Radio is seeing significant growth in a range of industries. In our field, data transfer from a sensor to its acquisition system conventionally takes place via a wired connection. The current trend is towards a radio link. Simple to install, this new technology in agri-food still has two restrictions:
– signal range (less and less of a problem),
– crossing capacity, for example radio waves do not cross metal.
To implement data transfer by radio in an autoclave, a cooking chamber, or any other metal and closed appliance, there are two possible methods:
1- Radio transmission within the chamber, then wire transmission via the reception antenna with a cable passing through the metal partition. The computer that displays the data in real-time is then connected by wire or by another radio relay .
2- Wired data transfer inside and through to the outside of the chamber, then a radio relay to the display computer.
The first method is attractive since it allows the instrumentation of autoclaves with fully computerized loading, but it also has major disadvantages:
– very high additional cost compared with purely wired instruments;
– considerable limitation of the number of sensors used simultaneously in the instrumented chamber;
– risks of communication failures with rotary autoclaves containing several metal separators.
The second method requires human intervention to connect the sensors after loading, but also offers some key advantages:
– no additional cost compared with purely wired instruments;
– no limitation of the number of sensors used simultaneously in the instrumented chamber;
– possibility of working in supervision on several chambers;
– no risk of a break in communication.