duplex serial port is connected to your device. The TD pin
carries data transmitted by a DTE to a DCE. The RD pin carries data that is received
by a DTE from a DCE.

2.7 Control Pins
9-pin serial ports provide several control pins that:
• Signal the presence of connected devices
• Control the flow of data
The control pins include RTS and CTS, DTR and DSR, CD, and RI.
The RTS and CTS Pins. The RTS and CTS pins are used to signal whether the
devices are ready to send or receive data. This type of data flow control - called
hardware handshaking - is used to prevent data loss during transmission. When
enabled for both the DTE and DCE, hardware handshaking using RTS and CTS
follows these steps:
• The DTE asserts the RTS pin to instruct the DCE that it is ready to receive data.
• The DCE asserts the CTS pin indicating that it is clear to send data over the TD
pin. If data can no longer be sent, the CTS pin is unasserted.
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• The data is transmitted to the DTE over the TD pin. If data can no longer be
accepted, the RTS pin is unasserted by the DTE and the data transmission is
stopped.

The DTR and DSR Pins. Many devices use the DSR and DTR pins to signal if they
are connected and powered. Signaling the presence of connected devices using DTR
and DSR follows these steps:
• The DTE asserts the DTR pin to request that the DCE connect to the
communication line.
• The DCE asserts the DSR pin to indicate it's connected.
• DCE un-asserts the DSR pin when it's disconnected from the communication
line.
The DTR and DSR pins were originally designed to provide an alternative method of
hardware handshaking. However, the RTS and CTS pins are usually used in this way,
and not the DSR and DTR pins. However, you should refer to your device
documentation to determine its specific pin behavior.

The CD and RI Pins. The CD and RI pins are typically used to indicate the presence
of certain signals during modem-modem connections. CD is used by a modem to
signal that it has made a connection with another modem, or has detected a carrier
tone. CD is asserted when the DCE is receiving a signal of a suitable frequency. CD is
unasserted if the DCE is not receiving a suitable signal. RI is used to indicate the
presence of an audible ringing signal. RI is asserted when the DCE is receiving a
ringing signal. RI is unasserted when the DCE is not receiving a ringing signal (for
example, it's between rings).

2.8 Serial Data Format
The serial data format includes one start bit, between five and eight data bits, and one
stop bit. A parity bit and an additional stop bit might be included in the format as well.
The diagram below illustrates the serial data format.

Figure 5 Serial Data Format

The format for serial port data is often expressed using the following notation
“number of data bits - parity type - number of stop bits”. For example, “8-N-1” is
interpreted as eight data bits, no parity bit, and one stop bit, while 7-E-2 is interpreted
as seven data bits, even parity, and two stop bits. The data bits are often referred to as

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a character because these bits usually represent an ASCII character. The remaining
bits are called framing bits because they frame the data bits.

2.8.1 Bytes versus Values
The collection of bits that comprise the serial data format is called a byte. At first, this
term might seem inaccurate because a byte is 8 bits and the serial data format can
range between 7 bits and 12 bits. However, when serial data is stored on your
computer, the framing bits are stripped away, and only the data bits are retained.
Moreover, eight data bits are always used regardless of the number of data bits
specified for transmission, with the unused bits assigned a value of 0. When reading or
writing data you might need to specify a value, which can consist of one or more
bytes. For example, if you read one value from a device using the int32 format, then
that value consists of four bytes.

2.8.2 Synchronous and Asynchronous Communication
The RS-232 standard supports two types of communication protocols: synchronous
and asynchronous. Using the synchronous protocol, all transmitted bits are
synchronized to a common clock signal. The two devices initially synchronize
themselves to each other, and then continually send characters to stay synchronized.
Even when actual data is not really being sent, a constant flow of bits allows each
device to know where the other is at any given time. That is, each bit that is sent is
either actual data or an idle character. Synchronous communications allows faster data
transfer rates than asynchronous methods, because additional bits to mark the
beginning and end of each data byte are not required. Using the asynchronous
protocol, each device uses its own internal clock resulting in bytes that are transferred
at arbitrary times. So, instead of using time as a way to synchronize the bits, the data
format is used. In particular, the data transmission is synchronized using the start bit
of the word, while one or more stop bits indicate the end of the word. The requirement
to send these additional bits causes asynchronous communications to be slightly
slower than synchronous. However, it has the advantage that the processor does not
have to deal with the additional idle characters. Most serial ports operate
asynchronously.

2.8.3 How Are the Bits Transmitted?
By definition, serial data is transmitted one bit at a time. The order in which the bits
are transmitted is given below:
• The start bit is transmitted with a value of 0.

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• The data bits are transmitted. The first data bit corresponds to the least
significant bit (LSB), while the last data bit corresponds to the most significant
bit (MSB).
• The parity bit (if defined) is transmitted. One or two stop bits are transmitted,
each with a value of 1.
The number of bits transferred per second is given by the baud rate. The transferred
bits include the start bit, the data bits, the parity bit (if defined), and the stop bits.

2.8.4 Start and Stop Bits
As described in Synchronous and Asynchronous Communication, most serial ports
operate asynchronously. This means that the transmitted byte must be identified by
start and stop bits. The start bit indicates when the data byte is about to begin and the
stop bit(s) indicates when the data byte has been transferred. The process of
identifying bytes with the serial data format follows these steps:
• When a serial port pin is idle (not transmitting data), then it is in an "on" state.
• When data is about to be transmitted, the serial port pin switches to an "off"
state due to the start bit.
• The serial port pin switches back to an "on" state due to the stop bit(s). This
indicates the end of the byte.

2.8.5 Data Bits
The data bits transferred through a serial port might represent device commands,
sensor readings, error messages, and so on. The data can be transferred as either
binary data or ASCII data. Most serial ports use between five and eight data bits.
Binary data is typically transmitted as eight bits. Text-based data is transmitted as
either seven bits or eight bits. If the data is based on the ASCII character set, then a
minimum of seven bits is required because there are 27 or 128 distinct characters. If
an eighth bit is used, it must have a value of 0. If the data is based on the extended
ASCII character set, then eight bits must be used because there are 28 or 256 distinct
characters.

2.8.6 The Parity Bit
The parity bit provides simple error (parity) checking for the transmitted data. The
types of parity checking are given below.

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Parity Type Description
Even The data bits plus the parity bit result in an even number of 1's.
Mark The parity bit is always 1.
Odd The data bits plus the parity bit result in an odd number of 1's.
Space The parity bit is always 0.
Table 2 Parity Types

Mark and space parity checking are seldom used because they offer minimal error
detection. You might choose to not use parity checking at all. The parity checking
process follows these steps:
• The transmitting device sets the parity bit to 0 or to 1 depending on the data bit
values and the type of parity checking selected.
• The receiving device checks if the parity bit is consistent with the transmitted
data. If it is, then the data bits are accepted. If it is not, then an error is returned.
For example, suppose the data bits 01110001 are transmitted to your computer. If
even parity is selected, then the parity bit is set to 0 by the transmitting device to
produce an even number of 1's. If odd parity is selected, then the parity bit is set to 1
by the transmitting device to produce an odd number of 1's.

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3. A Quick Peek into the
Devices Used for Simulating
the Flame
3.1 The Light Source

Figure 6 The QTH Light Source

These lamps were designed for efficient production of light by the usage of 300 W
Quartz – Tungsten Filament Bulb and set of special lenses. The lenses are designed
for efficient collection of light from the filament. By moving the focusing lever, we
can move the position of the condenser lenses to produce a diverging beam,
“collimated beam” or to re-image the filament. The lenses in these housing are
designed for collimation rather than imaging. The lens shape and orientation are
selected to minimize lens induced distortion (aberration) when the lenses are close to
the position which produces a collimated beam (the collimating position). When you
use them for imaging, there are 2 penalties
• Lens aberrations increases
• Light collection is reduced
For imaging, the lens is moved further from the filament and so gathers less of the
light emitted by filament within its aperture. The lens operates at a high F/#.

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If we need to image the filament close to the lamp housing, or equivalently, produce a
small image of the filament, then it is more efficient to use the condenser in the
collimating position and use a secondary focusing lens to create the image.

3.1.1 Collimated Beam
The usual concept of a collimated beam is a parallel cylinder of light. If the intensity
is same anywhere across a section of the cylinder, the beam is uniform. Some residual
divergence in the limit governed by the laws of diffraction and they usually have non
– uniform, though sometimes known, intensity distributions.

3.1.2 Real Lenses
The condenser lenses are intended for efficient light collection from the filament.
They operate at low F/#S. As a result, the single element F/0.85 & F/1 lenses suffer
from severe spherical aberrations. All lenses perform best while collimating the light
from the source.

3.1.3 Spherical Aberrations
Light rays at the ends of a lens converge. This is called Spherical Aberration. In
general, spherical aberration is decreased by dividing the refraction as equally as
possible between as many surfaces as possible.

3.1.4 Chromatic Aberration
This term describes the variation of focal length with colour. This variation is due to
the change in the lens index of refraction (n) with wavelength. As the wavelength
increases, lens index decreases & focal length increases.

3.1.5 Important Parts of the Source
• Lamp and Reflector Adjustments
• Lamp cooling (Built – in – fan)
• Safety & monitoring features
• Elapsed Time Indicator (ETI) – 6 digit LCD Meter
• Mounting screws
• Housings with condensing lens

Note: For lamps running at 50 W or less, fan is not required.

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Figure 7 Details of Light Source

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3.2 Light Filter (Model No. 74041)

Figure 8 Light Filter

It is also known as the Light Intensity Variation device. It is a six position motorized
filter wheel system. The wheel holds upto six 1.0 inch (2.54 cms) diameter
filters/other optical components. The filter wheel can be remotely controlled, by a PC
using either IEEE – 488 (GPIB) or RS – 232 interfaces, or manually, via control box
front panel. The six filters available are:

Filter Wheel No. Kind of Light Transmitted
1 (Opaque)
2 UV Light
3 IR Light
4 20% Visible Light
5 60% Visible Light
6 80% Visible Light
Table 3 Filter Wheel Characteristics

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3.3 Light Chopper (Model No. MC1000A)

Figure 9 Light Chopper

It is also known as the Light Frequency Variation device. The MC1000A Optical
Chopper is a precision instrument utilizing advanced features to meet the most
demanding approach. The MC1000A uses a phased – lock loop (PLL) motor speed
control design to precisely lock the chopping speed and phase to a reference signal.
An internal, crystal stabilized frequency synthesizer provides an accurate and stable
reference frequency for ultra – low long term frequency drift.

Unlike conventional, open-loop speed control designs, the PLL speed control circuit
also allows the MC1000A chopper to be synchronized to external reference signals,
including other MC1000A choppers and reference sources such as DSP lock-in
amplifiers.

For more advanced measurements, the MC1000A can lock to a harmonic, sub –
harmonic, or fractional – harmonic of an external reference frequency. A second PLL
circuit is used to multiply the external reference up to the 15th harmonic. This
multiplier is followed by a digital divider to divide the reference down to the 15th sub
– harmonic. By combining both the frequency multiplication and division together, a
fractional harmonic can be obtained.

The MC1000A also supports 2-frequency chopping from a single chopper blade. A
special blade is available with 7 outer slots and 5 inner slots. This slot combination
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allows a single beam to be split and individually modulated for ratio metric
experiments. Other applications include pump-probe experiments where the pump
beam is modulated at the outer frequency while modulating a probe beam at the inner
frequency. The MC1000A provides the sum and difference frequencies of the 2-
frequency blade for accurate lock-in detection of the frequency-mixed response.

A high quality, Swiss-made, rare earth magnet DC motor and a photo-etched chopper
optical wheel drive the precision. The compact optical head has a wide base for extra
stability. The base is slotted for two ¼-20 mounting screws on 2” centers. The
interface cable uses standard RJ-45 modular connectors for easy setup.

The MC1000A controller includes a large, 4-digit, easy to read LED display for
monitoring the chopper frequency. All of the operating modes are accessible from
streamlined, front panel push-button controls. Multiple user setups can be easily saved
and recalled from non-volatile memory. An RS-232 serial interface is included as a
standard feature for remote interfacing the MC1000A to other equipment.

3.3.1Input/Output Specifications
• Ext. Input Compatibility: TTL/CMOS
• Ext. Input Voltage Range: 0 – 5V
• Input High > 2V
• Input Low <0.8V
• Ext. Input Impedance: 200Ω
• Ref Out Compatibility: TTL/CMOS
• Ref Out Voltage Range: 0 – 5V typ.
• Ref Out Impedance: 200Ω
• Min Load Impedance: 500Ω
• Ref Out Signals: Chopping Blade, Synthesizer, Sum and Diff Frequencies
• Ref Out Selection: ‘Mode’ Keypad selection or RS232 command ‘O’

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3.3.2 Controller Front Panel Features

Figure 10 Chopper Front Panel

1) FREQ DOWN / ENTER Key - This key is used to decrease the chopping
frequency when operating in the internal reference mode. It is also used for as
an enter key when setting the various operating parameters.
2) 4-Digit LED Display (to display operating frequency and user messages)
3) EXT IN ENABLE Key - Pressing this key toggles the MC1000 between the
internal and external reference mode.
4) EXT IN LED – This LED will illuminate when the External Input is enabled.
5) EXT REF IN - the external reference signal is connected to this input BNC
(TTL / CMOS logic level).
6) REF OUTPUT - the reference output signal selected by the REF SELECT
mode (CMOS logic level).
7) SAVE SETUP - When this LED is lit, the user can save the current
configuration to one of five setups. Use the FREQ UP / CYCLE key to select
the setup number and press the FREQ DOWN / ENTER to save the setup to
that number. Note: the setup number will wrap around back to 1 after it reaches
5 when pressing the FREQ UP / CYCLE key.
8) RECALL SETUP - In this mode, the user can recall one of the five user
setups. Select the setup number with the FREQ UP / CYCLE key and press the
FREQ DOWN / ENTER to restore the saved configuration.
9) SET D - This mode allows the user to select a sub-harmonic of the external
reference input. The external reference frequency will be divided by this value
and used to synchronize the chopper blade. The sub-harmonic can be used with

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the harmonic multiplier, N, to create fractional harmonics (i.e. chopper
frequency, fchopper = REFEXT * N / D).
Note: The Harmonic, N, and sub-harmonic, D, are only available when using
the external reference input and a single frequency chopping blade (i.e. 10, 15,
or 30 slot blade).
10) SET N - This mode allows the user to select a harmonic of the external
reference input. The external reference frequency will be multiplied by this
value and used to synchronize the chopper blade. The harmonic multiplier can
be used with the sub-harmonic divider, D, to create fractional harmonics (i.e.
chopper frequency, fchopper = REFEXT * N / D).
11) REF SELECT - This LED indicates the REF OUT signal mode. Pressing the
‘▲’ or ‘▼’ keys selects the ‘REF OUTPUT” signal from a number of sources
depending on the operating mode selected.

Operating Mode Available sync sources
Internal Reference Mode: OUT, SYN
External Reference: OUT
2-Frequency Blade: OUT, SYN, SUM, DIFF
Where: OUT = chopper wheel frequency (for the 2-frequency blade, the outer blade
frequency)
SYN = the internal frequency synthesizer (or the harmonic generator for the external
mode)
SUM = sum frequency for the 2 frequency blade
DIFF = difference frequency for the 2 frequency blade

12) MODE - Pressing this key cycles through the various input modes (REF
SELECT, SET N, SET D, RECALL and SAVE). The LED above the legend
indicates the currently active mode. Note: the available input modes are
dependent on the operating state (i.e. the SET N and SET D are not active when
operating in the internal reference mode).
13) POWER button - Press in to power the MC1000 on.
14) FREQ UP / CYCLE Key - This key is used to increase the chopping
frequency when operating in the internal reference mode. It is also used for
cycling through input options for other operating modes.

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3.3.3 Optical Head

Figure 11 Chopper Mounting

1) Precision Chopper Blade (available in 2,10, 15, 30 or 60 slots, and a 7:5 2-
frequency)
2) 1/16” Hex Mounting Screws and lock washers (qty 3)
3) Photo-interrupter Speed Sensor
4) Blade Hub
5) Modular Interface Connector
6) Mounting Base

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4. Testing Procedure Involved
The complete aim of the project was to incorporate the following test steps in the
Visual Basic based Graphical User Interface (GUI).
• Step – I: Initialize the Scanner Test Program
• Step – II: Fit the Scanner head on the test-mount , Connect the RS232 terminals
to PC
• Step – III: Note the project name & scanner code in the PC
• Step – IV: Select type of test configuration in the selection window as follows
a) Filter wheel Window
1) UV Filter
2) IR Filter
3) 60% Visible Filter
4) 80% Visible Filter
5) 20 % Visible Filter
b) Select flicker wheel frequency on the RPM controller display between 20
Hz – 1000 Hz.
• Step – V: Click ‘Test start’ after selecting test configuration
• Step – VI: The source controller turns ON the illuminating lamp source
• Step – VII: The filter controller turns the intensity filter to the set value
• Step – IX: The flicker controller runs the flicker wheel to the set frequency
• Step – X: After two minutes acknowledge the ‘Test complete’ message in PC
• Step – XI: Repeat the procedure from step 2 if any other scanners are required
to be tested.
• Step – XII: After the end of testing all the scanners, click “print report” for
printing the report of scanner test performed.

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5. Simulation & Validation
5.1 How do the above mentioned devices simulate a real
time boiler furnace flame?
The complete operation of these devices can be easily understood by the following
flow diagram of light:

Figure 12 Flow of Light

The light emanating from the filament of the Light Source comprises of various kinds
of light, like UV, IR, and Visible Light etc. This is similar to a furnace flame as a
flame in a furnace would have IR light emanated from the red – hot charred coal,
visible light from the flame being produced out of it and UV light too along with the
visible light.

This light is allowed to pass through a sequence of light filters in the motorized filter
wheel system which allows only a particular kind of light to pass through them at a
time. Thus we can isolate the various “intensities” of light from the mixture of light
falling on the filter wheel.

The boiler flame has a characteristic feature known as the “Flicker Frequency” which
is nothing but the vibrating effect of the flames. This frequency of vibration varies
according to the portion of the flame being monitored. The portion of the flame near
the coal has least flicker frequency whereas high above it has very high flicker

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frequency. This effect is introduced in the light coming from the filter using the Light
Chopper which chops the light in several planes according to the frequency set by the
user thus mimicking the flicker of the real – time boiler furnace flame.

The light coming out of the Light Chopper is a complete imitation of the boiler
furnace flame. This simulated light is allowed to fall on to the flame scanner.

5.2 Validating a Flame Scanner
The flame scanner is an assembly of flame sensor, fiber optic cable to transmit the
light signal to a transducer which converts it into an electric signal. The signal is sent
to a signal processing module which processes the intensity and the flicker frequency
of the light and sends back the control panel with a set of data. This data is generally
in the form of bytes of information. 2 bytes of data comprise of a particular kind of
information which is sent to a designated area in the memory (Registers with
particular address sequence). This data sequence is as follows:

Address Contents
40001 Intensity Corner 1
40002 Pull in Corner 1
40003 Pull Out Corner1
40004 Flicker Coal Corner 1
40005 Flicker Oil S1 Corner1
40006 Actual Freq1 Corner1
40008 Coal Flame Corner1
40009 Oil Flame Corner1

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40037 System Fault
40038 Flame On
40039 Slave Packet Count
40040 Firmware Version Numbers

Table 4 Data Table of Flame Scanner

If the flame intensity and flicker frequency sensed by the flame scanner matches with
the ones set by the user during simulation, then the scanner is said to be in “perfect
working condition”.

Page 30 of 42

6. Visual Basic Codes Involved
The complete application involves the following steps:
• The welcome page which introduces the user to the testing sequence.
• The welcome page allows the user to understand the procedure as directed and
also allows him to know the specific connections that have to be made before
starting the test procedure.
• The details page, which follows the welcome page, asks the user to fill in the
project number and the scanner code to be logged in for future reference and
generating the test results in a desired fashion.
• The user is then taken to the test scanner page where he is asked to set the
chopper frequency and then the user just needs to click test start button.
• The system first initializes by starting the light source, the chopper at the set
frequency and the filter wheel at its default value.
• After the initialization of the system is complete, the scanner is set to start
collecting the data for a complete period of 2 mins. Each 20 sec interval within
this 2 min is for rotating the filter wheel by one filter segment. Hence; the
scanner gets to collect 20 secs of each kind of intensity of light source.
• After the period of 2 min the data collection stops and so do the simulating
devices.
• The user is then asked to either continue further by testing other flame scanners
or he is allowed to exit the application.
• If some kind of error occurs during the initialization of the system stage then the
application is halted till the user rectifies the specified error in the displayed
device and restarts the test.

6.1 The MSComm Control of Visual Basic

Figure 13 MSComm Control

This component of VB helps in serial communication processes. It was thus used to
establish communication with the three simulating components and the flame scanner
with the PC via serial ports of a “Serial Multiplexer Card” installed in the PC. This

Page 31 of 42

card helped in communicating with the flame scanner and the simulating devices
simultaneously via a single dedicated PC.
Following were the properties of the MSComm control used in the project:

For Light Source:
• Com Port – 3
• Settings – “9600, 8, N, 1”
• Rthreshold – 1
• Sthreshold – 1
• MSCommName – CommLight

For Light Filter:
• Com Port – 4
• Settings – “9600, 8, N, 1”
• MSCommName – CommFilter

For Light Chopper:
• Com Port – 5
• Settings – “19200, 8, N, 1”
• MSCommName – CommChopper

Page 32 of 42

6.2 “Welcome Page”

Figure 14 the Welcome Page

Components Required:
• Standard Form
• 4 Command Buttons
• 1 Text Box
• 1 Label
• 2 Timer Controls

6.2.1 Code
Dim lol As Boolean

Private Sub ABOUT_Click()
Text1.Text = "THIS APPLICATION IS DEVISED TO ASCERTAIN THE
FUNCTIONALITY OF THE SCANNER MORE ACCURATELY THAN THE
LEGACY SYSTEMS." & vbCrLf
Text1.Text = Text1.Text & "IT IS HIGHLY USER FRIENDLY AND
COMPATIBLE FOR USE ON SYSTEMS WITH WINDOWS 98/NT/XP/VISTA."

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End Sub

Private Sub FINISH_Click()
chk = MsgBox("DO YOU WANT TO END THE APPLICATION?", vbYesNo,
"VERIFY")
If chk = vbYes Then
End
End If
End Sub

Private Sub Form_Load()
Text1.Text = ""
Timer1.Enabled = True
End Sub

Private Sub HELP_Click()
Text1.Text = "Fit the Scanner head on the testmount.Connect the RS232 terminals to
PC." & vbCrLf
Text1.Text = Text1.Text & "1)CommPort3 - Light Source." & vbCrLf
Text1.Text = Text1.Text & "2)CommPort4 - Filter Wheel." & vbCrLf
Text1.Text = Text1.Text & "3)CommPort5 - Optical Chopper" & vbCrLf
Text1.Text = Text1.Text & "4)CommPort6 - Flame Scanner" & vbCrLf
End Sub

Private Sub PROCEED_Click()
WELCOME.Hide
DETAILS.Show
End Sub

Private Sub Timer1_Timer()
If Text1.Width <= 6855 Then
Text1.Width = Text1.Width + 45
Else
PROCEED.Enabled = True
HELP.Enabled = True
ABOUT.Enabled = True
FINISH.Enabled = True
Timer1.Enabled = False
End If
End Sub

Page 34 of 42

If lol Then
Label1.BackColor = &H404000
Label1.ForeColor = &HFFFFC0
Else
Label1.BackColor = &HFFFFC0
Label1.ForeColor = &H404000
End If
lol = Not lol
End Sub

Page 35 of 42

6.3 “Details” Page

Figure 15 the Details Page

• 1 Frame
• 2 Label Boxes
• 2 Text Boxes

6.3.1 Code
Private Sub BACK_Click()
Me.Hide
WELCOME.Show
End Sub

Private Sub NEXT_Click()
If Text1.Text = "" Or Text2.Text = "" Then
MsgBox "PLEASE ENTER DETAILS!"
Else
Me.Hide
Page 36 of 42

TEST.Show
If TEST.CommLight.PortOpen = False Then
TEST.CommLight.PortOpen = True
End If
If TEST.CommFilter.PortOpen = False Then
TEST.CommFilter.PortOpen = True
End If
If TEST.CommChopper.PortOpen = False Then
TEST.CommChopper.PortOpen = True
End If
End If
End Sub

Private Sub SAVE_Click()
If Text1.Text = "" Or Text2.Text = "" Then
MsgBox "PLEASE ENTER DETAILS!"
Else
project = Text1.Text
code = Text2.Text
Text1.Locked = True
Text2.Locked = True
On Error GoTo filerror
Open "C:Documents and SettingsAll UsersDesktopRecords.xls" For Append As #1
temp = project & " " & code & vbCrLf
Print #1, , temp
Close #1
MsgBox "Data Saved."
SAVE.Enabled = False
Exit Sub
filerror:
MsgBox "Error in updating records."
End If
End Sub

Page 37 of 42

6.4 “Test” Page

Figure 16 Test Page

• 4 MSComm Controls
• 4 Timer Controls
• 2 Progress Bars
• 2 Label Boxes

6.4.1 Code
Dim j As Integer

Private Sub Command1_Click()
j=1
Timer3.Enabled = True
Command1.Visible = False
CommChopper.Output = "R"
CommFilter.Output = "FILTER 1" & vbCrLf

Page 38 of 42

CommLight.Output = "START" & vbCrLf
End Sub

If CommChopper.PortOpen = True Then
CommChopper.PortOpen = False
End If
If CommFilter.PortOpen = True Then
CommFilter.PortOpen = False
End If
If CommLight.PortOpen = True Then
CommLight.PortOpen = False
End If
chk = MsgBox("Do You Want To Test More Scanners? ", vbYesNo, "Enquiry")
If chk = vbYes Then
DETAILS.Show
Me.Hide
Command1.Visible = True
DETAILS.Text1.Locked = False
DETAILS.Text2.Locked = False
DETAILS.Text1.Text = ""
DETAILS.Text2.Text = ""
DETAILS.SAVE.Enabled = True
Else
End
End If
End Sub

Dim BUFFER As String
CommChopper.Output = "E"
Do
DoEvents
BUFFER = BUFFER & CommChopper.Input
Loop Until InStr(BUFFER, "r)")
MsgBox BUFFER
BUFFER = ""
CommChopper.InBufferCount = 0
End Sub

Page 39 of 42

If ProgressBar1.Value < ProgressBar1.Max Then
ProgressBar1.Value = ProgressBar1.Value + 1
Else
temp = MsgBox("DATA PROCESSING COMPLETE!!", vbExclamation, "FINISH")
ProgressBar1.Visible = False
ProgressBar1.Value = 0
Label1.Visible = False
CommLight.Output = "STOP" & vbCrLf
End If
End Sub

Dim OUTBUFF As String
Select Case j
Case 2
OUTBUFF = "FILTER 2" & Chr$(10)
CommFilter.Output = OUTBUFF
Case 3
Case 4
Case 5
Case 6
Case Is > 6
End Select
j=j+1
End Sub

Page 40 of 42

7. Result
The three major components of simulation were successfully interfaced with the PC.
They were also successfully programmed using serial communication principles using
RS – 232 standard. The programming for varying the Optical Chopper frequency took
quite a long time, but ultimately it could be successfully done using the PC. In the
final page, all the three devices were simultaneously manipulated at one time.
Moreover, the system was partially automated to allow minimum user involvement
thus reducing the possibilities of manual errors. Due to some unavoidable
circumstances and conditions the scanner head could not be completely interfaced
with the PC and thus its testing procedure wasn’t complete. This also led to the
incomplete coding of the final form – “Test Form”. Apart from this sole technical
glitch, the project was completely in operating condition for the rest of the devices.

The learning part of the project was a highly fruitful one. Many aspects of data
communication, including serial communication, were of high importance.
Understanding of these concepts would definitely enable one to handle any kind of
electronic devices and communicate with them remotely.

Page 41 of 42

Bibliography
- Data Communication and Networking – Behrouz A. Forouzan
- Manuals Of Light Source, Light Filter, Light Chopper
- Electronic Devices and Circuit Theory – Robert L. Boylestad & Louis
Nasheslsky
- MATLAB Help Files
- MSDN Help Library of Visual Basic 6.0

Page 42 of 42

Report on Design of Automatic Flame Sensor Testing

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