Leksands Knäckebröd –Process monitoring with reliable sensors

Automatedtradition
The company “Leksands Knäckebröd” wasfounded in 1920 and has been family-owned
since then, today in the 4th generation.

Sensors support the crisp bread
production in Sweden
What is the most typical Swedish product?
It does not take long to give the answer:
crisp bread. In the little town of Leksand inCentral Sweden, there is Sweden’s largest
producer of the traditional round crisp
bred. Also involved: ifm as the automation
specialist.
While the recipes are still the same after about 100 years,
the production process is completely different now.
Production is automated according to the latest stateof-the-art technology. To ensure that the systems run
smoothly, different sensors monitor the production
process – from the supply of the ingredients to thedispatch area.
Capacitive sensors detect the flour
through the walls of the pipes.

Typical of Leksands’ crisp bread:the round shape with a hole in the middle.

Peter Joon, Managing Director at Leksands Knäckebröd: “We use many sensors since this is a very modern
production and a highly automated process. Since wehave a very high productivity of 99.6 %, we need sensors
we can trust and which are of high quality. Today we use
many sensors from ifm. They are of high quality andfunction very well with our products.”
Lars Ohlner, Automation Engineer at Leksands Knäckebröd adds, “We use products from ifm because they areeasy to configure and which are cost effective; they
simply function reliably. We mainly use photoelectric and„

Since we have a very high productivityof 99.6 %, we need sensors we cantrust and which are of high quality.
Today, we are using many sensors from ifm.

capacitive sensors and some flow sensors. This should
ensure a high degree of automation, good automation
and a reliable process.”
Some particularly innovative sensors as example:

n Capacitive sensors
The main ingredients of crisp bread are rye meal andfinely ground rye and wheat flour. They are supplied to the mixing tools via various pipes.
Capacitive sensors monitor the supply
at the pipes or the level in thetemporary storage tanks. Capacitive sensors are distinguished by detecting different
materials, even throughthe tank wall, unless they
are of metal. If a pipe is
no longer completely
filled with flour, the capacitive sensor detects
this state and sends aswitching signal to thecontroller.
Often, several capacitive
sensors are used on storage
tanks or silos, for example atthe very top, to signal a possible overflow in time or atthe very bottom of the silo to signal a critical empty state.
Potentiometers are used to adjust the sensors after installation. the switch point is adjusted depending on thewall thickness of the pipe and the type of the medium
to be detected. The new KI6000 sensors from ifm are tobe set particularly precisely. Since they have a unique LED
signal display for the perfect switch point setting.
The 12-point LED display makes it much easierfor the user to set the optimal switchpoint, which is in the centre of thedisplay. The green LEDs on eitherside of the switch point indicate the reliability of theswitch point. Deposits,material changes etc. aredirectly displayed on thesensor and the user canreadjust perfectly theswitch point as needed.
That means that an
imminent error can bedetected in good timeand avoided.
If help is needed with theeffects of process changes
this is much easier to explain„Leksands Knäckebröd –Process monitoring with reliable sensors

ifm is our first choice
when it comes to sensors
because they havethe products we need.

and rectify with the clear switch-point visualisation. Overthe phone the user can describe the LED behaviour anda support engineer can easily advise corrective measures.
By using non-contact potentiometers, the new units havethe high protection rating IP 69K and are perfectly suitedfor medium temperatures up to 110 °C. Moreover,different functions such as PNP/NPN or NC/NO can beselected. The ifm sensors are equipped with IO-Link andprepare the user optimally for Industry 4.0.

n O6 photoelectric sensor
Diffuse reflection sensors are installed at various places
in production. They monitor the flow of material on conveyor belts. These are, for example, individual slices ofcrisp bread but also completely packed products in thedispatch area.

The ifm O6-series diffuse reflection sensors
monitor the flow of material.

Even in the event of vapour, dust and highly reflective
environments the automatic sensitivity compensation

guarantees a reliable function. The clean round light spotin the operating area ensures a consistent light distribution in the light cone. Scattered light around the lightspot is avoided. The compact O6 WetLine is perfectlysealed. The two setting potentiometers are fitted with adouble seal. Front pane and potentiometer are embedded flush to allow residue-free cleaning. These compact
powerful units from ifm can also be supplied as throughbeam and retro-reflective systems.
The particularly resistant stainless steel housing with protection rating IP 68 / IP 69K ensures reliable use even

Distance measurement for position detection
across longer distances: O1D with time of flight technology.

The amount of water for dough production is precisely
detected by means of magnetic-inductive flow meters.

In most cases, they use the ifm diffuse reflection sensorsof type O6 at Lecksands Knäckebröd.
Their optical performance is excellent. They are distinguished by a particularly noise-immune background suppression while the range of up to 200 mm is independent ofthe object colour. This is important since the crisp breadslices have a different surface depending on the type andrecipes.

48

the object colour or its surface, e.g. mat or shiny. O1D isinsensitive to extraneous light up to 100,000 lux andremains unaffected even if direct sunlight hits the sensor
or object thus operating reliably and accurately at alltimes. The user can choose switching outputs, analogue
outputs or IO-Link for data provision.

n MID flow sensor
Besides the grain, water is an elementary part of thecrisp bread dough. In the field of dough production, amagnetic-inductive flow meter from ifm is used.
under severe conditions and ensures an extremely long lifetime. The O6 sensors are now also available as versions
with IO-Link. Via this interface, the range, sensitivity,
light-on / dark-on modes, switching delay or deactivationof the operating elements can, for example, be setremotely.

n O1D distance sensor
When position detection across longer distances is ofimportance, the O1D distance sensor is a cost-effectiveand also very precise problem solver. Thanks to laser
beam and time of flight measurement, it provides
reliable and precise distance measurement with a longrange of up to 10 m. It is ideal for applications with background suppression.
Thanks to the innovative on-chip time-of-flight processwith PMD technology, the detection is independent ofThese units feature high accuracy, measurement dynamics
and repeatability. They are suited for conductive media
as from 20 μS/cm. The 4-digit alphanumeric LED display
is highly visible. Besides the volumetric flow, the units alsomeasure temperatures from -10…70 °C. Furthermore,
an additional measuring point is no longer needed thanks
to the integrated temperature monitoring. The robust
compact housing, use of resistant materials and pressure
rating up to 16 bar allow flexible use.
Using the IO-technology, process values are not only
available via the analogue output but also digitally. Conversion losses during measured value transmission are athing of the past. Saving all sensor parameters not only
allows an easy replacement of sensors but also a simple
and quick configuration and remote parameter setting.
The user is well prepared for Industry 4.0 with the newIO-Link functionality.

n Continuing with ifm in the future
100 years of Swedish tradition:
Leksands are Sweden’s largest producers of crisp bread.

At Leksands, they have been using the reliable and longlife sensors from ifm for a long time. No wonder that you
can find ifm sensors which are older than 25 years insome places in the plant. Also in the future, they want totackle new challenges in automation with ifm as theirpartner.
Peter Joon: “For the future we have to develop sensors
that can perceive the different colours of the bread andtheir shades. ifm is part of the development of thesesensors. We have created a new area which is based
mainly on ifm products and which has proved its worth
so that we will further develop our future areas withsensors from ifm.”
He concludes, “ifm is our first choice when it comesto sensors because they have the products we need.”