YOKOGAWA PH202G User Manual

User’s
Manual

Model PH202G (S)
pH Transmitter

IM 12B6C3-E-E

12th Edition

Y

OKOGAWA

IM 12B6C3-E-E

TABLE OF CONTENTS

PREFACE

1. INTRODUCTION AND GENERAL DESCRIPTION ..................................................................... 1-1

1-1. Instrument check ...................................................................................................................

1-1

1-2. Application ............................................................................................................................... 1-2

2. PH202 SPECIFICATIONS ............................................................................................................. 2-1

2-1. Genera• ................................................................................................................................... 2-1

2-2. Operating specifications ........................................................................................................... 2-2

2-3. Model and suffix codes ............................................................................................................ 2-3

2-4. Intrinsic safety - common specifications ................................................................................... 2-4

2-5. Connection diagrams for power supply .................................................................................... 2-5

3. INSTALLATION AND WIRING ......................................................................................................

3-1

3-1. Installation and dimensions ...................................................................................................... 3-1

3-1-1. Installation site ............................................................................................................ 3-1

3-1-2. Mounting methods ...................................................................................................... 3-1

3-2. Preparation .............................................................................................................................. 3-3

3-2-1. Cables, terminals and glands ...................................................................................... 3-3

3-3. Wiring of sensors ..................................................................................................................... 3-4

3-3-1. General precautions .................................................................................................... 3-4

3-3-2. Additional precautions for installations in hazardous areas .......................................... 3-4

3-3-3. Hazardous area non-incendive PH 202S-N ................................................................ 3-4

3-3-4. Liquid earth ................................................................................................................. 3-5

3-3-5. Access to terminal and cable entry ............................................................................. 3-5

3-4. Wiring of power supply ............................................................................................................ 3-5

3-4-1. General precautions .................................................................................................... 3-5

3-4-2. Connection of the power supply ................................................................................. 3-5

3-4-3. Switching the instrument on ........................................................................................ 3-6

3-5. Wiring the sensor system ......................................................................................................... 3-7

3-5-1. Impedance measurement jumper settings .................................................................. 3-7

3-6. Sensor wiring ........................................................................................................................... 3-8

3-6-1. Connection cable ........................................................................................................ 3-9

3-6-2. Sensor cable connection with special grommet ........................................................ 3-10

3-6-3. Sensor cable connections using junction box (BA10) and extension cable (WF10) ... 3-11

4. OPERATION; DISPLAY FUNCTIONS AND SETTING .................................................................

4-1

4-1. Operator interface .................................................................................................................... 4-1

4-2. Explanation of operating keys .................................................................................................. 4-2

4-3. Setting passcodes ................................................................................................................... 4-3

4-3-1. Passcode protection ................................................................................................... 4-3

4-4. Display examples .................................................................................................................... 4-3

4-5. Display functions .................................................................................................................... 4-4

4-5-1. Display functions pH (default) ...................................................................................... 4-4

4-5-2. Display functions pH (ORP) ......................................................................................... 4-5

4-5-3. Display functions pH (rH) ............................................................................................. 4-6

5. PARAMETER SETTING ................................................................................................................

5-1

5-1. Maintenance mode .................................................................................................................. 5-1

5-1-1. Manual temperature selection and adjustment ............................................................ 5-2

5-1-2. Process temperature measuring in ORP mode ........................................................... 5-3

5-1-3. Manual activation of HOLD .............................................................................................. 5-4

5-1-4. Manual impedance check ................................................................................................ 5-5

IM 12B6C3-E-E

5-2. Commissioning mode ................................................................................................................... 5-6

5-2-1. Output Range .................................................................................................................. 5-7

5-2-2. Hold ................................................................................................................................ 5-8

5-2-3. Service .......................................................................................................................... 5-10

5-3. Notes for guidance in the use of service coded settings ............................................................. 5-11

5-3-1. Parameter specific functions .......................................................................................... 5-12

5-3-2. Temperature compensation and measuring functions ................................................... 5-14

5-3-3. Calibration functions ...................................................................................................... 5-16

5-3-4. mA Output functions ..................................................................................................... 5-18

5-3-5. User interface ................................................................................................................ 5-20

5-3-6. Communication setup ................................................................................................... 5-22

5-3-7. Genera• ........................................................................................................................ 5-22

5-3-8. Test and setup mode .................................................................................................... 5-22

6. CALIBRATION ................................................................................................................................

6-1

6-1. Automatic calibration ............................................................................................................... 6-1

6-2. Manual calibration .................................................................................................................... 6-1

6-3. Sample calibration ................................................................................................................... 6-1

6-4. Data entry ................................................................................................................................ 6-1

6-5. Calibration procedures ............................................................................................................. 6-2

6-5-1. Automatic calibration .................................................................................................. 6-2

6-5-2. Automatic calibration with HOLD active ...................................................................... 6-3

6-5-3. Manual calibration (2nd parameter calibration) ............................................................ 6-4

6-5-4. Sample calibration ...................................................................................................... 6-6

7. MAINTENANCE ..............................................................................................................................

7-1

7-1. Periodic maintenance for the EXA transmitter .......................................................................... 7-1

7-2. Periodic maintenance for the sensor system ............................................................................ 7-1

8. TROUBLESHOOTING ....................................................................................................................

8-1

8-1. Diagnostics .............................................................................................................................. 8-2

8-1-1. Off-line calibration checks ........................................................................................... 8-2

8-1-2. On-line impedance checks ......................................................................................... 8-2

8-1-3. Error Codes ................................................................................................................ 8-3

9. SPARE PARTS ...............................................................................................................................

9-1

10. APPENDIX ..................................................................................................................................

10-1

10-1. User setting table ................................................................................................................. 10-1

10-2. Configuration checklist for PH202G ..................................................................................... 10-3

10-3. Set up for sensor compatibility ............................................................................................. 10-4

10-3-1. Genera• .................................................................................................................. 10-4

10-3-2. Selection of measurement and reference electrode ................................................ 10-4

10-3-3. Selecting a temperature sensor .............................................................................. 10-4

10-4. Set up for other functions .................................................................................................... 10-5

10-5. Set up for Pfaudler Type 18 sensor ..................................................................................... 10-6

10-5-1. General set up ........................................................................................................ 10-6

10-5-2. Calibration set up .................................................................................................... 10-6

10-6. Device Description (DD) menu structure ............................................................................... 10-7

10-7. Field Change Order .............................................................................................................. 10-8

11. TEST CERTIFICATE ...................................................................................................................

10-1

In this manual a

mA

sign appears if it concerns the pH202G(S)-E/C/U/N

IM 12B6C3-E-E

PREFACE

Electric discharge

The EXA analyzer contains devices that can be damaged by electrostatic discharge. When servicing
this equipment, please observe proper procedures to prevent such damage. Replacement components
should be shipped in conductive packaging. Repair work should be done at grounded workstations using
grounded soldering irons and wrist straps to avoid electrostatic discharge.

Installation and wiring

The EXA analyzer should only be used with equipment that meets the relevant IEC, American or Canadian
standards. Yokogawa accepts no responsibility for the misuse of this unit.

The Instrument is packed carefully with shock absorbing materials, nevertheless, the instrument may be
damaged or broken if subjected to strong shock, such as if the instrument is dropped. Handle with care.

Although the instrument has a weatherproof construction, the transmitter can be harmed if it becomes
submerged in water or becomes excessively wet.

Do not use an abrasive or solvent in cleaning the instrument.

Notice

Contents of this manual are subject to change without notice. Yokogawa is not responsible for damage
to the instrument, poor performance of the instrument or losses resulting from such, if the problems are
caused by:

• Improper operation by the user.

• Use of the instrument in improper applications

• Use of the instrument in an improper environment or improper utility program

• Repair or modification of the related instrument by an engineer not authorized by Yokogawa.

Warranty and service

Yokogawa products and parts are guaranteed free from defects in workmanship and material under normal
use and service for a period of (typically) 12 months from the date of shipment from the manufacturer.
Individual sales organizations can deviate from the typical warranty period, and the conditions of sale
relating to the original purchase order should be consulted. Damage caused by wear and tear, inadequate
maintenance, corrosion, or by the effects of chemical processes are excluded from this warranty coverage.

In the event of warranty claim, the defective goods should be sent (freight paid) to the service department of
the relevant sales organization for repair or replacement (at Yokogawa discretion). The following information
must be included in the letter accompanying the returned goods:

• Part number, model code and serial number

• Original purchase order and date

• Length of time in service and a description of the process

• Description of the fault, and the circumstances of failure

• Process/environmental conditions that may be related to the installation failure of the device

• A statement whether warranty or non-warranty service is requested

• Complete shipping and billing instructions for return of material, plus the name and phone number of a

contact person who can be reached for further information.

Returned goods that have been in contact with process fluids must be decontaminated/disinfected before
shipment. Goods should carry a certificate to this effect, for the health and safety of our employees. Material
safety data sheets should also be included for all components of the processes to which the equipment has
been exposed.

WARNING

CAUTION

Introduction 1-1

IM 12B6C3-E-E

1. INTRODUCTION AND GENERAL DESCRIPTION

The Yokogawa EXA 202 is a 2-wire transmitter designed for industrial process monitoring, measurement
and control applications. This user’s manual contains the information needed to install, set up, operate and
maintain the unit correctly. This manual also includes a basic troubleshooting guide to answer typical user
questions.

Yokogawa can not be responsible for the performance of the EXA analyzer if these instructions are not
followed.

1-1. Instrument check

Upon delivery, unpack the
instrument carefully and inspect it
to ensure that it was not damaged
during shipment. If damage is
found, retain the original packing
materials (including the outer box)
and then immediately notify the
carrier and the relevant Yokogawa
sales office.

Make sure the model number on
the textplate affixed to the side of
the instrument agrees with your
order. Examples of nameplates are
shown.

Figure 1-1. Nameplate

N200

pH / ORP TRANSMITTER

PROFIBUS - PA

-10 TO 55 ºC

SUPPLY

OUTPUT

AMB.TEMP. [Ta]

SERIAL No.

EEx ib [ia] IIC T4 for Ta -10 to 55 ºC
EEx ib [ia] IIC T6 for Ta -10 to 40 ºC
KEMA 00ATEX1068 X

IS CL I, DIV 1, GP ABCD
T3B for Ta -10 to 55 ºC

T4 for Ta -10 to 40 ºC

MODEL

EXA PH202S

0344

II 2 (1) G

24VDC/250mA/1,2W

FISCO 17,5VDC/380mA/5,32W

Li=2,6µH Ci=737pF

or

HAZ LOC per Control Drawing
FF1-PH202S-00

Amersfoort,
The Netherlands

PH202S CSA

WARNING

Substitution of
components may impair
intrinsic safety

AVERTISSEMENT

La substitution de composants
peut compromettre la sècurite
intrinsëque.

Refer to Installation Drawing

T4 for Ta -10 to 55 ºC
T6 for Ta -10 to 40 ºC

Ex ia CL I, DIV 1, GP ABCD,

IM 12B6C3-E-E

1-2 Introduction

NOTE: The nameplate will also contain the serial number and any relevant

certification marks. Be sure to apply correct power to the unit.
The first two characters of the serial number refers to the year
and month of manufacturing

Check that all the parts are present, including mounting hardware,
as specified in the option codes at the end of the model number.
For a description of the model codes, refer to Chapter 2 of this
manual under General Specifications.

Basic Parts List: Transmitter PH202
User’s Manual (See model code for language)
Optional mounting hardware when specified (See model code)

NOTE: mounting screws and special grommet are packed in the terminal compartment,

together with a second link for impedance selection.

1-2. Application

The EXA converter is intended to be used for continuous on-line measurement in industrial installations. The
unit combines simple operation and microprocessor-based performance with advanced self-diagnostics
and enhanced communications capability to meet the most advanced requirements. The measurement can
be used as part of an automated process control system. It can also be used to indicate dangerous limits
of a process, to monitor product quality, or to function as a simple controller for a dosing/neutralization
system.

Yokogawa designed the EXA analyzer to withstand harsh environments. The converter may be installed
either indoors or outside because the IP65 (NEMA4X) housing and cabling glands ensure the unit is
adequately protected. The flexible polycarbonate window on the front door of the EXA allows pushbutton
access to the keypad, thus preserving the water and dust protection of the unit even during routine
maintenance operations.
A variety of EXA hardware is optionally available to allow wall, pipe, or panel mounting. Selecting a proper
installation site will permit ease of operation. Sensors should normally be mounted close to the converter
in order to ensure easy calibration and peak performance. If the unit must be mounted remotely from the
sensors, WF10 extension cable can be used up to a maximum of 50 metres (150 feet) with a BA10 junction
box. Except installations with dual high impedance sensors, where the maximum cable length is 20 metres
using integral cable only (no junction box).

The EXA is delivered with a general purpose default setting for programmable items. (Default settings are
listed in Chapter 5 and again in Chapter 10). While this initial configuration allows easy start-up, the
configuration should be adjusted to suit each particular application. An example of an adjustable item
is the type of temperature sensor used. The EXA can be adjusted for any one of eight different types of
temperature sensors.

To record such configuration adjustments, write changes in the space provided in Chapter 10 of this
manual. Because the EXA is suitable for use as a monitor, a controller or an alarm instrument, program
configuration possibilities are numerous.

Details provided in this user’s manual are sufficient to operate the EXA with all Yokogawa sensor
systems and a wide range of third-party commercially available probes. For best results, read this manual
in conjunction with the corresponding sensor user’s manual.

Yokogawa designed and built the EXA to meet the CE regulatory standards. The unit meets or exceeds
stringent requirements of EN 55082-2, EN55022 Class A without compromise, to assure the user of
continued accurate performance in even the most demanding industrial installations.

Y = Year M = Month

2000 M January 1
2001 N February 2
2002 P March 3
2003 R Apri• 4

........ .. .......... ..

2008 W September 9
2009 X October O
2010 A November N
2011 B December D

IM 12B6C3-E-E

2-1. General
A. Input specifications
: Dual high impedance inputs

(2 x 1013) with provision
for liquid earth connection.
Suitable for inputs from glass
or enamel pH & reference
sensors and ORP metal
electrodes.

B. Input ranges

- pH : -2 to 16 pH

- ORP : -1500 to 1500 mV

- rH : 0 to 55 rH

- Temperature : -30 ºC - 140 ºC (-20 - 300 ºF)

- 8k55 sensor : -10 ºC - 120 ºC (10 - 250 ºF)

- PTC10k : -20 ºC - 140 ºC (0 - 300 ºF)

C. Span

- pH : min 1 max 20 pH

- ORP : min 100 max 3000 mV

- rH : min 2 max 55 rH

D. Output signa• : 4-20 mA loop powered,

isolated from input,
maximum load 425  at 24 V
DC. With the possibility of
22 mA “FAIL” signal (burn up)
and 3.9 mA (burn down).

E. Temperature compensation

- Range : Automatic or manual
compensation to Nernst
equation.
Process compensation by
configurable coefficient.
Compensation for total range
of selected temperature
sensors (see B)
Adjustable ITP (Iso-thermal
point of intersection).

F. Calibration : Semi-automatic using pre-

configured NIST buffer tables
4, 7 & 9, of with user defined
buffer tables, with automatic
stability check.
Manual adjustment to grab
sample.
Slope and Asymmetry
Potential setting.
Zero point can be selected for
calibration and display instead
or As. Pot. (IEC746-2)

G. Serial communication

: Bi-directional HART® digital

communication superimposed
on the 4-20 mA signal.

H. Logbook : Software record of important

events and diagnostic data.
Available through HART
link, with key diagnostic
information available in the
display.

I. Display : Custom liquid crystal display,

with a main display of 31/2
digits 12.5 mm high.
Message display of 6
alphanumeric characters, 7
mm high.
Warning flags and units (pH
and mV).

J. Power supply : Nominal 24 volt DC loop

powered system.

- PH202G : Up to 40 volts.

- PH202S : Up to 31.5 volts.

NOTE: The transmitter contains a switched power

supply. The transmitter requires a minimum
Power voltage in order to work correctly, which
is dependant on the load. Please refer to figures
2-1 and 2-2 for the correct power supply.

2. PH202 SPECIFICATIONS

Fig. 2-1. Supply voltage/ load diagram

Fig. 2-2. Minimum terminal voltage at the PH202

0.0

20

0.0

40

0.0

60

0.0

80

0.0

1000.0

1200.0

12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

4 mA

22 mA

425.0

775.0

31.5 V

(limit for IS version)

Voltage (V)

Load Resistance (Ω)

230.0

1100.0

Communication

Range

17 Volts

14.5 Volts

4 mA 7 mA 20 mA

Te

rminal voltage (V)

Output Current (mA)

mA

mA

Specification 2-1

mA

IM 12B6C3-E-E

2-2 Specification

K. Input isolation : 1000V DC

2-2. Operating specifications
A. Performance : pH

- Linearity :

0.01 pH ± 0.02 mA

- Repeatability : <0.01 pH ± 0.02 mA

- Accuracy : 0.01 pH ± 0.02 mA

Performance : ORP

- Linearity : 1 mV ± 0.02 mA

- Repeatability : <1 mV ± 0.02 mA

- Accuracy : 1 mV ± 0.02 mA
Performance :

Temperature with Pt1000 ,

3U Balco, 5k U, 35 U, 6k U ,

PTC10k & 8k55

- Linearity : 0.3 ˚C ± 0.02 mA

- Repeatability : <0.1 ˚C ± 0.02 mA

- Accuracy : 0.3 ˚C ± 0.02 mA

Performance : Temperature with Pt100 

- Linearity : 0.4 ˚C ± 0.02 mA

- Repeatability : <0.1 ˚C ± 0.02 mA

- Accuracy : 0.4 ˚C ± 0.02 mA

B. Ambient operating temperature

: -10 to + 55 ˚C (10 to 131 ˚F)

Excursions to -30˚C (-20
˚F) do not influence the
current output function, and
excursions to + 70˚C (160˚F)
are acceptable too.

C. Storage temperature
: -30 to +70 ˚C (-20 to 160 ˚F)

D. Humidity : 10 to 90% RH

E. HART specification

- Min. cable diameter : 0.51 mm, 24 AWG

- Max. cable length : 1500 m

- Detailed information can be found at:
www.hartcomm.org

F. Housing : Cast aluminium case

with chemically resistant
coating, cover with flexible
polycarbonate window. Case
color is off-white and cover
is moss green. Cable entry is
via two

1

/2” polyamide glands.
Cable terminals are provided
for up to 2.5 mm2 finished
wires. Weather resistant to
IP65 and NEMA 4X standards.
Pipe wall or panel mounting,
using optional hardware.

G. Shipping details : Package size w x h x d

290 x 225 x 170 mm.

11.5 x 8.9 x 6.7 in.
Packed weight approximately

2.5 kg (5lb).

H. Data protection : EEPROM for configuration and

logbook, and lithium cell for
clock.

I. Watchdog timer : Checks microprocessor

J. Automatic safeguard
: Return to measuring mode

when no keystroke is made
for 10 min.

K. Operation protection

: 3-digit programmable

password.

L. Sensor impedance checking

: Independent impedance

check on measuring
and reference sensor
elements, with temperature
compensation. Display
of sensor impedance on
message line of display. FAIL
flag in event of “out of limits”
impedance, and the possibility
of 22 mA or 3.9 mA error
signal.

M. DD Specification

: The PH202 Device
Description is available ena­ bling communications with
the Handheld communicator

(HHC) and compatible
devices. For more information
contact your local Yokogawa
sales offices.

mA

IM 12B6C3-E-E

Mode• Suffix Code Option code Description

PH202G PH/ORP Transmitter, General Purpose version
Type - E Milli-amp (+HART) version, European style

- C Milli-amp (+HART) version, Canadian style

- U Milli-amp (+HART) version, North American style

- F FOUNDATION ® Fieldbus version

- P Profibus PA version

- E Always E
Options /H Hood for Sun Protection
/U Pipe & Wall mounting hardware
/SCT Stainless steel tagplate
/Q Calibration certificate

Mode• Suffix Code Option code Description

PH202S PH/ORP Transmitter, Intrinsic Safe version
Type - E Milli-amp (+HART) version, European style

- C Milli-amp (+HART) version, Canadian style

- U Milli-amp (+HART) version, North American style

- F FOUNDATION ® Fieldbus version

- P Profibus PA version

- N Non-Incendive Milli-amp (+HART) version

- B Non-Incendive FOUNDATION ® Fieldbus version

- D Non-Incendive Profibus PA version

- E Always E
Options /H Hood for Sun Protection
/U Pipe & Wall mounting hardware
/SCT Stainless steel tagplate
/Q Calibration certificate

2-3. Model and suffix codes

N. Regulatory compliance

- EMC : meets council directive 89/336/EEC

- Emmission : meets EN 55022 Class A

- Immunity : meets EN 61000-6-2

O. Intrinsic safety

- ATEX

: EEx ib [ia] IIC T4 for Ta -10 to 55 ºC

EEx ib [ia] IIC T6 for Ta -10 to 40 ºC

II 2 (1) G

KEMA 00ATEX1068 X

- CSA : Ex ia CL 1, DIV 1, GP C&D,
T3C for Ta -10 to 55 ºC
Refer to Installation Drawing
PH202S CSA

- FM : IS CL 1, DIV 1, GP ABCD
T3B for Ta -10 to 55 ºC
T4 for Ta -10 to 40 ºC
HAZ LOC per Control Drawing
FF1-PH202S-00

P. Non-Incendive

- FM : NI CL 1, DIV 2, GP ABCD

T3B for Ta -10 to 55 ºC
T4 for Ta -10 to 40 ºC
HAZ LOC per Control Drawing
FF1-PH202S-00

- ATEX : EEx nA [L] IIC T4 for Ta -10 to 55 ºC
EEx nA [L] IIC T6 for Ta -10 to 40 ºC

II 3 G

KEMA 00ATEX1115 X

Specification 2-3

IM 12B6C3-E-E

2-4 Specification

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S

Title : Control Drawing PH202S Cenelec

Number : FF1-PH202S-00 Page : 1 of 10

Revision : 5.4

EXA PH202S

(pH/ORP-transmitter)

Safe area

Uo = 31.5 Volt DC

Io = 100 mA

Po = 1.2 Watt

EEX ib Certified Repeater

Power Supply

(HART Compatible)

Output

Supply

SENSOR(S)

terminals 11-19

+_G

SENSOR(S)

terminals 11-19

Zone 0 or 1 Zone 1

Hazardous area

Safe area

+_G

Protective

earth

Protective

earth

Intrinsically safe design

CENELEC standard EEX ib [ia] IIC: T4 for ambient temp. < 55¡C

T6 for ambient temp. < 40¡C

Certificate nr. 00ATEX1068 X

EXA PH202S

+

_

Load

Resistance

EEX ib

Certified safety barrier or power

with Rint=300

Ω

Io = 100 mA

Uo = 31.5 Volt DC

Zone 0 or 1

Zone 1

Hazardous area

Protective

earth

+

_

24 volts DC Nominal

Supply Voltage.

Intrinsically safe design

CENELEC standard EEX ib [ia] IIC: T4 for ambient temp. < 55¡C

T6 for ambient temp.< 40¡C

Certificate nr. 00ATEX1068 X

(HART compatible)

(pH/ORP-transmitter)

• Sensor(s) are of a passive type to be regarded as simple apparatus , devices which comply with clause 1.3 of the

EN 50014.

• Electrical data of the EXAPH202S.

- Supply and output circuit (terminals + and -):

Maximum input voltage U

i

= 31.5 V.

Maximum input current I

i

= 100 mA.

Maximum input power P

i

= 1.2 W.

Effective internal capacitance C

i

= 22 nF.

Effective internal inductance L

i

= 22 µH.

- Sensor input circuit (terminals 11 through 19):

Maximum output voltage U

o

= 14.4 V.

Maximum output current I

o

= 32.3 mA.

Maximum allowed external capacitance C

o

= 600 nF.

Maximum allowed external inductance L

o

= 36 mH.

• Barriers and power supply specification must not exceed the maximum values as shown in the diagram above.

These safety descriptions cover most of the commonly used industry standard barriers, isolators and power

supplies.

• The Hand Held Communicator must be of a ATEX certified intrinsically safe type in case it is used on the

intrinsically safe circuit in the hazardous area or of a ATEX certified non-incendive type in case it is used in the

non-incendive circuit in the hazardous area.

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

IM 12B6C3-E-E

Specification 2-5

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S

Title : Control Drawing PH202S Cenelec

Number : FF1-PH202S-00 Page : 2 of 10

Revision : 5.4

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

〈 Sensor(s) are of a passive type to be regarded as ’simple apparatus’, devices which

comply with clause 1.3 of the EN 50014.

〈 Electrical data of the EXA PH202S-F & PH202S-P:

- Supply and output circuit::

Maximum input voltage Ui=24 V or Maximum input voltage Ui=17.5 V

Maximum input current Ii=250 mA Maximum input current Ii=380 mA

Maximum input power Pi=1.2 W Maximum input power Pi=5.32 W

Effective internal capacitance Ci=737 pF; Effective internal i nductance Li=2.6

µH.

- Sensor input circuit:

Maximum output voltage Uo=14.4V; Maximum output current Io=32.3 mA

Maximum allowed external capacitance Co=600 nF

Maximum allowed external inductance Lo=36 mH

〈 Any I.S. interface may be used that meets the followi ng requirements:

Uo

≤ 24 V or Uo ≤ 17.5 V

Io

≤ 250 mA Io ≤ 380mA

Po ≤ 1.2 W Po ≤ 5.32 W

Ca

? 737 pF + Ccable; La ? 2.6 µH + Lcable

Safe area

Hazardous area

Zone 1

Zone 0 or 1

Safe area

Apparatus

I.S.

interface

I.S.

certified

Terminator

Sensor

Connections

Ui

=

24 V or Ui

=

17,5 V

Ii

=

250 mA Ii

=

380 mA

Pi

= 1,2 W Pi

=

5,32 W

EEx ib [ia] IIC Certificate no. 00ATEX1068 X

T4 for ambient temp.

≤ 55 ϒC

T6 for ambient tem

p

. ≤ 40 ϒC

EXA

PH202S-F

& PH202S-P

IM 12B6C3-E-E

2-6 Specification

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S

Title : Installation Drawing PH202S CSA

Number : FF1-PH202S-00 Page : 3 of 10

Revision : 5.4

Safe area

Vmax = 31.5 VoltDC

Imax = 100 mA

Pmax = 1.2 Watt

CSA certified

Power Supply

(HART compatible) )

Output

Supply

SENSOR(S)

terminals 11-19

+_G

SENSOR(S)

terminals 11-19

Hazardous area

Safe area

+_G

Protective

earth

Protective

earth

Intrinsically safe design

(pH/ORP-transmitter)

EXA PH202S

+

_

Load

Resistance

Imax = 100 mA

Vmax = 31.5 VoltDC

Hazardous area

Protective

earth

+

_

24 volts DC Nominal

Supply Voltage.

Intrinsically safe design

CSA Ex ia Class1, Div.1, Group C&D, T3C for ambient temp. < 55¡C

(pH/ORP-transmitter)

EXA PH202S

CSA certified

safety barrier or power supply

Suitable values are:

(HART compatible)

CSA Ex ia Class1, Div.1, Group C&D, T3C for ambient temp. < 55¡C

For electrical data:

see text below.

For electrical data:

see text below.

Suitable values are:

• Sensor(s) are thermocouples, RTD s, passive resistive switch devices, or are CSA entity approved and meet

connection requirements.

• Electrical data of the EXA PH202S.

- Supply and output circuit (terminals + and -):

Maximum input voltage V

max

= 31.5 V.

Maximum input current I

max

= 100 mA.

Effective internal capacitance C

i

= 22 nF.

Effective internal inductance L

i

= 22 µH.

- Sensor input circuit (terminals 11 through 19):

Maximum output voltage V

oc

= 14.4 V.

Maximum output current I

sc

= 32.3 mA.

Maximum allowed external capacitance Ca = 600 nF.

Maximum allowed external inductance La = 36 mH.

• Barriers and power supply should be CSA certified. The specifications must not exceed the maximum values as

shown in the diagram above.

Installation should be in accordance with Canadian Electrical Code, Part I or CEC, Part I.

Maximum safe area voltage should not exceed 250 V

RMS

.

• The Hand Held Communicator must be of a CSA certified intrinsically safe type in case it is used on the

intrinsically safe circuit in the hazardous area.

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

IM 12B6C3-E-E

Specification 2-7

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S

Title : Installation Drawing PH202S CSA

Number : FF1-PH202S-00 Page : 4 of 10

Revision : 5.4

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

〈 Sensor(s) are a thermocouple, RTD’s, passive resistive switch devices, or is CSA entity

approved and meet connection requirements.

〈 Electrical data of the EXA PH202S-F & PH202S-P:

- Supply and output circuit::

Maximum input voltage Vmax=24 V or Maximum input voltage Vmax=17.5 V

Maximum input current Imax=250 mA Maximum input current Imax=380 mA

Maximum input power Pmax=1.2 W Maximum input power Pmax=5.32 W

Effective internal capacitance Ci=737 pF; Ef fective internal inductance Li=2.6

µH.

- Sensor input circuit:

Maximum output voltage Voc=14.4V; Maximum output current Isc=32.3 mA

Maximum allowed external capacitance Ca=600 nF

Maximum allowed external inductance La=36 mH

〈 Any CSA approved I.S. interface m ay be used that meets the following requirements:

Vmax

≤ 24 V or Vmax ≤ 17.5 V

Imax

≤ 250 mA Imax ≤ 380mA

Pmax

≤ 1.2 W Pmax ≤ 5.32 W

Ca

? 737 pF + Ccable; La ? 2.6 µH + Lcable

Installation should be in accordance with Canadian Electrical Code, Part I or CEC, Part I.

Maximum safe area voltage should not exceed 250 Vrms.

Safe area

Hazardous area

Zone 1

Zone 0 or 1

Safe area

Apparatus

I.S.

interface

I.S.

certified

Terminator

EXA

PH202S-F

& PH202S-P

Sensor

Connections

V

m

ax

= 24 V or V

max

= 17,5 V

I

max

= 250 mA I

max

= 380 mA

P

m

ax

= 1,2 W P

max

= 5,32 W

CSA Ex ia Class I, DIV. 1, Group C&D

T3C for ambient temp.

≤ 55 ϒC

IM 12B6C3-E-E

2-8 Specification

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S

No revision to drawing without prior

FM Approval

Title : FM Control Drawing PH202S (Intrinsic Safety)

Number : FF1-PH202S-00 Page : 5 of 10

Revision : 5.4

Sensor(s)

terminals 11-19

Max. cablelength: 60 mtr.

Cable dia. : 3 12 mm.

Sensor(s)

terminals 11-19

Max. cablelength: 60 mtr.

Cable dia.: 3 12 mm.

n classified Location

FM Approved

Power Supply

(HART compatible)

Output

Supply

+_G

Classified Location

Unclassified Location

+_G

Protective

earth

Protective

earth

Intrinsically safe design

FM Class I, Div.1, Group ABCD, T3B for ambient temp. < 55¡C

T4 for ambient temp. < 40¡C

EXA PH202S analyser

+

-

Load

Resistance

Classified Location

Protective

earth

+

_

24 volts DC Nominal

Supply Voltage.

FM Approved safety barrier or

power supply

with Rint = 300

Ω

(HART compatible)

For electrical data:

see text below.

For electrical data:

see text below.

Intrinsically safe design

FM Class I, Div.1, Group ABCD, T3B for ambient temp. < 55¡C

T4 for ambient temp. < 40¡C

EXA PH202S analyser

Figure 1

Figure 2

• Electrical data of the EXA PH202S :

- Supply circuit (terminals + and -): - Sensor input circuit (terminals 11 through 19):

Maximum input voltage V

max

= 31.5 V. Maximum output voltage V

t

= 14.4 V.

Maximum input current I

max

= 100 mA. Maximum output current I

t

= 32.3 mA.

Maximum input power P

i

= 1.2 W. Maximum allowed external capacitance C

a

= 600 nF.

Effective internal capacitance C

i

= 22 nF. Maximum allowed external inductance L

a

= 36 mH.

Effective internal inductance L

i

= 22 µH.

• If Hand Held Terminal (HHT) is not connected to the power supply lines of the EXA PH202S (see figure 1):

Any FM Approved barrier or power supply may be used that meets the following requirements.

V

oc

or V

t

≤ 31.5 V; I

sc

or I

t

≤ 100 mA; C

a

≥ 22nF + C

cable

; L

a

≥ 22µH + L

cable

If HHT is connected to the power supply lines of the EXA PH202S (see figure 2):

The Hand Held Terminal must be FM Approved. Refer to the manufacturers control drawing of the HHT and the barrier/power

supply to determine the cable parameters.

(V

oc

or V

t

) + V

HHT

≤ 31.5 V; (I

sc

or I

t

) + I

HHT

≤ 100 mA; C

a

≥ 22nF + C

cable

+ C

HHT

; L

a

≥ 22µH + L

cable

+ L

HHT

When installing this equipment, follow the manufacturer s installation drawing.

Installation should be in accordance with ANSI/ISA RP 12.06.01 Installation of Intrinsically Safe Systems for Hazardous

(Classified) Locations and the National Electrical Code (ANSI/NFPA 70).

Control equipment connected to the barrier/power supply must not use or generate more than 250 Vrms

or Vdc.

• Resistance between Intrinsically Safe Ground and earth ground must be less than 1.0 Ohm.

WARNING

- Substitution of components may impair Intrinsic Safety

- To prevent ignition of flammable or combustible atmospheres, disconnect power before servicing or read, understand

and adhere to the manufacturer s live maintenance procedures.

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

IM 12B6C3-E-E

Specification 2-9

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S-N

No revision to drawing without prior

FM Approval

Title : FM Control Drawing PH202S-N (Non-incendive)

Number : FF1-PH202S-00 Page : 6 of 10

Revision : 5.4

Sensor(s)

terminals 11-19

Max. cablelength: 60 mtr.

Cable dia. : 31 2 mm.

Sensor(s)

terminals 11-19

Max. cablelength: 60 mtr.

Cable dia.: 3 12 mm

n classified Location

+_G

Classified Location

Unclassified Location

+_G

Protective

earth

Intrinsically safe design

FM Class I, Div.2, Group ABCD, T3B for ambient temp. < 55¡C

T4 for ambient temp. < 40¡C

EXA PH202S analyser

+

-

Load

Resistance

Classified Location

Protective

earth

FM Approved

power supply

Voc

¡Ü 31.5 VDC

For electrical data:

see text below.

For electrical data:

see text below.

Intrinsically safe design

FM Class I, Div.2, Group ABCD, T3B for ambient temp. < 55¡C

T4 for ambient temp. < 40¡C

EXA PH202S analyser

+

-

FM Approved

power supply

Voc

¡Ü 31.5 VDC

• Electrical data of the EXA PH202S :

- Supply circuit (terminals + and -): - Sensor input circuit (terminals 11 through 19):

Maximum input voltage V

max

= 31.5 V. Maximum output voltage V

t

= 14.4 V.

Maximum input power Pi = 1.2 W Maximum output current I

t

= 32.3 mA.

Effective internal capacitance Ci = 22 nF Maximum allowed external capacitance C

a

= 600 nF.

Effective internal inductance Li = 22 H Maximum allowed external inductance L

a

= 36 mH.

• The Hand Held Terminal must be FM Approved in case it is used in the classified location.

When installing this equipment, follow the manufacturers installation drawing. Installation shall be in accordance with Article

501.4(B) of the National Electrical Code (ANSI/NFPA 79).

Nonincendive field wiring may be installed in accordance with Article 501.4(B)(3)

• Grounding shall be in accordance with Article 250 of the National Electrical code

WARNING

- Substitution of components may impair suitability for Division 2

- Do not remove or replace while circuit is live unless area is know to be non-hazardous

- Explosion Hazard — Do not disconnect equipment unless area is know to be non-hazardous

- Do not reset circuit breaker unless power has been removed from the equipment or the area is know to be non-

hazardous

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

IM 12B6C3-E-E

2-10 Specification

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S-F & PH202S-P

No revision to drawing without prior

FM Approval

Title : FM Control Drawing PH202S-F & PH202S-P (Intrinsic safe Fisco

concept)

Number : FF1-PH202S-00 Page : 7 of 10

Revision : 5.4

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

〈 Sensor(s) are of a passive type to be regarded as ’simple apparatus’, devices which neither store nor

generate voltages over 1.5 V, currents over 0.1 A, power over 25 mW or energy over 20

µJ, or are FM

Approvals entity approved and meet connection requirements.

〈 Electrical data of the EXA PH202S-F & PH202S-P:

- Supply circuit: Vmax=17,5 V; Imax=380 mA; Pi=5,32 W; Ci=737 pF; Li=2.6 µH.

- Sensor input circuit: Vt=14.4 V; It=32.3 mA; Ca=600 nF; La=36 mH

〈 Any FM Approved FISCO barrier may be used that meets the following requirements:

Voc or Vt

≤ 17,5 V; Ioc or It ≤ 380 mA; Poc or Pt ≤ 5,32 W

When installing this equipment, follow the manufacturer s installation drawing.

Installation should be in accordance with ANSI/ISA RP 12 .06.01 Installation of Intrinsically Safe Systems for

Hazardous (Classified) Locations and the National Electrical Code (ANSI/NFPA 70).

Associated apparatus connected to the FISCO barrier must not use or generate more than 250 Vrms

o

r Vdc.

〈 Resistance between FISCO Intrinsically Safe Ground and earth ground must be less than 1.0 Ohm.

〈 The FISCO concept allows the interconnection of several I.S. apparatus not specifically examined in such

combination. The criterion for such interconnection is that the volta ge (Vmax), the current (Imax) and the

power (Pi) which I.S. apparatus can receive and remain intrinsically safe, considering faults, must be equal to

or greater that the voltage (Voc, Vt), the current (Ioc, It) and the power (Poc, Pt) which can be provided e by the

FM approved FISCO barrier. In addition, the maximum unprotected residual capacitance (Ci) and inductance

(Li) of each apparatus (other than the terminator) connected to the Fieldbus must be less than or equal to 5nF

and 10 H respectively.

〈 In each I.S. Fieldbus segment only one active source, normally the FM Approved FISCO barrier, is allowed

to provide the necessary power for the Fieldbus system. All other equipment connected to the bus cable has to

be passive (not providing energy to the system), except to a leakage current of 50 A for each connected

device. Seperately powered equipment needs a galvanic isolation to insure that the I.S. Fieldbus circuit

remains passive.

〈 The cable used to interconnect the devices needs to comply with the following parameters:

Loop resistance R : 15 150 /km; Inductance per unit length L : 0,4 1 mH/km

Capacitance per unit length C : 80 200 nF/km

(C = C line/line + 0,5 C line/screen if both line are floating)

(C = C line/line + C line/screen if the screen is connected to one line)

Length of spur cable: max. 30 m

Length of trunk cable: max. 1 km

Length of splice : max. 1 m

WARNING

- Substitution of components may impair Intrinsic Safety

- To prevent ignition of flammable or combustible atmospheres, disconnect power before servicing or read,

understand and adhere to the manufacturer s live maintenance procedures.

Unclassified Location

Classified Location

Division 1

FM Approved

FISCO barrier

Voc (Vt) ¡Ü17,5 V

Ioc (It)

¡Ü 380 mA

Poc (Pt)

¡Ü 5,32 W

FM Approved

Terminator

R = 90..100

C = 0..2,2 F

EXA

PH202S-F

& PH202S-P

Sensor

Connections

Max. cablelength: 60 mtr.

Cable dia. : 3 1 2 mm.

FM Class I, DIV. 1, Group ABCD

T3B for ambient temp.

≤ 55 ϒC

T4 for ambient tem

p

. ≤ 40 ϒC

IM 12B6C3-E-E

Specification 2-11

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S-F & PH202S-P

No revision to drawing without prior

FM Approval

Title : FM Control Drawing PH202S-F & PH202S-P (Intrinsic safe Entity

concept)

Number : FF1-PH202S-00 Page : 8 of 10

Revision : 5.4

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

〈 Sensor(s) are of a passive type to be regarded as ’simple apparatus’, devices which

neither store nor generate voltages over 1. 5 V, currents over 0.1 A, power over 25 mW or

energy over 20 µJ, or are FM Approvals entity approved and meet connection

requirements.

〈 Electrical data of the EXA PH202S-F & PH202S-P:

- Supply circuit:

Maximum input voltage Vmax=24 V

Maximum input current Imax=250 mA

Maximum input power Pi=1.2 W

Effective internal capacitance Ci=737 pF; Effective internal inductance Li=2.6

µH.

- Sensor input circuit:

Maximum output voltage Vt=14.4 V; Maximum output current It= 32.3 mA

Maximum allowed external capacitance Ca=600 nF

Maximum allowed external inductance La= 36 mH

〈 Any FM Approved barrier may be used that meets the following requirements:

Voc or Vt

≤ 24 V

Ioc or It ≤ 250 mA

Poc or Pt

≤ 1.2 W

Ca

? 737 pF + Ccable; La ? 2.6 µH + Lcable

When installing this equipment, follow the manufacturer s installation drawing.

Installation should be in accordance with ANSI/ISA RP 12.06.01 Installation of Intrinsically

Safe Systems for Hazardous (Classified) Locations and the National Electrical Code

(ANSI/NFPA 70).

Associated apparatus connected to the barrier must not use or generate more than

250 Vrms

or Vdc.

〈 Resistance between Intrinsically Safe Ground and earth ground must be less than 1.0

Ohm.

WARNING

- Substitution of components may impair Intrinsic Safety

- To prevent ignition of flammable or combustible atmospheres, disconnect power

before servicing or read, understand and adhere to the manufacturer s live

maintenance procedures.

Unclassified Location

Classified Location

Division 1

FM Approved

barrier

Voc (Vt) ¡Ü24 V

Ioc (It)

¡Ü 250 mA

Poc (Pt)

¡Ü 1,2 W

Ca

¡Y 737pF+ Ccable

La

¡Y 2,6 H + Lcable

I.S.

certified

Terminator

EXA

PH202S-F

& PH202S-P

Sensor

Connections

Max. cablelength: 60 mtr.

Cable dia. : 3 1 2 mm.

FM Class I, DIV. 1, Group ABCD

T3B for ambient temp. ≤ 55 ϒC

T4 for ambient tem

p

. ≤ 40 ϒC

IM 12B6C3-E-E

2-12 Specification

Stamp Company : Stamp Certification Institute :

Signature : Remarks :

Model EXA PH202S-B & PH202S-D

No revision to drawing without prior

FM Approval

Title : FM Control Drawing PH202S-B & PH202S-D (Non-incendive Entity

concept)

Number : FF1-PH202S-00 Page : 10 of 10

Revision : 5.4

YOKOGAWA EUROPE B.V.

Date : 01/07/2004

〈 Sensor(s) are of a passive type to be regarded as ’simple apparatus’, devices which neither store nor

generate voltages over 1.5 V, currents over 0.1 A, power over 25 mW or energy over 20

µJ, or are FM

Approvals entity approved and meet connection requirements.

〈 Electrical data of the EXA PH202S-B & PH202S-D:

- Supply circuit: Vmax=32 V; Pi=1.2 W; Ci= 737 pF; Li= 2.6 H

- Sensor input circuit: Vt=14.4 V; It=32.3 mA; Ca=600 nF; La=36 mH

When installing this equipment, follow the manufacturers installation drawing.

Installation shall be in accordance with Article 501.4(B) of the National Electrical Code (ANSI/NFPA 79).

Nonincendive field wiring may be installed in accordance with Article 501.4(B)(3)

〈 Grounding shall be in accordance with Article 250 of the National Electrical code.

WARNING

- Substitution of components may impair suitability for Division 2.

- Do not remove or replace while circuit is live unless area is know to be non -hazardous

- Explosion Hazard — Do not disconnect equipment unless area is know to be non -hazardous

- Do not reset circuit breaker unless power has been removed from the equipment or the area is know to be non -

hazardous

Unclassified Location

Classified Location

Division 2

FM Approved

Power Supply

Voc

¡Ü 32 VDC

FM Approved

Terminator

R = 90..100

C = 0..2,2 F

EXA

PH202S-B

& PH202S-D

Sensor

Connections

Max. cablelength: 60 mtr.

Cable dia.: 3 12 mm.

FM Class I, DIV. 2, Group ABCD

T3B for ambient temp.

≤ 55 ϒC

T4 for ambient tem

p

. ≤ 40 ϒC

IM 12B6C3-E-E

Specification 2-13

IM 12B6C3-E-E

3-1 Installation and wiring

3. INSTALLATION AND WIRING

3-1. Installation and dimensions

3-1-1. Installation site

The EXA converter is weatherproof and can be installed inside or outside. It should, however, be installed
as close as possible to the sensor to avoid long cable runs between sensor and converter. In any case, the
cable length should not exceed 50 meters (162 feet). Select an installation site where:

• Mechanical vibrations and shocks are negligible

• No relay/power switches are in the direct environment

• Access is possible to the cable glands (see figure 3-1)

• The transmitter is not mounted in direct sunlight or severe weather conditions

• Maintenance procedures are possible (avoiding corrosive environments)

The ambient temperature and humidity of the installation environment must be within the limits of the
instrument specifications. (See chapter 2).

3-1-2. Mounting methods

Refer to figures 3-2 and 3-3. Note that the EXA converter has universal mounting capabilities:

• Panel mounting using two (2) self-tapping screws

• Surface mounting on a plate (using bolts from the back)

• Wall mounting on a bracket (for example, on a solid wall)

• Pipe mounting using a bracket on a horizontal or vertical pipe (maximum pipe diameter 50 mm)

Fig. 3-2. Panel mounting diagramFig. 3-1. Housing dimensions and layout of

glands

Spacing panel
cut-out dimension

162 (6.4)

180 (7)

30 (1.2)

77 (3)

115 (4.5)

56 ±0.2

(2.2”)

1/2”
supply

M6 bolts (2X)

1/2”
input

min. 203

(min. 8.0)

154

(6.06)

2x ø4
(0.16)

30 (1.18)

30 (1.18)

172

(6.77)

min. 229

(min. 9.0)

Unit: mm (inch)

IM 12B6C3-E-E

Figure 3-4. Internal view of EXA wiring compartment

Figure 3-3. Wall and pipe mounting diagram

Pipe mounting
(vertical)

Wall mounting

Pipe mounting
(horizontal)

2” ND. pipe

56

(2.20)

2x ø6.5

(0.26)

4x ø10

(0.4)

70

(2.75)

115

(4.5)

92

(3.6)

200

(7.87)

Option /U: universal pipe/wall mounting kit

Installation and wiring 3-2

IM 12B6C3-E-E

3-3 Installation and wiring

3-2. Preparation

Refer to figure 3-4. The power/output connections and the sensor connections should be made in
accordance with the diagram on page 3-6. The terminals are of a plug in style for ease of mounting.

To open the EXA 202 for wiring:

1. Loosen the four frontplate screws and remove the cover.

2. The terminal strip is now visible.

3. Connect the power supply. Use the gland on the left for this cable.

4. Connect the sensor input, using the gland on the right (see fig. 3-5). Switch on the power. Commission
the instrument as required or use the default settings.

5. Replace the cover and secure frontplate with the four screws.

6. Connect the grounding terminals tp protective earth.

7. The optional hose connection is used to guide the cables comming from an immersion fitting through
aprotective plastic tubing to the transmitter.

3-2-1. Cables, terminals and glands

The PH202 is equipped with terminals suitable for the connection of finished cables in the size range: 0.13
to 2.5 mm (26 to 14 AWG). The glands will form a tight seal on cables with an outside diameter in the
range of 7 to 12 mm (9/32 to 15/32 inches).

Figure 3-5. Glands to be used for cabling

SENSOR

CABLE GLAND

POWER/OUTPUT

CABLE GLAND

GROUNDING TERMINAL

Sensor cable
gland

Power/Output
cable gland

Grounding terminal

IM 12B6C3-E-E

Figure 3-6. System configuration

3-3. Wiring of sensors

3-3-1. General precautions

Generally, transmission of signals from pH sensors is at a very low voltage and high impedance level. Thus
a lot of care must be taken to avoid interference. Before connecting sensor cables to the transmitter make
sure that next conditions are met:
– the sensor cables are not mounted in tracks together with high voltage and or power switching cables
– only standard coaxial electrode cables or extension cable are used
– the transmitter is mounted within the distance of the sensor cables (max. 10 m)
– the setup is kept flexible for easy insertion and retraction of the sensors in the fitting.

3-3-2. Additional precautions for installations in hazardous areas

Make sure that the total of capacitances and inductances connected to the input terminals of the EXA
PH202S do not exceed the limits given in the certificate.
This sets a limit to the cable and extensions used.
– The intrinsic safe version of the PH202S instrument can be mounted in Zone 1.
– The sensors can be installed in Zone 0 or Zone 1 if a safety barrier according to the limits given in the

system certificate is used.

– Ensure that the total of capacitances and inductances connected to the terminals of the EXA PH202S do

not exceed the limits given in the certificate of the safety barrier or distributor.
– The cable used should preferably have a BLUE colour or marking on the outside.
– Installation for (sensors in Zone 0 or 1):
Generally, the distributor with input/output isolation has no external earth connection. If there is an earth

connection on the distributor and the external connection of the transmitter is connected to “protective”

earth, the shield of the 2-wire cable may NOT be connected to “protective” earth at the distributor too.

1 2

18

0

10

0

0

NO MODEYES

>

ENT

>

FAILHOLD

YES

NO

ENT

MEASURE

MAN.CAL
DISPLAY

HOLD

YOKOGAWA

MODE

TEMP

AUT.CAL

TEMP.MAN.

pH

Sensors

Recorder

Distributor

Computer

Hand Held
Communicator

Output/supply

Input

2 , 5 or 10 m

Safety Barrier
PH202S only

CURRENT OUTPUT

ref

pH/ORP temp.

Installation and wiring 3-4

IM 12B6C3-E-E

3-5 Installation and wiring

3-3-3. Installation in: Hazardous Area-Non-Incendive

The EXA PH202S-N may be installed in a Category 3/ Zone 2/ Div.2 area without the use of safety barriers.
Maximum permissible supply voltage 31.5V

3-3-4. Liquid earth

In all circumstances, the sensor side of the measuring loop must be grounded to the measuring liquid. The
EXA PH202S uses advanced differential high impedance input circuits. This technique calls for a grounding
to the liquid. In addition to that the sensor checking circuits also use the liquid earth for measurement of
impedance of the sensors. All Yokogawa fittings have provisions for this connection. It is usually called liquid
earth in all our manuals.
A separate connection should be made to the terminal numbered 14 in all cases to get a proper and stable
measuring loop.

3-3-5. Access to terminal and cable entry

1. To access terminals remove the front cover of the EXA PH202S by releasing the 4 captive screws.

2. Thread the sensor cables into the connection space and connect the cables to the terminals as indicated
in the wiring diagram. Make sure all connections are firm and do not touch each other.

3. Screw the gland securely and tighten it to keep out moisture. DO NOT use a
wrench to tighten the nut.

4. The optional hose connection is used to guide the cables coming from an immersion fitting through a
protective plastic tubing to the transmitter.

3-4. Wiring of power supply

3-4-1. General precautions

Do not activate the power supply yet. First make sure that the DC-power supply is according
to the specifications given.

DO NOT USE ALTERNATING CURRENT OR MAINS POWER SUPPLY! !

The cable leading to the distributor (power supply) or safety barrier transports power to and output signal
from the transmitter. Use a two conductor shielded cable with a size of at least 1.25 mm

2

and an outside
diameter of 7 to 12 mm. The cable gland supplied with the instrument accepts these diameters. The
maximum length of the cable is 2000 metre, or 1500 metres when using the communications. This ensures
the minimum operating voltage for the instrument.

Grounding:

• If the transmitter is mounted on a grounded surface (e.g. a metal frame fixed in the soil) the shield of the

2-wire cable may NOT be connected to ground at the distributor.

• If the transmitter is mounted on a non-conducting surface (e.g. a brick wall) it is recommended to ground

the shield of the 2-wire cable at the distributor end.

WARNING

IM 12B6C3-E-E

3-4-2. Connection of the power supply

The terminal strip is accessed as was described in §3-2-1. Use the left-hand gland to insert the supply/
output cable to the transmitter. Connect the supply to the terminals marked +, - and G as is indicated in
figures 3-8 and 3-9.

3-4-3. Switching the instrument on

After all connections are made and checked, the power can be switched on from the distributor. Observe
the correct activation of the instrument at the display. If for any reason the display does not indicate a value,
consult the trouble shooting section.

Red

ref

pH/ORP

temp.

Green

Yellow

Colour code

rd bl

rd
bl
bk
wt

=
=
=
=

red
blue
black
white

11 12 14 17 13

15 16HIGH I

MPLOW IMP

TEMP LE INPUT 2 INPUT

1

rd bl

SINGLE
ELECTRODES

CONNECTION DIAGRAM FOR SENSORS

Blue

Combi
pH/Ref

Comb

i

Orp/Re

f

temp.

Green

Colour code

COMBINED
ELECTRODES

rd

bk

11 12 14 17 13

15 16HIGH I

MPLOW IMP

TEMP LE INPUT 2 INPUT

1

wtbl

bl

rd

bk

bl rd

rd
bl
bk
wt

=
=
=
=

red
blue
black
white

12B6C3-06

CONNECTION DIAGRAM FOR SENSOR

link

link

Fig. 3-7. Connection diagrams

ORP/Ref

Installation and wiring 3-6

IM 12B6C3-E-E

3-7 Installation and wiring

3-5. Wiring the sensor system

3-5-1. Impedance measurement jumper settings

NOTE:
It is important to decide first which application and which settings are appropriate for the installation. This
decision is best made before the jumpers are installed, because the cables will rest beside the jumpers in
their installed positions.

Table 3-1. Impedance measuring jumpers

Figure no. Jumper Settings Jumper Settings Application & Sensor Connections

Input #1 Input #2

1 High Impedance Low Impedance Normal pH sensors
Glass sensor on Input #1
Reference sensor on Input #2

2 High Impedance High Impedance Special electrodes using
2 glass sensors
(e.g. Pfaudler 18)

3 Low Impedance High Impedance ORP (pH compensated) and/or rH
metal sensor on Input #1
pH glass (as reference) on Input #2

4 Low Impedance Low Impedance ORP (Redox measurement)
metal sensor on Input #1
Normal reference on Input #2

For convenience insulated jumper links are provided. Ordinary wire links can also be used, and are just as
effective.

The following four jumper figure illustrations (figure 3-8) show the jumper positions related to the figure
numbers in the above table.

11 12 14 17 13 15 16

HIGH IMPLOW IMP

HART SUPPLY TEMP LE

INPUT 2

INPUT 1

11 12 14 17 13 15 16

HIGH IMP

LOW IMP

HART SUPPLY TEMP LE INPUT 2 INPUT 1

11 12 14 17 13 15 16

HIGH IMP

LOW IMP

HART SUPPLY TEMP LE

INPUT 2

INPUT

1

11 12 14 17 13 15 16

HIGH IMP

LOW IMP

HART SUPPLY TEMP LE

INPUT 2 INPUT 1

1

2

3

4

Fig. 3-8. Jumper positions

IM 12B6C3-E-E

Figure 3-9. Terminal identification labels

3-6. Sensor wiring

Refer to figure 3-10, which includes drawings that outline sensor wiring.

The EXA analyzers can be used with a wide range of commercially available sensor types, both from
Yokogawa and other manufacturers. The sensor systems from Yokogawa fall into two categories; the ones
that use a fixed cable and the ones with separate cables.

To connect sensors with fixed cables, simply match the terminal numbers in the instrument with the
identification numbers in the instrument on the cable ends.

The separate sensors and cables are not numbered, but instead use a color-coding system. The electrodes
have a colored band incorporated in the label on the connection cap:

• Red for measuring electrodes (both pH and ORP)

• Yellow for reference electrodes

• Blue for combined sensors with both measuring and reference elements in the same body

• Green for temperature sensors

The recommended procedure is to color-code each end of the cables to match the sensors with the color
strips provided with each cable. This provides a quick way to identify the ends of the cables belonging to
a particular sensor when they are installed. (The procedure for fixing the identification labels is described in
detail in the instruction sheet provided with the cable.)

11 12 14 17 13 15 16

HIGH IMPLOW IMP

HART SUPPLY TEMP LE INPUT 2 INPUT 1

Installation and wiring 3-8

3-9 Installation and wiring

IM 12B6C3-E-E

3-6-1. Connection cable

There are two types of connection cable, one for single sensors and one for combined sensors. The former
is a coaxial cable and has only two connections.

• Red to measuring element

• Blue to screen (shield)

The latter is a triaxial cable with three connections, (it has an extra white wire termination) these wires are
connected:

• Red to measuring element

• Blue to reference

• White to screen (shield)

To connect the other sensor systems, follow the general pattern of the terminal connections as listed below:
11 & 12 Temperature compensation resistor input
13 Input no. 2 (normally the reference element)
17 Screen (shield) for input no. 2
14 Liquid earth (solution ground) connection
15 Input no. 1 (normally the measuring element)
16 Screen (shield) for input no. 1

Figure 3-10a. Sensor wiring

*

*

*

*

12B6B3-03/1

12B6B3-03/3

*

*

*

12B6B3-03/2

pH transmitter

Green

Yellow

Red

Cable markers

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Glass (measure)
16 Shield
17 Shield

Red

Blue

Red

Black
Red

Blue
Blue

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Glass (measure)
16 Shield
17 Shield

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Glass (measure)
16 Shield
17

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Glass (measure)
16 Shield
17 Shield

Combined pH/ref sensors

Cable markers

Red

Blue
Blue
Black

Red
White

Green

Blue

FU20/FU25 4-in one sensor

Note: Connect cables to similarly marked
terminals: 11 to 11, 12 to 12, etc.

Retractable sensor assembly PR20

(Also PD20, PF20 & PS20)

NOTE:
Connect cables to similarly marked terminals: 11
to 11, 12 to 12, etc.

IM 12B6C3-E-E

Installation and wiring 3-10

Figure 3-10b. Sensor wiring

3-6-2. Sensor cable connection with special grommet

In order to seal multiple sensor cables into EXA, a special grommet is provided that is designed to
accommodate one, two or three sensor cables (5 mm dia.) plus a liquid earth cable (2.5 mm dia.). In the
pack with the grommet are blanking pieces to close any unused holes. When correctly assembled, the
grommet maintains the IP65 (NEMA 4X) rating of the EXA PH202 housing.

Refer to figure 3-5 to assemble the grommet connections:

1. First remove the nut and standard rubber seal from the selected gland

2. Discard the seal. This will be replaced later by the special grommet

3. Thread the cables through the nut and the gland

4. Connect the cables to their designated terminals

5. Arrange the cables to avoid tangles and insert the grommet between the gland and the nut

6. The grommet is split to permit the cables to be mounted after connection. (This also ensures even length
adjustment.)

7. Ensure that any unused holes are filled with the blanking pieces

8. Tighten the nut to form a firm seal. (Hand-tight is sufficient.)

NOTE:
The special gland is intended to be used to seal the multiple cables from the Yokogawa flow fittings such as
FF20 and FP20. The designated cables are WU20 sensor cables, which are approximately 5 mm (0.2 “) in
diameter, and 82895002 liquid earth cables, which are approximately 2.5 mm (0.1 “) in diameter.

For sensor systems using a single cable, like the FU20 (FU25) and the PR20, PD20, PF20 and PS20, the
standard gland will accommodate the cable adequately. Single cables between approximately 7 mm and 12
mm (0.28 “ and 0.47 “) can be sealed properly with these glands.

*

*

*

12B6B3-09
Separate electrodes
ORP/REF Electrode

*

*

12B6B3-08

Combined ORP/pH Electrode

Separate electrodes

ORP/REF electrode

Red

Yellow

Cable markers

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Metal (measure)
16 Shield
17 Shield

Red

Black

Red

Blue
Blue

11 Temperature
12 Temperature
13 Reference
14 Solution ground(ORP)
15 pH
16 Shield
17

ORP/rH wiring

Note: ORP and or rH setting in service

code 02.

11 Temperature
12 Temperature
13 Reference
14 Solution ground
15 Metal (measure)
16 Shield
17 Shield

Blue

Blue

Red

White

Cable markers

Combined ORP/pH electrode

Notes

1. A temperature sensor maybe
connected to 11 & 12, for
temperature indication.

2. See section 5-3-1 for
impedance checking of glass
reference sensors.

IM 12B6C3-E-E

3-11 Installation and wiring

3-6-3. Sensor cable connections using junction box (BA10) and extension cable (WF10)

Where a convenient installation is not possible using the standard cables between sensors and converter, a
junction box and extension cable may be used. The Yokogawa BA10 junction box and the WF10 extension
cable should be used. These items are manufactured to a very high standard and are necessary to ensure
that the specifications of the system are not compromised. The total cable length should not exceed
50 metres (e.g. 5 m fixed cable and 45 m extension cable). In the case of systems using dual high
impedance sensors (e.g. Pfaudler 18), then the cable length is restricted to 20 metres (fixed cable only, no
extension with WF10).

17 Overall Screen

11

12

12

13

14

14 16

15

13

14141615

17

11

17

11 Red

12 Blue

15 Core 16 Screen
White Co-axial cable

13 Core 14 Screen

Brown Co-axial Cable

14 (screen)

17 (overall screen)

12 (blue)

11

(red)

13 (core

)

16 (screen

)

15 (core)

Co-axial cable

(white)

Co-axial cable

(brown)

WF10 Cable

EXA

pH TRANSMITTER / CONVERTER

11

12

13

14

15

16

17

11

12

13

14

15

16

17

Fig. 3-11. Connection of WF10 extension cable and BA10/BP10 junction box

NOTE: See page 3-12 for termination for WF10 cable in combination with EXA pH.

3-6-4. Connection VP type sensor

> Connect ions norm al

p

H

A-15
B-13
C­D-14
E-11
F-12
S-3 or 63

pH

ref

LE

temp

> Connections differential pH

A-15
B-14
C-13
D-17
E-11
F-12
S-3 or 63

pH

pH ref

LE

temp

IM 12B6C3-E-E

Installation and wiring 3-12

Extension cable may be purchased in bulk quantities, cut to length. Then it is necessary to terminate the
cable as shown below.

Termination procedure for WF10 cable.

1. Slide 3 cm of heat shrink tube (9 x 1.5) over the cable end to be terminated.

2. Strip 9 cm of the outer (black) insulating material, taking care not to cut or damage internal cores.

3 cm

heat shrink

9 cm

remove insulation

Fig. 3-12a.

3. Remove loose copper screening, and cut off the cotton packing threads as short as possible.

4. Strip insulation from the last 3 cm of the brown, and the white coaxial cores.

3 cm

cotton threads

Fig. 3-12b.

5. Extract the coaxial cores from the braid, and trim off the black (low-noise) screening material as short as
possible.

6. Insulate the overall screen and the 2 coaxial screens with suitable plastic tubing.

7. Strip and terminate all ends with suitable (crimp) terminals and identify with numbers as shown.

11
12

13

15

16
17

14

Fig. 3-12c.

8. Finally shrink the overall heat shrink tube into position.

IM 12B6C3-E-E

4-1 Operation

4. OPERATION; DISPLAY FUNCTIONS AND SETTING

4-1. Operator interface

This section provides an overview of the operation of the EXA operator interface. The basic procedures
for obtaining access to the three levels of operation are described briefly. For a step-by-step guide to data
entry, refer to the relevant section of this user’s manual. Figure 4-1 shows the EXA operator interface.

LEVEL 1: Maintenance

These functions are accessible by pushbutton through a flexible front cover window. The functions make up
the normal day-to-day operations that an operator may be required to complete. Adjustment of the display
and routine calibration are among the features accessible in this way. (See table 4-1).

LEVEL 2: Commissioning

A second menu is exposed when the EXA front cover is removed and the display board is revealed. Users
gain access to this menu by pressing the button marked

*

in the lower right of the display board. This menu
is used to set such values as the output ranges and hold features. It also gives access to the service menu.
(See table 4-1).

LEVEL 3: Service

For more advanced configuration selections, press the button marked

*

, then press “NO” repeatedly until
you reach SERVICE. Now push the “YES” button. Selecting and entering “Service Code” numbers in the
commissioning menu provide access to the more advanced functions. An explanation of the Service Codes
is listed in chapter 5 and an overview table is shown in chapter 10.

Table 4-1. Operations overview

Routine Function Chapter
Maintenance AUT CA• Calibration with programmed buffer solutions 6
MAN CAL Calibration with other buffer solutions 6
SAMPLE Grab sample calibration 6
DISPLAY Read auxiliary data or set message display 4
MAN.IMP Manual start of impedance check 5
TEMP Select automatic or manual compensation 5
HOLD Switch hold on/off (when activated) 5
Commissioning RANGE Adjust the output range 5
SET HOLD Activate the hold function 5
Service SERVICE Fine tune the specialized functions of the 5
(Access to coded entries converter
from the commissioning
level)

NOTE:
All three levels may be separately protected by a password. See Service Code 52 in chapter 5 Service
Code table for details on setting passwords.

mA

IM 12B6C3-E-E

Operation 4-2

Figure 4-1. PH202 operator interface

4-2. Explanation of operating keys
MODE key This key toggles between the measuring and maintenance modes. Press once to obtain

access to the maintenance function menu.

AUTO CAL
MAN CAL
DISPLAY
SETPOINT
WASH
MAN.IMP
TEMPERATURE
HOLD
Press again to return to the measuring mode (press twice when hold is activated)

YES/NO keys These are used to select choices from the menu.

YES is used to accept a menu selection.

NO is used to reject a selection, or to move ahead to the next option.

DATA ENTRY keys

( )

is used as a “cursor” key. Each press on this key moves the cursor or flashing digit

one place to the right. This is used to select the digit to be changed when entering
numerical data.

is used to change the value of a selected digit. Each press on this key increases the

value by one unit. The value can not be decreased, so in order to obtain a lower
value, increase past nine to zero, then increase to the required number.

When the required value has been set using the > & ^ keys, press ENT to confirm the

data entry. Please note that the EXA does not register any change of data until the
ENT key is pressed.

* key This is the commissioning mode key. It is used to obtain access to the commissioning

menu. This can only be done with the cover removed or opened. Once this button has

been used to initiate the commissioning menu, follow the prompts and use the other keys

as described above.

OUTPUT
SET HOLD

SERVICE

ENT

HOLD FAIL

YES NO

ENT

MAN.CAL

DISP LAY

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CA L

TEMP.MAN.

pH

mV

MEA SURE

12B6C3-13

FRONT EXA PH20

2

WASH

Output hold flag

Manual temperature
compensation flag

Fail flag

Menu pointer flags

Commissioning
function menu

Commissioning
mode access key

Measure/Maintenance
mode key

Broken line indicates area that can be
seen through front cover

Adjustment keys
> : Choose digit to

adjust
^ : Adjust digit
ENT : Confirm change

Selection keys
YES : Accept setting
NO : Change setting

Key prompt flags

Message display

Main display

Units

IM 12B6C3-E-E

4-3 Operation

4-3. Setting passcodes

4-3-1. Passcode protection

In Service Code 52, EXA users can set passcode protection for each one of the three operating levels, or
for any one or two of the three levels. This procedure should be completed after the initial commissioning
(setup) of the instrument. The passcodes should then be recorded safely for future reference.

When passcodes have been set, the following additional steps are introduced to the configuration and
programming operations:

Maintenance

Press MODE key. The display shows 000 and *PASS*
Enter a 3-digit passcode as set in Service Code 52 to obtain access to the Maintenance Mode

Commissioning

Press

*

key. The display shows 000 and *PASS*

Enter a 3-digit passcode as set in Service Code 52 to obtain access to the Commissioning Mode.

Service

From the commissioning menu, select *Service by pressing YES key. The display shows 000 and *PASS*
Enter a 3-digit passcode as set in Service Code 52 to obtain access to the Service Mode.

NOTE:
See Service Code 52 for the setting of passcodes.

4-4. Display examples

The following pages show the sequence of button presses and screens displayed when working in some
standard configurations.

More or less options will be made available by the configuration of some service codes. For instance the
impedance measurement screens do not appear when impedance checking is switched off in service
codes 03 and 04.

mA

IM 12B6C3-E-E

Operation 4-4

NO

YES

pH

pH

pH

YES

pH

YES

NO

pH

pH

pH

YES

(See Temp
menu

Chapter 5)

YES NO

TEMP.

MODE

NO

YES

YES

NO

NO

NO

(See Auto
calibration
Chapter 6)

(See Manual
calibration

Chapter 6)

YES

NO

YES NO

YES NO

MEASURE

MAN.CA

L

DISPLA

Y

HOLD

TEMP.

AUT.CA

L

MAN.CA

L

DISPLA

Y

AUT.CA

L

MAN.CA

L

(See Sample
calibration
Chapter 6)

pH

pH

pH

pH

pH

pH

NO

NO

Offset
(as. pot. or
zero point)

Efficiency

(slope)

Press YES to fix

the selected second

line of display

YES

NO

YES

NO

DISPLAY

NO

NO

NO

NO

Display Access

Impedance of input

1

Impedance of input

2

Process temperatur

e

Software release number

YES

YES

NO

YES

NO

YES

NO

YES

NO

DISPLAY

DISPLA

Y

DISPLA

Y

DISPLAY

NO

YES

(See Manual
Impedanc

e

check Chapter 5)

NO

OUTPUT
SET HOLD

SERVICE

ENT

FAIL

YES NO

ENT

MAN.CAL

DISPLAY

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CAL

TEMP.MAN.

pH

mV

MEASURE

DISPLAY

4-5. Display functions

4-5-1. Display functions pH (default)

IM 12B6C3-E-E

4-5 Operation

pH

pH

pH

NO

pH

pH

YES

NO

YES

NO

TEMP.

HOLD

NO

YES

YES

See Temp
Menu
chapter

5

See Hold
Menu
chapter

5

DATE

pH

pH

pH

TIME

CAL -1

VALU

E

Service Code 01 Set for pH

.
Service Code 02 Set for ORP
on parameter 2.

DISPLAY

DISPLA

Y

DISPLA

Y

DISPLA

Y

DISPLA

Y

"Logbook Scrolling"

Logbook data is availabl

e

only in instruments with

"PIN" for advanced function

The display can give informatio

n

about calibrations performe

d

with date and time.

The example below show

s

Asymmetry Potential

.

Scrolling of Data is also

available on Slope.

As Pot ORP

Impedance Input

1

Impedance Input 2

When these function

s

are enabled in Servic

e

Codes.

Measurin

g

Mod

e

As Po

t

Display

2

pH

YES

NO

DISPLAY

DISPLAY

DISPLA

Y

NO

NO

YES

NO

YES

NO

pH

pH

YES

DISPLAY

DISPLAY

DISPLAY

DISPLAY

DISPLA

Y

DISPLA

Y

YES

NO

NO

NO

NO

NO

NO

pH

NO

MODE

NO

NO

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

pH

pH

pH

pH

YES

NO

YES

NO

YES

NO

YES

NO

pH

pH

pH

pH

pH

pH

MAN.CAL

MEASURE

MAN.CA

L

DISPLA

Y

HOLD

TEMP.

AUT.CA

L

AUT.CAL

DISPLAY

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES NO

ENT

YES NO

ENT

YES NO

ENT

YES NO

ENT

YES NO

ENT

NO

NO

YES

pH

NO

YES

See Man.
Imp. Check
chapter

5

Back to

the Top

YES

NO

4-5-2. Display functions pH (ORP)

mA

mA

IM 12B6C3-E-E

Operation 4-6

4-5-3. Display functions pH (rH)

pH

YES

NO

DISPLAY

TEMP.

HOLD

NO

YES

YES

NO

YES NO

See Hold Menu
Chapter

5

See Temp Menu
Chapter

5

YES

NO

pH

pH

MAN.CAL

NO

NO

YES

pH

MEASURE

MAN.CA

L

DISPLA

Y

HOLD

TEMP

.

AUT.CAL

NO

YES

AUT.CAL

NO

MODE

DISPLAY

NO

DISPLAY

DISPLAY

DISPLAY

mV

DISPLAY

DISPLAY

DISPLAY

DISPLAY

DISPLAY

NO

NO

NO

NO

NO

NO

mV

As Pot ORP

Impedance

Input

1

Impedance

Input

2

Softwar

e

Releas

e

Version

NO

Slope

pH Senso

r

As Po

t

pH Senso

r

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

pH

pH

pH

pH

pH

pH

NO

YES

NO

rH Display

Curren

t

Outpu

t

YES

NO

pH

pH

12B6B3-22

See Auto Cal
Chapter

6

See Man Ca

l

Chapter 6

See Man Cal
Chapter

6

YES

YES NO

YES NO

YES

YES

YES

pH

pH

pH

pH

Service Code 01 Set for pH.
Service Code 02 Set to rH

on parameter 2.

NO

Temp Display

NO

NO

YES

pH

NO

YES

See Man. Imp.

check Chapter 5

mA

mA

IM 12B6C3-E-E

5-1 Parameter setting

5. PARAMETER SETTING

5-1. Maintenance mode

Standard operation of the EXA instrument involves use of the maintenance (or operating) mode to set up
some of the parameters.

Access to the maintenance mode is available via the six keys that can be pressed through the flexible
window in the instrument cover. Press the MODE-key once to enter this dialog mode.
NOTE:
At this stage the user will be prompted for pass code where this has been previously set up in service code
52 in chapter 5.

Automatic calibration See “calibration” section 6.

Manual calibration See “calibration” section 6.

Sample calibration See “calibration” section 6.

Display setting See “operation” section 4.

Manual impedance check See “parameter setting” §5-1-4 and §5-3-5 code 51.

Temperature Set automatic or manual compensation and adjust manual reading (when

pH is set in section 5 service code 01). See adjustment procedure in

§5-1-1.
Set automatic reading (when ORP is set in Section 5, service code 01).
See adjustment procedure §5-1-2.

Hold Manually switch on/off HOLD (when enabled in commissioning menu

section). See adjustment procedure in §5-1-3.

mA

IM 12B6C3-E-E

Parameter setting 5-2

5-1-1. Manual temperature selection and adjustment

pH selected in service code 01.

TEMP.MAN.

ENT

12B6C3-23

NO

YES

pH

AUT.CAL

YES

NO

pH

TEMP.

pH

OUTPUT
SET HOLD

SERVICE

ENT

FAIL

NO MODEYES

YOKOGAWA

MODE

Measure

MODE

NO

NO

NO

NO

YES

NO

YES

pH

NO

YES

pH

NO

YES

(pH Selected in Service Code 01)

Use

keys to

adjust and enter manual temperature settin

g

IM 12B6C3-E-E

5-3 Parameter setting

5-1-2. Process temperature measuring in ORP mode

ORP selected in service code 01.

MODE

mV

OUTPUT
SET HOLD

SERVICE

ENT

NO MODEYES

YOKOGAWA

MEASURE

12B6C3-24

NO

YES

mV

MAN.CAL

YES NO

TEMP.

mV

MODE

NO

NO

NO

YES

NO

YES

mV

NO

YES

mV

NO

YES

MEASURE

YES

NO

mV

YES

5.2 Process Temperature Measuring in ORP mode.

(ORP selected in Code 01)

Display return to
measuring mode with
temperature reading.

IM 12B6C3-E-E

Parameter setting 5-4

5-1-3. Manual activation of HOLD

MODE

pH

OUTPUT
SET HOLD

SERVICE

ENT

NO MODEYES

YOKOGAWA

M E A S U R E

12B6C3-25

pH

AUT.CAL

YES

NO

pH

MODE

NO

NO

NO

YES

NO

YES

pH

pH

HOLD

YES

NO

5.3 Manual Activation of Hold.

Note: The HOLD feature must first be activated in the commissioning mode section 5.2.

2

YES

NO

MEASURE

NO

YES

pH

NO

YES

NO

HOLD

mA

IM 12B6C3-E-E

5-5 Parameter setting

5-1-4. Manual impedance check

12B6C3-36

NO

YES

pH

AUT.CAL

YES

NO

pH

MODE

NO

NO

NO

NO

YES

pH

YES

NO

NO

YES

pH

5-1-4. Manual Impedance Check

Return to measuring

mode after updating

impedance chec

k

Note: The manual impedance start
is available when the sensor impedanc

e
measurement is enabled in Service
Code 3 and 4.
This enables the impedance data to be
updated immediately after a maintenance
event (e.g. replacing an

electrode).

YES

MODE

pH

OUTPUT
SET HOLD

SERVICE

ENT

NO MODEYES

YOKOGAWA

MEASURE

IM 12B6C3-E-E

Parameter setting 5-6

5-2. Commissioning mode

In order to obtain peak performance from the EXA, you must set it up for each custom application.

Output range mA output is set as default to 0 - 14 pH.

For enhanced resolution in more stable measuring processes, it may be desirable

to select 5 - 10 pH range, for example.
Service codes 31 and 35 can be used to choose output function on mA output.

Hold The EXA transmitter has the ability to “hold” the output during maintenance

periods. This parameter should be set up to hold the last measured value, or a
fixed value to suit the process.

Service This selection provides access to the service menu.

What follows are pictorial descriptions of typical frontplate pushbutton sequences for each parameter
setting function. By following the simple YES/NO prompts and arrow keys, users can navigate through the
process of setting range, hold and service functions.

mA

mA

IM 12B6C3-E-E

5-7 Parameter setting

5-2-1. Output range

NO

NO

NO

pH

pH

pH

pH

pH

pH

pH

pH

OUTPUT
SET HOLD

SERVICE

ENT

MAN.CAL
DISPL AY

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CAL

MEA SURE

Output Range

12B6C3-26

YES

ENT

YES

NO

pH

ENT

ENT

ENT

ENT

ENT

ENT

ENT

ENT

YES

NO

YES

NO

YES

NO

YES

Note: When rH or ORP is
enabled in codes 02 and 31,
the output range is set in
a similar way to pH

.

mA

IM 12B6C3-E-E

Parameter setting 5-8

5-2-2. Hold

YES

NO

YES

NO

YES

NO

YES

NO

NO

12B6C3-27

YES

YES

NO

YES

NO

YES

NO

YES

NO

YES

YES

NO

Hold

HOLD active
last measured

value.

HOLD deactivated, retur

n

to commissioning menu.

HOLD

YES

HOLD

pH

OUTPUT
SET HOLD

SERVICE

ENT

MAN.CAL
DISPL AY

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CAL

MEA SURE

YES

NO

NO

NO

mA

IM 12B6C3-E-E

5-9 Parameter setting

YES

NO

ENT

HOLD

HOLD value set,
return to commissioning
menu

.

HOLD

ENT

HOLD

ENT

HOLD

ENT

YES

Set HOLD "fixed value"
for mA1

.

Set HOLD “fixed value”
for mA Output

IM 12B6C3-E-E

Parameter setting 5-10

5-2-3. Service

ENT

YES

NO

YES

NO

YES

NO

NO

NO

NO

12B6C3-29

Service

ENT

ENT

ENT

YES

ENT

ENT

Example: Service Code 01

Select main parameter

for pH

for ORP

With the

>, ,ENT keys

>

ENT

pH

OUTPUT
SET HOLD

SERVICE

ENT

MAN.CAL
DISPLA Y

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CA

L

MEA SURE

Wait screen is displayed
briefly before returning
to commissionning menu

.

Wait screen is displayed
briefly before returning
to commissioning menu.

mA

mA

IM 12B6C3-E-E

5-3-1. Parameter specific functions

Code 1 pH/ORP Choose the main measuring parameter. The option of the ORP input is used with

an inert metal electrode as measuring sensor which gives a reading directly in
millivolts. This signal can then be interpreted to give information about the
oxidation state of the process solution, and derived information like the absence
of a compound (like Cyanide for example which is destroyed in oxidizing
solutions).

Code 2 PRM.2 Enable the use of a second measuring parameter simultaneously with pH (the

main parameter).
With the correct sensor (e.g FU20), ORP measurement is possible as parameter 2
With the same sensor, rH measurement is possible as parameter 2, this is
calculated from pH and ORP and is a value which gives the oxidizing power of
the solution while compensating for the effect of pH.

This function is particularly useful for applications where both the pH and

oxidation-reduction potential of the process need to be known. The availability of
both measurements in a single system is convenient.

Note that in both cases a suitable sensor combination is needed to make this

possible. The Yokogawa FU20 (4-in-1) sensor can be used for this purpose, or a
combination of individual sensors. Contact your local Yokogawa sales office for
advice regarding applications and sensor selection.

Code 3 & 4 Z1.CHK & The EXA PH202 has an impedance check capable of monitoring the impedance
Z2.CHK of all sorts of sensor systems. In order to “fine tune” this diagnostic tool it is

necessary to set it up to match the sensors used. The default settings give a
good setup for a conventional system comprising pH glass sensor and a
reference electrode, either as individual electrodes or as a combination style
sensor. The impedance limits will need to be adjusted to get the best from
systems using heavy duty, or fast response electrodes.

The impedance measuring system has a very wide span requirement. As it can

measure in k and also in G (109) there are hardware switches to set high
range (1M to 2 G) or low range (1k to 1M) measuring. As a default the
system is set to measure high impedances on input 1 (the one normally used for
the pH glass sensor input) and low impedances on input 2 (the one normally used
for the reference input). Examples of where these settings need to be changed
from the default, are Pfaudler enamel sensors which need two high impedance
settings, and Platinum sensors with a standard reference, which need two low
impedance settings.

The temperature compensation of the impedance measurement is for conven-

tional pH glass sensors. When other sensors are used, switch this feature off.

Code 5 CAL.CK The calibration checking feature, when enabled, gives security against entering

wrong calibration data. For example when aged sensors are due for
replacement, the EXA flags an error message and prevents a calibration being
completed where the subsequent measurement can only exhibit errors and drift.

Limits are set for the maximum permissible Asymmetry potential, and Slope.

5-11 Parameter setting

Parameter setting 5-12

Code Display Function Function detai• X Y Z Default values

Parameter specific functions

01 *PH.ORP Select main parameter pH 0

ORP 1

02 *PRM.2 Enable 2nd parameter Off 0 0 Off

ORP 1

rH 2

03 *Z1.CHK Impedance check 1 Low 0 1.1.1

High 1 High

Temp comp off 0

Temp comp on 1 On

Imp check off 0

Imp check on 1 On

*Z.L.x

 Low impedance limit Press NO to step through choice of units, 1 M

x = None, K, M or G press YES to select units, then use the

>, ^ ENT keys to set the value

*Z.H.x High impedance limit Press NO to step through choice of units, 1 G

press YES to select units, then use the

>, ^ ENT keys to set the value

04 *Z2.CHK Low 0 0.0.1 Low

High 1

Temp comp off 0 Off

Temp comp on 1

Imp check off 0

Imp check on 1 On

*Z.L.x Low impedance limit Press NO to step through choice of units, 100 

x = None, K, M or G press YES to select units, then use the

>, ^ ENT keys to set the value

*Z.H.x High impedance limit Press NO to step through choice of units, 200 k

press YES to select units, then use the

>, ^ ENT keys to set the value

05 *CAL.CK Calibration check Asymmetry check off 0 1.1

Asymmetry check on 1 On

Slope check off 0

Slope check on 1 On

06-09 Not used

IM 12B6C3-E-E

IM 12B6C3-E-E

5-13 Parameter setting

5-3-2. Temperature compensation and measuring functions.

Code 10 T.SENS Selection of the temperature compensation sensor. The default selection is

the Pt1000 Ohm sensor, which gives excellent precision with the two wire
connections used. The other options give the flexibility to use a very wide range
of other pH sensors.

Code 11 T.UNIT Celsius or Fahrenheit temperature scales can be selected to suit user preference.

Code 12 T.ADJ With the process temperature sensor at a stable known temperature, the

temperature reading is adjusted in the main display to correspond. The
calibration is a zero adjustment to allow for the cable resistance, which will
obviously vary with length.

The normal method is to immerse the sensor in a vessel with water in it, measure

the temperature with an accurate thermometer, and adjust the reading for
agreement.

Code 13 T.COMP Process compensation automatically allows for changes in the pH or ORP of the

process with temperature. The characteristic of each process will be different,
and the user should determine if this feature is to be activated, and what
compensation figure to choose.

The compensation is given in pH per 10 °C or mV per 10 ºC.

Example: For pure water with an alkali dose, (e.g. boiler feed water) a coefficient

of approx. 0.35pH can be expected. However, applications vary and
a simple test will determine what if any coefficient is suitable for the
process.

IM 12B6C3-E-E

Parameter setting 5-14

Code Display Function Function detai• X Y Z Default values

Temperature measuring and compensation functions

10 *T.SENS Temperature sensor Pt1000 0 0 Pt1000

Pt100 1

3kBalco 2

5k1 3

8k55 4

350 5

6k8 6

PTC10k 7

11 *T.UNIT Display in °C or °F °C 0 0 °C

°F 1

12 *T.ADJ Calibrate temperature Adjust to allow for cable resistance None

13 *T.COMP Set temp comp Compensation for process changes off 0 0 Off

Compensation for process changes on 1

*T.COEF Adjust process TC Set for TC in pH per 10 °C -0.00 pH per

10 °C

14-19 Not used

IM 12B6C3-E-E

5-15 Parameter setting

5-3-3. Calibration functions

Code 20

t.SEC & These functions are used to determine the stability level demanded by the EXA as

pH acceptance criteria for the automatic calibration. The default settings give a good

calibration for general purpose electrode systems with a fast response. Where
heavy duty electrodes are used, or when low temperatures are concerned, these
values should be adjusted.

When adjusting these settings, the longer the time interval and the smaller the

pH change, the more stable will be the reading. However, it is important to bear
in mind that the time taken to reach stability is an exponential function, and too
ambitious a setting will cause the instrument to wait for a very long time before
accepting a calibration.

Code 21 AS.LOW & Limit values for the drift of an electrode system before an error is signalled when
AS.HI a calibration is done. These default values should be adjusted to suit the

application, this will be especially important with enamel or Antimony probes.
In case in SC 27 the Asymmetry Potential is disabled and the Zero Point is used,

SC 21 is used for entering the limits of the Zero Point.
ZR.LOW & Limit values for zeropoint, if enabled in Code 27.
ZR.HI

Code 22 SL.LOW & Limit values for acceptable slope (sensitivity) calibrations.
SL.HI

Code 23 ITP, SLOPE Values can be entered directly in this section. These data can be provided by the
& ASPOT manufacturer of the probe, or by the users laboratory etc. They are determined

independently of the measuring loop.

NOTE: it is not necessary to enter this data in most cases as the EXA

automatically does this while performing a calibration. The feature is used
in the case of special electrode systems and where calibration in the
process environment is not possible.

Code 24, Buffer tables The following buffer calibration tables are programmed into the EXA. They are the
25, & 26 primary buffer standards according to NIST (formerly NBS) and various other

national standards. We strongly recommend the use of these buffer solutions as

they give the best buffer capacity, reliability and accuracy when calibrating.

Table 5-1.

pH 4 pH 7 pH 9 pH 4 pH 7 pH 9

0 °C 4.00 6.98 9.46 45 °C 4.05 6.83 9.04
5 °C 4.00 6.95 9.40 50 °C 4.06 6.83 9.01
10 °C 4.00 6.92 9.33 55 °C 4.08 6.83 8.99
15 °C 4.00 6.90 9.28 60 °C 4.09 6.84 8.96
20 °C 4.00 6.88 9.23 65 °C 4.11 6.84 8.94
25 °C 4.01 6.87 9.18 70 °C 4.13 6.85 8.92
30 °C 4.02 6.85 9.14 75 °C 4.15 6.85 8.90
35 °C 4.02 6.84 9.10 80 °C 4.16 6.86 8.89
40 °C 4.04 6.84 9.07

These tables may be adjusted in the case that the user wishes to use other

calibration solutions. The “name” of the buffer can be changed at the *BUF.ID

prompt. The other values can then be adjusted in sequence.

Code 27 Zero Point As an alternative to Asymmetry Potential, the Zero point can be used to define

and calibrate the EXA pH unit.

Note that this method conforms to the DIN standard for instruments

No. IEC 746-2.

IM 12B6C3-E-E

Parameter setting 5-16

Code Display Function Function detai• X Y Z Default values

Calibration functions

20 *

t.SEC Stability check time 5 sec.

*PH Stability check pH 0.02 pH

21 *AS.LOW As Pot low limit -120 mV

(As Pot) *AS.HI As Pot high limit 120 mV

21 *ZR.LOW Zero Point low limit 5.00 pH

(Zero) *ZR.HI Zero Point high limit 9.00 pH

22 *SL.LOW Slope low limit 70 %

*SL.HI Slope high limit 110 %

23 *ITP Set ITP Preset calibration data from manufacturer 7.00 pH

(pH) *SLOPE Set slope or from laboratory determinations. 100 %

*ASP.1D Set As Pot For the main parameter 0.0 mV

Press YES to confirm 0.1 mV resolution,

then set value with >, ^, ENT keys.

Press NO to change to *ASP.

*ASP Set As Pot For the main parameter

Press YES to confirm 1 mV resolution,

then set value with >, ^, ENT keys.

*ASPmV Set As Pot ORP For parameter 2 (when activated in

service code 02)

23 *ASP.1D Set As Pot (ORP) For the main parameter

(ORP) Press YES to confirm 0.1 mV resolution,

then set value with >, ^, ENT keys.

Press NO to change to *ASP.

*ASP Set As Pot For the main parameter

Press YES to confirm 1 mV resolution,

then set value with >, ^, ENT keys.

24 *BUF.ID Buffer table 4 Buffer tables to NIST (formerly NBS)

25 *BUF.ID Buffer table 7 (see section 10 for table details)

26 *BUF.ID Buffer table 9 User adjustable for special requirements

27 *ZERO.P Enable zero point in Disable zero point (enable As Pot) 0 0 Disabled

pH units Enable zero point (disable As Pot) 1

28-29 Not used

pH

mV

ITP

As pot

0 mV

0 ºC

10 ºC

25 ºC

12B6B3-12

ASYMMETRY POTENTIAL

mV

500

0

- 200
14

pH

ITP

Zero Point

0

7

Fig. 5-1.

IM 12B6C3-E-E

5-17 Parameter setting

5-3-4. mA output functions

Code 31 OUTP.F When pH is set in code 1 as the main parameter, the output functions may

be set as follows:­ pH
pH (table)
Parameter 2 (ORP or rH as set in code 02)
When ORP is set in code 1 as the main parameter, the output functions

may be set to:
ORP
ORP (table)

Code 32 BURN Diagnostic error messages can signal a problem by sending the output

signals upscale or downscale (21 mA or 3.9 mA)*. This is called upscale or

downscale burnout, from the analogy with thermocouple failure signalling

of a burned-out or open circuit sensor. The pulse burnout setting gives a

21 mA signal for the first 30 seconds of an alarm condition. After the

“pulse” the signal returns to normal. This allows a latching alarm unit to

record the error. In the case of the EXA the diagnostics are extensive and

cover the whole range of possible sensor faults.

* Only when the HART communication is disabled the downscale output

signal is 3.6 mA. When HART communication is enabled the output signal

is 3.9 mA.

Code 35 TABLE The table function allows the configuration of an output curve by 21 steps
(intervals of 5%).
The following example shows how the table may be configured to linearise

the output with a mA curve.

Table 5-2.

4-20 mA 4-20 mA
0% 4.0 mA 50% 12.0 mA
5% 4.8 mA 55% 12.8 mA
10% 5.6 mA 60% 13.6 mA
15% 6.4 mA 65% 14.4 mA
20% 7.2 mA 70% 15.2 mA
25% 8.0 mA 75% 16.0 mA
30% 8.8 mA 80% 16.8 mA
35% 9.6 mA 85% 17.6 mA
40% 10.4 mA 90% 18.4 mA
45% 11.2 mA 95% 19.2 mA
100% 20.0 mA

mA

IM 12B6C3-E-E

Parameter setting 5-18

Code Display Function Function detai• X Y Z Default values

mA Outputs

30 Not used
31 *OUTP.F mA output functions pH 0 0
Code 01 set for pH pH (table) 1
Parameter 2 (with suitable sensor(s), 2
and when enabled in code 02)
32 *BURN Burn function No burnout 0 0 No Burn.
Burnout downscale 1
Burnout upscale 2
Pulse burnout 3
33, 34 Not used
35 *TABLE Output table for mA
*0% Linearisation table for mA1 in 5% steps.
*5% The measured value is set in the main
*10% display using the >, ^, ENT keys, for
... each of the 5% interval steps.
... Where a value is not known, that value may
*90% be skipped, and a linear interpolation will
*100% take place.
36-39 Not used

mA

IM 12B6C3-E-E

5-19 Parameter setting

5-3-5. User interface

Code 50 *RET. When Auto return is enabled, the converter reverts to the measuring mode from

anywhere in the configuration menus, when no button is pressed during the set
time interval of 10 minutes.

Code 51 *MODE The manual impedance check (on demand) can be setup for operation in the

maintenance mode. (Through the closed front cover).

Code 52 *PASS Passcodes can be set on any or all of the access levels, to restrict access to the

instrument configuration.

Code 53 *Err.4.1 Error message configuration. Two different types of failure mode can be set.

Hard fail gives a steady FAIL flag in the display, A Fail signal is transmitted on the

outputs when enabled in code 32.

Soft fail gives a flashing FAIL flag in the display. The call for maintenance is

a good example of where a SOFT fail is useful. A warning that the regular
maintenance is due, should not be used to shut down the whole measurement.

Code 54 Not used

Code 55 *CALL.M Call for maintenance is a trigger to signal that the system has been in service for

longer than the set time without calibration. The user can set up to 250 days as a
routine service interval.

Code 56 *DISP The display resolution can be set to either 0.01pH or 0.1pH. Not applicable to the

ORP (mV) display.

IM 12B6C3-E-E

Parameter setting 5-20

Code Display Function Function detai• X Y Z Default values

User interface

50 *RET Auto return Auto return to measuring mode Off 0
Auto return to measuring mode On 1 1 On
51 *MODE Mode setup Manual impedance check Off 0 0 Off
Manual impedance check On 1
52 *PASS Passcode Maintenance passcode Off 0 0.0.0 Off
Note # = 0 - 9, where Maintenance passcode On #
0 = no passcode Commissioning passcode Off 0 Off
1=111, 2=333, 3=777 Commissioning passcode On #
4=888, 5=123, 6=957 Service passcode Off 0 Off
7=331, 8=546, 9=847 Service passcode On #
53 *Err.4.1 Error setting Impedance low (input 1) Soft fai• 0
Impedance low (input 1) Hard fai• 1 1 Hard
*Err.5.1 Impedance high (input 1) Soft fai• 0
Impedance high (input 1) Hard fai• 1 1 Hard
*Err.4.2 Impedance low (input 2) Soft fai• 0
Impedance low (input 2) Hard fai• 1 1 Hard
*Err.5.2 Impedance high (input 2) Soft fai• 0
Impedance high (input 2) Hard fai• 1 1 Hard
*Err.07 Temperature too high Soft fai• 0
Temperature too high Hard fai• 1 1 Hard
*Err.08 Temperature too low Soft fai• 0
Temperature too low Hard fai• 1 1 Hard
*Err.09 pH out of range Soft fai• 0
pH out of range Hard fai• 1 1 Hard
*Err.11 Wash recovery check Soft fai• 0 0 Soft
Wash recovery check Hard fai• 1
*Err.16 Call for maintenance Soft fai• 0 0 Soft
Call for maintenance Hard fai• 1
54 Not used
55 *CALL.M Call for maintenance Set time limit for calibration Off 0 0 Off
Set time limit for calibration On 1
56 *DISP Display resolution Set pH decimal display 0.1 pH 0
Set pH decimal display 0.01pH 1 1 0.01 pH
57-59 Not used

IM 12B6C3-E-E

5-21 Parameter setting

5-3-6. Communication setup

Code 60 *COMM. The settings should be adjusted to suit the communicating device connected to

the output. The communication can be set to HART or to PH201

*

B distributor

(for Japanese market only)

*ADDR. For the Yokogawa PC202 software package, the default settings match the

software as shipped.

Code 61 *HOUR The clock/calendar for the logbook is set for current date and time as reference.
*MINUT
*SECND
*YEAR
*MONTH
*DAY

Code 62 *ERASE

Erase logbook function to clear the recorded data for a fresh start. This may be
desirable when re-commissioning an instrument that has been out of service for a
while.

5-3-7. General

Code 70 *LOAD The load defaults code allows the instrument to be returned to the default set up

with a single operation. This can be useful when wanting to change from one
application to another.

Code 79 *CUST.D Load customer defaults. This code allows the instrument to be returned to the
factory default set, except that buffer tables (code 24,25,26) are unchanged.

5-3-8. Test and setup mode

Code 80 *TEST The test mode is used to confirm the instrument setup. It is based on the factory

setup procedure and can be used to check the QIC (factory generated test
certificate). To use this test feature it is necessary to have the detail provided
only in the QIS (Quality Inspection Standard) or the Service manual.

NOTE: attempting to change data in service code, 80 and above without the proper instructions and

equipment, can result in corruption of the instrument setup, and will impair the performance of the unit.

mA

mA

IM 12B6C3-E-E

Parameter setting 5-22

Code Display Function Function detai• X Y Z Default values

Communication

60 *COMM. Communication Set communication Off 0 1.0 On
Set communication On 1
write enable 0 write
write protect 1 enable
Set communication PH201*B 2
Without half time check 0
With half time check 1
*ADDR. Network address Set address 00 to 15 00
61 *HOUR Clock setup Adjust to current date and time using
*MINUT >, ^ and ENT keys
*SECND
*YEAR
*MONTH
*DAY
62 *ERASE Erase logbook Press YES to clear logbook data
63-69 Not used

Code Display Function Function detai• X Y Z Default values

General

70 *LOAD Load defaults Reset configuration to default values
71-78 Not used
79 *CUST.D Load Customer Reset configuration to default values
Defaults except buffer tables

Code Display Function Function detai• X Y Z Default values

Test and setup mode

80 *TEST Test and setup Built in test functions as detailed in QIS
and Service Manual

mA

mA

IM 12B6C3-E-E

5-3-9. Notes for guidance in the use of service coded settings

5-23 Parameter setting

IM 12B6C3-E-E

Calibration 6-1

6. CALIBRATION

The EXA PH202 can be calibrated in three distinct ways.

6-1. Automatic calibration

This method uses internally programmed buffer tables, (from Service Codes 24, 25 and 26), to calculate
the buffer value at the actual temperature during the calibration. In addition, the stability of the reading
is automatically calculated, and when the reading has stabilized fully automatic adjustments of slope
and asymmetry are made. This eliminates the question of how long the operator should allow prior to
adjustment. A menu driven prompt system conducts the operator through the simple, foolproof routine.

Default settings for the buffer solutions are the standard NIST (formerly NBS) recognised solutions “4”,
“7” and “9”. These are known as primary buffers. They have a much better buffer capacity than the
“commercial” or adjusted buffers. Yokogawa strongly recommends the use of these buffers to provide the
best pH calibration.

6-2. Manual calibration

In this method, the operator decides on the actual value to enter. Manual calibration is most often used for
single-point adjustment of the asymmetry potential, by comparison method.

Manual calibration can also be used to perform a full 2-point calibration with solutions other than the NIST
buffers that are listed in the calibration tables. In this case, the solutions are applied sequentially as in the
AUT CAL method, but the user determines the adjustment of reading and stability.

NOTE:
During manual calibration the temperature coefficient is still active. This means that the readings are referred
to 25 °C. This makes grab sample calibration easy and accurate. However, if the manual calibration
technique is used for buffer calibration, the temperature coefficient must be set to zero in maintenance
mode in the “TEMP” routine (see chapter 5).

6-3. Sample calibration

The operator activates the “SAMPLE” calibration routine, at the same time as taking a representative
process sample. After determining the pH of this sample by independent methods, (in the lab for example)
the reading can be adjusted. While the sample is being analyzed, EXA holds the sample data in memory,
while continuing to control and read pH normally.

6-4. Data entry

In special circumstances, users can directly enter the calibration data in the service code menu (see chapter

5). This is appropriate where the manufacturer provides calibration data for each probe (as with the Pfaudler
sensors) or where electrodes are laboratory calibrated for subsequent installation on the plant.
Service Code 23 allows the values of ITP, asymmetry potential (or zero point) and slope to be entered.

IM 12B6C3-E-E

6-2 Calibration

pH

pH

YES NO

YES NO

YES

NO

pH

YES NO

pH

NO

pH

YES

Press YES for single point
(As Pot) adjustment

.

Press

NO to proceed to calibrate Slope.

The instruments waits for
the reading to stabilize

.

(The pH display flashes

)
When reading Is stable,
the CAL END messag

e

appears.

Transfer to second buffer (pH4) and press YES

.

After briefly displaying WAIT, the display

returns to the normal readout.

The display now flashes th

e
pH value. The instrument
waits for the reading to stabilize

.

NO

YES

pH

NO

YES

pH

YES

pH

ENT

MAN.CAL

DISPLA Y

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CAL

MEAS URE

12B6C3-30

NO

YES

pH

Automatic Calibration Press the MODE key. AUT.CAL appears in the display, and the

YES/N

O key prompt flags flash. Press YES.

NEW.SNS: Display flashes YES/N

O

answer YES if new sensor fitted or

NO if not.

Care! YES resets logbook calibration data.

Insert the sensors in pH 7 buffer solution

.

Press YES to start calibration

.

NO

Note: To start calibration with another solution, press NO to cycle through the other options.
"CAL 7"

NO "CAL 4" NO "CAL 9" NO

"CAL 7"

YES

When the reading is stable, the CAL END
message appears. Press YES

.

After briefly displaying WAIT, the display returns to
the normal readout

.

6-5. Calibration procedures

6-5-1. Automatic calibration

IM 12B6C3-E-E

Calibration 6-3

pH

HOLD

NO

YES

pH

YES

pH

HOLD

YES NO

pH

HOLD

pH

HOLD

HOLD

pH

NO

YES

12B6C3-31

NO

YES

pH

HOLD

pH

YES

NO

HOLD

pH

pH

HOLD

NO

YES

NO

YES

NO

YES

NO

YES

Automatic Calibration With Hold Active

Note: To start calibration with another solution, press NO to cycle through the other options.
"CAL 7"

NO "CAL 4" NO "CAL 9" NO

"CAL 7"

The single

­point
calibration
is now
complete.
put sensors
back in the
process an

d

press NO

to
switch off
HOLD and
return to
measuring
mode

.

Transfer to pH 4
buffer and press YES

.

The instrument then waits for the reading
to stabilise. (The pH display flashes).

When the reading is stable, the CAL EN

D

message appears. Press YES

.

WAIT flashes briefly then HOLD

The calibration is now complete. Put the sensors back in the process
and press

NO to turn off HOLD and return to the measuring mode.

NO

Press YES for single point
(As Pot) adjustment.
Press NO to proceed to calibrate Slope.

The instruments waits fo

r
the reading to stabilise.
(The pH display flashes

)
When reading Is stable,
the CAL END message
appears.

YES

Press the MODE key. AUT.CAL appears in the display, and the

YES/N

O key prompt flags flash. Press YES.

NEW.SNS: Display flashes YES/N

O

answer YES if new sensor fitted or NO if not.

Care! YES resets logbook calibration data.

Insert the sensors in pH 7 buffer solution.

Press YES

to start calibration.

pH

ENT

MAN.CAL
DISPLA

Y

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CA

L

MEAS URE

6-5-2. Automatic calibration with HOLD active

mA

IM 12B6C3-E-E

6-4 Calibration

pH

NO

YES

pH

NO

YES

YES

NO

YES

pH

YES

pH

pH

NO

YES

ENT

pH

pH

pH

pH

NO

YES

Put sensors in buffer
solution. Press YES

.

Set the value
using the

>, , ENT key.

Select the flashing digit with the

> key.

Increase its value by pressing th

e key.

When the correct value is displayed, press ENT to enter the change

.

>

>

12B6C3-32

pH

NO

YES

Manual Calibration. (2nd parameter calibration) Press the MODE key. The legend AUT.CAL appears,

and the YES/NO key prompt flags flash. Press NO

.

The display MAN.CAL appears.

Press YES to start calibration.

Press YES or NO at NEW.SNS prompt

.

YES

NO

For 2 point (As Pot and Slope)

Adjustment select second buf

fer

solution and adjust as for pH7 buf

fer.

NO

ENT

ENT

YES

WAIT is displayed
briefly then EXA returns
to measuring mode

.

pH

ENT

MAN.CAL
DISPLA

Y

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CA

L

MEAS URE

6-5-3. Manual calibration (2nd parameter calibration)

IM 12B6C3-E-E

Calibration 6-5

IM 12B6C3-E-E

6-6 Calibration

pH

NO

YES

NO

YES

pH

pH

pH

NO

YES

12B6C3-34

pH

NO

YES

Sample Calibration.

Press the MODE key. The legend AUT.CAL appears, and the YES/NO

key prompt flags flash. Press NO

.

The display MAN.CAL appears.

Press NO.SAMPLE appears

YES

Press to start calibration

.

NO

YES

NO

YES

Press YES at the same time as taking
sample for analysis.

PH 202 now continues to measure/control,
as before. SAMPLE flashes to indicate that
data is stored waiting for input of analyze

d

value.

pH

ENT

MAN.CAL
DISPLA

Y

HOLD

NO MODEYES

YOKOGAWA

MODE

TEMP

AUT.CA

L

MEAS URE

6-5-4. Sample calibration

IM 12B6C3-E-E

Calibration 6-7

pH

NO

YES

MAN.CAL

NO

YES

pH

MAN.CAL

YES

ENT

pH

MAN.CAL

pH

NO

YES

MAN.CAL

YES

pH

NO

YES

Set the value
using the

>, , ENT key.
Select the flashing digit with the > key.
Increase its value by pressing the

key.

When the correct value is displayed,
press EN

T to enter the change.

>

>

YES

pH

NO

YES

pH

MODE

NO

pH

When the laboratory analysis is completed
the data is entered by first pressing MODE,
then following the sequence belo

w

Note: Display show

s
the value as at the time
of taking the sample

.

ENT

Return to maintenance

menu

NO

NO

pH

NO

YES

YES

pH

NO

YES

pH

NO

YES

pH

NO

YES

YES

NO

NO

pH

NOYES

pH

YES

Note: Display shows

the value as at the time

of taking the sample.

NO

For first calibration
of a new sensor

YES

or

NO

or

To calibrate

ORP or rH

NO

YES

or

Return to maintenance
menu

IM 12B6C3-E-E

IM 12B6C3-E-E

Maintenance 7-1

7. MAINTENANCE

7-1. Periodic maintenance for the EXA transmitter

The transmitter requires very little periodic maintenance. The housing is sealed to IP65 (NEMA 4X)
standards, and remains closed in normal operation. Users are required only to make sure the front window
is kept clean in order to permit a clear view of the display and allow proper operation of the pushbuttons.
If the window becomes soiled, clean it using a soft damp cloth or soft tissue. To deal with more stubborn
stains, a neutral detergent may be used.

NOTE:
Never used harsh chemicals or solvents. In the event that the window becomes heavily stained or
scratched, refer to the parts list (Chapter 9) for replacement part numbers.

When you must open the front cover and/or glands, make sure that the seals are clean and correctly fitted
when the unit is reassembled in order to maintain the housing’s weatherproof integrity against water and
water vapor. The pH measurement uses high impedance sensors and may otherwise be prone to problems
caused by exposure of the circuitry to condensation.

The EXA analyzer contains a logbook feature which needs a clock to provide the timings. The EXA
instrument contains a lithium cell (battery) to support the clock function when the power is switched off. This
cell needs to be replaced at 5 yearly intervals (or when discharged). Contact your nearest Yokogawa service
centre for spare parts and instructions.

7-2. Periodic maintenance for the sensor system

NOTE:
Maintenance advice listed here is intentionally general in nature. Sensor maintenance is highly application
specific.

The sensor system must be kept clean to function well. This may require regular cleaning of the electrodes.
(The effect of dirty electrodes will be to slow the system response and perhaps corrupt the measuring loop
entirely). The frequency of cleaning and the method of cleaning will depend entirely on the process.

Where a refillable (flowing electrolyte) reference system is employed, make sure that the reservoir is kept
topped up. The rate of electrolyte consumption will again be process dependent, so experience will show
how often you must refill.

The periodic recalibration of the sensor system is necessary to ensure best accuracy. This takes into
account the aging of the sensors, and the nonrecoverable changes that take place. These processes are
slow, however. If frequent recalibration is needed, it is usually because the cleaning process is not effective,
the calibration is not well executed or the pH readings are temperature dependent. Monthly calibrations
should be sufficient for most applications.

If a film remains on the pH sensor after cleaning, or if the reference junction is partly plugged, then
measuring errors can be interpreted as a need for recalibration. Because these changes are reversible with
correct cleaning and/or proper selection or adjustment of the electrolyte flow through the junction, make
sure that these items are correct before recalibrating the system.

IM 12B6C3-E-E

7-2 maintenance

7-3. Calibration procedures are described in step-by-step detail in chapter 6. However, follow
these guidelines.

1. Before starting a calibration, make sure the electrode system is properly cleaned so that electrodes
are fully functional. They must then be rinsed with clean water to avoid contamination of the calibration
solution.

2. Always use fresh buffer solutions to avoid the possibility of introducing errors from contaminated or aged
solutions. Buffers supplied as liquids have a limited shelf life, especially alkaline buffers which absorb
CO2 from the air.

3. Yokogawa strongly recommends NIST (primary) buffer standards in order to ensure the best accuracy
and best buffer capacity is available. Commercially adjusted buffers (e.g. 7.00, 9.00 or 10.00pH) are a
compromise as a standard, and are often supplied without the temperature dependency curve. Their
stability will be much worse than for NIST solutions.

NOTE:
NIST (formerly NBS) buffers are available as consumable items from any Yokogawa sales office under the
following part numbers:
6C232 4.01 pH at 25°C}
6C237 6.87 pH at 25°C} A box contains 5 packets of powder. Each makes a 200 ml solution.
6C236 9.18 pH at 25°C}

IM 12B6C3-E-E

Troubleshooting 8-1

8. TROUBLESHOOTING

The EXA is a microprocessor-based analyzer that performs continuous self-diagnostics to verify that it
is working correctly. Error messages resulting from faults in the microprocessor systems itself are few.
Incorrect programming by the user can be corrected according to the limits set in the following text.

In addition, the EXA also checks the electrodes to establish whether they are still functioning within specified
limits. The transmitter checks the glass-electrode impedance for a low value to determine if it is broken or
cracked, and for a high impedance to check for internal breakage or disconnection.

The reference system is prone to more faults than the glass electrode in general. The unit measures the
impedance value and compares it to the programmed value in memory to determine acceptance during
testing. A high impedance signals pollution or poisoning of the reference electrode diaphragm.

Also, the EXA checks the electrodes during calibration to determine if the reaction time is suitable for pH
measurement. A specially timed check can be activated following each cleaning cycle. After calibration,
the unit checks the calculated asymmetry potential and the slope to determine if they are still within limits
specified by the software.

The slow shift of asymmetry potential could signal a poisoning of the reference electrode system by the
process. The decrease of slope equals a decrease of sensitivity of the glass electrode or can show a
coating buildup at the electrode.

The EXA makes a distinction among diagnostic findings. All errors are signaled by the FAIL flag in the
display. Only faults in the measuring circuit can be set as HARD FAIL, with “Burn-up or Burn-down” signals
on the mA output.

What follows is a brief outline of some of the EXA troubleshooting procedures, followed by a detailed table
of error codes with possible causes and remedies.

NOTE:
The diagnostic function of the EXA gives a variable time interval between impedance checks, up to 5
minutes. When trouble shooting, a manual impedance check can be initiated by following the procedure in
section 5-1-6.

IM 12B6C3-E-E

8-2 Troubleshooting

8-1. Diagnostics

8-1-1. Off-line calibration checks

The EXA transmitter incorporates a diagnostic check of the asymmetry potential after a calibration has been
completed. This is a valid check for both manual and automatic calibration routines.

The actual value can be called up from the DISPLAY routine in the maintenance menu. A large value
often indicates poisoning or pollution of the reference system used. If the asymmetry potential exceeds
programmable limits, the EXA generates an error (E2).

The EXA also performs diagnostics to check for the slope of the pH electrode after automatic calibration
is completed. The actual value of the slope can be called up on the DISPLAY routine in the maintenance
menu (SL). This value is an indication of the age of the electrode. If the value stays within the limits of 70 to
110 percent of the theoretical value (59.16 mV/pH at 25°C), it is accepted. Otherwise, the unit generates an
error (E3).

Activation or deactivation of the asymmetry diagnostic check and slope check is made from the Service
Codes. See Chapter 5 or Chapter 10 (Appendix).

8-1-2. On-line impedance checks

The EXA has a sophisticated impedance checking system. The sensors can be checked for their
impedance over a very wide range, which makes the tool equally useful for glass, enamel, reference and
metal (ORP) sensors. The measurement is temperature compensated for the characteristic of the pH glass
sensor.

In order to measure accurately over such a wide range, it is necessary to split the range into two. This is
done by a pair of jumper settings, high range and low range can be set on either input, making the system
extremely flexible.

The following error message table gives a list of problems that are indicated when the high or low
impedance limits are exceeded for a sensor. Such things as fouling, breakage and cable faults are readily
detected. The non-immersion of the sensors in the process fluid is also signalled.

IM 12B6C3-E-E

Troubleshooting 8-3

Table 8-1. Error Codes

Code Error description Possible cause Suggested remedy

E0 Buffer solution temperature Buffer solution too hot or too cold Adjust buffer temperature
outside the programmed range Check cabling
E1 Measurement failed to stabilize . Sensors fouled Clean sensors
during the calibration Sensors too slow (aged sensor) Replace sensors
E2 Asymmetry potential too high. Sensors are aged or polluted Check buffer solution
(Limits set in service code 22.) Mistake in calibration Recalibrate at pH7
Replace sensor
E3 Slope (sensitivity) is outside limits. Measuring sensor aged Replace measuring sensor
(Limits set in service code 23.) Poor insulation at the connector Replace or dry cables
E4.1 Impedance of input 1 too low. Measuring sensor broken Replace measuring sensor
(Limits set in service code 03.) Damaged or damp connections Replace or dry cable
E4.2 Impedance of input 2 too low. Reference sensor broken Replace reference sensor
(Limits set in service code 04.) Damaged connections Replace cables
E5.1 Impedance of input 1 too high. Measuring sensor disconnected Check connections
(Limits set in service code 03.) Sensors not immersed in process Check process
Liquid earth disconnected Check connections
E5.2 Impedance of input 2 too high. Reference sensor fouled Clean or replace sensor
(Limits set in service code 04.) Liquid earth disconnected Check sensor immersion
Insufficient electrolyte Check electrolyte reservoir
E7 Temperature sensor open Process too hot or too cold Check process
> 1400C (or <-100C for 8k55) Wrong temperature sensor setting Check sensor & setting
Temperature sensor damaged Check connections
E8 Temperature sensor shortened Process too cold or too hot Check process
< -30 0C (or > 120 0C for 8k55) Wrong temperature sensor used Check sensor & setting
Temperature sensor damaged Check connections
E9 Measurement out of range (-2 to 16 pH) Sensors disconnected Check cabling
Sensor wrongly connected Check cabling
Sensor(s) defective Replace sensor(s)
E10 EEPROM write failure Fault in electronics Try again, if unsuccessful
contact Yokogawa
E11 Wash recovery check error Measuring sensor aged Replace measuring sensor
(if communication is set to pH201*B in code Sensor still coated after washing Check cleaning system

60) Defective wash system If needed adjust timings
E12 ORP / rH outside of preset limits Sensors disconnected or wrongly Check cabling
connected
E14 No valid calibration data. Data lost after switching from Recalibrate
pH to ORP
E15 Cable resistance to temperature Cable resistance too high Use Pt1000
sensor exceeds limit value. Corroded contacts Clean and reterminate
Wrong sensor programmed Reprogram
E16 Call for maintenance interval time exceeded. System not maintained in Perform maintenance
preset time period Reset interval
E17 Output span too small < 1pH Incorrect configuration by user Reprogram
E18 Table values make no sense
E19 Programmed values outside acceptable limits Incorrect configuration by user Reprogram
E20 All programmed data lost Fault in electronics Contact Yokogawa
Very severe interference
E21 Checksum error Software problem Contact Yokogawa
E23 Zeropoint outside limits Sensors are aged or polluted Check buffer solution
Mistake in calibration Recalibrate at pH7
Replace sensor

mA
mA

mA

IM 12B6C3-E-E

9-1 Spareparts

9. SPARE PARTS

Table 9-1. Itemized parts list

Item No. Description Part no.

1 Cover assembly including window, gasket and fixing screws K1542JZ
2 Window K1542JN
3a Internal works assembly (general purpose) K1544DA
3b Internal works assembly (intrinsically safe) K1544DD
4 Digital (display) board K1544DH
5a Analog (input) board (general purpose) K1544PL
5b Analog (input) board (intrinsically safe) K1544PE
6 Ribbon cable K1544PH
7 Eeprom + latest software pH202 K1544BK
8 Lithium cell (battery) K1543AJ
9 Terminals (block of 3) K1544PF
10 Terminals (block of 5) K1544PG
11 Housing K1542JL
12 Gland set (one gland including seal and backing nut) K1500AU
13 HART

®

modem for communications to PC K1544WM

Options

/U Pipe and wall mounting hardware K1542KW
/H Hood for sun protection K1542KG
/SCT Stainless steel tag plate K1544ST

10

9

4

5a(b)

11

12

2

13

7

8

6

1

3a (b)

Fig. 9-1. Exploded view

IM 12B6C3-E-E

Appendix 10-1

10. APPENDIX

10-1. User setting table

FUNCTION SETTING DEFAULTS USER SETTINGS

Parameter specific functions

01 *PH.ORP 0 pH
02 *PRM2 0 Off
03 *Z1.CHK 1.1.1 High range, TC on
check on,
04 *Z2.CHK 0.0.1 Low range, TC off
check off no TC
05 *CAL.CK 1.1 AP on, Slope on

Temperature functions

10 *T.SENS 0 Pt1000
11 *T.UNIT 0 °C
12 *T.ADJ None
13 *T.COMP 0 Off
*T.COEF -0.00 pH/10°C

Calibration functions

20 *t.SEC 5 Sec
*pH 0.02 pH
21 *AP.LOW -120 mV
*AP.HI 120 mV
22 *SL.LOW 70 %
*SL.HI 110 %
23 *ITP 7.00 pH
*SLOPE 100.0 %
*ASP.1D 0.0 mV
*ASP.mV mV
24 *BUF.ID 4 NIST 4
25 *BUF.ID 7 NIST 7
26 *BUF.ID 9 NIST 9
27 *ZERO.P 0 disabled

mA outputs

31 *OUTP.F 0 pH (ORP)
32 *BURN 0 off
35 *TABLE 21 pt table see code 31

mA
mA
mA

IM 12B6C3-E-E

10-2 Appendix

FUNCTION SETTING DEFAULTS USER SETTINGS

User interface

50 *RET 1 on
51 *MODE 0 off
52 *PASS 0.0.0 all off
53 *Err.4.1 1 hard fail
*Err.5.1 1 hard fail
*Err.4.2 1 hard fail
*Err.5.2 1 hard fail
*Err.07 1 hard fail
*Err.08 1 hard fail
*Err.09 1 hard fail
*Err.11 0 soft fail
*Err.16 0 soft fail
55 *CALL.M 0 250 days
56 *DISP 1 0.01 pH

Communication

60 *COMM. 0.1 off/write prot.
*ADDR. 00 00
61 *HOUR
62 *ERASE

General

70 *LOAD
79 *CUST.D

Test and setup mode

80 *TEST

mA

mA

IM 12B6C3-E-E

Appendix 10-3

10-2. Configuration checklist for PH202G

Standard Configuration Options Reference for

change

Measured Variable(s)

primary inputs pH, ORP and Temp
pH range 0-14 pH any span within -2-16 pH “output”
pH range linearized disabled 21 point table codes 31& 35
ORP range -500 to 500 mV spans up to 3000 mV between “output”

-1500 to 1500mV
Temperature range -30-140°C
Temperature unit Celsius Fahrenheit code 11
mA Outputs
analog output 4- 20 mA for pH pH/ORP/(parameter 2) code 01, 02, 31
output linearization disabled pH/ORP codes 35
Communication
digital interface disabled HART 60
communication software externa• HHC or PC202 contact factory
variables on display pH/ORP and temp pH/ORP, parameter 2, mA output “display”
SL, AP, Z1, Z2 etc.
burn out disabled burn low (3.9)/ high (22) on mA output code 32
password protection disabled for maint/ comm./ serv leve• code 52
autoreturn return to measure in 10 min. enable or disable code 50
add. functions in MAINT disabled Impedance check start code 51
Diagnostics
impedance checking active enable or disable code 03 & 04
check on calibration data active enable or disable code 05
check on stability 0.02 pH per 5 s choose stability leve• code 20
display calibration log. enabled with logbook diagnostics setup codes 03, 04 & 05
Compatibility
pH or ORP glass sensor/metal electrode pH or ORP code 01
temperature sensor Pt 1000 Pt1000; Pt100, etc code 10
other sensors enamel sensors (Pfaudler) ITP & impedance check setup codes 23, 03 & 04
2nd parameter disabled pH & ORP/ pH &rH code 02
manual temp. comp. disabled disable or enable “temp”
Special Features
buffer table configuration NIST standard fully configurable codes 24, 25 & 26
temperature calibration none adjustment +/- 20 °C code 12
zero point calibration disabled disable or enable code 27
call for maintenance set time interval 1 - 250 days code 55
HOLD during maintenance hold last or hold fix “hold”
process temp. compensation disabled set temperature coefficient code 13
logbook disabled 2 x 50 events code 61, 62

mA
mA
mA
mA

IM 12B6C3-E-E

10-4 Appendix

10-3. Setup for sensor compatibility

10-3-1. General

The inputs of the EXA transmitter are freely programmable for ease of installation. Standard glass pH
electrodes, Ag/AgCl reference electrodes and Pt100 and Pt1000 temperature sensors need no special
programming. The EXA indicates a fault with a signal in the display field if there is a mismatch of sensors in
the connection.

10-3-2. Selection of measurement and reference electrode

The EXA PH202 is preprogrammed to accept industry standard glass electrodes and reference electrodes.
The unit initiates checks for asymmetry and slope during calibration. The on-line impedance checking
function has been upgraded in this most recent EXA release.

The EXA is universally compatible with all types of electrodes, such as enamel and antimony. In such
systems, however, the specific isothermal point of intersection (ITP), slope (pH/mV) and asymmetry potential
can be set for the type of electrode.

10-3-3. Selecting a temperature sensor

The EXA PH202 reaches its highest accuracy when used with the Pt1000 temperature sensor. This element
offers a 10-fold increase in resistance dependence over the Pt100 sensor. Choice of temperature sensor is
made in the Service Codes found in Chapter 5 of this manual.

• ITP

Most Yokogawa sensor systems use an Iso-thermal point (ITP) of pH7 and a zero point at pH7. This

is the default condition for which the transmitter is set. It is only necessary to consider this adjustment
when installing a system with a different ITP. Antimony systems and Pfaudler probes are good examples
of systems with different ITP values. Service code 23 is used. This also permits the setting of calibration
data for precalibrated sensors.

• Temperature sensor

The Pt 100 U RTD sensor is now becoming the most commonly used for temperature compensation.

The transmitter accepts inputs from several different temperature sensors to suit most sensor systems.
Service code 10-19 are used to set the temperature parameters and the process temperature
coefficient.

• Temperature calibration

For best accuracy, the temperature sensor should be calibrated to compensate for connection cable

errors. See Service code 12.

• pH Calibration

Traditionally, users select buffer solutions to suit the chosen output range. This is merely a continuation

of the days of analog instruments that used indicators driven by the mA output. With digital technology,
it is better to choose good buffer solutions and make an effective calibration than to use commercial
(adjusted) buffers which may have round number values, but are less effective buffers with lower buffer
capacity. It is for this reason that Yokogawa recommends that the NIST 4, 7 and 9 standard buffers
be used to calibrate solutions. The temperature responses of these are pre-programmed into Service
codes 24, 25, and 26 in the EXA PH202. Where other buffers are used with the semi-automatic
calibration function, their temperature response should be programmed into the relevant code.

IM 12B6C3-E-E

Appendix 10-5

10-4. Setup for other functions

• Current outputs

Transmission signals for the measured parameters and FAIL signals can be set up in service codes 30

to 39.

• Diagnostic Checks

Impedance checks, response time and stability checks are all included in the PH202. In order to get

the best performance from each of these features, the converter should be fine tuned according to
experience in the installation, and for the particular sensors selected. Service codes 3, 4, 5 & 20 all
contribute to the diagnostics. Please note that the default settings provide an excellent starting point
and provide most valuable information about the performance of the electrode system.

• Communications

The proprietary HART (FSK) communication link allows remote configuration and data retrieval through

the PC202 communication package. This is an excellent tool for the maintenance engineer, quality
engineer or plant manager. Service codes 60-69 are used to set up the communications.

• Logbook

In combination with the communications link, a “logbook” is available to keep an electronic record of

events such as error messages, calibrations and programmed data changes. By reference to this log,
users can easily evaluate diagnostic information to determine predictive maintenance schedules. For
example, by monitoring the deterioration in the slope of the pH sensor, it can be changed before a
failure (or process shutdown) occurs.

mA

mA

IM 12B6C3-E-E

10-6 Appendix

10-5. Set up for Pfaudler Type 18 sensor

The PH202 is intended to measure with all sorts of pH sensors, including the Pfaudler Type 18 sensor. The
Pfaudler design of dual membrane system uses two enamels of differing sensitivity. The first a pH sensitive
membrane, and the second one that responds to Na

+

and K+ and acts as a reference.

The analyzer has dual high impedance inputs which measure perfectly even with very high impedance
sensors. However, the impedance measuring system (diagnostics) needs to be set up for best performance.

10-5-1. General set up

1. Set impedance measuring hardware. This is done by the use of links on the terminals adjacent to
the input terminals. For the Pfaudler system, this means that the terminals should have the links
disconnected in order to set for HIGH/HIGH impedance measuring.

2. Set the impedance check in software. Use codes 03 & 04 to enable the measurement and set for high
impedance and configure appropriate limits.

Code 03 set to 1.0.1 Iow limit 1 Megaohm
high limit 1 Gigaohm
Code 04 set to 1.0.1 Iowlimit 1 Megaohm
high limit 1 Gigaohm

3. Set the temperature compensation sensor as 100 Ohm Platinum RTD with service code 10.

Code 10 set to 1 100 Ohms Pt.

The system will now respond properly to the Pfaudler type 18 sensor, and the other functions of the EXA
analyzer will need to be set in the normal way to suit the use to which the loop is being put. Output ranges,
control functions and alarms should all be set as described elsewhere in this manual.

10-5-2. Calibration set up

4. The alternative Zero point (calibration and display) according to IEC 746-2 may be enabled in service
code 27, and set in the MAN.CAL routine. A value of 10.5 pH is a good starting point for the Pfaudler 18
sensor.

5. Where lab test data are available for the sensor, service code 23 can be used to set values for ITP &
Slope (and As pot for parameter 2 when enabled).

(This method can be useful for the type 18 sensor, as it is not usual to perform regular calibrations on this
system as with normal sensors. This is because the system may well respond differently, to ordinary buffers,
than with the process solutions. The procedure is to determine the temperature response (ITP) and the
sensitivity (Slope) of the sensor, and enter these values in code 23.)

Because this is a rather complex procedure, it is recommended instead to use the default settings of ITP
= 7.00, and Slope = 100 %, and make a single point (MAN.CAL) calibration in the process at the working
temperature, and at the normal operating (control setpoint) pH. This ensures that the desired control point
will be measured accurately, even if there may be small deviations when there is a big deviation from the
setpoint. This of course has no effect on the accuracy of a control loop. The special construction of the
Pfaudler sensor ensures that there is practically no drift in the calibration. All that is necessary is to keep
the sensor membranes clean. This is best done by cleaning with low pressure steam, which restores the
original condition of the sensor, including the original calibration values.

IM 12B6C3-E-E

Appendix 10-7

Display resolution
Auto return
Man. impedanc

e

Passcode

Hold on/off
Hold type
Hold valu

e

Manual temp valu

e

Manual temp

on/off

Temp. comp.
Imp. chec

k

Imp. limits

Temp. comp
Imp. chec

k

Buffer 4 name
Buffer4 0º

C....80º C

Buffer 7 nam

e

Buffer7

0º C....80º C

Buffer9 nam

e

Buffer9

0º C....80º C

Maintenanc

e

Commissionin

g

Service

Process value
Second process value
Temperature
% of output range

More

Status

Hold

Temp.Man

Logbook1
Logbook2

Ta

g

Unit

Device info

Param. Specific

Temp. Spec

Calibration Spec

.

Output function

Exa user interf

.

Manufacturer
Distributor
Model
Meas. type etc.

etc.

Device setup

Primary value
Analog outpu

t

Lower rangeval

.

Upper rangeval

.

Review

Stable time
Stable pH

Zeropoint
Aspot low limi

t

Aspot high limi

t

Slope low limi

t

Slope high limi

t

Buffer 4

Buffer

7

Buffer

9

table 0%.....

table 100%

Error 4.1.... Error 16

Timer on/off
Reload valu

e

ON LINE MENU

Level 1 menu Level 2 menu Level 3 menu Level 4 menu Level 5 menu

Process variab.

Diag/Servic

e

Basic setup

Detailed Setu

p

Slope
Aspot
Aspot2
Imp1

Imp2

Date
Descriptor
Messag

e

Write protect

second

parameter

Impedance input1

Impedance input2

Calibration check Imp. limits
Temp sensor
Temp unit
Temp comp.
Temp coeff.

Stability

Aspo

t

Slop

e

ITP

Buffer

mA function
Burn function

Table

Error programmin

g

Maintenance timer

Display

Slope value

10-6. Device Description (DD) menu structure

The Device Description (DD) is available from Yokogawa or the HART foundation. An example is shown
below of the ON LINE menu structure. This manual makes no attempt to explain the operation of the Hand
Held Communicator (HHC). For detailed operating instructions, refer to the HHC user’s manual and the on­line help structure.

mA

IM 12B6C3-E-E

10-8 Appendix

10-7. Field Change Order

Software changes of the PH202

10-7-1. Changes made by software release 1.1

- The hardware and software of the PH202 has been modified in order to make the instrument suitable for

8 temperature sensors.

- Software version 1.0 supports only the PCB suitable for 5 temp sensors.

- Software version 1.1 is prepared to handle both versions of transmitters (the 5 and 8 temperature sensor

PCB’s). The new release will recognize (auto detection) which version is used.

10-7-2. Changes made by software release 1.2

- In order to operate the PH202 in combination with the model 275 Hand-Held Communicator (HHC) from
Fisher-Rosemount it is necessary that :

- the software of the PH202 is updated.

- the Model 275 is upgraded with the PH202-Device Description (DD).

- In case the instrument in programmed as pH device with second parameter rH-measurement enabled
(Service code 02), the instrument returned with an inverted rH value. This calculation is now corrected in
this software release.

- When MODE keypress during non-successful calibration (E0, E1, E2 ,E3), the error will be cleared
instead of leaving the (soft) error active.

- In case a Sample is taken, the sample can be viewed. In this Sample view menu, the 2nd process value
was the actual measured value instead of the wanted sample value. In this release, the sample value is
shown correctly.

10-7-3. Changes made by software release 1.3

- Sample calibration did not work correctly in case the Temperature Coefficient (T.C.) is other than zero. -

The change in pH due to this T.C. was incorrectly interpreted as a direct aspot change.

- In case the passcode check was enabled, and an incorrect passcode was entered, this caused to stop
functioning of the display and keyboard.

- Writing of instrument setting went wrong. Communication related update for handheld and PC202
operation. For PC202 operation with the PH202, this software version is necessary.

- In case manual temperature was enabled, any temperature error (E7, E8) was still displayed. the
temperature errors should be cleared automatically in the case of a manual temperature value.

10-7-4. Changes made by software release 1.4

- A problem with Automatic Test Equipment during manufacturing was solved.

10-7-5. Changes made by software release 1.5

- The rH calculation was incorrect. There was a sign-error in the calculation formula. Also a 304mV offset
voltage has been added in the calculation to make it right for a modern sensor. The rH calculation is
correct now for a pH-sensor with a buffer solution of pH 7 and an Ag/AgCl/KCl reference system . The
old calculation was based on a sensor with a buffer solution of pH 1 (with HCl reference system).

10-7-6. Changes made by software release 1.6

- Sensor check is switched OFF now during the start of CAL to prevent an unclear situation for the
customer.

- Temperature errors were not switched OFF during MANTEMP.

- During INIT sometimes characters were missing in the messageline.

- During QIS the ORP measurement stops at 1220 mV. This has been changed so ORP can be measured
up to 1500 mV. Also temperatures below -10 ºC were not shown correctly.

IM 12B6C3-E-E

Appendix 10-9

10-7-7. Changes made by software release 1.7

- Default * T.COEFF changed from 0.00 to -0.00.

- Error 5.1 occurs (instead of 4.1) if no sensor is connected.

- E12 can only occur if second process is ORP or rH.

10-7-8. Changes made by software release 1.8

- Communications with PH201

* B possible.

- Three new temperature sensors (DKK 350, 6K8 and NTC10K).

- Periodically unused errors are reset.

- Service 79 added for loading defaults excepts pH buffer tables.

- No longer PIN needed for communication and “logbook scrolling”.

10-7-9. Changes made by software release 1.9

- Enabling user to set Zero point limits in service code 21.

- mA table handling improved.

- Interpolation mA table improved.

- Communication with PH201

* B improved (WASH).

- High impedance limit raised to 2G (as described in IM).

10-7-10. Changes made by software release 2.0

- E20 is cleared after the programmed data was recovered.

10-7-11 Changes made by software release 3.0

- The maximum ORP span is set to 3000mV (was 2000mV)
Communication is default set to enabled / write enabled

10-7-12 Changes made by software release 3.3

- The

NTC10k

was replaced by the

PTC10k.

10-7-13 Changes made by software release 3.4

- Updated internal tester identification range

.

10-7-14 Changes made by software release 3.5

- Fixed rare HART communication failure

.

10-7-15 Changes made by software release 3.6

- Solve problem with E4.1 / E5.1 impedance errors after loading all parameters from DCS

- Burn low value set to 3.6 mA, only selectable if HART-Communication is disabled

- Prevent incidental reset of the unit while loading default settings

- Prevent incidental communication problems with MH-02 PC-HART modem

10-7-15 Changes made by software release 3.7

- Implementation of Burn low in combination with HART changed.

IM 12B6C3-E-E

11-1 Test Certificate

Test EXA Series

Certificate Model PH202

Transmitter for pH / ORP

1. Introduction

This inspection procedure applies to the model PH202 converter. There is a serial number, unique to

the instrument, which is stored in non-volatile memory. Each time the converter is powered up, the
serial number is shown in the display. An example is shown below, for details see the Users manual:

Unique Number

Line Number
ATE (automatic test equipment no.)
Month code
Year code

2. General Inspection

Final testing begins with a visual inspection of the unit to ensure that all the relevant parts are present

and correctly fitted.

3. Safety Test

The (-) minus and the external ground terminal of the housing are connected to a Voltage generator

(100 VDC). The measured impedance value should be over 9.5 M.

Terminal 12 and the external ground terminal of the housing are connected to a Voltage generator

(500 VAC RMS) for 1 minute. The leakage current should remain below 8 mA.

4.1 Accuracy Testing

Our automated testing facility checks the accuracy of the dual high inputs of the instrument using a

calibrated variable resistor (decade resistor box) to simulate sensor mV’s.

4.2 Accuracy Testing of all supported temperature elements

Our automated testing facility checks the input accuracy of the instrument using a calibrated variable

resistor (decade resistor box) to simulate the resistance of all temperature elements.

11. Test Certificate

025

F70.00

IM 12B6C3-E-E

Test Certificate 11-2

4.3 Overall accuracy test

This test can be performed by the end-user to check the overall accuracy of the instrument. The data

specified on the Test certificate are results of the overall accuracy test performed during production and
can be reproduced by performing similar tests with the following test equipment:

1. A variable resistor box 1 (resistor decade box) to simulate the temperate element. All tests are

performed simulating 25ºC (77 ºF).

1. A fixed resistor of 300

 to simulate the mA-output load.

2. A millivolt source ranging from -1500 to +1500 mV with an accuracy of 0.1%.

2. A stabilised voltage supply unit : nominal 24 Volt DC

3. A current meter for DC currents up to 25 mA, resolution 1uA, accuracy 0.1%

3. A multimeter capable of measuring megohm ranges to check insulation impedance.

4. Screened cable to connect the input signals.

5. Single core flexible cable for liquid earth connection.

Connect the PH202 as shown in Figure 1. Set box 1 to simulate 25 ºC (1097,3

 U for Pt1000)

Before starting the actual test, the PH202 and peripheral testing equipment has to be connected to the

power supply for at least 5 minutes, to assure the instrument is warmed up properly.

Figure 1. Connection diagram for the overall accuracy test

The tolerances specified relate to the performance of the PH202 with calibrated test equipment

under controlled test conditions (humidity, ambient temperature). Note that these accuracy’s are only
reproducible when performed with similar test equipment under similar test conditions. Under other
conditions, the accuracy and linearity of the test equipment will be different. The display may show
values, which differ as much as 1% from those measured under controlled conditions.

4.4 Accuracy test mA output circuit

Our automated testing facility checks the output accuracy of the instrument with simulated

mA-output values.

IM 12B6C3-E-E

11-3 Test Certificate

IM 12B6C3-E-E

Glossary

GLOSSARY

pH (-log [H+] ) This is a logarithmic function of the Hydrogen ion activity (concentration).

This provides a quick indication of the acidic or alkaline behavior of a dilute
solution. Normally measured on a scale of 0-14 pH where low numerical values
are acidic (0 is approximately 1 Normal acid) and high numbers are alkaline
(14 is approximately 1 Normal NaOH). The neutral point is pH 7.

Defined by Nernst in the following equation: E = Eo + RT/nF x Ln [H+]

E = measured potential
R = gas constant
T = absolute temperature
n = valence
F = Faraday number
Ln = Napierian logarithm
[H+] = activity of the Hydrogen ion
Eo = Reference potential

ORP Oxidation reduction potential is a measure of oxidizing power of a solution.

The greater the milliVolt value with a negative polarity, the greater the oxidizing
power. Reducing power is indicated by positive values of mV.

rH This is a composite value that indicates the oxidizing power of a solution

compensating for the influence of the acid or alkaline components.
The scale is 0-55 rH, where oxidizing solutions provide the highest readings.

Asymmetry potential This is the difference between the isothermal point of intersection and the zero point.

Slope This is the sensitivity of the pH electrode (mV/pH) usually expressed as a % of the

theoretical value (Nernst).

ITP This is the isothermal point of intersection. This is the value in pH at which the

temperature response of the system is at a null point. In other words, the point of
intersection of the temperature lines on a graph of millivolts vs pH. This point is
critical to the correct operation of the temperature compensation circuitry.

Zero point This is the value of pH at which the electrode combination yields 0 mV as an output.

pH

mV

ITP

As pot

0 mV

0 ºC

10 ºC

25 ºC

12B6B3-12

ASYMMETRY POTENTIAL

mV

500

0

- 200
14

pH

ITP

Zero Point

0

7

IM 12B6C3-E-E
Subject to change without notice

Printed in The Netherlands, 12-701 (A) I

Copyright ©

Y

OKOGAWA

YOKOGAWA EUROPE B.V.

Databankweg 20
3821 AL Amersfoort

The Netherlands
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Fax [phone]
E-mail: [e-mail]
www.yokogawa.com/eu

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Newnan GA 30265
United States

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YOKOGAWA ELECTRIC ASIA Pte. Ltd.

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Singapore 469270
Singapore

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Fax [phone]
E-mail: [e-mail]
www.yokogawa.com.sg

YOKOGAWA HEADQUARTERS

9-32, Nakacho 2-chome,
Musashinoshi
Tokyo 180
Japan

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E-mail: [e-mail]
www.yokogawa.com.jp

Yokogawa has an extensive sales and
distribution network.
Please refer to the European website
(www.yokogawa.com/eu) to contact your
nearest representative.