Kobold RFS, RFS-1201 N4, RFS-12Ex N4, RFS-1200 N4 Operating Instructions Manual

Operating Instructions

for

Level Switch for Liquids

Model: RFS

RFS

page 2 RFS K02/0118

1. Contents

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

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

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

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

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

6. Use in Hazardous Areas ............................................................................... 4

7. Mechanical Connection ................................................................................. 5

8. Electrical Connection .................................................................................... 6

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

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

11.Dimensions ................................................................................................. 10

12.EU Declaration of Conformance .................................................................. 11

13.ATEX-Certificate ......................................................................................... 12

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

RFS

RFS K02/0118 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:

 Level Switch model: RFS
 Operating Instructions

4. Regulation Use

Model RFS devices are used for when monitoring liquid levels. The device should
only be used with liquids that are compatible with the unit’s materials of
construction.
Level control is often accomplished with at least two level switches - one acting to
sense the minimum level and the other for maximum level detection.

Any use of the Level Switch, model: RFS, 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.

RFS

page 4 RFS K02/0118

5. Operating Principle

The Level Switch RFS is designed for economical control of liquids in vessels.
The following three versions are available: A device with plug connection and two
devices with aluminium housing connection of which one is an ATEX-version for
the use in environment with gas explosion hazards. The switch is remarkable for
its maintenance-free design and small dimensions. The switch is mounted on the
side of the vessel. A hinged stainless steel float with a magnet floats up and down
through the liquid level. In the end position a potential-free reed contact is
operated by the magnet. The switching function (N/O contact / N/C contact) is
determined by the mounting position. The switching function is reserved by
simply rotating the switch through 180°.

6. Use in Hazardous Areas

With the approval the Level Switch, model RFS, can be used within hazardous
areas. Thereby the aluminium housing is applicable outside the process in zone
of category 2D. The float is appropriate for the use within the process in zone of
category 2D and 1D.

The approvals are as follows:

II 1 GD Ex ia IIC T6 Ga

-20≤Ta≤+60 °C

An additional intrinsically safe relay is required in environment with gas explosion
hazards (KFA…and respectively KFD).

For a correct and professional potential equalization, the ground terminal on the
housing of the RFS must be connected in applications in hazardous areas.

RFS

RFS K02/0118 page 5

7. Mechanical Connection

The Level Switch should be mounted so that the float can move freely over its
entire path without hitting the walls, floor or roof of the container. Avoid fitting the
switch where agitators or inlet valves could expose it to excessive turbulence.
Make sure that the medium does not contain solids or ferrite particles, as they
could collect on the float magnet and interfere with the switching operation. If the
liquid does contain sediment or suspended matter, you must be sure they do not
come into contact with the float system.

Mount the switch in a way that it is easily accessible for installation and
maintenance.

 Make sure that the allowed max. operational pressure and service temperature

for the device is not exceeded.

 The installation position must be horizontal.
 If possible, examine all the connection joints for proper sealing, just after

mechanical installation.

 The engraved arrow on the hexagon must point up or down depending on the

desired contact function. In any case the marked hexagon surface must always
be mounted vertically.

Mounting position

Depending on the mounting position of the device, the contact function (N/O or
N/C contact) of the level switch will be defined.

Mounted as
N/O contact

Mounted
as N/C

RFS

page 6 RFS K02/0118

8. Electrical Connection

Caution! Make sure that the voltage values of your system
correspond with the voltage values of the level switch.

 Make sure that the supply wires are de-energised.
 Connect your connection cable to the terminal of the aluminium housing or the

plug of the RFS level switch.

 The level switch has a protective insulation; a separate protection wiring for the

standard version is not necessary.

 For the RFS version for ATEX applications, the connection of the potential

terminal is mandatory.

 An additional intrinsically safe relay is required in environment with gas

explosion hazards (KFA…and respectively KFD).

Pin assignment for RFS Level Switch

RFS-1200N4 and RFS-1201N4

There are only two connection terminals which can be connected by choice and
which do not have any influence on the contact function (N/C / N/O). The contact
function is defined by the mounting position of the instrument.