Buhler NS 25 AM-Atex Owner's manual

Fluidcontrol
Installation and Operation Instructions
Original instructions
Level switch for external mounting
NS 25 AM-Atex
BE200005
10/2020
Bühler Technologies GmbH, Harkortstr. 29, D-40880 Ratingen
Tel. [phone] / 49 89-0, Fax: [phone] / 49 89-20
E-Mail: [email protected]
Internet: www.buehler-technologies.com

Bühler Technologies GmbH, Harkortstr. 29, D-40880 Ratingen
Tel. [phone] / 49 89-0, Fax: [phone] / 49 89-20
Internet: www.buehler-technologies.com
E-Mail: [email protected]
Read this instruction carefully prior to installation and/or use. Pay at-
tention particularly to all advises and safety instructions to prevent in-
juries. Bühler Technologies can not be held responsible for misusing
the product or unreliable function due to unauthorised modifications.
All rights reserved. Bühler Technologies GmbH 2020
Document information
Document No......................................................... BE200005
Version.........................................................................10/2020
Part No........................................................................9032068

NS 25 AM-Atex
Contents
1 Introduction..................................................................................................................................................................................................................... 2
1.1 Intended Use.........................................................................................................................................................................................................2
1.2 Product Description............................................................................................................................................................................................2
1.3 Scope of Delivery..................................................................................................................................................................................................2
1.4 Ordering Instructions......................................................................................................................................................................................... 2
1.5 Type plate ..............................................................................................................................................................................................................2
2 Safety instructions......................................................................................................................................................................................................... 3
2.1 Important advice................................................................................................................................................................................................. 3
2.2 General hazard warnings .................................................................................................................................................................................4
3 Transport and storage .................................................................................................................................................................................................. 5
4 Installation and connection........................................................................................................................................................................................6
4.1 Installation ............................................................................................................................................................................................................6
4.2 Electrical connections (intrinsically safe).....................................................................................................................................................6
4.2.1 Intrinsically-safe connection............................................................................................................................................................ 6
4.2.2 PA connection (potential equalisation) .........................................................................................................................................7
4.3 Information on the correct operation of reed contacts in Bühler level switches.............................................................................8
5 Operation and control ..................................................................................................................................................................................................9
6 Cleaning and Maintenance........................................................................................................................................................................................11
7 Service and repair..........................................................................................................................................................................................................12
7.1 Accessories........................................................................................................................................................................................................... 12
8 Disposal............................................................................................................................................................................................................................13
9 Appendices..................................................................................................................................................................................................................... 14
9.1 Technical Data.................................................................................................................................................................................................... 14
9.2 Contacts ................................................................................................................................................................................................................15
10 Attached documents................................................................................................................................................................................................... 16
iBühler Technologies GmbHBE200005 ◦ 10/2020

NS 25 AM-Atex
1 Introduction
1.1 Intended Use
According to EN 60079-11, the NS25AM-Atex series level switch is a simple electrical apparatus without separate voltage source
intended for tank-top installation.
With intrinsically safe connection, the level switch may be installed in explosive areas zone 1 and zone 2 (group IIB). It is used to
monitor the level inside a tank.
Before installing the level switch, verify the listed technical data meet the application parameters. Also observe the applicable
requirements of EN60079-14.
Further verify all contents are complete.
Please note the specific values of the level switch when connecting and the correct version when ordering spare parts.
1.2 Product Description
According to EN 60079-11, NS25AM-Atex level switches are simple electrical apparatuses without separate voltage source. When
used in explosive areas, they may only be operated on an intrinsically safe electric circuit (observe requirements of these instruc-
tions and EN 60079-14, as well as technical specifications). The level switches can be used to monitor the level inside a tank. In
this case, the measuring tube is located outside the tank. Adjustable height level contacts (bistable reed switches) are mounted
on the scale plate.
The level contacts are activated by a magnet inside the level switch float. Every level switch also has a display. The display has a
scale and, like the unit, is made from stainless steel.
The level switches are mounted to the tank with screws and level switch flange.
1.3 Scope of Delivery
– Level switch
– Product documentation
– Connection/mounting accessories (optional)
1.4 Ordering Instructions
When ordering, always specify the measurement L1 and the number and type of contacts!
Model NS 25/15 AM-Atex NS 25/25 AM-Atex
Item no.: 2001999A 2003999A
1.5 Type plate
Example:
TÖA-80-Atex-M3
1140899A KW: 37-2017 001
Manufacturer and address
Model designation
Order no.+Item no.+Metre
Controller values
Temperature specifications
Pressure specifications
Year of manufacture
Ui=30V, li= 50mA simple apparatus
T Medium < 80°C, -20°C < Ta < 100°C
p max. = 15 bar
Read manual! Year: 2017
Bühler Technologies GmbH
Harkortstr. 29 D-40880 Ratingen
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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 EN60079-14 and EN60079-17 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-, specific-
ation- or technical data without prior notice. Please keep these instructions for future reference.
Signal words for warnings
DANGER
Signal word for an imminent danger with high risk, resulting in severe injuries or death if not avoided.
WARNING
Signal word for a hazardous situation with medium risk, possibly resulting in severe injuries or death if not
avoided.
CAUTION
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.
NOTICE
Signal word for important information to the product.
Warning signs
These instructions use the following warning signs:
Warns of a general hazard General information
Warns of voltage Unplug from mains
Warns not to inhale toxic gasses Wear respiratory equipment
Warns of corrosive liquids Wear a safety mask
Warns of explosive areas Wear 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,
– compliance with national installation regulations.
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.
– Do not install damaged or defective spare part. If necessary, visually inspect prior to installation to determine any obvious
damage to the spare parts.
– Operation in Ex atmosphere prohibited.
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.
DANGER Toxic, 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. They must be stored in a covered, dry, vibration-
and dust-free location at a temperature between -20°C to +60°C.
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4 Installation and connection
4.1 Installation
The level switch mounts to the outside of the tank with the flanges. Ensure all seals are large enough to prevent cross-section
constriction in the connection fitting. All screws must be tightened to the same torque. The float is preinstalled in the level
switch.
4.2 Electrical connections (intrinsically safe)
DANGER Electrical voltage
Electrocution hazard.
a) Disconnect the device from power supply.
b) Make sure that the equipment cannot be reconnected to mains unintentionally.
c) The device must be opened by trained staff only.
d) Regard correct mains voltage.
Please refer to the compatibility charts in the appendix or the data sheet of your level switch for the pin assignment and elec-
trical data of your level switch. It connects with plugs.
Please note, the level switch must be connected to the earthed tank via the existing external PA connection.
4.2.1 Intrinsically-safe connection
CAUTION Explosion 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. EN60079-11 and EN60079-14, when
installing and operating intrinsically-safe equipment.
According to EN60079-14, the level contacts must be operated on an intrinsically safe electric circuit. On a separate intrinsically
safe electric circuit, the switching parameters of the level contact are Ui ≤ 30 V, Ii ≤ 50 mA.
When operating several level contacts on the same electric circuit, the switching values apply to the entire electric circuit.
Adding the switching values based on the number of level contacts on an electric circuit is not permitted and presents an explo-
sion hazard.
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4.2.2 PA connection (potential equalisation)
CAUTION Electrostatic charge
Level switch housings must be connected to the tank via external PA connection!
Ensure the level switch is adequately earthed (minimum conductor cross-section 4mm2).
Please also particularly observe the requirements of EN 60079-14.
The level switch has a separate PA connection. This is identified by the decal shown on the right. A PA cable is connected
with an M5 thread. The PA cable for potential equalisation between the level switch and the tank is not included and
must be supplied and installed by the customer.
Layout of the PA connection:
1 Nut 4 PA cable (to be installed by the customer)
2 Serrated or tooth washer 5 Washer
3 Washer
PA connection example:
Drawing A
1 PA decal 4 Tank
2 Level Switch 5 PA connection on the tank
3 PA connection on the level switch 6 PA cable
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4.3 Information on the correct operation of reed contacts in Bühler level switches
Based on their construction, reed contacts are very long lasting and reliable components. Yet the following should be considered
when using them:
Life of reed switches
The life of reed switches can be up to 109 cycles. It is reduced by excess loads.
It’s therefore important to ensure NEVER to exceed one or several of the maximum approved limits, even temporarily. Since it
is a component on an intrinsically safe electric circuit, this is not permissible for explosion protection reasons and more. Using
test lamps when installing the devices is also prohibited, as these can temporarily allow too much current to flow, which can
damage the reed contacts. In this case non-volatile testing equipment should always be used.
Voltages and currents
All Bühler level contacts with reed switch can switch minimal Switching voltages of 10 µV and minimal switching currents of 1
µA.
On a separate intrinsically safe electric circuit, the switching parameters of the level contact are Ui ≤ 30 V, Ii ≤ 50 mA.
Contact material
All reed switches in Bühler level contacts use rhodium as the contact material for the actual contact areas.
Magnetic fields
Avoid external magnetic fields, including from electric motors. These can interfere with the function of the reed switches.
Mechanical loads
Do not expose the level switch to strong blows or bending.
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