Ingenieurbuero Niehaus Engineering Office Niehaus - construction - energy technology - industrial design

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P & N "Lupo"
Controller
Requirements
Our solution
Realisation

The requirements:
Here, the job was the exact observance of a defined temperature. The juice used with this machine does not have any kind of preservation. So it is essential to keep the whole content of the machine at this defined temperature. Additionally it is required to shake the juice prior to tapping.
For the regulation it is neccessary to actuate the cooling element and the pump for the cooling fluid. Additionally, the cooling element has to be protected against overheating to secure a long lifetime. Further on, it is advantageous to have the possibility to change the regulation module without any need for adaption or calibration.
Consequently a digital solution was mandatory.

Picture: Board Lupo E
Our solution:

To keep the cicuit easy adaptable and simple, a microcontroller is used. The temperature sensors are adapted via an I2C-bus. This standard connection makes the controller easy to adapt to different types of sensors without calibration. However, the measured temperatures are meaningless without the right interpretation through the controller-program because of the impossibility to measure the temperature inside the juice.
A processor is used with the passive Lupo, too. It's main duty is here to prevent the other components from consuming too much current. The processor is in standby for its major lifetime, too. With this it was possible to reduce the average current consumtion to only some microamperes. The circuit and the LED-display is running for more than a year with only two AA-cells.
Picture: Board Lupo P

The Realisation:

From the first flowcharts up to the fully equipped and programmed board, the controller was developed and built in our office. The boards were developed with layout-software running under Linux. We could keep them single sided and without any bridges. So we could achieve low production cost. Programming was done with the aid of Atmel's original development tools running under Win 3.11 and later on with freeware running under Linux which, thanks to scripting possibilities and the simple command line interface, led to shorter test cycles.
At time a measurement- and service-computer is under development. When ready final checks in production and mobile customer service can be done without the need of PC-equipment and knowledge.
Picture: service-computer - layout
Ingenieurbüro Niehaus
Kleinbahnring 39
59469 Ense-Niederense


Tel : 02938 49095
Fax : 02938 49096
e-Mail : info@niekon.de

A 0.2.6 04/05/2002
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