WIKA TR12 Series Operating instructions

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DE
FR
ES
Additional operating instructions
Zusatz-Betriebsanleitung
Informations supplémentaires
Información adicional
TÜV 10 ATEX 555793X
IECEx TUN 10.0002X
Additional operating instructions for hazardous areas (Ex i)
Models TR12 and TC12
Zusatz-Betriebsaneleitung für explosionsgefährdete Bereiche (Ex i)
Typen TR12 und TC12
Mode d’emploi complémentaires concernant les zones explosives
(Ex i), types TR12 et TC12
Manual de instrucciones adicional para zonas potencialmente
explosivas (Ex i) Modelos TR12 y TC12
Models TR12-A, TC12-A Models TR12-B, TC12-B Models TR12-M, TC12-M

EN
DE
FR
ES
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WIKA additional information TR12/TC12, intrinsically safe designs (Ex i)
Additional operating instructions models TR12, TC12
(Ex i)
Page
3 - 24
Zusatz-Betriebsaneleitung Typen TR12, TC12 (Ex i)
Seite
25 - 46
Mode d’emploi complémentaires types TR12, TC12
(Ex i)
Page
47 - 68
Manual de instrucciones adicional para los modelos
TR12, TC12 (Ex i)
Página
69 - 89
© 12/2018 WIKA Alexander Wiegand SE & Co. KG
All rights reserved. / Alle Rechte vorbehalten.
WIKA®is a registered trademark in various countries.
WIKA®ist eine geschützte Marke in verschiedenen Ländern.
Prior to starting any work, read the operating instructions!
Keep for later use!
Vor Beginn aller Arbeiten Betriebsanleitung lesen!
Zum späteren Gebrauch aufbewahren!
Lire le mode d'emploi avant de commencer toute opération !
A conserver pour une utilisation ultérieure !
¡Leer el manual de instrucciones antes de comenzar cualquier trabajo!
¡Guardar el manual para una eventual consulta!

1. Ex marking 4
2. Safety 6
3. Commissioning, operation 8
4. Special conditions of use (X conditions) 18
5. Calculation examples for self-heating at the thermowell tip 20
Annex: EU declaration of conformity 23
Declarations of conformity can be found online at www.wika.com.
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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 3
Contents
Contents

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)4
1. Ex marking
DANGER!
Danger to life due to loss of explosion protection
Non-observance of these instructions and their contents may result in the
loss of explosion protection.
▶
Observe the safety instructions in this chapter and further explosion
instructions in these operating instructions.
▶
Follow the requirements of the ATEX directive.
▶
Observe the information given in the applicable type examination certifica-
te and the relevant regulations for installation and use in hazardous areas
(e.g. IEC 60079-11, IEC 60079-10 and IEC 60079-14).
Check whether the classification is suitable for the application. Observe the relevant natio-
nal regulations.
ATEX IECEx
II 1G Ex ia IIC T1 ...T6 Ga
II 1/2G Ex ia IIC T1 ...T6 Ga/Gb
II 2G Ex ia IIC T1 ...T6 Gb
II 1D Ex ia IIIC T1 ... T6 Da
II 1/2D Ex ia IIIC T1 ...T6 Da/Db
II 2D Ex ia IIIC T1 ... T6 Db
1. Ex marking
Supplementary documentation:
▶
This additional information for hazardous areas applies in conjunction with the operating
instructions “Resistance thermometer TR12 and thermocouple TC12” (article number
14064370).

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 5
For applications without transmitters (digital indicators) requiring instruments of equipment
group II (potentially explosive gas atmospheres), the following temperature class classifica-
tion and ambient temperature ranges apply:
Table 1
Marking Tempe-
rature
class
Ambient tempe-
rature range (Ta)
Max. surface
temperature
(Tmax) at the probe or
thermowell tip
ATEX IECEx
II 1G Ex ia IIC T1 ... T6 Ga
II 1/2G Ex ia IIC T1 ... T6
Ga/Gb
II 2G Ex ia IIC T1 ... T6 Gb
T1 ...T6 (-50) 1) -40 ... +80 °C
[(-58) 1)-40 ... +176 °F]
TM(medium temperature) +
self-heating
For this, the special condi-
tions must be observed (see
chapter 4 „Besondere Bedin-
gungen für die Verwendung
(X-Conditions)“).
For applications requiring instruments of equipment group II (potentially explosive dust
atmospheres), the following surface temperatures and ambient temperature ranges apply:
Table 2
Marking Power
Pi
Ambient tempe-
rature range (Ta)
Max. surface
temperature
(Tmax) at the probe or ther-
mowell tip
ATEX IECEx
II 1D Ex ia IIIC T1 ... T6 Da
II 1/2D Ex ia IIIC T1 ...T6 Da/Db
II 2D Ex ia IIIC T1 ... T6 Db
750 mW (-50) 1) -40 ... +40 °C
[(-58) 1)-40 ... +104 °F] TM(medium temperature) +
self-heating
For this, the special conditions
must be observed (see chapter 4
„Besondere Bedingungen für die
Verwendung (X-Conditions)“).
II 1D Ex ia IIIC T1 ... T6 Da
II 1/2D Ex ia IIIC T1 ...T6 Da/Db
II 2D Ex ia IIIC T1 ... T6 Db
650 mW (-50) 1) -40 ... +70 °C
[(-58) 1)-40 ... +158 °F]
II 1D Ex ia IIIC T1 ... T6 Da
II 1/2D Ex ia IIIC T1 ...T6 Da/Db
II 2D Ex ia IIIC T1 ... T6 Db
550 mW (-50) 1) -40 ... +80 °C
[(-58) 1)-40 ... +176 °F]
1) The values in brackets apply to special versions.These probes are manufactured using special potting compounds. Moreo-
ver, they feature cases made of stainless steel and cable glands for low-temperature ranges.
When there is a built-in transmitter and/or a digital indicator, the special conditions from
the type examination certificate (see chapter 4 „Special conditions of use (X conditions)“)
apply.
1. Ex marking

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)6
Use in methane atmospheres
Due to the higher minimum ignition current of methane, the instruments can also be used
where methane causes a potentially explosive gas atmosphere.The instrument can optio-
nally be marked with IIC + CH4.
For applications that require EPL Gb or Db, the instruments marked with “ia” can also be
used in type “ib” measuring circuits.
2. Safety
2.1 Explanation of symbols
DANGER!
... indicates a potentially dangerous situation in the hazardous area that can
result in serious injury or death, if not avoided.
2.2 Intended use
The thermometers described here are suitable for temperature measurement in hazardous
areas.
The non-observance of the instructions for use in hazardous areas can lead to the loss
of the explosion protection. Adhere to the following limit values and instructions (see data
sheet).
2.3 Responsibility of the operator
The responsibility for classification of zones lies with the plant manager and not the
manufacturer/supplier of the equipment.
2.4 Personnel qualification
The skilled electrical personnel must have knowledge of ignition protection types, regulati-
ons and provisions for equipment in hazardous areas.
1. Ex marking / 2. Safety

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 7
2.5 Labelling, safety marks
Product label (example)
TR12-M-IIBZ
1 x Pt100 / A / 3 (F) -50 ... +500 °C
Um = DC 30 V / Pm = 2 W
BVS 07 ATEX E 071 X
IECEx BVS 11.0042X
II 2 G Ex db IIC T* Gb
EN 60751
0158
WIKA Alexander Wiegand SE & Co.KG, D-63911 Klingenberg
Made in Germany 2013 WARNING: DO NOT OPEN WHILE ENERGIZED!
11012345
TR12-B-IDBZ
1 x Pt100 / A / 3 (F) -50 ... +500 °C
Um = DC 30 V / Pm = 2 W
BVS 07 ATEX E 071 X
IECEx BVS 11.0042X
II 2 G Ex db IIC T* Gb
EN 60751
0158
WIKA Alexander Wiegand SE & Co.KG, D-63911 Klingenberg
Made in Germany 2013 WARNING: DO NOT OPEN WHILE ENERGIZED!
11012345
TC12-B-IDBZ
1 x Typ K / 1 / . 0 ... +600 °C
Um = DC 30 V / Pm = 2 W
BVS 07 ATEX E 071 X
IECEx BVS 11.0042X
II 2 G Ex db IIC T* Gb
EN 60584-1
0158
WIKA Alexander Wiegand SE & Co.KG, D-63911 Klingenberg
Made in Germany 2013 WARNING: DO NOT OPEN WHILE ENERGIZED!
11012345
TR12-M-IDK*
1 x Pt100 / A / 3 (F) -50 ... +500 °C
Um = DC 30 V / Pm = 2 W
BVS 07 ATEX E 071 X
IECEx BVS 11.0042X
II 2 G Ex db IIC T* Gb
EN 60751
0158
WIKA Alexander Wiegand SE & Co.KG, D-63911 Klingenberg
Made in Germany 2013 WARNING: DO NOT OPEN WHILE ENERGIZED!
11012345



 

Model
A = measuring insert
B = process thermometer
M = basic module
Serial number
Approval-related data
Year of manufacture

■
Information on version (measuring element, measuring range...)
Sensor in accordance with standard (resistance thermometer)
- F = Thin-film measuring resistor
- W = Wire-wound measuring resistor
Sensor in accordance with standard (thermocouple)
- ungrounded = ungrounded welded
- grounded = welded to the sheath (grounded)
- quasi grounded = The thermometer is, due to its low insulation clearances between resis-
tance sensor and sheath, to be considered as grounded.
■
Transmitter model (only for design with transmitter)
Before mounting and commissioning the instrument, ensure you
read the operating instructions!
2. Safety

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)8
3. Commissioning, operation
DANGER!
Danger to life from explosion
By using a measuring insert without a suitable connection head (case), an
explosion risk occurs which can cause fatalities.
▶
Only use the measuring insert in the connection head designed for it.
DANGER!
Danger to life from missing instrument grounding
With missing or incorrect grounding, there exists a risk of dangerous voltages
(leading to, for example, mechanical damage, electrostatic charge or induc-
tion).
▶
Ground thermometer!
Observe the special conditions (see chapter 4 „Special conditions of use (X conditions)“,
point 2).
3.1 Safety-related instructions for the different variants
TR12-B, TC12-B
Variant 1
TR12-B, TC12-B
Variant 2
TR12-B, TC12-B
Variant 3
Thread
TR12-M, TC12-M
Module
Thread
Thread Thread Thread
Legend:
Connection head
Neck tube
Connection to thermowell/
protection tube
Measuring insert
Terminal block
Transmitter (option)
Field transmitter
14039769.01
T4
T3
T1
Tundefined
3. Commissioning, operation
T4: (-50) -40 °C [(-58) -40 °F] < Ta< +80 °C [+176 °F]
T3: (-50) -40 °C [(-58) -40 °F] < Ta< +150 °C [+302 °F]
T1: (-50) -40 °C [(-58) -40 °F] < Ta< +300 °C [+572 °F]

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 9
3.1.1 Variant 1
The thermometer is fitted to a certified enclosure in which the terminal block is fitted. If the
thermometer is marked with II 2G Ex ia IIC T1 ... T6 Gb, then it is designed for use in zone
1. If the thermometer is marked with II 1/2G Ex ia IIC T1 ...T6 Ga/Gb, then it is designed for
use with a thermowell at the partition to zone 0.
▶
ATEX/IECEx case or connection head (with connection terminals, without transmitter)
Evaluation of the resistance or the thermoelectric voltage by means of an electronic
assembly outside of the hazardous area.
Use in zone 1, marking II 2G Ex ia IIC T1 ... T6 Gb
The case or the connection head is in zone 1 (or zone 2).The sensor is located in zone 1.
Use at the partition to zone 0, marking II 1/2G Ex ia IIC T1 ... T6 Ga/Gb
The case or the connection head is in zone 1 (or zone 2).The sensor is within a thermowell
(min. wall thickness 1 mm) which extends into zone 0 via a process connection.
Powering with Ex ia electric circuit fulfils these conditions.The responsibility rests with the
operator.
The permissible ambient temperatures for third-party products can be seen from the
relevant approvals or data sheets.
A heating in the connection head does not occur with variant 1. However, an impermissible
heat backflow from the process which can exceed the operating temperature of the case
or the temperature class, must be prevented through suitable heat insulation or a suitably
long neck tube.
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)10
3.1.2 Variant 2
The thermometer is tted to certied enclosures, which have an electronic assembly built
into it. If the thermometer is marked with II 2G Ex ia IIC T1 ...T6 Gb, then it is designed for
use in zone 1. If the thermometer is marked with II 1/2G Ex ia IIC T1 ...T6 Ga/Gb, then it is
designed for use with a thermowell at the partition to zone 0.
▶
ATEX/IECEx Ex ia case or connection head with built-in head-mounted transmitter
The evaluation is made via a current (4 … 20 mA), voltage (0 … 10 V) or fieldbus signal,
which is generated from a head-mounted transmitter.
Use in zone 1, marking II 2G Ex ia IIC T1 ... T6 Gb
The case or the connection head is in zone 1 (or zone 2).The sensor is located in zone 1.
Use at the partition to zone 0, marking II 1/2G Ex ia IIC T1 ... T6 Ga/Gb
The case or the connection head is in zone 1 (or zone 2).The sensor is within a thermowell
(min. wall thickness 1 mm) which extends into zone 0 via a process connection.
The thermometer should be operated with a power-limiting circuit.
Pmax: 1.5 W
Umax: 30 V
Powering with Ex ia electric circuit fulfils these conditions.The responsibility rests with the
operator.
A heating in the connection head can occur with variant 2 through faulty electronics.The
permissible ambient temperatures depend on the case used and any additionally fitted
head-mounted transmitter.
However, an impermissible heat backflow from the process which can exceed the opera-
ting temperature of the case or the temperature class, must be prevented through suitable
heat insulation or a suitably long neck tube.
3.1.3 Variant 3
The thermometer is fitted to certified equipment (transmitter).The thermometer is marked
with II 2G Ex ia IIC Tx Gb and is designed for use in zone 1 with a thermowell. For any
potential usage at the partition to zone 0 with a thermowell, the approvals and conditions of
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 11
the relevant transmitters must be considered.
▶
ATEX/IECEx-Ex i-certified temperature transmitters
The evaluation is carried out via a current (4 … 20 mA), voltage (0 … 10 V) or fieldbus
signal, which is generated by an ATEX/IECEx-Ex i-certified temperature transmitter.
Use in zone 1, marking II 2G Ex ia IIC Gb
The case or the connection head is in zone 1 (or zone 2).The sensor is located in zone 1.
The main marking for models TR12-B and TC12-B are found on the certified connection
housing or Ex i field transmitter.
The TR12-M and TC12-M modules are marked through a foil plate on the neck tube.
For a possible use at the partition to zone 0 with a thermowell, the approvals and condi-
tions of the relevant Ex i field transmitters must be followed.
3.1.4 Use in methane atmospheres
As a result of the higher Minimum Experimental Safe Gap (MESG) and Minimum Ignition
Current (MIC) of methane, the instruments can also be used in potentially explosive gas
atmospheres caused by this.
Ui= see third-party transmitter approval
Ii= see third-party transmitter approval
Pi= see third-party transmitter approval
Li= see third-party transmitter approval
Ci= see third-party transmitter approval
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)12
3.2 Electrical mounting
Using a transmitter/digital indicator (option):
Observe the contents of the operating instructions for the transmitter/digital indicator (see
scope of delivery).
Built-in transmitters/digital indicators have their own EC-type examination certificate.The
permissible ambient temperature ranges of built-in transmitters can be taken from the
corresponding transmitter approval.
Observe the special conditions (see chapter 4 „Special conditions of use (X conditions)“,
point 3).
Electrical connection values
■
Electrical data without built-in transmitter or digital indicator
Parameters Instrument group II
Potentially explosive gas atmosphere 1)
Voltage UiDC 30 V
Current li550 mA
Power Pi(at the sensor) 1.5 W 2) 3)
Effective internal capacitance, Ci, of
standard measuring inserts in accordance
with DIN 43735
Negligible
Effective internal inductance, Li, of
standard measuring inserts in accordance
with DIN 43735
Negligible
1) Use in methane atmospheres
Owing to the higher minimum ignition energy of methane, the instruments can also be used where methane causes a
potentially explosive gas atmosphere.
2) The permissible power to the sensor depends on the temperature of the medium TM, the temperature class and the
thermal resistance Rth, but shall not be more than 1.5 W.
Calculation examples see chapter 5 „Calculation examples for self-heating at the thermowell tip“.
3) The permissible power to the sensor depends on the temperature of the medium TM, the maximum allowed surface
temperature and the thermal resistance Rth, but shall not be more than the values from “Table 2” (column 2), chapter
1 „Ex marking“.
■
Electrical data with built-in transmitter or digital indicator
Ui= depending on the transmitter/digital indicator
Ii= depending on the transmitter/digital indicator
Pi= in the case: depending on the transmitter/digital indicator
Ci= depending on the transmitter/digital indicator
Li= depending on the transmitter/digital indicator
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 13
■
Electrical data with built-in transmitter in accordance with the FISCO model
The transmitters/digital indicators used for the application range in accordance with the
FISCO model are considered FISCO field instruments.The requirements in accordance
with IEC/EN 60079-27, and the connection conditions of the approvals in accordance
with FISCO, apply.
3.3 Temperature class classification, ambient temperatures
The permissible ambient temperatures depend on the temperature class, the cases used
and the optional built-in transmitter and/or digital indicator.
When a thermometer is connected to a transmitter and/or a digital indicator, the lowest
value of either the ambient temperature limits or the highest temperature class will apply.
The lower temperature limit is -40 °C; and -50 °C for special versions.
Where there are neither transmitters nor digital indicators mounted within the case, there
will also be no additional warming.With a built-in transmitter (optionally with digital indica-
tor), heating caused by operating the transmitter or digital indicator may occur.
For applications without transmitters (digital indicators) requiring instruments of equipment
group II (potentially explosive gas atmospheres), the following temperature class classifica-
tion and ambient temperature ranges apply:
Temperature class Ambient temperature range (Ta)
T1 ...T6 (-50) -40 … +80 °C [(-58) -40 ... +176 °F]
The permissible ambient temperatures and surface temperatures for third-party products
can be seen from the relevant approvals and/or data sheets and must be observed.
Example
For instruments fitted with a transmitter and DIH50 digital indicator, for example, the
following limit for temperature class classification applies:
Temperature class Ambient temperature range (Ta)
T6 -40 … +55 °C [-40 ... 131 °F]
The permissible ambient temperatures and surface temperatures for third-party products
can be seen from the relevant approvals and/or data sheets and must be observed.
The values in brackets apply to special versions.These probes are manufactured using
special potting compounds. Moreover, they feature connection heads made of stainless
steel and cable glands for low-temperature ranges.
According to approval, these thermometers are suitable for the temperature classes T1 ...
T6.This applies for instruments with or without built-in transmitters and/or digital indica-
tors. Make sure the maximal ambient temperature for the safe use of the instrument is not
exceeded.
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)14
3.4 Temperature carry-over from the process
Prevent any heat backflow from the process!
Observe the special conditions (see chapter 4 „Special conditions of use (X conditions)“,
point 4).
3.5 Overview of the temperature zones
FF-00147.00
Tx12 Tx12
Option: with built-in transmit-
ter e.g.T32
Tx12-A Tx12-A
T3
T3
Process connection Process connection
1) Permissible temperatures at
T1: (-50) -40 °C [(-58) -40 °F] < Ta< +300 °C [572 °F]
T3: (-50) -40 °C [(-58) -40 °F] < Ta< +150 °C [302 °F]
T4: (-50) -40 °C [(-58) -40 °F] < Ta< +80 °C [176 °F]
T4Transmitter: (-50) -40 °C [(-58) -40 °F] < Ta< +80 °C [176 °F]
1) Temperature zone undefined
T4 T4Transmitter
T1 T1
1)
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 15
3.6 Mounting examples
3.6.1 Possible installation methods with the marking II 1G Ex ia IIC T6 Ga or
II 1D Ex ia IIIC T65 °C Da
The probe together with case or connection head is located in zone 0 (zone 20). An Ex ia
type current circuit must be used. Connection heads/cases made of aluminium are usually
not permitted in zone 0. At this position, WIKA recommends connection heads/cases made
of stainless steel.
Protective measures for applications that require EPL Ga or Da:
For the case where a light metal case is used in zone 0, the following protective measures
apply:
Operationally based friction or impacts between light metal instrument components or their
alloys (e.g. aluminium, magnesium, titanium or zirconium) and instrument components
from iron/steel, are not permitted. Operationally based friction or impacts between light
metals are permitted.
Observe the special conditions (see chapter 4 „Special conditions of use (X conditions)“,
points 5 and 7).
Zones 0, 1, 2 or zones 20, 21, 22
Hazardous area Non-hazardous area
Process
connection
Connection
head/Field case
Tx12-B
Tx12-A
Associated
electr. equipment
Intrinsically
safe supply or
suitable barrier
from 14094977.00
Tx12-B
Option:
with built-in
transmitter
e.g.T32
Compression
fitting
Intrinsically
safe supply or
suitable barrier
Tx12-A
Thermowell
TWxx
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)16
3.6.2 Possible installation methods with the marking II 1/2G Ex ia IIC T1 ... T6 Ga/
Gb or II 1/2D Ex ia IIIC T65 ... T125 °C Da/Db
The probe or thermowell tip protrudes into zone 0.The case or connection head is in zone
1 (zone 21) or zone 2 (zone 22). It is sufficient to use an Ex ib type circuit.
Zone separation is guaranteed if sufficiently sealed (IP66 or IP67) process connections are
used.
Examples of suitable process connections include gas-tight standardised industrial
flanges, threaded connections or pipe connections.
The process connections, thermowells or cases used must be designed such that they
withstand all influencing variables resulting from the process, such as temperature, flow
forces, pressure, corrosion, vibration and impacts.
Zones 1, 2 or
zones 21, 22
Zones 0, 1, 2 or
zones 20, 21, 22
Hazardous area Non-hazardous area
Process
connection
Connection
head/Field case
Tx12-B
Tx12-A
Associated
electr. equipment
Intrinsically
safe supply or
suitable barrier
from 14094977.00
Tx12-B
Option:
with built-in
transmitter
e.g.T32
Compression
fitting
Intrinsically
safe supply or
suitable barrier
Tx12-A
Thermowell
TWxx
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 17
3.6.3 Possible installation methods with the marking II 2G Ex ia IIC T1 ... T6 Gb or II
2D Ex ia IIIC T65 °C ... T125 °C Db
3.7 Partition for use in zone 0 or zone 1/2 or separation between hazardous area
and non-hazardous area
If the wall thickness is less than 1 mm, the instrument must also be marked with an “X” or
a safety instruction in accordance with 29.2 of IEC/EN 60079-0, with the specific condition
that for safe use it must not be subjected to ambient stresses that may have an adverse
effect on the partition. If the partition is continuously subjected to vibrations (e.g. vibrating
membranes), its fatigue limit at the maximum amplitude must be stated in the documentati-
on (see section 4.2.5.2, IEC/EN 60079-26).
Observe the special conditions (see chapter 4 „Special conditions of use (X conditions)“,
point 5).
Alternatively, a thermowell of suitable minimum wall thickness may be used by the custo-
mer. For this, the special conditions must be observed (see chapter 4 „Special conditions
of use (X conditions)“, point 6).
Zones 1, 2 or zones 21, 22
Hazardous area Non-hazardous area
Process
connection
Connection
head/Field case
Tx12-B
Tx12-A
Associated
electr. equipment
Intrinsically
safe supply or
suitable barrier
from 14094977.00
Tx12-B
Option:
with built-in
transmitter
e.g.T32
Compression
fitting
Intrinsically
safe supply or
suitable barrier
Tx12-A
Thermowell
TWxx
3. Commissioning, operation

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)18
4. Special conditions of use (X conditions)
1)
Versions with Ø <3 mm or “grounded” versions are non-compliant with section 6.3.13
of IEC/EN 60079-11.Therefore, from a safety-relevant point of view, these intrinsically
safe circuits must be considered galvanically connected (“quasi grounded” ) to the
earth potential, which is why equipotential bonding must be secured for the entire instal-
lation of the intrinsically safe circuits. In addition, for the connection, separate conditions
in accordance with IEC/EN 60079-14 must be observed.
2) Electrostatic charges must be avoided in instruments, that due to their design, do not
conform to the electrostatic requirements in accordance with IEC/EN 60079-0 and IEC/
EN 60079-26.
3) The transmitters/digital indicators used must have their own EC-type examination certi-
ficate in accordance with IEC/EN.The installation conditions, the electrical connection
values, the temperature class respectively the maximum surface temperatures of devices
for the use in explosive dust atmospheres and the permissible ambient temperature shall
be taken from the corresponding EC-type examination certificate and shall be conside-
red.
4) Heat backflow from the process, that exceeds the permissible ambient temperature of
the transmitter, digital indicator or case must not be allowed to occur. It must be preven-
ted by installing suitable heat insulation or a neck tube of suitable length.
5) If the wall thickness is below 1 mm, the instruments must not be subjected to ambient
stresses that may have an adverse effect on the partition. Alternatively, a thermowell of
suitable minimum wall thickness may be used.
6) Using a thermowell/neck tube the instruments shall be constructed in a way that allows
an installation that results in a sufficiently tight joint (IP66 or IP67) or a flameproof joint
(IEC/EN 60079-1) towards the less hazardous area.
7) Not relevant for this instrument (see X conditions in EC-type examination certificate)
8) When cases are used, they must either have their own suitable EC-type examination
certificate or comply with the minimum requirements.
IP protection: at least IP 20 (at least IP6x for dust), applies to all cases
Light metal casings must comply with the relevant sections of the applicable standards.
In addition, non-metal cases or powder-coated cases must meet the electrostatic requi-
rements of the applicable standards or have an appropriate warning label.
9) Accessible parts of ungrounded metal enclosures and accessible parts of metal enclo-
sures that are grounded but do not conform to section 6.5 of IEC/EN 60079-11 shall
conform to section 7.5 of IEC/EN 60079-0 or be marked with an appropriate warning
label.
4. Special conditions of use (X conditions)

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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i) 19
10) If it is not possible to specify the ambient temperature range on the labelling of the
instrument because the instrument is a small device in accordance with section 29.10 of
IEC/EN 60079-0, then the ambient temperature range shall be specified in the operating
instructions supplied with the instrument. If the instrument is not a small instrument in
accordance with section 29.10 of IEC/EN 60079-0, the labelling of the instrument must
also contain a reference to the operating instructions supplied.
Protective measures for applications that require EPL Ga or Da:
Operationally based friction or impacts between light metal instrument components or their
alloys (e.g. aluminium, magnesium, titanium or zirconium) and instrument components
from iron/steel, are not permitted. Operationally based friction or impacts between light
metals are permitted.
4. Special conditions of use (X conditions)

EN
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WIKA additional operating instructions TR12/TC12, intrinsically safe designs (Ex i)20
5. Calculation examples for self-heating at the ...
5. Calculation examples for self-heating at the thermowell tip
The self-heating at the thermowell tip depends upon the sensor type (TC/RTD), the
measuring insert diameter and the thermowell design.The table below shows the possible
combinations.The heating at the sensor tip of the bare measuring insert is clearly higher;
the representation of these values was omitted on the grounds of the required assembly
with a thermowell.
The table shows that thermocouples generate much less self-heating than resistance
thermometers.
Thermal resistance [Rth in K/W]
Sensor type RTD TC
Measuring insert diameter 3.0 -
< 6.0
6.0 -
≤8.0
3.0 -
< 6.0
6.0 -
≤8.0
With protection tube
(straight and tapered), e.g.TW35, TW40 etc.
60 37 11 2.5
With thermowell - bar stock material
(straight and tapered), e.g.TW10, TW15, TW20, TW25,
TW30 etc.
22 16 4 1
Built into a blind bore
(minimum wall thickness 5 mm [0.197 in])
22 16 4 1
5.1 Example calculation for variant 2 with TC sensor
Under the same conditions it gives a lower value for the self-heating, since the supplied
power is not only converted at the probe tip, but rather over the entire length of the measu-
ring insert.
Thermal resistance [Rth in K/W] from table = 3 K/W
Self-heating: 0.8 W * 3 K/W = 2.4 K
Tmax = TM+ self-heating: 150 °C [302 °F] + 2.4 °C [36 °F] = 152.4 °C [306 °F]
As a safety margin for type-tested instruments (for T6 to T3), an additional 5 °C [41 °F]
must be subtracted from the 200 °C [392 °F]; hence 195 °C [383 °F] would be permissible.
This means that in this case temperature class T3 is not exceeded.
In this example it is clear that the self-heating here is almost negligible.