Novatech CONTROLS 1738 User manual

Dew Point Transmitter
Model 1738
Operators Manual
January 2020

January 2020 Operators Manual
1738 Dew Point Transmitter 1
TABLE OF CONTENTS
1. USING THIS MANUAL.................................................................................................................................. 3
1.1 CAUTIONS.................................................................................................................................................. 3
1.2 WARNING SYMBOLS.................................................................................................................................... 4
2. INTRODUCTION ........................................................................................................................................... 5
3. SPECIFICATIONS......................................................................................................................................... 7
3.1 HARDWARE SPECIFICATIONS....................................................................................................................... 7
3.2 OPERATIONAL SPECIFICATIONS................................................................................................................... 8
4. DISPLAY AND KEYPAD .............................................................................................................................. 9
4.1 RUN MODE DISPLAY................................................................................................................................... 9
4.2 TOP LINE DISPLAY.................................................................................................................................... 10
4.3 KEYPAD ................................................................................................................................................... 10
4.3.1 KEYPAD IN RUN MODE ...................................................................................................................... 10
4.3.2KEYPAD IN SETUP MODE.................................................................................................................... 12
4.3.3 INFORMATION SCREEN....................................................................................................................... 12
5. SETUP MENU ............................................................................................................................................. 13
5.1 SETUP MODE FUNCTION SUMMARY........................................................................................................... 13
5.2 SETUP MODE DETAILS.............................................................................................................................. 13
5.3 SETUP MENU FUNCTIONS ......................................................................................................................... 14
5.3.1 PROBE 1&PROBE 2OFFSET............................................................................................................. 14
5.3.2 LOWER LINE ITEMS ............................................................................................................................ 14
5.3.3 OXYGEN DISPLAY UNITS .................................................................................................................... 15
5.3.4 DAMPING FACTOR.............................................................................................................................. 15
5.3.5 PROCESS ALARMS............................................................................................................................. 15
6. ALARMS ..................................................................................................................................................... 17
6.1 CHECKING AND ACCEPTING AN ALARM....................................................................................................... 18
6.1.1 CURRENT ALARMS............................................................................................................................. 18
6.1.2 ALARM LOG....................................................................................................................................... 19
6.2 ALARM RELAYS ........................................................................................................................................ 19
6.3 COMMON ALARMS .................................................................................................................................... 19
6.4 SELECTABLE PROCESS ALARMS................................................................................................................ 21
6.5 WARNING MESSAGES ............................................................................................................................... 21
7. GAS CALIBRATE AND PURGE ................................................................................................................ 23
7.1 ACTIONS THAT OCCUR WHEN THE GAS SOLENOID KEYS ARE PRESSED....................................................... 24
8. INDEX.......................................................................................................................................................... 25

Operators Manual January 2020
21738 Dew Point Transmitter
©
Copyright NOVATECH CONTROLS PTY LTD —2020
This manual describes the transmitter firmware version 1.11, 03 January 2020
Neither the whole nor any part of the information contained in, or the product described in, this manual may
be adapted or reproduced in any material form except with the prior written approval of Novatech Controls
Pty Ltd (Novatech).
The product described in this manual and products for use with it are subject to continuous developments
and improvement. All information of a technical nature and particulars of the product and its use (including
the information in this manual) are given by Novatech in good faith. However, it is acknowledged that there
may be errors or omissions in this manual. A list of details of any amendments or revisions to this manual
can be obtained upon request from Novatech Controls Technical Enquiries. Novatech Controls welcome
comments and suggestions relating to the product and this manual.
All correspondence should be addressed to: -
Technical Enquiries
Novatech Controls Pty Ltd
309 Reserve Road, Tel: [phone]
Cheltenham Fax: [phone]
Victoria 3192 Email: [email protected]m.au
Australia Web site: http://www.novatech.com.au/
Novatech Controls or their authorised dealers should carry out all maintenance and service on the product.
Novatech Controls can accept no liability whatsoever for any loss or damage caused by service or
maintenance by unauthorised personnel. This manual is intended only to assist the reader in the use of the
product, and therefore Novatech Controls shall not be liable for any loss or damage whatsoever arising from
the use of any information or particulars in, or any error or omission in, this manual, or any incorrect use of
the product.

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1738 Dew Point Transmitter 3
1. USING THIS MANUAL
This manual is a shortened version of the 1738 Dew Point Transmitter product manual to be used by the
operator. It does not cover the commissioning, calibration or servicing of the 1738 Dew Point Transmitter. If
more detailed information is required than what is provided in this manual please refer to the more detailed
1738 Dew Point Transmitter Technical Manual. Both manuals are supplied with each transmitter and are
also available at the Novatech Controls website.
https://www.novatech.com.au/products/1738
It is assumed in this manual that the transmitter has been installed by competent personal and that the wiring
to the main power supply, the oxygen probe and all the associated signal devices complies with the local
safety codes and regulations.
1.1 Cautions
Please read the safety information below before connecting power to the transmitter.
CAUTION 1
The probe heater is supplied with mains voltage. This supply has electrical shock danger to maintenance
personnel. Always isolate the transmitter before working with the probe.
The EARTH wire (green) from a heated probe must ALWAYS be connected to earth.
CAUTION 2
Combustion or atmosphere control systems can be dangerous. Burners must be mechanically set up so that
in the worst case of equipment failure, the system cannot generate explosive atmospheres. This danger is
normally avoided with flue gas trim systems by adjustment so that in the case of failure the appliance will not
generate CO in excess of 400 ppm in the flue. The CO level in the flue should be measured with a separate
CO instrument, normally an infrared or fuel cell type.
CAUTION 3
The oxygen probe is heated to over 700°C/1290°F and is a source of ignition. Since raw fuel leaks can
occur during burner shutdown, the transmitter has an interlocking relay that removes power from the probe
heater when the main fuel shut-off valve power is off. If this configuration does not suit or if it is possible for
raw fuel to come into contact with a hot oxygen probe then the Model 1738 transmitter with a heated probe
will not be safe in your application.
An unheated probe can be utilised in such applications, however the oxygen readings are valid only above
650°C/1200°F.
CAUTION 4
The reducing oxygen signal from the transmitter and the associated alarm relay can be used as an explosive
warning or trip. This measurement assumes complete combustion. If incomplete combustion is possible
then this signal will read less reducing and should not be used as an alarm or trip. A true excess
combustibles analyser, normally incorporating a catalyst or thermal conductivity bridge, would be more
appropriate where incomplete combustion is possible.
Also read the probe electrical shock caution in the probe heater interlock caution in chapter 4.7 of the Model
1738 Technical Manual.
CAUTION 5
FIL-3 filter. If the optional FIL-3 has been fitted to the 1231 probe in this installation, please read the
Important Notice in the Technical Manual.

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41738 Dew Point Transmitter
1.2 Warning Symbols
Danger, high voltage. Risk of electrical shock.
Caution hot surface.
Caution, risk of danger. See additional information
in the manual.

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1738 Dew Point Transmitter 5
2. INTRODUCTION
The Novatech 1738 Dew Point Transmitter provides in-situ measurement for one or two oxygen probes in
annealing and other furnaces with protective atmospheres of hydrogen / nitrogen. The transmitter provides
local indication of oxygen and dew point as well as several other process related variables.
The 1738 Dew Point Transmitter is the direct replacement for the superseded model 1638 transmitter. It
includes a number of hardware and software improvements such as a graphic display, larger characters,
faster microprocessor, simplified set up menu, alarm logging, faster probe heater control and more
calculated values such as burner efficiency.
The 1738 Dew Point Transmitter has a variety of user-selectable functions. They are simple to use because
each selection is menu driven. For options you are not sure about, read the manual on that particular item in
chapter 5. Setup Menu.
Features include:-
Inputs
Two zirconia oxygen probe, heated or unheated
Oxygen range from 1 x 10-30 to 100%
Furnace, kiln or flue thermocouple, field selectable as type K, J, R or S
Main flame established safety interlock (for heated probes only)
Purge flow switch
Outputs
Two linearized 4-20mA or 0-20mA DC isolated outputs, max. load 1000
The output function and the range are field selectable
Common alarm relay (programmable)
Three other alarm relays with selectable functions
Computer
RS 232-C or RS 485 for connection of a computer terminal or printer for diagnostics of the transmitter, probe
or combustion process. This connection is suitable for network connection to a computer, DCS or PLC using
MODBUSprotocol.
Display
Multi font graphical display
Large characters for the oxygen on the top line
Multiple lower line items for the secondary functions. ie Probe temperature, % Oxygen for the second probe
Alarm display mode that shows the time the alarm occurred and the acceptance time
Alarm log mode that keeps the time the alarm occurred, the acceptance time and the time the alarm was
cleared for the last 4,000 alarms
Power
Universal mains supply voltage, 100 to 240VAC
Automatically detects the mains voltage and frequency and set the power control accordingly

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3. SPECIFICATIONS
3.1 Hardware Specifications
Number of oxygen probes: 1 or 2
Oxygen range: 1 x 10-30 to 100%
Dew Point range -60°C to 40°C
Pre Reactive Oxygen range 0 to 10%
Oxygen Accuracy: ±1% of actual measured oxygen value with a repeatability of
±0.5% of the measured value
Thermocouple types: Type K, J, R and S
Temperature accuracy: ±2°C
Analog outputs: 0-20mA or 4-20mA field selectable
Active Outputs
(WARNING: DO NOT LOOP POWER OUTPUTS. Use only passive receivers for commissioning and
testing. The use of loop powered receivers will damage the output)
Analog output load: 1000 ohm max
Alarm relays: 4
Alarm relay contacts: 2Amp 240VAC, 2A 30VDC
(WARNING: Do not use both mains voltage and low voltage connections to adjacent alarm contacts)
Mains voltage supply: 100 to 240VAC, 50/60 Hz
Reinforced Insulation
Overvoltage: Category II (IEC60364-4-443)
Power: 5 Watts for controller plus probe power
530W max., 25% duty cycle each probe on 240VAC
110W max., 100% duty cycle each probe on 110VAC
576W (2.4A) max
Environmental Rating: Operating Temperature -25°C to 55°C
Relative Humidity 5% to 95% (non-condensing)
Altitude: 2000m Maximum
Degree of Protection: IP65
IP54 with internal reference air pump
Case Size: 315mm (12.4”) wide, 190mm (7.5”) high, 110mm (4.3”) deep
Case Weight: 3.3 Kg (7.3 lbs.)
WARNING: All signal level connections onto the transmitter must be treated as safety extra-low
voltage (SELV) as defined in the standard IEC61140. Double insulation must be used when
connecting these terminals to systems that might carry high voltage.

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81738 Dew Point Transmitter
3.2 Operational Specifications
Range of Analog Outputs: Field selectable from the following:
Function
Min Range
Max Range
Probe 1 or 2 Dew Point
20°C
-60°C to 40°C
Average Dew Point **
20°C
-60°C to 40°C
Probe 1 or 2 Linear Oxygen
1%
0 to 100%
Average Oxygen **
1%
0 to 100%
Probe 1 or 2 Reducing Oxygen
2 decades
1x10-30% to 100%
Average Reducing Oxygen
2 decades
1x10-30% to 100%
Probe 1 or 2 Pre-Reactive Oxygen
1%
0 to 10%
Average Pre-Reactive Oxygen
1%
0 to 10%
Probe 1 or 2 EMF
100mV
0 to 1300mV
Aux TC Temperature
100°C
0 to 1400°C
No Output
Output 1 transmits process variables for Probe 1, Output 2 transmits process variables for Probe 2 if
enabled, otherwise Probe 1. Output ranges for averaged process variables are only available when
transmitter is configured with two probes are enabled.
Local Display, Top Line Selectable from the following:
Range
Probe 1 Dew Point
-60°C to 100°C
Probe 1 Pre-Reactive Oxygen
0 to 10.0%
Probe 1 Oxygen
1x10-30 to 100%
Local Display, Secondary Functions:
Process Variable
Range
Probe 1 Dew Point
-60°C to 100°C
Probe 2 Dew Point **
Average Dew Point **
Probe 1 TC Temp
Up to 1760°C/3200°F
Probe 2 TC Temp **
Probe 1 EMF
-30 to 1350mV
Probe 2 EMF **
Probe 1 Impedance
0 to 300k Ω
Probe 2 Impedance **
Probe 1 Oxygen %
1x10-30 to 100%
Probe 2 Oxygen % **
Average Oxygen % **
Probe 1 Pre-Reactive Oxygen
0 to 10.0%
Probe 2 Pre-Reactive Oxygen **
Average Pre-Reactive Oxygen **
Auxiliary TC Temp
Up to 1760°C/3200°F
Ambient Temperature
0 to 70°C
Ambient RH%
5 to 95%
Flue Pressure
varies
Runtime
Service Date
4-20mA Output 1
0 to 24.0mA
4-20mA Output 2
** Process variables for second probe or averaging of two probes are only available when the transmitter is
configured with two probes enabled.

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1738 Dew Point Transmitter 9
4. DISPLAY AND KEYPAD
The 1738 Dew Point Transmitter has a graphic display, 8 buttons and 5 LED indicators to show the status of
the transmitter.
All of the buttons have multiple functions, depending on what is currently on the display. As a general
starting point, the larger white text on the button is the function while the transmitter is in the Run Mode and
the smaller black text on the button is the function in the Setup Menu.
When the transmitter is sitting idle it will revert to Run Mode, in which standard information relating to the
process appears on the screen. In order to configure the transmitter the operator must access Setup Menu.
This is achieved by pressing the SETUP button. The transmitter will return back to the Run Mode when the
SETUP button is pressed again or after a period of 60 seconds of inactivity.
The front panel of the 1738 Dew Point Transmitter
4.1 Run Mode Display
In Run Mode the 1738 shows the primary process variable in large characters at the top of the display and a
user selectable lower line in smaller characters below. Other items on the display include the activity
heartbeat indicator in the top-right corner, a row of single letter action indicators in the bottom left corner and
the current time in the bottom right corner.
-18.8c
Probe 1 Temp 720.3 C
B 14:20:36
DP
Power Indicator
Activity Information Indicators:
BBurner input enabled (terminals 11&12)
ATransmitter is performing an automatic
calibration
T(flashing) one or more oxygen probes is below
operating temperature (650°C / 1200°F)
ZTransmitter is performing a probe impedance
check
Heartbeat Indicator
Primary process variable
indicator:
DP Dew Point
PO2Pre-Reactive Oxygen
O2Oxygen
Top line primary
process variable
Lower line secondary
process variable
Current time

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10 1738 Dew Point Transmitter
4.2 Top Line Display
The top line of the display shows the primary process variable in large text. The primary process variable is
selected using the Configuration Menu as described in the Technical Manual. Primary process variable can
be one of the following options;
Dew Point (DP)
Pre-Reactive Oxygen (PO2)
Oxygen (O2)
4.3 Keypad
There are 8 buttons built into the label on front panel of the 1738 Dew Point Transmitter. The button
functions are written in BLACK and WHITE to identify the function of the button in either Run Mode or the
Setup Menu system.
Button Text
Run Mode (white text)
Setup Menu (black/blue text)
1
SETUP /RUN
Enter Setup Menu
Return to Run Mode
2
DISPLAY /FUNCTION 
DISPLAY NEXT LOWER LINE ITEM
NEXT FUNCTION
3
DISPLAY /FUNCTION 
Display last Lower line Item
Previous function
4
ALARM /OPTION 
Next alarm
Next / increment option
5
ALARM /OPTION 
Previous alarm
Previous / decrement option
6
ALARM ACCEPT /ENTER
Acknowledge displayed alarm
Save current option
7
GAS 1PURGE 1/SENS IMP
Gas 1 / Purge 1 manual
activate
Check Probe impedance
8
GAS 2PURGE 2/AUTO CAL
Gas 2 / Purge 2 manual
activate
Manually perform device
calibration
4.3.1 Keypad in RUN Mode
When the transmitter is powered on and has completed the initial startup procedure it will enter the Run
Mode. In this mode the top line of the display will show the primary process variable from probe 1. The
other key functions are –
SETUP /RUN
By pressing this button once from Run Mode the transmitter will enter the Setup Menu system. In the Setup
Menu the function of each of the buttons is reassigned. Pressing the SETUP /RUN button a second time
while in the Setup Menu will return the transmitter to the Run Mode. If the transmitter is left idle in the Setup
Menu for more than 60 seconds it will automatically return to Run Mode.
DISPLAY /DISPLAY 
The display buttons are used to scroll the lower line up and down through the variety of measurements that
are available on the lower line. For a complete list of options see chapter 5.3.2 Lower Line Items
Setup Light
Alarm Light
Cal / Purge Lights
1
2
3
1
4
5
6
8
7

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1738 Dew Point Transmitter 11
ALARM 
If there is either a new alarm or an active alarm the ALARM button can be pressed to examine the alarm
status. The Alarm Light will be flashing if there is a new alarm or steady if there is an existing alarm. (see
Chapter 6. Alarms). The Setup Light will flash slowly to show that the transmitter is now in the alarm display
mode.
ALARM 
When the transmitter is displaying active alarms (the ALARM button has been pressed), the ALARM button
and ALARM button allow the operator to examine the date / time of the alarm and the date / time that the
alarm was acknowledged.
ALARM ACCEPT
Press this button to acknowledge the currently displayed alarm (see Chapter 6. Alarms).
GAS 1/PURGE 1GAS 2/PURGE 2
These two buttons are used to turn on the gas / purge solenoids. When the transmitter is in the manual cal /
purge mode (Commissioning Menu function #23/32) the solenoid will be activated for as long as the button is
pressed. When the transmitter is in the auto cal / purge mode the automatic cal / purge cycle is started. The
cycle can be stopped by pressing the same button again. (see Chapter
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Operators Manual January 2020
12 1738 Dew Point Transmitter
7. Gas Calibrate and Purge)
4.3.2 Keypad in Setup Mode
From Run Mode, if the SETUP /RUN button is pressed once, the transmitter will display the Setup Menu. For
information about accessing the Commissioning Menu or Calibration Menu see the 1738 Technical Manual.
The following functions are then available in the Setup Menu.
SETUP /RUN
Pressing this button while in the Setup Menu will return the transmitter to the Run Mode.
FUNCTION /FUNCTION 
These two buttons allow the selection of the Setup Menu function. A function summary table is found at the
start of Chapter 5. Setup Menu
OPTION /OPTION 
These two buttons allow for modifying the option for the selected function. A list/range of options for each
function is found in Chapter 5.3 Setup Menu Functions
ENTER
This button applies/updates the currently displayed option and stores the value in non-volatile memory to be
retrieved on device start up. If this button is not pressed before changing to a new function then the previous
option will be retained.
SENS IMP
When this button is pressed the transmitter will measure the impedance of oxygen probe(s) attached to the
transmitter. If the burner is not enabled (terminals 10 & 11) or the probe temperature is below 700°C
(1292°F) impedance checking will not be performed. During impedance checking a ‘Z’ will be seen in the
bottom left hand corner of the display.
AUTO CAL
When this button is pressed the transmitter will calibrate the analog output channels that are set to auto
calibration. This is performed by directing the output current away from the output terminals (terminals 12
&13 and 14 & 15) and back the current back into the transmitter input. The transmitter will then calculate a
zero and a span calibration factor for each of the output channels. The output calibration will only happen if
the channel is not set to manual output calibration. (see 1738 Technical Manual for more details)
During this process normal output to the analog channels will be interrupted sending the outputs open circuit.
4.3.3 Information Screen
The 1738 Dew Point Transmitter has an information screen available to the user to allow more detailed
information about the running of the transmitter to be easily read by the user.
The information available is:
1. Model and version of the current firmware
2. The date/time that the firmware was compiled
3. The maximum temperature that the transmitter has measured inside the cabinet
4. Current date and time
5. The time of all the next timed events (Impedance test, cal/purge 1, cal/purge 2)
6. ADC calibration data (analogue input calibration)
7. DAC calibration data (analogue output calibration)
8. Probe temperature record (probe 1 and 2)
The information screen is accessed from the Run Mode by pressing and holding the ALARM ACCEPT button
and then pressing the SETUP /RUN button. The first data appears at the top of the screen and there is a
scroll bar down the left hand side. The data can be scrolled through by using the DISPLAY and DISPLAY 
buttons. The data is for reference only and cannot be changed.

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1738 Dew Point Transmitter 13
5. SETUP MENU
This chapter describes the functions available in the Setup Menu on the 1738 Dew Point Transmitter.
The Setup Menu is mode is accessed from Run Mode by pressing the SETUP button momentarily so the
words ‘Setup Menu’ appear at the bottom of the display. The transmitter will return to the Run Mode when
the SETUP button is pressed again or after 60 seconds of keypad inactivity.
5.1 Setup Mode Function Summary
When the transmitter is in the Setup Menu the SETUP light will be on. The following table shows the Setup
Menu functions:
Menu
Function Description
Range
Default Value
01
Probe 1 offset
±6.0mV
0.0mV
02
Probe 2 offset
±6.0mV
0.0mV
03
Lower line items
See chapter 5.3.2 Lower Line Items
04
Oxygen display units
Oxygen % / Oxygen ppm
Oxygen%
05
Damping factor
No Damping to
10 samples averaged
5 samples averaged
06
Process alarms
Enabled / Disabled
Disabled
5.2 Setup Mode Details
The purpose of having an interactive Setup Menu is to allow for configuration of the transmitter using the
graphical display and keypad.
Once an option is changed and entered using the ENTER button that value immediately becomes active. The
device configuration and calibration is stored into the non-volatile memory and will be retained permanently
even if the device does not have power.
To change an option in the Setup Menu system:
1. Enter the Setup Menu by pressing the SETUP /RUN button once. The Setup Light will come on and
the display will have the format shown below. The operations of the buttons are now the operations
written in WHITE on the keypad. The menu name is written at the bottom of the display.
2. While in the Setup Menu the required function can be selected by using the FUNCTION and
FUNCTION buttons. The options available for that function can be seen by using the OPTION and
OPTION buttons.
3. When the required option is on the display press the ENTER button to save that value.
When finished, press the SETUP /RUN button to return to the Run Mode.
01
Probe 1 Offset
+0.0 mV
Saved
Setup Menu
Power indicator
Menu Number
Selected Option
Activity Indicator:
A Autocal active
ZProbe impedance
check active
Function Name
Verification that the
selected option has
been saved
Menu name

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14 1738 Dew Point Transmitter
5.3 Setup Menu Functions
5.3.1 Probe 1 & Probe 2 Offset
Options: ±6.0mV in 0.1mV increments
Default: 0.0mV
Each Novatech oxygen probe has an offset calibration value printed on a tag that is attached to the probe
when it is dispatched. To achieve the most accurate measurement of oxygen the offset value must be
entered into this setup function with the same polarity as it is printed on the label. For a healthy probe the
offset value should be within ±1.0mV.
NOTE: An offset of 1.0mV will change the oxygen reading by approximately 1% oxygen when the probe is in
ambient air. However, as the process oxygen measurement drops, this offset will have a diminishing effect.
At a process gas oxygen concentration of 2%, the 1.0mV offset error will only change the reading by 0.1%
oxygen. If in any doubt about the correct offset value, set it to 0.0mV.
The function ’Probe 2 Offset’ will only appear if the transmitter has been configured for 2 oxygen probes.
5.3.2 Lower Line Items
This function allows the operator to change the items that are available to be displayed on the lower line of
the transmitter in Run Mode. If the word “Enabled” appears on the display for a selected lower line option,
the measurement will be available to be shown on the display in the Run Mode by scrolling through the list
using the DISPLAY and DISPLAY buttons.
Each individual lower line measurement can be enabled or disabled by pressing the ENTER button.
OPTIONS:
Probe 1 Dew Point
Probe 1 Pre-Reactive Oxygen %
Probe 2 Dew Point
Probe 2 Pre-Reactive Oxygen %
Average Dew Point
Average Pre-Reactive Oxygen %
Probe 1 TC Temperature
Auxiliary TC Temperature
Probe 2 TC Temperature
Ambient Temperature
Probe 1 EMF
Ambient Relative Humidity %
Probe 2 EMF
Flue Pressure
Probe 1 Impedance
Runtime
Probe 2 Impedance
Service Date
Probe 1 Oxygen %
4-20mA Output 1
Probe 2 Oxygen %
4-20mA Output 2
Average Oxygen %
01
Probe 1 Offset
+0.0 mV
Saved
Setup Menu
03
Lower Line Items
Probe 1 EMF
Enabled
Setup Menu

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1738 Dew Point Transmitter 15
5.3.3 Oxygen Display Units
Options: Oxygen % / Oxygen ppm
Default: Oxygen %
The top line of the display that shows the oxygen measurement can be displayed in either % or parts per
million (ppm)
5.3.4 Damping Factor
Options: No Damping
1 to 10 Samples Averaged
Default: 5 Samples
The oxygen measurement can be damped by averaging successive readings from the probe. This can be
used to smooth out fluctuations in the process gas level and should improve stability of the readings of the
system The larger the number selected here, the more successive readings are averaged and the smoother
the measurement will be.
The damping factor is not applied to the Probe EMF and Probe Temperature values used to calculate
oxygen, but to the oxygen value itself. The pre-damped oxygen value is not displayed or retransmitted via
digital or analog outputs, when damping is enabled the damped oxygen value is shown on the local display
as well as being retransmitted via digital or analog outputs.
5.3.5 Process Alarms
Options: Enabled / Disabled
Default: Disabled
This function allows the operator to “Disable” process alarms. Configuration of the process alarms is not
covered in this manual, please refer to the 1738 Technical Manual for details
04
Oxygen Display Units
Oxygen %
Saved
Setup Menu
05
Damping Factor
5x Samples
Saved
Setup Menu
06
Process Alarms
Disabled
Saved
Setup Menu

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1738 Dew Point Transmitter 17
6. ALARMS
The 1738 Dew Point Transmitter has 4 alarm relays, a built in alarm annunciator and an alarm log. When an
alarm occurs, the Alarm Light will flash. To find out what the alarm is, press the ALARM button.
When the ALARM button has been pressed, the transmitter goes into the Alarm Display Mode. In this mode
some of the buttons take on a different function.
Button text
Run Mode
Alarm Mode
SETUP /RUN
*
Return to Run Mode
DISPLAY /FUNCTION 
*
Next alarm
DISPLAY /FUNCTION 
*
Last alarm
ALARM /OPTION 
Enter Alarm Display Mode
Alarm activated time
ALARM /OPTION 
Enter Alarm Log Mode
Alarm acknowledged time
ALARM ACCEPT /ENTER
*
Acknowledge alarm
GAS 1PURGE 1/SENS IMP
*
*
GAS 2PURGE 2/AUTO CAL
*
*
* This button is not used in the Alarm Display Mode
All relays have fail-safe alarm contacts. That is –
When the transmitter is powered off the contacts are open circuit
When the transmitter is powered on but there are no alarms the contacts will be closed
When there is a current unaccepted alarm event the contacts will be open circuit
When there is a current accepted alarm event the state of the contacts will depend on the selection
in the Commissioning Menu #53. Refer to the 1738 Technical Manual for details.
All alarms drive the alarm light on the front door.
The light will be off if there are no alarms current
The light will flash if there is a current alarm that has not been acknowledged
The light will be on steady if there are current alarm(s) that have not been cleared
The light will flash faster as more alarms occur

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18 1738 Dew Point Transmitter
6.1 Checking and Accepting an Alarm
When a new alarm occurs, either a process alarm or an alarm that will appear in the common alarm list, the
Alarm Light will flash quickly. The more new alarms there are, the faster the light will flash.
To check the cause of the alarm –
1. Press the ALARM button. This will put the transmitter into the current alarm mode. The Setup Light
will flash.
2. The alarm screen will appear displaying the cause of the alarm on the top line.
3. Press the ALARM ACCEPT button to accept the alarm.
4. Press the OPTION button to see the next active alarm or the OPTION button to see the previous
active alarm.
5. When all the new alarms have been ACCEPTED the Alarm Light will stop flashing.
6. Accept each alarm and then press the SETUP /RUN button to return to the Run Mode
6.1.1 Current Alarms
To view the alarms that are still current press the ALARM button from the Run Mode and then use the
ALARM and ALARM buttons to view all alarms. Use the DISPLAY and DISPLAY buttons to view the Time
Activated and the Time Accepted of each alarm.
Probe 2 TC Open/Ct
Time Activated
08 Mar 2006 03:45:29
Status Active
Alarm Description
Time title:
Time Activated
Time Accepted
Time Cleared
Time of the event
Alarm Status:
Active
Accepted
Self Cleared