Kobold LNK User manual

Operating Instruction
for
Conductive Level Switch
Model: LNK

LNK
Page 2 LNK K06/0422
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 3
5.Operating Principle ........................................................................................ 4
5.1.Head transmitter LNR (Option LNK-...NPK, LNK-...NPS) .................... 4
5.2.External electrode relay (e.g. NE-104, 304) ......................................... 4
6.Mechanical Connection ................................................................................. 5
6.1.Welding details for sleeves LZE ........................................................... 6
7.Electrical Connection .................................................................................... 7
7.1.Connection without evaluating electronic (head transmitter) Model
LNK-...00K, LNK-...00S ........................................................................ 7
7.2.Connection with evaluating electronic (head transmitter) Model LNK-
...NPK, LNK-...NPS .............................................................................. 8
7.3.Plug assignment of M12-plug without evaluating electronics (head
transmitter) Model LNK-...00S ............................................................ 9
7.4.Plug assignment of M12-plug with evaluating electronics (head
transmitter) Model LNK-...NPS .......................................................... 10
8.Technical Information .................................................................................. 11
9.Order Codes ............................................................................................... 12
10.Maintenance ............................................................................................... 13
11.Dimensions ................................................................................................. 14
12.EU Declaration of Conformance ................................................................. 15
Manufactured and sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: [phone]
Fax: [phone]
E-Mail: [email protected]
Internet: www.kobold.com

LNK
LNK K06/0422 Page 3
2. Note
Please read these operating instructions before unpacking and putting the unit
into operation. Follow the instructions precisely as described herein.
The instruction manuals on our website www.kobold.com are always for currently
manufactured version of our products. Due to technical changes, the instruction
manuals available online may not always correspond to the product version you
have purchased. If you need an instruction manual that corresponds to the
purchased product version, you can request it from us free of charge by email
([email protected]) in PDF format, specifying the relevant invoice number and
serial number. If you wish, the operating instructions can also be sent to you by
post in paper form against an applicable postage fee.
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: LNK
4. Regulation Use
Any use of the Conductive Level Switch, model: LNK, 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.

LNK
Page 4 LNK K06/0422
5. Operating Principle
The conductive KOBOLD level probes LNK together with the transducer for head
mounting or the external evaluating electronic are used for level detecting. This
method is based on the evaluation of the electrical conductivity of the medium. In
combination with the KOBOLD LZE or LZE-R weld-in sleeves, the probe provides
a measuring point that has no dead space and meets hygiene standards
(EHEDG approval certificate). This level switch is therefore ideally suited for
CIP/SIP cleaning.
The level switch is available with 1 or 2 - 4 electrodes. As an option, they can be
delivered with an E-CTFE coating. This allows foaming media to be detected
reliably.
The output signal from the probes with head mounted transmitter can be
connected directly to a PLC for evaluation. This means lower installation costs,
minimum wiring requirements and a high degree of noise immunity.
The device is available with an optional M12x1 plug connector.
5.1. Head transmitter LNR (Option LNK-...NPK, LNK-...NPS)
A usage of the head transmitter LNR is only possible, when the LNK as a 2-
stem probe, contains an earth stem and a monitoring stem.
The transmitter integrated in the electrode head provides a control voltage
between the detecting electrode and the earth electrode. When the electrodes dip
into a conductive liquid, a small alternating current starts flowing. An integrated
switching amplifier detects this alternating current and switches the
24 VDC active output accurately, as soon as an adjusted trigger threshold is
crossed. When the liquid drops below the limit value electrodes, the output
becomes inactive again.
5.2. External electrode relay (e.g. NE-104, 304)
When the LNK is used as a 3-stem or 4-stem probe (2 or 3 switching points), the
evaluation takes place with an external electrode relay (see instruction manual
and technical details of the external electrode relay).
In order to get an additional switching point, the electrically conductive and
grounded vessel wall can be used as ground terminal. Therefore the ground
electrode can be used as an additional switching electrode.

LNK
LNK K06/0422 Page 5
6. Mechanical Connection
 Please note the maximum torque while mounting the instrument: 10 – 20 Nm
(measuring instrument connection G ½) and 25 – 30 Nm (measuring
instrument connection G 1).
 The electrodes must be mounted in a vertical position in the lid or the ground
of the vessel which must be detected.
 The mounting must be done in a way that there is no short circuit of the
electrodes neither to the walls of the vessel nor to itself.
 Note during mounting that the electrodes do not bend and the medium can
drain off easily when they are not longer touched by the fluid.
 The ground electrode must be at least as long as the longest switching
electrode.
 If not using the weld-in sleeves type LZE one must note there is a conducting
connection to the wall of the vessel. An additional grounding to the pipework or
the wall of the vessel is necessary when using an isolating sealing.
Shortening the electrodes:
 The tip of the electrodes is equal to the switching point and can be shortened if
necessary.
 Note, that the bracing of the electrode in the thread-piece is not too heavily
loaded during shortening.
 Do not harm the isolation of the electrode.
 After shortening, make sure that the E-CTFE isolation is removed of about a
length of 5 mm from the tip of the electrode.

LNK
Page 6 LNK K06/0422
6.1. Welding details for sleeves LZE
Welding in tanks and pipes:
1. Drill a hole with a diameter equivalent to outer diameter of the sleeve; max.
tolerance +0,2 mm
2. Weld the sleeve at 4 points
3. Screw in the blind socket
4. Weld the sleeve segments crosswise between already welded 4 points.
4 sleeve segments for M12 and G 1/2”; 8 sleeve parts for G1”
Attention! In order to avoid deforming or red-hot turning of the
sleeve, pauses between individual sleeve segments should be
sufficient enough to allow cooling down of the sleeve.

LNK
LNK K06/0422 Page 7
7. Electrical Connection
Attention! Make sure that the voltage values of your system accord
to the voltage values of the monitoring unit.
 Make sure that the supply wires are de-energised.
 Connect the supply wires and the output signal to the shown pins.
 We recommend the use of wires with cross sectional area of min. 0,25 mm²
Attention! A wrong connection of the plug pins can damage the
unit’s electronic!
7.1. Connection without evaluating electronic (head transmitter)
Model LNK-...00K, LNK-...00S
Reference: wall of vessel
(only possible with an electrical
conductive connection to the metal tank)
1 Electrode 1
2 Electrode 2
3 Electrode 3
4 Electrode 4
5 earthing of housing (Reference)
Reference: longest electrode
1 Reference electrode
2 Electrode 2
3 Electrode 3
4 Electrode 4
5 earthing of housing
E1 M
12345
E2 E3 E4

LNK
Page 8 LNK K06/0422
7.2. Connection with evaluating electronic (head transmitter)
Model LNK-...NPK, LNK-...NPS
1. Electrode unit: Switching point equal to the electrode length, earthing through
vessel wall
2. Electrode unit: 1 electrode as switching point
1 Power supply: +Vs / GND*
2 Power supply: GND / +Vs*
3 Output: Transistor PNP
(Uoff = +Vs - 1 V)
4 Sensitivity: +Vs / GND / open
5 Electrode 1: Ground electrode or
wall of vessel
6 Electrode 2: Detecting sensor
electrode
* see chapter 7.2.1
7.2.1. Setting the full /empty signal function:
The output function (full / empty signal) is switchable by changing the polarity of
the supply voltage.
Power suppl
y
Probe Output
Terminal 3
LED
Terminal 1 Terminal 2
GND + Vs immersed Uout on
dr
y
0 V off
+ Vs GND immersed 0 V on
dr
y
Uout off
external
link

LNK
LNK K06/0422 Page 9
7.2.2. Setting the sensitivity:
1. Configurate the instrument according to sensitivity step 1
2. Cover probe with the medium to be measured
3. If the Probe LED does not light up, try steps 2, 3 and 4 in succession, until the
probe LED is illuminated.
Step Sensitivity Connection 4 Jumper
position
1 0.1 k + Vs inside
2 1 k + Vs outside
3 10 k open outside
4 100 k GND outside
7.3. Plug assignment of M12-plug without evaluating
electronics (head transmitter)
Model LNK-...00S
Reference: wall of vessel
(only possible with an electrical conductive
connection to the metal tank)
1 Electrode 1
2 Electrode 2
3 Earthing of housing (Reference)
4 Electrode 3
5 Electrode 4
Reference: longest electrode
1 Reference electrode
2 Electrode 2
3 Earthing of housing
4 Electrode 3
5 Electrode 4
21
34
5

LNK
Page 10 LNK K06/0422
7.4. Plug assignment of M12-plug with
evaluating electronics (head transmitter)
Model LNK-...NPS
1 Power Supply + Vs / GND
2 Sensitivity + Vs / GND / open
3 Power Supply GND / +Vs
4 Output: Transistor PNP
7.4.1. Setting the output function at option M12-plug
The output function (full/empty signal) is switchable by changing the polaritiy of
the supply voltage.
Power Suppl
y
Sensor Output
Plug-PIN 4
LED
Plu
g
-PIN 1 Plu
g
-PIN 3
GND + Vs immersed Uout on
dr
y
0 V off
+ Vs GND immersed 0 V on
dr
y
Uout off
7.4.2. Setting the sensitivity at option M12-plug
1. Configurate the instrument according to sensitivity step 1
2. Cover probe with the medium to be measured
3. If the Probe LED does not light up, try positions 2, 3 and 4, until the probe LED
is illuminated.
Step Sensitivity Plug-Pin 2 Jumper
position
1 0.1 k + Vs inside
2 1 k + Vs outside
3 10 k open outside
4 100 k GND outside
21
34

LNK
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8. Technical Information
Measuring principle: conductive
Process temperature: 0...100 °C,
150 °C for CIP process
Ambient temperature: 0...70 °C
Operating pressure: max. 10 bar
Material
• Head, thread supports: stainless steel 1.4404
• Insulating section: PEEK
• Electrode stem: stainless steel 1.4404
• Stem coating: E-CTFE, coating 0.3 mm
Electrode length: 4 - 1500 mm
Process connection: G ½ with 1 electrode stem
G 1 with 2 - 4 electrode stems
Connection: Threaded cable gland connection
M16x1.5
optional M12x1 plug
Protection: IP 67
Min. conductivity: 10 µS/cm
Weight: approx. 0.6 kg
Switch- electronic
For 1-or 2-stem probe:
Internal Module for one switching point
Option NPK/NPS
Power supply: 15...36 VDC / 15 mA
Electrode voltage: approx. 2 VAC / 600 Hz
Sensitivity (adjustable): 4 steps 0.1 / 1 / 10 / 100 kΩ
Function: full / empty report (determined via the polarity of
the supply voltage)
Output: PNP Transistor output (open coll.),
U
out = +Vs – 1 V
max. 50 mA, short-circuit-proof
Switch delay (fixed): 1 s
Weight: approx. 40 g
LED-Indication: Illuminated when medium contacts the
electrodes
additional technical details see separate data sheet
For 1- up to 4-stem probe:
External electrode relay NE104 and NE304
(see separate data sheet)

LNK
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9. Order Codes
Example order: LNK-1 2 0 A AAA 00K
Model Design
(Process
connection)
Electrode
material
Electrode
coating
Length
of 1. stem
Length
of 2. stem
Length
of 3. stem
Length
of 4. stem
Evaluation/
electronic connection
LNK-
1 = electrode
(G 1/2)
2 = 2 electrodes
(G 1)2
3 = 3 electrodes
(G 1)
4 = 4 electrodes
(G 1)
2 = stainless
steel
0 = without
coating
E = E-CTFE-
coating
A = 4 mm stump
B = 100 mm
C = 250 mm
D = 500 mm
E = 750 mm
F = 1000 mm
G = 1500 mm
A = 4 mm stump
B = 100 mm
C = 250 mm
D = 500 mm
E = 750 mm
F = 1000 mm
G = 1500 mm
0 = no other
stem
A = 4 mm stump
B = 100 mm
C = 250 mm
D = 500 mm
E = 750 mm
F = 1000 mm
G = 1500 mm
0 = no other
stem
A = 4 mm stump
B = 100 mm
C = 250 mm
D = 500 mm
E = 750 mm
F = 1000 mm
G = 1500 mm
0 = no other
stem
00K = without electronic,
cable con. M16x1.5
00S = without electronic,
M12x1 plug
Only for 1- or 2-stem
probe:
NPK = switching electronic;
PNP switch output,
thread. cable con.
NPS = switching electronic;
PNP switch output,
M12x1 plug
Note:
 EHEDG certification of the connection system in combination with weld-in
sleeve LZE
 External switch electronic: Electrode relay NE 104 and NE 304

LNK
LNK K06/0422 Page 13
10. Maintenance
The conductive level electrodes work completely maintenance free. Occasionally,
the electrode tips should be checked for deposits or corrosion and cleaned
accordingly. Insulated layers can result in false alarms.

LNK
Page 14 LNK K06/0422
11. Dimensions

LNK
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12. EU Declaration of Conformance
We, KOBOLD Messring GmbH, Hofheim-Ts, Germany, declare under our sole
responsibility that the product:
Conductive Level Switch Model: LNK-…
to which this declaration relates is in conformity with the standards noted below:
EN 61000-6-4:2011
Electromagnetic compatibility (EMC) - Part 6-4: Generic standards - Emission
standard for industrial environments
EN 61000-6-2:2006
Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity for
industrial environments
EN IEC 63000:2018 Technical documentation for the assessment of electrical
and electronic products with respect to the restriction of hazardous substances
Also, the following EEC guidelines are fulfilled:
2014/30/EU EMC Directive
2011/65/EU RoHS (category 9)
2015/863/EU Delegated Directive (RoHS III)
We confirm that the materials used are fully suitable for direct contact with food
and comply with EC Regulation
1935/2004
10/2011,
and (FDA) CFR21.
Hofheim, 13 April 2022
H. Volz M. Wenzel
General Manager Proxy Holder