Teledyne LXT-280 User Manual
Teledyne Analytical Instruments
OPERATING INSTRUCTIONS FOR
LXT-280
Dissolved Oxygen
Transmitter
DANGER
Toxic gases and or flammable liquids may be present in this monitoring system.
Personal protective equipment may be required when servicing this instrument.
Hazardous voltages exist on certain components internally which may persist
for a time even after the power is turned off and disconnected.
Only authorized personnel should conduct maintenance and/or servicing.
Before conducting any maintenance or servicing, consult with authorized
supervisor/manager.
P/N M
ECO:
LXT-280
Teledyne Analytical Instruments ii
Copyright © 2006 Teledyne Instruments/ Analytical Instruments
All Rights Reserved. No part of this manual may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any other language or computer language in
whole or in part, in any form or by any means, whether it be electronic, mechanical,
magnetic, optical, manual, or otherwise, without the prior written consent of Teledyne
Instruments/ Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91749-
1580.
Warranty
This equipment is sold subject to the mutual agreement that it is warranted by us free from
defects of material and of construction, and that our liability shall be limited to replacing or
repairing at our factory (without charge, except for transportation), or at customer plant at
our option, any material or construction in which defects become apparent within one year
from the date of shipment, except in cases where quotations or acknowledgements provide
for a shorter period. Components manufactured by others bear the warranty of their
manufacturer. This warranty does not cover defects caused by wear, accident, misuse,
neglect or repairs other than those performed by TI/AI or an authorized service center. We
assume no liability for direct or indirect damages of any kind and the purchaser by the
acceptance of the equipment will assume all liability for any damage which may result from
its use or misuse.
We reserve the right to employ any suitable material in the manufacture of our apparatus,
and to make any alterations in the dimensions, shape or weight of any parts, in so far as
such alterations do not adversely affect our warranty.
Important Notice
This instrument provides measurement readings to its user, and serves as a tool by which
valuable data can be gathered. The information provided by the instrument may assist the user
in eliminating potential hazards caused by his process; however, it is essential that all
personnel involved in the use of the instrument or its interface, with the process being
measured, be properly trained in the process itself, as well as all instrumentation related to it.
The safety of personnel is ultimately the responsibility of those who control process
conditions. While this instrument may be able to provide early warning of imminent
danger, it has no control over process conditions, and it can be misused. In particular, any
alarm or control systems installed must be tested and understood, both as to how they
operate and as to how they can be defeated. Any safeguards required such as locks, labels,
or redundancy, must be provided by the user or specifically requested of TI/AI at the time
the order is placed.
Therefore, the purchaser must be aware of the hazardous process conditions. The purchaser
is responsible for the training of personnel, for providing hazard warning methods and
instrumentation per the appropriate standards, and for ensuring that hazard warning devices
and instrumentation are maintained and operated properly.
Teledyne Instruments/ Analytical Instruments, the manufacturer of this instrument, cannot
accept responsibility for conditions beyond its knowledge and control. No statement
expressed or implied by this document or any information disseminated by the
manufacturer or its agents, is to be construed as a warranty of adequate safety control under
the user’s process conditions.
Dissolved Oxygen Transmitter
Teledyne Analytical Instruments iii
Specific Model Information
Instrument Serial Number: _______________________
Instrument Range: _______________
Calibrated for: _______________
LXT-280
Teledyne Analytical Instruments iv
Safety Messages
Your safety and the safety of others is very important. We have
provided many important safety messages in this manual. Please read
these messages carefully.
A safety message alerts you to potential hazards that could hurt you
or others. Each safety message is associated with a safety alert symbol.
These symbols are found in the manual and inside the instrument. The
definition of these symbols is described below:
GENERAL WARNING/CAUTION: Refer to the
instructions for details on the specific danger. These cautions
warn of specific procedures which if not followed could cause
bodily Injury and/or damage the instrument.
CAUTION: HOT SURFACE WARNING: This warning is
specific to heated components within the instrument. Failure
to heed the warning could result in serious burns to skin and
underlying tissue.
WARNING: ELECTRICAL SHOCK HAZARD: Dangerous
voltages appear within this instrument. This warning is
specific to an electrical hazard existing at or nearby the
component or procedure under discussion. Failure to heed this
warning could result in injury and/or death from
electrocution.
Technician Symbol: All operations marked with this symbol
are to be performed by qualified maintenance personnel only.
NOTE: Additional information and comments regarding a
specific component or procedure are highlighted in the form
of a note.
CAUTION: THE ANALYZER SHOULD ONLY BE USED FOR THE
PURPOSE AND IN THE MANNER DESCRIBED IN
THIS MANUAL.
No
Symbol
Dissolved Oxygen Transmitter
Teledyne Analytical Instruments v
IF YOU USE THE ANALYZER IN A MANNER OTHER
THAN THAT FOR WHICH IT WAS INTENDED,
UNPREDICTABLE BEHAVIOR COULD RESULT
POSSIBLY ACCOMPANIED WITH HAZARDOUS
CONSEQUENCES.
This manual provides information designed to guide you through
the installation, calibration operation and maintenance of your new
process controller. Please read this manual and keep it available.
Occasionally, some instruments are customized for a particular
application or features and/or options added per customer requests.
Please check the front of this manual for any additional information in
the form of an Addendum which discusses specific information,
procedures, cautions and warnings that may be peculiar to your
instrument.
Manuals do get lost. Additional manuals can be obtained from
TI/AI at the address given in the Appendix. Some of our manuals are
available in electronic form via the internet. Please visit our website at:
www.teledyne-ai.com.
LXT-280
Teledyne Analytical Instruments vi
Table of Contents
List of Figures............................................................................ viii
List of Tables ............................................................................... ix
Introduction .................................................................................. 1
1.1 Overview 1
1.2 Main Features of the Transmitter 2
1.3 Optional Features 2
1.4 Front Panel 2
1.5 Model Identification 4
Installation .................................................................................... 5
2.1 Unpacking the Instrument 5
2.2 Mounting 5
2.3 Wiring 7
2.3.1 Site Wiring 7
2.3.2 Power Wiring 7
2.3.3 Sensor Wiring 8
2.3.4 DC Power 8
2.4 Configuring the LXT-280 9
2.5 Calibration 9
Operation .................................................................................... 11
3.1 Using the Front Panel Keys 11
3.2 Menus 12
3.2.1 Contrast 13
3.2.2 Main Menu 14
3.2.3 Electrode Data Screen 14
3.2.4 Electrode Zero Menu 15
3.2.5 Electrode Span Menu 16
Dissolved Oxygen Transmitter
Teledyne Analytical Instruments vii
3.2.6 Output Calibration Menu 16
3.2.7 DO Locus 16
3.2.8 Temperature Calibration Menu 17
Calibration ...................................................................................19
4.1 Calibration 19
4.2 Manual Output Mode 19
4.3 Contrast Adjustment 20
4.4 Zero Calibration 21
4.5 Span Calibration 22
4.6 Automatic Buffer Calibration 24
4.7 Calibration Error Detection 24
4.8 Back-to-Factory Calibration 25
4.9 Output Calibration 26
4.10 Locus Calibration 27
4.11 Temperature Calibration 27
4.11.1 Temperature Adjustment 27
4.11.2 Temperature Calibration—Manual TC Adjustment 28
4.11.3 Temperature Units Calibration – °C/°F Conversion 29
Calibration Correction Factors...................................................31
5.1 Calibration Correction Factors 31
5.2 Salinity Correction 34
5.3 Calibration Example 35
5.4 Grab Sample Calibration 35
5.5 Dissolved Oxygen Units of Measurement 36
Maintenance ................................................................................37
6.1 Routine Maintenance 37
6.1.1 Cleaning 37
6.1.2 Replacement of the Microprocessor: 37
Appendix .....................................................................................41
A.1 Specifications 41
A.2 Spare Parts Listing 43
Index ............................................................................................45
LXT-280
Teledyne Analytical Instruments viii
List of Figures
Figure 1-1: LXT-280 User Interface ................................................ 3
Figure 2-1: Typical Installation for the LXT-280 Transmitter............ 6
Figure 2-2: Intrinsically Safe Wiring Diagram .................................. 7
Figure 2-3: LXT-280 Wiring ............................................................ 8
Figure 3-1: LXT-280 Operator Interface........................................ 11
Figure 3-2: Available Menus ......................................................... 13
Dissolved Oxygen Transmitter
Teledyne Analytical Instruments ix
List of Tables
Table 5-1: Oxygen Saturation vs. Temperature.............................32
Table 5-2: Relative Humidity Correction Factors ...........................33
Table 5-3: Elevation Correction Factor..........................................33
Table 5-4: Salinity Correction Factor .............................................34
Table 6-1: Troubleshooting ...........................................................38
LXT-280
Teledyne Analytical Instruments x
DANGER
COMBUSTIBLE GAS USAGE
WARNING
This is instrument is Factory Mutual Approved as an
intrinsically safe and explosion proof gas analyzer for use in
Class I, II, and III Divisions 1 Groups A through G hazardous
areas. This approval applies only to the equipment specified
and installed in accordance with the information contained
within this manual. It is the customer's responsibility to
ensure safety especially when combustible gases are being
analyzed since the potential of gas leaks always exist.
The customer should ensure that the principles of operating
of this equipment is well understood by the user and that the
instrument as well as any approved support equipment is
properly installed. Misuse of this product in any manner,
tampering with its components, or unauthorized substitution
of any component may adversely affect the certification and
the safety of this instrument.
Since the use of this instrument is beyond the control of
Teledyne, no responsibility by Teledyne, its affiliates, and
agents for damage or injury from misuse or neglect of this
equipment is implied or assumed.
Dissolved Oxygen Transmitter Introduction
Teledyne Analytical Instruments 1
Introduction
1.1 Overview
Teledyne’s Model LXT-280 Transmitter is a robust and versatile
instrument for measurement and process control of dissolved oxygen.
This instrument is Factory Mutual Approved as intrinsically safe and
explosion proof for use in Class I, II, and III Divisions 1 Groups A
through G hazardous areas. The Model LXT-280 transmitters provide
solutions to a variety of liquid analytic applications involving hazardous
areas. The LXT-280 accepts input from a variety of sensors for specific
process measurements such as:
• Dissolved Oxygen (DO)
• pH
• Resistivity ( or conductivity)
• Oxidation-Reduction Potential (ORP)
• Specific Ion
The standard instrument is powered from an external 24 VDC
source and is equipped with a 4-20mA current output transmitted on the
same 24 VDC wiring. The power supply and electronics are remote from
each other and for FM approval, should be connected through an
intrinsic safety barrier. Separate compartments in the stainless steel
explosion proof housing keep the wiring and the electronics separate and
sealed from each other. This prevents the sensitive electronics from
being exposed to hostile environments.
The LXT-280 is housed in a Factory Mutual Approved explosion
proof stainless steel NEMA-7C housing. The operator interacts with the
instrument via magnetic switches located on the front panel behind a
removable cover. The magnetic switches can be activated without
having to open the cover.
This transmitter is capable of measuring dissolved oxygen in ppm
or in the percent oxygen range.
Introduction LXT-280
Teledyne Analytical Instruments 2
1.2 Main Features of the Transmitter
The LXT-280 Transmitter for dissolved oxygen applications
incorporates the following standard features:
• Magnetic switches located behind a glass window can be
activated without having to open the instrument.
• Menu driven backlit display with contrast adjustment
• Automatic Calibration. This allows calibration points to be
defined upon initialization of the transmitter.
• An easy back to factory calibration menu allows the instrument
to return to a predetermined factory calibration. The default
parameters are: zero electrode offset at 0 ppm or 0% oxygen and
-400 mV at full scale.
• 4-20mA current output transmitted on the same 24 VDC power
wiring. The current output is fully expandable to any range
within the transmitter’s full operating range. The current output
can be configured to be reverse acting.
• Temperature Conversion. Temperature can be displayed in either
Fahrenheit or Celsius. The units can be toggled from one to the
other in the field with the conversion calculation performed
automatically.
1.3 Optional Features
The Model LXT-280 Transmitter is a versatile instrument designed
to meet the needs for liquid analytics and process control across a wide
range of applications. Options available for this transmitter includes:
Optional Software
Security Access—keyboard security option: Allows only
authorized personnel entry to calibration modes.
1.4 Front Panel
The operator interfaces with the instrument through a sight glass
window using magnetically activated arrow keys. This is accomplished
by touching an instrument magnet to the glass window directly over the
Dissolved Oxygen Transmitter Introduction
Teledyne Analytical Instruments 3
appropriate magnetic switch. The LXT-280 uses an "underline" cursor in
each of the menus.
Figure 1-1 shows the user interface for the LXT-280 instrument.
The interface includes the LCD display capable of outputting
alphanumeric information in 2 rows of 16 characters per row and 4
magnetic switch arrow keys that control the operation of the unit.
Figure 1-1: LXT-280 User Interface
The keys are in two groups:
VERTICAL UP/DOWN (▲/▼) Arrow Keys
• These keys are used to change the display menu.
• They also move the cursor vertically. Any menu can be
accessed by magnetically activating the appropriate UP or
DOWN key
• These keys also perform numeric adjustments to display
values while in the calibrate mode. Magnetically activating
the up vertical arrow key will increase the value or
magnetically activating the down vertical arrow key will
decrease the value.
Introduction LXT-280
Teledyne Analytical Instruments 4
HORIZONTAL LEFT/RIGHT (◄/►) Arrow Keys
• The right and left arrows are used to enter the calibrate mode.
To enter the calibrate mode, magnetically activate the right
horizontal arrow key. Once in the calibrate mode, the cursor
can be positioned by magnetically activating the right or the
left horizontal arrow key. To exit the calibrate mode,
magnetically activate left horizontal arrow key until the
cursor is all the way to the left.
• These keys also move the cursor horizontally.
1.5 Model Identification
The LXT-280 Transmitter is a 24VDC unit. The instrument is
configured at the factory for the customer’s application and so there are
many different model designators.
The following codes will help in identifying a specific instrument
configuration.
Base Model:
LXT-280 LXT-280 Transmitter
Channel 1 Input with 4-20mA Output:
-DO/MA Dissolved Oxygen (specify ppm or %)
-PH/MA pH
-ORP/MA Oxidation Reduction Potential (REDOX)
-PION/MA Specific ion
-CD/MA Conductivity, 0-20 mS
-CDT/MA Conductivity Toroidal (form 50mA to 1S)
-RS/MA Resistivity (0 to 50 megohms)
Mounting Hardware:
-UM Universal mounting plate
Other Options:
KSx Keyboard Security Code (x = level of security,
see Security Code Option)
Dissolved Oxygen Transmitter Installation
Teledyne Analytical Instruments 5
Installation
Installation of the LXT-280 Transmitter involves:
• Unpacking the instrument
• Mounting
• Making Electrical Connections
• Configuring the Instrument
• Calibration
2.1 Unpacking the Instrument
The LXT-280 Transmitter has been carefully packaged to protect it
from damage during shipment and dry storage. Upon receipt please
follow the procedure outlined below:
1. Before unpacking, inspect the condition of the shipping container
to verify proper handling by the carrier. If damage is noted, save
the shipping container as proof of mishandling for the carrier.
2. Check the contents of the shipping container with the items and
quantities shown on the packing list. Immediately report any
discrepancies to TI/TAI.
3. Save the original packing material until you are satisfied with the
contents. In the event the transmitter must be returned to the
factory, the packing material will allow you to properly ship it to
TI/TAI.
4. Familiarize yourself with the instrument before installation, and
follow proper installation and wiring procedures.
2.2 Mounting
The LXT-280 transmitter can be wall mounted or pipe mounted.
Installation drawings with dimensions are included at the back of this
manual. The power supply must be located in a non-hazardous area
while the transmitter and sensor can be installed in a hazardous
Installation LXT-280
Teledyne Analytical Instruments 6
environment as shown in Figure 2-1. For intrinsically safe installation,
an FM approved safety barrier must be installed between the power
supply/receiver and the transmitter as shown in Figure 2-2.
CAUTION: USE ONLY FM APPROVED SAFETY BARRIERS.
CONTACT TELEDYNE FOR A LIST OF FM
APPROVED INTRINSIC SAFETY BARRIERS FOR
YOUR APPLICATION.
If mounting hardware is ordered with the instrument, it has been
factory assembled and the LXT-280 is ready for mounting. A sunshade
should be considered during the selection of the mounting location
this prevents direct sunlight from creating an oven effect inside of the
enclosure.
Figure 2-1: Typical Installation for the LXT-280 Transmitter
Dissolved Oxygen Transmitter Installation
Teledyne Analytical Instruments 7
Figure 2-2: Intrinsically Safe Wiring Diagram
2.3 Wiring
2.3.1 Site Wiring
Two conduits should be run to the transmitter locat i o n , one for
the sensor and the other for the 24 VDC-power source. Proper methods
of terminating the conduit for hazardous locations should be reviewed
by your local plant safety engineer based on State and Federal
requirements.
2.3.2 Power Wiring
For power wiring, the LXT-280 transmitter requires a nominal 24VDC voltage source. With zero loop impedance, the minimum voltage
requirement is 14 VDC. The maximum voltage limit is 50 VDC.
Maximum loop impedance at 24 VDC is 450 ohms for the 4-20 mA
compliance. Impedance levels higher than 450 ohms will require
additional DC voltage.
Figure 2-3 illustrates the proper 24 VDC power wiring for the LXT280 transmitter. When connecting the power wires, it is important to
Installation LXT-280
Teledyne Analytical Instruments 8
observe the polarity. Although no damage to the LXT-280 will result
from polarity reversal, the instrument will not function.
For intrinsically safe wiring see Figure 2-2.
CAUTION: DO NOT APPLY 110 VAC TO THE 24 VDC WIRING
TERMINALS. DAMAGE TO THE INSTRUMENT WILL
RESULT!
2.3.3 Sensor Wiring
A conditioned input is required from the sensor or electrode to the
LXT-280 transmitter for proper operation. Teledyne models SP-1 and SP2 sensors will provide the required conditioning. Figure 2-3 illustrates the
proper wiring of the sensor to the LXT-280 transmitter.
Figure 2-3: LXT-280 Wiring
2.3.4 DC Power
The LXT-280 requires an external 24 VDC power source to
operate. With zero loop impedance, the minimum voltage requirement is
13.5 VDC. The maximum voltage limit is 50 VDC. Maximum loop
impedance at 24 VDC is 525 ohms for the 4-20 mA compliance.
Impedance levels higher than 525 ohms will require additional DC
voltage.
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