The aim of this project is to create a modern and advanced program for controlling a vacuum furnace used for brazing plate heat exchangers and which includes functions for remote monitoring. A DAQ-unit (Data Acquisition) made by National Instruments connects with an already existing vacuum furnace to send control signals and receive measurements. There is already a control program available for the vacuum furnace but it has a number of shortcomings which the new program is intended to solve. A PID controller is implemented to control the temperature of the furnace. Temperature control is of utmost importance to get the brazing process as stable as possible. Therefore, a simulator has been developed that simulates the entire brazing process. The simulator serves as a tool to optimize values of the constants included in the PID control algorithm. Everything is written in the C# programming language. The braze process has from a code stand point been divided into five phases; lowering pressure, heating, brazing, cooling and finish. A comparison between the new and the old control software shows that heating process is much faster now and that when the correct temperature level has been reached, the temperature variation is considerably lower than before. The entire soldering process is shortened by almost two hours. Temperature control is more efficient and stable than before because of the constants calculated using the simulator and that a PID controller is used instead of a PD controller. New technology is implemented so that a much larger number of samples are obtained. Functions for user access to the history of previous brazing processes has been developed and an interface to easily adjust settings is implemented. Even a web interface for remote monitoring has been created.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:miun-26132 |
| Date | January 2015 |
| Creators | Persson, Christofer |
| Publisher | Mittuniversitetet, Avdelningen för informations- och kommunikationssystem |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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