Teledyne Oxygen Equipment LXT 220 User Manual

OPERATING INSTRUCTIONS FOR

LXT-220

Dissolved Oxygen

Controller

P/N Mxxxxx

ECO:

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.

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Dissolved Oxygen Controller

Specific Model Information

Instrument Serial Number: _______________________

Instrument Range:

Calibrated for:

_______________

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LXT-220 DO

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.

Symbol

CAUTION:

THE ANALYZER SHOULD ONLY BE USED FOR THE

PURPOSE AND IN THE MANNER DESCRIBED IN

THIS MANUAL.

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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.

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Table of Contents

List of Figures..............................................................................ix

List of Tables ................................................................................x

Introduction ................................................................................ 13

1.1 Overview

1.2 Main Features of the Transmitter

1.3 Optional Features

1.4 Front Panel

1.5 Internal Connections

Installation .................................................................................. 19

2.1 Unpacking the Instrument

2.2 Mounting

2.3 Electrical Connections

2.3.1 AC Power

2.3.2 Sensor Wiring

2.4 Configuring the LXT-220

2.5 Calibration

Operation .................................................................................... 23

3.1 Using the Front Panel Keys

3.1.1 Menu Selection Keys

3.1.2 Calibrate Keys

3.2 Menus

3.2.1 Contrast

3.2.2 Main Menu

3.2.3 Output Graph

3.2.4 Parameter Selection Menu

3.2.4.1 Calibration Submenu

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3.2.4.2 Setup Submenu

3.2.4.3 Status Menu

3.2.4.4 Exit/Stay Menu

3.3 Configuring the LXT-220

3.3.1 Password Protection

3.3.1.1 Changing Protection Level

3.3.1.2 Changing Operational Password

3.3.1.3 Changing Configuration Password

3.3.2 4-20 mA Output Assignments

3.3.3 Manual Mode Assignment

3.3.4 HART Output Assignments

3.3.5 Relay Assignments

3.3.6 Temperature Calibration

3.3.7 4-20 Trim

3.3.8 Input A/D Converter Trim

3.3.9 PID Assignments

3.4 Calibration

3.4.1 Manual Output Mode

3.4.2 Parameter Selection Menu

3.4.2.1 Buffer Menu

3.4.2.2 One-Point Buffer Calibration (Standardize)

3.4.2.3 Two-Point Buffer Calibration (Span)

3.4.2.4 Calibration Using a Grab Sample as a Standard 48

3.4.2.5 Calibration Error Detection & Electrode

Operational Guidelines

3.4.2.6 Back-to-Factory Calibration

Maintenance ................................................................................51

4.1 Routine Maintenance

4.1.1 Cleaning

4.1.2 Replacement of the Microprocessor:

Appendix .....................................................................................53

A.1 Specifications

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A.4 Model Designation

Index............................................................................................ 59

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Dissolved Oxygen Controller

List of Figures

Figure 1-1: LXT-220 Front Panel...................................................16

Figure 1-2: Internal Layout of the LXT-220 DO Controller .............17

Figure 2-1: Opening the Front Panel.............................................20

Figure 2-2: LXT-220 Electrical Connections..................................21

Figure 3-1: Available Menus and Submenus.................................25

Figure 3-2: Numerical Entry Using Front Panel Keys ....................32

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List of Tables

Table 3-1: Protection Level Exceptions......................................... 33

Table 4-1: Troubleshooting........................................................... 52

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Dissolved Oxygen Controller

This is a general purpose instrument designed for liquid

measurements in a non-hazardous area. It is the customer's

responsibility to ensure safety especially when hot or

flammable liquids are being analyzed since the potential of

leaks always exist.

The customer should ensure that the principles of operating

this equipment are well understood by the user. Misuse of

this product in any manner, tampering with its components,

or unauthorized substitution of any component may

adversely affect the safety of this instrument.

Since the use of this instrument is beyond the control of

Teledyne Instruments/ Analytical Instruments, referred as

TI/AI, no responsibility by TI/AI, its affiliates, and agents for

damage or injury from misuse or neglect of this equipment is

implied or assumed.

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Dissolved Oxygen Controller

Introduction

1.1 Overview

Teledyne’s Model LXT-220 Dissolved Oxygen Controller is a

robust and versatile instrument for the measurement and process control

of dissolved oxygen in a liquid component. Highly customizable, the

Model LXT-220 comes standard with a single 4-20mA current output

but can have as many as five. The current output is field selectable and

may be expanded to any range within the transmitter’s full operating

range. It can also be programmed as reverse acting; for example, a 4-20

mA output for a range of 0 to 10 ppm can be reversed to 10 to 0 ppm.

The standard instrument accepts a single input typically from a

Teledyne SP1 or SP2 Dissolved Oxygen probe however a dual input

option is available. This optional dual input extends the functionality of

the instrument to accept conditioned input from a variety of sensors for

specific process measurements such as:

• Second Dissolved Oxygen (DO) channel

• Resistivity/conductivity

• pH

• Oxidation-Reduction Potential (ORP)

• Specific Ion

For process control, the microprocessor based LXT-220

Transmitter employs a multi-bus system architecture for PID

temperature control and sensor-specific process variable outputs such as

DO, pH, ORP, Resistivity/Conductivity, and ion-specific element (ISE)

output as a function of multiple inputs. Up to six field-configurable

alarm or control relay outputs are available to the user to match

individual process needs. These relays can be field configured as high or

low alarms. Hysterisis (dead band) is defined by setting the ON and OFF

relay values. These relays can be configured to any of the input

parameters. (See Section 3.3.5).

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Introduction

LXT-220 DO

The LXT-220 can be upgraded with pre-pHault Diagnostics &

HART Communications option which alerts the operator to a pending

DO, pH, ORP, or ISE electrode failure.

The LXT-220 is housed in a rugged NEMA-4X housing with all

operator switches conveniently located on the front panel.

1.2 Main Features of the Transmitter

The LXT-220 Controller for dissolved oxygen applications

incorporates the following standard features:

• Front panel membrane switches

• 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 and –157.5mV/FS slope.

• 4-20mA current output fully expandable to any range within the

transmitter’s full operating range. The output is field selectable

and fully programmable. 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-220 DO Controller is a versatile instrument

designed to meet the needs for liquid analytics and process control

across a wide range of applications. There are many options available

for the transmitter including:

• Dual Input: An optional second input can be provided for pH,

ORP, resistivity/conductivity, or Specific Ion. The second input

can also be used as a second analysis for dissolved oxygen or as

specific compensation for the primary input.

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Introduction

• PID Output: An optional PID output is available and provides a

4-20 mA, three-mode control signal. 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. The PID output can be assigned and configured to

any of the available outputs.

• Multiple Output: The standard LXT-220 DO Controller is

provided with a single output. With the multiple output option,

up to four additional outputs can be added. These outputs can be

defined in the field as the process variable (DO, pH, ORP,

resistivity, conductivity), temperature, or PID. The additional

outputs are fully isolated from the inputs and the primary output

and are "floating" so they can have either a positive or negative

common.

Note: These isolated outputs are floating and require an external

24 VDC power source to operate. TI/AI can supply an

internal 24 VDC power supply to power these outputs.

Contact the factory for additional information.

• Alarm Relays: Up to six alarm or control relays are available for

the primary channel, or divided between the two channels on

dual output transmitters. Relay outputs can be field configured as

high or low alarms. Hysteresis (dead band) is defined by setting

the "ON" and "OFF" relay values. The relays can be configured

to any of the input parameters.

• HART Output: This option provides both digital and analog

outputs that is useful for monitoring and controlling process

variables in a multiple output instrument.

• Optional Software

Differential Output: Provides an output expressed as the

difference between two inputs.

Ratio Output: Provides an output expressed as the ratio of two

inputs. This is applicable to percent rejection in some

applications.

Averaged Output: Provides an output expressed as the average

of two inputs.

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Introduction

LXT-220 DO

1.4 Front Panel

The operator interfaces with the instrument from the front panel.

Figure 1-1 shows a standard single channel LXT-220 DO instrument

front panel. The panel includes the LCD display capable of outputting

information in both a textural and graphical format. There are 6

membrane switches (keys) that control the operation of the unit. The

keys are in two groups:

MENU SELECT: UP/DOWN (▲/▼) These keys are used to

change the display menu and move the cursor vertically. Any

menu can be accessed using the appropriate MENU SELECT key.

These keys are also used to exit the calibration mode and save

calibration data.

CALIBRATE KEYS: UP/DOWN/LEFT/RIGHT (▲/▼/◄/►)

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 appropriate individual CALIBRATE

key. These keys are also used to select an item from a menu. See

Section 3.1)

The vertical CALIBRATE keys are used to perform numeric

adjustments to displayed values. Pressing the ▲ CALIBRATE key

will increase the value; pressing the ▼ CALIBRATE key will

decrease the value.

Figure 1-1: LXT-220 Front Panel

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Introduction

1.5 Internal Connections

All user connections are made inside the unit on removable terminal

blocks. Two conduit holes are provided on the NEMA-4X housing, one for

low level DC signal and the other for 115VAC power wiring. Access to the

terminal blocks is gained after removing the 4 captive jackscrews on the

front of the instrument. Figure 2 shows the internal layout of the LXT-220

Controller. A label on the enclosure cover shows the terminal block

arrangement for all the wiring along with the model number and the factory

assignment of the output signals. These can be changed in the field if the

application prefers a different arrangement.

Figure 1-2: Internal Layout of the LXT-220 DO Controller

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Introduction

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Dissolved Oxygen Controller

Installation

Installation of the LXT-220 Controller involves:

• Unpacking the instrument

• Mounting

• Making Electrical Connections

• Configuring the Instrument

• Calibration

2.1 Unpacking the Instrument

The LXT-220 Controller 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

Three typical installation configurations are available for the LXT-

220:

• Universal mounting plate

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• Handrail mounting plate

• Panel mounting configurations.

U-bolts may be ordered separately. Refer to the following

application drawings for mounting details:

4024011 Dimensions, wall & pipe mounting.

The unit is supplied with a universal-mounting bracket. Two slots

on each side will accommodate U-Bolts for pipe mounting.

4024012 Dimensions, Panel Mounting. This installation uses 1/4"

screws. Panel mounting is accommodated using the captive

jackscrew that will cinch the instrument bezel against the panel.

2000268 Dimensions, handrail mounting.

These application drawings can be located in the back of this

manual.

2.3 Electrical Connections

All electrical connections are made with connectors to a panel

inside the NEMA-4X enclosure. To gain access to the panel, use a flat-

blade screwdriver to remove the 4 captive screws on the front of the

instrument and swing the panel out. See Figure 2-1.

Figure 2-1: Opening the Front Panel

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Installation

2.3.1 AC Power

The LXT-220 requires a 115 VAC 60 Hz power source. A 24VDC

unit is available as an option.

CAUTION:

MAKE SURE THE CIRCUIT BREAKER PROTECTING

THE AC INPUT LINE IS OFF BEFORE WIRING THE

LXT-220.

Application drawing 4024003 illustrates the proper power wiring

for single channel LXT-220 as does the affixed label on the backside of

the front panel. The wires are best fed through the right conduit as

shown in Figure 2-2.

Figure 2-2: LXT-220 Electrical Connections

2.3.2 Sensor Wiring

A conditioned input is required from the sensor or electrode to the

LXT-220 for proper operation. Teledyne’s SP1 and SP2 sensors will

provide the required conditioning. The application drawing 4024003

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Installation

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illustrates the proper sensor wiring and is also shown on the affixed label

on the backside of the front panel.

2.4 Configuring the LXT-220

The LXT-220 Controller is used for measurement and control for a

wide range of liquid analytical applications. This manual describes the

configuration for use in dissolved oxygen measurement and control

applications. If your instrument included optional features such as dual

channel input for handling other specific measurement processes, a

second manual will be included to describe the setup and operational

parameters specific to that function.

Configuring the instrument is described in Section 3 of this manual.

2.5 Calibration

Prior to using the instrument for the first time, the LXT-220 must

be calibrated. The specific calibration procedure used depends on the

application. Among other things, the calibration routine establishes the

correspondence between the 4-20mA output signal and the application

dependant measurable parameter. This manual describes operation for

dissolved oxygen measurements and process control for the LXT-220.

Calibration can be performed without disturbing control or recorder

functions using a manual output mode (see Section 3.4.1). Typically, the

calibration is done using either a one point buffer calibration

(standardization) or two point (span) calibration. There is also a Back to

Factory calibration feature which resets the LXT-220 to “typical

electrode” for electrode potentials. As the electrode ages it will

deteriorate and the mV/FS will decay and eventually require

replacement. If the membrane is torn or coated the calibration will be

either sluggish or out of range. This feature restores the instrument to

the predetermined factory calibration point of zero electrode offset

and –157.5 mV/FS quickly.

The calibration routines require a familiarity with the instrument

operation and is described after fundamental operational parameters are

discussed in Section 3.

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Dissolved Oxygen Controller

Operation

No one instrument has all the options described in this document.

Some options must be specified at the time the instrument is purchased,

and are not field-alterable. The instrument can be returned to the factory

for re-programming if your requirements change.

3.1 Using the Front Panel Keys

Cursor positions or numeric adjustments are performed by pressing

the appropriate keypad. The LXT-220 uses an "underscore" cursor in

each of the menus. Holding down the keypad will automatically scroll

the cursor or numeric values.

Note: Simultaneous pressing 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:

1. 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.

2. Exit the calibration mode and save calibration data.

3.1.2 Calibrate Keys

1. 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.

2. Once in the calibrate mode, the cursor can be positioned by

pressing the individual right-hand or left-hand horizontal

CALIBRATE keys.

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3. With the cursor on a user selectable menu item, for instance

SETUP in the Parameter Selection Menu, pressing both

horizontal CALIBRATE keys will take you to the next lower

level of screens: 4-20 mA screen, Relay Setup screen, etc.

4. The vertical CALIBRATE keys are used to perform numeric

adjustments to displayed values. To use these keys, the LXT-

220 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 Menus

The LXT-220 contains a series of menus and submenus from which

different functions can be accessed. Even though the display only shows

4 menus per screen, you can scroll through all available menus by using

the MENU SELECT ▲ and ▼ keys.

The menus available in the standard LXT-220 instrument

configured for single channel dissolved oxygen controllers are shown in

Figure 3-1.

When the instrument is first powered up, a copyright display will

appear for a few seconds. This screen displays the serial number and

software version for your instrument. After a few seconds the display

changes to the main menu. From the main menu, you can scroll up (▲)

to the contrast menu or down (▼) through the available menus for your

controller.

S/N 1004

(C)TI/TAI

V 1.00

2002

Some menus allow you to choose from several options. To select

an option or item, scroll to the option using the MENU SELECT ▲/▼

keys. When the cursor is next to the item of interest select the item by

simultaneously pressing both the left and right (◄/►) CALIBRATE

arrow keys on the right side of the front panel.

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Operation

There may be additional menus not shown in Figure 3-1 depending

on the options you selected.

Figure 3-1: Available Menus and Submenus

In this manual, screens with a gray background are related to

dissolved oxygen measurement or control while white background

screens relate to a second channel process, for instance, ORP related

screens. When there is only one gray screen the information applies to

both process applications, for example, the contrast screen discussed

next adjusts the contrast for all screens.

3.2.1 Contrast

Display contrast can be adjusted to allow for variations of ambient

lighting and viewing angle by using this menu. The Contrast Menu is

the same for all LXT-220 controllers and is always located as the

uppermost menu. To access this menu from the Main Menu, press the

▲ MENU SELECT key.

Contrast

Contrast Menu

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Procedure:

1. Press the upper MENU SELECTION key to reach the Contrast

Menu.

2. Press both horizontal CALIBRATE keys simultaneously to enter

the calibrate mode. Observe the cursor move to the last digit.

3. Using the horizontal CALIBRATE keys, position the cursor

under the digit to be adjusted.

4. Increase or decrease the value by pressing the appropriate

vertical CALIBRATE key.

5. To save the contrast value and exit the calibrate mode, press

either MENU SELECTION key.

3.2.2 Main Menu

This menu appears after the copyright display when power is first

applied to the LXT-220. The MAIN MENU displays the measured

process variable, temperature, and the current output in percent of full-

scale. While in this menu, the current output can be adjusted and locked

in a manual mode to provide an undisturbed output during sensor

calibrations. The screens below are for a two-channel instrument. To

access the following menus in a two-channel instrument scroll down for

channel 1 and scroll up for channel 2. For a single channel instrument

scrolling down accesses all menus.

2 DO 8.40

84.0%

1 DO 9.28

92.8%

2 ORP 500

50.0%

25.0^OC

Main Menu, pH

Main Menu, ORP

3.2.3 Output Graph

This screen graphically displays the output current that is set up in

the Main screen. The X-axis of the graph display is factory set to ~150

samples (~15min @ 6 sec or .1min/sample). The setup screen sets the

Y-axis (the sensitivity). If the graph were assigned to a current output

the sensitivity would be that of the 4 to 20 mA output.

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Operation

Graph

3.2.4 Parameter Selection Menu

Buffer

Setup

Status

Parameter Selection Menu

This menu allows you to select what function you would like to

perform.

With the cursor on BUFFER, if you press ◄ and ► together the

LXT-220 will enter the calibration menus (standardize and span).

Scrolling to and choosing SETUP brings you to where you can

configure and setup the instrument. The STATUS section allows the

user to view the calibration engineering data (mV input from the sensor

and the zero potential from the last cal). Each section is entered by

placing the cursor under the first letter of the section you wish to enter

and pressing the two horizontal calibrate keys simultaneously. The

Parameter Selection Menu is discussed in detail in Section 3.4.2.

3.2.4.1 CALIBRATION SUBMENU

Choosing BUFFER from the Parameter Selection Menu brings up a

submenu that allows the user to perform a 1 or 2 point buffer calibration

(standardize & span). This menu is described in detail in Section 3.4.2

Calibration.

1 DO

Cal

.00 ppm

.0 mV

Zero Calibration Menu DO

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3.2.4.2 SETUP SUBMENU

Choosing SETUP from the Parameter Selection Menu brings up the

first of a series of screens that allows the user to configure some initial

parameters in the LXT-220 controller. These parameters are:

• 4 to 20 mA outputs

• relay contacts

• PID control

• HART

You can also setup how the graphic display plots the current output

using the Plot function. The menu below shows the Plot function. In this

case, the process variable assigned to Channel 1 is plotted and sampled

every 6 seconds (.1 min).

Plot

Sample

4-20 1

.1 m

(ch1 PV)

Current output menu

To set up additional parameters or to change to current preset

parameters refer to Section 3.3 Configuring the LXT-220 in this manual.

3.2.4.2.1 CURRENT OUTPUT SETUP

This menu is used to set or adjust the current output range with the

process variable. The top line defines the 4 mA point, while the bottom line

defines the 20 mA point. Between these points, the output current is linear

with respect to the sensor input. The standard LXT-220 provides a single

output channel but options are available to expand the number of current

outputs to 4. See Section 3.3 Configuring the LXT-220 in this manual for

information on assigning other parameters to additional outputs.

4mA1

.00 ppm

20mA1 10.00 ppm

(now 18.84 ma)

(ch1 PV)

Current output menu

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Dissolved Oxygen Controller

Operation

3.2.4.2.2 RELAY CONTACTS

Relay on/off set points are adjusted in this menu. The top line

defines the point in which the relay is energized (on) and the bottom line

defines the point in which the relay is de-energized (off). The LXT-220

can contain up to 6 sets of relay contacts. Refer to Section 3.3.5 Relay

Assignments to set up the number of contacts.

1 On > 10.00 ppm

1. Off < 9.85 ppm

(ch1 PV)

Relay set up menu

3.2.4.2.3 DO LOCUS AND NOISE FILTER SETTINGS

The Locus is the temperature where the different concentrations are

equal and is referenced for temperature compensation. The noise filter

is adjustable from 1 to 20 to dampen any distracting fluctuations on the

sensor

DO Locus

-17.0 ^OC

Noise filter

Electrode Data menu ORP

3.2.4.3 STATUS MENU

This menu allows the user to view the time of day clock and the

engineering information pertaining to the electrode as an informational

screen only. The top line displays the real-time (active) absolute

millivolt value (mVa) the electrode is generating, uncompensated for

temperature variations. The bottom line displays the electrode zero

potential from the last calibration.

This information is extremely helpful in determining the diagnostic

status of an electrode. In conjunction with regular calibrations, the

Electrode Diagnostic Screen provides valuable information to track

electrode performance.

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Input

0 mV

-150.4 mVa

.00ppm

Fri 12:00:37

(volatile)

Electrode Data menu ORP

Time of day clock

3.2.4.4 EXIT/STAY MENU

This menu confirms that the user wishes to leave the section that

they are currently in. This menu will show up each time that the LX-

 Exit  Stay

Exit / Stay menu

220 is prompted to leave the current section before it goes back to the

parameter selection menu. Press the appropriate menu selection key

either to stay in the current section or exit and return to the parameter

selection menu.

3.3 Configuring the LXT-220

To initially configure or reconfigure the instrument, use the left-

side ▲ and ▼ MENU SELECT keys to scroll to the bottom of the

menus list and stop when the CONFIGURE/TRIM option is displayed.

Simultaneously depress the◄ and ► keys to enter the configuration

mode. This mode should be password protected if access to the keyboard

is unrestricted. The new configuration remains in effect through

indefinite power outages.

The configuration mode is a submenu grouping of 9 or more

functions that can be set by the user to tailor the instrument to a

particular application. The following 7 functions appear in groups of 4

for a standard instrument:

PASSWORDS

4-20 ASSIGN

4-20 MANUAL MODE

RELAY ASSIGN/TST

°C/°F & TEMP CAL

4-20 TRIM/TEST

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INPUT A/D CONVERTER TRIM

Some instruments have two channels measuring two unrelated

quantities, and in those cases both channels can be configured from the

same configuration menus.

Depending on options selected 2 additional submenus could appear:

PID ASSIGN

HART ASSIGN

Scroll down to the item of interest, and then simultaneously depress

the ◄ and ► keys to access the sub-menu for that item.

3.3.1 Password Protection

It is worthwhile to become familiar with the password capabilities

of the instrument even if you decide not to use them, as it is possible that

one gets set by mistake and you need to change or erase it.

Password protection can be selectively turned on for the operational

and configuration displays. The operational and configuration passwords

can be different. Passwords are entered using only the right four keys,

and the passwords are numbers consisting only of the digits 1 to 4. No

digits are shown on the keyboard. It is necessary to remember that the

top key is 1, the right key is 2, the bottom key is 3, and the left key is 4.

See Figure 3-2.

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Figure 3-2: Numerical Entry Using Front Panel Keys

After successfully entering the operational password it remains

valid for 60 seconds after exiting the calibration mode on that display.

During that time a second display can be accessed without re-entering

the password. The 60 second timer starts again when exiting the cali-

bration mode on that display also, so that any number of operational

displays can be modified with a single password entry.

If the wrong password is entered three consecutive times in

accessing a protected display all password access is disabled, and the

main display shows “Err PW”. The instrument continues to function

normally, but none of the password-protected settings can be changed.

Normal operation is restored by momentarily turning off power. No

keyboard commands are required to restore normal password protection.

The Err PW display is cleared by any keystroke, but when attempting to

enter a password the display will still show disabled.

If the password is lost and you want to gain access to protected

screens and/or enter a new password, turn off the power, and then reapply

it. Within one second of the time that text first appears on the screen,

press the rightmost key on the keyboard. The screen will go blank to

acknowledge the key press, but there will be no other visible indication

that the key is recognized. After a few seconds the instrument will begin

functioning normally except that the configuration password has been

disabled for 60 seconds. The operational password remains in effect.

Immediately enter the configuration mode and choose a new password.

Note: This method will not work if the key is down at the time

power is applied. The key must be depressed shortly after

text first appears.

The following displays control the password settings.

Operate password level:

no PW

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The protection level for the operational displays is the number on

the left side of the second line. None of the operational displays are

password protected if the protection level is 0. If it is not zero then, with

the exceptions shown in Table 3-1, all displays that affect the operation

of the instrument are protected. An N entry in the table means that the

display is not protected.

Table 3-1: Protection Level Exceptions

level

contrast

man out

1-point buf

3.3.1.1 CHANGING PROTECTION LEVEL

To change the protection level, navigate using the right side

(CALIBRATE) ◄/ ► keys to the old protection level number (3 in the

above screen). Adjust the numerical value using the right side

(CALIBRATE) ▲/▼ keys and then accept the input by pressing either

of the left side MENU SELECT) ▲/▼ keys. The old operational

password is erased if the protection level is changed to 0. Changing from

0 to another value has no effect until a new password is entered. The

display shows no PW if the password has been erased.

3.3.1.2 CHANGING OPERATIONAL PASSWORD

To enter a new operational password, navigate to the old password

(or no PW) using the (CALIBRATE) ◄/ ► keys and select by pressing

both (CALIBRATE) ◄/ ► keys simultaneously. This brings up the new

operational password screen.

New opr password

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Press both (CALIBRATE) ◄/ ► keys again to enter a new

operational password. 1 to 8 digits may he entered. Press either of the

menu keys to accept the new password when done.

Note: A new password will not be accepted unless the protection

level has already been set to a value greater than 0.

3.3.1.3 CHANGING CONFIGURATION PASSWORD

To change the configuration password, use the MENU SELECT

▲/▼ keys to navigate to the PASSWORD menu and select it by

pressing both CALIBRATE ◄/ ► keys simultaneously. Use the MENU

SELECT ▲/▼ keys to bring the cursor to the Configure password level

screen.

Config password level:

no PW

To enter a new configure password, navigate to the old password

(or no PW) using the (CALIBRATE) ◄/ ► keys and select by pressing

both (CALIBRATE) ◄/ ► keys simultaneously. This brings up the new

configure password screen.

New opr password

Press both (CALIBRATE) ◄/ ► keys again to enter a new

configure password. 1 to 8 digits may he entered. Press either of the

menu keys to accept the new password when done.

Note: A new configure password will not be accepted unless the

protection level has already been set to 1.

These two displays work the same as the corresponding operational

displays, except that the protection level can only be 0 or 1.

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The configuration password is rarely used and the configuration

settings are more sensitive, so the password should use more digits than

the operational password. With eight base 4 digits the odds of breaking

the code in three tries are 3 in 65536 if the user knows that there are 8

digits. The user will not know the number of digits that you chose, so

the odds are usually smaller than that. The maximum number of digits

allowed in a password, or the number actually used, cannot be

determined by entering trial passwords. A two or three digit password is

therefore moderately effective if systematic attempts at breaking the

code are not anticipated, but short passwords should nevertheless be

avoided in a critical process.

3.3.2 4-20 mA Output Assignments

The next group of displays are used to assign the 4-20 mA outputs.

Note: The LXT-220 has been configured at the factory for your

specific application as specified at the time of the order.

Using the MENU SELECT ▲/▼ keys, scroll down to the 4-20 mA

ASSIGN option and select it by pressing both CALIBRATE ◄/ ► keys

simultaneously. The screen will display 4-20 1: where . . . is one of the

following selections:

missing

unused

ch1 PV

not installed

Installed but not currently used

Channel 1 process value

Channel 1 temperature

Channel 1 PID controller output

Channel 2 process value

Channel 2 temperature

Channel 2 PID controller output

ch1 temp

ch1 PID

ch2 PV

ch2 temp

ch2 PID

The channel 2 options are only shown on two channel instruments,

and specialized instruments may show additional options.

To change the output assignment, first push both CALIBRATE ◄/

► keys, causing the cursor to move to the right. Then use the right-side

CALIBRATE ▲/▼ keys to scroll through the list of options. The list is

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cyclic. Use either of the MENU SELECT ▲/▼ keys to accept the

selection and move the cursor back to the left. The displayed selection

remains in effect until changed and the selection is remembered through

power outages of indefinite length.

Up to two 4-20 outputs can be assigned to the same source. There is

no error indication if more than two are assigned to the same source, but

there will be no span display for the third. A span display will otherwise

be present in the main menu for each 4-20 output that is assigned to a

source. If the source is associated with channel 2 then the span display

will be in the channel 2 group. The new assignment is not functional

until the setpoints in the span display are set. If a PID controller is

selected as a source then its support displays will also be present.

The next two displays are for the second and third 4-20mA outputs.

Some units do not have all three outputs, but the displays will show

three output options anyway, as the additional outputs can be retrofitted.

The 'missing' assignment should be selected for uninstalled outputs. The

software cannot determine how many 4-20 outputs are installed, so the

'missing' selection might not reflect the actual configuration.

Output #4 is dedicated to HART, and its assignment is discussed in

the HART section. If the instrument is not connected to a HART

network then the fourth output can be used like any of the other outputs.

The fourth output is only present if the instrument was purchased with

the HART option.

A span display will be present in the setup menu for each 4-20

output that is assigned to a source unless the source is a PID controller.

PID controllers have different setup displays, and they are in the same

section. If the source is associated with channel 2 then the display will be

in the channel 2 group. The new assignment is not usable until the

setpoints or PID parameters are specified in the operational displays.

The third line of the display will show a line such as (ch1 man

mode) if an assignable manual mode control is associated with the

output. The line will begin with a question mark if making the current

selection permanent would result in a manual mode assignment conflict.

Refer to Section 3.3.3 Manual Mode Assignment for more information.

3.3.3 Manual Mode Assignment

In the manual output mode, the current output is manually set to the

desired level and saved until changed or released from the manual mode.

The main menu display shows the process value and a 4-20 mA percent

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output field for each channel. The manual mode assignment allows the

percent output display to be associated with any of the 4-20 outputs, in-

cluding the HART output. When in the manual mode the 4-20 output is

controlled from the keyboard. Zero percent corresponds to a current of 4

mA, and 100 percent corresponds to a current of 20 mA. If a 4-20 output

is used to control the process then the manual mode is normally assigned

to that output, although the instrument does not require this choice.

Cross-channel assignments are allowed in that the selected 4-20 can be

assigned to something on the other channel. Cross-channel assignments can

usually be avoided, and they should be avoided when possible.

ch1 man mode on 4-20:

(ch1 PV)

To change the assignment simultaneously depress both

CALIBRATE ◄/ ► keys, then use the right-side CALIBRATE ▲/▼

keys to change the selection. One of the selections is “none”, and with

that selection the percent output field is not present in the operational

display. The bottom line shows the signal that the selected 4-20 is

assigned to. On two channel instruments the next display is the manual

mode assignment for channel two.

Each 4-20 output can have only one manual mode control assigned

to it. If one already exists for the current selection it will be preceded by

a question mark. Some instruments have more than two manual mode

controls in the operational displays, and they must all he assigned to

different 4-20 outputs if they are activated.

The other manual mode controls are built-in in some instruments.

An example would he the weight-percent display of a conductivity unit.

The manual mode field appears in a separate display in these cases, and

it is independent of the manual mode assignments for the main display.

The manual mode capability is automatically activated when a 4-20 is

assigned to one of these functions. The percent output field does not

appear in the operational display unless a 4-20 is assigned to it.

Conversely, when changing the 4-20 assignments a conflict can

arise if a 4-20 with a pre-existing manual mode control is reassigned to

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a function with its own manual mode output. The 4-20 assignment

display will show if the output is associated with an assignable manual

mode. Regardless of the cause, the affected operational display manual

mode fields will begin with a question mark when a conflict exists.

When that happens refer to the manual mode configuration displays, and

HART 1: …..

the question marks there will show where the problem lies.

No contention occurs unless two different displays are actually in

the manual mode for the same 4-20, so the question marks in the

displays can be ignored if the assignments are made for diagnostic

purposes.

3.3.4 HART Output Assignments

If the instrument was purchased with the HART option then the

next five displays are for assigning the HART digital and analog

outputs. The first of these displays is:

where… represents one of the items from the 4-20 mA assignment

list in Section 3.3.2.

HART command #3 requests four variables from the instrument.

Each of these variables can be assigned to any of the sources shown in

the 4-20 assignment section. Each variable has a units code, which

identifies the variable as being pH, millivolts, degrees C, etc. The units

code is supplied automatically depending on the assignment and the

instrument configuration. If command 3 is not used then only the first

output assignment will be reported. If any output is assigned to

“missing” or “unused” then that value will be reported as “not a

number”, and the units field will be “not used”.

HART analog 1:

The first digital output assignment is referred to as the primary

variable in the HART system.

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HART analog 2:, HART analog 3:, HART analog 4:

The next three displays assign the second, third, and fourth

variables. The assignments are changed in the same way as for the 4-20

outputs. See Section 3.3.2 4-20mA Output Assignments.

It is not possible to assign more than one HART digital output to

the same source. The current selection will be preceded by a < symbol

on the display if making it permanent would result in duplication.

HART analog: 5

4-20 output #4 is dedicated to HART. This output normally carries

the digital information superimposed on the 4-20 mA current. But if the

HART system uses the multi-drop mode then the current output of 4-20

#5 is disabled, with only the digital signal remaining. Several instruments

are connected in parallel in the multi-drop mode, so analog signaling is

not possible. The current that would have been output is still reported

digitally, as a percentage, and that will be sufficient for some applications.

But if an actual 4-20 current is required then one of the other 4-20 outputs

must be used to supply it, and this display is used to make the assignment.

The specified 4-20 must in turn be assigned to an appropriate source.

Note: If the HART analog output is assigned to an output other

than #5, then #5 cannot be assigned to anything. It must

be set to “missing” or “unused”.

The span settings for the selected 4-20 output correspond directly to

the HART lower and upper range limits, and they can be set either from

the keyboard or with command #35. If they are changed with the

command then the new value will be shown on the instrument's span

display for the selected output. If they are changed from the keyboard

then those values are reported digitally over the HART network.

If command 35 is to be used to set the limits then the HART 4-20

output must be selected first because the output span does not exist until

an assignment is made. The span settings must be readjusted or be

resent when the HART analog output assignment is changed.

The 4-20 supplying the HART analog output is normally assigned

to the same source as the primary variable, and the HART displays show

the engineering units for the upper and lower range limits as being the

same as those of the primary variable. It is possible to assign the analog

output to other sources, but other assignments are non-standard, and the

units displayed by the remote system will not be correct.

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If the 4-20 selected for the HART analog output is assigned to

“missing” or “unused” then the digital representation of the output

current will be “not a number”, but with up to four digital variables still

being transmitted.

3.3.5 Relay Assignments

The next 8 displays are for the relay assignments. The first of the

relay displays is:

Relay 1: ...

Where ... represents an item from the same list that is used for the

4-20 assignments. The procedure for selecting a relay assignment is the

same as for the 4-20 outputs. See Section 3.3.2 4-20mA Output

Assignments.

Up to two relays can be assigned to the same source, so one relay

can be used to control the process, and another relay can be used as an

alarm if the process value is out of limits.

The relay configuration menu provides for 8 relays, but most units

do not have that many relays installed. Some units do not have any

relays installed, but the relay menu will nevertheless be present as the

relays can be retrofitted. The software cannot determine how many

relays are actually present, so the “missing” selection might not reflect

the actual configuration.

A display showing the relay setpoints for each relay is present in the

main menu. If the relay is assigned to a channel 2 function then the display

will be in the channel 2 group. The display is not shown if the “missing” or

“unused” selection is made. A new relay assignment is not necessarily

functional until the setpoints in the span display are set. If a PID controller

is selected as a source then its support displays will also be present.

3.3.6 Temperature Calibration

The next display is for calibrating the process temperature

displayed by the instrument.

Trim ^OC

Unit

25.0^OC

Temperature Calibration

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The bottom line shows the measured temperature. To change the

displayed temperature so it agrees with a measured value, place the

cursor on the top line then simultaneously depress both CALIBRATE

◄/ ► keys. Use the right-side CALIBRATE ▲/▼ keys to adjust the

number so that the displayed temperature agrees with that measured by a

thermometer.

The number shown on the top line is simply added to the

temperature that the instrument measures. There is no slope correction.

To toggle between degrees C and degrees F, place the cursor on the

bottom line and simultaneously depress both CALIBRATE ◄/ ► keys.

This will change the unit. Press both keys again to toggle back to the

original unit.

All temperature displays on both channels use the selected system

of units. The scale and units code in the HART temperature output is

also controlled by this selection.

On two channel instruments the next display trims the channel 2

temperature.

3.3.7 4-20 Trim

The next six displays are used to trim the 4-20 outputs. The 4-20

outputs are calibrated at the factory and will never need recalibration in

most applications. Periodic recalibration is not recommended.

4mA1 trim

.000

4 to 20 mA trim

As in the other menus, the cursor moves to the right when both

CALIBRATE keys are depressed and the output current is set to 4.00

mA, overriding the output assignment. Measure the 4-20 output #1

current with an ammeter, and adjust the number on the top line until the

meter reads 4.00 mA.

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The next display is for trimming the 20 mA point of output #1 and

it works the same as the 4 mA trim. The 4 mA and 20 mA trims do not

interact, and the endpoint trims are linearly interpolated for other output

values.

Note: The 4-20 #5 output must be trimmed by standard

commands sent over the HART communication link.

3.3.8 Input A/D Converter Trim

This display is used to calibrate the analog to digital converter that is

used to measure the process value. The bottom line shows the measured

input voltage. The scale factor on the top line is adjusted until the

displayed voltage is the same as that of a voltmeter connected to the input.

If the process is stable then the voltage can be the output of a sensor, but it

is better to replace the sensor with a fixed voltage source. For optimum

accuracy, the calibration voltage should be a substantial portion of the full

scale voltage. It can be of either polarity. The input zero point error is

automatically removed, so there is no adjustment for it.

1 in gain

400.0 mV

1.0000

Input A/D converter trim

The normal input range is +/- 600 millivolts, but ORP and some

specific ion units use a +/-1200 millivolt range. On conductivity units

the analog voltage is not externally accessible, but conductivity systems

do not have millivolt displays, so no calibration is required. On

conductivity units this display is only used for factory testing.

The input scale factor is calibrated at the factory and will never

need recalibration in normal applications. Periodic recalibration is not

recommended, as most units will remain accurate to within about 0.2

percent for many years. Further, any inaccuracy in the displayed

millivolts is calibrated out when buffer calibrations are performed, so

there is no requirement that the displayed millivolts be highly accurate.

If the scale is accidentally changed and it is not convenient to perform a

voltmeter calibration then simply set the scale factor to 1.0000. Most

units are accurate to 2 percent with that setting, which is adequate for

most applications.

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On two channel units the next and last display is for trimming the

channel 2 analog input.

3.3.9 PID Assignments

Two independent Proportional Integral Derivative (PID) controllers

are available as options on all instruments, including one channel units.

The sub-menu for assigning the controller inputs is:

PID A: …..

PID B: …..

Where . . . . represents one of the items from the 4-20 mA

assignment list in Section 3.3.2. The PID controller outputs in turn

represent separate signal sources, and various outputs can be assigned to

them.

Not all signal sources are suitable as inputs to a PID processor, and

an asterisk on the display marks the selections that are unavailable.

Potentially useful sources, such as the process value, temperature, and

quantities derived from the measured process value(s) are normally

available. The assignment should be set to “unused” if no controller is

needed. This will prevent the PID setup displays from appearing in the

operational section.

Either PID processor can be assigned to a signal from either

channel, and they can both be assigned to signals on the same channel,

but they cannot be assigned to the same signal on the same channel. The

current selection will be preceded by a question mark on the display if

making it permanent would result in duplication.

Up to two 4-20 mA outputs and up to two relays can be assigned to

each PID processor output. The output of the PID processor is discarded

if nothing is assigned to it.

If a 4-20 mA output is assigned to a PID processor there will be no

display for it in the setup section of the operational displays, as the 4-20

output scaling is fully specified by the PID setup parameters in the same

section. If relays are assigned to a PID output there will be setpoint

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displays for them in the setup section, and they can be used for alarm

purposes or otherwise. The bottom line of the display will identify the

relay as being assigned to a PID output, and it will also show what the

input to the PID processor is assigned to.

A 0% relay setpoint refers to the minimum PID output, which

corresponds to a current of 4 mA on any current loops assigned to the

PID, and a 100% setpoint corresponds to a 20 mA current. When 4-20

mA outputs are assigned to a PID output, it is helpful to assign one of

the manual mode displays (Section 3.3.3) to one of the them so that the

percent output of the controller will be visible in the operational

displays.

See Section 3-5 Proportional Control Setup and Configuration for

configuring and setting up the optional PID control feature.

3.4 Calibration

Calibration involves performing either a one-point standardization

calibration or two-point span calibration. These choices are available

after choosing BUFFER from the Parameter Selection Menu

3.4.1 Manual Output Mode

In order to perform calibrations without interfering with control or

recorder functions, the LXT-220 incorporates a manual output mode. In

the manual output mode, the current output is set to the desired level and

saved until changed or released from the manual mode. On LXT-220s

with the optional PID controller output on channel 2, the current output

displayed is the PID controller output. The following procedure

demonstrates the use of the manual output.

Note: Prior to any calibration, The LXT-220 controller should be

placed into the manual mode

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M 50.0%

7.80

25.0^OC

Main Menu, DO

Procedure:

1. If not at the Main Menu, press the appropriate MENU

SELECTION key to reach the Main Menu.

2. Press both horizontal ◄►CALIBRATE keys simultaneously to

enter the calibrate mode and observe the "M" appearing in front

of the % current output value. The "M" signifies that the manual

output is locked in the manual mode.

3. Using the horizontal CALIBRATE keys one at a time, position

the cursor under the digit to be adjusted.

4. Increase or decrease the value by pressing the appropriate

vertical ▲/▼ CALIBRATE key.

To release manual output:

1. Return to the Main Menu by pressing the appropriate MENU

SELECTION key.

2. Observe that the "M" appears in front of the % current output

value. This "M" signifies that the transmitter output is in

manual.

3. Press only the left-hand ◄ CALIBRATE key and observe the

"M" disappear, releasing the LXT-220 from the manual output

mode. The % output value will return to the real-time current

output.

3.4.2 Parameter Selection Menu

Scroll down from the main menu to reach the parameter set up

menu. Once in the Parameter set up menu select the function you would

like to enter.

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Buffer

Setup

Status

• BUFFER: Perform a 1 or a 2 point calibration

• SETUP: Set up the range of the 4-20 mA output

• STATUS: Information only. Shows the data stored from the last

calibration.

3.4.2.1 BUFFER MENU

From the parameter selection menu chose the top line (the

BUFFER command) and press the two horizontal ◄► CALIBRATE

keys simultaneously to enter the BUFFER calibration submenu. Both

the one-point calibration (standardize) and the two-point (span)

calibrations are available within this menu. The procedures for each

calibration function are given below.

3.4.2.2 ONE-POINT BUFFER CALIBRATION (STANDARDIZE)

Because all dissolved oxygen electrodes experience minor

variations, buffer calibrations are necessary before installing the

electrodes in service. Also, occasional calibrations are necessary to

compensate for electrode degradation while in service. For

measurement specifics refer to the dissolved oxygen sensor manual.

1DO

Cal

.00 ppm

.0 mV

Standardization menu pH

Procedure:

1. Be sure that the cursor is located under the "1" as illustrated.

2. For diagnostic reasons note the ppm and mV values from the

prior calibration.

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3. Clean the electrode and insert the sensor into the desired buffer.

4. Press both horizontal CALIBRATE keys simultaneously to enter

the calibrate mode. Observe the diagnostic value on the bottom

line change from historical data to a real-time value and that the

term "CAL" has disappeared.

5. To change the buffer point, position the cursor under the desired

digit using the left-hand CALIBRATE key.

6. Increase or decrease the value by pressing the appropriate

vertical CALIBRATE key.

7. Wait for the real-time mV value to stabilize.

8. To save the calibration and exit the calibrate mode, press either

MENU SELECTION key.

A perfect electrode slope (efficiency) is typically greater than -150.

mV/FS. If the value falls below -100.0 mV/FS, the electrode should be

serviced or replaced.

3.4.2.3 TWO-POINT BUFFER CALIBRATION (SPAN)

When first installing an electrode, the second cal point

establishes the slope variations or efficiency. The span is typically done

in air which is the saturation point of the solution when in equilibrium.

2DO

Cal

8.40 ppm

-173.8 mV/FS

Span calibration menu pH

Procedure:

1. Perform a one-point calibration as outlined in Section 3.4.2.2.

2. Press the appropriate MENU SELECTION key to reach the

Electrode Span Menu and locate the cursor under the "2" as

illustrated.

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Operation

LXT-220 DO

3. For diagnostic reasons note the DO and mV/FS values from the

prior calibration.

4. Press both horizontal CALIBRATE keys simultaneously to enter

the calibrate mode. Observe the diagnostic value on the bottom

line becomes a real-time value and that the term "CAL" has

disappeared.

5. To change the buffer point, position the cursor under the desired

digit using the left-hand CALIBRATE key.

6. Increase or decrease the value by pressing the appropriate

vertical CALIBRATE key.

7. Wait for the real-time mV value to stabilize.

8. To file the calibration and exit the calibrate mode, press either

MENU SELECTION key.

A perfect electrode slope (efficiency) is typically greater than -

150.0 mV/FS. If the value falls below -100.0 mV/FS, the electrode

should be serviced or replaced.

IMPORTANT:

If a flashing asterisk appears during or after

calibration, the electrode may require service, or

the buffer solution may be contaminated.

Note: Comparing the millivolt values before and after the

calibration provides a valuable diagnostic tool in

determining the degradation of the electrode. Large

differences between calibrations may indicate coating or

damage to the measurement half-cell.

3.4.2.4 CALIBRATION USING A GRAB SAMPLE AS A STANDARD

The LXT-220 allows easy standardization to a grab sample value

by placing the process value into the first calibration point.

Procedure:

1. Record the O₂value of the process when the sample is extracted.

2. Record the O₂value of the grab sample.

3. Calculate the difference between the two values as follows:

(Grab sample value) - (Displayed value) = differential

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Operation

4. Immediately before making the calibration adjustment, note the

current value on the display and add the differential to the

current value. This "total adjusted" value is entered as the buffer

value.

3.4.2.5 CALIBRATION ERROR DETECTION & ELECTRODE OPERATIONAL

GUIDELINES

If the slope calibration performed in Section 3.4.2.3 is not within

the predetermined limits of the instrument, a flashing asterisk (*) will

appear.

The presence of the asterisk indicates a potential calibration

problem. In general, if the asterisk appears, the integrity of the

electrode, the buffer solutions or the handling procedure should be

questioned. See the dissolved oxygen sensor manual for specifics on the

electrode.

3.4.2.6 BACK-TO-FACTORY CALIBRATION

This feature allows the LXT-220 to be reset to "typical electrode"

for electrode potentials. As the electrode ages it will deteriorate and the

mV/FS will decay and will eventually require replacement. If the

membrane is torn or coated the calibration will be either sluggish or out

of range.

The following procedure for returning the LXT-220 to factory

calibration can be used for both standardize and span calibrations.

1 DO

Cal

.00 ppm

.0 mV

2 DO

Cal

10.0 ppm

-157.5 mV/FS

Standardization menu DO @ factory default

settings

Standardization menu @ factory default

settings

Procedure at the Standardization Menu:

1. Position the cursor under the "C" in "Cal."

2. Press both horizontal CALIBRATE keys simultaneously and

observe the cursor briefly move to the right. The default setting

is complete.

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Operation

LXT-220 DO

3. This procedure is required at BOTH of the calibration points.

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Maintenance

4.1 Routine Maintenance

Aside from normal cleaning routine maintenance is limited to

recalibration. For recalibration, see Section 3.4 Calibration. However, if

service of the internal components is required always turn off the power

to the instrument.

4.1.1 Cleaning

Although the LXT-220 NEMA 4X enclosure can withstand harsh

environments, it may become necessary to clean the front panel if it

becomes coated or dirty. Cleaning the front panel can be performed

with a detergent and water.

CAUTION:

DO NOT USE ACETONE, ACIDS OR CAUSTIC

SOLUTIONS ON THE ENCLOSURE SURFACE.

Before cleaning, the integrity of the enclosure seals should be

inspected. Also check the conduit fittings and seals to make sure

moisture does not enter the enclosure while cleaning.

If the enclosure cover must be removed, it is wise to clean and

inspect the gasket seal. If the seal is damaged, replace the gasket.

Always keep the gasket lightly lubricated with a silicone grease.

4.1.2 Replacement of the Microprocessor:

For replacement of the microprocessor, contact the factory.

CAUTION:

NEVER INTERCHANGE EPROMS FROM ONE

TRANSMITTER TO ANOTHER. DOING SO WILL

AFFECT TRANSMITTER PERFORMANCE.

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Maintenance

LXT-220 DO

Table 4-1: Troubleshooting

SYMPTOM

POSSIBLE CAUSES

SUGGESTED

ACTION

The LCD does not

display.

No power to the

instrument.

Check power supply

to be sure the correct

voltage is being

supplied to the

transmitter.

Contrast level is set

too low.

Set contrast level to a

higher value.

Because the contrast

menu is always the

top menu, it can be

reached by pressing

the upper MENU

SELECTION key at

least 12 times. Enter

the calibrate mode

and increase the

value.

Sensor or signal

conditioner has a

short that draws too

much power from the

transmitter.

Check the sensor for

proper operation. To

verify, disconnect all

sensor wires and

cycle power off, then

on.

The PROM has not

been properly

Check orientation of

the PROM to the

installed in the socket. socket. Make sure the

pins are fully inserted

and are not bent.

Readings are not

linear at the low end

of the range.

The sensor range is

not compatible with

the instrument.

Verify the sensor

range. Install a

sensor with the

correct range.

Erratic readings.

Air bubble in sensor.

Check orientation of

sensor.

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Dissolved Oxygen Controller

Appendix

A.1 Specifications

Packaging: NEMA-4X weatherproof enclosure

suitable for general purpose application

Power Requirements: 115/220 VAC or optionally 24 VDC 0.25A

Display: Menu driven Supertwist LCD.

Simultaneously displays process ID,

Process value in Eng. units, % output and

temp in °C or °F.

Sensor: Application specific

Input Measurement Parameters:

Conductivity, Resistivity, pH, Specific

Ion, Dissolved Oxygen, ORP.

Also, external events and analog inputs

can be integrated logically or operational

modifiers.

Outputs: 4-20 mA, HART or RS232 up to a

maximum of 6 analog outputs.

Response Time: 90% of step change in 1 second

Accuracy: ±0.10% of full scale

Linearity: ±0.05% of full scale

Sensitivity: ±0.05%

Stability: ±0.2% per year @ 0 to 70°C

Repeatability: ±0.1%

Input/Output Isolation: Max 300V between process input and any

4-20mA output

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LXT-220 DO

Maximum Loop Impedance: 800Ω on 4-20 outputs with internal

24VDC

Digital Interface: HART option

Operating Temperature: -4° to 158°F (-20° to 70°C)

Dimensions: 5.67” H, 5.67” W, 6.97” D

Temp. Compensation: Automatic, -30 to 140°C, RTD. Accuracy

within ±1.0°C over a 0-100°C span.

50/60Hz Noise Rejection: Greater than 70 db.

Calibration: Auto calibration allows the definition of

two calibration points, saved in memory,

during the initial startup. This will allow

subsequent standardization and span

calibrations with only 2 keystrokes. Cal

parameters initiated by configuration

settings.

Configurability: Parameter graph. Relays (up to 8) solid

state or SPDT mechanical, 8 internal

clocks and timers (one-shot and periodic),

4 current outputs (4-20mA) and 2 PID

current outputs, logical function (and/or

gates) can all be setup as desired in the

configuration menus.

5A switching mechanical relays, .065-3A

230VAC solid state with 600 W total load

without additional heat sinking

precautions.

Password Protection: Multilevel password configuration allows

selection of protected parameters in

operational and/or configuration routines.

Sentinel Compatible: 2 channels

Conc. Curves: Built-in for conductivity measurements:

HCl, H₂SO₄, NaOH, NaCl, HF, HNO₃,

KOH, etc.

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Appendix

A.2 Model Designation

The standard LXT-220 controller is 110VAC powered unit in a 1/2

DIN, NEMA 4X enclosure. It incorporates a backlit graphics display and

a membrane keypad. This instrument requires an external 24VDC to

power the outputs. An option is available for an internally generated

24VDC powered instrument.

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-220

LXT-220 controller

Channel 1 Input:

ORP Oxidation Reduction Potential (REDOX)

DO Dissolved Oxygen (specify ppm or %)

PION Specific ion

CDL Conductivity, Low range (20uS or less)

CDH Conductivity, High range (50uS to 50mS)

CDT Conductivity Toroidal (electrodeless greater then 50mS)

Channel 2 Input:

PH pH

ORP Oxidation Reduction Potential (REDOX)

DO Dissolved Oxygen (specify ppm or %)

Resistivity (0 to 50 megohms)

PION Specific ion

CDL Conductivity, Low range (20uS or less)

CDH Conductivity, High range (50uS to 50mS)

CDT Conductivity Toroidal (electrodeless greater then 50mS)

Resistivity (0 to 50 megohms)

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LXT-220 DO

Channel 3 Input:

Input from an external 4 to 20mA device

EX1 Input from an external relay contact device

* Sentinel Diagnostic:

DIAG1Sentinel Diagnostic on channel 1

DIAG2Sentinel Diagnostic on channel 2

** Number of 4 to 20 mA Outputs:

1mA One 4 to 20mA Current Output

2mA Two 4 to 20mA Current Outputs

3mA Three 4 to 20mA Current Outputs

4mA Four 4 to 20mA Current Outputs

5mA Five 4 to 20mA Current Outputs

6mA Six 4 to 20mA Current Outputs

Hart

Hart protocol option

Type of relay contacts:

SOLID STATE 240VAC 3amp

Form C (SPDT)

Number of relay contacts:

Two relay contacts

Four relay contacts

Six relay contacts

Eight relay contacts

Mounting hardware:

UM Universal mounting plate

PM Panel mounting hardware

HM Handrail mounting plate (including 2” hardware)

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Appendix

Optional power requirements:

PS1 Standard powered by 120VAC

PS2 24 VDC internally generated to power the 4 to 20 mA

output cards

PS3 LXT-220 controller powered by 24 VDC

Special options:

F2 Output = function of dual inputs: ratio, free chlorine,

differential, average: SPECIFY!

***%C Percent (%) ion concentration display only

(Available for Conductivity only)

Signal conditioner mounted inside transmitter enclosure.

Field selectable time average (2 to 32 seconds)

Periodic timer

One-Shot timer

Logic Gates Field configurable

Special temperature input from sensor 1000 ohm pt

PID 3 mode proportional control

TPC Time Proportional Control (Requires 2 solid state relay

contacts)

GO2 Gaseous Oxygen (O2)

For options not listed, consult factory for price and availability.

Diagnostic Feature is only available on pH, ORP, and

Pion. If the diagnostic option is selected the sensor and

electrode must also contain the diagnostic option for the

feature to function.

4 to 20mA Current outputs are field configurable. If the

outputs are to be configured by Teledyne at time of

shipment the output parameters must be specified. If not

specified the outputs will be configured as standard 4 to

20mA outputs corresponding to the specified input.

***

If an output is required along with the display a second

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Appendix

LXT-220 DO

output must be specified.

Output configuration options:

MA 4-20 mA, standard

TMP 4-20 mA, Temperature (adjustable -100 to +200°C)

PID 4-20 mA, 3 mode control

% (ion) mA % concentration for display and 2nd output

(Conductivity only)

DIAG Sentinel Reference Diagnostic

As an example:

MODEL NUMBER EXAMPLE:

LXT-220-PH/MA-PS2-UM

This indicates the LXT-220 Controller for pH applications with a

standard single 4-20mA output. The controller has an internal 24 VDC

power supply to power the output card. The instrument is equipped with

a universal mounting plate.

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Index

A to D converter trim, 42

AC power. See power

accuracy, 42, 53

address, 55

air, 47

current output, 26

configure, 28

decreasing a value, 16

dedicated output, 39

default parameters, 14

diagnostic feature, 59

digital interface, 54

digital signal, 39

alarm, 13, 15

HI, 13

LO, 13

alarm relay, 40

dimensions, 54

analog to digital converter, 42

ASSIGN, 35

display, 14, 16, 53

display contrast, 25

assigning parameters, 28

assignment conflict, 36, 37

auto calibration, 54

automatic calibration, 14

back to factory calibration, 14, 22, 49

backlit graphics display, 57

BUFFER, 27, 44, 46

CALIBRATE key, 16, 23

numerical equivalence, 31

calibrate mode, 23

calibration, 22, 44

calibration menu, 27

calibration voltage, 42

caution sign, iv

change the protection level, 33

changing output assignment, 37

cleaning, 51

dissolved oxygen, 13, 14, 24, 53

dissolved oxygen electrode, 46

dual channel input, 22

dual input. See input

dual input option, 13

efficiency, 47

electrical connections, 20

electrode, 29

electrode degradation, 22, 46

electrode diagnostic screen, 29

electrode failure, 14

electrode performance, 29

electrode potential, 22

electrode slope, 47, 48

electrode variation, 46

enclosure. See NEMA-4X

Err PW, 32

command #3, 38

erratic reading, 52

command #35, 39

error detection, 49

concentration curves, 54

conductivity, 13, 14, 53

conduit, 21

EXIT/STAY MENU, 30

external event, 53

factory calibration point, 22

feature codes, 57

conduit hole, 17

configuration password. See password

CONFIGURE/TRIM, 30

configuring LXT-220, 30

connections, 17

features, 14

figures listing, ix

flashing asterisk, 49

front panel, 16

contrast, 52

gasket, 51

contrast menu, 24, 25

grab sample, 48

gray screen, 25

cross-channel assignment, 37

HART, 14, 15, 28, 36, 38, 40, 53, 54

HART analog output, 39

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LXT-220 DO

HART assignment, 38, 39

hysteresis, 15

hysterisis, 13

opening the front panel, 20

operating temperature, 54

operation, 23

impedance, 54

incrementing a value, 16

input, 13, 27

operational password, 32

options, 14

ORP, 14, 22, 42, 53

output, 13, 28

conditioned, 21

dual, 14

analog, 53

input range, 42

assignment, 35

installation, 19

averaged, 15

internal clock, 54

configure, 28

internal layout, 17

internal power supply, 15

isolation, 53

keyboard control, 37

LCD. See display

correspondence, 22

current, 14, 36, 54

current, adjust, 26

dirrerential, 15

floating, 15

linear, 28

linearity, 53

graphic display, 26

isolated, 15

locus, 29

multiple, 15

low level DC signal, 17

main menu, 24, 26

manual mode, 26, 37

manual mode assignment, 37

manual output mode, 22, 36, 44

manuals, additional, v

measurable parameter, 22

membrane, 22, 49

membrane switche. See switch

menu options, 24

PID, 15, 43, 54

ratio, 15

signal factory assignment, 17

output configuration options, 60

oxidation-reduction potential. See ORP

panel mounting, 20

parameter selection menu, 27, 45

password, 31, 54

configuration, 34

operation, 33

MENU SELECT key, 16, 23

menus, 24

percent output display, 37

pH, 14, 53

microprocessor, 13

microprocessor replacement, 51

missing assignment, 36

model designation, 57

mounting bracket, 20

mounting plate

PID, 13, 15, 28, 36, 40, 43

minimum output, 44

PID assignment, 43

plot function, 28

power, 17, 21, 53

pre-pHault diagnostics, 14

primary variable, 38

probe, 13

handrail, 20

universal, 19

multi-bus architecture, 13

multi-drop mode, 39

NEMA 4X, 57

NEMA-4X, 14, 17, 20, 53

no display, 52

process control, 13, 40

process variable display, 26

proportional band, 15

protection level, 32, 34

question mark, 36, 37, 43

rate, 15

noise filter, 29

noise rejection, 54

non-linear reading, 52

numeric adjustments, 16, 23

one point calibration, 22

one-point calibration, 44, 46

relay, 15, 29, 54

configure, 28

relay assignment, 40

relay configuration menu, 40

relay output, 13

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Index

relay setpoints, 40

release manual output, 45

repeatability, 53

STATUS, 27, 46

STATUS menu, 29

submenus, 24

reset, 15

Supertwist, 53

resistivity, 13, 14, 53

response time, 53

restore password, 32

reverse acting, 13, 14

routine maintenance, 51

RS232, 53

safety information, iv

saturation point, 47

scale factor, 42

switch, 14, 16

tables listing, x

technician symbol, iv

Teledyne address, 55

temperature calibration, 40

temperature compensation, 54

temperature control, 13

temperature conversion, 14, 41

terminal block, 17

timer, 32, 54

sensitivity, 53

sensor

trim, 41

SP1 & SP2, 21

troubleshooting, 52

two point calibration, 22

two-point calibration, 44, 46

typical electrode, 22, 49

U-bolt, 20

undisturbed output, 26

warning sign, iv

warranty, ii

sensor orientation, 52

sensor wiring, 22

serial number, iii, 24

SETUP, 27, 28, 46

shipping damage, 19

slope variation, 47

software, 15

software version, 24

span calibration, 22, 44

span display, 36

weatherproof, 53

web address, 55

website address, v

white screen, 25

span setting, 39

specific compensation, 14

specific ion, 13, 14, 42, 53

specifications, 53

stability, 53

wiring, 21

wiring label, 17, 21

zero electrode offset, 14, 22

zero potential, 27, 29

standardization, 22, 44, 46

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