Bühler technologies Nivotemp NT-EL User manual

Fluidcontrol
Installation and Operation Instructions
Original instructions
Level switch
Nivotemp NT-EL
BE100025
08/2020
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.......................................................... BE100025
Version........................................................................ 08/2020

Nivotemp NT-EL
Contents
1 Introduction..................................................................................................................................................................................................................... 2
1.1 Intended Use.........................................................................................................................................................................................................2
1.2 Functionality......................................................................................................................................................................................................... 2
1.2.1 Liquid level monitoring ......................................................................................................................................................................2
1.2.2 Temperature monitor .........................................................................................................................................................................2
1.3 Ordering instructions NT-EL.............................................................................................................................................................................2
1.4 Scope of Delivery.................................................................................................................................................................................................. 3
2 Safety instructions.........................................................................................................................................................................................................4
2.1 Important advice.................................................................................................................................................................................................4
2.2 General hazard warnings ................................................................................................................................................................................. 5
3 Transport and storage ..................................................................................................................................................................................................6
4 Setup and connection................................................................................................................................................................................................... 7
4.1 Assembly................................................................................................................................................................................................................ 7
4.2 Electrical connections ........................................................................................................................................................................................ 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.......................................................................................................................................................................................10
7 Service and repair.......................................................................................................................................................................................................... 11
8 Disposal............................................................................................................................................................................................................................12
9 Appendices......................................................................................................................................................................................................................13
9.1 NT-EL Technical Data.........................................................................................................................................................................................13
9.2 NT-EL default pin assignment ....................................................................................................................................................................... 14
10 Attached documents....................................................................................................................................................................................................15
iBühler Technologies GmbHBE100025 ◦ 08/2020

Nivotemp NT-EL
1 Introduction
1.1 Intended Use
Level switches are used to monitor the liquid level and temperature in fluid systems.
Level switches must not be used 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. If necessary, filter the medium.
Please note the technical data in the appendix for the specific intended use, existing material combinations, as well as temper-
ature limits.
WARNING
All device models are solely intended for industrial applications. They are not safety com-
ponents. The devices must not be used if failure or malfunction thereof jeopardises the
safety and health of persons.
Use in explosive areas is prohibited.
1.2 Functionality
1.2.1 Liquid level monitoring
The measuring tube is located inside the tank. The level switches are located inside the measuring tube. These are activated by a
magnet inside the level switch float.
The contacts are soldered to the board, spaced as specified in the purchase order.
1.2.2 Temperature monitor
The temperature is monitored via thermal element soldered to the end of the contact board. Choose from temperature contacts
with fixed increments or a resistance thermometer (Pt100).
When equipped with resistance thermometer (model key “Pt100”) the temperature is output using the change in resistance
(0°C = 100Ω) of the Pt100.
Please note the technical data in the appendix.
1.3 Ordering instructions NT-EL
Model key
NT-EL
G1/2
M20
UNF
Brass
MS
Version
Model designation
Connection
Plug
XX
Temperature signal
Pt100
Temperature contact NC contact
TE50NC
TE60NC
TE70NC
TE80NC
= temperature sensor
= 50 °C
= 60 °C
= 70 °C
= 80 °C
M12
Length
280
370
500
variable (please specify)
XX XX XX XX
= G1/2
= M20x1.5
= 7/8-14 UNF
XX
Number of level contacts
1K or 2K (NC / NO)
*
*max. 1 level contact
2 Bühler Technologies GmbH BE100025 ◦ 08/2020

Nivotemp NT-EL
Ordering example
You require: Level switch with connector M20x1.5, length L= 370 mm,
2 level contacts, L1 = 280 mm NC / L2 = 320 mm NO
Order NT-EL-MS-M20-M12/370-2K-280NC/320NO
1.4 Scope of Delivery
– Level switch
– Product documentation
– Connection/mounting accessories (optional)
3Bühler Technologies GmbHBE100025 ◦ 08/2020

Nivotemp NT-EL
2 Safety instructions
2.1 Important advice
Operation of the device is only valid if:
– the product is used under the conditions described in the installation- and operation instruction, the intended application
according to the type plate and the intended use. In case of unauthorized modifications done by the user Bühler Technolo-
gies GmbH can not be held responsible for any damage,
– when complying with the specifications and markings on the nameplates.
– the performance limits given in the datasheets and in the installation- and operation instruction are obeyed,
– monitoring devices and safety devices are installed properly,
– service and repair is carried out by Bühler Technologies GmbH,
– only original spare parts are used.
This manual is part of the equipment. The manufacturer keeps the right to modify specifications without advanced notice. Keep
this manual for later use.
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 not to inhale toxic gasses Wear respiratory equipment
Warns of corrosive liquids Wear a safety mask
Warns of explosive areas Wear gloves
4 Bühler Technologies GmbH BE100025 ◦ 08/2020

Nivotemp NT-EL
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.
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.
5Bühler Technologies GmbHBE100025 ◦ 08/2020

Nivotemp NT-EL
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.
6 Bühler Technologies GmbH BE100025 ◦ 08/2020

Nivotemp NT-EL
4 Setup and connection
DANGER Toxic, acidic gases/liquids
Protect yourself from toxic, corrosive gasses/liquids when performing any type of work.
Wear appropriate protective equipment.
4.1 Assembly
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 comes fully assembled and can be mounted to the tank with 30 Nm of torque. 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.
The level contacts are mounted (with the tank empty) as NO contact (NO) or NC contact (NC).
The contact logic assumes the level switch is installed in an empty tank, i.e. it is only in the operating position once filled.
4.2 Electrical connections
The level switch is powered by 24V (max. 30V). The switch connects with a cable and standard M12 plug-in connectors. Please
refer to the appendix for installation dimensions and plug configuration.
7Bühler Technologies GmbHBE100025 ◦ 08/2020

Nivotemp NT-EL
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. This is reduces by high stress and / or incorrect or the absence of protective cir-
cuits when switching inductive, capacitive or lamp loads.
It’s therefore important to ensure NEVER to exceed one or several of the maximum approved limits, even temporarily, and to
install a contact protective circuit for loads which are not purely ohmic. Using test lamps when installing the devices is also pro-
hibited, 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.
Contact protective circuits for reed switches
For direct current voltage a recovery diode per figure A must be connected parallel to the contact.
For alternating current voltage an RC circuit per Figure B and Table 1 must be connected parallel to the contact.
A B
Load
Contact
Recovery diode
Load
Contact
RC circuit
Load in VA 10 25 50
Voltage at contact V R/Ohm C/µF R/Ohm C/µF R/Ohm C/µF
24 22 0.022 1 0.1 1 0.47
60 120 0.0047 22 0.022 1 0.1
110 470 0.001 120 0.0047 22 0.022
230 470 0.001 470 0.001 120 0.0047
Please note the max. voltage/load ratings of the respective level contacts!
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.
The maximum values specified for the respective contact types apply.
Level contact with reed switches can therefore be used for SPS applications as well as for high loads (within the maximum lim-
its) without hesitation.
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.
8 Bühler Technologies GmbH BE100025 ◦ 08/2020