Mettler Toledo InPro 6000G Instruction Manual

InPro®6000G Series Gas Phase Oxygen Sensors

Instruction manual Bedienungsanleitung Instructions d’utilisation

2 InPro 6800G/6850i G/6900i G/6950i GO212 mm

InPro 6000 G – Series © 12 / 15 Mettler-Toledo GmbH 52 206 477 Printed in Switzerland

English Page 3

Deutsch Seite 42

Français Page 82

© It is forbidden to reprint this Instruct ion Manual in whole or par t. No part of this manual may be repro duced in any form, or modified, co pied or distributed using electronic systems, in particular in the form of photo copies, photographs , magnetic or other recordings, without written c onsent of Mettler-Tol edo Gmb H, Process Analytics, CH-8902 Urdorf, Switzerland.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 3

1 Introduction.....................................................................4

2 Important notes ...............................................................5

2.1 Notes on operating instructions ..........................................5

2.2 Intended use ....................................................................5

2.3 Safety instructions.............................................................6

2.4 Examples of some typical applications................................7

2.5 Use in Ex-zones ...............................................................7

2.6 Ex-classification ATEX .......................................................8

2.6.1 Introduction......................................................................8

2.6.2 Rated data .......................................................................8

2.6.3 Special conditions.............................................................9

2.7 Ex-classification FM approved..........................................10

3 Product description........................................................11

3.1 General information ........................................................11

3.2 Principle ........................................................................11

3.3 Enhanced diagnostics (only for ISM types available) ..........13

3.4 Scope of delivery ............................................................14

3

.5 Equipment features .........................................................15

4 Installation....................................................................16

4.1 Mounting the sensor........................................................16

4.2 Connection ....................................................................16

4.2.1 Connecting the sensor to a AK9 cable ...............................16

4.2.2 Connecting the cable to the transmitter ..............................17

5 Operation ......................................................................18

5.1 Start-up and polarizing....................................................18

5.2 Calibration .....................................................................19

5.2.1 Purpose of calibration .....................................................19

5.2.2 What you have to know for calibration ..............................19

5.2.3 Single point calibration....................................................20

5.2.4 Dual point calibration......................................................20

6 Maintenance .................................................................21

6.1 Inspection of the sensor...................................................21

6.1.1 Visual inspection ............................................................21

6.1.2 Using the METTLER TOLEDO O

2

sensor master ...................22

6.1.3 Testing the sensor via a transmitter...................................23

6.1.4 ISM design.....................................................................24

6.2 Changing the electrolyte,

the membrane body or the interior body ............................25

7 Storage.........................................................................28

8 Product specification .....................................................29

8.1 Certificates .....................................................................29

8.2 Specifications.................................................................30

9 Ordering information .....................................................32

9.1 Sensors .........................................................................32

9.2 Transmitter.....................................................................32

9.3 Accessoires....................................................................32

9.4 Spare parts ....................................................................33

9.5 Cables...........................................................................33

9.6 Recommended housings .................................................33

10 Theory of the polarographic sensor.................................34

10.1 Introduction....................................................................34

10.2 Principle of the design of an oxygen electrode....................34

10.3 Parameters determining current ........................................38

10.4 Polarization voltage ........................................................38

10.5 Temperature...................................................................39

10.6 Dependence on flow........................................................39

10.7 Oxygen partial pressure – oxygen concentration.................39

Contents

4 InPro 6800G/6850i G/6900i G/6950i GO212 mm

InPro 6000 G – Series © 12 / 15 Mettler-Toledo GmbH 52 206 477 Printed in Switzerland

1

Introduction

Thank you for buying the InPro 6800G/6850 iG/ 6900 iG / 6950 iG sensor from METTLER TOLEDO.

The construction of the InPro series employs leading edge tech nology and complies with safety regulations currently in force. Notwithstanding this, improper use could lead to hazards for the user or a third-party, and/or adverse effects on the plant or other equipment.

Therefore, the operating instructions must be read and understood by the persons involv ed before work is started with the sensor.

The instruction manual must always be stored close at hand, in a place accessible to all people working with the InPro sensor.

If you have questions, which are not or insufficiently answered in this instruction manual, please contact your METTLER TOLEDO supplier. He will be glad to assist you.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 5

2

Important notes

2

.1 Notes on operating instructions

These operating instructions contain all the information needed for safe and proper use of the InPro 6800G / 6850iG/6900 iG/6950 iGsensor.

The operating instructions are intended for personnel entrusted with the operation and maintenance of the sensors. It is assumed that these persons are familiar with the equipment in which the sensor is installed.

Warning notices and symbols

This instruction manual identifies safety instructions and additional information by means of the following symbols:

This symbol draws attention to safety instructions and warnings of potential danger which, if neglected, could result in injury to persons and/or damage to property.

This symbol identifies additional information and instructions which, if neglected, could lead to defects, inefficient operation and possible loss of production.

2.2 Intended use

METTLER TOLEDO InPro 6800 G/6850iG/6900iG/ 6950 i G sensors are intended solely for inline measurement of the oxygen partial pressure in liquids and gases, as described in this instruction manual.

Any use of these sensors which differs from or exceeds the scope of use described in this instruction manual will be regarded as inappropriate and incompatible with the intended purpose.

The manufacturer/ supplier accepts no responsibility whatsoever for any damage resulting from such improper use. The risk is borne entirely by the user / operator.

Other prerequisites for appropriate use include: – compliance with the instructions, notes and

requirements set out in this instruction manual.

– acceptance of responsibility for regular inspection,

maintenance and functional testing of all asso ci ated components, also including compliance with local operational and plant safety regulations.

– compliance with all information and warnings

given in the documentation relating to the products used in conjunction with the sensor (housings, transmitters, etc.).

– observance of all safety regulations governing the

equipment in which the sensor is installed.

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– correct equipment operation in conformance with

the prescribed environmental and operational conditions, and admissible installation positions.

– consultation with Mettler-Toledo Process Analytics

in the event of any uncertainties.

2.3 Safety instructions

– The plant operator must be fully aware of the

potential risks and hazards attached to operation of the particular process or plant. The operator is responsible for correct training of the workforce, for signs and markings indicating sources of possible danger, and for the selection of appropriate, stateof-the-art instrumentation.

– It is essential that personnel involved in the

commissioning, operation or maintenance of these sensors or of any of the associated equipment (e.g. housings, transmitters, etc.) be properly trained in the process itself, as well as in the use and handling of the associated equipment. This includes having read and understood this instruction manual.

– The safety of personnel as well as of the plant

itself is ultimately the responsibility of the plant operator. This applies in particular in the case of plants operating in hazardous zones.

– The oxygen sensors and associated components

have no effect on the process itself and cannot influence it in the sense of any form of control system.

– Maintenance and service intervals and schedules

depend on the application conditions, composition of the sample media, plant equipment and signi ficance of the safety control features of the measuring system. Processes vary considerably, so that schedules, where such are specified, can only be regarded as tentative and must in any case be individually established and verified by the plant operator.

– Where specific safeguards such as locks, labels,

or redundant measuring systems are necessary, these must be provided by the plant operator.

– A defective sensor must neither be installed nor

put into service.

– Only maintenance work described in this operat-

ing instruction may be performed on the sensors.

– When changing faulty components, use only

original spare parts obtainable from your METTLER TOLEDO supplier (see spare parts list, “Section 9.4”).

InPro 6800G/6850i G/6900i G/6950i G O212 mm 7

– No modifications to the sensors and the acces-

sories are allowed. The manufacturer accepts no responsibility for damages caused by unauthorised modifications. The risk is borne entirely by the user.

2.4 Examples of some typical applications

Below is a list of examples of typical fields of application for the oxygen sensors. This list is not exhaustive.

Measurement in liquids:

– Biotech – Chemical applications – Brewing – Beverage filtration – Filling stations

Measurement in gases:

– CO2recovery – CO2purity – Product storage – Inert production – Offgas monitoring

2.5 Use in Ex-zones

Attention!

For an installation in Ex-zones please read the guidelines following hereafter:

1258

Ex-classification ATEX:

Ex ia IIC T6/T5/T4/T3 Ga/Gb Ex ia IIIC T69°C/T81°C/T109°C/T161°C Da/Db

Number of the test certificate:

SEV 14 ATEX 0169 X IECEx SEV 14.0026X

Ex-classification FM approved:

IS/ I, II, III /1/ABCDEFG /T6 Ta = 60 °C

- 53 800 002; Entity

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2.6 Ex-classification ATEX

2.6.1 Introduction

According to Directive 94/9/EC (ATEX 95) Appendix I, the O2oxygen sensors type InPro 6XXX is a devices of equipment group II, category 1/2G which, according to Directive 99/92/EC (ATEX 137) can be used in zones 0/1 or 1/2 or 1 or 2 as well as gas groups IIA, IIB and IIC, which are potentially explosive due to combustible substances in the temperature T3 to T6.

The requirements specified in EN 60079-14 must be observed during use / installation.

According to Directive 94/9/EC (ATEX 95) Appendix I, the O2oxygen sensors type InPro 6XXX is a devices of equipment group II, category 1/2D which, according to Directive 99/92/EC (ATEX 137) can be used in zones 20/21 or 21/22 or 21 or 22, which are potentially explosive due to combustible dust.

The requirements specified in EN 60079-14 must be observed during use / installation.

For the analog version of the O2oxygen electrode, the O2measurement circuit, temperature measurement circuit and data chip circuit are part of the common intrinsically safe system and are jointly connected to and operated by a separately certified transmitter.

The digital version of the O2oxygen sensor is connected to and operated by two-wire cable to the certified transmitter.

The intrinsically safe circuits are galvanically isolated from the non-intrinsically safe circuits up to a nominal voltage peak value of 375 V and from the earthed parts up to a nominal voltage peak value of 30 V.

2.6.2 Rated data

Analog O2Oxygen sensor

With type of protection: intrinsic safety to Ex ia IIC

O

2

measuring circuit, temperature measuring

circuit and data chip circuit

Only for connection to certified intrinsically safe circuits. Maximum values: Ui≤ 16 V, Ii≤ 190 mA, Pi≤ 200 mW Li= 0 (effective internal inductance) Ci= 900 pF (effective internal capacitance)

The values above apply, each as the sum of all the individual circuits of the associated intrinsically safe supply and evaluation unit (transmitter).

Digital O

2

Oxygen sensor

With type of protection: intrinsic safety to Ex ia IIC

Two-wire current circuit

Only for connection to certified intrinsically safe circuits. Maximum values:

InPro 6800G/6850i G/6900i G/6950i G O212 mm 9

Ui≤ 16 V, Ii≤ 30 mA, Pi≤ 50 mW Li= negligible Ci= negligible

2.6.3 Special conditions

–

The relationship between the maximum permissi-

b

le ambient or media temperature and tempera-

t

ure class, for category 1G applications, zone 0, is

s

hown in the following table:

Temperature class Max. ambient or

media temperature

T 6 68 °C T 5 80 °C T 4 108 °C T 3 160 °C

– The relationship between the maximum permissi-

ble ambient or media temperature and temperature class, for category 1D applications, zone 20, is shown in the following table:

Temperature class Max. ambient or

media temperature

T 69 °C 68 °C T 81 °C 80 °C T 109 °C 108 °C T 161 °C 160 °C

– The capacitance and inductance of the connecting

cable has to be considered.

– The O2Oxygen sensor type InPro 6XXX can be

used in / with the fittings InFit 76*-*** or InTrac 7**-***, or in / with other suitable fittings in potentially explosive areas.

– The metal body of the O2Oxygen sensors, or the

fittings InFit 76*-*** or InTrac 7**-***, or other appropriate fitting is optionally included in the routine pressure test of the system.

– The independent fitting used for installation of O

2

Oxygen sensor must be conductively connected to the equipotential bonding system.

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2.7 Ex-classification FM approved

Non-Hazardous Location

Hazardous (Classified) Location

Class I, Division 1, Groups A, B, C and D

Class II, Division 1, Groups E, F and G

Class III, Division 1

T6 Ta= 60 °C

Any FMRC Approved Single

Multi-Channel Barrier or Apparatus

Probe

Mettler-Toledo GmbH

Process Analytics

CH-8902 Urdorf

11/12/2003 F. Kogelmann

15/07/2005 F. Trefz

FM control drawing

Wir behalten uns alle Rechte an diesem Dokument und an allen Beilagen vor. Der Empfänger anerkennt

diese Rechte und wird die genannten Unterlagen nicht ohne unsere vorgängige schriftliche Ermächtigung

Dritten zugänglich machen oder ausserhalb des Zweckes verwenden, zu dem sie ihm übergeben worden sind.

Entity Parameters:

V

t

= 15V, I

t

= 30 mA, P

max

= 0.25W

C

i

= 0.1 µF, L

i

= 0 mH

Notes:

WARNING: substitution of components may inpair intrinsic safety.

1. No revision to this drawing is permitted without FMRC approval

2. V

max

> V

t

; I

max

> I

t

; (C

i

of all loops + C cable) < C

a

; (L

i

of all loops + L cable) < L

a

; P

max

or P

i

> P

0

3. Single Multi-Channel IS Barrier or Apparatus must be FMRC Approved

5. Installation must be in accordance with Article 500 of the NEC

®

(ANSI/NFPA 70)

and ANSI/ISA RP12.6.

4. Single Multi-Channel IS Barrier or Apparatus manufacturer's control drawings

must be followed when installing the System. IS Barrier or Equipment may be

installed within the Hazardous (Classified) location for which it is approved.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 11

3 Product description

3.1 General information

The oxygen sensor series InPro 6800G/6850iG/ 6900iG/6950iG with integrated temperature probe

are used for meas ure ment of oxygen at low and medium concentrations.

InPro 6xxxiG sensors with ISM functionality offer Plug and Measure as well as enhanced diagnostics features.

3.2 Principle

Amperometric oxygen sensors:

The amperometric oxygen sensors of METTLER TOLEDO base all on the same mearuring principle according to Clark. However different series are offered, which clearly differ in the number and arrangement of their electrodes and thus in their specifications:

• The measurement system of the InPro sensors

consists of a working electrode (cathode), a counter electrode (anode), a reference electrode and a guard ring electrode. The measurement system is separated from the process medium by an oxygen permeable membrane.

• The measuring technique in principle is alike with

all sensors.

• The transmitter supplies a constant voltage be-

tween cathode and anode.

• The electrolyte creates a conductive connection

between the electrodes.

• The oxygen molecules migrate from the measure-

ment medium through the membrane to the cathode to which the voltage is supplied and are reduced. At the same time, oxidation takes place at the anode.

• This causes a current to flow between the anode

and cathode which is directly proportional to the partial pressure of oxygen (pO2) in the process medium. With digital ISM sensors, the sensor itself converts the current into oxygen concentration and communicates the value to the transmitter.

• The guard ring electrode of the InPro 6900iG and

6950i G built into the sensor reduces the oxygen that migrates to the side of the cathode and can affect the measurement. The guard ring electrode therefore enables traces of oxygen to be precisely determined at even the lowest concentrations.

Note: Please refer to “Section 10–Theory of the polarographic sensor” for further information.

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ISM Sensors:

All oxygen sensors with the index “i” (6850i G, 6900i G, 6950i G) are equipped with ISM, Intelligent Sensor Management.

Principle: In the sensor head a chip is integrated, which takes over the entire monitoring and control of the sensor and, beyond that, stores all sensor data. This chip is responsed via the transmitter.

The following data are available permanently in the sensor: – type of sensor – serial no. – software version – hardware version – order no. – operating time – calibration time and calibration date – calibration table

To check the system, the following indicators are monitored: – temperature – slope – zero current – air current – polarization voltage – cathode current and voltage

Based on these informations, the transmitter calculates a wear monitor and displays it depending upon transmitter type differently. (see the respective instruction manuals)

ISM enables the connection of the digital sensor to the iSense™ Asset Suite. The user-friendly software allows to manage all sensor information and store it in a data base. Furthermore, the sensor can be calibrated via the iSense™ software.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 13

3.3 Enhanced diagnostics (

only for ISM types available)

DLI Dynamic Lifetime Indicator The dynamic lifetime

indication allows an estimation, when the sensor inner body is at the end of his lifetime, based on the actual stress it is exposed to. The sensor permanently takes the averaged stress of the past days into consideration and is able to increase/decrease the lifetime accordingly.

T

he following parameters affect the lifetime indicator:

Dynamic parameters:

– Temperature

– Oxygen value

Static parameters:

– Calibration history

– Zero and Slope

The sensor keeps the information stored in the builtin electronics and can be retrieved via a transmitter or the iSense asset management suite.

The alarm will be resetted if the Lifetime Indicator is not 0 days anymore (e.g. after connecting a new sensor or changes on the measurement conditions)

For amperometric oxygen sensors, the lifetime indicator is related to the inner-body of the sensor. After exchanging the inner-body, reset the lifetime indicator in the ISM setup menu (Menu Configure).

TTM Time to Maintenance:

This timer defines when the next electrolyte or membrane replacement should be done to maintain the best possible measurement performance. The timer depends on the DLI parameters.

The sensors InPro 6850iG / 6950iG are equipped additionally with an electrolyte level monitor, ELM.

The electrolyte level monitor, ELM, automatically sets the TTM to zero as soon as a critical electrolyte level in the sensor tip is reached.

The alarm needs to be reset in the menu ”ISM setup”. For oxygen sensors, the time to maintenance indicates a maintenance cycle for the membrane and electrolyte.

Note: The recommended initial value for the maintenance interval will be uploaded from the sensor to the transmitter and can be adapted according to the application experience of the user.

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ACT Adaptive Cal Timer:

This timer estimates when the next calibration should be performed to keep the best possible measurement performance. The timer is influenced by significant changes on the DLI parameters.

Note: The recommended initial value for the calibration interval will be uploaded from the sensor to the transmitter and can be adapted according to the application experience of the user.

3.4 Scope of delivery

Each sensor is supplied fully assembled and factorytested for correct function together with:

– a quality control certificate – inspection certificates 3.1

(complying with EN 10204)

Digital sensors must be filled with electrolyte before use.

See electrolyte order details at section „Spare Parts“,

9.3.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 15

3.5 Equipment features

12 mm sensor

METTLER TOLEDO ISM O

2

sensors are supplied with fitted membrane body but without electrolyte and covered with the protection cap and have been checked for proper function.

Anode (Pt) Cathode and Guard Ring

Protection Cap

Cap Sleeve (N-type)

O-ring (silicone FDA/USP VI)

Membrane Body

Retainer Nut

Reference (Ag/AgCl)

Interior Body

O-ring (9.0 3 1.0 mm, silicone FDA/USP VI)

Pg 13.5 Threaded Sleeve

AK9 Connector

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4

Installation

4

.1 Mounting the sensor

Important! Remove the protection cap before

mount ing the sensor.

Mounting the sensor in a housing

Please refer to the instruction manual of your housing explaining on how to mount the sensor in place.

Mounting the sensor directly on a pipe or a vessel

The 12 mm sensors can be mounted directly through a socket with inside thread Pg 13.5 and securely tightened via the Pg 13.5 threaded sleeve.

4.2 Connection

4.2.1 Connecting the sensor to a AK9 cable

Note: The sensor is connected to the transmitter via

a AK9 cable. The AK9 cable ensures a secure connection between the transmitter and the sensor under harsh industrial conditions. The robust watertight IP68 connector housing guarantees maximum process safety.

Do not touch the sensor at the AK9 connector plug!

Tightly screw the plug to fasten the two parts.

Admissible mounting position

Zulässige Einbaulage

Positionement de montage admis

I

nadmissible angle

Unzulässiger Winkel

Angle non admissible

52910094ME

15° 15°

InPro 6800G/6850i G/6900i G/6950i G O212 mm 17

4.2.2 Connecting the cable to the transmitter

Note: For connecting the AK9 or VP cable to the ter-

minals of the transmitter, please refer to the instructions given in the METTLER TOLEDO transmitter manual.

AK9 Connector

Plug

AK9 Cable for Standard Use

O2 Transmitter

AK9 Cable or VP

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5

Operation

Important! Before using the sensors for the first time,

the electrolyte must be filled in (see “Chapter 6.2”).

5.1 Start-up and polarizing

Important! The protection cap must be removed be-

fore mounting the sensor in the process.

When the system is operated for the first time or if the sensor has been disconnected from the voltage source (transmitter or O2Sensor Master) for longer than 5 min utes, the sensor has to be polarized prior to calibration by connecting it to the operating O2transmitter or to a sensor master. After 6 hours, the sensor is fully polarized and ready for operation.

Attention: The InPro 6950i G should never be polarized at air!

During Polarization, we suggest to use the protection cap filled with cleaning and conditioning solution always (Chapter 7: Storage).

A shorter polarization period is sufficient if the sensor has been disconnected for only a few minutes. The following table serves to establish the correct polarization time in relation to the depolarization time.

Important! Setting of the polarization voltage on the transmitter for correct measurements:

– Standard applications InPro 6800 G / 6850iG:

– 675 mV

– Measurement of permanently low oxygen concen-

trations (<500 ppb in liquids or <10,000 ppm [vol.] in gases) in the presence of volatile acidic

Depolarization time1 Minimum required t

depol

[Min.] polarization time2 [Min.]

t

depol

> 30 360

30 > t

depol

> 15 6 3 t

depol

15 > t

depol

> 5 4 3 t

depol

t

depol

< 5 2 3 t

depol

1 Depolarization time: Time span in which the pola rization voltage is cut off from the sensor. This is the case: – during the time the cable is disconnected or no transmitter or sensor master is connected to the cable, or the transmitter has been disconnected from the current supply. – after changing the electrolyte or membrane body. In this case at least 6 houres of polariza tion must follow. 2 Polarization time: Time span during which the sensor is under a polarization voltage.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 19

components (e.g. carbon dioxide during measurements in breweries) e.g. InPro 6900iG/6950i G:

– 500 mV

Note: To ensure the supply of the correct polari za tion

voltage the transmitter must be set according to the transmitter manual.

5.2 Calibration

5.2.1 Purpose of calibration

Each oxygen sensor has its own individual slope and own individual zero point. Both values are subject to change, for example, through electrolyte consumption or after exchange of electrolyte or membrane body. To ensure high measurement accuracy of the sensor, a calibration must be carried out regularly, but at least after each change of electrolyte or membrane. Prior to calibration, the sensor has to be polarized for at least 6 hours.

Important: Please remove the protection cap from the sensor, rinse the sensor with water and dry it wait at least 10 minutes before starting calibration. Store sensor upright with membrane pointing down.

Note: To check if your sensor needs a recalibration, you may dry it and take it in the air to check that the reading is close to 100 %. If not, then the sensor needs a new calibration.

With ISM sensors all calibration data are stored in the sensor.

5.2.2 What you have to know for calibration

General remarks:

– For calibration in gas (e.g. air), the sensor

membrane must be dry outside, since adhering

water drops can falsify the measured oxygen value.

– Make sure that the oxygen saturation index of

the calibration medium is correct and remains constant during calibration.

– For correct calibration, a minimum flow rate of the

calibration medium is necessary.

– Make sure that all other parameters, such as

temperature and pressure, are constant.

For continuous applications, we recommend periodic recalibration in line with your requirements on accuracy, the type of process in operation and your own experience. The frequency of the need for re calibration depends very much on the specific application, and therefore appropriate intervals cannot be exactly defined here.

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5.2.3 Single point calibration

For applications measuring more than 1% Vol. O

2

gas a single point calibration is recommended. In this case the zero point is set manually to 0 nA. For measuring below 1% Vol. O2a zero point calibration with e.g. nitrogen gas is recommended.

B

y carrying out a single point calibration, the slope

o

r offset of the sensor can be set. The calibration

m

edium can be gas with known water-vapor satura-

t

ion (e.g. water-vapor saturated air).

After the sensor signal has stabilized, the complete meas uring system can be calibrated to the100% value of the desired measurable variable, e.g.100% air, 20.95% O

2

, or 8.26 ppm at 25°C (77 °F) and normal pressure (see instruction manual of the transmitter).

Zero-point calibration is recommended for the InPro 6950iG only when measuring less than 125 ppm (by vol. O

2

) in gases.

Attention! Incorrect zero point calibration is a frequent source for measurement error. For correct calibration, we recommend the use of carbon dioxide gas with a level of purity of at least

99.9995 % for measurements in CO

2

applications. For all other applications we recommend to use nitrogen (N2) gas.

After the sensor signal has stabilized (after 6…12 hours), the sensor can be calibrated through the

transmitter to zero% value of the desired measurable variable, e.g. 0% air, 0.0% O2, or 0.0ppm (see instruction manual for the transmitter).

5.2.4 Dual point calibration

By carrying out a dual point calibration both slope and zero point of the sensor can be set.

Important! In case of a dual point calibration, always start with the zero point calibration before

calibrating the slope.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 21

6

Maintenance

6

.1 Inspection of the sensor

6.1.1 Visual inspection

To check your sensor, we recommend the following procedure:

– The contacts of the connector must be dry.

Moisture, corrosion and dirt in the connector can lead to false readings.

– Check the cable for buckling, brittle areas or

ruptures.

– Before calibration always examine the membrane

foil for signs of damage. The foil must be intact and clean. Dirty membranes should be wip ed clean using a soft, moist tissue.

Note: An undulated membrane has no influence on the sensor performance, assuming the membrane is intact.

– The membrane body must be replaced if the

sensor has too long a response time, the reading is unstable or subject to drift, and if the sensor cannot be calibrated or the membrane shows sign of mechanical damage.

– Check the cathode area for discoloration, conta -

mination or cracks in the glass. If necessary rinse with demineralized water and clean with a clean soft brush or soft paper tissue.

Attention! Do not use any cleaning agents contai ning alcohol. This could damage the sensor or lead to fault current.

Attention! The glass body is fragile and sensitive to vibration.

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6.1.2 Using the METTLER TOLEDO O2sensor master

We recommend to use the METTLER TOLEDO O2 sensor master to check the status of your sensor as follows:

•

Connect the sensor to the O

2

s

ensor master.

The figure shows the Sensor Master (Order No. 52 200 892) for the analog sensor InPro 6800 G. For the digital ISM sensors use the Sensor Master digital ISM with order no. 52 206 329. For the digital Sensor Master the procedure is similar.

As soon as the sensor is connected to the O

2

sensor master, the polarization function is automatically activated. Please note: if the sensor was disconnected from the transmitter for longer than 5 minutes, the sensor must be polarized first (pola rizing time see “Section 5.1”) to get representative test results.

• Battery Check:

Push the switch to the left. If the battery is ok and

the O

2

sensor master is operational the green LED lights up. Otherwise, please consult the instruction manual of the O2sensor master.

• Sensor Check:

For this test the O

2

sensor must be fully polarized

and the membrane of the sensor tip must be dry

and clean outside.

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Switch

LED

InPro 6800G/6850i G/6900i G/6950i G O212 mm 23

Expose the sensor (connected to O2sensor master) to air. By pushing the switch to the right to position “Sensor check”, the O2sensor master checks whether the electrode current for air measurement is within the specified range, i.e. 2500 to 6000 nA for InPro 6950iG.

Air current Zero current in %

of the air current

6800 G 50– 110 nA <0.1 6850iG 50– 110 nA <0.1 6900iG 250– 500 nA <0.03 6950iG 2500– 6000 nA <0.025

If the green LED lights up the current for air

measurement is with in the specified range.

If the LED does not light up, you should check the battery of the O2sensor master (see instruction manual “Accessories”). If the battery is working, than there is probably a problem with your sensor. You should change the electrolyte and/or the membrane body of your sensor. If after a membrane change the LED still does not light up, this means that there is something wrong with the interior body of the sensor. You should then change it (see “Section 6.2”).

Important! The Sensor Check function only verifies the correctness of the electrode current for air measurement. In order to be absolutely sure of the functionality of the sensor, the residual signal in an oxygen free medium should also be controlled (see “Section 6.1.3”).

6.1.3 Testing the sensor via a transmitter

A periodic zero current measurement (no zero point calibration!) is recommended for verification of prop-

er sensor function.

Note: At the time you carry out the zero current measurement, the sensor must be polarized.

Zero current measurement can be done by using zero ing gel (order no. 30 300 435) or nitrogen (N2) or carbon dioxide (CO2) calibration gases with a purity of at least 99.995%, alternatively in a sample medium saturated with one of these gases.

After 2 minutes in an oxygen-free sample medium, the reading on the transmitter should drop to below 10% of the reading in ambient air, and within 10 minutes the value should have dropped to below 1 %.

If the measured values are too high, this suggests a depleted electrolyte or a defective membrane. In the first instance replace the electrolyte, and in the second case exchange both the membrane body and the electrolyte accordingly.

24 InPro 6800G/6850iG/6900iG/6950i GO212 mm

If after such procedures the above mentioned values are still not reached, replace the interior body. If this does not solve the problem send the sensor to your local METTLER TOLEDO representative for inspection.

6.1.4 ISM design

T

he integrated ISM function allows an advanced moni-

t

oring of the sensor. The following parameters are

s

tored in the sensor: – serial no. – type of sensor – order no. – calibration data – enhanced diagnostic data – slope – zero point

After powering up of the sensor the following automatic test procedures are running:

– dgital communication – plausibility of the stored calibration data

InPro 6800G/6850i G/6900i G/6950i G O212 mm 25

6.2 Changing the electrolyte, the membrane body o

r the interior body

Note: The InPro 6900iG and 6950iG use a special

electrolyte. This electrolyte ensures fast response time and together with the guard ring increases the signal stability of the sensor. The electrolyte must be exchanged on a regular basis or when the sensor has been exposed to air for more than 24 hours without a watering cap filled with conditioning solution.

If the membrane and/or the interior body exhibits signs of failure (long response time, increased current in an oxygen-free medium, mechanical damage, etc.) the membrane body and/or the interior body has to be replaced.

Warning! The O

2

electrolyte has a slight alkaline pH value. Contact of electrolyte with mucous membrane or eyes is to be avoided. Therefore protective

gloves and safety glasses have to be worn for the following dismantling works.

If such contact occurs, the affected area should be well rinsed with water. In the case of accident, or should ever any adverse signs appear, get immediate medical attention.

When changing the electrolyte, the membrane body or the interior body, please observe the following instructions (see also the following illustration):

Attention! Make sure that this maintenance step is carried out in clean place.

1. Unscrew the cap sleeve from the sensor shaft

and carefully pull it off the sensor.

2. Pull off the membrane body from the interior

body. If it is tight-fitted, eject by pushing it with the flat finger tip. Before electrolyte is refilled, the membrane body must be removed from the cap sleeve!

3. Rinse the interior body with demineralized water

and carefully dab it dry with a paper tissue.

Note: steps 4 to 7 may only be carried out

when changing the interior body.

4. Unscrew the retainer nut of the interior body with

an adjustable wrench or with a 9 mm wrench.

5. Remove the interior body by pulling it out of the

sensor shaft. If necessary use a plier.

Warning! Do not twist the interior body. Other -

wise the connection pins can be damaged.

6. Insert the new interior body in the sensor shaft.

Turn the interior body in the shaft until the slit of the interior body is aligned with the pin placed in the shaft.

26 InPro 6800G/6850iG/6900iG/6950i GO212 mm

7. Press the body in the shaft and screw the new

retainer nut in place. Only hand tighten the retainer nut using a small wrench. Applying a too high torque (>2 Nm) may damage the sensor.

8. Examine the O-rings visually for mechanical

defects, and replace if necessary.

9. Half-fill the new membrane body with O

2

electrolyte.

Note: The electrolyte bottle is equipped with a

special pouring system. To ensure proper functioning, hold the bottle vertically, upsidedown.

Note: make sure that all air bubbles are removed from the membrane body. Air bubbles can be removed by carefully tapping on the membrane body.

10. Slip the membrane body over the interior body while holding the sensor in a vertical position. The excess electrolyte will be displaced and have to be removed with a paper tissue.

Important! No electrolyte, sample media or

contamination may be present between the membrane body and the cap sleeve. Please check carefully!

11. Carefully slip the cap sleeve over the fitted membrane body, holding the sensor in a vertical position and screw it tight. The cap sleeve must be clean and dry.

12. After each exchange of electrolyte or membrane body, the sensor has to be repolarized and re calibrated before it is ready for use.

1

⁄

2

1

⁄

2

O2 Electrolyte

Air

InPro 6800G/6850i G/6900i G/6950i G O212 mm 27

Replacement of the interior body

Anode (Pt) Cathode and Guard Ring

O-ring (silicone FDA/USP VI)

Membrane Body

Retainer Nut

Reference (Ag/AgCl)

Interior Body

O-ring (9.0 3 1.0 mm, silicone FDA/USP VI)

P

g 13.5 Threaded Sleeve

A

K9 Connector

28 InPro 6800G/6850iG/6900iG/6950i GO212 mm

7

Storage

When the sensor is stored without polarization for more than one week, the electrolyte has to be removed.

Always use clean water to clean the sensor membrane from outside.

Important: Never use alcohol or isopropanol or mixtures with these organic solvents.

P

repare the cleaning and conditioning solution as follows: Dissolve one tablet in 40 ml of deionized water and wait 5 minutes for the tablet to be completely dissolved. Fill the protection cap with this solution and place it over the tip of the sensor. This solution has some cleaning properties which will keep the membrane free of microorganisms. In case you do not have any cleaning and conditioning set, you may also use checking gel or deaerated water in the protection cap. Before mounting the sensor in the process, always remove the protection cap and rinse the tip of the sensor with water.

Attention! If the storage period of the sensor without current supply (transmitter, sensor master) exceeds 1 week, the sensor should be stored dry, i.e. without any electrolyte in the membrane body. A sensor being stored dry (without electrolyte in the membrane body) may on no account be connected to the O

2

sensor master or any other polarization

module.

InPro 6800G/6850i G/6900i G/6950i G O212 mm 29

8

Product specification

8

.1 Certificates

Each sensor is delivered with a set of 3.1 certificates (complying with EN10204).

All wetted metal parts (sensor shaft, cap sleeve and membrane body) are identified with a engraved symbol corresponding to the heat number on the paper certificate delivered with the sensor.

Each wetted metal part (sensor shaft, cap sleeve and membrane body) is polished in order to get a surface roughness lower than 0.4 µm (16 µin). This represents a roughness grade number of N5 (according to ISO 1320:1992).

30 InPro 6800G/6850iG/6900iG/6950i GO212 mm

8.2 Specifications

InPro 6800 G/6850i G/6900i G/6950i G

Measurement principle Polarographic Clark electrode Working conditions

Pressure resistance 6800 G: 0.2…9 bar (measurement) 6850iG: 0.2…9 bar

6900i G: 0.2…9 bar

6950i G: 0.2…9 bar Mechanical pressure resistance Max. 12 bar Temperature limits –5…121°C

(mechanical) [23 …250 °F] Operating temperature limits 6800 G: 0 … 70 °C

(ambient) [32 …158 °F]

6850i G: 0…70°C

[32…158°F]

6900i G: 0…70°C

[32…158°F]

6950i G: 0…40°C

[32…104°F]

(sterilizable)

Specification

Temperature compensation Automatic Cable connection AK9 O-ring material Silicone, FDA and

USP Class VI approved

Kalrez Membrane material PTFE/ Silicone/ PTFE

(reinforced with steel mesh)

Kalrez Material sensor body 316L stainless steel

(wetted parts) Surface roughness of N5 (R

a

= 0.4 µm [16µin])

wetted metal parts Quick disconnect interior body Standard Cathode Pt Anode 6800 G: Ag

6850i G: Pt

6900i G: Ag

6950i G: Pt Guard ring 6800 G: –

6850i G: –

6900i G: Pt

6950i G: Pt Reference Ag

Dimensions

Sensor diameter

 6800 G: 12 mm

6850i G: 12 mm

6900i G: 12 mm

6950i G: 12 mm Immersion length (a) 120, 220 mm

for 12 mm sensor [4.7, 8.66"]

Performance

Measurement range in O

2

Gas 6800 G: 300 ppm to100% (1 bar) 6850iG: 300 ppm to 100% (1 bar) 6900iG: 50 ppm to100% (1 bar) 6950iG: 5 ppm to 20% (1 bar)

Accuracy 6800 G:  ± [1 % + 300 ppm]

6850i G:  ± [1% + 300 ppm] 6900i G:  ± [1% + 50 ppm] 6950i G:  ± [1% + 5 ppm]

Response time 90 % of final value in <30 s at 25°C/77°F

Sensor signal for ambient air 6800 G: 50…110 nA at 25°C/77°F 6850iG: 50 …110 nA 6900iG: 250...500 nA

6950iG: 2500... 6000 nA

Residual signal 6800 G <0.1 % of the signal in oxygen-free medium 6850iG: <0.1 % of the signal

6900i G: <0.03% of the signal 6950i G: <0.025% of the signal

Mettler Toledo InPro 6000G Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual