Controlling the Bake of the Perfect Loaf Bread. Just thinking of the word pushes
With one heater above the conveyor and
your olfactory senses to imagine yeast-
the other below, each needs to be set to
based delights at the counter of your
a different temperature. Spare outputs
favorite bakery. But baking the perfect
from the Delta Temperature Controllers
loaf, and in large enough quantities,
were available and linked to relays for
demands furnaces that accurately
audible and visible alarm signals. These
control the process from beginning to
signals were also replicated in the DOP-
end. This was precisely the task faced by
107WV HMI.
Mechatronics Ltd., a system integrator and official distributor of Delta Motion,
Closely coupled with the quality of the
Drive, Control, and Robotics products
bake is the speed control of the conveyor
based in Bulgaria.
belt. The MS300 VFD is linked to an the conveyor was implemented using an
inductive proximity sensor that is easy to
The requirements for the bread furnace
MS300 Series inverter. This AC motor
clean and remains accurate in the dusty
machine defined four temperature zones.
variable frequency drive (VFD) also
baking environment. Installed closed to
The first zone is especially powerful to
supported the RS-485 Modbus interface
compensate for the cooled conveyor belt
the gears, the built-in programmable
and is ideal for open-loop control of IM
and the relatively cool loaf entering the
and PM motors.
logic controller (PLC) of the MS300 is
oven. At this step, steam is also injected into the furnace to give it that freshlybaked sheen. It is followed by three temperature-controllable baking zones that are carefully controlled for baking the optimal loaf. The conveyor belt of this traveling oven design must also be held at the correct speed throughout the
Of course, the quality of the bake is ultimately defined by the furnace. Special attention was given to selecting the optimal control approach for the seven heating elements used. After careful deliberation, the DTC1000 Temperature Controller was selected as the main
process. Rounding off the specifications
controller, with DTC2000 controllers used
was a human-machine interface (HMI)
in parallel for the remaining six heaters.
to configure the baking process, deliver
These are also connected to the Modbus.
temperature status of each zone, and
The selection of established, reliable
output any error status information.
components, along with the careful programming, were critical in delivering
For the HMI, the team selected the
a low-maintenance design that could be
Advanced HMI DOP-107WV from the
operated 24/7.
DOP-100 Series. This touch-based control panel features a 16:9 7» color TFT
To provide optimal temperature
screen with a modern-looking, narrow
regulation, the auto-tuning function of
frame. Its multilingual support meant it
the DTC1000/2000 was used. The inputs
was well-suited for the target market,
are acquired from third-party PT100
while user-friendly editing software
temperature sensors while control of the
ensured that the final user interface was
heating elements is implemented with
easy to navigate. With several RS-485
solid-state relays. Auto-tuning uses a
capable COM ports, it integrated perfectly
training process to configure the closed-
with the other components selected for
loop PID controller once the sensors
the furnace. Considering the operating
and heaters are installed in this 250
environment, the flat, wipeable surface
kW furnace. Further complicating the
of the DOP-107WV proved the ideal
implementation is the dual heating and
choice for a dusty bakery. Control for
sensing of the last three baking zones.
26 FDPP - www.fdpp.co.uk
configured to monitor and calculate the conveyor speed. This is continuously compared it to the setpoint defined in the HMI. Thus, the end-customer only needs to set the desired baking time, the required temperature, and then press run to start baking. The Mechatronics Ltd. team benefited from the broad range of industrial automation solutions in the Delta portfolio. Integration of the VFD, HMI, and Temperature Controller was simplified thanks to the out-of-the-box interoperability and connectivity of the components selected. Most people would assume that baking bread is very simple. On the contrary, the bread furnace project has highlighted the skill required of both bakers and engineers to create a machine that delivers the perfect loaf. The auto-tuning function of the DTC1000/2000 played a large part in ensuring that bakers can deliver a quality product every batch, by providing excellent temperature control,» said Victor Ogedegbe, Field Application Engineer at Delta. www.delta-emea.com
