PROJECT : CAP3030 08/03/2005 Technical Documentation CAP3030

TECHNICAL DOCUMENTATION
OPACITY TRANSDUCER
CAP3030

© CAPELEC 126 Rue Emile Baudot 34000 MONTPELLIER 1

PROJECT : CAP3000 08/03/05 HOM3000A.DOC

© CAPELEC 126 Rue Emile Baudot 34000 MONTPELLIER 2

PROJECT : CAP3000 08/03/05 HOM3000A.DOC

CONTENTS
1. INTRODUCTION...................................................................................................................................... 1
2. NORMATIVE REFERENCE .................................................................................................................... 1
3. CHARACTERISTICS OF THE MAIN COMPONENTS............................................................................ 1
3.1. Sampling device............................................................................................................................. 1
3.2. CASE ............................................................................................................................................. 1
3.3. Measurement cell .......................................................................................................................... 2
3.3.1. ..............................................................................................................................Description2
3.3.2. ....................................................................................................................... Effective length2
3.3.3. ..................................................................................................................... Walls of the tube3
3.3.4. ...................................................................................................................... Window sooting3
3.3.5. ................................................................Water condensation on the measurement cell wall3
3.4. Light source ................................................................................................................................... 3
3.5. Detector ......................................................................................................................................... 3
3.6. Power supply ................................................................................................................................. 3
3.7. Ventilation ...................................................................................................................................... 4
4. PERFORMANCES................................................................................................................................... 5
4.1. Measurement chain ....................................................................................................................... 5
4.2. Scale range.................................................................................................................................... 5
4.3. Resolution ...................................................................................................................................... 6
4.4. Accuracy ........................................................................................................................................ 6
4.5. Response time ............................................................................................................................... 6
4.5.1. ...........................................................................................................Physical response time6
4.5.2. ............................................................................................................ Electric response time6
4.6. Measurements different from opacity ones ................................................................................... 7
4.7. CPU technology ............................................................................................................................. 7
5. SPECIFIC INFORMATION ON SOME INTERNAL FUNCTIONS OF THE TRANSDUCER .................. 7
5.1. Zero................................................................................................................................................ 7
5.2. Linearity control.............................................................................................................................. 7
5.3. Lenses sooting............................................................................................................................... 7
5.4. Protections on the heating ............................................................................................................. 8
5.5. Autosleep ....................................................................................................................................... 8
6. COMMUNICATION .................................................................................................................................. 9
6.1. P.C.link........................................................................................................................................... 9
6.2. General principle............................................................................................................................ 9
6.3. Common frame of the commands ................................................................................................. 9
6.4. Unvalid commands ...................................................................................................................... 10
7. COMMUNICATION COMMANDS ......................................................................................................... 10
7.1. Command : Sending of the number of version and serial number.............................................. 10
7.2. Command : non filtered opacity ................................................................................................... 10
7.3. Command : Filtered opacity......................................................................................................... 10
7.4. Command : Zero .......................................................................................................................... 11
7.5. Command : Sending of the measurement table .......................................................................... 11
7.6. Command : Demand to set the acquisition.................................................................................. 12
7.7. Command :Trig for the sampling ................................................................................................. 12

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7.8. Command : Stop of the sampling ................................................................................................ 12

7.9. Command : Reading of the EEPROM ......................................................................................... 12
7.10. Command : Writing in the EEPROM ...........................................................................................13
7.11. Command : Intensity of the light source ...................................................................................... 13
7.12. Command : Driving of the fan ...................................................................................................... 13
7.13. Command : Selection of the measurement filter ......................................................................... 14
7.14. Command : Minimum value of the gas temperature ................................................................... 14
7.15. Command : Maximum value of sooting of the optical device ...................................................... 15
7.16. Command : Reading of the opacity curve segment by segment................................................. 15
7.17. Command : Current factor of acquisition ..................................................................................... 16
7.18. Command : Value of the smoke peak .........................................................................................16
7.19. Command : Various internal data ................................................................................................ 16
7.20. Command : Adjust the gain of the detector .................................................................................17
8. ADVISED ALGORITHMS ...................................................................................................................... 18
8.1. Start-up of the transducer ............................................................................................................ 18
8.2. Zero.............................................................................................................................................. 18
8.3. Measurement of an acceleration ................................................................................................. 18
9. EEPROM MAPPING .............................................................................................................................. 19
10. EXPLODED GENERAL DRAWING....................................................................................................... 20
11. ASSEMBLED DRAWING....................................................................................................................... 20

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PROJECT : CAP3030 08/03/2005 Technical Documentation CAP3030

1. INTRODUCTION
The new opacity transducer designed by the CAPELEC’s R&D team benefits from the most advanced
technologies. It is compact, light, and reliable.
We feel sure that it will give you complete satisfaction by allowing you to position yourself on the
smokemeter market with a different product, particularly robust and economically attractive.

2. NORMATIVE REFERENCE
The opacity transducer CAP3030 is designed according to the specifications of the NF R 10-025 French
standard. Consequently, it does meet the European regulations or any other regulation which would refer,
from the point of view of the measurement, to the European guidelines.

3. CHARACTERISTICS OF THE MAIN COMPONENTS

3.1. Sampling device

Several size available depending on the country regulation and customer's

request.
3.2. CASE

Strongly build made to be resistant against chocks and vibrations, dirty

environnement, light rain, EMI emission.
Size: 200 mm x 400 mm x 170 mm.
Weight: 5.600 Kg.

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3.3. Measurement cell

3.3.1. Description

OPACITY TRANSDUCER CAP3030

Functional schema of the measurement cell.

4
7

1 3 2
5
6

Air pur
Gaz d'échappement

1- Source board
2- Detector board
3- Temperature sensor of the cell
4- Heating elements
5- Gas temperature sensor
6- Gas input
7- Measurement cell
8- Exhaust fan

3.3.2. Effective length

3.3.2.1. Effective length of the sample

The effective pathlength is equal to 215 mm. after measurement.
It corresponds to the average width of the smoke column at the level of the beam of light. The values which
are sent from the transducer to the PC (via a RS232 communication) are directly compensated by this value.
The effective length to be used for the opacity calculations in m-1 must be done with an effective length of
430 mm.
3.3.2.2. Influence of the pressure of the exhaust gas and of the diameter
of the exhaust system.
The effective length of the system depends on the perpendicular air flow produced by the ventilation device.
It can be at least equal to to the tube length and at the most equal to the distance between both lenses.

Thus, the control of the ventilation allows to be sure that the true effective length do not distance too much
from the effective length used in the calculations.

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3.3.3. Walls of the tube

The inner surface of the measurement cell is black-mat-anodic-aluminium made so that to avoid all reflection
of the light emitted on the walls. The opacity transducer is a tube of 215 mm (± 0,5 mm) long with an internal
diameter of 21 mm.
Small particles of soot form a deposit on the internal surface of the cell. This does not modify the result of
the measurements. Actually, the soot which forms a deposit cannot be a screen between the source and the
detector unless the layer is too thick to reduce the internal diameter of the cell, what is not conceivable.
Nevertheless, it is advised to clean the cell once a month with the brush provided with the smokemeter and
dedicated to that use. There could be the risk that big particles take shape through their inertia and once
away from the wall could come through the fresh air flow to form a deposit on the lenses.

3.3.4. Window sooting

Only the too heavy particles can go through the perpendicular air screen which comes from the fan. These
particles go out from the area in which is the sample and some of them form a deposit on the windows. This
kind of event is relatively unfrequent. A cleaning of the windows once a month is enough to maintain the
transducer. If too much soot has settled on the windows, the CAP3030 sends a status bit and the
measurements must be invalidated as long as the maintenance has not been carried out. The lenses must
be cleaned with a dry cotton-duster.

3.3.5. Water condensation on the measurement cell wall

The tube is maintained at 80 °C, temperature from which the gas condensation on the wall hardly exists.
This temperature is enough so that, in the worst conditions, the humidity does not settle on the cell walls.

3.4. Light source

The light source is a green LED controlled by the microcontroller. It emits a visible light between 480 nm and
680 nm with a peak value of 565 nm. The LED emits pulses in a synchronous way at 20 ms so that to
reduce the noise due to the ambient static light. The source is protected by a convex lens, which lessens
the reflections on the walls of the measurement cell. Every 20 ms, the light source alternatively switches on
and off so that the detector can detect the state corresponding to an opacity equal to zero (light on and
invisible gas in the cell) and to an opacity equal to 100 % (light off, then, complete darkness simulating the
maximal opacity, no light source detected). This allows to compensate the light external to the system
(ambient light intensity).

3.5. Detector
The detector is a photodiode. Lens-protected, it collects the light coming through the gas sample. The
detector is maintained in temperature at 45 °C so that to avoid the variations of sensitivity due to the
temperature. When autozeroing, the detector successively sets in the state corresponding to an opacity
equal to zero (light on) and in the state corresponding to an opacity equal to 100 % (light on). Whatever the
protection lenses and the wall of the measurement cell are, one is able to give a sensitivity factor allowing to
make the measurement free from the sooting.
An automatic gain control of the detector signal does allow to adjust the full scale for optimizing the
accuracy.

3.6. Power supply

The CAP3030 has been designed to be powered either in 13.5 VDC, 110 VAC and 230 VAC.

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Continuous voltage power supply :

Operating range : 13.5 VDC ±15 %
Required power : 65 W

Alternating voltage :
Operating range : 110-230 VAC +10 % -15 %.
Frequency : 50-60 Hz ±2 %

Further information : complies with the EC requirements.(CE certificate available on request)

3.7. Ventilation
The transducer is equipped with a flat-set fan so that to improve its lifetime (62,500 hours).
This fan allows to prevent the lenses from sooting, to maintain the effective length and to favour gas
evacuation. It allows an air flow over 10 l/s for each end of the tube. The good operation of the fan is
possible due to the continuous measurement of its speed of rotation.
A bit of status sets when this speed goes out of the given range.
So that to spare this component which is quite often working, the CAP3030 allows to drive the starting and
the stop of the fans. This allow to improve the life time of the fan again.
The fan is also equipped with an rpm sensor which allows to control the air flow. If the fan speed becomes
out of the limits, a status bit is activated and the effective path length may be different.

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4. PERFORMANCES
4.1. Measurement chain

Signal of the
detector amplified

Conv. Ana./Num. of the signal : <Ma> and <Me>

Ma : LED ON / Me : LED OFF command ‘U’
Calculation of the relative intensity with
regard to the zero conditions +linearity <Nbrut (%)>
compensation. Opacity calculation command ‘0x8B’

K=-(1/0.215)xLn(IR)
Opacity converted in K

Filtering

<N430(%)>
-1 current opacity
Conversion from k(m ) in N(%)
Command ‘u’
N=100x(1-EXP(-k x 0.430)) <N430(%)[0..500]>
Compensation effective length (curve)
command 0x8A

Résult :
Ri = max (N[0..500]) (%) k
< i>
Ki=-Ln(1-(Ri/100))/0.430 command ‘b’

¾ Conversion of N in k : Ki=-Ln(1-(Ni/100))/0.430
(Ln() being the Napierian logarithme function)
N is expressed in % and k is expressed in m -1.
All the required mathematical elements are integrated so that the transducer provides directly the selected
opacity value (maximum of the filter curve either on K or on N or on both of them).
Before each test, it is necessary to make sure that the filter (coefficient Cn and Ck) stored in EEPROM is
well parametered.

Work carried out by the computer :

- Reading via the communication port of the opacity curve in percent,

- Conversion of the opacity in K(m-1) with L = 430 mm and display (as an option),
- Reading via the communication port of the selected opacity peak in m-1,
- Display of the selected peak value.

4.2. Scale range

N value :

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Scale range from 0.00 to 99.9 %.

K value :
Scale range from 000 to 9.99 m-1.

4.3. Resolution
The opacity obtained in percent of the transducer is given for 0.1 % of resolution.
The maximal value of the opacity curve obtained in m-1 is sent with a resolution of 0.001 m-1.

4.4. Accuracy

• < 1.0 % of opacity in the full range.

• < 0.5 % guaranteed at final check in production.
4.5. Response time

4.5.1. Physical response time

This is the time between the moment when a gas sample goes out of the exhaust pipe and the moment
when the transducer measures the gross incident opacity (non-filtered), the precision being respected.
< 0,200 seconds.

4.5.2. Electric response time

This is the time for the transducer to display 90 % of the value of an opacity which went from 0% to 100 %
for t=0s.
This time depends directly on the type of applied filter on the opacity curve.

Exemple:

For a 1 second response time, it is recommended to use the following constants (approved in France with
these constants):
- Cn=0.141
- Ck=0.046
It is strongly recommended to ask CAPELEC's support in order to determine the most adapted constants
relative to a specific requirement on response time.

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4.6. Measurements different from opacity ones

Measurements Sensor type Normal Measure- Typical value Resolution

range of ment accuracy
operation range
of the measurement
Temperature of the 40..50 0..128 45 1
detector (°C) 2%
Ambient 0..50 0..128 1
Temperature (°C) 2%
Temperature of the 60..150 0..128 80 1
tube (°C) 2%
Gas temperature (°C) 40..230 0..256 >40 1
1%
Fan speed of rotation Hall 2400.. 600.. 2700 100
(RPM) 2900 9999 5%
CPU power supply CAN 11.54.. 0..24 13.5 0.01
voltage (V) 15.53 2%

4.7. CPU technology

LOW COST MOTOROLA 68HC11E1 (8 bits-2 MHz)

5. SPECIFIC INFORMATION ON SOME INTERNAL FUNCTIONS OF

THE TRANSDUCER
5.1. Zero
When autozeroing, the light source alternatively switches on and off so that the detector can detect the state
corresponding to an opacity equal to zero (light on and invisible gas in the cell) and to an opacity equal to
100 % (light off and then absolute dark simulating a maximal opacity, no light source detected).
From both these measurements, the transducer carries out a correction on the measurement so that the
opacity is null in the conditions of zero.
The zero must be made before each measurement on a vehicle. It is advised to integrate it in the test
procedure at the beginning before the probe is put into the exhaust pipe.

5.2. Linearity control

It is possible to set the light intensity of the LED to a value comprised between 0 % and 100 %. (32 different
opacity levels). It allows to do a fast control of the eventual variations in accuracy (one point) and linearity
(several points) due to in use conditions.

5.3. Lenses sooting

Due to an eventual sooting of the transducer windows, the intensity of the LED can be attenuated. If the
attenuation brings a less important intensity than the authorized limit, a corresponding bit of status is set.
The setting of this bit implies that the user must clean the windows of the transducer. This control is carried
out for each zero.
The cleaning factor of the windows corresponds to the minimum threshold of the intensity so that to respect
the linearity of the operations in the field. At the manufacturing stage, this limit is set at 50 % and stored in
the EEPROM. This limit (cleaning factor of the windows) in % represents the maximum level of intensity
which is available after the manufacturing of the transducer. This maximal value of intensity too is stored in
the EEPROM.

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5.4. Protections on the heating

The measurements of temperature control themselves each other. During preheating period, the CAP3030
controls that the regulations in temperature works correctly. During the measurement, any anomaly of a
temperature enslaving a regulation brings about the stop of the heating.
This reduces the risks of overheating due to a defective running of the regulation or of the temperature
probe.

5.5. Autosleep
The transducer can be parametered in order to switch to standby automatically. It can be also switched to
standby and deactivated with a command.
Autosleep setting just implies the fan stop. The heating elements keep on being regulated at the same
temperatures.
Autosleep setting is done automatically x minutes after the las t command which was sent via the serial port.
The x value is implemented in the EEPROM and can be modified by the user interface (by default x=5).
To disactivate the autosleep, x has to be set at 0.

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6. COMMUNICATION
6.1. P.C.link
The communication is made by an RS232 serial port. The connecteur does also allow to power the
smoke head at 13.5 VDC.

Connector type: AMP réf.

Pin 1- POWERIN +
Pin 2- Rx (serial com)
Pin 3- Tx (serial com)
Pin 4- POWERIN -
Pin 5- Gnd (serial com)
Pin 6- Chassis ground
Pin 7- POWEROUT +
Pin 9- POWEROUT -

RS232 parameters:
- Speed : 9600 Bauds
- Data : 8 bits
- Parity : No (0)
- Stop : 1 bit

6.2. General principle

The driving of the transducer via the serial port is very easy to be implemented. Each command is composed
of an ASCII character, of arguments (depending on the command) and of a checksum.
The transducer must answer to each command that it receives within 30 ms after the reception of the last
character of the command.
The system that drives the transducer must send only one command at the same time, that is to say that it
must wait for the answer of the transducer whatever right or bad.

6.3. Common frame of the commands

Syntax of all commands is a follows :

Sending : <command character>[<data 1>...<data n>]<checksum>

Byte: 1 n 1
checksum=-(sum[1..n+1] of the bytes) modulo 256
Toral number of characters : n+2

Reception:<commande character>[<data 1>...<datat n>]<checksum>

1 n 1

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6.4. Unvalid commands

When the PC calls for a non-existing function or when there is an error of syntax or of communication, the
transducer sends a NAK.

Reception: <NAK=0x15><checksum=0xEB>

7. COMMUNICATION COMMANDS
7.1. Command : Sending of the number of version and serial number

This command allows to know the number of version of the CAP3030.

Request: <‘v’><checksum>
Answer : <‘v’><version><Serial number><checksum>
Bytes:1 2 2 1
Format :
Version : Unsigned integer
Cast in float and divide by 100 to display x.xx
Serial number : Unsigned integer

7.2. Command : non filtered opacity

This command sends to the PC the current gross non-corrected opacity.
This value does not take into account the filters, the effective length and any other compensation.

Request: <0x8b><checksum>
Answer : <0x8b><opacity><checksum>
Bytes:1 2 1
Format:
Opacity Unsigned integer equal to the opacity *10 (to display xx.x %)

Remark : one must use this command when one wants to make a measurement in static with an
optical filter so that to control the accuracy of the measurement.

7.3. Command : Filtered opacity

This command sends to the PC the current opacity (current opacity * 10 internally refreshed every 20ms),
the emission gas temperature (in °C), the temperature of the tube (in °C) and the information bits of the
current status of the CAP3030.

Request: <‘u’><checksum>
Response: <‘u’><opacity><gastemperature><temperaturetube><status><checksum>
Bytes:1 2 1 1 2 1

Description of the Bytes status of the CAP3030:

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b1.0 Ambient temperature unvalid (0 °C,50 °C)

b1.1 Detector temperature unvalid (40 °C,50 °C)
b1.2 Tube temperature unvalid (60 °C,150 °C)
b1.3 Power supply continuous voltage out of tolerance (11.54..15.53 V)
b1.4 State of the fan (1=ON, 0=OFF)
b1.5 Reserved
b1.6 Opacity non available
b1.7 Transducer in standby mode (1=Yes, 0=No)
b2.0 Zero running (also active after a reset, cleared after a
zero)
b2.1 Sooting of the lenses
b2.2 Acquisition triggered
b2.3 Trigger activated
b2.4 Fault of the fans (2300..2900 rpm)
b2.5 Gas temperature too cold (comparison with EEPROM value)
b2.6 UNUSED
b2.7 Fault on a temperature sensor (heating of the tube cut)
Format :
Opacity Unsigned integer equal to the opacity *10 (to display xx.x %)
Gas Temp. Unsigned char (8 bits)
Tube Temp. Unsigned char (8 bits)

7.4. Command : Zero

This commands asks to the CAP3030 to make a linearization. It allows to fix the values of the O % and of the
100 % of opacity.

Request: <‘l’><checksum>
Response: <‘l’><checksum >
Byte: 1 1

7.5. Command : Sending of the measurement table

This command asks for the CAP3030 to send the 10 seconds of measurements which follow the set and
triggered order. The sampling array is made of 500 words of data (1000 bits).
This command must be used after that the table has been filled up when the transducer is no more in the trig
mode (status bit B2.3 deactivated ((=0) ).

Request: <‘o’><checksum>
Response: <‘o’><opacity array><checksum>
Byte: 1 500*2 1
Format :
500 Unsigned integers equal to the opacity*10 (to display xx.x %)

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7.6. Command : Demand to set the acquisition

This command asks for the CAP3030 to set the acquisition routine of an opacity curve. The transducer
resets the 10 seconds of the data buffer and starts to collect the information in a buffer memory of 1 second
in continuous. This command must be followed either by the command of the trig ‘t’ or by the command of
stop ‘q’.

Request: <‘a’><checksum>
Response: <‘a’><checksum>
Byte: 1 1

7.7. Command :Trig for the sampling

This command asks the CAP3030 to store in the buffer the 9 seconds of data which follow this command.
Following this command, one has a buffer of 10 seconds which contains 1 second of pre-triggered data (set
command) and 9 seconds of triggered data.

Request: <‘t’><checksum>
Response: <‘t’><checksum>
Byte: 1 1

7.8. Command : Stop of the sampling

This command asks for the CAP3030 to reset the trigger and to stop writing data in the buffer. The set state
too is given up.

Request: <‘q’><checksum>
Response: <‘q’><checksum>
Byte: 1 1

7.9. Command : Reading of the EEPROM

This command reads the EEPROM data at a specific address.

Request: <‘m’><m1><m2><checksum>
Byte: 1 1 1 1
Format :
m1: starting address in the eeprom (unsigned char)
m2 : number of bits to read (unsigned char)

Response: <‘m’><d1><d2>...<dm2><checksum>
Byte: 1 1 1 1 1
di : i ème byte asked by the user
Remark : di is the byte placed at the address m1+i of the eeprom.

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7.10. Command : Writing in the EEPROM

This command allows to write in the EEPROM at a specific address.

Request: <‘n’>< n1>< n2><d1>...<dn><checksum>

Byte: 1 1 1 1 1 1
Format :
n1 : offset on the address (unsigned char)
n2 : number of bits to write (unsigned char)
di : i ème byte to write into the EEPROM.
Response: <‘n’><checksum>
Byte: 1 1

Remark : di is written in EEPOM at the address n1+i.

Enclosed the EEPROM mapping.

7.11. Command : Intensity of the light source

This command allows to fix the light intensity of the source.

Writing :

Request: <‘c’><s><l><checksum>
Response: <‘c’><checksum>
Format :
s.7=0 writing of the value in memory
l is an unsigned char between 0 and 100.

Reading

Request: <‘c’><s><checksum>
Response: <‘c’><s><l><checksum>
Format :
s.7=1 reading of the value in memory
l is an unsigned char between 0 and 100.

The value by default when starting up is 100 %. If l=50, then the light intensity will be of 50 %.
This routine allows to carry out a drift control procedure on the measurement.
The opacity source intensity can be set to 32 different positions between 0 and 100 %. By giving the
intended opacity with this command, the smokemeter set the source intensity to the nearest position. It is by
this way possible not only to check the 50 % intensity drift but also the complete linearity drift on the full
range.

7.12. Command : Driving of the fan

This command allows to start and stop the fan of the transducer.

Request: <‘s’><s>checksum>
Response: <‘s’><s><checksum>
Format :
s=0 Stop of the fan.
s=1 Starting up of the fan.

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(s is a word of 8 bits.)

7.13. Command : Selection of the measurement filter

This command allows to select the filters and the coefficients as well which are used to carry out a
measurement.

Writing:

Request: <‘e’><s><Ca>[<Cb>]<checksum>
Byte: 1 1 2 [2] 1
Response: <‘e’><checksum>

Format :
s.7=0 writing of the value in memory
Byte s :
s.0 s.1 : number of poles (0, 1 or 2).
s.4 filter on k and N if bit active.
s.5 BESSEL FILTER if bit active.
s.6 UNUSED.

Reading :

Request: <‘e’><s><checksum>
Response: <‘e’><s><Ca>[<Cb>]<checksum>
Byte: 1 1 2 2 1

Format :
s.7=1 reading of the value in memory

example :
Filter on k and N
Writing in the transducer
Ca=0.141
Cb=0.046
Sending: <‘e’><0x92><00 ;141><00 ;46><checksum>

BESSEL FILTERING:
When using BESSEL filter (S=0xA2):
The Omega value is transmitted with Ca and Cb. Ex:
- Response time= 1.00 S.
- Physical response time= 0.2 s
- Sampling time= 0.02 S.
- Omega=50.554657
For this configuration, you it will be sent to the CAP3030 the following command:
Sending: <‘e’><0xA2><0x13;0xbf><0x12;0x31><checksum>
5055=0x13bf 4657=0x1231.
The omega used in the bessel filter will be calutated as Omega=(Ca + Cb/10000)x100.
In the exemple case, omega=(5055+4657/10000)x100=50.554657

7.14. Command : Minimum value of the gas temperature

This command allows to fix or to know the gas temperature from which the measurement is considered as
right. This value is written in EEPROM.
It is fixed by default at 40 °C.

Writing:

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Request: <‘h’><s><tgaz limite><checksum>

Response: <‘h’><checksum>
Format :
s.7=0 writing in EEPROM
tgaz limite is an unsigned char

Reading :
Request: <‘h’><s><checksum>
Response: <‘h’><s><tgaz limite><checksum>
Format :
s.7=1 reading of the EEPROM

Remark :
tgaz limite must be fixed between 0 and 255°C.

7.15. Command : Maximum value of sooting of the optical device

This device allows to fix the minimum intensity of light which has to be received when the cell is empty. If the
value is below than the one fixed, the optical device must be cleaned. The corresponding status bit will be
affected at 1 (b2.1=1).
This value is a percentage of the maximal sooting. By default, this value is fixed at 50. The value is freezed
in the EEPROM.

Writing :
Request: <‘k’><s><Clean window><checksum>
Response: <‘k’><checksum>
Format :
s.7=0 writing in EEPROM
Clean Window is an unsigned char between 0 and 100.

Lecture:
Request : <‘k’><s><checksum>
Response: <‘k’><s><Clean window><checksum>
Format :
s.7=1 reading of the EEPROM
Clean Window is an unsigned char between 0 and 100.

Clean window must be within 0 and 100 %. The value by default is 50 %. A normal operating range of this
parameter corresponds to 30 % < Clean window <70%.

7.16. Command : Reading of the opacity curve segment by segment

When the transducer is triggered, this allows to get back the opacity curve during the sampling piece by
piece in function as and when required. The user asks to read the data from a moment n and until the
moment m. If the m-n points are not available at the moment of the demand, the unit replies by a NAK. On
the contrary, the unit sends the requested data table. This command allows to draw a curve in real time
without having to wait for the end of the 10 seconds of acquisitions.

Request: <0x8a><n><m><checksum>
Byte: 1 2 2 1
Response: <0x8a><Nn><Nn+1>...<Nm-1><checksum>
Byte: 1 2 2 1

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7.17. Command : Current factor of acquisition

When the transducer is acquiring, this command allows to know any time how many points have been
sampled.
The received value is equal to 50 at the moment when one sends the command ‘t’ (trig) and may be equal to
500 (size of the table).

Request: <w><checksum>
Response: <w><Indice><checksum>
Byte: 1 2 1
Format :
Indice is unsigned integer between 0 et 500.
Remark :
Using this command is indispensable if one wants to read the curve in real time with the command ‘0x8a’.

7.18. Command : Value of the smoke peak

This command allows to read after the acquisition of an opacity curve the opacity value linked to the
acceleration which must be selected. This value is expressed in k(m-1).

Request: <‘b’><checksum>
Response: <‘b’><Peak>< gas status >< duration of acceleration ><checksum>
Byte: 1 2 1 2 1
Format :
Peak Unsigned integer equal to 1000 times the opacity in m-1 .
(divide by one thousand in a float to get the format x.xxx)
gas status
Byte of 8 bits
=0 superior to the limit during of all the time of the acceleration,
≠0 Gas temperature inferior to the limit during the acceleration.
duration of acceleration
Unsigned integer between 0 and 500.
This is the number of points between the trig moment (factor=50) and the moment
when the opacity peak is reached.

7.19. Command : Various internal data

This command gives access to other measurements carried out by the transducer and that cannot be
reached by the above-defined commands. This command is not useful during an opacity measurement but
can be used by a service program.

Request: <‘U’><checksum>
Response: <‘U’><Temp gas><Temp tube><Temp detector><Temp ambient>…
Byte: 1 1 1 1 1
…<Power supply.><Fan speed.><lense dirtyness>…
2 2 1
…< LED OFF Intensity > < LED ON Intensity >…
2 2
…<EMPTY><checksum>.
11 1
Format :
Temp gas Unsigned char
Temp tube Unsigned char
Temp detector Unsigned char
Temp ambient Unsigned char

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Power supply Unsigned integer

equal to 100 times the voltage (divide by 100 in a float to get the resolution xx.xx)
Fan speed Unsigned integer
Lense dirtyness Unsigned char between 0 and 100 (clean lenses=100)
LED OFF Intensity Unsigned integer
LED ON Intensity Unsigned integer
EMPTY 11 empty characters reserved for future extensions

Remark :
This frame is composed of 26 characters including command and checksum.

7.20. Command : Adjust the gain of the detector

This command process an automatic gain control on the detector amplifier.

This is particularly interesting to be used if the LED ON intensity is too low even if
the lenses are clean. During the gain adjustment, check the 'zero running' statusbit
and wait this bit to be cleared before to do any other operation.
It is recommended to use this command only in service a menu (the operation
should not be done by the end user but only by people in charge of the service)

Request : <‘d’><checksum>
Response: <‘d’><checksum>
Rem: make a zero after sending this command.

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8. ADVISED ALGORITHMS
8.1. Start-up of the transducer
If b2.6 or b2.7 are active then stop the test, the transducer must be repaired.
Loop {
Use the command ‘u’ and wait for the error bits different than b1.1, b1.2,
b1.3, b2.4 are equal to zero.
Make a zero.
8.2. Zero
Loop {
Make a zero with command ‘l’.
Read status and opacity bits (command ‘u’) as long as b2.0=1
When b2.0=0 :
If all the bits different than b1.4 and b2.5 are null and the opacity is below
2.0 %, then leave the loop.
Otherwise, one keeps on with initialization and one leaves the test.
}
8.3. Measurement of an acceleration
Set the acquisition (command ‘a’)
Read the filtered opacity (‘u’) as long as variation below 0.20 m-1
If variation of opacity more than 0.20 m-1 (beginning of the acceleration)
Then trigger (‘t’)
loop{
Ask for factor (‘w’)
Ask for the points of the curve between previous factor and new factor (‘0x8a’).
New factor becomes previous factor.
} as long as high opacity (accleration on)
Leave the sampling (‘q’)
Ask for result (‘b’)
Display max

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9. EEPROM MAPPING
Variable Description Address in Size in Byte Value by default
EEPROM
STATUS Type of filter
0 1 0x92
POLE_K Value of the filter on the
curve N
1 2 141

POLE_N Value of the filter on the

curve K
3 2 46
T_THRESHOLD Mini. gas temperature
during the measurement
5 1 40
C_CLEANWINDOW Limit threshold of sooting
6 1 50
STANDBYTIME Waiting time before
standby(in minuts)
7 1 5
ZEROP Value of the intensity when
last zero
8 2 3000
RESERVED 10 2
RESERVED 12 1
GAINCONTROLi Value of the gain
13 1
RPMUPi Min value of RPM/1000
14 1 29
RPMDOWNi Max value of RPM /1000
15 1 21
POWERDOWNi Min value of power supply
16 2 2192
POWERUPi Max value of power supply
18 2 2989
TGASOFFSETi Sampling value of the gas
temperature sensor
20 1 0
RESERVED 21 1 Any value
NOSERIi Serial number of the unit
22 6 00100
RESERVED Reserved for future
extensions
28..50 23
USER Zone which can be used by
the customer
51..98 48
RESERVED2 Reserved Byte
Always 99 1 Always 0x00

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10. EXPLODED GENERAL DRAWING

11. ASSEMBLED DRAWING

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