Yokogawa SC72 User Manual

User’s
Manual

Model SC72
Personal Conductivity Meter

IM 12D03D02-01E

IM 12D03D02-01E

3rd Edition

Preface

Before using the Model SC72 Personal Conductivity Meter, read this manual thoroughly.

For safe use of this meter, the meter and the instruction manual include the following
symbol marks.

Preface

WARNING

CAUTION

: Indicates that serious injury may result, if users fail to follow

instruction manual procedures.

: Indicates that minor injury to personnel, or serious damage to

the product, may result if users fail to follow procedures in the
instruction manual.

WARNING

Do NOT use this instrument where there is a possibility of electrical shock.
Do NOT touch any part of the electrode immediately after measuring very hot liquids —

otherwise, you may get burnt.

CAUTION

If the meter will not be used for an extended period of time, be sure to remove the
battery. Otherwise battery leakage may occur, and may cause damage to the meter or
cause erroneous meter operation.

The contents of this manual are subject to change without prior notice.
Yokogawa Electric Corporation assumes no liability for damage, defects, or loss of the

product caused by any of the following:

User error;
Inappropriate or out-of-specifications use of the product;
Use in an unsuitable environment;
Repair or modification of this or related products by persons other than Yokogawa-

authorized engineers.

IM 12D03D02-01E
3rd Edition: Aug. 2009 (YK)
All Rights Reserved, Copyright © 2004, Yokogawa Electric Corporation

1

Preface

Liquid crystal display (LCD) display characters

The numeric LCD display is used to mimic alphabetic characters, as shown below:

Alphabet

A

B

C

D

E

F

G

H

I

J

K

L

M

Display

Alphabet

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Display DisplayNumerals

0

1

2

3

4

5

6

7

8

9

All display elements shown ON

Note Regarding Panels Shown in this Manual:

Panels shown in this manual should be regarded as examples. Actual panel format may
vary depending on parameter settings and on type of connected sensor.

Showing all display elements lit

Display (gray represents flashing state)

F00.EPS

Flashing state: Lit state:

2

IM 12D03D02-01E

Warranty and Service

Yokogawa products and parts are guaranteed to be free from defects in workmanship and
materials under normal use and service for a period of (typically) 12 months from the
date of shipment from the manufacturer.

Individual sales units may offer different warranty periods, so the original purchase order
should be consulted for the conditions of sale. Damage caused by normal wear and tear,
inadequate maintenance, corrosion, or due to chemical processes, is excluded from this
warranty coverage.

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

Model code and serial number
Copy of original purchase order showing the date
Length of time used, and the measuring environment
Fault symptoms, and circumstances of failure
Statement whether service under warranty or out-of-warranty service is requested
Complete shipping and billing instructions for return of goods, plus the name and

phone number of a contact person who can be reached for further information

Goods that have been in contact with process fluids must be decontaminated / disinfected
before shipment, and a statement to this effect should be included. Safety data sheets for
all process components that the goods have exposed to should also be included.

Preface

IM 12D03D02-01E

3

Contents

CONTENTS

Preface...................................................................................................................... 1-1

1. Outline ................................................................................................................. 1-1

1.1 Features ......................................................................................................................... 1-1

1.2 Personal Conductivity Meter Specifications .................................................................. 1-2

1.3 When You Receive This Conductivity Meter................................................................. 1-3

1.4 Contents of Model SC72 Personal Conductivity Meter Package ................................. 1-4

1.5 Component Names and Functions ................................................................................ 1-5

1.6 Sensor Part Names and Functions ............................................................................... 1-6

1.7 Options (Available Separately) ...................................................................................... 1-8

1.8 Spare Parts .................................................................................................................... 1-8

2. Preparation.......................................................................................................... 2-1

2.1 Installing the Batteries ................................................................................................... 2-1

2.2 Connecting Sensor Cable.............................................................................................. 2-2

2.3 Setting Date and Time................................................................................................... 2-3

2.4 Setting Temperature Unit .............................................................................................. 2-4

2.5 Setting Cell Constant ..................................................................................................... 2-4

2.6 Setting Temperature Compensation Coefficient ........................................................... 2-6

3. Measurement ...................................................................................................... 3-1

3.1 Precautions .................................................................................................................... 3-1

3.2 Measurement Procedures ............................................................................................. 3-2

3.3 Measurement Panel....................................................................................................... 3-3

3.4 Saving Measured Value ................................................................................................ 3-3

4. Keyswitch Functions.......................................................................................... 4-1

4.1 Names and Functions of Keys ...................................................................................... 4-2

4.2 Liquid Crystal Display and Display Items ...................................................................... 4-4

4.3 Function Modes ............................................................................................................. 4-5

5. Handling of the SC72 Personal Conductivity Meter ........................................ 5-1

5.1 Tips to Maintain Meter Performance ............................................................................. 5-1

5.2 Washing the Electrode .................................................................................................. 5-2

5.3 Cleaning and Drying Connector .................................................................................... 5-3

5.4 Calibration with Standard Solution ................................................................................ 5-4

5.5 Storage and Maintenance ............................................................................................. 5-7

6. Troubleshooting ................................................................................................. 6-1

6.1 Causes of Abnormal Conductivity Display .................................................................... 6-1

6.2 Error Messages and Corrective Action ......................................................................... 6-2

6.3 Causes of Abnormal Measured Value .......................................................................... 6-4

6.4 Other conditions............................................................................................................. 6-4

7. Measuring Principles of this Instrument .......................................................... 7-1

7.1 What Is Conductivity? .................................................................................................... 7-1

7.2 Principles of Operation .................................................................................................. 7-2

7.3 Temperature Compensation and Finding Temperature Compensation Coefficient ..... 7-3

7.4 Wetted Part Materials of Sensors ................................................................................. 7-4

Appendix ..................................................................................................................... 1

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

4

IM 12D03D02-01E

1. Outline

The Model SC72 Personal Conductivity Meter is an accurate, portable, easy-to-use
conductivity meter. It includes not only self-diagnostic functions, to help ensure validity
of readings, but also data storage functions to allow users to check past data. The meter
is of waterproof construction so that it can safely be used outdoors on a rainy day, and
can also withstand being accidentally dropped into water.

1.1 Features

Water r esistant case

When this meter is used with its dedicated sensor, it meets the requirements of class IP67
“Degree of Protection to be Provided by Enclosures” in IEC 60529.

Wide measurement range, and convenient “Auto Range” function

Sensors are available to cover measurement ranges between 0 to 2.000 mS/cm and 0 to 2
S/cm. Auto-range functions automatically set the optimum measurement range, making
measurement easy.

Automatic temperature compensation

Automatic temperature compensation functions are provided for liquid measurement.
Conductivity referenced to 258C can be obtained in solutions with temperature
coefficients between 0.00 and 9.99%/8C. The temperature coefficients for NaCl solutions
are already stored in the meter.

Calendar and time functions

Internal time functions allow “one-touch checking” of measurement date and time.

Data storage function

Up to 300 conductivities and temperature measurements, and their measurement date and
time, can be saved. This function allows you to check past measurement data.

Automatic power off function

The meter will power off automatically if not operated during a preset time interval.
The time interval can be set in one-minute increments in the range 1 to 120 minutes to

meet your application requirements. This automatic power off function can also be
disabled, but it is wise to leave it enabled to conserve the batteries.

Simple alarm clock function

The meter can issue an alarm signal at a specified time. Even when meter power is
turned off, the internal clock can issue an alarm signal.

Internal self-diagnostic functions display messages when appropriate.
Bright easy-to view large LCD

Displays liquid conductivity, liquid temperature, temperature coefficient, date and time.

1. Outline

IM 12D03D02-01E

1-1

1. Outline

1.2 Personal Conductivity Meter Specifications

Applicable measurement range:

• Sensors for high purity water measurement (cell constant: 0.05 cm-1)
Conductivity: 0 to 2mS/cm, 0 to 20mS/cm, 0 to 200mS/cm, 0 to 40MV•cm
Temperature: 0 to 808C*

• For general-purpose sensors (cell constant: 5 cm-1)
Conductivity: 0 to 20mS/cm, 0 to 200mS/cm, 0 to 2mS/cm, 0 to 20mS/cm,

0 to 200mS/cm,

Temperature: 0 to 808C*

• For chemical-corrosion-resistant sensors (cell constant: 5 cm-1)
Conductivity: 0 to 20mS/cm, 0 to 200mS/cm, 0 to 2mS/cm, 0 to 20mS/cm,

0 to 200mS/cm

Temperature: 0 to 808C*

• Sensors for high-conductivity measurement (cell constant: 50 cm-1)
Conductivity: 0 to 2mS/cm, 0 to 20mS/cm, 0 to 200mS/cm, 0 to 2S/cm
Temperature: 0 to 808C*

Resolution: Conductivity: Least significant digit: 1 digit;

Temperature: 0.18C

Repeatability (Conductivity):

62% (65% for general-purpose sensor on 0 to 200mS/cm measurement range)

Accuracy (Temperature): 60.78C (in the range 0 to 708C)

618C (when exceeding 708C)

Temperature compensation range:

variable 0.00 to 9.99%/8C, also (preset) NaCl solution temperature coefficient
Measurement converted to conductivity at standard temperature of 258C

Measured liquid temperature: 0 to 808C (0 to 508C when the sensor cable is immersed in

Ambient temperature:0 to 508C
Construction: IEC 60529, IP67 class of protection from environment
Power requirement: Two of size AA batteries (LR6)
Automatic power off interval: May be set in range 1 to 120 minutes
Battery life: About 200 hours of continuous use, for long-life alkaline battery (life

may vary depending on battery type and ambient conditions)

External dimensions: Approximately 150 (H) x 61 (W) x 42 (D) mm (not including

protruding portions)

Weight: Approximately 220 g (including batteries)

1

1

1

1

water)

1-2

*1: Display range is from -10 to 1208C.

IM 12D03D02-01E

EMC Compliance:
EMI (Emission): EN 61326-1 Class B

Test Item

Electromagnetic radiation disturbance

Frequency Range

30 to 1000 MHz

CISPR 16-1 and 16-2

EMS (Immunity): EN 61326-1 Table 2 (For industrial locations)

Test ItemNo.

Electrostatic

1

discharge

RF amplitude

2

modulated
electromagnetic field

* A: Normal performance within the specification limits: ±20% of the measured value.
B: Temporary degration or less of function or performance which is self-recoverable.
** Display value may be affected by strong electromagnetic field.

Test Specification Basic Standard

4 kV (contact)
8 kV (air)

80 to 1000 MHz,
10 V/m (unmodulated)
80% AM (1 kHz)

1.4 to 2.0 GHz,
10 V/m (unmodulated)

80% AM (1 kHz)

2.0 to 4.0 GHz,

3 V/m (unmodulated)
80% AM (1 kHz)

IEC 61000-4-2

IEC 61000-4-3

1.3 When You Receive This Conductivity Meter

Confirm that all SC72 meter package components (refer to Contents of Model SC72
Personal Conductivity Meter Package in Section 1.4 and sensor models described in Sec.

1.6, “Sensor Part Names and Functions.”) have been received. Carefully inspect the

meter and sensor, referring to Section 1.5, “Component Names and Functions” when
assembling meter and sensor.

Particular attention should be taken:

* Not to twist or force the cable.
* Not to hit or drop the meter.
* Not to get the sensor connector dirty.

1. Outline

Basic Standard

T0101.EPS

Performance

Criteria*

A

B**

A

A

T0102.EPS

IM 12D03D02-01E

1-3

1. Outline

1.4 Contents of Model SC72 Personal Conductivity Meter Package

Quick Manual

SC72 - - - AA

User's

Manual

1

3

2

4

Instrument Card

6

5

1-4

7

11 11 11 11

SC72 - 11 - - AA SC72 - 31 - - AA

*1 *1 *1 *1

Model Suffix code
SC72

Sensors -00

-11

-21

-23

-31

-41

Label -J
language - E

- -AA

*1 The meter model number and cell constants, as well as the sensor model no. (SC72SN-u-AA), are
shown on the nameplate.

8

SC72 - 21 - - AA
SC72 - 23 - - AA

Specification

Personal conductivity meter
Meter only, without sensor
With sensor for high purity water measurement
(cable length: 0.75m)
With general-purpose sensor
(cable length: 0.75m)
With general-purpose sensor (cable length: 3m)
With chemical-resistant sensor
(cable length: 0.75m)
With sensor for high-conductiivity measurement
(cable length: 0.75m)
Japanese
English
Always -AA

9

SC72 - 41 - - AA

Name

No.

Personal conductivity meter

1

Two dry batteries

2

Two i nstruction manual

3

Non-slip pads (two)

4

Hand strap

5

Instrument card

6

Sensor for high purity water

7

measurement
General-purpose sensor

8

Chemical-resistant sensor

9

Sensor for high-conductivity

10

measurement
Sensor cleaner

11

(five cotton swabs)

10

F010401.EPS

IM 12D03D02-01E

1.5 Component Names and Functions

1. Outline

O-ring

Sensor cable connector

Used to connect a dedicated
conductivity sensor to the

personal conductivity meter.

Can attach hand strap here

Display

Displays conductivity,

temperature, and
temperature coefficient
simultaneously.

Key switches

PERSONAL
SC METER

MODEL
STYLE
No.

E000001

2004.

Battery box cover fixing screw

SC72
S1.0

Instrument name plate

with model number
and serial number

F010501.EPS

IM 12D03D02-01E

1-5

1. Outline

1.6 Sensor Part Names and Functions

Four types of sensors are available for use with the Model SC72 Personal Conductivity
Meter:

(1) sensor for high purity water measurement (cell constant 0.05 cm-1),
(2) general-purpose sensor (cell constant 5 cm-1),
(3) chemical-resistant sensor (cell constant 50 cm-1), and
(4) sensor for high-conductivity measurement (cell constant 50 cm-1). Check the model

number and cell constant on the name plate to confirm which type of sensor you
have.

Model number and cell constants display plate example

MODEL

SC72SN

SUFFIX NO.

SC72SN Conductivity sensors for personal conductivity meter

Specification

SC72SN

-11

-19

-21

-23

-29

-31

-39

-41

-49

-AA

1: Part number of SC82 (previous model).

*
*2: Waterproofing is not guaranteed if you use SC82-type conductivity sensor in conjunction

with SC72 meter.

Conductivity sensor for personal conductivity meter
For SC72; for high purity water measurement (cable
length: 0.75m)
For SC82; for high purity water measurement (cable
length: 0.75m)
For SC72; for general purpose type (cable length: 0.75m)
For SC72; for general purpose type (cable length: 3m)
For SC82; for general purpose type (cable length: 0.75m)
For SC72; for chemical-resistant type (cable length:

0.75m)
For SC82; for chemical-resistant type (cable length:

0.75m)

*

For SC72; for high conductivity measurement (cable
length: 0.75m)
For SC82; for high conductivity measurement (cable
length: 0.75m)
Always -AA

CELL
CONST

Made in Japan

2

*

2

2

*

S1.0000001-11-AA STYLE

Cell constants

RemarksModel Suffix code

K9221XB

2

*

K9221XA

K9221XC

K9221XD

F010601.EPS

1

*

1-6

IM 12D03D02-01E

Sensor for high purity water measurement

SC72 - 11 - - AA

Model number and

cell constants display plate

Watertight cover

Prevents moisture
from entering

connector and causing
leakage between pins.

Connector

Connects sensor cable to

conductivity meter

Outer electrode

connection

(SUS316

stainless seel)

Inner electrode

(SUS316

stainless seel)

(SC72SN-11-AA)

*1

Sensor body

Outer electrode
(SUS316 stainless seel)

*1

Sensor

cable

Sensor grip

Plastic body can

withstand temperatures
up to 808C.

General-purpose sensor

Model number and

cell constants display plate

SC72SN-23-AA)

Watertight

cover

Connector

*1(SC72SN-21-AA,

Sensor body

Cover (Plastic)

SC72 - 21 - - AA
SC72 - 23 - - AA

Inner electrode
(Titanium)

Edge electrode
(Titanium)

1. Outline

*1

Sensor cable

Sensor grip

F010602.EPS

Chemical-resistant sensor

Model number and

cell constants display plate

Watertight

cover

*1(SC72SN-31-AA)

SC72 - 31 - - AA

*1

Sensor

cable

Sensor for high-conductivity measurement

SC72 - 41 - - AA

Model number and

cell constants display plate

Watertight

cover

Connector

*1(SC72SN-41-AA)

Connector

Air vent

Sensor body (glass)

Inner electrode
(platinum black)

Sensor grip

Air vent

*1 SC72SN-u will be described on sensor's name plate for the model number.

*1

Sensor grip

Sensor body (glass)

Inner electrode
(platinum black)

Sensor cable

F010603.EPS

IM 12D03D02-01E

1-7

1. Outline

1.7 Options (Available Separately)

The following options are available for the Personal Conductivity Meter for your
convenience. When ordering, specify part number shown below.

Standard solution

(Part no.: K9221ZA)

0.1mol/l NaCl solution for
calibration (250ml)

This soft black carrying case holds
conductivity meter and sensor.

Soft case

(Part no.: B9269KJ)

Approx. 280

Approx. 140

(Part no.: K9220XN)

Unit: mm

Approx. 30

This stand holds the sensor when
the conductivity meter is used on a
table. It is made of rustproof
stailess steel.

1.8 Spare Parts

O-rings and gaskets are important parts to ensure that the SC72 meter is water resistant.
Replace these parts as required. Refer to Section 5.5, “Storage and Maintenance” for
replacement.

O-ring and gasket set

(Part no.: K9654AY)

Sensor stand

F010701.EPS

1-8

Two battery box gaskets
Two sensor connection O-rings

F010801.EPS

IM 12D03D02-01E

2. Preparation

2.1 Installing the Batteries

Install the batteries first.

CAUTION

Select a relatively moisture-free location when installing batteries in the meter.
When installing batteries, observe correct polarity (battery orientation). Failure to do so

may damage to the meter.
Remove batteries from the meter if it is to be stored for an extended period of time.
Do not leave dead batteries in the meter. They may leak and cause meter failure or

erratic operation of the meter.
When replacing batteries, replace both batteries at the same time. If only one battery is

replaced, the new battery may discharge into the old battery, which may leak chemicals
and damage the meter.

If the battery box gasket is damaged or dirty then the unit may no longer be waterproof;
replace the gasket in this case.

(1) Loosen the screw holding the battery

box cover using a coin or similar
object.

(2) Remove the battery box cover, and

then install the batteries observing
polarity diagram inside.

(3) Make sure the gasket on the inside

458 or more

Batteries

Gasket

Press with
your fingers

rim of the battery box is free of
foreign material.

(4) Put the cover back on. Insert the tabs

on the top of the cover into the slots
at an angle of at least 458 and lower
the cover into position.

(5) Press the both ends of the cover down

with your fingers and tighten the
screw to fix the cover onto the unit
using a coin or similar object.

Note: Do not attempt to tighten further

when you feel resistance before the
cover is fastened in place. Loosen
the screw once and retighten.

2. Preparation

F020101.eps

IM 12D03D02-01E

2-1

2. Preparation

2.2 Connecting Sensor Cable

Connect the sensor cable as shown below.

CAUTION

Select a relatively moisture-free location when connecting the sensor cable.
When connecting the sensor cable, tighten by turning only the silver locknut, do not turn

the cable or waterproof cover. Also take care not wet or contaminate the connector.
Model SC82 sensors can be connected, but these are not guaranteed to be waterproof

when used with this meter.

(1) Pull the waterproof cover along the

sensor cable away from the
connector to expose the locknut.

(2) Connect the connector to the meter

body*. Then tighten firmly by
turning only the locknut.

* Align the slots of the sensor cable

connector with the posts of the
connector on the meter.

(3) Move the waterproof cover toward

the connector until it contacts with
the O-ring* on the meter body.

* Make sure that the O-ring is free of

foreign material.

(4) Push and rotate the waterproof cover

1/4 turn (90 degrees) clockwise to
lock into place.

(2)

Waterproof cover

O-ring

(3)

Locknut
(Silver)

(1)

(4)

F020201.eps

Caution: It is recommended that, as far as possible, you leave the sensor connected to the

meter to help ensure that the connector does not get dirty.

2-2

IM 12D03D02-01E

2.3 Setting Date and Time

After installing the batteries, set the date and time. Note that if the power is turned off
before setting “minutes,” start with the date setting when you turn on the power next
time.

If you replace the batteries, the date is not affected, but the time is reset. Reenter the
time.

Caution: If the sensor is not connected then an error will be displayed on the meter.

• Setting method

After installing batteries, press and hold the
all display elements turn on and the date setting display automatically appears. Set year,

month, day, hours, and minutes as follows:
Caution: If you stop part way through the date and time setting then the meter will beep

and the date and time will not be updated.

After

POWER

pressing

key for at least 1 sec.

POWER

key for at least one second. Then

2. Preparation

Year setting

After
several
seconds

F/ENT

F/ENT

to confirm

to confirm

to set

Day setting Hour setting (24-hour format)

to set

F/ENT F/ENT

to confirm

to set

After
several
seconds

Month setting

to set

F/ENT

to confirm

Minute setting

to set

to confirm

or

F020301.EPS

IM 12D03D02-01E

2-3

2. Preparation

2.4 Setting Temperature Unit

Default temperature units are 8C. To change to 8F, refer to Sec. 4.3 (13) Set temperature
units (tP.U) panel.

2.5 Setting Cell Constant

Even for sensors of the same type, each sensor has its own distinct cell constant. So, set
the proper cell constant as indicated on the sensor cable.

Whenever sensors are replaced, be sure to change the cell constant setting in the meter
accordingly. Cell constants once set are stored in non-volatile memory and are not lost
even when the batteries are replaced.

• Setting cell constants

Press the

Refer to Sec. 4.3 (4).

F/ENT

key to switch to function mode. Then select the C.C display with the
key and access the cell constant setting display with the
key to set the cell constant, then press the

F/ENT

key to confirm it.

F/ENT

key. Use the

2-4

IM 12D03D02-01E

F/ENT

for Function mode

select C.C

for C.C panel

F/ENT

to enter C.C

F/ENT

2. Preparation

MEAS

You can abort this procedure at any time by pressing
mode.

IM 12D03D02-01E

F020501.EPS

MEAS

to revert to measurement

2-5

2. Preparation

2.6 Setting Temperature Compensation Coefficient

As described in Section 7.3, liquid conductivity varies with liquid temperature.
Therefore, if concentration is measured by conductivity, the conductivity must be
converted to equivalent conductivity at a certain temperature. This instrument
incorporates standard temperature conversion functions to convert liquid conductivity
measurements to equivalent conductivity at 258C. To display equivalent liquid
conductivity at 258C, set the temperature compensation coefficient as described in this
section.

Temperature coefficient for NaCl solutions is stored in this instrument. If any other
solution is used, set the temperature compensation coefficient manually.

Refer to Sec. 4.3 (2) Temperature compensation setting (t.Co) panel.

2-6

IM 12D03D02-01E

• Set the temperature compensation coefficient

F/ENT

for Function mode

select t.Co

for t.Co panel

F/ENT

For NaCl solutions Manual setting

select NaCl or
%/8C (%/8F)

2. Preparation

F/ENT

MEAS

IM 12D03D02-01E

F/ENT

Set the temperature
compensation coefficient
with the keys.

F/ENT

MEAS

The temperature coefficient you set is displayed here

F020601.EPS

2-7

2. Preparation

2-8

IM 12D03D02-01E

3. Measurement

3.1 Precautions

(1) Be sure to check that the cell constant and the temperature coefficient are set

correctly.

(2) Check that the plastic cover (for general-purpose sensor) and outer electrode (for

high purity water measurement) are secure.

(3) Do not use the SC72 meter to measure liquids with temperatures over 808C. (If the

sensor grip is immersed, liquid temperature shall be below 508C.) Do not use the
meter to measure extremely corrosive liquids such as solutions of hydrofluoric
acid.

(4) Remove dirt and stains from the meter with soft tissue. If necessary, wipe the

meter case with neutral detergent.

(5) If any problem with the meter arises during measurement, refer to the

Troubleshooting section later in this manual to determine the cause.

(6) After finishing measurement, flush stains on the sensor and measured solutions

with water, and store the meter (refer to Chapter 5, “Handling of the SC72
Personal Conductivity Meter”).

When the meter is used on a table:

The meter is designed as a portable instrument; however, to use it on a table, attach non­slip pads (supplied with the instrument) at top and bottom of the meter to stop it from
moving when the sensor is moved.

3. Measurement

IM 12D03D02-01E

Non-slip pads

PERSONAL
SC METER

MODEL

SC72

STYLE

S1.0

No.

E000001

2004.

F0301.EPS

Figure 3.1 Position of Non-slip Seats

3-1

3. Measurement

3.2 Measurement Procedures

Dipping sensor into liquid

To help avoid errors due to air bubbles around the sensor element (inner electrode),
immerse the sensor into the liquid to be measured so that its air vent is below liquid
level. To dislodge any air bubbles from the inner electrode, dip the sensor into the liquid
and move it up and down two or three times.

Air vent

Measuring liquid level

Cover

Electrode
element

Figure 3.2 Dipping Sensor in Liquid (for general-purpose sensors)

If air bubbles are on this section,
measurement error may occur.

F0302.EPS

3-2

IM 12D03D02-01E

3.3 Measurement Panel

Immerse the sensor into the liquid to be measured to display the liquid conductivity on
the LCD display.

There are three measurement panel display types: the standard display, calendar, and
clock display.

MEAS

Use the

key to toggle the display type.

Standard display Calendar display Clock display

conductivity

MEAS MEAS

3. Measurement

temperature

T emperature

compensation coefficient

This display appears when NaCl

solution is specified at temperature
compensation coefficient setting.

day month yearMeasuring liquid

MEAS

3.4 Saving Measured Value

The meter offers two ways of storing measured values: HOLD for temporary storage and
non-volatile data storage that retains data even if batteries are removed.

(1) HOLD

If the
held (display no longer changes).

Press the

key is pressed during measurement, the measured values are temporarily

HOLD

MEAS

HOLD

key or

key to return to the measurement mode.

HOLD

HOLD

MEAS

or

F030401.EPS

hour : minute

F030301.EPS

IM 12D03D02-01E

3-3

3. Measurement

(2) Data storage

DATA

If the

F/ENT

key is pressed during measurement, mark starts flashing. Press the

key, then currently measured data can be stored in nonvolatile memory. Data

stored are measured conductivity, measured temperature, date and time. Up to 300 data
including individually deleted data can be stored. If you attempt to store more data,

is displayed.

If is displayed even though the number of data stored is less than 300, perform
“defrag” [refer to Section 4.3 (15), “Defragment storaged data (DFLG) panel”]. By doing

so, you can increase the number of data to be stored.
To check stored past data, refer to 4.3 (1) dAt (display stored measurement value) later

in this manual.

While is flashing, press the
mode without storing data.

While is flashing, press
or keys to abort data storage.

MEAS

Execute data storage.

Press key to store data while is flashing.

F/ENT

MEAS

key or

DATA

DATA

Abort data storage.

key to return to measurement

DATA

F030402.EPS

3-4

IM 12D03D02-01E

4. Keyswitch Functions

There are seven membrane keys on the keyboard of the Personal Conductivity meter.
The following key functions are provided.

* Display the conductivity, measured temperature and temperature coefficient.
* Display the conductivity, date and time.
* Hold conductivity and temperature measurements.
* Store conductivity and temperature measured data.
* Other functions such as parameter setting.

When meter is OFF, press for at
least 1 sec. to turn on power.
When meter is ON, press for
about 2 sec. to turn off the power.
Automatic Power OFF function
default: 20 min. inactivity.

If you press this key during
measurement, mark is
displayed, and present measured
values are held. To cancel, press

HOLD

or keys.

MEAS

If pressed during measurement,
mark flashes.

F/ENT

Press key to store measured
values in memory.
To abort data storage and return to

MEAS

MEAS mode, press or key

DATA

again while mark is flashing.

Auto Power Off

POWER

MEAS

HOLD

F/ENT

DATA

4. Keyswitch Functions

Press to start
measurement mode.
If already in MEAS
mode, it switches the
display panel.

If pressed while in

MEAS mode, switches

to function mode. Also

used to enter set

value.

Change set value.

F040001.EPS

IM 12D03D02-01E

4-1

4. Keyswitch Functions

4.1 Names and Functions of Keys

POWER

: Power ON/OFF key

If nothing is displayed on the LCD, hold down this key for about one second or more to
turn the power on.

If something is displayed on the LCD, pressing and holding this key for about two
seconds turns power off. If no keys are pressed during a certain time interval, power
turns off automatically (refer to “A.oFF,” Set Auto Power Off Interval of Section 4.3
(10)).

Press the

: HOLD key

key to hold the currently-displayed conductivity and temperature

HOLD

HOLD

measurement values ( mark turns on).
Press the

HOLD

key or

MEAS

key again to return to measurement mode

and turn mark off.

DATA

: Data key

When the meter is in measurement mode, pressing this key causes the mark to
flash and the currently-displayed conductivity and temperature measurement values to be
temporarily stored. Pressing the

key while the mark is flashing stores

F/ENT

the data and returns to measurement mode.
To abort data storage, press the

DATA

key or

MEAS

key again; the mark

turns off and the meter returns to measurement mode.

MEAS

: Measurement key

In measurement mode, pressing this key toggles between different LCD display types
(refer to Section 3.2, “Measurement Procedures”).

If this key is pressed while in any mode other than measurement mode, the instrument
returns to measurement mode. If you want to cancel any operation, pressing this key
returns you to measurement mode.

: Setting change key

Used to change settings.

4-2

IM 12D03D02-01E

4. Keyswitch Functions

F/ENT

: Entry key

In measurement mode, pressing this key switches the meter to function mode (see
Section 4.3, “Function Modes”). This key is also used to confirm set values.

Buzzer (Beep) sound

When a key is pressed, the buzzer beeps. Where the buzzer beeps once, or when it beeps
three times continuously, the meaning is as follows:

(1) When the buzzer beeps once:

This means that key operation was accepted.

(2) When the buzzer beeps three times continuously:

This means that the key operation was not accepted.

To disable the above key entry beep, refer to Sec. 4.3 (11) Set buzzer ON/OFF (bZ.o)
panel.

Note: the sound volume level of the beep cannot be adjusted by the user.

IM 12D03D02-01E

4-3

4. Keyswitch Functions

4.2 Liquid Crystal Display and Display Items

Displays and their explanations are shown below.

Remaining battery life display

Temp. compensation setting mode

Manual range setting mode
Data save mode

HOLD mode

Calibration with std. solution
Cell constant set mode

(1) Remaining battery life display

Remaining battery life is always displayed stepwise. When display is , battery is
normal. When a flashing is displayed, battery power is low. Replace the

batteries immediately if the above flashing battery symbol appears. Press
confirm that display turns off, then refer to Sec. 2.1 for battery replacement procedure.

(2) T emperatur e compensation setting mode

This mark appears when temperature compensation is being set (refer to Temperature
compensation setting (t.Co) panel in Section 4.3 (2))

(3) Manual range setting mode

Normally autoranging is used, and optimum range is selected automatically, but if fixed
(manual) range setting is used then this mark appears (refer to Range selection (rnG)
panel in Section 4.3 (3)).

(4) Data save mode

This mark appears when measured data are stored or when already-stored data are
accessed (see Operation of DATA key in Section 4.1, or Display stored measurement
value in Section 4.3 (1)).

(5) HOLD mode

This mark appears while measured data are being temporarily held (refer to Operation of

key in Section 4.1).

HOLD

POWER

F040201.EPS

and

(6) Calibration with standard solution

This mode display appears when the calibration with standard solution is conducted
(refer to Calibration with standard solution (CAL) panel in Section 4.3 (5)).

(7) Cell constant set mode

This mode display appears when the sensor cell constants are manually set (refer to Cell
constant setting (C.C) panel in Section 4.3 (4)).

4-4

IM 12D03D02-01E

4.3 Function Modes

Outline

4. Keyswitch Functions

A variety of functions are supported by function mode. Press the

F/ENT

key to switch

from measurement mode to function mode. This mode supports the functions listed in
the table below.

Note: The last selected and executed item is displayed when you switch to function

mode. Pressing the keys displays the items listed in Table 4.1 in turn.

Methods of setting items

Use the keys to move to the desired item. While the desired item is flashing,
press the

To return from the function mode to the measurement mode, press the

Item*

dAt
t.Co

rnG
C.C
CAL

dEL.A
dAtE

tIME
ALM
A.oFF
bZ.o
SC.U
tP.U
VEr
dFLG

F/ENT

key to set each item in detail.

Table 4.1 Items Set in Function Mode

1

Description

Display stored measurement value
Temperature compensation setting
Range selection

Cell constant setting
Calibration with standard solution

Delete all stored measuring data
Date setting

Time setting
Alarm time setting

Set Auto Power Off interval
Set buzzer ON/OFF
Set measurement unit
Set temperature unit

Version number display
Defragment storaged data

*1: Numeric display used to simulate alphabetic character display.
*2: 2: This data is not user-settable
*3: The standard cell constant for the connected sensor is displayed.

Default*

no dAtA

0.00 %/ 8C
Auto
Standard cell constant*

2

2

2004, January, 1
0 hour 0 minute
oFF
20 min
on
S/cm

8C

2

2

2

3

MEAS

For details, refer to:

Item (1)
Item (2)
Item (3)
Item (4)
Item (5)
Item (6)
Item (7)
Item (8)
Item (9)
Item (10)
Item (11)
Item (12)
Item (13)
Item (14)
Item (15)

key.

T0401.EPS

IM 12D03D02-01E

4-5

4. Keyswitch Functions

Details about how to set each item are provided below.

(1) Display stored measurement value (dAt) panel

Used to display stored measurement values. mark appears in the top left corner
of the display. The last-stored conductivity and temperature values are displayed first.

The stored data item number flashes in the lower left corner. Pressing the
displays the date and time of this stored data, and pressing this key again allows

individual data to be deleted (refer to the figure next page).
Pressing keys allows you to scroll through all past data. If no data are stored,

“no dAtA” is displayed at the bottom of the display.

• Individual deletion of stored data items

After displaying date and time of this stored data, pressing the
panel with dEL. Pressing the

F/ENT

key on this panel switches to the Data Delete

panel.
First is flashing, so use keys to switch to flashing , then press the

F/ENT

key to delete the stored measurement data that is currently displayed.

• Stored data item numbers after deletions

When you display the dEL panel, the number displayed at the bottom left indicates the
stored data number relative to the beginning of the data store. This does not necessarily
represent the number of stored data. If you delete a data item, item numbers of data that
follow it will be decreased by one (see explanation below).

• Data display after deletion

If a data item is deleted, the data item after it is displayed. If there is no data after it (i.e.
it was the last stored data item, the data item before it (if any) is displayed.

When data item 012 (lastest data) is deleted:

DATA

key

DATA

key displays a

4-6

Item 012 is deleted,
so item 011
becomes the latest

When data item 011 is deleted

Item 011 is deleted,
so item numbers of
following items (only
item 012 in this case)
are decremented by 1.

F040300.EPS

IM 12D03D02-01E

4. Keyswitch Functions

Stored measurement data

Latest data

F/ENT

When no stored data.

F/ENT

DATA

F/ENT

to display other data

DATA DATA

"Delete stored data" panel

DATA

Delete
stored data

F/ENT

Year that data was storedDsy, month data was stored

DATA

Time stored

IM 12D03D02-01E

F/ENT

F040301.EPS

4-7

4. Keyswitch Functions

(2) Temperature compensation setting (t.Co) panel

This panel is used to change the temperature compensation type and temperature
coefficient setting. The TEMP mark appears on the panel.

• Automatic temperature compensation for NaCl solution

Press the keys to select NaCl . Then press the

• Manual temperature compensation coefficient setting

Press the keys to select %/8C (or %/8F). Then press the

F/ENT

key.

F/ENT

key. Use the

keys to set the temperature coefficient. Then press the

F/ENT

Use keys to select

F/ENT

For manual setting: When %/8C (or %/8F) is displayed,
set the temperature coefficient with

keys. Press key to complete
the temperature coefficient setting.

F/ENT

For NaCl: When NaCl is displayed,
press key to confirm.

F/ENT

F/ENT

F040302.EPS

key.

4-8

IM 12D03D02-01E

4. Keyswitch Functions

(3) Range selection (rnG) panel

Change the current measuring range. Use the keys to change between autoranging
and fixed range. For fixed range, mark appears.

Relationships between automatic and fixed ranges for different sensors

For general-purpose sensor

(SC72-21, -23)

*1 *1

Autorange

For chemical-resistant sensor

(SC72-31)

Autorange

(Example)
For general-purpose sensor (SC72-21, -23)
used with 0-200.0mS/cm

*1

Fixed range 5
(0-20.00mS/cm)

Fixed range 4
(0-200.0mS/cm)

Fixed range 3
(0-2.000mS/cm)

Fixed range 2
(0-20.00mS/cm)

Fixed range 1
(0-200.0mS/cm)

With sensor for high-conductivity

measurement (SC72-41)

Autorange

Fixed range 4

(0-2.000mS/cm)

Fixed range 3
(0-20.00mS/cm)

Fixed range 2
(0-200.0mS/cm)

Fixed range 1
(0-2.000S/cm)

With sensor for high-purity water

*1

measurement (SC72-11)

Fixed range 5
(0-20.00mS/cm)

Fixed range 4
(0-200.0mS/cm)

Fixed range 3
(0-2.000mS/cm)

Fixed range 2
(0-20.00mS/cm)

Fixed range 1
(0-200.0mS/cm)

Autorange

Fixed range 4

(0-40.0MVcm)

Fixed range 3
(0-2.000mS/cm)

Fixed range 2
(0-20.00mS/cm)

Fixed range 1
(0-200.0mS/cm)

F/ENT

Autorange

Press key

or key

*1

five times

Fixed range 1

F/ENT

Set range 1 fixed.

*1: Model no. of sensor alone is SC72SN-u. (refer to Sec. 1.6)

Refer to Relationships between automatic and fixed ranges... (above left)

F040303.EPS

IM 12D03D02-01E

4-9

4. Keyswitch Functions

(4) Cell constant setting (C.C) panel

This panel with the mark is used to set the cell constant manually.

Use the keys to set the cell constant. Then press the

F/ENT

key.

Typical cell constants are as follows:
For pure water sensor (SC72-11): 0.05 cm
For general-purpose (SC72-21, -23) and chemical-resistant sensors (SC72-31): 5 cm
Sensors for high-conductivity measurement: 50 cm

-1

-1

-1

When setting the cell constant, you should check the nameplate (attached to sensor cable)
for the model number and cell constant.

The cell constant can be set in the range 6 20% of standard cell constant. For example,
for general-purpose sensors with standard cell constant of 5 cm-1, a cell constant ranging
from 4.00 to 6.00 can be set.

Once the cell constant is set, it remains stored in memory even when batteries are
removed.

The general-purpose cell has the same cell constant whether used with SC72-21 or SC72­23 type.

Refer to Sec. 2.4 for cell constant setting procedure.

Use key to set
the cell constant. Then press

F/ENT

the key to complete setting.

F/ENT

F040304.EPS

4-10

IM 12D03D02-01E

4. Keyswitch Functions

(5) Calibration with standard solution (CAL) panel

This panel is used for calibration with standard solution. Refer to Sec. 5.4 for a
description of the calibration procedure. In CAL mode, the mark appears at the
top of the panel and all digits of the present measurement value flash.

After the measurement stabilizes, press the

F/ENT

key to display the measured value at

that time. Only the least significant digit flashes. Use the keys to set the desired
calibration value, then press the

F/ENT

key to complete the calibration.

The meter internal cell constant is changed after completing calibration with standard
solution. Referring to (4) cell constant setting (C.C) panel, confirm the updated cell
constant value and rewrite the cell constant (refer to the value on the plate attached to the
sensor cable. Rewritten cell constants remain even if batteries are removed.

To abort calibration using standard solution, press the

MEAS

key to return to

measurement mode.

All digits of measurement
value are flashing

Least significant digit is flashing

F/ENTF/ENT

Press the key to complete calibration.

F/ENT

F040305.EPS

IM 12D03D02-01E

4-11

4. Keyswitch Functions

(6) Delete all stored measuring data (dEL.A) panel

This panel is used for deleting all stored data.
When you switch to this panel, is flashing. Use the keys to select .

Press the

F/ENT

key to delete all the data completely.

F/ENT

to set

F/ENT

to execute delete all

F/ENT

to abort

(7) Date setting (dAtE) panel

Set the date for the meter; year (four digits), month, day in order.

Use the keys to set year, month, and day. Then press the
setting.

Year setting Month setting

F/ENT

F/ENT

F040306.EPS

F/ENT

key to complete

The calendar functions will be correct through to the year 2090.

4-12

Day setting

F/ENT

F/ENT

F040307.EPS

IM 12D03D02-01E

(8) Time setting (tIME) panel

For the converter, set the time (24-hour display), minutes in order.

4. Keyswitch Functions

Use the keys to set hours and minutes. Then press the
setting.

Hour setting (24-hr clock) Minute setting

F/ENT F/ENT

F/ENT

F/ENT

key to complete

F040308.EPS

IM 12D03D02-01E

4-13

4. Keyswitch Functions

(9) Alarm time setting (ALM) panel

Alarm Enable (ON) / Disable (OFF) and alarm occurrence time (hours and minutes) can
be set. Use the keys to set alarm time.

Alarm time setting methods are the same as for (8) Time setting (tIME).
Alarms sounds for about 15 seconds continuously. Acknowledge alarm by pressing any

key to stop alarm sound. If no key is pressed to acknowledge the alarm occurrence,
alarms sound for 15 seconds again three and six minutes after the preset alarm time.

Note: The day of the week is not displayed

F/ENT

alarm sounds
at preset time
every day

alarm sounds at
preset time

from Monday
to Friday

F/ENT

Hour setting (24-hr clock)

F/ENT

Minute setting

4-14

alarm sonds
once
at preset time

F040309.EPS

IM 12D03D02-01E

4. Keyswitch Functions

(10) Set Auto Power Off interval (A.oFF) panel

Set the time interval for the power to turn off automatically if no key is pressed during a
preset time interval. The Interval can be set to between 1 and 120 minutes. If “0
minutes” is set, automatic power OFF functions are disabled, so — without some care —
batteries won’t last very long.

Use
key to set

F/ENT

F/ENT

to confirm

F040310.EPS

(11) Set buzzer ON/OFF (bZ.o) panel

This panel is used to enable or disable the beep (“buzzer”) that sounds when keys are
pressed.

Use the keys to enable / disable. Then press the

F/ENT

key to complete setting.

Note this function does not disable the Time Alarm sound in (9) above.

F/ENT

F/ENT

to turn ON (enable).

F/ENT

to turn OFF (disable).

F040311.EPS

IM 12D03D02-01E

4-15

4. Keyswitch Functions

(12) Set measurement unit (SC.U) panel

Toggle the measurement value units between [S/cm] and [S/m].

Use the keys to toggle the measurement value units. Then press the
to complete setting.

F/ENT

F/ENT

to set

to toggle

(13) Set temperature unit (tP.U) panel

Toggle the temperature units between [8C] and [8F].

Use the keys to toggle the temperature units. Then press the
complete setting.

F/ENT

to toggle

F/ENT

F/ENT

key to

key

F040312.EPS

4-16

F/ENT

to set

F040313.EPS

IM 12D03D02-01E

(14) Version number dispaly (VEr) panel

Displays program firmware version number. Can’t be set by the user.

F/ENT

4. Keyswitch Functions

F040314.EPS

IM 12D03D02-01E

4-17

4. Keyswitch Functions

(15) Defragment storaged data (dFLG) panel

Up to 300 data can be stored. Unnecessary data can be individually deleted as in (1)
Stored measurement data panel (dAt). At the same time, individual deletion does not free

up memory occupied by deleted data, so may be displayed even though less
than 300 data are stored. In such a case, use defrag functions to compact storage and free

up the space occupied by deleted data, thereby allowing up to 300 data to be stored.
While data defrag is in progress, do NOT turn off the power. In addition, before starting

data defrag, check that the battery power is normal to avoid battery voltage dropout
during defrag.

• Performing data defrag

F/ENT

If the

key is pressed from the display shown below, flashes.

Use the keys to select , then press the

F/ENT

key. While defrag is in

progress, [WAIt] flashes (Note: if only a few data are deleted, you may not even see it).
When defrag is complete, [End] is displayed.

F/ENT

to confirm

(if only a few data are deleted, you may not see this)

After a few
seconds

F/ENT

F/ENT

to execute

to toggle

to abort

F040315.EPS

4-18

IM 12D03D02-01E

5. Handling of the SC72 Personal Conductivity Meter

5. Handling of the SC72 Personal
Conductivity Meter

5.1 Tips to Maintain Meter Performance

The SC72 meter appears to be very simple, but is a precision instrument. To ensure that
measurement accuracy is maintained, observe the following precautions regarding
preliminary setting, measurement, maintenance and storage.

Preliminary setting, measurement, maintenance and storage:

Measurement

Preliminary

setting

Storage

Table 5.1 Observe the following precautions

Setting cell constant

• Set specific electrode cell constant.

Preliminary
setting

Measurement

Maintenenace

Storage

Setting temperature coefficient

• Set liquid temperature coefficient when the standard temperature
conversion is required (see Section 2.5)
If standard temperature conversion is not requiresd, set 0.00.

• Select one of the three conductivity measurement ranges (0 to
200mS/cm, 0 to 200mS/cm, or 0 to 2S/cm) corresponding to the type of
electrode used.
Temperature measuring range is 0 to 808C.

• When measurement is completed, thoughly wash electrode to remove the
measured liquid.

• If the electrode gets stained or deformed, its cell constant may change.
In this case, calibrate the meter with standard solution (see Section 5.4).

• Avoid high-temperature, high-humidity storage locations.

Maintenance

F050101.EPS

T0501.EPS

IM 12D03D02-01E

5-1

5. Handling of the SC72 Personal Conductivity Meter

5.2 Washing the Electrode

Dirt or stains on the electrode may have an adverse effect on the cell constant, thereby
making accurate conductivity measurement impossible. Therefore, after measurement,
rinse the electrode in clean water (for example, tap water) to remove stains. Even if
staining is not apparent, the sensor performance may have changed. If so, wash the
electrode by moving the sensor up and down in hydrochloric acid (about 0.1 mol/l) or
water with a little neutral detergent dissolved in it. [For general-purpose and pure-water
sensors: if the electrodes are difficult to clean, wipe them gently from top to bottom with
a cotton wool swab.] After cleaning the electrode, rinse it in water.

• General-purpose sensor

(The figure below shows the general-purpose sensor with the cover removed).
Remove the cover, and wipe stains off the electrodes (inner electrode and tip element)

with a cotton swab. Rinse in a cleaning solution consisting of water containing a little
neutral detergent, to remove stains from the electrode. After cleaning, wipe the electrode
element (inner and edge electrodes) with tissue paper or cotton wool.

Inner electrode (titanium) Edge electrode (titanium)

F050201.EPS

• Sensor for high-purity water measurement

Remove the reference electrode part, and wipe the electrode elements (the shaded parts
in the figure) with tissue paper or cotton wool.

Cotton wool swab

Reference electrode contact

Internal electrode

Reference electrode

F050202.EPS

* Corrosion-resistant sensors and sensors for high-conductivity measurements
Use a beaker or the like containing water, dilute hydrochloric acid, or weak neutral

detergent; move the sensor up and down so it is immersed up to the air vent, and wash
in tap water to clean out the air vent.

5-2

IM 12D03D02-01E

5. Handling of the SC72 Personal Conductivity Meter

5.3 Cleaning and Drying Connector

If there is an electrical path between the connector pins, solution conductivity cannot be
measured correctly. Clean the connector (shown in the figure) with a dry cloth, or a cloth
moistened with pure undiluted alcohol, to remove moisture and/or stains. If necessary,
use a hair dryer to dry any section that is likely to be difficult to wipe.

O-ring

Wipe off stains and/or moisture on
meter connector with a dry cloth.

Check that there are no stains on
the O-ring.

Hot air

Use a hair drier if necessary to
remove moisture from
connector of sensor cable.

F050301.eps

CAUTION

For free from moisture, use pure undiluted alcohol to clean the connectors. Dry
connectors completely.

IM 12D03D02-01E

5-3

5. Handling of the SC72 Personal Conductivity Meter

5.4 Calibration with Standard Solution

Note: Calibration with standard solution means to measure a standard solution of

accurately-known conductivity and to adjust SC72 meter so that the displayed
measured value is the same as the known conductivity value of the standard
solution.

If the sensor has been used for a long time, and does not look clean despite washing,
recalibrate the SC72 meter with standard solution to check if cell constant is normal.

If “ ” occurs during calibration with standard solution, replace the sensor.
Note that if calibration with the standard solution shows that the cell constant has

changed, update the cell constant value on the sensor cable with the new data.

Notes for calibration with standard solution:

Types of standard solution

Use NaCl (sodium chloride) or KCl (potassium chloride) solutions.

(1) NaCl (sodium chloride) solution

When NaCl solution is used, the temperature coefficient of NaCl is built into the
temperature compensation functions of the meter so conductivity converted to 25 8C can
be readily obtained regardless of liquid temperature. Standard NaCl solution of 0.1 mol/l
(normal unit expressing concentration of solution) is available as an option from
Yokogawa. For more details, see Section 1.7.

When the sensor for high purity water measurement is used, dilute the standard solution
with pure water to obtain 0.001 ml/l solution of conductivity 1 mS/cm. Conductivity is as
follows:

0.1 mol - NaCl solution: conductivity 10.67 mS/cm at 258C

0.001 mol/l - NaCl: conductivity 123.9 mS/cm at 258C

(2) KCl solution

Table 5.2 describes how to make KCl solution of different concentrations, and lists their
conductivities.

5-4

Table 5.2 How to make KCl solutions, and their conductivities

(based on JIS K 0102)

KCl

solution

A

B

C

D

How to make

Dissolve 74.2460g of KCl in water to
get 1l at 20618C.

Dissolve 7.4365g of KCl in water to get
1l at 20618C.
Dissolve 0.7440g of KCl in water to get
1l at 20618C.

Dissolve 100ml of standard solution C
avobe in water to get 1l at 20618C.

KCl standard solution, mS/cm

08C

65176

7138

773.8

188C
97838

11167

1220.5

IM 12D03D02-01E

258C
111342

12856

1408.8

146.93

T0502.EPS

5. Handling of the SC72 Personal Conductivity Meter

* Before calibrating the meter with standard solution, check that the electrode is clean. If
stains are found, clean the electrode first. Also check that the cover (of general-purpose
sensor) and outer electrode (of sensor for high purity water measurement) are secure.
Cell constant is affected by stains or loose cover.

When calibrating, ensure that measuring range is set so that you can enter conductivity to
as many digits as possible. For example, in the table above, the conductivity of standard
solution C at 258C is 1408.8. If the meter is set to autorange, or to a manual range of 0
to 2.000 mS/cm, you could set this as 1.409 (four digits). However if the range were set
to 0 to 200.0 mS/cm, you could only enter conductivity value as 1.4 (only two digits
accuracy, which is inadequate for calibration with standard solution.

Before calibrating the meter with standard solution

Check and set the following items before calibrating the meter with standard solution.

(1) Check sensor for stains

Check that there are no stains on the sensor. Also check that the meter cover (for
general-purpose sensor) or outer electrode (for sensor for high purity water sensor) are
not loose.

(2) Setting temperature coefficients

When the meter is calibrated with a NaCl solution, set a temperature coefficient
(indicated by “NaCl”) for NaCl solution. When it is calibrated with a KCl standard
solution, set a temperature coefficient of 0.00 (%/8C).

(3) Standard solution temperature

For a NaCl standard solution, check that the standard solution temperature is in the range
258C 6 108C.

For a KCl standard solution, stabilize its temperature at 258C 6 18C or 188C 6 18C.
If it is difficult to maintain the above temperatures, set the temperature coefficient of KCl

standard solution in the meter. To find the temperature coefficient, refer to table 5.2
above and to Section 7.3, “Temperature Compensation and Finding Temperature
Compensation Coefficient.”

IM 12D03D02-01E

5-5

5. Handling of the SC72 Personal Conductivity Meter

Procedures for calibration with standard solution

POWER

Water

Std. sol.

Wash sensor with
water completely.

Whole measurement value
is flashing

Wait until the measured
value is stable.

Thoroughly wipe off the
washing water from the

electrodes before immersing
the sensor in standard solution.

F/ENT

F/ENT

Set the conductivity of
the standard solution.

F/ENT

Select
CAL mode

Least significant figit of the
measuremet value is flashing

Complete the calibration

F/ENT

Refer to Section 4.3, “Function Modes,” for temperature coefficient and cell constant
settings.

5-6

F050401.EPS

IM 12D03D02-01E

5. Handling of the SC72 Personal Conductivity Meter

5.5 Storage and Maintenance

• Method of storage

Care is required when storing the SC72 meter. To maintain the SC72 meter in good
condition, observe the following:

(1) After measurement, thoroughly wash the sensor in water.
(2) Leave the sensor connected to the meter body, to protect the connector from

staining. Connector contamination could affect connector leakage resistance and
thus conductivity reading accuracy, or affect the waterproofing afforded by the O­ring.

(3) Do not place any object on top of the sensor or on the top of SC72 meter.

• Storage location

When the SC72 meter is not being used, store it in a safe place. If it is to be stored for a
long time, store it:

* In a dry place (low humidity) at normal temperatures.
* Out of direct sunshine.
* Do not store it in a corrosive gas atmosphere.
* In a location free from water condensation.

• Replacing O-rings or gaskets

Gaskets for the battery box and O-rings for sensor connections can be replaced. If they
are very dirty or damaged, replace them with new ones.

CAUTION

When installing O-rings and gaskets, clean them and their mounting surface with a cloth
moistened with alcohol so that they are free from dirt. Otherwise, water resistance may
not be assured.

IM 12D03D02-01E

5-7

5. Handling of the SC72 Personal Conductivity Meter

(1) Replacing O-rings

Install the O-ring on the cylindrical flat part as shown in the figure.

O-ring

(2) Replacing gaskets

Install the gasket with its raised part facing downwards on the groove of th meter case.
Gaskets are symmetrical (on the right and left, and on the front and rear).

F050501.EPS

Gasket

SC72 meter top

Raised part

5-8

F050502.EPS

IM 12D03D02-01E

6. Troubleshooting

6.1 Causes of Abnormal Conductivity Display

The measured temperature is stable, but the conductivity reading is unstable, or an
unrealistic value is displayed, check the following:

(1) Is maintenance required, and has handling of the meter been adequate?
(2) Does the battery need replacement?
(3) Is SC72 meter unserviceable?

If any problem is evident, follow the procedure shown in Section 6.2 to determine the
cause and fix the problem. If you cannot fix it, contact your nearest Yokogawa sales
office.

d Displayed value unstable

Abnormal

d Displayed value unrealistic
d Error message displayed

Components need replacement

d Battery

Needs maintenance

d Needs recalibration with standard solution
d Electrode stained
d Electrical leakage in connector

6. Tr oubleshooting

IM 12D03D02-01E

SC meter failure

d Contact Yokogawa.

F0601.EPS

Figure 6.1 Causes of abnormality

6-1

6. Tr oubleshooting

6.2 Error Messages and Corrective Action

Table 6.1 Error Message

Error message

Err1
Err2
Err3
Err6

or

*1 Alphabet values simulated on a numeric display

*1

Name

Temperature compensation computation value out of range
Out of temperature measurement range
Calibration error
Meter electronics failure
Out of measuring range

(1) Err1 Temperature compensation computation value out of range

Cause:

When the standard temperature conversion is made to conductivity at 258C, this
instrument performs temperature compensation computation based on the preset
temperature coefficient.

Err1 is displayed in cases where temperature compensation computation is impossible
because the preset temperature coefficient is improper or a solution with a large
temperature coefficient is measured at temperatures lower or higher than 258C.

Corrective action:

* Reset the temperature coefficient to the correct value.
* Measure solution at about 258C.

(2) Err2 Out of temperature measurement range

Cause:

This error occurs if the measurement liquid temperature is outside the range -10 to
1208C, or if sensor cables are disconnected.

Note: The liquid temperature should never be outside the range 0 to 808C.

Corrective action:

* Set the liquid temperature to 0 to 808C.
* Replace the sensor. (Refer to Sec. 1.6)

T0601.EPS

6-2

IM 12D03D02-01E

6. Tr oubleshooting

(3) Err3 Calibration error

Cause:

When the calibration with standard solution is made, each time cell constants are
changed. Err3 occurs if the conductivity of the standard solution is wrong, or changed
cell constants are beyond 6 20% of the standard cell constant, due to a damaged sensor.

Corrective action:

* Use correct standard solution conductivity. (Refer to Sec. 5.4)
* Replace the sensor. (Refer to Sec. 1.6)

(4) Err6 Meter electronics failure

Cause:

Err6 occurs if the meter electronics fails.

Corrective action:

* Contact your nearest Yokogawa sales office.

(5) or Out of measurement range

Cause:

Conductivity is over the maximum value on the range.

Corrective action:

For manual ranging, select an appropriate range. If value exceeds maximum of highest
range (or when on autorange), use a more appropriate sensor (see Sec. 4.3 (3)).

IM 12D03D02-01E

6-3

6. Tr oubleshooting

6.3 Causes of Abnormal Measured Value

If error messages do not occur, but measured values seem incorrect, check the following:

* Are cell constants and temperature coefficients correctly set?
* Is the sensor properly connected to the meter?
* Are bubbles attached to the electrode portion?
* Is the sensor damaged or dirty?

6.4 Other conditions

• An alarm sounds

The alarm clock is set (see Sec. 4.3 (9) and change setting as required).

• T o Enable / Disable Key-Pr ess Audible Feedback (buzzer)

Refer to Sec. 4.3 (11) to change setting as required.

6-4

IM 12D03D02-01E

7. Measuring Principles of this Instrument

7. Measuring Principles of this
Instrument

7.1 What Is Conductivity?

Conductivity of a solution is defined as the ability of the solution to conduct electric
current. It is the reciprocal of the resistance between two sensors (both of areas 1 m2) at
a distance of 1 m apart in the solution.

1 S/cm = 100 S/m
Figure 7.1 shows the conductivities of typical solutions.

0.01 0.1110100 [mS/m]

0.1110100 1000 [mS/cm]

110100 1000 [mS/cm]

0.1110100 [S/m]

Pure
water

Deionized

water

Distilled

water

Figure 7.1 Conductivity of Typical Solutions

Organic

acid

Reservoir

water

Sea

water

Salt water
(1 to 27%)

Strong acid and

alkali solutions

F0701.EPS

IM 12D03D02-01E

7-1

7. Measuring Principles of this Instrument

7.2 Principles of Operation

AC power supply Ammeter

F0702.EPS

Figure 7.2 Operational Schematic

Dip two metallic plates (used as sensor electrodes) in a solution and apply a certain
voltage to flow current (I):

E

I = (1)

Rc

where Rc = solution resistance between two sensors
The relationship between Rc and conductivity K is expressed by:

Rc = J • (2)

where J = constant (also called cell constant) — determined by
sensor and distance between two sensors
From equations (1) and (2) above, we obtain:

K = • I (3)

E and J are constant, so the conductivity (K) can be obtained by
measuring the current (I).

1

K

J

E

7-2

IM 12D03D02-01E

7. Measuring Principles of this Instrument

7.3 Temperature Compensation and Finding Temperature

Compensation Coefficient

• Temperatur e Compensation

Table 7.1 shows the conductivity ratio at each liquid temperature when the conductivity
of a NaCl solution at 258C is 1.

Table 7.1 Conductivity Ratios at Different Temperatures in

NaCl solutions

08C258C

0.542 11.531

508C

758C

2.103

1008C

2.677

T0701.EPS

As shown in the above table, liquid conductivity changes with liquid temperature. So, in
order to compare conductivities, conductivity values at a fixed liquid temperature are
needed. This SC72 meter includes standard temperature conversion functions, to display
a liquid conductivity value converted to 258C, so this meter can be used for such
conductivity measurement comparisons. Temperature compensation coefficients of an
NaCl solution are stored in the SC72 meter. No other temperature coefficient setting is
required (for NaCl solutions).

Table 7.2 shows temperature coefficients of various electrolytic solutions.

Table 7.2 Temperature Coefficients of Electrolytic Solutions

Solutions

Lithium benzoate solution

Sodium acetate solution
Potassium chloride solution
Sodium hydroxide solution
Sulfuric acid

• Finding Temperature Coefficient

If temperature coefficient tables containing the liquid to be measured can not be found,
measure conductivity twice at two liquid temperatures between 10 and 308C with
temperature coefficient set to 0.00 and use the equation shown below to find approximate
temperature coefficient (a).

Temperature coefficient (%/8C)

1mol/l 1/10mol/l

---

2.20

1.74

1.74

1.07

2.28

2.20

---

---

---

1/1000mol/l

2.28

2.20

1.98

1.87

1.38

T0702.EPS

IM 12D03D02-01E

7-3

7. Measuring Principles of this Instrument

a = Temp. coef. 3 100 (%/8C)

K 2 K

2

1

K ( t 2 25 ) 2 K ( t 2 25 )

1

221

where t , t : liquid temperature (8C)

12

K : conductivity at t

11

K : conductivity at t

22

(Calculation example)

To find the temperature coefficient of liquid with conductivity - 124.5 (S/cm at liquid
temperature 18.08C and 147.6 (S/cm at liquid temperature 31.08C, substitute t1 = 18.0,
t2 = 31.0, K1 = 124.5, K2 = 147.6 in the equation above, thus we can obtain:

a = 3 100

= 3 100

147.6 2 124.5

124.53(31.0225)2147.6 3(18.0225)

23.1

747.02(21033.2)

= 1.298

Set the temperature coefficient 1.30 in the SC72 meter (as meter allows three digits to be
entered).

• Checking if meter is working correctly

When the temperature coefficient already set is accurate, the conductivity displayed
should be constant regardless of liquid temperature (within permitted temperature range).
Check that the temperature coefficient already set is accurate. When the liquid
temperature is lowered, if a larger conductivity is indicated, the temperature coefficient
already set is too small; whereas, if a smaller conductivity is indicated, the temperature
coefficient already set is too large. In such a case, change the temperature coefficient
such that the measured conductivity does not change with temperature.

7.4 Wetted Part Materials of Sensors

• For general-purpose sensor

Titanium (sensor)
Polyphenylene sulfite resin, Polypropylene resin (insulated area and cover)
Fluoro rubber (O-ring)

• Sensor for high purity water measurement

SUS 316 stainless steel (electrode element)
Polypropylene resin (insulated area)
Fluoro rubber (O-ring)

• Chemical-resistant sensor

Glass, platinum black (electrode element)

Sensor for high-conductivity measurement

Glass, platinum black (electrode element)

7-4

IM 12D03D02-01E

Appendix

Key-Operation Flow Chart (for reference)

Typical screens are shown. Refer to the corresponding section in the body of the manual
for details.

Appendix

d When turn on power

POWER

First time used, or
after replace batteries

F/ENT

F/ENT

F/ENT

F/ENT

Toggle display type

MEAS

MEAS

MEAS

or

d Temporary hold

HOLD

HOLD

MEAS

IM 12D03D02-01E

F/ENT

d Storing data

DATA

DATA

MEAS

F/ENT

T01.EPS

1

Appendix

d Function Mode

Display stored measurement value

Temperature compensation

setting

Range selection

F/ENT

F/ENT

or

DATA

DATA

DATA

DATA

F/ENT

F/ENTF/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

T02.EPS

2

IM 12D03D02-01E

d Function Mode

Cell constant setting

Calibration with

standard solution

Delete all stored

measurement data

Date setting

Appendix

Time setting

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

d Switching to Function Mode d Reverting to Measurement Mode

Measurement status

F/ENT

Measurement status

MEAS

T03.EPS

IM 12D03D02-01E

3

Appendix

d Function Mode

Alarm time setting

Set Auto Power OFF

interval

Set buzzer ON/OFF

Set measurement unit

Set temperature unit

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

F/ENT

d Function Mode

F/ENT

F/ENT

Version number

display

F/ENT

F/ENT

F/ENT

Deflagment

storaged data

F/ENT

F/ENT

T04.EPS

4

IM 12D03D02-01E

Revision Record

Manual Title : Model SC72 Personal Conductivity Meter
Manual Number : IM 12D03D02-01E

Edition Date Remark (s)

1st Aug. 2004 Newly published
2nd Apr. 2008 Addition of information on EMC compliance: P.1-3

Addition of CAUTION: P2-2
Correction: P.1, 1-2, 1-6, 2-1, 2-3, 3-1, 3-3, 4-1. 4-5,

App-1, App-4

3rd Aug. 2009 Change of information on EMC compliance: P.1-3