Teledyne LXT-230 User Manual
Model LXT-230 Transmitter
Installation and Operating Manual
for
pH and ORP
Teledyne Analytical Instruments
16830 Chestnut Street • City of Industry, CA 91748
888-789-8168 • ask_tai@teledyne.com • www.teledyne-ai.com
Model LXT-230 Instruction Manual / 2
TABLE OF CONTENTS
UNPACKING THE INSTRUMENT.................................................................................... 4
1.0 GENERAL DESCRIPTION........................................................................................ 4
1.1 Membrane Switches .......................................................................................... 4
1.2 Digital Display .................................................................................................. 4
1.3 Automatic Buffer Calibration ............................................................................... 4
1.4 Back To Factory Calibration ................................................................................ 4
1.5 Current Output ................................................................................................. 4
1.6 Temperature Conversion .................................................................................... 4
1.7 PID Output (Optional)........................................................................................ 5
1.8 Dual Input (Optional) ........................................................................................ 5
1.9 Dual Output (Optional) ...................................................................................... 5
1.10 Three Outputs (Optional).................................................................................. 5
1.11 Optional Software............................................................................................ 5
1.11.1 Security Access ......................................................................................... 5
1.11.2 Differential Output..................................................................................... 5
1.11.3 Ratio Output ............................................................................................. 5
1.11.4 Averaged Outputs...................................................................................... 5
1.12 Identification .................................................................................................. 5
2.0 INSTALLATION..................................................................................................... 6
2.1 Mounting.......................................................................................................... 6
2.2 Power Wiring .................................................................................................... 6
2.3 Sensor Wiring ................................................................................................... 6
3.0 FAMILIARIZATION................................................................................................ 7
3.1 Key Functions ................................................................................................... 7
3.1.1 Menu Selection Keys.................................................................................... 7
3.1.2 Calibrate Keys............................................................................................. 7
3.2 Display Menus and Screens ................................................................................ 7
3.2.1 Contrast Menu ............................................................................................ 7
3.2.2 Main Menu.................................................................................................. 8
3.2.3 Electrode Diagnostic Screen.......................................................................... 8
3.2.4 Electrode Standardization Menu .................................................................... 8
3.2.5 Electrode Span Menu ................................................................................... 8
3.2.6 Output Calibration Menu............................................................................... 9
3.2.7 Temperature Calibration Menu ...................................................................... 9
4.0 SENTINEL DIAGNOSTICS .................................................................................... 10
4.1 Diagnostic set up and configuration menus......................................................... 10
4.1.1 Main Menu................................................................................................ 10
4.1.2 SENTINEL DIAGNOSTIC SCREEN ................................................................. 10
5.0 MAINTENANCE................................................................................................... 12
5.1 Cleaning ........................................................................................................ 12
5.2 Replacement of the Microprocessor ................................................................... 12
6.0 CALIBRATION .................................................................................................... 13
6.1 Manual Output Mode........................................................................................ 13
6.2 Contrast Adjustment........................................................................................ 13
6.3 One-Point Buffer Calibration (Standardize) ......................................................... 13
6.4 Two-Point Buffer Calibration (Span)................................................................... 14
6.5 Calibration Using a Grab Sample as a Standard................................................... 15
Model LXT-230 Instruction Manual / 3
6.6 Calibration Error Detection & Electrode Operational Guidelines.............................. 15
6.7 Back-to-Factory Calibration .............................................................................. 15
6.8 Output Calibration........................................................................................... 15
6.9 Temperature Calibration - Trim Adjustment........................................................ 16
6.10 Temperature Units Calibration - Celsius/Fahrenheit Conversion ........................... 16
7.0 LXT-230 MODEL NUMBER DESIGNATORS .............................................................. 18
8.0 TROUBLESHOOTING GUIDE................................................................................. 19
APPENDIX A - SPECIFICATIONS................................................................................. 21
Model LXT-230 Instruction Manual / 4
UNPACKING THE INSTRUMENT
Your Teledyne instrument 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 TAI.
3. Save the original packing material until you are satisfied with the contents. In the event
the transmitter must be returned to TAI, the packing material will allow you to properly ship
it to TAI.
4. Familiarize yourself with the instrument before installation, and follow proper installation
and wiring procedures.
1.0 GENERAL DESCRIPTION
Teledyne's Model LXT-230 is a microprocessor-based two-wire transmitter for process
control of pH, ORP and Specific Ion. Incorporating microprocessor technology, the LXT-230
provides the following features:
1.1 Membrane Switches
Calibrations can be performed via membrane switches located on the front cover, removing
the need to open the NEMA 4X enclosure and exposing components to the environment. No
potentiometric adjustments are required.
1.2 Digital Display
A 32-character Supertwist alphanumeric liquid crystal display (LCD) is used to display data
menus. The two rows of 16 characters can be adjusted to different contrast intensities for
easy viewing.
1.3 Automatic Buffer Calibration
Allows buffer points to be defined upon initialization of the transmitter so that no
adjustments are required for future buffer calibrations.
1.4 Back To Factory Calibration
Allows the transmitter to be returned to a predetermined factory calibration. The default
parameters are zero electrode offset at 7.00pH or 0.00mV ORP and the ideal Nernstian
slope for the appropriate measurement.
1.5 Current Output
A standard LXT-230 transmitter is provided with a 4-20 mA current output transmitted on
the same 24-vdc power wiring. The current output may be expanded to any range within
the transmitter's full operating range (see specifications). For customer controllers that are
not capable of reverse acting control, the LXT-230 allows the current output to be reversed;
for example, a 4-20 mA output for a range of 0-14 pH can be reversed to 14-0 pH.
1.6 Temperature Conversion
This standard feature allows the temperature displays to be presented in Celsius or
Model LXT-230 Instruction Manual / 5
Fahrenheit. A toggle function in the Temperature Calibration Menu allows this selection to
be performed in the field.
1.7 PID Output (Optional)
An optional PID output is available and provides a 4-20 mA, three-mode control signal to a
transducer or a final control element. Proportional band is adjustable from 0.1 to 1,000%.
Reset and Rate are adjustable from 0.00 to 100 repeats per minute and 0.00 to 1,000
minutes, respectively.
1.8 Dual Input (Optional)
An optional second input can be provided for pH, ORP, Dissolved Oxygen or Specific Ion.
This input can be used as a second analysis or as specific compensation for the primary
input. Temperature compensation for the secondary input (channel 2) is provided through
the primary input (channel 1).
1.9 Dual Output (Optional)
The standard LXT-230 is provided with a single output; however, the dual output option
provides a second output in either a 4-20 mA regenerated or a 4-20 mA PID format.
Outputs can be defined in pH, ORP, Specific Ion, Dissolved Oxygen or Temperature. The
second output is fully isolated from the inputs and the primary output and is "floating" so it
can have either a positive or negative common.
1.10 Three Outputs (Optional)
Because temperature is an input on the primary channel, TAI has made it available as a
third 4-20 mA output. The third output for the LXT-230 can only be a temperature output.
1.11 Optional Software
To enhance the capability of the LXT-230, other software options are available.
Among the options are:
1.11.1 Security Access
Allows only authorized personnel entry to calibration modes.
1.11.2 Differential Output
Provides an output expressed as the difference between two inputs.
1.11.3 Ratio Output
Provides an output expressed as the ratio of two inputs. This is applicable to percent
rejection in some applications.
1.11.4 Averaged Outputs
1. Provides an output expressed as the average of two inputs.
2. Provides a field selectable time average (2 to 32 seconds).
1.12 Identification
The full model number, as found on the packing slip, is a list of alphanumeric characters
used to designate certain features of the transmitter. See section 10.0 (Table 1) for the list
of designators used for the LXT-230.
Model LXT-230 Instruction Manual / 6
2.0 INSTALLATION
2.1 Mounting
Three typical installation configurations are available for the LXT-230 transmitter: universal
mounting, handrail mounting, and panel mounting configurations. The universal mounting
configuration allows the LXT-230 to be mounted on a wall or a 2” pipe stand. U-bolts may
be ordered separately for pipe stand mounting.
2.2 Power Wiring
The LXT-230 transmitter requires a nominal 24-vdc voltage source. 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.
When connecting the power wires, it is important to observe the polarity. Although no
damage to the LXT-230 will result from polarity reversal, the LXT-230 will not function.
CAUTION
Do NOT apply 110 vac to the 24-vdc wiring terminals. Damage to the instrument
will result!
Multiple channel transmitters can have each channel powered by separate power supplies,
or they can be powered by one power supply.
2.3 Sensor Wiring
A conditioned input is required from the sensor or electrode to the LXT-230 transmitter for
proper operation. In cases where S10 and S17 sensors are not used, a signal conditioning
module is available and can be mounted inside the LXT-230 enclosure.
If preferred, the signal conditioner can be mounted remotely within a separate NEMA 4X
enclosure. When used without an S10 or S17 sensor, signal conditioners for the LXT-230 do
not provide temperature compensation. In these cases, a separate temperature sensing
element is required for input to the temperature compensation circuitry.
Model LXT-230 Instruction Manual / 7
3.0 FAMILIARIZATION
This section will provide an overview of the front panel key functions and the display menus
for a single channel pH and ORP transmitter. Multiple channel transmitters will have the
same menus.
3.1 Key Functions
Cursor positions or numeric adjustments are performed by pressing the appropriate keypad.
The LXT-230 uses an "underline" cursor in each of the menus. Holding down the keypad will
automatically scroll the cursor or numeric values. Please note that simultaneous pressure on
both vertical keys or any combination of keys other than the two horizontal CALIBRATE keys
is not recommended.
3.1.1 Menu Selection Keys
The MENU SELECTION keys are used to change the display menu and move the cursor
vertically. Any menu can be accessed by the use of the appropriate up or down MENU
SELECTION key, advancing the screen to the desired menu. These keys are also used to
exit the calibration mode and save calibration data.
3.1.2 Calibrate Keys
The horizontal CALIBRATE keys are used to enter the calibrate mode and move the cursor
horizontally. To enter the calibrate mode, both horizontal CALIBRATE keys must be pressed
simultaneously. Once in the calibrate mode, the cursor can be positioned by pressing the
individual right-hand or left-hand CALIBRATE keys.
The vertical CALIBRATE keys are used to perform numeric adjustments to displayed values.
To use these keys, the LXT-230 must be in the calibrate mode. Pressing the upper
CALIBRATE key will increase the value; pressing the lower CALIBRATE key will decrease the
value.
To exit the calibrate mode, press either of the MENU SELECTION keys.
3.2 Display Menus and Screens
When the LXT-230 is first powered, the Copyright Display will appear for a few seconds,
then the LXT-230 will display the Main Menu.
The Copyright Display provides the software "version" number and the software serial
number. TAI will require this information if software updates are to be performed. To access
any of the menus listed below, press the desired MENU SELECTION key.
3.2.1 Contrast Menu
Display contrast can be adjusted to allow for variations of ambient lighting. The Contrast
Menu is the same for all LXT-230 transmitters and is the uppermost screen. To access this
menu from the Main Menu, press the upper MENU SELECTION key.
S/N 1234 V 2.01
(C) ECD 2002
Contrast 20
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