KROHNE LS-4100 User Manual

Installation and
operating instructions

LS 4100/LS 4150

“Level-Safe”
Vibrating Level Switch

©

KROHNE 03/2002 7.02241.21.00

GR

Variable area flowmeters

Vortex flowmeters

Flow controllers

Electromagnetic flowmeters

Ultrasonic flowmeters

Mass flowmeters

Level measuring instruments

Communications engineering

Engineering systems & solutions

Switches, counters, displays and recorders

Heat metering

Pressure and temperature

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Safety information 2

Product liability and warranty 2

CE / EMC / Standards / Approvals 2

1 Product description 3

1.1 Function and configuration 3

1.2 Principle of operation 3

1.3 Technical data 4

1.4 Dimensions 6

2 Mounting 8

2.1 Mounting instructions 8

3 Electrical connection 10

3.1 Connection instructions 10

3.2 Wiring plan 11

4 Setup 14

4.1 Switching status 14

4.2 Switching point 14

4.3 Functions chart 14

5 Diagnostics 15

5.1 Function test 15

5.2 Replacement of the electronics 16

5.3 Maintenance 16

If you need to return a device for testing
or repair to KROHNE 17

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Please read this manual carefully, and also take note of country-specific installation standards
(e.g. the VDE regulations in Germany) as well as prevailing safety regulations and accident
prevention rules. For safety and warranty reasons, any internal work on the instruments, apart
from that involved in normal installation and electrical connection, must be carried out only by
qualified KROHNE personnel.

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Responsibility for suitability and intended use of these instruments rests solely with the operator.
Improper installation and operation of the instruments may lead to loss of warranty.
In addition, the ”General conditions of sale” forming the basis of the purchase contract are
applicable.
If instruments need to be returned to KROHNE, please note the information given on the last-but­one page of these Instructions. KROHNE regret that they cannot repair or check your instrument
unless accompanied by the completed form sheet.

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LS 4100/LS 4150 meet the protection requirements of
conjunction with
and

93/68/EEC

2

LS 4100/LS 4150

EN 50081-1

in conjunction with

(1992) and

EN 61010-1,

EN 50082-2

and also bear the

Directive 89/336/EEC

(1995), and

Directives 73/23/EEC

CE symbol

in

.

03/2002

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1.1 Function and configuration

LS 4100/LS 4150 detect levels of liquids with a viscosity of 0.2 up to 10.000 mPa s and a density
of ≥ 0.6 g/cm3. Modular construction enables their use in machines, plants, vessels and pipelines,
even in applications severely limited in space. Typical applications are overfill and dry run
protection.

LS 4100 is optionally available with threads G 1 A and 1" NPT. The stainless steel housing
(1.4571) is in protection class IP 67.

LS 4150 is mainly suitable for level detection in the food processing and pharmaceutical industry.
Due to the polished sensor surface (Ra ≤ 0.5 µm or Ra ≤ 1.5 µm) bacteria have no chance to
collect. LS 4150 is also suitable for CIP and SIP cleaning. Many different hygienic fittings such as
cone with compression nut, Tri-Clamp 1" and 2", bolting, Tuchenhagen VARIVENT or special
hygienic connections are available.

Due to the simple and rugged measuring system, LS 4100/LS 4150 is virtually unaffected by the
chemical and physical properties of the liquid. They work even under unfavourable conditions
such as turbulence, air bubbles, foam generation, build-up or varying products. An adjustment to
the medium is not necessary.

The electronics can be exchanged without problems. LS 4100/LS 4150 must not be removed.
LS 4100/LS 4150 has an integrated test switch which can be activated magnetically. It tests the

sensor electronics and the connected instruments.

1.2 Principle of operation

The tuning fork is piezoelectrically energised and vibrates at its mechanical resonance frequency
of approx. 400 Hz. This frequency is transferred to the electronics of LS 4100/LS 4150. When the
tuning fork is submerged in the product, the frequency changes. This change is detected by the
integrated oscillator and converted into a switching command.

By changing of poles of the supply voltage, the switching condition can be defined (max.
detection/min. detection). With the transistor version, PNP or NPN action can be preset by a
different connection of the consumer (load).

The integrated fault monitoring detects:

interruption of the connection cable to the piezo elements

•

extreme wear on the tuning fork

•

break of the tuning fork

•

no vibration

•

If one of the stated failures is determined or in case of voltage loss, the electronics takes on a
defined switching condition, e.g. the output transistor blocks.

LS 4100/LS 4150 3

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1.3 Technical data

Housing

Housing material stainless steel 1.4571/ 316Ti
Protection IP 67
Torque on the hexagon 80 Nm
Plug connection 4-pole plug
with status indication (illuminated ring)
Terminals max. 1 x 1.5 mm

Process connection

LS 4100

- thread G 1 A or 1" NPT

- material 1.4571 (316Ti)
LS 4150

- thread G 1 A or 1" NPT

- cone DN 25

- Tri-Clamp 1" or 2"

- bolting DN 40 or DN 50

- Tuchenhagen Varivent

- hygienic connection with compression nut F40 PN 25

- hygienic connection with tension flange DN 32 PN 25

Tuning fork

Material 1.4581 (stainless steel)

Weight

Total weight approx. 0.4 kg

Ambient conditions

Ambient temperature on the housing -40…+70°C
Storage and transport temperature -40…+70°C
Product temperature -40…+150°C

Ambient temperature on
the housing

2

Product
temperature

Operating pressure

max. 40 bar

Product

Viscosity 0.2…10.000 mPa s
Density

4

LS 4100/LS 4150

> 0.6 g/cm3

03/2002

Electronics - General

Integration time approx. 0.5 s
Measuring frequency approx. 400 Hz
Hysteresis approx. 4 mm with vertical installation
Control lamp illuminated ring with two-colour

LED for status indication
green – output conductive
red – output blocks

Electronics - Transistor output (SW E72 T)

Power supply 10 … 55 V DC
Power consumption max. 0.5 W
Output floating transistor output
NPN/PNP selectable
Load current max. 400 mA (output - overload and

permanently short-circuit proof)
Voltage loss max. 1 V
Turn-on voltage max. 55 V DC
Blocking current < 10 µA
Protection class II
Overvoltage category III
Mode A - max. detection or overfill protection
B - min. detection or dry run protection
A/B-mode by polarisation of the power supply

Electronics - contactless electronic switch (SW E72 C)

Power supply 20 … 250 V AC, 50/60 Hz or 20 … 250 V DC
Output contactless electronic switch
Internal current requirement approx. 3 mA (via the load circuit)
Load current min. 10 mA
max. 400 mA
(at I > 300 mA the ambient temperature can be

max. 60°C) max. 4 A up to 40 ms
Protection class I
Overvoltage category III
Modes A/B-mode by electrical connection
in the connection plug
A - max. detection, overfill protection
B - min. detection, dry run protection

CE conformity

LS 4100/LS 4150 vibrating level switches meet the protective regulations of EMC
(89/336/EWG) and NSR (73/23/EWG). Conformity has been judged acc. to the following
standards:
EMC Emission EN 50 081 - 1: 1992
Susceptibility EN 50 082 - 2: 1995
NSR EN 61 010 - 1: 1993

LS 4100/LS 4150 5

03/2002

1.4 Dimensions

LS 4100

Ø 40

265

Ø 29

129

100

25

30,5

Ø 60

SW41

G1A or 1”NPT

Optional with weld mark

Front side
O-ring seal

6

LS 4100/LS 4150

03/2002

LS 4100/LS 4150

LS 4100/LS 4150 7

03/2002

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2.1 Mounting instructions

In principle, the level switch can be mounted in any position. The instrument must be mounted
such that the tuning fork is at the height of the required switching point. Note the following
installation instructions:

Switching point

The tuning fork is provided with lateral markings (notches, 25 mm from the fork tip), marking
the switching point with vertical installation for the medium water. When installing level switch note
that the switching point of the instrument shifts when the medium has a density differing from
water (water = 1.0 g/cm

Switchin g p o in t w ith
lower density

Switchin g p o in t

Switchin g p oint
with higher
density

3

).

Switching
point

25

Switching
point

75

Fig. 2.1

Flow

(e.g. in pipes)
When mounting in pipes or in vessels with certain flow direction, you should mount level switch
such that the surfaces of the tuning fork are aligned with the direction of flow.

Adhesive products

In the case of adhesive and viscous products,

30 mm

the tuning fork should protrude into the vessel
to avoid build-up in the mounting boss. A
mounting boss should therefore not exceed a
length of 30 mm.

Fig. 2.2

In the case of horizontal mounting in adhesive
and viscous products, the surfaces of the tuning
fork should be vertical to reduce build-up on the

Top marking

tuning fork. The position of the tuning fork is
marked by two notches on the hexagon of
level switch. Therefore you can check the

Switching
point

position of the tuning fork when screwing it in.
One notch should be on top. When the hexagon
touches the seal, the thread can be still turned

Fig. 2.3

by approx. half a turn. This is sufficient to reach
the recommended installation position.

8

LS 4100/LS 4150

03/2002

Transport

Do not hold level switch on the tuning fork. The tuning fork can be damaged.
Polished version LS 4150
Treat instruments with polished tuning fork LS 4150 very carefully and do not touch the polished

surface. Unpack LS 4150 directly before mounting. Insert LS 4150 carefully into the provided
opening and avoid contact with vessel parts.

Cable entries
When mounting outside, on cooled vessels or in

humid areas in which e.g. cleaning is done with
steam or high pressure, the seal of the cable
entry is especially important. Use cable with
sufficient wire cross-section and tighten the
cable entry. For cables with too small wire
cross-section, a suitable reduction piece must
be used to ensure tightness of the cable entry.

Two seal rings are attached to the instrument to
ensure tightness also of cables with smaller
diameter. Use the smallest possible seal ring.

To avoid humidity ingress, the cable entry
should point downwards (see fig. 2.4).

Fig. 2.4

Proceed as follows: Loosen the plug by
unscrewing the knurled ring. Loosen the
connection screw and remove the socket insert
out of the angular housing of the plug (see also
fig. 3.1 under "3.1 Connection instructions").

You can turn the angle housing of the plug in
60° steps (see fig. 2.5). With vertically mounted
LS 4150, loop the connection cable to the

Fig. 2.5

instrument housing downwards so that rain and
condensation water can drain off.

Welded socket G 1 A
Level switch thread start is defined. This means that each is in the same position after screwing in.

Therefore remove the supplied seal from the thread of LS 4100/LS 4150. This seal is not required
when using a welded socket (G 1 A). Screw level switch into the welded socket.

You can determine the subsequent position of the level switch before welding (see also fig. 2.3).
Mark the appropriate position of the welded socket. Before welding, unscrew level switch and
remove the rubber ring from the socket.

An optional welded socket (G 1 A) is available
which is already provided with a notch. Weld

Marking

this socket with a marking facing up-wards.

Fig. 2.6

LS 4100/LS 4150 9

03/2002

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3.1 Connection instructions

Note

Switch off the power supply before starting connection work.
Remove the plug. Loosen the screw (7) and disassemble the plug. Lead the connection cable

through the cable entry and connect the cables according to the following illustration.

1 Socket insert

2 Angle housing

3 Seal ring (3 pcs. for different cable ø)

4 Clamping basket

5 Pressure screw

Fig. 3.1

Plug connection

Terminals 1 - 4 are marked on the plug.

6 Illuminated ring with LED

7 Connection screw

Fig. 3.2

10

LS 4100/LS 4150

03/2002

3.2 Wiring plan

Floating transistor output (SW E72 T)

Power supply: 10 … 55 V DC (for further information see the following connection examples as
well as technical data)

To determine the switching status of the transistor output (mode A/B), the supply cable (terminals
1 and 4) must be polarised respectively.

Mode A Mode B
Max. detection or overfill protection: Min. detection or dry run protection:

- terminal 1: + - terminal 1: –

- terminal 4: – - terminal 4: +

Through different connections of the consumer (load), NPN or PNP action can be preset. Take
care that during connection, terminal 2 has always a more positive voltage potential than terminal

3.
Connection examples

The transistor switches the supply voltage of the oscillator to the binary input of a PLC or to an
electrical load.

Mode A Mode B

UB

U

U

B

U

B

B

U

U

B

U

B

B

U

B

NPN action PNP action NPN action PNP action
The transistor switches a second voltage source with the same reference potential to the binary

input of a PLC or to an electrical load.

Mode A Mode B

U

U

U

B

U

B

B

U

B

U

B

B

U

U

B

B

NPN action PNP action NPN action PNP action

LS 4100/LS 4150 11

03/2002

The transistor switches a second, galvanically isolated voltage source to the binary input of a PLC
or to an electrical load.

Mode A

UB U

U

B

B

U

B

For mode B you have to switch the polarity of
terminals 1 and 4.

NPN action PNP action
Control of alternating current loads

The transistor switches a galvanically separated alternating voltage 10 … 42 V AC to a load.

Mode A

U

U

B

B

Note

The transistor outputs of several LS 4100/

LS 4150 can be switched in series or in parallel

to connect their signals logically.

The connection must be made such that

terminal 2 always has a higher voltage

compared to terminal 3.

Contactless electrical switch (SW E72 C)
Power supply 20 … 250 V AC, 50/60 Hz or 20 … 250 V DC (for further information see the

following connection examples as well as the technical data)
For direct control of relays, contactors, magnet valves, warning lights, horns etc. the instrument

must not be operated without connected load (switching in series), as the oscillator can be
destroyed when connected directly to mains. Not suitable for connection to low voltage PLC
inputs.

The domestic current is temporarily lowered below 1 mA after switching off the load so that
contactors, the load current of which is lower than the permanently flowing domestic current of the
electronics, are reliably switched off.

12

LS 4100/LS 4150

03/2002

A/B-mode
Mode A Mode B

Max. detection, overfill protection Min. detection, dry run protection

In mode A, terminal 3 remains free. Therefore do not connect a cable to terminal 3, not even up to
the next junction box, since the cable can pick up interfering signals.

LS 4100/LS 4150 13

03/2002

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4.1 Switching status

The switching status can be checked with closed instrument by means of the illuminated ring in
the upper part of the housing.

By interchanging of the connection cables, you can modify the switching status of the transistor
output (T). For the electronics version contactless electronic switch (C) you have to use a jumper
in the plug between terminal 2 and 3 to modify the switching status. You can adjust the requested
mode acc. to "4.3 Functions chart" (see "3.2 wiring plan").

A = max. detection or overfill protection,
B = min. detection or dry run protection.

4.2 Switching point

The switching point of LS 4100/LS 4150 is
preadjusted and does not require further
modifications.

The statements on the position of the switching
point (see also "2.1 Mounting instructions")
relate to water (density 1.0 g/cm3). For mediums
with a different density, this switching point
shifts, depending on the density and the
installation, in the direction of the housing or
tuning fork tip.

A density change of 0.1 g/cm3 results in a
shifting of the switching point by approx.

2.5 mm.

Switching point with
lower density

Switching point

Switching point
with higher density

25 mm

Fig. 4.1

4.3 Functions chart

The following chart provides an overview of the switching conditions dependent on the ad-justed
mode and level. To set the mode, please read the information in "3.2 Wiring plan".

Level

individual individual

Transistor (T)
Contactless electrical

switch (C)

conducts blocks conducts blocks blocks blocks

Switch

closed

Signal lamp

green

14

LS 4100/LS 4150

Mode A Mode B

Switch
open

red

Switch
closed

green

Switch
open

red

Response
of the fault
monitoring

Switch
open

red

03/2002

Failure of the
supply voltage

Switch
open

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5.1 Function test

LS 4100/LS 4150 are equipped with an
integrated test switch which can be activated
magnetically. Proceed as follows to test the
instrument:

Make sure that the tuning fork is

•

uncovered.
Hold the test magnet (accessory) to the

•

magnet symbol on the instrument housing
(see fig. 5.1). The test magnet simulates a
covering of the tuning fork. If the tuning fork
is uncovered, the signal lamp of the level
switch changes status. The electronics and
the switching output of the level switch are
checked now. Note that the connected
instruments will be activated during the
test.

If, despite several tests with the test magnet,
LS 4100/LS 4150 does not switch over, check
the plug connection and the connection cable
and test the instrument again. If there is no
switching function, the electronics is defective.
In this case you have to replace the electronics
(see "5.2 Replacement of the electronics") or
send the instrument to our repair department.

Note:

It is absolutely necessary that you remove the
test magnet after the test from the instrument
housing.

Fig. 5.1

LS 4100/LS 4150 15

03/2002

5.2 Replacement of the electronics

The removal of the electronics unit will damage
the housing seal. Therefore only open the
instrument if you want to insert a new
electronics unit.
To replace the electronics in case of failure, the
instrument must not be removed. Proceed as
follows to replace the electronics unit:

Separate level switch from operating

•

voltage.
Loosen the plug (1), by screwing on the

•

knurled ring.
Loosen the plug insert (2) with a screw-

•

driver on the four slots (10) and pull it care­fully out of the housing (6).

Remove the plug of the two connection

•

cables (7) from the socket on the board (8).
Grease (thin layer) the seal ring (4) of the

•

new plug insert with an acid-free grease.
Insert the connection cables (7) into socket

•

(8) on the board of the new oscillator.
Lower the plug insert (2) into the housing.

•

Make sure that the locking tab (3) is
approximately above the notch on the
housing edge (5).

Carefully push the plug insert (2) from

•

above into the housing (6). Push the four
snap-on hooks (9) with a screwdriver
inwards so that the plug insert can be more
easily inserted into the housing. Make sure
that the board does not get damaged.

Push the plug insert (2) flush to the housing

•

(6). Make sure that the locking tab (3)
snaps into the notch on the housing (5).
You can hear it when the snap-on hooks
(9) snap in the groove inside the housing. It
is not possible to loosen the parts without
damage.

Now screw the plug (1) back onto the

•

housing.

The level switch is again ready for use.
Note that the switching point may change slightly because of the electronics replacement.

1 Plug

2 Plug insert

3 Locking tab

4 Seal ring

5 Notch

6 Housing

7 Connection plug

8 Socket

9 Snap-on hooks (4 pcs.)

10 Slots (4 pcs.)

Fig. 5.2

5.3 Maintenance

LS 4100/LS 4150 are maintenance-free.

16

LS 4100/LS 4150

03/2002

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Your instrument has been carefully
manufactured and tested. If installed and
operated in accordance with these operating
instructions, your instrument will rarely present
any problems. Should you nevertheless need
to return an instrument for checkout or repair,
please pay strict attention to the following
points:

Due to statutory regulations concerning
protection of the environment and
safeguarding the health and safety of our
personnel, KROHNE may only handle, test
and repair returned instruments that have been
in contact with liquids if it is possible to do so
without risk to personnel and environment.

This means that KROHNE can only service
your instrument if it is accompanied by a
certificate in line with the following model
confirming that the instrument is safe to
handle.

Specimen certificate

Company: ........................................................... Address: .................................................................

Department:........................................................ Name:.....................................................................

Tel. No.:.............................................................. Fax No.:..................................................................

The enclosed instrument

Type:................................................................... .:..............................................................................

KROHNE Order No. or Series No ...................... ................................................................................

has been operated with the following process liquid

Because this process liquid is
water-endangering * / toxic * / caustic * / flammable*
we have

- checked that all cavities in the instrument are free from such substances *

- flushed out and neutralised all cavities in the instrument *

(* delete where not applicable)

We confirm that there is no risk to man or environment through any residual liquid contained in the
instrument.

Date: ..................................................................... Signature ..............................................................

..............................................................................

Company stamp:

If the instrument has been operated with toxic,
caustic, flammable or water-endangering liquids,
you are kindly requested

to check and ensure, if necessary by rinsing

•

or neutralising, that all cavities in the
instrument are free from such dangerous
substances.
(Directions on how you can find out whether
the primary head has to be opened and
flushed out or neutralised are obtainable
from KROHNE on request.)

to enclose a certificate with the instrument

•

confirming that the instrument is safe to
handle and stating the liquid used.

KROHNE regret that they cannot service your
instrument unless it is accompanied by such a
certificate.

................................................................................

LS 4100/LS 4150 17

03/2002

Notes

18

LS 4100/LS 4150

03/2002

Notes

LS 4100/LS 4150 19

03/2002