YOKOGAWA FLXA402 User manual

User’s
Manual Model FLXA402
4-Wire Converter
Opeartion of pH/ORP
IM 12A01F02-01EN
IM 12A01F02-01EN
1st Edition

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IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
uIntroduction
Thank you for purchasing the FLXATM402 4-Wire Converter.
This Instructor’s Manual contains all essential information for the user to make full use of
FLXA402.
Please read the following respective documents before installing and using the FLXA402.
The related documents are listed as follows.
General Specications
Contents Document number Note
FLXA402 4-Wire Converter GS 12A01F01-01EN Online manual
“EN” in the document number is the language code.
User’s Manual
Contents Document number Note
FLXA402 4-Wire Converter
Start-up and Safety Precautions IM 12A01F01-01EN Attached to the product (printed manual)
FLXA4024-Wire Converter
Installation and Wiring IM 12A01F01-02EN Online manual
FLXA402 4-Wire Converter
Operation of Converter IM 12A01F01-03EN Online manual
FLXA402 4-Wire Converter
Operation of pH/ORP IM 12A01F02-01EN Online manual (This manual)
FLXA402 4-Wire Converter
Operation of SC IM 12A01F03-01EN Online manual
FLXA402 4-Wire Converter
Operation of ISC IM 12A01F04-01EN Online manual
FLXA402 4-Wire Converter
Operation of DO IM 12A01F05-01EN Online manual
“EN” in the document number is the language code.
An exclusive User’s Manual might be attached to the products whose su󰀩x codes or option
codes contain the code “Z” (made to customers’ specications). Please read it along with this
manual.
Technical Information
Contents Document number Note
FLXA402 4-Wire Converter
HART communication TI 12A01F01-61EN Online manual
FLXA402 4-Wire Converter
Modbus communication TI 12A01F01-62EN Online manual
“EN” in the document number is the language code.
You can download the latest documents from our website. Scan QR code.
http://www.yokogawa.com/an/xa402/download/
Media No. IM 12A01F02-01EN 1st Edition : Nov. 2018 (YK)
All Rights Reserved Copyright © 2018, Yokogawa Electric Corporation

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IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
n Notes on Handling User’s Manuals
• Please provide the user’s manuals to your end users so that they can keep the user’s
manuals for convenient reference.
• Please read the information thoroughly before using the product.
• The purpose of these user’s manuals is not to warrant that the product is well suited to any
particular purpose but rather to describe the functional details of the product.
• No part of the user’s manuals may be transferred or reproduced without prior written
consent from YOKOGAWA.
• YOKOGAWA reserves the right to make improvements in the user’s manuals and product at
any time, without notice or obligation.
• If you have any questions, or you nd mistakes or omissions in the user’s manuals, please
contact our sales representative or your local distributor.
n Drawing Conventions
Some drawings may be partially emphasized, simplied, or omitted, for the convenience of
description.
Some screen images depicted in the user’s manual may have di󰀨erent display positions or
character types (e.g., the upper / lower case). Also note that some of the images contained in this
user’s manual are display examples.
n Composition of this User’s Manual
FLXA402, a modular-designed converter, is a multi- parameter instrument o󰀨ering a wide
range of measurement choices; such as: pH/ORP (oxidation-reduction potential), Resistivity/
Conductivity (SC), Inductive conductivity (ISC), Dissolved Oxygen (DO) – with the respective
sensor module.
This user’s manual contains general description and precautions of the instrument.
The table below shows user’s manuals to read concerning the instrument’s operation,
conguration, or calibration, which vary depending on its installation, wiring, and specication of
each instrument.
Contents pH/ORP
SENCOMTM SA
Contacting
conductivity (SC)
Inductive
conductivity (ISC)
Dissolved oxygen
(DO)
Introduction and
general description IM 12A01F01-02EN
Wiring and installation IM 12A01F01-02EN
Converter operation
(Setting, Calibration)
Maintenance,
Troubleshooting
IM 12A01F01-03EN (This manual)
Sensor operation
(Setting, Calibration) IM 12A01F02-01EN IM 12A01F03-01EN IM 12A01F04-01EN IM 12A01F05-01EN
n Trademark Acknowledgments
• FLEXA, FLXA, SENCOM and FieldMate are trademarks or registered trademarks of
Yokogawa Electric Corporation.
• All other company and product names mentioned in this user’s manual are trademarks or
registered trademarks of their respective companies.
• We do not use TM or ® mark to indicate those trademarks or registered trademarks in this
user’s manual.

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IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
n Terminology
sensor(s): sensors, sensors with SA11, sensor module(s)
SENCOM SA SA11, SENCOM Smart Adapter or “-S5” (SENCOM SA) of 1st or
2nd input
analog sensor (module) selectable sensors when -P1/-C1/-C5/-D1 is specied for 1st
or 2nd input, e.g. PH8E�P, PH4�, OR8E�G, SC4AJ, SC8SG,
SC210G, ISC40GJ, ISC40SJ, DO30G.
multiple sensor connection multiple sensor connection via BA11 junction box when “-S5”
SENCOM SA is specied for 1st input
Optical DO Sensor, DO70G ”-D5” (Digital sensor”) for 1st input
NE107: NAMUR NE107
see the section 4-30 ペペペペペ4.7 Error settingsペ in IM
12A01F01-03EN Operation of Converter
ID chip Sensors with ID chip are selectable when "-S5" SENCOM SA is
specied for 1st or 2nd input, such as PH8E�P••• V, FU20-VS
sensor connection number e.g.1-1. Note that this is NOT display name.

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IM 12A01A02-01E 1st Edition : Nov. 22, 2018-00
Model FLXA402
4-Wire Converter
Operation of pH/ORP
CONTENTS
IM 12A01F02-01EN 1st Edition
uIntroduction....................................................................................................i
1. Sensor Menu Outline ............................................................................... 1-1
2 Sensor menu............................................................................................. 2-1
2.1 Detail................................................................................................................... 2-2
2.2 Calibration ......................................................................................................... 2-9
2.3 Reset wellness .................................................................................................. 2-9
2.4 Reset ................................................................................................................ 2-10
2.5 Sensor settings ............................................................................................... 2-10
3. Sensor setting........................................................................................... 3-1
3.1 Congure sensor .............................................................................................. 3-2
3.1.1 Sensor type (A) .................................................................................. 3-2
3.1.2 Temperature settings ......................................................................... 3-2
3.1.3 Others ................................................................................................ 3-3
3.2 Measure setting................................................................................................. 3-4
3.2.1 Temperature settings ......................................................................... 3-4
3.2.2 Temp compensation........................................................................... 3-4
3.2.3 pH....................................................................................................... 3-5
3.2.4 ORP ................................................................................................... 3-6
3.2.5 High/Low alarm setting ...................................................................... 3-6
3.3 Calibration settings .......................................................................................... 3-7
3.3.1 Cal. set pH.......................................................................................... 3-7
3.3.2 Cal. set ORP/rH ................................................................................. 3-8
3.3.3 Cal. Set others ................................................................................... 3-9
3.3.4 Cal. set temperature .......................................................................... 3-9
3.4 Wellness settings............................................................................................ 3-10
3.4.1 Impedance settings.......................................................................... 3-10
3.4.2 SENCOM sensor status................................................................... 3-11
4. Calibration pH/ORP .................................................................................. 4-1
4.1 pH Calibration.................................................................................................... 4-2
4.1.1 pH Manual.......................................................................................... 4-2
4.1.2 Automatic Calibration......................................................................... 4-4
4.1.3 Sample Cal......................................................................................... 4-6
4.2 Cal. set ORP/rH.................................................................................................. 4-7
4.3 Temperature Cal. ............................................................................................... 4-7
Appendix 1 For pH/ORP......................................................................... App.1-1

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Revision Record.......................................................................................................i

<1. Sensor Menu Outline> 1-1
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
1. Sensor Menu Outline
Main/Home screen > “Sensor menu”. > “Detail” / “Calibration” / “Setting”
The operation is secured by password. See the section 5.4 in IM 12A01F01-03EN Operation of
Converter.
Figure 1.1 Sample image of “Sensor menu”
n Sensor detail
On Sensor menu, tap “Detail”. Read 2.1.
Figre 1.2 Sample image of “Detail”(Sensor menu>Detail)
nCalibration
On Home/Main screen, tap . On Sensor menu, tap for calibration of sensors.
Figure 1.3 Sample images of pH Calibration
For further information read chapter 4.
n Wellness reset
Go to Sensor menu> tap . Read 2.3.
n Sensor reset
On Sensor menu, tap . Read 2.4.

<1. Sensor Menu Outline> 1-2
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
n Congure sensor
Converter menu or Sensor menu > “Setting”
Go to Converter menu to congure the setting of converter such as mA output, display setting.
Go to Sensor menu to congure the sensor setting such as calibration setting.
Figure 1.4 Sensor conguration (parameter list)
Select a parameter to change. The parameter becomes highlighted. To overwrite the data, tap
Read Chapter3 about sensor conguration.

<2. Sensor menu> 2-1
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
2 Sensor menu
Main screen > Sensor menu
The following operation are available.
Detail (details on sensors)
Calibration (sensor calibration)
Setting (sensor setting)
etc.
2.1 2.2 2.3
2.52.4
Figure 2.1 Sensor menu (sample)

<2. Sensor menu> 2-2
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
2.1 Detail
Go to Sensor menu > “Detail” to check details (setup, sensor diagnosis, calibration, and
module production number).
In case of trouble, when you contact Yokogawa service, please inform us of the module and
FLXA402 software revision displayed on the Detail and module production number, revision
number indicated on the nameplate attached to the instrument.
*3
*1
*2
Figure 2.2 Sensor menu ow chart
*1: “----”is displayed, depending on a calibration or sensor conguration that a user implements.
*2: The number of log page goes as many as the connected sensors.
*3: ID chip information is displayed only for SENCOM SA. For analog sensor module, internal serial number, for SENCOM SA, serial
number are displayed.

<2. Sensor menu> 2-3
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
n Measurement value
lpH/ORP_Zero(1/2)
Calibrated sensor o󰀨set in mV. Theoretically, the sensor reads 0 mV in a bu󰀨er solution of pH 7.
The ZERO value indicates the condition of the sensor. The trend of ZERO drift of the sensor is
used to predict the lifetime of the sensor.
ZERO can also be displayed in pH units and then it represents the pH value where the sensor
output is 0 mV at 25ºC.
For setting directly go to Sensor menu> “Measure setting”> “Calibration setting”> “Zero/Slope/
ITP”> “Zero”. Read 3.3.1 for the details.
lpH/ORP_Zero(1/2)
Calibrated e󰀩ciency of the sensor unit in percentage of theoretical slope of the sensor unit.
The theoretical slope follows the NERNST equation and is 59.16 mV/pH. The SLOPE can be
calibrated only after a two-point calibration in bu󰀨er solutions with a di󰀨erent pH value. A low
slope indicates that the sensor is not clean or it indicates a bad sensor.
The SLOPE can also be displayed as mV/pH value at 25 ºC
if the user has dened this variable as mV/pH in user setting.
For setting directly go to Sensor menu> “Measure setting”> “Calibration setting”> “Zero/Slope/
ITP”> “Slope”. Read 3.3.1 for the details.
pH14
pH0
pH7, 0mV
+mV
-mV
Theoretical value
Calibration curve (slope)
Zero
Figure 2.3 Zero/Slope
lITP
ITP represents a pH value where the output of the sensor does not change with temperature.For
further information, see ペ3.3.1 Cal. set pHペ
l pH/ORP_Sensor
Represents the electromotive force of the sensor.

<2. Sensor menu> 2-4
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
lImpedance 1
For a PH sensor, “Impedance” shows electrical resistance of the glass membrane electrode. The
FLXA402 checks the impedance to know damage of the electrode.
For an ORP sensor, “Impedance” shows electrical resistance of metal electrode. The FLXA402
checks the impedance to know the surface condition of smudge and the snapping of sensor
wires.
In case of “Input Impedance setting” is “High” and the measured input-1 impedance value is
higher than 100 kΩ, the display shows “MΩ RANGE”. The measured input-1 impedance value is
lower than 100 kΩ, display shows “BAD”. If impedance is set to “Low”, the measured impedance
value is displayed.
If Impedance measurement(A) is set to “Disabled”, “----”is displayed. You can change the setting
of Impedance measurement (A) only when PH sensor module is in use.
To change the setting, go to Sensor menu > Wellness settings > Impedance settings >
Impedance measure (A) See 3.4.1 for the details.
lImpedance 2
Impedance shows the electrical resistance of the reference electrode liquid junction. The liquid
junction forms the electrolytic contact between the reference electrode and the measuring
electrode. Therefore, it must be kept clean and lled with conductive electrolyte. Otherwise the
measurement will su󰀨er from instability, drift and measuring errors.
In case of “Input Impedance setting” is “High” and the measured input-2 impedance value is
higher than 100 kΩ, the display shows “MΩ RANGE”. The measured input-2 impedance value is
lower than 100 kΩ, display shows “BAD”. If Impedance is set to “Low”, the measured impedance
value is displayed.
If Impedance measurement(A) is set to “Disabled”, “----”is displayed. You can change the setting
of Impedance measurement (A) only when PH sensor module is in use. To change the setting, go
to Sensor menu > Wellness settings > Impedance settings > Impedance measure (A). See 3.4.1
for the details.
n Sensor wellness
Sensor wellness shows the soundness of a sensor. The larger number of nappears in each
gauge, the more sound the parameter concerned is. A gauge is indicated for only those
parameters whose sensor wellness setting is “enabled, “while a bar (----) is displayed if the
sensor wellness setting is “disabled.”
When analog sensor module is in use, if Impedance measurement (A) is set to “Disabled”, “----”is
displayed, even if Impedance wellness is “Enabled”.
For Sensor wellness, go to Sensor menu > Congure sensor > Wellness settings
See 3.4 for the details.
When a sensor or an electrode is exchanged or replaced, sensor wellness data should be reset.
Use Reset welness in Sensor menu. See 2.3.

<2. Sensor menu> 2-5
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
n SENCOM Sensor status
The status of the sensor is displayed.
l Max temp. exposed
Displays the maximum temperature, which is automatically updated every time a higher
temperature is measured.
l High pH total time/Low pH total time
Displays the total time during which the pH value remains above the upper pH limit or below the
lower pH limit.
Up to 10 years (87600 hours) can be counted, after which the time is no longer updated.
To set the parameters of High/Low pH value, go to Sensor menu > Congure sensor > Wellness
settings > Dene Sencom status
lSterilization
Displays the number of times the temperature remains above the preset value for at least the
prescribed time period (min.).
Go to Sensor menu > Congure sensor > Wellness settings > Dene SENCOM status
An example of sterilization
User-defined sterilization time
User-defined
sterilization
temperature
Time
(min)
Temperature (°C)
a b c
Figure 2.4 Sterilization
a: does not count, because the length of time that the temperature exceeds the sterilization
temperature is shorter than the length of sterilization time.
b: counts, because the length of time that the temperature exceeds the sterilization
temperature is longer than the length of sterilization time.
c: counts, because the length of time that the temperature exceeds the sterilization
temperature is longer than the length of sterilization time.
If the temperature exceeds the sterilization temperature longer than the length of
sterilization time consecutively, the event counts as one.
The last time when the event counts is displayed as a last sterilization date/time.
Counter indicates a maximum of 9999. After the counter reaches the maximum, if the
requirements to count is satised, the data of last sterilization date and time is updated.
l High temp 1 total, Last date of High temp1, High temp 2 total
To dene the temperature of “High temp 1” and “High temp 2”, go to Sensor menu > Congure
sensor > Wellness settings > Dene Sencom status
The total length of time that the measured temperature exceeds the dened High temp 1 or High
temp 2.
Displays the total time during which the temperature remains over the high temperature 1 or 2.
The last date and time (the end of high-temperature condition) is displayed as the “last date. “Up
to 10 years (87600 hours) can be counted. Even after that, the “last date” is updated if the event
meets the conditions.

<2. Sensor menu> 2-6
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
nPredict. maintenance
l Last calibrated at
Date on which the last sensor calibration was performed. The displayed value of the Zero is the
result of this calibration. The displayed value of Slope was calibrated on this date only if the last
calibration was a 2-point calibration.
lCalibration due at
Date when the calibration must be done next according to the settings of the calibration interval.
To set the calibration intervals, go to Sensor menu > Calibration settings > Limits and timing
>Calib. interval
lProjected maintenance
The projected maintenance function predicts the date when the sensor unit will need recalibrating
for maintaining measurement accuracy. The function checks the input-2 impedance (reference
impedance) every 24 hours.
The function predicts the date when the input-2 impedance will cross the upper or lower limits,
and indicates the date and its status (the status is displayed in parentheses).
As shown in the gure below, the date is predicted based on the intersection point of the upper or
lower limits and the extrapolated line of the values obtained by the least squares method.
Day
Impedance 2
Value
Lower limit
Upper limit
Current
date
Projected
maintenance date
Figure 2.5 Projected maintenance
The status shows the certainty of the projected maintenance date in terms of the correlation
coe󰀩cient R. Table 2.1, Table 2.2 shows pattern of the projected maintenance date, status.
Table 2.1 Display pattern of the projected maintenance date
Projected
date ---- 0-1 month 1-3 months 3-6 months 6-12 months Over 1 year
- - : not predictable due to insu󰀩cient data
Table Display pattern of the status
Status (- - - - -) (Poor) Reasonable) (Excellent)
Criteria (R < 0.50) (0.50 ≤ R < 0.70) (0.70 ≤ R < 0.85) (0.85 ≤ R < 1.00)

<2. Sensor menu> 2-7
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
lProjected replacement
The projected replacement function predicts the date when the sensor will need replacing for
maintaining the measurement accuracy, based on the pH zero and pH slope on each calibration,
and Impedance 2 after each calibration. The projected replacement date is predicted based
on these parameters stored upon calibration, and displayed the same as that of projected
maintenance. For details, see the description about the projected maintenance. Since three
parameters (pH zero, pH slope, and Impedance 2 after calibration) are used for this projection,
the nearest coming day is selected as the projected replacement date from the extrapolated line
of the values obtained by the least squares method.
nPH module
This screen enables operators to check the module Serial No., Hardware Rev, Software Rev.
When SENCOM SA is used, you can check the serial number, Hardware Rev., Software Rev.
ID chip information (Sensor Model code , Serial No.) of the ID chip installed in the sensor.
sensor’s model code and serial number.
n Converter log, Sensor log
Same display as on the converter “Detail”.
See 3.1 in IM 12A01F01-03EN Operation of Converter.

<2. Sensor menu> 2-8
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
2.2 Calibration
Sensor menu > Calibration . See Chapter 4.
Figure 2.6 Calibration selection
If you have a password, a prompt dialog box appears to input your password. After the password
is veried, the page shifts to Calibration.
For password, see 5.4 in IM 12A01F01-03EN Operation of Converter.
2.3 Reset wellness
Sensor menu > Reset wellness
A dialog box appears to ask if you want to reset sensor wellness data.
Yes: the wellness is reset
No: the reset will not take place. The page returns to Sensor menu.
Figure 2.7 Reset wellness and diaglog
If you created a password, a prompt dialog box appears to input your password. After the
password is veried, a dialog appears to conrm if you want to reset.
For password, see 5.4 in IM 12A01F01-03EN Operation of Converter.

<2. Sensor menu> 2-9
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
2.4 Reset
Sensor menu > Reset
The screen jumps to Load PH cong. File screen, where you can reset parameters of analog
sensor module, SENCOM SA.
While Wash is in progress, “Reset”is invalid. Even if you tap the icon, you will not jump to the
sensor reset screen.
Figure 2.8 Reset in sensor menu
In the box of File name, name of dened sensor cong. le to load is displayed, after sensors
connected are automatically detected. You cannot change the le name.
If you tap “Execute”, the loading starts. When the loading ends, you will return to Sensor menu.
If you create a password, a prompt dialog box appears to enter the password. After the password
is veried, Sensor reset screen appears.
For password, see 5.4 in IM 12A01F01-03EN Operation of Converter.
If you go to Sensor reset screen, mA output becomes HOLD, and contact output keeps the
current status.
2.5 Sensor settings
Sensor menu > Setting > Sensor setting
When Wash is in progress, the character row is displayed in color. You cannot move to Sensor
settings.
For further information on sensor settings, read chapter 3.
Figure 2.9 Sensor setting
If you create a password, a prompt dialog box appears to enter the password. After the password
is veried, Sensor setting is displayed.
For password, see 5.4 in IM 12A01F01-03EN Operation of Converter.
If you go to Sensor setting, the mA output becomes HOLD, and contact output keeps the current
status.

<2. Sensor menu> 2-10
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00

<3. Sensor setting> 3-1
IM 12A01F02-01EN 1st Edition : Nov. 22, 2018-00
3. Sensor setting
When you congure each setting, ll in User setting table we provide, and keep it in safe place.
Download the user setting table from our website below.
http://www.yokogawa.com/an/xa402/download/
Congure sensor setting
Go to Main screen > Sensor menu > Sensor setting
You can conrm or edit the setting. When you go to Sensor setting, mA output becomes HOLD,
and contact output keeps the current status.
Figre 3.1 Sensor menu to Sensor setting
To know how to conrm or edit the settings with parameters, refer IM 12A01F01-03EN Operation
of Converter.
In the parameter list of Sensor setting, parameters with (A) or (S) represent (A) for Analog sensor
module, (S) for exclusively SENCOM SA.
You cannot congure parameters which do not apply to the sensors to be used.
NOTE
As for some parameters, you don’t need to congure parameter, because when SENCOM SA is
connected, the data stored in ID chip is read automatically. Even when you edit some parameter
setting, if you insert/remove sensors or power on/o󰀨 SENCOM SA, the original data stored in ID
chip installed in the sensor is read automatically and the originally stored parameter will not be
overwritten.
We recommend that you should not change setting when SENCOM SA is connected.
When you congure sensor setting and save the data, a dialog box appears to notify the
operation is in progress. If you succeed the conguration, you will return to parameter list, and if
fail, a fail dialog appears.
NOTE
When setting parameters, FLXA402 features parameter reviewing function, which secures the
parameter accuracy by network communication.
You might nd the end of a value you set edited. This does not a󰀨ect any measurement or
arithmetic.