BRUEL & KJAER 1306 User manual

InstructionManual
Vol.1
Toxic-gas Monitor Type 1306
Operation and Interface
The Toxic-gas Monitor Type 1306 is an E!X-
tremely reliable and highly selective monitor
of a gas, or group of gases. Gas-selectivity is
determined by the optical filter installed. The
1306 operates automatically- drawing in a
sample of air from its environment, at user-
selectable intervals, and measuring the con-
centration of the monitored gas in it. ·
The 1306 is linked
to a computer so that the
user can request measurement/test data from
it, and remotely control
it by sending it com-
mands and control data.
+ BrUel & Kjcer

Brilel & Kjcer ~
DK-2850 Nrerum ·Denmark· Telephone: [phone] ·Telex: 37316 bruka dk · Fax.: [phone]
Prinled 1n Denmark: K. Larsen & S0n A/S · DK·2600 Glostrup
1306
Vol.1
English OK BE0981-11
InstructionManual
Vol.1
Toxic-gas Monitor Type 1306
Operation and Interface
The Toxic-gas Monitor Type 1306 is an ex-
tremely reliable and highly selective monitor
of a gas, or group of gases. Gas-selectivity is
determined by the optical filter installed. The
1306 operates automatically-drawing in a
sample of air from its environment, at user-
selectable intervals, and measuring the con-
centration of the monitored gas in it.
The 1306 is linked
to a computer so that the
user can request measurement/test data from
it, and remotely control it by sending it
com-
mands and control data.
+ Bri.iel & Kjaer

TOXIC-GAS MONITOR
TYPE 1306
From serial no. 1336777
June 1988

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS {PRODUCT DATA) .............................................................................. 1
2. OPERATION .................................................................................................................................................................5
2.1. INTRODUCTION.................................................................................................................... 5
2.2. INSTALLATION OF THE MONITOR................................................................................... 6
2.3. THE MEASUREMENT PRINCIPLE .................................................................................... 6
Determination
of Water-vapour 's Signal Contribution ................................................. 7
2.4. THE GAS-MEASUREMENT SEQUENCE......................................................................... 7
Time Taken to Complete a Gas Measurement.............................................................. 8
2.5. OPERATING MODES........................................................................................................... 9
2.6. START
-UP SEQUENCE OF THE 1306 ............................................................................. 9
2.7.
SELF- TESTS......................................................................................................................... 9
Almost Continuous Self-tests............ .. ..........., .. .............................................................. 11
Regular Self-tests.............................................................................................................. 13
The Gas-measurement Sequence
Self-tests ................................................................ 16
2.8. CONDITIONS CAUSING THE 1306
TO RESET............................................................. 17
2.9. COMMUNICATING WITH THE 1306................................................................................ 18
Sending Data
to the 1306................................................................................................. 18
Requests
for Data from the 1306 ................................................................................... 20
Sending Commands to the 1306....................... ... ........................................................... 21
2.1 0. THE STATUS REPORT ...................................................................................................... 23
Warning Flags..................................................................................................................... 23
Operating-error Flags ....................................................................................................... 26
3. INTERFACE AND COMMUNICATIONS PROTOCOL.......................................................................................... 29
3.1. RS 485 INTERFACE ............................................................................................................ 29
Introduction ......................................................................................................................... 29
Differential Transmission..................................................................................................
29
Use of Equipment with an RS 232 C Interface.............................................................. 30
Large Systems................................................................................................................ .... 32
3.2. DDCMP PROTOCOL...................
.. ..................................................................................... 34
Introduction ......................................................................................................................... 34
Cyclic Redundancy Checking (CRC).............................................................................. 35
Data
Format ...................................... .. .. .............................................................................. 35
Message Headers.............................................................................................................. 35
Exchange
of Messages..................................................................................................... 38
Response
of the Computer to Errors ............................................................................ 39
Response
of the 1306 to Errors ...................................................................................... 41
Initializing the System....................................................................................................... 42
Block Data Transfers ........................................................................................................ 43

4. DATA TRANSFER BETWEEN THE 1306 AND THE COMPUTER ..................................................................... 44
4.1. INITIATING A
DATA TRANSFER ...................................................................................... 44
4.2.
DATA FORMATS ................................................................................................................. 45
4.3. CONTROL
DATA .................................................................................................................47
4.4. MEASUREMENT AND TEST
DATA ................................................................................. 48
Primary Data Block ...........................................................................................................48
Total Data Block ................................................................................................................. 50
Measurement Test Data Block ........................................................................................ 52
Software Test Data
Block ................................................................................................. 62
Access External Ports ....................................................................................................... 63
4.5. COMMANDS
TO THE 1306.............................................................................................. 64
Forced
Commands ............................................................................................................64
Test
Commands .................................................................................................................66
Order of Priority of Commands ...................................................................................... 68
Transfer of Commands .....................................................................................................68
4.6. EEPROM
DATA ...................................................................................................................69
Optical Filter Factors ........................................................................................................ 69
Optical Filter Identity ......................................................................................................... 71
Calibration Factors ............................................................................................................73
Calculating the CRC Check Sum.................................................................................... 75
4.7. ERROR STATUS FLAGS....................................................................................................
76
5. CALCULATION OF CALIBRATION FACTORS ...................................................................................................... 79
5.1. INTRODUCTION..................................................................................................................79
5.2. ANALYSIS OF THE SIGNAL MEASURED
IN THE ANALYSIS CELL ........................ 79
5.3. CALCULATION OF THE GAS CONCENTRATION ........................................................ 80
5.4. CALCULATION OF THE NEW CALIBRATION FACTORS ............................................ 82
Calculation of the New Concentration Offset Factor (Cottset) .................................... 82
Calculation of the New Humidity Gain Factor (91) ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 83
Calculation of the New Conversion Factor (fc)............................................................ 84
5.5. COMPARISON
OF THE "OLD" AND "NEW" CALIBRATION FACTORS ................... 85
5.6. TRANSFER OF THE NEW CALIBRATION FACTORS
TO THE 1306's EEPROM..... 86
6. SERVICE AND REPAIR............................................................................................................................................ 87 ·

USES:
• Unattended monitoring of toxic gases and
vapours
• Detection of accidental releases
• Monitoring of process emissions
• Occupational health and safety measurements
FEATURES:
• Highly selective and sensitive
• Linear over a wide dynamic range
• Unattended operation -typically 3 months
• Accurate concentration measurements
• Extremely reliable due to self-testing procedures
• Compensates for water-vapour and temperature
fluctuations
• Remotely controlled
by computer
• User-friendly software available
• Very
stable- infrequent calibration required
• Easily maintained- running-costs are low
• Protected against voltage surges
Introduction
The Brtiel & Kjrer Toxic-gas Moni-
tor Type 1306 is a highly sensitive,
stable
and reliable instrument de-
signed to automatically monitor toxic
gases
and vapours in harsh environ-
ments.
Its measurement technique is
based on photo-acoustic infra-red
spectroscopy.
The 1306 can thus be
used to monitor almost any gas which
abso:..·bs infra-red light. By choosing an
appropriate optical filter from the
wide range of narrow-band filters
available,
the 1306 can selectively
measure
the gas ofinterest. The 1306's
detection threshold is gas-dependent
but typically in the parts per billion
(109) to parts per million region. Its
wide dynamic range allows it to mea-
sure concentrations four orders of
magnitude (i.e. a factor of 104) higher
than its detection threshold.
BP 0788-11
The Toxic-gas Monitor's running-
costs are low as it is able to function
efficiently even under extreme envi-
ronmental conditions for long periods
of time without maintenance,
and
with minimal supervision.
The weather-proofed case of the
1306 encloses both the system for
measuring gas concentration,
and the
electronics for processing signals.
For long-term monitoring
the 1306
and its Power Supply ZG 0309 are
mounted on a
mast in a suitable loca-
tion,
and the 1306 is linked to a com-
puter. This computer acts as a control
station. Using
the Applications Dis-
kette BZ5003 provided, users can
communicate with a single 1306, con-
trolling
it remotely, collecting mea-
surement
and self-test data from it
and calibrating it in situ.
type 1306
Toxic-gas Monitor
Brtiel& Kjrer Application Software
Type 7619 is available for controlling
up to 31 Toxic-gas Monitors in a mon-
itoring network.
This user-friendly
software automatically collects, analy-
ses and presents measurement and
self-test
data from all the monitors in
a network,
and enables in situ calibra-
tion of each 1306 in
the network.
The measurement and self-testing
sequences of
the 1306 are completely
automatic. The 1306's comprehensive
self-testing procedures enable
it to de-
tect and identify any relevant system
fault and report
it to the control sta-
tion. Measurements stop if the 1306 is
unable to measure reliably because of
a system fault,
but as soon as the fault
has been corrected,
the 1306 automat-
ically resumes measurements.

Optical Window )
(Air Shunt
Infra-Red
Source
Optical Filter
UAXXXX
Humidity
Lamp
Inlet
·Valve (1)
Fine Air-Filter
Coarse
Air-Filter
87041111
Fig. 1. The measurement system of the Toxic-gas Monitor
Correct positioning of the 1306 is
vital.
The circulation of air around the
1306 must be sufficient to ensure that
the air around it is representative of
the air in the area being monitored.
Method of Operation
At user-selectable intervals, a pump
draws a sample of air from the moni-
tor's environment, into the analysis
cell, through two air-filters.
The cell is
then sealed by closing its inlet and
outlet valves (see Fig. 1). Light from
an infra-red source is reflected from a
mirror
and passed first through a
chopper, which pulsates it;
then
through an optical filter, which trans-
mits light of defined wavelength into
the analysis cell through a window.
The light transmitted by the optical fil-
ter is selectively absorbed by the gas
being monitored, so if any of the moni-
tored gas is present in the cell it will
absorb this light, causing the tempera-
ture of the gas to increase.
As the cell is
sealed, this temperature increase causes
an equivalent increase in the pressure
ofthe gas. Because the light is pulsating
at the chopper frequency, the pressure
will also fluctuate
at this frequency,
creating
an acoustic wave in the cell
which is directly proportional to the
concentration of the gas in the cell.
This is the photoacoustic effect.
Two sensitive microphones mount-
ed within
the cell wall measure the
acoustic signal which is then processed
by
the 1306. Measurement results are
sent to the control station on request.
2
A complete measurement takes 45-
55 s - this includes the time taken to
purge the cell. The time between mea-
surements is defined by the user.
Selectivity
The selectivity of the Toxic-gas
Monitor is determined by
the installed
optical filter. A wide range of narrow-
band optical filters is available from
Brtiel& Kjrer. By studying the absorp-
tion spectrum of the gas to be moni-
tored as well as the absorption spec-
trum of any other gas which is likely
to be found in the ambient air in the
same area, the most appropriate opti-
cal filter can be chosen. Refer to the
Product Data Sheet for the Optical
Filters for details.
Water vapour, which is nearly always
present in the air samples drawn into
the 1306 for analysis, absorbs infra-red
light slightly
at nearly all frequencies
and therefore contributes to the signal
measured in the cell. However, by us-
ing a humidity lamp, water-vapour's
contribution is measured separately
during each gas measurement se-
quence, so that the 1306 can compen-
sate for water-vapour's interference.
Setting-up the 1306
The user sets-up the monitor by
sending
it control data which specifies
the following:
• the time between the finish of one mea-
surement and the start of the next (this
determines the measurement frequency);
• the alarm level- t4at is, the con-
centration of monitored gas which, if
measured, causes the 1306 to perform
measurements continually,
and trig-
gers any external alarm which may be
connected to
the network.
Modes of Operation
The 1306 has four different modes
of operation.
Three of these modes are
dependent upon
the concentration of
monitored gas measured in the analy-
sis cell (see Fig. 2).
(1) Normal Mode
The 1306 operates in this mode as
long
as the concentration of the moni-
tored gas it measures is below a level
called the intensification level.
The in-
tensification level is half the alarm
level (see Fig. 2). Gas measurements
occur with a frequency specified
in the
1306's control data.
(2) Intensification Mode
The 1306 operates in this mode as
soon as it measures a concentration of
monitored gas which is greater than
the intensification level. While operat-
ing in this mode the frequency of gas
measurements increases as
the moni-
tored-gas concentration increases, un-
til the alarm level is reached.
(3) Alarm Mode
By the time the concentration of the
monitored gas reaches the alarm level
gas measurements are being taken
continually.
( 4) Power- Down Mode
The 1306 operates in this mode: (a) if
it is not able to measure gas concentra-
tions reliably, or (b) if commanded to do
so by the control station (e.g. during
maintenance). In this mode the 1306
stops performing gas measurements and
stops testing its measurement system.
Gas__.
Intensification Alarm Concen-
level Level tration 87041411
Fig. 2. Graph showing how the 1306's operat-
ing mode and measurement "frequen-
cy" is dependent on the concentration
ofmonitored gas measured by the 1306

Remote Control
The user controls the 1306 remotely
by sending
commands/requests via
the control station .
Commands
The user can command the 1306 to
perform
any one of a number of mea-
surements or tests, or to change its
mode of operation,
at any time. The
1306 responds by immediately stop-
ping
what it is doing and carrying out
the command. This facility is particu-
larly useful in
alarm situations and
during service and maintenance .
Requests
The 1306 stores the results of its
most recently completed measurement
and self-test sequences. This
data is
continuously updated and can be re-
quested from the 1306
at any time with-
out disturbing its mode of operation.
Communication
A shielded, balanced, two-wire com-
munication cable is used to connect
the 1306 to its control station (com-
puter).
The cable handles communica-
tions
in both directions. A single com-
puter can control up to 31 Toxic-gas
Monitors,
and the total distance be-
tween
the computer and the last 1306
on
the cable can be up to 12 km , de-
pending
on the number of 1306s being
used. Modems
can be used to increase
this distance.
A special procedure (DDCMP)* is
used to check all data transmitted on
the communication cables. This proce-
dure makes it possible to reduce the
data-transmission error-rate almost to
.. Power Supply Unit
177710ther compatible equipment
l.LL..J (e.g. Wind Velocity Monitor .)
RS485
RS 232C
,--1
Control
I I Station
.I.
I
lO
Converter I
co
'<t
RS 485-
I
en
a:
RS 232C I
~
L_
~I
'<11
~I
Self-tests
Frequency
Switch settings; temperature of gas in analysis cell; voltage
supply to the 1306; Lid (to see if 1306 has been opened); A-D every 260
ms
converter
Software; processing system every 18 s
Humidity lamp; temperature of I.R. source; frequency
of
same as gas
chopper measurement frequency
Microphones; preamplifiers; valves; air pump; air-shunt every 30
min.
T01491GBO
Table 1. Self-tests made by the Toxic-gas Monitor
zero. Each 1306 is given its own address
and the DDCMP enables the control
station to communicate individually
with each monitor connected to it.
The control station and the 1306
communicate via
the RS-485 inter-
face.
This interface was chosen in
preference
to the RS-232C interface,
which most computers use, for
three
important reasons: (1) it allows faster
serial transmission of data;
(2) it al-
lows
up to 31 monitors to be connect-
ed in parallel on a single cable to a
single
computer which controls them,
so that if any monitor in this network
stops functioning or is disconnected,
the control station does not lose con-
tact with all the other monitors in the
network (see Fig. 3). The monitors in
this network
can be 1306s or any other
monitors which use the same interface
and protocol, for example wind veloci-
ty/direction monitors; and (3) the RS-
485 interface standard allows a much
greater distance between the comput-
er and the last 1306 on the cable.
A
computer fitted with an RS 232C
interface can be used as a control sta-
tion by using an interface converter in
the monitoring network (see Fig. 3).
* Digital Data Communications Me ss age Pr otocol
developed by Digital Equipment
Co rporation.
Reliability
The Toxic-gas Monitor has been rigor-
ously tested to ensure reliability of per-
formance and results. Performance reli-
ability
is ensured by the comprehensive
series of self-tests which the
1306 contin-
uously performs. See Table 1
for details.
A
status report, which summarises
the results of the 1306's self-tests, is
sent to the control station with all mea-
surement results. The user can therefore
see
at a glance what, if anything, has
affected the accuracy of the measure-
ment; or which fault has caused the
1306 to stop taking gas measurements,
so that appropriate action can easily be
taken to correct the fault.
As soon as
the condition causing the
fault is corrected the 1306 automati-
cally starts up again.
Power Supply
The Toxic-gas Monitor requires a 12 V
DC power supply. This can be obtained
either: from the
AC mains by means of
the Power Supply
ZG 0309 which is pro-
vided as an accessory; or from a
12 V car
battery. A car battery can also be used to
provide power for short-term monitoring
from a stationary vehicle.
Address 29
Type 1306
Power~:!
Supply
Cable
87115211
Fig. 3. A simple monitoring network comprising Toxic-gas Monitors and other compatible equipment
3

The 1306 is provided with an input
filter which protects it from transient
voltage surges on the power supply
caused,
for example, by lightning strikes.
The
1306 resumes its automatic opera-
tion as soon as the voltage supplied to it
falls within operational limits.
Maintenance
Regular maintenance of the 1306 in-
volves calibration
and change of the
All terms relating to gas analysis are in ac-
cordance with the definitions set out in the
ISO Draft International Standard 8158
Details about the optical filters which are
available for use with the 1306 can be found
in the "Optical Fil
ters" Product Data Sheet.
An optical
filter UA XXXX is installed in the
1306, which is then zero-point calibrated be-
fore delivery. Calibration with a
specific gas
is optional. A "calibration
chart " gives details
about the installed optical filter and the ca li-
brat ion of the 1306.
MEASUREMENT TECHNIQUE:
Photoacoustic infra- red detection
RESPONSE TIME:
45s -55s (time taken to purge the cell, and
measure the gas concentration in the new air
sample).
ACCURACY:
Zero Drift:
Typically = Detection Threshold per 3 months•
Influence
of temperature •: insignificant-
compensated
for internally.
Influence
of pressure.&: ± 1, 5% of detection
threshold/mbar
A gas concentration equal to 1% of the maxi-
mum measurable concentration was used in
determining the following specifications
Repeatability: 1% of measured valuee
Range Drift:
± 2,5% of measured value per 3 months•
Influence of temperature• : insignifi cant-
compensated for internally.
Influence
of pressure.&: - 0,01% of measured
value/mbar
MEASUREMENT RANGE:•
Detection Threshold: is gas-dependent but
ranges
from parts/million (ppm) to parts/bil-
lion (see Table for examples of the detection
threshold of some pure gases/vapours).
Dynamic Range: four orders of magnitude
(that is, the upper detection
limit= 10000
times the lower detection limit)
GENERAL:
Cabinet: complies with IEC 529 & IP 53 Stan-
fine air-filter. The frequency with
which these two operations need
to be
performed is dependent on
the 1306's
measurement frequency, and on the
amount of suspended matter (e.g.
dust) in
the air it is monitoring.
The status report informs the
user of when the 1306's fine air-filter
needs to be changed.
It is often practi-
cal to calibrate
the 1306 when its fine
air-filter is changed (typically 4 times
a year). Calibration in
the field (in
Specifications 1306
Gas/Vapour Detection Threshold
(ppm)
Phosgene 0,03
Vinyl chloride 0,2
Ammonia 0,3
Styrene 0,2
Perchloroethylene 0,
05
Ethylene oxide 0,1
Benzene 0,8
Total hydrocarbons
0,1
(with ref . to propane)
T0 1 814GBO
dards. Resistant to rain falling at a maximum
angle of 60 ° to the vertical axis. Dust resistant
Dimensions:
Height: 400 mm (15,7 in)
Width: 200 mm (7,9 in)
Depth: 102 mm (4,0 in)
Weight: 5,5 kg (12,1 lbs)
Operating Temperature: -20°C to +50 °C
Relative Humidity: 95%-100% relative hu-
midity at soo C
Power Requirement:
Power Supply ZG 0309 complies with IEC348
Class 1 Standards. It converts: 90, 100,110,
120,130,200,210,220, 230, 240 VAC ± 10%,
50/60Hz to 12 V DC. Power consumption:
-SOVA . Alternatively, a DC power supply
(e.g. a car battery) providing 12 V (+15%/
-20%) to the input terminals of the 1306 can
be used. The 1306 is supplied with an
at -
tached 4m power cable.
Power Consumption:
During measurements: 34 W peak (start) and 18 W
operating.
On standby: 2W (power-down mode)
Vibration Sensitivity: Strong vibrations
occuring at a frequency of 20 Hz can compro-
mise the detection-threshold specificat ion.
Acoustic Sensitivity: Not influenced by ex-
ternal sound
situ) is performed using a known con-
centration of either the gas to be mon-
itored, or a
substitute gas.
If the 1306 stops taking gas measure-
ments the user can request detailed re-
sults of all the 1306's self-tests. Using
this data, service engineers can quickly
diagnose any fault and perform neces-
sary repairs without
delay. This means
that service costs can be minimised and
that the 1306 is out of operation for the
shortest possible time.
Electromagnetic Compatibility: Comp lies
with U.S. FCC requirements for class B
computing devices.
Electromagnetic Pulse (EMP) Protection: In
accordance with CCITT recommendation K17.
COMMUNICATION:
The 1306's digital interface complies with the
EIA Recommended Standard RS 485. The
Digital Data Communication Message Proto-
col (DDCMP) is used to ensure error-free and
synchronized data transfer. The 1306 is sup-
plied with an attached 4m communication ca-
ble. The Application Diskette BZ5003 provid-
ed allows users to control a single 1306. B& K
Application Software Type 7619 is available
which allows users to control up to 31 Toxic-
gas
Monitors in a network.
ACCESSORIES INCLUDED:
Application Diskettes .
.... .. . .. ... .. ............ BZ 5003
Power Supply ........ ... .. .. .... ....... .. ..... ... . .... ZG 0309
Spare Fine Air-f ilter Thumbscrew
Unit,"
0" -r ing & Retaining Disc ... .. .. . .. .UA 0994
Fine Air-filters (10) . .. .. .. ....... .... ..... ... . .. . .. OS 0714
Coarse Air-filter Unit (2) . ... .. ............. .. .UC 0193
Calibration Kit consisting
of :
Teflon Tubing (4m).................. ...... ....... .. . AT 2177
Calibration Stub. .. ......... .. ... ... .... .. ......... .. DB 3023
"Y"-piece
..... .... ........... ... .... .. .·................. .. UD 5001
"0"-ring (4) . .. ........ .. ..... .. ... ... .... .. ........ . .... . YJ 0770
Threaded Nut... .. . .... .... .. .. ... .. ............... ... . YM 0652
Spare Fuses:
2 x 125
mA . ... .. .. ............ ... .. ... ......... .... . ... .. VF 0030
2 X 2,0 A............................. .. .... ..... .... ... .. .. VF 0010
2 X 4,0 A......... ... .............. ...... .. ....... ... . .... .. VF 0045
Allen Key
to open/close the 1306.... .. QA 0161
Special Key to install optical fil ter ... .. QA 01 62
" C" spanner (wrench) ................... .. ...... QA 01 81
Tweezers ..................... .. ............... .. .... .. ... QA 0164
ACCESSORIES AVAILABLE:
Optical Filters (22)...........
.. .... .UA0968-UA0988
.... ..... .... ... .. .... . .. .... ............ .. .. .. .. ... .. .. ..and UA0936
RS 232C-RS 485 Converter................WQ 0677
Communication Cable with
2 x 25pin connectors......
.... .... ........... ... WL 0814
Communication Cable with a 25-
pin and a 9-pin connector.
.... .. . .. .... .. .. WL 0815
REFERENCE CONDITIONS:
• Measured
at 20 °C, 1013 mbar, and relative
humidity (RH): 60%.
• Measured
at 1013 mbar, and RH : 60%.
.& Measured at 20°C and RH : 60%.
For information on the installation of the Toxic-gas Monitor contact your local Bruel & Kja3r representative.