KROHNE OPTISONIC 7300 Wiring diagram

Ultrasonic gas flowmeter
Addendum for hazardous areas.
These additional instructions are an extension to the OPTISONIC 7300 Quick Start and
Handbook.
OPTISONIC 7300
OPTISONIC 7300OPTISONIC 7300
OPTISONIC 7300
Supplementary Instructions
Supplementary InstructionsSupplementary Instructions
Supplementary Instructions
© KROHNE 08/2018 - 4003791402 - AD EX OPTISONIC 7300 R02

CONTENTS
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OPTISONIC 7300
1 Introduction 4
1.1 Safety instructions from the manufacturer ..................................................................... 4
1.1.1 Copyright and data protection ................................................................................................ 4
1.1.2 Disclaimer ............................................................................................................................... 4
1.1.3 Product liability and warranty ................................................................................................ 5
1.1.4 Information concerning the documentation........................................................................... 5
1.1.5 Warnings and symbols used................................................................................................... 6
1.2 Manufacturer.................................................................................................................... 6
1.3 Safety instructions for the operator................................................................................. 7
1.4 Special conditions for safe use ........................................................................................ 8
1.4.1 General.................................................................................................................................... 8
1.4.2 Additional notes for safe operation ........................................................................................ 8
1.5 Approvals .......................................................................................................................... 9
1.6 OPTISONIC 7300 C/...-Ex ................................................................................................ 10
1.7 OPTISONIC 7000...-Ex..................................................................................................... 10
1.8 GFC 300 F/...-Ex.............................................................................................................. 11
1.9 Biogas versions .............................................................................................................. 11
1.10 Ultrasonic gas transducers.......................................................................................... 11
1.11 Technical data............................................................................................................... 12
1.12 Marking labels (examples) ........................................................................................... 13
1.12.1 Nameplate sensor OPTISONIC 7000...-Ex.......................................................................... 14
1.12.2 I/O sticker............................................................................................................................ 15
2 Temperature limits 16
2.1 General ........................................................................................................................... 16
2.2 GFC 300 F/...-Ex.............................................................................................................. 16
2.3 OPTISONIC 7300 C/...-Ex ................................................................................................ 16
2.4 OPTISONIC 7000...-Ex..................................................................................................... 18
3 Connection of separate systems 19
3.1 General ........................................................................................................................... 19
3.2 Cable marking ................................................................................................................ 19
3.3 Equipotential bonding..................................................................................................... 19
3.3.1 Flow sensor........................................................................................................................... 19
3.3.2 Signal converter.................................................................................................................... 19

CONTENTS
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OPTISONIC 7300
4 Electrical connections 20
4.1 General ........................................................................................................................... 20
4.2 Cable glands ................................................................................................................... 22
4.3 Field Wiring..................................................................................................................... 22
4.4 Non-"Ex i" I/O connections............................................................................................. 23
4.5 "Ex i" I/O connections.....................................................................................................25
5 Maintenance 27
5.1 Maintenance ................................................................................................................... 27
5.2 Before and after opening................................................................................................ 27
5.3 Replacement of mains fuse............................................................................................ 28
5.4 Exchange of electronics unit .......................................................................................... 29
5.5 Service / repair information ........................................................................................... 31
5.6 Form (for copying) to accompany a returned device ..................................................... 32
5.7 Disposal .......................................................................................................................... 32
6 Notes 33

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1.1 Safety instructions from the manufacturer
1.1.1 Copyright and data protection
The contents of this document have been created with great care. Nevertheless, we provide no
guarantee that the contents are correct, complete or up-to-date.
The contents and works in this document are subject to copyright. Contributions from third
parties are identified as such. Reproduction, processing, dissemination and any type of use
beyond what is permitted under copyright requires written authorisation from the respective
author and/or the manufacturer.
The manufacturer tries always to observe the copyrights of others, and to draw on works created
in-house or works in the public domain.
The collection of personal data (such as names, street addresses or e-mail addresses) in the
manufacturer's documents is always on a voluntary basis whenever possible. Whenever
feasible, it is always possible to make use of the offerings and services without providing any
personal data.
We draw your attention to the fact that data transmission over the Internet (e.g. when
communicating by e-mail) may involve gaps in security. It is not possible to protect such data
completely against access by third parties.
We hereby expressly prohibit the use of the contact data published as part of our duty to publish
an imprint for the purpose of sending us any advertising or informational materials that we have
not expressly requested.
1.1.2 Disclaimer
The manufacturer will not be liable for any damage of any kind by using its product, including,
but not limited to direct, indirect or incidental and consequential damages.
This disclaimer does not apply in case the manufacturer has acted on purpose or with gross
negligence. In the event any applicable law does not allow such limitations on implied warranties
or the exclusion of limitation of certain damages, you may, if such law applies to you, not be
subject to some or all of the above disclaimer, exclusions or limitations.
Any product purchased from the manufacturer is warranted in accordance with the relevant
product documentation and our Terms and Conditions of Sale.
The manufacturer reserves the right to alter the content of its documents, including this
disclaimer in any way, at any time, for any reason, without prior notification, and will not be liable
in any way for possible consequences of such changes.

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1.1.3 Product liability and warranty
The operator shall bear responsibility for the suitability of the device for the specific purpose.
The manufacturer accepts no liability for the consequences of misuse by the operator. Improper
installation or operation of the devices (systems) will cause the warranty to be void. The
respective "Standard Terms and Conditions" which form the basis for the sales contract shall
also apply.
1.1.4 Information concerning the documentation
To prevent any injury to the user or damage to the device it is essential that you read the
information in this document and observe applicable national standards, safety requirements
and accident prevention regulations.
If this document is not in your native language and if you have any problems understanding the
text, we advise you to contact your local office for assistance. The manufacturer can not accept
responsibility for any damage or injury caused by misunderstanding of the information in this
document.
This document is provided to help you establish operating conditions, which will permit safe and
efficient use of this device. Special considerations and precautions are also described in the
document, which appear in the form of icons as shown below.

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1.1.5 Warnings and symbols used
Safety warnings are indicated by the following symbols.
• HANDLING
HANDLINGHANDLING
HANDLING
This symbol designates all instructions for actions to be carried out by the operator in the
specified sequence.
i RESULT
RESULTRESULT
RESULT
This symbol refers to all important consequences of the previous actions.
1.2 Manufacturer
The instrument is developed and manufactured by:
KROHNE Altometer
Kerkeplaat 12
3313 LC Dordrecht
The Netherlands
For information, maintenance or service please contact your nearest local KROHNE
representative.
DANGER!
This warning refers to the immediate danger when working with electricity.
DANGER!
This warning refers to the immediate danger of burns caused by heat or hot surfaces.
DANGER!
This warning refers to the immediate danger when using this device in a hazardous atmosphere.
DANGER!
These warnings must be observed without fail. Even partial disregard of this warning can lead to
serious health problems and even death. There is also the risk of seriously damaging the device
or parts of the operator's plant.
WARNING!
Disregarding this safety warning, even if only in part, poses the risk of serious health problems.
There is also the risk of damaging the device or parts of the operator's plant.
CAUTION!
Disregarding these instructions can result in damage to the device or to parts of the operator's
plant.
INFORMATION!
These instructions contain important information for the handling of the device.
LEGAL NOTICE!
This note contains information on statutory directives and standards.

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1.3 Safety instructions for the operator
These additional instructions are an extension to the standard documentation and only apply to
the Ex versions of the OPTISONIC 7300 C/..., OPTISONIC 7000... and GFC 300 F ultrasonic
flowmeters. All technical information as described in the standard documentation is applicable,
when not specifically excluded, completed or replaced by the instructions in these additional
instructions.
General
•The relation between ambient temperature, process temperature and temperature class is
described in this manual.
•For details of the flameproof joints, contact KROHNE Altometer.
•Repairs on flameproof joints may only be performed in accordance with KROHNE Altometer’
s design specifications. Repair on basis of the values in tables 1 respectively 2 of IEC 60079-1
is not permissible.
WARNING!
• Do not change the device. Unauthorized changes affect the explosion safety of the devices.
• The prescriptions and regulations as well as the electrical data described in the EU type
examination certificate must be obeyed.
• Beside the instructions for electrical installations in non-hazardous locations according to
the applicable national standard (equivalent to HD 384 or IEC 364, e.g. VDE 0100), especially
the regulations in IEC/EN 60079-14 "Electrical installations in hazardous locations" or
equivalent national standard (e.g. DIN VDE 0165 Part 1) must be strictly followed.
• Installation, establishment, utilization and maintenance are only allowed to be executed by
personnel with an education in explosion safety!

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1.4 Special conditions for safe use
1.4.1 General
For information on the flameproof joints please contact your KROHNE representative. No repairs
are permitted to the flameproof joints.
To avoid the risk of ignition as a result of electrostatic charging, the equipment can not be used
in locations that have:
•High charge generating processes,
•Mechanical friction and separation processes,
•Electron emission (e.g. near electrostatic coating equipment) may occur.
1.4.2 Additional notes for safe operation
Connection conditions
1. When the terminal compartment of the OPTISONIC 7300 C/…-Ex compact ultrasonic gas flow-
meter and the connection box of the OPTISONIC 7000...-Ex ultrasonic gas flow sensor is de-
signed as flameproof enclosure "Ex db”, the following must be complied with:
•The device shall be connected with suitable cable glands or conduit systems that meet the
requirements stipulated in IEC/EN 60079-1, sections 13.1 and 13.2, and for which a separate
test certificate has been issued. If the device is connected to conduit systems, the required
sealing device shall be provided immediately at the cable entrance(s) of the enclosure
•Cable glands and blanking plugs of simple design must not be used
•Openings that are not used shall be sealed in compliance with the specifications in IEC/EN
60079-1, section 11.9.
•If the electrical connection is made in a potentially explosive area, the connecting cable
(unconnected cable end) of the remote ultrasonic gas flow sensor OPTISONIC 7000 …-Ex,
shall be connected in an enclosure that meets the requirements of an approved type of
protection in accordance with IEC/EN 60079-0, section 1.
2. The connecting cable(s) delivered with the ultrasonic gas flow meter system, shall be fixed and
routed so that it will be adequately protected against damage. The cable is rated for a continu-
ous operating temperature of maximum 100°C. The maximum temperatures listed in the tem-
perature classification tables in the next Chapter are limited based on the maximum operating
temperature of the connecting cable(s), cable gland(s) and/or blind plug (only in case of a sin-
gle-beam sensor).
3. The OPTISONIC 7300 C/…-Ex and OPTISONIC 7000…-Ex shall be included in the local equipo-
tential bonding system of the potentially explosive area.
Components attached or installed (i.e. terminal compartments, bushings, Ex-type cable glands,
connectors, etc.) shall be of a technical standard that comply with the specifications on the cover
sheet and shall have a separate examination certificate. The operating conditions specified in the
component certificates must be complied with.

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Warning messages
In potentially explosive atmospheres, the enclosure may only be opened after it has been
deenergized and the required waiting time has been obeyed (warning sign!).
For the OPTISONIC 7300 C/...-Ex compact gasflowmeter the waiting time is 35 minutes for
temperature class T6 and 10 minutes for temperature class T5. No waiting time(s) have to be
considered for temperature classes T4 ...T1
The warning message reads as follows:
WARNING ! - Do not open flameproof enclosure when energized. Minimum waiting time before
WARNING ! - Do not open flameproof enclosure when energized. Minimum waiting time beforeWARNING ! - Do not open flameproof enclosure when energized. Minimum waiting time before
WARNING ! - Do not open flameproof enclosure when energized. Minimum waiting time before
opening: T6 = 35 min., T5 = 10 min.
opening: T6 = 35 min., T5 = 10 min.opening: T6 = 35 min., T5 = 10 min.
opening: T6 = 35 min., T5 = 10 min.
For the OPTISONIC 7000…-Ex remote gas flow sensor no waiting time is required. The warning
message reads:
WARNING ! - Do not open when energized.
WARNING ! - Do not open when energized.WARNING ! - Do not open when energized.
WARNING ! - Do not open when energized.
1.5 Approvals
The OPTISONIC 7300 ultrasonic gas flowmeters are manufactured according to the European
directive 2014/34/EU and IECEx 02 Certification System. The flowmeters are approved for
installation and use in hazardous classified locations of zone 1 and 2 and are in accordance with
the European standards of the IEC/EN 60079 series.
The OPTISONIC 7300 ultrasonic gas flowmeter series has the following approval number(s):
KIWA 18ATEX0005 X / IECEx KIWA 18.0004X
KIWA 18ATEX0005 X / IECEx KIWA 18.0004XKIWA 18ATEX0005 X / IECEx KIWA 18.0004X
KIWA 18ATEX0005 X / IECEx KIWA 18.0004X
IEC 60079-0: 2011 :
EN 60079-0: 2012 + A11: 2013
Equipment - General Requirements
IEC 60079-1: 2014 :
EN 60079-1: 2014
Equipment protected by flameproof enclosures "d"
IEC 60079-7: 2006 :
EN 60079-7: 2007
Equipment protected by increased safety "e"
IEC 60079-11: 2011 :
EN 60079-11: 2012
Equipment protection by intrinsic safety "i"
IEC 60079-18: 2014 :
EN 60079-18: 2015
Equipment protection by encapsulation "m"
INFORMATION!
If you need the approval certificate, please download it from our website.

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1.6 OPTISONIC 7300 C/...-Ex
The OPTISONIC 7300 C/...-Ex is the compact configuration of the GFC 300 ultrasonic flow
converter and the OPTISONIC 7000 ultrasonic gas flow sensor. The gas flow sensor contains
flameproof (Ex db) gas transducers (type G7.nn or G11.nn) or partially "Ex db" with an
encapsulated front "Ex ma" (type G6.nn).
The gas flow converter is provided with non-Ex or intrinsically safe (Ex ia) inputs/outputs,
indicated by an "i" in the type name and listed as OPTISONIC 7300 C/i...-Ex.
The I/Os and mains supply connections are located in the terminal compartment, which can
either be ordered as "Ex db" or "Ex eb".
Depending on the configuration, the marking code can be:
OPTISONIC 7300 C/...-Ex
1.7 OPTISONIC 7000...-Ex
The OPTISONIC 7000...-Ex is the remote configuration of the ultrasonic gas flow sensor and has
flameproof (Ex db) constructed gas transducers (type G7.nn and G11.nn).
Optionally it can be equipped with type G6.nn gas transducers, that are partially flameproof (Ex
db) and have an encapsulated synthetic front (Ex ma).
The marking code is listed below.
The OPTISONIC 7000…-Ex remote flow sensor is always connected to the GFC 300 F/...-Ex
ultrasonic flow converter in remote design.
"Ex db" terminal compartment "Ex eb" terminal compartment
II 2 G Ex db IIC T6...T2 Gb II 2 G Ex db eb IIC T6...T2 Gb
II 2 G Ex db ma IIC T6...T4 Gb II 2 G Ex db eb ma IIC T6...T4 Gb
II 2(1) G Ex db [ia Ga] IIC T6...T2 Gb II 2(1) G Ex db eb [ia Ga] IIC T6...T2
Gb
II 2(1) G Ex db ma [ia Ga] IIC T6...T4
Gb II 2(1) G Ex db eb ma [ia Ga] IIC T6...T4 Gb
OPTISONIC 7000...-Ex
II 2 G Ex db IIC T6...T2 Gb
II 2 G Ex db ma IIC T6...T4 Gb
INFORMATION!
When thermally insulating the ultrasonic flow sensor, make sure that the temperature of the
connection box does not exceed +90
° C / +194 ° F.

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1.8 GFC 300 F/...-Ex
The GFC 300 F/...-Ex is the remote version of the ultrasonic flow converter. It has flameproof
protected connections to the flameproof gas transducers of the ultrasonic flow sensor in remote
design. The converter has non-Ex or intrinsically safe (Ex ia) I/Os, indicated by an "i" in the type
name as GFC 300 F/i-Ex.
The connection terminals of these I/Os are located in the terminal compartment, which is
configured as "Ex db" or "Ex eb".
The GFC 300 F/...-Ex ultrasonic flow converter has the following approval number(s):
KIWA 17ATEX0002 X / IECEx KIWA 17.0001X
KIWA 17ATEX0002 X / IECEx KIWA 17.0001XKIWA 17ATEX0002 X / IECEx KIWA 17.0001X
KIWA 17ATEX0002 X / IECEx KIWA 17.0001X
The marking code reads as follows:
1.9 Biogas versions
The biogas versions are low-pressure (maximum 10 bar / 145 psi) designs of the gas flowmeters
and available as compact flowmeter (OPTISONIC 7300 C/…-Ex) and as remote flow sensor
(OPTISONIC 7000…-Ex). The biogas flow sensors have additionally one or two screw-in
connections for ATEX/IECEx-approved ("Ex ia" and/or "Ex d") temperature sensor and (optional)
pressure sensor.
1.10 Ultrasonic gas transducers
The OPTISONIC 7000...-Ex gas flow sensor, which is either part of the compact gas flow meter or
available as remote design gas flow sensor, can be equipped with ultrasonic gas transducers
made of Titanium (type G7.nn) or Inconel (type 11.nn) or stainless steel/synthetic (type G6.nn)
front.
Gas transducers (type G7.nn and G11.nn) have type of protection "flameproof enclosure" (Ex db)
according to IEC/EN 60079-1. The electrical connections are established in specially designed
flameproof enclosures with a free volume far below 100 cm
3
.
Gas transducers of type G6.nn have a combination of "Ex ma" (encapsulation) and "flameproof
enclosure" (Ex db).
The ultrasonic gas transducers are approved as component and has the following approval
number(s):
FTZU 17 ATEX 0057U / IECEx FTZU 17.0029 U
FTZU 17 ATEX 0057U / IECEx FTZU 17.0029 UFTZU 17 ATEX 0057U / IECEx FTZU 17.0029 U
FTZU 17 ATEX 0057U / IECEx FTZU 17.0029 U
"Ex db" terminal compartment "Ex e" terminal compartment
II 2 G Ex db IIC T6 Gb II 2 G Ex db eb IIC T6 Gb
II 2(1) G Ex db [ia Ga] IIC T6 Gb II 2(1) G Ex db eb [ia Ga] IIC T6 Gb

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1.11 Technical data
Process medium Flammable and non-flammable gases
Protection category acc. to
IEC/EN 60529 IP 66/IP 67
Ambient temperature range
Ambient temperature rangeAmbient temperature range
Ambient temperature range
Signal converter GFC 300 F/...-Ex: -40...+65°C
1
Titanium transducers type G7.nn and
Inconel transducers type G11.nn OPTISONIC 7300 C/...-Ex: -40...+65°C
1
OPTISONIC 7000...-Ex : -40...+70°C
Stainless steel /Synthetic transducers
2
type G6.nn
Temp class T6: -40...+70°C
Temp class T5: -40...+85°C
Temp class T4: -40...+100°C
Process medium temperature range
Process medium temperature rangeProcess medium temperature range
Process medium temperature range
Titanium transducers
2
type G7.nn
OPTISONIC 7300 C/...-Ex: -50...+185°C
OPTISONIC 7000-Ex: -50...+185°C
Inconel steel transducer
type G11.nn OPTISONIC 7300 C/...-Ex: -50...+185°C
OPTISONIC 7000-Ex: -50...+185°C
Stainless steel /Synthetic transducers
2
type G6.nn
Temp class T6: -40...+70°C
Temp class T5: -40...+85°C
Temp class T4: -40...+100°C
INFORMATION!
1
Maximum ambient temperature of 65 ° C applies to aluminum MH-300-Ex converter housing.
The stainless steel version is limited to +60
° C.
2
The process medium temperature range of -50...+185 ° C applies to the flow sensor equiped
with gas transducers of type G7.nn or G11.nn. The process medium temperature range of -
40...+100
° C applies to the flow sensor equiped with gas transducers of type G6.nn The process
temperature is the temperature of the medium that surrounds the transducers. The ambient
temperature is the (air) temperature at the location where the meter is installed.

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1.12 Marking labels (examples)
See the following examples of marking labels (i.e. data stickers) of respectively
OPTISONIC 7300 C-Ex, OPTISONIC 7300 C/i-Ex ultrasonic compact flowmeter, GFC 300 F/...-Ex
ultrasonic signal converter in field design and OPTISONIC 7000...-Ex ultrasonic flow sensor.
Other marking codes are possible. The pictures that are shown are an example of a certain
configuration, which is described by the text between brackets.
1. Ex logo, marking ATEX/IECEx and ambient temperature
2. Ex specific remarks
3. Ex specific warnings
4. Protection class and Tag no.
5. PED data
6. Mains supply data and Electronic Revision no.
7. Calibration data / Size info a.o.
8. Type designation of the flowmeter & CE sign with number(s) of notified body / bodies
9. Name and address of the manufacturer
Figure 1-1: OPTISONIC 7300 C-Ex data sticker (example: 100-230 VAC)
Figure 1-2: OPTISONIC 7300 C/i-Ex data sticker (example: 100-230 VAC)

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1. Ex logo, marking ATEX/IECEx and ambient temperature
2. Ex specific remarks and warnings
3. Protection class and Tag no.
4. PED and Mains supply data
5. Calibration data / Size info and Electronic Revision no.
6. Website info and environment logo
7. Type designation of the flowmeter & CE sign with number(s) of notified body / bodies
8. Name and address of the manufacturer
1.12.1 Nameplate sensor OPTISONIC 7000...-Ex
1. Specific Ex logo, marking ATEX/IECEx and ambient temperature
2. Protection class and Explosion safety notes
3. Tag number
4. PED data
5. Size and calibration data
6. Type designation of the flowmeter and manufacturing date
7. Name and address of the manufacturer
Figure 1-3: GFC 300 F-Ex data sticker (example: 100-230 VAC)
Figure 1-4: Example: OPTISONIC 7000-Ex data sticker

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1.12.2 I/O sticker
Example of I/O sticker for modules on the inside of the terminal compartment cover
•Fieldbus IO PA on IO board 1.
•Intrinsic safety option with current out active
•Pulse/Status Out/Control in on IO board 2
Other combinations are possible. See chapter 4 "Electrical connections", for details.
Figure 1-5: I/O sticker (non-Ex ia) on cover of terminal compartment
Figure 1-6: I/O sticker (Ex ia) on cover of terminal compartment

2TEMPERATURE LIMITS
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2.1 General
Due to the influence of the process medium (gas) temperature, ultrasonic flow sensors in
remote design with type designation OPTISONIC 7000...-Ex and ultrasonic compact gas
flowmeters with type designation OPTISONIC 7300 C/...-Ex are not allocated to any fixed
temperature class. See temperature classification tables below for details.
The temperature limits apply under the following conditions:
•The device is installed and operated in accordance with the installation directions given in the
manual.
•The device is not heated up by any additional heat radiation (direct solar radiation, heat from
adjacent plant parts) so causing it to operate above the permissible ambient temperature
range.
•Insulation is not hindering free ventilation of the ultrasonic signal converter housing.
2.2 GFC 300 F/...-Ex
The GFC 300 F/...-Ex flow converter in remote design is suitable for ambient temperatures in the
range -40...+65°C / -40...+149°F with electronics unit installed in the aluminum MH 300-Ex flow
converter housing and -40...+60°C / -40...+140°F in case of the stainless steel MH 300-Ex
housing. The surface temperature always remains below +80°C / +176°F.
The flow converter in remote design is not influenced by the process temperature, because it is
installed on a distance of the remote flow sensor. It therefore has a temperature rating of T6.
2.3 OPTISONIC 7300 C/...-Ex
The OPTISONIC 7300 C/...-Ex ultrasonic compact gas flow meter is provided with the same
electronics housing as the GFC 300 F/...-Ex and therefore has the same ambient temperature
range of -40...+65°C (aluminum housing) and -40...+60°C (stainless steel). The temperature
classification table shows the relationship between the maximum process medium
temperatures at a certain maximum ambient temperature.
CAUTION!
The temperature data below only applies to the meters with ultrasonic gas transducers made of
titanium or steel (types G7.nn and G11.nn).

TEMPERATURE LIMITS 2
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Temperature classification OPTISONIC 7300 C/…-Ex with aluminum MH 300-Ex and
gas transducers type G7.nn or G11.nn.
Temperature classification OPTISONIC 7300 C/...-Ex with aluminum MH300-Ex and gas
transducers type G6.nn.
OPTISONIC 7300 C/...Ex (stainless steel housing)
The temperature limitations in the table below apply to compact flowmeters with a stainless
steel MH 300-Ex housing.
Temperature classification OPTISONIC 7300 C/…-Ex with stainless steel MH 300-Ex
and gas transducers type G7.nn or G11.nn.
Temperature classification OPTISONIC 7300 C/...-Ex with stainless steel MH300-Ex
and gas transducers type G6.nn.
Temperature class Maximum process temperature [ºC] at
T
a
d40ºC T
a
d45ºC T
a
d50ºC T
a
d55ºC T
a
d60ºC T
a
= 65ºC
T6 50 50 50 50 50 50
T5 65 65 65 65 65 65
T4 100 100 100 100 100 65
T3 165 165 165 165 115 65
T2 185 165 165 165 115 65
Temperature class Maximum process temperature [ºC] at
T
a
d40ºC T
a
d45ºC T
a
d50ºC T
a
d55ºC T
a
d60ºC T
a
= 65ºC
T6 65 65 65 65 65 65
T5 80 80 80 80 80 65
T4 100 100 100 100 100 65
Temperature class Maximum process temperature [ºC] at
T
a
d40ºC T
a
d45ºC T
a
d50ºC T
a
d55ºC T
a
= 60ºC
T6 50 50 50 50 50
T5 65 65 65 65 60
T4 100 100 100 100 60
T3 165 165 140 100 60
T2 185 165 140 100 60
Temperature class Maximum process temperature [ºC] at
T
a
d40ºC T
a
d45ºC T
a
d50ºC T
a
d55ºC T
a
= 60ºC
T6 65 65 65 65 60
T5 80 80 80 80 60
T4 100 100 100 100 60

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2.4 OPTISONIC 7000...-Ex
The OPTISONIC 7000...-Ex ultrasonic gas flow sensor is suitable for ambient temperatures
ranging from -40 to +70°C.
Temperature classification of OPTISONIC 7000…-Ex with G7.nn or G11.nn.
The following table shows the temperature classification for gas flow sensors in remote design
equipped with gas transducers of type G6.nn.
Temperature classification of OPTISONIC 7000…-Ex sensor with G6.nn.
CAUTION!
The temperature data below only applies to the meters with ultrasonic gas transducers made of
titanium or Inconel (types G7.nn and G11.nn).
Temperature class Maximum process temperature [ºC] at
T
a
d40ºC T
a
d50ºC T
a
d60ºC T
a
= 70ºC
T6 50 50 50 50
T5 65 65 65 65
T4 100 100 100 100
T3 165 165 145 125
T2 185 165 145 125
Temperature class Maximum process temperature [ºC] at T
a
= 70ºC
T6 65
T5 80
T4 100

CONNECTION OF SEPARATE SYSTEMS 3
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OPTISONIC 7300
www.krohne.com08/2018 - 4003791402 - AD EX OPTISONIC 7300 R02
3.1 General
In the case of field (remote) systems, the electrical connection between OPTISONIC 7000...-Ex
ultrasonic flow sensor and GFC 300 F/...-Ex ultrasonic signal converter is established via one
(single beam versions) signal cable of type " 2 -pole RG316 triax", or two (dual beam) signal
cable(s) . This cable consists of two triax cables (double shielding) surrounded by an additional
screen and outer insulation layer. The ends of the cables are provided with SMB connectors.
The signal cable is included with the field system.
3.2 Cable marking
The coaxial transducer cables are marked at each end by yellow tubing with a black number of
subsequently 1.1 and 1.2 for a single-beam design and numbers 1.1, 1.2, 2.1 and 2.2 for a
double-beam design. The first number represents path, 1 (single-beam) or 2 (double-beam) and
the second the position of the transducer of that path (1 or 2). The marking of the SMB counter-
plugs in the connection box is identical to that of the transducers cables (1.1, 1.2, ...).
3.3 Equipotential bonding
3.3.1 Flow sensor
The transducer circuits are galvanically isolated from earth and therefore an equipotential
bonding conductor between the ultrasonic flow sensor and the ultrasonic signal converter does
not have to be connected, but can be used if desirable.
Where screened signal cable is used, the screen should only be earthed at the flow sensor end.
In the special case of a screen being earthed at both ends of the system, a potential difference
between the sensor and converter is not permitted. Refer to IEC/EN 60079-14, Clause 12.2.2.3,
for further requirements of cable screens.
3.3.2 Signal converter
The GFC 300 F/...-Ex ultrasonic signal converter must always
must alwaysmust always
must always be incorporated within the
equipotential bonding system of the installation in the hazardous classified location. For this
purpose it must be connected to the external U-clamp screw terminal (size M5) on the mounting
support of the converter.
The separate bonding conductor must be at least 4 mm
2
(11 AWG) or 2.5 mm
2
(14 AWG), in case
it is mechanically protected (see Clause 413 of HD 384.4.41 or IEC 364-4-41). Make sure that the
core of the bonding wire is properly mounted under the U-clamp of the PE-terminal and that the
screw is tightly fixed.
The transducer circuits of the signal converter are galvanically isolated from earth, therefore an
equipotential bonding conductor between the flow sensor and the signal converter does not have
to be connected, but can be used if desired (e.g. for EMC reasons).

4ELECTRICAL CONNECTIONS
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OPTISONIC 7300
www.krohne.com 08/2018 - 4003791402 - AD EX OPTISONIC 7300 R02
4.1 General
The OPTISONIC 7300 C/...-Ex compact flowmeter must be incorporated within the equipotential
bonding system of the installation. This can be established internally by connection of the
protective earth (PE conductor of the mains supply system to the internal PE clamp, or
externally, by connecting a separate quipotential bonding conductor to the external U-clamp
terminal (size M5) at respectively the flange of the ounting support (in case of compact
instruments) or at the mounting device (for signal converters in separate version).
The display cover seals the electronics compartment of the converter housing and provides type
of protection “flameproof enclosure”(Ex db) according to IEC/EN 60079-1. The terminal
compartment is either in type of protection "increased safety" or performed as "flameproof
enclosure". The threaded joints formed by the covers and housing are a tight fit due to the
requirements for type of protection “flameproof enclosure”. Screw the covers on and off with
care and never use excessive force !
Keep the screw-threads free of dirt and well-greased (e.g. with PTFE grease). The grease will
help to prevent the threads from locking due to corrosion.
To unscrew the covers, first release the interlocking devices (one at each cover). Therefore
unscrew the M4 head screw with internal hexagon socket set using a No. 3 Allen key until the
interlocking device can be turned. After the covers are screwed back onto the housing, make
sure that the interlocking devices are properly refitted.
WARNING!
Allow the electronics to de-energize before opening the electronics compartment of the flow
converter housing. Wait at least 35 minutes for T6 and 10 minutes for T5 before opening.
Figure 4-1: Electrical connections
1 Unscrew interlocking head screw
2 Turn cover counterclockwise and remove
3 Open / close safety lid of mains supply section
4 Mains supply & signal / data terminals