Kobold NBK-R User manual

Operating Instructions
for
Limit switch
Model: NBK-R
NBK-RM
NBK-RT
NBK-RV/RN

NBK-R...
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1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 4
4.1Electrical limit switch ............................................................................ 4
5.Operating Principle ........................................................................................ 5
6.Mechanical Connection ................................................................................. 6
7.Electrical Connection .................................................................................... 8
8.Commissioning NBK-R ............................................................................... 10
9.Technical Information .................................................................................. 11
10.Order Codes ............................................................................................... 12
11.Illustrations .................................................................................................. 13
12.Disposal ...................................................................................................... 14
13.EU Declaration of Conformance (NBK-R/NBK-RM/NBK-RT) ...................... 15
14.EU Declaration of Conformance (NBK-RV/RN) .......................................... 16
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

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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 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:
 Electrical Limit Switches Model: NBK-R/NBK-RM/NBK-RT/NBK-RV/RN

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4. Regulation Use
Any use of the device 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.
The Limit Switches for the NBK Bypass Level Indicators are used for continuos
measuring, display and monitoring of liquids in tanks or vessels. Depending on
the design they are suitable for applications with a higher operating temperature.
4.1 Electrical limit switch
- For standard applications NBK-R/NBK-RM: Bistable changeover contact fitted in
a polycarbonate housing with 3 m connection cable
- For high temperature applications NBK-RT200/-RT400: Bistable changeover
contact fitted in an aluminium die cast housing with terminal connectors.
NBK-RV/RN: Bistable changeover contact in aluminum housing with cable gland

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5. Operating Principle
Kobold Bypass Limit Transmitter are used for the monitoring of limit values in
tanks or vessels.
They are firmly attached with mounting plates and ribbon clamps to the Bypass
Level Indicator, model NBK, and can be moved to any position on the bypass-
tube within the measuring length.
The reed-contacts in the limit switches NBK-RV/RN react bistable and they are
switched by the magnetic float inside the NBK tube as passing by.
One or more limit switches can be mounted on the bypass.
NBK-RN/RV
The switching behaviour is bistable. Should the electrical supply fail and return,
the position of the impulse magnet will be "memorised". Because of its low mass
switching element this level switch is particularly suitable in installations with
strong vibrations. The level switch type NBK-RV200Nx has a Reed miniswitch for
low level AC/DC loads.
Type NBK-RN200Nx also contains a resistor circuit conforming to two-wire
sensors according to EN 60947-5 (NAMUR).
Fig.1: Schematic diagram NBK-RV200NO/NC
Fig.2: Schematic diagram NBK-RN200NO/NC
1
2
3
2

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6. Mechanical Connection
NBK-R/NBK-RM
Mount and tighten the reed switch (NBK-R, NBK-RM) - if
available - on the bypass tube at the opposite side of the
roller indicator with the provided fastening clamps. The
height of the switch contacts may be selected at will. The
cable connection must point downwards. The switch must
be attached close to the bypass tube. Due to technical
adaptations, it may come to malfunctions, when installing
new contacts in an existing plant. If the contact does not
switch when the float passes by it, the preassembled
spacer (plastic) must be removed.
NBK-RT200/400
The high temperature switch
RT200/400 will be mounted to the bypass
tube with the fastening clamp fixed at the
contact housing.
Th
erma
l
screen
i
ng
(for 400°C-switch only)
Clamp

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NBK-RN/RV
The switch is installed using the enclosed fastening clamps. The cable gland
must always point downwards. The switching point is about halfway up the
housing. The heat protection shield is situated between the switch box and the
mounting bracket.
ON (contact closed)
OFF (contact open)
fig.4: Mounting NBK-Rx200NC
OFF (contact open)
ON (contact closed)
level
level
fig.3: Mounting NBK-Rx200NO

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7. Electrical Connection
Limit switch NBK-R, NBK-RM, NBK-RT
Attention!
Observe the allowed electrical ratings for the limit switch.
Maximum values
NBK-R
NBK-RM
Standard-
contact
NBK-RT
High
temperature
contact
Switching capacity: 60 W/VA 80 VA
Switching current: 1 A 1 A
Switching voltage: 230 VAC/DC 250 VAC/DC
Install the switch (if available) according to the diagram and
connect it to the electrical controller.
When switching inductive loads, such as contactors,
relays, etc., electrical limit values should not be exceeded,
also temporarily by e.g. voltage peaks. The use of a
contact protection relay is recommended to avoid
overloading the reed contacts.
Valid regulations for hazardous areas, and regulations for
installation (DIN/VDE 0165), should be observed when
installing the NBK level indicator in zone 1 or 2 of
hazardous areas (no combustible liquids).
NBK-RT
NBK-R
NBK-RM

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NBK-RN/RV
The electrical wiring may only be carried out by trained specialists in compliance
with the relevant safety regulations. With switching voltages greater than 60V
(NBK-RV200Nx), the aluminum housing must be firmly connected to PE. The
usual protective measures must be taken for the reed contact.
Fig. 6: Electrical connection
NBK-RN200NO/NC
Fig. 7:
Protective measures for DC and
AC voltage

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8. Commissioning NBK-R
Commissioning of the electrical reed switch
Function of switches
All switches have three connection poles (black (2), blue (3) and brown (1)).
The black wire (2) is the common pole for both switching functions (N/C and N/O
contact).
The float must pass the switch once in both directions so that the switching func-
tion is in line with the terminal connection diagram and table below.
These instructions are often ignored when an alarm lamp is connected directly
with the result that the alarm lamp incorrectly indicates a fault.
When the switch has been passed, it is ready for operation and requires no
maintenance.
black
(
2
)
/ blue
(
1
)
black
(
2
)
/ brown
(
3
)
float above open closed
float below closed open
Hysteresis
Hysteresis is the difference between contact closing
and opening points. A hysteresis of approximately 15
mm float travel is achieved by factory tuning of the
float magnet and contact strength.