Kobold NBK-R series, NBK-RM series, NBK-RT series, NBK-RA series, NBK-RT200 Operating Instructions Manual

Operating Instructions

for

Limit switch

Model: NBK-R

NBK-RM
NBK-RT
NBK-RA

NBK-R...

page 2 NBK-R... K04/0617

1.Contents

1. Contents ........................................................................................................ 2

2. Note .............................................................................................................. 3

3. Instrument Inspection .................................................................................... 3

4. Regulation Use .............................................................................................. 3

4.1 Electrical limit switch ............................................................................ 4

5. Operating Principle ........................................................................................ 4

6. Mechanical Connection ................................................................................. 5

7. Electrical Connection .................................................................................... 6

8. Commissioning .............................................................................................. 7

9. Technical Information .................................................................................... 8

10.Order Codes ................................................................................................. 9

11.Illustrations .................................................................................................... 9

12.EU Declaration of Conformance .................................................................. 10

13.Type Examination Certificate ...................................................................... 11

Manufactured and sold by:

Kobold Messring GmbH

Nordring 22-24

D-65719 Hofheim

Tel.: [phone]

Fax: [phone]

E-Mail: [e-mail]

Internet: www.kobold.com

NBK-R...

NBK-R... K04/0617 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 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 or NBK-RA
 Operating Instructions

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 the limit switches are suitable for applications with a higher operating
temperature or for the use in hazardous areas.

NBK-R...

page 4 NBK-R... K04/0617

4.1 Electrical limit switch

- For standard applications NBK-R/NBK-RM: Bistable changeover contact fitted in

a polycarbonate housing with 3m connection cable

- For high temperature applications NBK-RT200/-RT400: Bistable changeover

contact fitted in an aluminium die cast housing with terminal connectors.

- For ATEX applications NBK-RA: Bistable changeover contact as an

encapsulated proximity switch fitted in metallic cast housing with 3 m connection
cable.

ATEX-marking for contact NBK-RA (encapsulated version):

II 2G Ex mb IIC T6 / T5 Gb
II 2D Ex mb IIIC IP67 T 105 °C Db

 Use the contacts appropriate and as intended.
 Make sure that only accessories are used in hazardous areas that meet

all the requirements of the European directives and national legislation.

The contacts NBK-RA with ATEX approval meet the requirements of category
2 GD. The proximity switches with ATEX approval are used in the following
zones:

 2G in zone 1
 3G in zone 2
 2D in zone 21
 3D in zone 22

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 bypass­tube within the measuring length.

The reed-contacts in the limit switches 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-R...

NBK-R... K04/0617 page 5

6.Mechanical Connection

NBK-R/NBK-RM

Mount and tighten the reed switch (NBK-R, NBK-RM
and NBK-RA) - if available - on the bypass tube at the
opposite side of the roller indicator with the provided
ribbon clamps (ex contact: two ribbon 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 during the float passes by, the preassembled
spacer (stainless steel) must be removed.

NBK-RA

NBK-RT200/400

The high temperature switch
RT200/400 will be mounted to the bypass
tube with the tube clip fixed at the contact
housing.

Th

ermal screening

(for 400°C-switch only)

Clamp