YOKOGAWA PH200 User manual

IM 12B6C2-E-H
6th edition
Instruction
Manual Model PH200
2-wire pH transmitter
YOKOGAWA

FAIL
HOLD
MEASURE
AUT.CAL
MAN.CAL
DISPLAY
TEMP.
YES NO
ENT
OUTPUT
SET HOLD
SERVICE
*
NO MODEYES
>
ENT>
MODE
TEMP.MAN
HOLD
pH
mV
FAIL
HOLD
MEASURE
AUT.CAL
MAN.CAL
DISPLAY
TEMP.
YES NO
ENT
OUTPUT
SET HOLD
SERVICE
*
NO MODEYES
>
ENT>
MODE
TEMP.MAN
HOLD
pH
mV
OUTPUT HOLD
FLAG
MEASURED
VALUE DISPLAY
MESSAGE DISPLAY
KEY PROMPT FLAGS
SELECTION KEYS
YES : Accept setting
NO : Change to new setting
ADJUSTMENT KEYS
>: Choose digit for adjustment
^: Adjust digit (to decrease pass
through zero)
ENT : Enter new value
NOTE: The first digit changes from 1, -1, - to blank
SELECT MODE
MEASURE/MAINTENANCE
Can be used to escape program at any
time
MANUAL TEMPERATURE
COMPENSATION FLAG FAIL FLAG MENU POINTER FLAGS
MENU FOR MAINTE-
NANCE FUNCTIONS
(see chapter 5)
MENU FOR COMMIS-
SIONING FUNCTIONS
(see chapter 4)
SELECT MODE
MEASURE/COMMISSIONING
IM 12B6C2-E-H

IM 12B6C2-H-H
CONTENTS
1. INTRODUCTION ..................................................................1
1-1. Application......................................................................1
1-2. Required components for pH measurement...................1
1-3. Identification ...................................................................1
2. TECHNICAL SPECIFICATIONS...........................................2
2-1. General specifications.....................................................2
2-2. Functional description.....................................................3
3. INSTALLATION AND WIRING .............................................4
3-1. Installation and dimensions.............................................4
3-1-1. Installation site ...................................................4
3-1-2. Mounting methods.............................................4
3-2. Wiring of sensors............................................................6
3-2-1. General precautions...........................................6
3-2-2. Additional precautions for installations in
hazardous areas ................................................6
3-2-3. Liquid earth........................................................6
3-2-4. Access to terminal and cable entry....................6
3-2-5. Connection diagram for sensors........................7
3-3. Wiring of power supply...................................................8
3-3-1. General precautions...........................................8
3-3-2. Additional precautions for installations in
hazardous areas ................................................8
3-3-3. Connection of the power supply........................8
3-3-4. Switching the instrument on...............................8
4. COMMISSIONING..............................................................11
4-1. Operations overview .....................................................11
4-2. Output range adjustment.....................OUTPUT...........12
4-3. Set up the HOLD function ...................SET HOLD........14
4-4. Sensor selection and diagnostics..................................16
4-4-1. Selection of measurement and reference
electrode..........................................................16
4-4-2. Selecting a temperature sensor .......................16
4-4-3. Off-line calibration checks................................16
4-4-4. On-line impedance chacks ..............................16
5. MAINTENANCE..................................................................17
5-1. Automatic calibration...........................AUT.CAL...........18
5-2. Manual calibration ...............................MAN.CAL .........20
5-3. Selecting a value to display .................DISPLAY...........22
5-4. Temperature compensation.................TEMP ...............24
5-5. Hold output function.....................................................26
6. TROUBLE SHOOTING.......................................................28
6-1. Introduction ..................................................................28
6-2. Error messages and explanation...................................29

IM 12B6C2-E-H
7. SERVICE MODE.................................................................30
7-1. Introduction.................................................................30
7-2. Access to service settings...........................................31
7-3. Temperature function...................................................32
7-4. Temperature sensors...................................................32
7-5. Sensor checking..........................................................33
7-6. Display resolution ........................................................34
7-7. Signalling of fail condition ............................................34
7-8. Stabilization check.......................................................34
7-9. Auto return..................................................................35
7-10.Buffer tables................................................................35
7-11.Temperature adjustment..............................................36
7-12. Manual adjustment of ITP, slope and
asymmetry potential....................................................36
7-13. Passwordprotection by three digit code......................37
7-14. Restore default settings ..............................................37
8. CLASSIFICATION...............................................................38
8-1. Cenelec........................................................................38
8-2. FM................................................................................39
9. CHANGE FROM PH TO ORP MEASUREMENT ..............40
9-1. How to change from pH measurement to
ORP measurement.......................................................40
9-2. Commissioning the transmitter .....................................40
9-3. Maintenance of the transmitter .....................................40
9-4. Special features............................................................40
9-5. Wiring diagram .............................................................41
9-6. Buffer values.................................................................41
APPENDIX A............................................................................42

IM 12B6C2-E-H
1-1. Application
The EXA PH200 transmitter is a 2-wire pH
instrument intended to be used in industrial
installations in the field. For easy maintenan-
ce and operation it should be located close
to the sensors. It is powered from a remote
low voltage DC power supply through the 2-
wire connection. The EXA PH200 is compa-
tible with most commercial available pH sen-
sors and fitting systems.
The instrument is available in two versions:
- A general purpose version for use in safe
areas.
- An intrinsically safe version for use in
hazardous areas. The instrument can then
be installed in Zone 1 with the sensors in
Zone 1 or Zone 0.
The micro-processor is used in this instru-
ment for continuous sensor diagnostics,
flexible on site commissioning and fine tu-
ning by advanced functions.
In general a pH loop can be set up for diffe-
rent purposes:
- To be part of a total process control sys-
tem
- To indicate dangerous limits of a process.
- To monitor product quality.
1-2. Required components for pH
measurement
1. A pH electrode and a reference electrode
or a combined pH-reference electrode.
2. A temperature sensor Pt100 (according
to IEC 751 or DIN) or Pt1000
3. A fitting for the above electrodes with
accessories
4. Signal cables with or without extension
boxes, etc.
5. The EXA PH200 2-wire transmitter with
mounting accessories for wall or pipe
mounting
6. A DC power supply (nominal 24 V DC)
with cabling and optional zener barriers
or an intrinsic safe power supply
7. Peripherals: e.g. strip-chart recorder,
panel indicator, PID-controller.
1-3. Identification
The instrument has an identification label,
which is fixed to the front plate.
This serves as a reference for the full model
code, power supply voltage and serial num-
ber. This label also carries authorised marks
to certify compliance with the current regula-
tory norms.
1
1. INTRODUCTION
MODEL
SERIAL NO.
SUPPLY

2-1. General specifications
A. Intrinsic safety
– BASEEFA : Certified by and meets the require-
ments of EEx [ia] ib IIC T4 of CENE-
LEC
Certificate nr. : 89C2379)
– FM : For IS CL1, DIV1, GP ABCD
T3B for TA-30 to 70 °C
T4 for TA-30 to 40 °C
Approval report: J.I. 1Y1A7.AX
– CSA : For Ex[ia] Class 1, Div. 1, Groups C
and D, T4A
Approval file: LR 102851-1
B. Indicating range :-1 to +15 pH.
C. Transmission signal : 4 - 20 mA DC; max. load 550 Ω
D. Transmission range : 0 - 14 pH.
User programmable to any range
with a minimum span of 1 unit.
E. Power supply
– Model PH200G : 17 - 40 V DC,
dependent on load
– Model PH200S : 17 - 31,5 V DC,
dependent on load
F. Climatic conditions
– Ambient temperature : -10 to +55 °C
– Storage temperature : -30 to +70 °C
– Relative humidity : 10 to 90%
– Weather protection : Rain and dust-tight IP65 (NEMA 4X)
G. Housing
– Material : Cast aluminium with chemical resi-
stant coating
– Window : Flexible poly-carbonate
– Colours : Moss green/off-white
– Cable glands : Polyamide
– Cable entries : Two
h ” glands
Hose connection optional
– Earth connection : For external ground
H. Mounting possibilities
– Surface mounting : Two M6 bolts, 9 mm length
– Wall/Pipe mounting : With optional mounting kit
– Sunlight protection : With optional hood
– Panel mounting : 154 x 172 octagonal with
30 mm corners (fixing with self-tap-
ping screws
I. Shipping details
– Dimensions : 162 x 178 x 115 mm
– Package : 225 x 225 x 220 mm
– Weight : ca. 2,5 kg
J. Safety and security
– Data protection : EEPROM memory
– Interference test : According IEC 801
– Power down : No affect, reset to measurement
2. TECHNICAL SPECIFICATIONS
IM 12B6C2-E-H
2

IM 12B6C2-E-H
2-2. Functional description
The EXA PH200 is a real time micro-control-
ler operated pH analysing system. It uses a
dedicated micro-controller with exclusively
developed software to control all functions
necessary in such a system. The input and
output functions are concentrated in the
analogue section of the instrument. Even
these functions are operated through special
interfaces designed to give a minimum of
interference problems to the digital func-
tions. The digital and logic functions are
designed to operate securely. The unique
FAIL-function can give a warning when the
micro-controller has found a fault in the
measuring loop. This is accomplished by
sending a discrete 22 mA signal on the out-
put. The micro-controller checks the working
of the analogue to digital input converter cir-
cuit and watches over the conversion to the
output signals. By using non-volatile memory
(EEPROM) for the essential in formation the
operating parameters are fixed in memory
without the need for a battery. The software
is designed with the user in mind. It uses a
simple step by step, question and answer
style to communicate with the operator by
giving messages on the second line of the
display and indicating which keys are to be
pressed in the display too.
The user-interface is limited to a basic set of
6 keys accessible through the flexible win-
dow cover. The keys are scanned conti-
nuously and actions are taken immediately.
An extensive system of checking va lues and
parameters is implemented in the software .
The 2-wire design gives maximum flexibility
of operation with other industrial instruments
and controlling systems. An intrinsically safe
version is available for hazardous areas. The
rugged housing is designed for outdoor use
(IP65). In addition it is shaped in a way that
indoor panel mounting is also possible. The
optional universal mounting kit includes
brackets for all mounting methods. The
commissioning of the instrument can be
performed on site or in advance. A three
level operating system keeps the approach
clear and distinguishes between every day
operation and maintenance against one time
operations like commissioning or fine-tuning.
All this makes the EXA PH200 operate like a
normal analogue transmitter with a number
of additional functions.
These extra functions are only possible by
using a micro-controller at the heart of the
system:
• Sensor checking durig measurement (1)
• Simplified calibration through a semi-
automatic sequence.
• Additional process temperature compen-
sation can be activated.
• Simple range adaptation making it a ver-
satile instrument.
• Wide selection of temperature sensors.
• A HOLD-function for the output.
• Three buffer tables can be programmed.
• Programmable isothermal point of inter-
section.
• Protection against unauthorized access
by a passcode.
(1) European patent No. 0241601
US patent No. 4777444
3

3. INSTALLATION AND WIRING
IM 12B6C2-E-H
3-1. Installation and dimensions
3-1-1. Installation site
As the transmitter is a rain-tight type it can
be installed outdoors as well as indoors. It
should, however, be installed as close as
possible to the sensors avoiding long cable
lengths between sensors and transmitter.
The certified version can be installed in
Zone 1.
Select an installation site where:
- mechanical vibrations and shocks are
negligible;
- no relay/power switches are in the direct
environment;
- the transmitter is not mounted in direct
sunlight and severe weather conditions;
- maintenance activities are possible (no
corrosive atmospheres).
The ambient temperature and humidity
should be within the limits of the specifica-
tions .
3-1-2. Mounting methods
The EXA PH200 transmitter has universal
mounting possibilities:
- panel mounting using selftapping screws
- surface mounting on a plate (by bolts
from the back)
- wall mounting on a bracket (e.g. thick
brick wall);
- pipe mounting using a bracket on a hori-
zontal or vertical pipe (maximum diame-
ter 50 mm).
4
Panel mounting Surface mounting
DimensionsCut-outs for panel mounting
2 x M6 (Screws)
Unit: mm (“)Unit: mm (“)
154 (6.06`) 162 (6.4)
180 (7)
77
115 (4.5)
30 1.2)
30 (1.18)
172(6.77)
2x ø4
min. 203 (8)
min. 229 (9)

IM 12B6C2-E-H
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Option /M: Universal wall/pipe mounting kit
Pipe mounting
(vertical) Pipe mounting
(horizontal)
2” Pipe 2” Pipe
Wall mounting
115
(4.53)
70 (2.75)
56 (2.2)
200
(7.87)
2x ø6.6
(0.26)
4x ø10
(0.4) 77 (3.03)

IM 12B6C2-E-H
3-2. Wiring of sensors
3-2-1. 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 connec-
ting 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 dis-
tance of the sensor cables (max. 10 m)
– the setup is kept flexible for easy inser-
tion and retraction of the sensors in the
fitting.
3-2-2. Additional precautions for instal-
lations in hazardous areas
Make sure that the total of capacitances and
inductances connected to the input termi-
nals of the EXA PH200 do not exceed the
limits given in the certificate.
This sets a limit to the cable and extensions
used.
– Grounding:
• If the sensors are mounted in a grounded
fitting, the external earth connection on
the left hand side of the transmitter must
be connected to "protective" earth.
•If the sensors are mounted in a fitting iso-
lated to ground, it is recommended (not
required) to connect the earth connection
on the left hand side of the transmitter to
"protective" earth.
– The intrinsic safe version of the EXA
PH200 instrument can be erected 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.
3-2-3. Liquid earth
In all circumstances, the sensor side of the
measuring loop must be grounded to the
measuring liquid. The EXA PH200 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.
3-2-4. Access to terminal and cable
entry
1. To access terminals remove the front
cover of the EXA PH200 by releasing the
4 captive screws.
2. Thread the sensor cables into the con-
nection 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 immer-
sion fitting through a protective plastic
tubing to the transmitter.
6