Read this instruction carefully prior to installation and/or use. Pay attention particularly to all advises and safety instructions to prevent injuries. Bühler Technologies can not be held responsible for misusing
the product or unreliable function due to unauthorised modifications.
All rights reserved. Bühler Technologies GmbH 2018
1.5Scope of Delivery.................................................................................................................................................................................................. 3
3 Transport and storage ..................................................................................................................................................................................................6
4 Installation and connection........................................................................................................................................................................................ 7
5 Operation and control ................................................................................................................................................................................................ 10
6 Cleaning and Maintenance........................................................................................................................................................................................12
7 Service and repair..........................................................................................................................................................................................................13
7.1Spare parts and accessories ............................................................................................................................................................................13
9.1Technical Data .....................................................................................................................................................................................................15
The level switch is used to monitor levels and temperatures inside a tank. The measuring tube is inside the tank during the process.
According to IEC/EN60079-11, NT61-Z0-Atex series level switches are simple electrical apparatuses without separate voltage
source intended for installation inside the tank.
When used in explosive areas this type may only be operated on intrinsically-safe circuits. When using intrinsically-safe connections they can be installed in Zone 1 explosive areas and the level or temperature be monitored in a Zone 0 environment. The intrinsically-safe power supply must be suitable for the zone. The limits inside these operating instructions must be observed.
Never the use level switches in highly flammable or corrosive liquids. The medium must not contain particles, particularly
metallic particles, to prevent deposits on the float or between the float and switching tube.
Before installing the level switch, verify the listed technical data meet the application parameters. Also observe the applicable
requirements of IEC/EN60079-14.
Further check if all contents are complete.
Please note the specific values of the level switch when connecting and the correct version when ordering spare parts.
The explosion protection markings on the level switches are:
II 1G Ex ia IIC T4 Ga
II 1D Ex ia IIIC T70°C Da
1.2 Functionality
1.2.1 Fill level monitoring
The measuring tube is located inside the tank. The level contacts (bistable reed contacts) are located inside the measuring tube.
These are activated by a magnet inside the level switch float. This can switch signals used to display the fill level.
The contacts clip onto a perforated rail spaced as specified in the purchase order and cannot be moved.
1.2.2 Temperature monitor
The temperature of a fluid is monitored via bimetal disc thermostat inside the level switch tube. When a set temperature is
reached, a bimetal snap disk inside the thermostat is triggered, which opens or closes an electrical contact. A Pt100 temperature
sensor can optionally be used in place of the bimetal thermostat.
Please note the technical data in the appendix.
1.3 Type plate
Example:
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Type designation
Version
Z0
Zone0
Plug connection
M3
M12
2M12
Length in mm (max. 1500)
280
370
500
variable (please specify)
Level measurement
1-4
Number of contacts
K
W
= NC/NO
= Change-over contact
Temperature
TK50NC
TK60NC
TK70NC
TK50NO
TK60NO
TK70NO
= 50 °C NC
= 60 °C NC
= 70 °C NC
Pt100
Temperature sensor
Stilling tube
SSR
NT 61
Level contact
Options
-
XX
XX
ATEX
XX
X X
= 50 °C NO
= 60 °C NO
= 70 °C NO
XX
XX
-
-
-
-
-
-
1.4 Model key
1.5 Scope of Delivery
– 1 x Level switch
– 1 x Rubberised cork seal D1=90 x D2=60x4, item no.: 9009113
– 6 x Hexagon screw, item no.: 9011606
– 6 x Disc DIN125-A5.3, item no.: 9012234
– Product documentation
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DANGER
WARNING
CAUTION
NOTICE
2 Safety instructions
2.1 Important advice
This unit may only be used if:
– The product is being used under the conditions described in the operating- and system instructions, used according to the
nameplate and for applications for which it is intended. Any unauthorized modifications of the device will void the warranty
provided by Bühler Technologies GmbH,
– The specifications and markings in the type plate are observed,
– The specified limits are observed,
– The equipment is operated on intrinsically-safe circuits, see chapter “Intrinsically-Safe Connection”,
– The protective element is installed outside the explosive area,
– No equipment functions exceed the limits,
– Monitoring equipment / protection devices are connected correctly,
– Service and repair work not described in these instructions are performed by Bühler Technologies GmbH,
– Genuine replacement parts are used.
Regulations IEC/EN60079-14 and IEC/EN60079-17 must be observed when erecting electrical systems in explosive areas.
Additional national regulations pertaining to initial operation, operation, maintenance, repairs and disposal must be observed.
These operating instructions are a part of the equipment. The manufacturer reserves the right to change performance-, specification- or technical data without prior notice. Please keep these instructions for future reference.
Signal words for warnings
Signal word for an imminent danger with high risk, resulting in severe injuries or death if not avoided.
Signal word for a hazardous situation with medium risk, possibly resulting in severe injuries or death if not
avoided.
Signal word for a hazardous situation with low risk, resulting in damaged to the device or the property or
minor or medium injuries if not avoided.
Signal word for important information to the product.
Warning signs
These instructions use the following warning signs:
Warns of a general hazardGeneral information
Warns of voltageUnplug from mains
Warns not to inhale toxic gassesWear respiratory equipment
Warns of corrosive liquidsWear a safety mask
Warns of explosive areasWear gloves
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2.2 General hazard warnings
The equipment must be installed by a professional familiar with the safety requirements and risks.
Be sure to observe the safety regulations and generally applicable rules of technology relevant for the installation site. Prevent
malfunctions and avoid personal injuries and property damage.
The operator of the system must ensure:
– Safety notices and operating instructions are available and observed,
– The respective national accident prevention regulations are observed,
– The permissible data and operational conditions are maintained,
– Safety guards are used and mandatory maintenance is performed,
– Legal regulations are observed during disposal.
Maintenance, Repair
Please note during maintenance and repairs:
– Repairs to the unit must be performed by Bühler authorised personnel.
– Only perform conversion-, maintenance or installation work described in these operating and installation instructions.
– Always use genuine spare parts.
Always observe the applicable safety and operating regulations in the respective country of use when performing any type of
maintenance.
The method for cleaning the devices must be adapted to the IP protection class of the devices. Do not use cleaners which could
damage the device materials.
DANGERToxic, acidic gases/liquids
Protect yourself from toxic, corrosive gasses/liquids when performing any type of work.
Wear appropriate protective equipment.
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3 Transport and storage
Only transport the product inside the original packaging or a suitable alternative.
The equipment must be protected from moisture and heat when not in use. It must be stored in a covered, dry, dust-free room
at room temperature.
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4 Installation and connection
4.1 Installation
Please note before installing the level switch!
After transport and delivery of the level switch, the switching status of the bistable contacts may be different than required for
proper operation.
Therefore slide the float for the level switch along the level switch tube from below immediately before installation.
This ensures all built-in bistable contacts have a clearly defined switching status (NC or NO).
The level switch (transmitter) comes fully assembled and can be mounted to the tank by flange, included screws and seals.
Please be sure the float can move freely and to leave enough space between the tank wall and add-ons.
After removing the float, where applicable, be sure the magnet inside the float is above the fluid level. This can easily be verified
with a piece of iron to determine the magnet position inside the float.
4.2 Electrical connections
4.2.1 PA connection (potential equalisation)
CAUTIONElectrostatic charge
Level switch housings and stilling tubes must be connected to the tank via external PA
connection!
Ensure the level switch is adequately earthed (minimum conductor cross-section 4mm2).
Particularly also observe the requirements of IEC/EN 60079-14.
The level switch has an external PA connection. This is identified by the decal shown on the left. The connection uses an
M5 thread. The PA cable for potential equalisation between the level switch or stilling tube (drawing B) and the tank is
not included with this version and must be supplied and installed by the customer.
Layout of the PA connection:
1 Screw4 PA cable (to be installed by the customer)
2 Serrated washer5 Washer
3 Washer
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2
3
4
5
6
1
2
3
1
PA connection examples:
Drawing A
1 Level switch4 PA cable
2 PA decals5 PA connection on the tank
3 PA connection on the level switch6 Tank
Drawing B
1 Stilling tube3 PA connection
2 PA cable
4.2.2 Intrinsically-safe connection
According to IEC/EN60079-11 the components for level and temperature monitoring are simple electrical equipment and to be
considered purely ohmic circuits. They may only be operated with an type-tested controller with an intrinsically-safe circuit.
CAUTIONExplosion hazard due to prohibited electrical connection data
Prohibited electrical connection data can cause an explosive gas mixture to ignite.
In areas with explosive gas atmospheres the level switch may only be operated with an
intrinsically-safe power supply. The power supply must be suitable for the respective
zone. The limits specified in these operating instructions must be observed and must not
exceeded, even with two separate intrinsically-safe power supplies.
Ensure the limits will not be exceeded, even in the event of a fault, e.g. accidental series
or parallel connection.
Please observe the relevant safety requirements, e.g. IEC/EN 60079-11 and IEC/EN
60079-14, when installing and operating intrinsically-safe equipment.
Please refer to the chart below for the technical parameters and the approved limits (Ui, Ii, Ci, L
tion:
Level contact30V50mAnegligiblenegligible100 mW
U
i
I
i
C
i
Temperature contact30V50mAnegligiblenegligible100 mW
Pt100 Temperature Sensor30V50mAnegligiblenegligible100 mW
) for intrinsically-safe opera-
i, Pi
L
i
P
i
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