Servomex 2700 User manual

2700
Combustion Gas Analyser
™
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Servomex 2700 Quickstart Manual
Servomex 2700 Quickstart Manual 1
1. INTRODUCTION
1.1 Warnings, Cautions and Notes
This manual includes WARNINGS, CAUTIONS and NOTES
which provide information relating to the following:
1.2 Scope of this manual
This manual describes the operation of the Servomex 2700
Combustion Gas Analyser and details the various options that
are available.
•For the technical specification, see Section 5 of this
manual.
•For installation details, see the Installation Manual (part
no. 02700005C).
•For servicing details, see the Service Manual (part
no. 02700002C). This is written for use by suitably qualified
personnel.
•For the addresses for technical assistance and spares, see
the rear cover of this manual.
WARNINGS
Hazards which could result in personal injury or death
CAUTIONS
Hazards which could result in damage to equipment
or property
NOTES
Alert the user to pertinent facts and conditions
About this manual
Reference: 02700/003C/3
Order as part number: 02700003C

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1.3 Key to Figures on inside of front cover of this manual
(Figures 3a and 3b can be found at the end of this manual)
CE Marking
The Servomex 2700 analyser carries the CE mark which
indicates conformity with the European Community
Directives on CE Marking (93/68/EEC), Electromagnetic
Compatibility (EMC 89/336/EEC) and Low Voltage Directive
(LVD 73/23/EEC).
Servomex 2700 control units are marked in conformity with
the Explosive Atmospheres (ATEX) Directive (94/9/EC)
when fitted with a European hazardous area certification
marking plate.
Figure 1 Sensor head and control unit
1 Terminal box 6 Control unit
2 Sensor head 7 Wall mounting straps
3 4" mounting flange 8 Display and keypad
4 Sample probe 9 Hinged access door
5 Sample filter
Figure 2 Control unit display and keypad layout
1 LCD with measurement display 5 MEASURE key
2ENTER key 6 QUIT key
3ARROW keys 7 Alternative main
menu display
4MENU key
NOTES
As good practice it is recommended that the analyser is
checked/validated with check gas every month and then
calibrated as required. This period can be extended as a
result of operating experience.

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2. STARTUP AND SHUTDOWN
2.1 Analyser startup
If the sensor head and sample probe have been removed from
the flue, then refit the sensor head and sample probe to the flue
and reconnect any interconnecting wiring (see Installation
Manual).
Switch on the electrical power to the sensor head and to the
control unit.
Leave the unit for two hours to warm up and then check that no
faults are indicated on the control unit display screen.
Connect the aspirator air supply to the sensor head. The correct
operating pressure is stated on a label attached to the inside of
the terminal enclosure on the side of the sensor head.
If necessary, connect calibration gases to the sensor head to
verify correct operation. See Section 3.4 for Calibration
procedure.
CAUTION
If the analyser is to be installed in a low temperature
environment (-20°C) then it should be powered up for a
period of two hours before the compressed air aspirator
supply is applied. This prevents corrosive sample gases
from condensing inside the sensor head pipe work.
NOTES
•The analyser should be allowed to stabilise for several
hours (typically overnight) before calibration.
•It is then recommended that calibration gases be passed
through the sensor head to confirm operation of the
analyser.

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2.2 Analyser shutdown
Attach a dry air supply to the calibration port of the sensor head
and purge the sensor head for 5 minutes at 600 ml/min flow
rate. The aspirator air supply should be left on at this point.
Switch off the aspirator air supply to the sensor head.
Switch off the electrical supply at the control unit and then at the
sensor head.
Leave the sensor head to cool down for a minimum of two
hours.
If the analyser is to be un-powered for more than 1 week then
please note the cautions above.
WARNING
The sensor head is heated and may be attached to a hot
flue. The external surfaces will be uncomfortably hot even
after power down for several hours. Exercise care when
handling the sensor head even when un-powered on a hot
flue.
CAUTION
•The sensor head should always be powered when left on
a flue which is in use. If left un-powered, the sensor head
can suffer corrosion damage.
•If the process is out of service for a short time it is
recommended that the analyser sensor head is left
powered. It is not essential that the aspirator air is left
flowing.
•If the analyser has to be switched off for more than
1 week whilst on a flue which is in use, it is
recommended that a flow of dry air be connected to the
calibration port. Alternatively, the sensor head can be
removed from the flue and a blanking plate fitted. This will
prevent corrosive gases from entering the sensor head.

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3. OPERATION
3.1 Operating the analyser (Refer to Figure 2)
The Servomex 2700 control unit has a tactile 8 button keypad
and back lit LCD (2 lines x 16 characters). During normal use
the LCD will display either the default measurement display or
a menu-based screen editor display. A user can toggle between
the menu display and measurement display and access the
menu-based screen editor using the keypad.
The functions of the keys on the keypad are:
MEASURE Returns the analyser to the measurement display.
MENU Activates the top level menu of the screen editor.
QUIT Aborts the current activity returning the screen
editor to the menu level at which the activity was
selected.
ARROWS Arrow keys select the desired option. When
entering numeric information, the left and right
arrow keys are used to move between digits and
the up and down arrow keys are used to change the
value of each digit. The active digit is highlighted by
blinking. The user presses the 'ENTER' key to
indicate that the numeric input is complete and the
data is to be saved. If the 'QUIT' key is pressed then
the data is not saved and the input is aborted.
Measurement display - Scrolls through alarm
and/or fault messages.
ENTER Indicates that the menu selection is to be
processed or that numerical input is complete.
To initiate any menu operation the MENU key should be
pressed. The LCD will then present the top level menu, which in
turn leads on to other menus.
At each menu, the user highlights the desired option using the
arrow keys and then presses ENTER. Blinking is used to
highlight the selected menu option. During any menu operation,
the fundamental measurements are still being made by the
analyser and all relevant outputs, alarms and diagnostics
remain active.

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The measurement display is shown in Figure 2. The top line of
the display shows the current measured value (with its units) for
each of the sensors fitted.
In normal operation the bottom line of the display labels the
gases measured. Should a fault or alarm occur then the lower
line of the display will detail the nature of the fault or alarm.
Should more than one fault and/or alarm be active then arrow
keys on the keypad may be used to scroll through these
messages.
The fault messages that may appear are as follows:
OXYGEN LOW Oxygen too low for reliable COe
measurement
OXYGEN °C LOW Oxygen sensor temperature too low
OXYGEN °C HIGH Oxygen sensor temperature too high
COe mV LOW Combustibles sensor output voltage
low
COe mV HIGH Combustibles sensor output voltage
high
COe °C LOW Combustibles sensor temperature too
low
COe °C HIGH Combustibles sensor temperature too
high
SENSOR °C HIGH Sensor head temperature too high
(OPTIONAL)
SENSOR °C LOW Sensor head temperature too low
(OPTIONAL)
AUTO CAL FAIL Autocalibration out of tolerance error
COe mV OUTPUT LOW Combustibles sensor sensitivity low
(updated after calibration only)
COe CONC HI Combustibles sensor has been
exposed to very high Coe levels
mV
OUT OF TOLERANCE Combustibles sensor mV greater than
+/-60mV
DISPLAY OVER RANGE Measurement is too large to display
COe WARMING Combustibles sensor is warming up
O2WARMING Oxygen sensor warming up
The MEASURE key may be used to return to the measurement
display at any time.

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3.2 View/Configure functions (Refer to Figures 3a & 3b)
The view functions allow the user to interrogate the analyser
diagnostics and examine the alarm and fault history logs. No
password is required to access the view functions. The view
functions are updated dynamically and values may change
while they are being viewed. To access this display, press the
MENU key and then select VIEW. If the DIAGNOSTICS option
is chosen, the diagnostics appear as a scrolling list of values
and associated descriptions. There are up to ten diagnostics
depending on which sensors are fitted.
The ↑ ↓ keys are used to switch between the following
diagnostic measurements:
Software version
Oxygen sensor output voltage in mV
Oxygen sensor temperature in °C
Oxygen high calibration point in mV
Oxygen low calibration point in mV
Combustibles sensor output voltage in mV
Combustibles sensor temperature in °C
Combustibles high calibration point in mV
Combustibles low calibration point in mV
(Negative values are unfiltered and will differ from those
displayed at top level)
Probe head temperature in °C (if connected)
If the HISTORY option is chosen, either the alarm or fault history
logs can be examined. The ↑ ↓ keys are used to scroll through
the list of history entries in chronological order.
The configure function allows the user to modify and view the
analyser settings. These functions are password protected. To
access these functions, press the MENU key, select
CONFIGURE and then enter a password. There are two
passwords that can be entered; a supervisor password
(default - 2700) which gives access to CALIBRATE, VIEW,
SERVICE & SETUP and an operator password (default - 2000)
which gives access to CALIBRATE and VIEW only. Both
passwords are factory set and may be changed if required.

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3.3 Analyser setup (Refer to Figures 3a and 3b)
The setup function allows the user to modify and view the
analyser configuration (outputs, alarms, blowback, clock and
passwords).
3.3.1 Setting up the concentration alarms
The control unit has 2 concentration alarms that can be
assigned to either of the 2 possible sensors in the sensor head.
Each concentration has a user configurable level, hysteresis
and polarity (high or low alarm).
Each alarm may also be configured to either freeze (remain
fixed at the last value) or follow (track the concentration
changes) during analyser calibration.
The setup process is as follows:
1. Press the MENU key, then select CONFIGURE, enter a
valid password, select SETUP and then ASSIGN.
2. Select ALARMS to set up the concentration alarms.
3. Select AL1 or AL2 to specify which alarm is to be set up.
4. Select either NONE, OXYGEN or COe to disable the alarm
or to specify the measurement to be the subject of the
alarm.
5. Select either FREEZE or FOLLOW to specify if the alarm is
to be fixed at its current value or to track the concentration
during analyser calibration.
6. Select either LOW or HIGH to specify the alarm as a low
alarm or a high alarm.
7. Use the arrow keys followed by the ENTER key to set the
concentration level at which the alarm is to be triggered.
8. Use the arrow keys followed by the ENTER key to set the
hysteresis on the alarm level.
The alarm assignment is now complete and the user is returned
to the select alarms display (step 3 above) to allow other alarms
to be configured. Use the QUIT or MEASURE key to return to
the assign menu or the measure display as required.

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3.3.2 Setting up the relay outputs
The Servomex 2700 analyser is supplied with 4 relay outputs
that can be assigned to a number of outputs. Output options
include concentration alarms, analyser fault, calibration in
progress, blowback in progress, autocalibration solenoid valve
control lines and blowback solenoid valve control line.
Default relay assignments are: Relay 1 is concentration
alarm (AL1), Relay 2 is concentration alarm (AL2), Relay 3 is
Analyser Fault (AF) and Relay 4 is the 'IN CALIBRATION'
message. The default assignments can be changed as follows:
1. Press the MENU key, then select CONFIGURE, enter a
valid password, select SETUP and then ASSIGN.
2. Select RELAYS to set up relay outputs.
3. Select 1, 2, 3or 4for the relevant relay number.
4. The available assignments are presented as a scrolling list.
Use the ↑or ↓keys to select the required assignment and
then press the ENTER key.
The possible relay assignments are:
ALARM 1 Concentration alarm AL1
ALARM 2 Concentration alarm AL2
FAULTS Analyser fault present AF
IN CALIBRATION Calibration in progress
IN BLOWBACK Blowback in progress
GAS 1 Autocalibration gas 1 solenoid valve
GAS 2 Autocalibration gas 2 solenoid valve
GAS 3 Autocalibration gas 3 solenoid valve
BLOWBACK AIR Blowback air solenoid valve
5. The display is returned to the relay number select screen to
allow other relays to be assigned. Use the QUIT or
MEASURE keys to return to the assign menu or
measurement display as required.

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3.3.3 Setting up the analogue outputs
The Servomex 2700 is supplied with one dedicated analogue
output for each sensor fitted in the sensor head (maximum of
2 analogue outputs). Each analogue output has a minimum and
maximum analogue output range.
For the oxygen sensor, 0-1% is the minimum range and 0-25%
is the maximum. For a 1750702 combustibles sensor,
0-500ppm is the minimum range and 0-30000ppm is the
maximum.
Each analogue output can be configured as either 0-20mA or
4-20mA and to either freeze (remain at the last value) or follow
(track the concentration changes) during calibration and
blowback. The 20mA high point is limited to an over-range of
20.5mA during normal operation. If 4-20mA is selected, then
this can also be configured to under-range that can be set down
to 3.6mA in 0.1mA increments.
An optional "Jam" facility is available to allow the output to set
to 0mA (LOW) or 21mA (HIGH) when an analyser fault is
detected. The outputs are capped so that their value can not
exceed 21mA. The setup process is as follows:
1. Press the MENU key, then select CONFIGURE, enter the
supervisor password, select SETUP and then ASSIGN.
2. Select mA OUTPUTS to set up the analogue outputs.
3. If two sensors are fitted then the analyser will prompt the
user to select the output to be configured. Select either
OXYGEN or COe to specify the output dedicated to the
oxygen sensor or combustibles sensor as required.
4. Select the measuring range required, then ENTER.
5. Select either FREEZE (to freeze the output at the last
value) or FOLLOW (to follow concentration changes during
calibration or blowback).
6. Select either 4-20mA or 0-20mA for the analogue output
type.
7. If 4-20mA is selected, set the low limit desired.
8. Select either LOW, HIGH or NONE to specify whether the
output should be fixed at 0mA (LOW), 21mA (HIGH) or be
unaffected should an analyser fault occur.
The analogue output configuration is now complete. The user is
returned to the sensor selection display (step 3 above) to allow

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other analogue outputs to be configured. Use the QUIT or
MEASURE keys to return to the assign menu or measurement
display as required.
3.3.4 Setting up a blowback process
The blowback procedure allows the user to apply a burst of a
selected gas to the calibration port of the analyser to back flush
the sample probe and filter. The blowback gas is controlled via
a solenoid valve switched by one of the relay outputs. The
required relay output must be assigned before starting a
blowback operation. The blowback setup will include a start
time and date, a time period between blowback processes, and
a duration for the blowback process.
A blowback operation may be executed by one of the following
means:
1. By timer when the indicated start time and date is reached.
2. By external contact closure between pins 13 and 14 on
terminal block TB2 on control unit PCB.
3. From the keypad using the START BLOWBACK entry in
the setup blowback menu. The supervisor password will be
required and a relay output must be assigned to blowback.
If a start date and time is not set then the blowback can only be
initiated by contact closure or from the keypad. If the period
between blowback processes is set to zero then only a single
timed blowback will be executed. The process for setting the
blowback parameters is as follows:
1. Press the MENU key, then select CONFIGURE, enter a
valid password, select SETUP and then BLOWBACK.
2. Select SET UP BLOWBACK to set the blowback
parameters.
3. Use the arrow keys to define the duration in minutes (MM)
and seconds (SS) of the blowback. Use the ENTER key to
save the value.
4. Use the arrow keys to define the period in days and hours,
between successive blowback processes. Use the ENTER
key to save the value.

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5. Use the arrow keys to define the start date for the first
blowback. The format will be either day/month/year
(DDMMYY) or month/day/year (MMDDYY) as defined in
the setup clock procedure (see Section 3.3.5).
Use the ENTER key to save the value.
6. Use the arrow keys to define the start time for the first
blowback. Use the ENTER key to save the value.
Successive blowback operations will start at the time and
frequency previously set.
3.3.5 Setting up the real time clock and date format
The process for changing the time, date and the date display
format is as follows:
1. Press the MENU key, then select CONFIGURE, enter a
valid password, select SETUP and then UTILITY.
2. Select CLOCK to change the time and date.
3. The current time and date will be shown on the display for 4
seconds before proceeding. Select YES to continue
changing the time/date or NO to return to the utility menu.
4. Use the arrow keys to define the new date. The date will be
specified either as day/month/year (DDMMYY) or
month/day/year (MMDDYY). Press the ENTER key to save
the new date.
5. Use the arrow keys to define the new time. The format is
hours:minutes (HH:MM).
6. Select either DDMMYY or MMDDYY to specify if dates are
to be displayed in day/month/year or month/day/year
format.
7. The new time and date will be displayed in the selected
format for 4 seconds before returning to the utility menu.
NOTE
After completion of the BLOWBACK process, if FREEZE
has also been selected the analogue outputs remain at
freeze and display shows ‘flushing’ for a fixed period of
120 seconds.

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3.3.6 Setting a new password
Both passwords are factory set and can be changed as follows:
1. Press the MENU key, then select CONFIGURE, enter a
valid password, select SETUP and then UTILITY.
2. Select PASSWORD to change the passwords.
3. Select either SUPERVISOR (default - 2700) or
OPERATOR (default - 2000) to define which password is to
be changed.
4. Use the arrow keys to set a new 4 digit password. Use the
ENTER key to save the new password.
5. The new password will be repeated by the analyser. Select
either YES or NO to accept or reject the new password
value.
3.3.7 Setting the auxiliary air option
The auxiliary air is intergrated into the sensor head and
therefore this feature must always be set to YES when the
combustibles sensor is used
1. Press the MENU key, then select CONFIGURE, enter a vaid
password, select SETUP and then UTILITY.
2. Selet AUX AIR to set the auxiliary air status.
3. Select either YES or No to indicate if auxiliary air is applied to
sensor head or not.
3.4 Calibration (Refer to Figures 3a & 3b)
The operator/supervisor passwords are required to access the
calibration functions. The user may either perform a manual
calibration, set up the automatic calibration parameters or
execute an automatic calibration. Servomex recommend that
the oxygen sensor is calibrated every three months and the
combustibles sensor every one month. In some applications the
calibration interval may be extended as a result of operating
experience.
During manual calibration, a LOW calibration must be
made prior to a HIGH calibration for the combustibles
sensor.

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3.4.1 Manual calibration procedure
1. Press the MENU key, then select CONFIGURE, enter a
valid password and then select CALIBRATE.
2. If two sensors are fitted in the sensor head then select
either OXYGEN or COe for the sensor to be calibrated.
3. Select LOW CAL or HIGH CAL for a low calibration or high
calibration measurement. The procedure for performing the
low or high calibration of an OXYGEN or COe sensor are
the same.
4. Use the arrow keys to set the actual concentration value for
the calibration gas used. Press the ENTER key to accept
the value.
5. Use the arrow keys to set the required tolerance level.
This is the permitted change in the stored calibration value.
Press the ENTER key to accept the value.
6. Apply the calibration gas to the sensor head calibration port
at a flow of 600ml/min. Note: if autocalibration is selected
then the relay outputs will be automatically set to admit the
required calibration gas.
7. Wait until the value displayed on the screen is stable.
Select Yand the ENTER key to accept the measured
value. Note: the displayed value will be calculated using the
existing stored calibration value.
8. Should the user accept a value that is outside of the
tolerance limits an OUT OF TOLERANCE message will be
NOTE
1. When a low calibration is performed, the zero may be
offset between the limits of -500 and +99ppm which
enables the effects of non-CO combustibles to be
compensated for. If this is done, the span calibration
target value should be adjusted by the same amount in
order to maintain accuracy. E.g. if the zero is adjusted by
-50ppm then the span should be set to 450ppm when
using a 500ppm CO calibration gas.
2. In calibration mode negative ppm combustibles values
are unfiltered and will differ from those displayed at top
level.