Kobold NE-104 User manual

Operating Instructions
for
Conductive Level
Limit Switch
Model: NES, NE-104/-304

NES
page 2 NES K05/0922
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 4
5.Operating Principle ........................................................................................ 4
6.Mechanical Connection ................................................................................. 5
7.Electrical Connection .................................................................................... 6
7.1Conductive Level Switch (Electrodes with screw in thread and
housing) ............................................................................................... 6
7.2NE-104 Electrode Relay ...................................................................... 7
7.3NE-304 Electrode Relay ...................................................................... 8
7.4Application examples with Electrode Relay NE-104 .......................... 10
8.Commissioning............................................................................................ 12
9.Locating and Remedying Faults .................................................................. 12
10.Maintenance ............................................................................................... 13
11.Technical Data ............................................................................................ 14
12.Order Codes ............................................................................................... 15
13.Dimensions ................................................................................................. 16
13.1Electrodes with Housing .................................................................... 16
13.2Electrode Relay ................................................................................. 17
14.Disposal ...................................................................................................... 18
15.EU Declaration of Conformance ................................................................. 19
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

NES
NES K05/0922 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 Limit Switch model: NES
 respectively conductive electrode relay model: NE

NES
page 4 NES K05/0922
4. Regulation Use
The KOBOLD limit switches of model NES are used in connection with the
electrode relay, model: NE, for level monitoring and pump control of conductive
liquids. The design without any moving parts allows service with critical media
with, for example, solid content, negligible density or high viscosity.
The minimum medium conductivity should be 20 µS/cm.
Any use of the device which exceeds the manufacturer’s specifications, may
invalidate its warranty. Therefore, any resulting damage is not the responsibility of
the manufacturer. The user assumes all risk for such usage.
5. Operating Principle
The instruments operate on the conductive principle. A low a.c. voltage is applied
between the conductive wall of the tank or the ground electrode (longest
electrode) and one respectively several switching point electrode. If the
conductive medium touches the electrodes, a negligible alternating current flows
across the electrodes and the conductive medium to the electrode relay. The
relay amplifies the alternating current and operates one bi-stable interval relay
with lock which is therefore suitable for an interval switching e.g. of a pump
control (min./max. control).
Unlike to the NE-104 with only one limit value indication, one connection for a
ground electrode and one min. and max. electrode, the relay NE-304 can observe
two signals. The NE-304 offers connections for one ground electrode and two
level limits at a time.
The outputs of NE-304 can both be operated as a min./max. control or separately
as a limit switch (alarm) and a min./max. control.

NES
NES K05/0922 page 5
6. Mechanical Connection
The electrodes can for example be screwed into the tank cover and sealed via a
pipe thread. The electrode length corresponds to the desired switching points and
may be shortened as necessary. The electrode tip must be free of insulating
materials. The electrodes must be installed so that the electrode rods or the
pendant electrodes are not short-circuited neither by the side of the tank, nor by
each other. Please ensure that the rods do not bend. The reference or ground
electrode must be at least as long as the longest switching electrode. If the side
of the tank is adequately conductive and is not coated with insulating material, it
can be used as a ground electrode. The clearance between the switching
electrode and the side of the tank should be as small as possible, so that the
conductivity of the measuring distance does not drop below 20S/cm.
Generally, please note:
 The level probes are generally intended for vertical installation.
 Short level electrodes, up to approx. 300 mm in length, can be installed in
other positions.
 Long level electrodes must be supported if subjected to high lateral loads.
 If used in liquids which form a conductive coating on the electrode insulation,
push the spacer away from the end of the electrode insulation by at least
 150 mm. This means that you will obtain a high transition resistance with an
uncovered electrode.
 When shortening an electrode, please ensure that electrode cladding is not
damaged at other places during the trimming operation. Remove the rod
cladding at the tip of the probe over a length of 3 - 5 mm.
 The screw in thread should be sealed with appropriate sealant.
Ensure that the insulation of the rods is not damaged during
insertion of the rods into the flange or the screw-fitting.

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page 6 NES K05/0922
7. Electrical Connection
7.1 Conductive Level Switch (Electrodes with screw in thread
and housing)
 The Conductive Level Switch is supplied with built-in terminal block for
electrical connection.
 Numbering: shortest electrode 1; second-shortest electrode 2, etc.
 The Conductive Level Switch can only be used in conjunction with a suitable
electrode relay (e.g. NE-104 or NE-304).
Ensure that the cable gland and the housing cover of the limit switch
are strongly tightened after connection.
Maximum cable length: 300 m, minimum cross-section 0,5 mm².
Starting at a cable length of approx. 15 m and for EMC critical
installation environment, a screened and low capacity cable must be
used which is connected to an adequate shiled ground

NES
NES K05/0922 page 7
7.2 NE-104 Electrode Relay
The NE-104 electrode relay is the standard relay for all
conductive limit electrodes. It is supplied with a
quiescent current relay, i.e., the relay picks up (contact
6-7 closes) when auxiliary power is applied. If the
electrodes are wetted or the power fails, the relay
disengages (contact 7-8 closes). The signal lamp (red
LED) is energised when the relay picks up.
Electrode connection
Usage as Min./Max. switch (2 electrodes)
 Connect the ground or reference electrode to terminal 14.
 Connect the switching electrode to terminal 15.
Level Relay LED
Below the switching electrode relay picks up, contact 6-7 closed on
Reaches or above the switching electrode relay drops out, contact 7-8 closed out
Usage as interval control (3 electrodes)
 Connect the ground or reference electrode to terminal 14.
 Connect the Max-switching electrode to terminal 15 and the Min-switching
electrode to terminal 16.
 Contact 6-7 is closed when the tank is empty. When the liquid reaches the
Max. electrode, the relay changes over and contact 7-8 closes. The relay
remains changed over until the level falls below the Min. electrode. The
interval then repeats itself.
 The changeover contact may be used for evacuating or filling - as shown in the
circuit examples.
Terminating the mains voltage
 The mains voltage is terminated at terminals 1 and 2, and the protective
ground conductor at terminal 3 (PE).
Note: Terminal 14 (ground) is internally linked to terminal 3 (PE).

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page 8 NES K05/0922
7.3 NE-304 Electrode Relay
The NE-304 electrode relay is a double relay with two
separated electrode circuits and one reference electrode. It
is supplied with a quiescent current relay, i.e., the relay
picks up (contact 3-4 and 6-7 close) when auxiliary power is
applied. If the electrodes are wetted or the power fails, the
relay disengages (contact 4-5 and 7-8 close). The signal
lamps (red LED`s) are energised when the relay picks up.
Electrode connection
Usage as Min./Max. switch (3 electrodes)
 Connect the ground or reference electrode to terminal 10.
 Connect Min.-switching electrode to terminal 12 and the Max.-switching
electrode to terminal 15.
Level Relay LED
Min-
electrode
Reaches or above the switching electrode relay drops out, contact 4-5 closed out
Below the switching electrode relay picks up, contact 3-4 closed on
Max.-
electrode
Reaches or above the switching electrode relay drops out, contact 7-8 closed out
Below the switching electrode relay picks up, contact 6-7 closed on
Usage as two interval controls (5 electrodes)
 Connect the ground or reference electrode (longest rod) to terminal 10.
 Pump 1: Connect the Max.-switching electrode to terminal 12 and the Min.-
switching electrode to terminal 13. Contact 3-4 is closed when the tank is
empty (LED 1-on). When the liquid reaches the Max. electrode, the relay
changes over and contact 4-5 closes (LED 1-out). The relay remains changed
over until the level falls below the Min. electrode. The interval then repeats
itself.
 Pump 2: Connect the Max.-switching electrode to terminal 15 and the Min.-
switching electrode to terminal 16. Contact 6-7 is closed when the tank is
empty (LED 2-on). When the liquid reaches the Max. electrode, the relay
changes over and contact 7-8 closes (LED 2-out). The relay remains changed
over until the level falls below the Min. electrode. The interval then repeats
itself.
 The changeover contact may be used for evacuating or filling—as shown in
the circuit examples.

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NES K05/0922 page 9
Usage as one interval control and one switch point (4 electrodes)
 Connect the ground or reference electrode (longest rod) to terminal 10.
 Pump 1: Connect the Max.-switching electrode to terminal 12 and the Min.-
switching electrode to terminal 13.
 Connect the switch point electrode to terminal 15.
Terminating the mains voltage
 The mains voltage is terminated at terminals 1 and 2, and the protective
ground conductor at terminal 9 (PE).
Note: Terminal 10 (ground) is internally linked to terminal 9 (PE).

NES
page 10 NES K05/0922
7.4 Application examples with Electrode Relay NE-104
P
M
Power supply
Power
supply
Draining the tank
P
M
Power supply
Power
supply
Filling the tank

NES
NES K05/0922 page 11
Power supply
Power
supply
Overflow protection
Power supply
Power
supply
Minimum level
protection

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page 12 NES K05/0922
8. Commissioning
Turn the sensitivity potentiometer fully clockwise to the right, until the stop is
reached.
When the mains voltage and the electrodes have been connected according to
their required function, the conductive limit switch is ready for operation. The tank
may now be filled. The sensitivity is optimally adjusted with this basic setting.
Should foaming cause the relay to operate too early, the sensitivity can be
reduced by turning the sensitivity potentiometer to the left, until the foam does not
cause the relay to operate.
9. Locating and Remedying Faults
The relay does not operate:
 Check that the mains voltage is applied to terminals 1 and 2. If the voltage is
present, the red LED should light up and the relay should pick up. If there is no
reaction, the relay is faulty.
 If the LED is energised
Relay NE-104: Disconnect the electrode from terminals 14, 15, and 16, and
short-circuit terminals 14 and 15 with a wire jumper. The relay must drop out
now. If there is no reaction, the relay is faulty.
Relay NE-304: Disconnect the electrode from terminals 10, 12, 13, 15, and 16,
and short-circuit terminals 10, 12 and 10, 15 with a wire jumper. The relay
must drop out now. If there is no reaction, the relay is faulty.
 If the relay switches, remove the short-circuiting link and connect the
electrodes according to the connecting instructions. Short-circuit the electrodes
at the tips with a wire jumper. If the relay does not change over now, there is a
cable interruption, or the electrode tips are insulated by deposits.
 If the relay with the wire jumper at the electrode tips changes over, remove the
wire jumper, adjust the maximum sensitivity on the relay, and immerse the
electrodes in the medium. If the relay still does not switch, the conductivity of
the medium may be too low.

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NES K05/0922 page 13
10. Maintenance
The Conductive Limit Switch requires absolutely no maintenance. The electrode
tips should be occasionally inspected for deposits or corrosion and should be
cleaned. Insulating deposits can cause a malfunction.

NES
page 14 NES K05/0922
11. Technical Data
Level Limit Switch
Housing: polyamide or aluminium
Connections: polypropylene, PTFE or
stainless steel 1.4571
G ½ (single electrode)
G 1 ½ (2-6-fold electrode)
Electrodes: stainless steel 1.4571, hastelloy
or titanium
Max. length of
electrodes: 3000 mm
Electrode coating: polyolefine, complete coating
PTFE complete or partial coating
No. of electrodes: 1…6
Max. temperature: 90 °C (polyolefine coating)
150 °C (PTFE coating)
Max. pressure: 6 bar (PTFE connection)
15 bar (polypropylene connection)
30 bar (stainless steel connection)
Min. conductivity: 20 µS/cm
Protection: IP 65
Electrode relay
NE-104, NE-304
Power supply: 230, 110, 24 VAC ± 15 %, 50 – 60 Hz
Power input: NE-104: approximately 2 VA
NE-304: approximately 4 VA
Floating voltage: approximately 10 VA
Short-circuit-current: approximately 0.5 mA
Sensitivity: adjustable 0 – 50 kΩ
Response time: approximately 1 sec.
Output: NE-104:
1 changeover contact
NE-304:
2 changeover contacts
Switch capacity: max. 250 VAC, 5 A, 600 VA
Housing: Macrolon
Protection: housing: IP 40
Terminals: IP 20
Ambient temperature: - 20 °C...+ 60 °C
Dimensions: 75 x 55 x 110 mm
Installation: DIN rail mount or
screw fixation
Signalling: LED red: monitoring state

NES
NES K05/0922 page 15
12. Order Codes
Model Description Housing Electrode
material
Electrode
coating
Screwed
fitting
Number
of electrodes
NES-
Conductive
Level
Limit Switches
R = Polyamide
L = Aluminium
E = Stainless
steel
H = Hastelloy C*
T = Titanium*
A =Polyolefine
complete
coating
T =PTFE
partial
coating
(300 mm)
V =PTFE
complete
coating
P = Polypropylene**
E = Stainless steel
F = PTFE*
1 = 1 electrode
2 = 2 electrodes
3 = 3 electrodes
4 = 4 electrodes
5 = 5 electrodes
6 = 6 electrodes
Please show the length of electrodes in clear text .
*with PTFE coating only (option T or V)
**with stainless steel electrode and polyolefine coating only
Order Codes for electrode relay
Description of electrode relay
Supply
Order no.
24 VAC
Order no.
230 VAC
Order no.
110 VAC
1 limit signal
or 1 min./ max. control NE-1042 NE-1040 NE-1041
2 limit signals
or 2 min./ max controllers NE-3042 NE-3040 NE-3041

NES
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13. Dimensions
13.1 Electrodes with Housing

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NES K05/0922 page 17
13.2 Electrode Relay

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14. Disposal
Note!
 Avoid environmental damage caused by media-contaminated parts
 Dispose of the device and packaging in an environmentally friendly
manner
 Comply with applicable national and international disposal regulations and
environmental regulations.
Batteries
Batteries containing pollutants are marked with a sign consisting of a crossed-out
garbage can and the chemical symbol (Cd, Hg, Li or Pb) of the heavy metal that
is decisive for the classification as containing pollutants:
Cd1 Hg2 Pb3 Li4
1. „Cd" stands for cadmium
2. „Hg" stands for mercury
3. „Pb" stands for lead
4. „Li" stands for lithium
Electrical and electronic equipment

NES
NES K05/0922 page 19
15. EU Declaration of Conformance
We, KOBOLD Messring GmbH, Hofheim-Ts, Germany, declare under our sole
responsibility that the product:
Conductive Limit Switch Model: NE-104, NE-304
to which this declaration relates is in conformity with the standards noted below:
EN 61326-1:2013
Electrical equipment for measurement, control and laboratory use - EMC
requirements - Part 1: General requirements
EN 61010-1:2011
Safety requirements for electrical equipment for measurement, control and
laboratory use - Part 1: General requirements
Also, the following EEC guidelines are fulfilled:
2014/30/EU EMC Directive
2014/35/EU Low Voltage Directive
2011/65/EU RoHS (category 9)
Hofheim, 02. May 2016
H. Peters M. Wenzel
General Manager Proxy Holder