Page 1
Operating Instructions
for
Conductive Level Switches
Model: NEK-...
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NEK
1. Contents
1. Contents ........................................................................................................ 2
2. Note .............................................................................................................. 3
3. Instrument Inspection .................................................................................... 3
4. Regulation Use .............................................................................................. 3
5. Operating Principle ........................................................................................ 4
6. Mechanical Connection ................................................................................. 4
6.1. Check service conditions: .................................................................... 4
6.2. Installation ............................................................................................ 4
7. Electrical Connection .................................................................................... 4
7.1. General ................................................................................................ 4
7.2. NPN switching output (NEK-1) ............................................................. 5
7.3. PNP switching output (NEK-2) ............................................................. 5
7.4. Relay switching output (NEK-3) ........................................................... 5
8. Commissioning .............................................................................................. 5
9. Maintenance ................................................................................................. 6
10.Technical Information .................................................................................... 6
11.Order Codes ................................................................................................. 7
12.Dimensions ................................................................................................... 7
13.EU Declaration of Conformance .................................................................... 8
Manufactured and sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: +49(0)6192-2990
Fax: +49(0)6192-23398
E-Mail: info.de@kobold.com
Internet: www.kobold.com
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2. Note
Please read these operating instructions before unpacking and putting the unit
into operation. Follow the instructions precisely as described herein.
The devices are only to be used, maintained and serviced by persons familiar
with these operating instructions and in accordance with local regulations
applying to Health & Safety and prevention of accidents.
When used in machines, the measuring unit should be used only when the
machines fulfil the EC-machine guidelines.
3. Instrument Inspection
Instruments are inspected before shipping and sent out in perfect condition.
Should damage to a device be visible, we recommend a thorough inspection of
the delivery packaging. In case of damage, please inform your parcel service /
forwarding agent immediately, since they are responsible for damages during
transit.
Scope of delivery:
The standard delivery includes:
Conductive Level Switch Model: NEK-...
Operating Instructions
4. Regulation Use
Any use of the Conductive Level Switch, model: NEK, which exceeds the
manufacturer’s specification, may invalidate its warranty. Therefore any resulting
damage is not the responsibility of the manufacturer. The user assumes all risk
for such usage.
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5. Operating Principle
The Kobold Level Switch of model NEK is a complete functional unit which is
specially designed for monitoring conductive liquids under extreme conditions.
Due to the design without any moving or protruding parts, the switches are very
suitable for monitoring critical media with, for example, solid content, negligible
density or high viscosity. The double-thread allows a variety of installations. The
length of the shaft can be extended by attaching an additional protective tube.
The instruments operate on the conductive principle of measurement. The
conductive medium touches both electrodes causing a negligible alternating
current to flow; the output state changes.
6. Mechanical Connection
6.1. Check service conditions:
Chemical resistance of materials
Maximum operating pressures
Maximum service temperature
6.2. Installation
Tank installation may be the side or from the top (universal)
Avoid pressure and tensile/torsional stress
Check connections for leakage
7. Electrical Connection
7.1. General
Important! Make sure that the voltages in your plant correspond
with the Level Switch voltages
Make sure that the supply wires are de-energized.
Wire the connection cable to your supply according to the terminal connection
diagrams below.
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/
C
Attention! Incorrect wiring will lead to damage of the unit’s
electronics.
If the unit is installed in a metallic, conductive container, this container must be
connected with the NEK supply potential GND, otherwise it may cause functional
problems by potential differences.
7.2. NPN switching output (NEK-1)
braun
brown : 18-29 V D
schwarz/black : NPN O.C. max.300 mA
NPN
blau/blue :GND
7.3. PNP switching output (NEK-2)
PNP
7.4. Relay switching output (NEK-3)
NO
Relay
NC
8. Commissioning
braun/brown : 18-29 V DC
schwarz/black : PNP O.C. max.300 mA
blau/blue : GND
braun/brown : 18-29 V DC
grau/grey : Relay out n.o.
weiß/white : Relay out n.c.
schwarz/black : Relay out common
blau/blue :GND
The measuring instruments are pre-set and are ready for operation after electrical
connection.
The LED signals the switch state of the level switch.
LED off: no power supply
LED off with short "ON pulses":
Power supply on / switch state de-activated (dry)
LED on: Power supply on / switch state activated (wet)
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9. Maintenance
The Conductive Level Switch is maintenance-free.
Should the electrodes be contaminated with a non-conductive coating (oil,
grease, etc.), they can be cleaned with a suitable tool (e.g. cloth). Do not use a
cleaner that would damage the plastic housing.
10. T echnical Information
Case: PPS (Rhyton) or polypropylene
Electrodes: stainless steel 1.4571
Connections: R 3/4 or 3/4 NPT male thread
Operating temperature: -25 to +85 °C (PPS)
-25 to +60 °C (polypropylene)
Max. pressure: 20 bar (PPS)
6 bar (polypropylene)
Installation position: horizontal or vertical
Contact components: open collector (NPN or PNP)
wet signal
Option:
relay (floating changeover contact)
Electrical connection: 2 m encapsulated cable
3-core screened (open collector)
5-core unshielded (relay)
Supply: 18-29 VDC < 20 mA
Switch-in delay: dry/wet: 0.5 sec.
wet/dry: 0.5 sec.
Sensitivity: approximately 50 k
Min. Conductance: approximately 100 µS/cm
Switch capacity: open collector:
max. 32 V / max. 100 mA / short-circuit-proof
Relay:
max. 1 A / 30 V / short-circuit-proof
Protection type: IP 68
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11. Order Codes
Example: NBK-1136 R20 C
12. Dimensions
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13. EU Declaration of Conformance
We, KOBOLD-Messring GmbH, Hofheim-Ts, Germany, declare under our sole
responsibility that the product:
Conductive level switch model: NEK -...
to which this declaration relates is in conformity with the standards noted below:
EN 61000-6-4:2011-09
Electromagnetic compatibility (EMC) - Part 6-4: Generic standards - Emission
standard for industrial environments
EN 61000-6-2:2006-03
Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity for
industrial environments
EN 61010-1:2011-07
Safety requirements for electrical equipment for measurement, control and
laboratory use - Part 1: General requirements
EN 60529:2014-09
Degrees of protection provided by enclosures (IP Code)
Also the following EC guidelines are fulfilled:
2014/35/EU Low Voltage Directive
2011/65/EU RoHS (category 9)
Hofheim, 12. May 2016
H. Peters M. Wenzel
General Manager Proxy Holder
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