The following OWEN equipment was used to develop the new control system:
- Operator touch panel SP310-B
- Frequency converter PChV2
- Programmable logic controller PLC110-30 [М02]
- Analog input module MV110-2А
- Heavy-duty power supply units BP60-24S and BP30-24S
- Power supply units BP60B-12
- Meyertec screw terminals
Before starting a shift, an operator switches on the system (exits the sleep mode) by pressing the corresponding button on the control panel and selecting the necessary baking program. After that, the system starts the main fan, which spins at the speed set in the settings (speed in a standby mode), and heats up the baking chamber by switching on/off a set of heating elements as per the preset value of the chosen first cycle program.
At the stage of heating-up, if the temperature differs greatly from the preset value, the operator will not be able to start the baking process (the start and stop buttons are locked). After the oven is heated up and the temperature reaches the preset value, the operator can start the baking process, and the system informs the operator about this with a sound signal.
The operator loads the trolley with future products into the baking chamber and presses the "Start" button on the touch panel screen. The products are baked according to the selected baking program consisting of 5 subprograms and the after-baking mode.
The following indicators can be set for each program:
- Subprogram time (the total baking time is calculated by summing time of 5 subprograms)
- Fan speed
- Chimney valve position (in %)
- Steam injection (in liters of water)
The number of subprograms in the baking program is selected by setting the process data (if there is no data, then this subprogram will not be executed).
The oven control system has many protective functions that prevent the operator from interfering with the baking process. In total, there are 100 baking programs.
There is also a manual baking mode. Upon completion of the baking program, the system offers the operator to switch to the after-baking mode, with an option to preset certain values. At the end of the baking process, the control system emits a loud sound signal.
On a whole, the new system appeared to be as effective as the original one, and even outperform it. The large touch screen facilitates the operator’s tasks. The control system can be used not only with Rothoterm WP ovens but also with rack ovens of other manufacturers, such as Miwe.
The project helped to stop using expensive imported equipment. Moreover, the client benefits from prompt technical support regarding the control system, which previously was not available.